| T.R | Title | User | Personal
Name | Date | Lines |
|---|
| 456.1 | RE 456.0 | MTWAIN::KLAES | Know Future | Tue Aug 30 1988 14:03 | 9 |
| Briefly, ULYSSES will study the Sun's polar regions, which are
not visible from Earth, and MAGELLAN will radar map the surface
of the planet Venus.
If I or someone else gets hold of more information, could they
please put it here? Thanks.
Larry
|
| 456.2 | | STAR::HUGHES | | Tue Aug 30 1988 14:21 | 21 |
| They are two of NASA's much delayed new planetary missions. Ulysses
(aka International Solar Polar Mission, or something similar with
those initials) is a joint NASA/ESA mission, and ESA are not happy
with the delays. They have recently had to perform some major work
on the electronics, partly as a result of the delays.
Ulysses will be placed into a solar polar orbit, i.e. out of the
ecliptic, the plane which includes the orbits of all of the planets,
except Pluto. It will be the first to use such an orbit and one of very
few spacecraft (maybe the second?) to leave the ecliptic.
Magellan will enter orbit around Venus.
Both were to have used the Centaur G-Prime, launched from the shuttle
payload bay. They will now use the IUS or IUS/PAM-D upper stages,
with slower, more complex flight paths as a result.
If noone else gets to it first, I'll try to type in some details
later this week.
gary
|
| 456.3 | | MEMIT1::SCOLARO | A keyboard, how quaint | Tue Aug 30 1988 14:22 | 32 |
| ULYSSES:
Is the ESA portion of what was suposed to be a joint ESA/NASA effort to
sturdy the north and south polar regions. The NASA portion was
cancelled early in the Regan Administration. The spacecraft will
explore things like the sun's magnetic field, solar wind, etc from a
never befor seen position, the pole.
MAGELLAN:
Will use some spare parts, including a spare VOYAGER (or is it Galieo?)
communications antenna as a radar/communications antenna, to perform a
low cost high resolution synthetic aperature radar (SAR) mapping of
Venus. Pioneer Venus also did SAR mapping, but with a resolution
several orders of magnitude less than Magellan will.
Magellan is the first Regan era satelite. It channels the same
ingenuity that enabled Voyager to still be effective at transmitting
data from 4 times further out than it was designed for, to cut costs.
The scientists initially wanted a circular orbit for the SAR, but that
uses lots of fuel and that means more cost. The scientists wanted
continuous data, that means two antennas and at least one system to
point one antenna.
The engineers at JPL, gave the scientists a means to use the SAR on a
eliptical orbit, at the lowest points in the orbit and then use the SAR
antenna to transmit the data from each pass to earth. It is a much
slower means of collecting the data, but the "engineered" concept was
something like 1/2 the cost, not insignificant on $250 million projects.
Tony
|
| 456.4 | MAGELLAN rollout tomorrow | MTWAIN::KLAES | No atomic lobsters this week. | Mon Sep 26 1988 16:05 | 34 |
| Newsgroups: sci.space
Path: decwrl!labrea!agate!pasteur!ames!yee
Subject: MAGELLAN spacecraft rollout ceremony (Forwarded)
Posted: 22 Sep 88 21:20:43 GMT
Organization: NASA Ames Research Center, Moffett Field, CA
Charles Redmond
Headquarters, Washington, D.C. September 22, 1988
NOTE TO EDITORS:
MAGELLAN SPACECRAFT ROLLOUT CEREMONY
NASA's Magellan spacecraft, one of the agency's high-priority
science missions, will officially "rollout" at 12 noon EDT, on Sept.
27, 1988, during a ceremony from the Martin Marietta facilities,
Denver, Colo.
A press conference will follow the ceremony featuring officials
from NASA Headquarters, the Jet Propulsion Laboratory and Martin
Marietta, an astronaut crew member of the mission and a noted
planetary scientist. Other activities will include a spacecraft
viewing and photo opportunity, a tour of the Martin Marietta
facilities (where the spacecraft was designed, constructed and tested)
and an award reception for employees who worked on the spacecraft.
Scheduled to be launched on an April 1989 Space Shuttle flight,
Magellan will map -- in great detail -- the planet Venus. Once
launched Magellan will be the first U.S. planetary space mission in
over 10 years.
Magellan is scheduled to be shipped to NASA's Kennedy Space
Center, Fla., on Oct. 3, 1988, arriving 4 days later.
|
| 456.5 | MAGELLAN damaged by electrical fire | MTWAIN::KLAES | Saturn by 1970 | Mon Oct 24 1988 20:48 | 152 |
| Newsgroups: sci.space
Path: decwrl!labrea!agate!helios.ee.lbl.gov!lll-tis!ames!yee
Subject: Magellan spacecraft damaged by electrical fire (Forwarded)
Posted: 22 Oct 88 17:46:37 GMT
Organization: NASA Ames Research Center, Moffett Field, CA
Paula Cleggett
Headquarters, Washington, D.C. October 18, 1988
ADVISORY:
MAGELLAN SPACECRAFT DAMAGED BY ELECTRICAL FIRE
The Magellan spacecraft experienced a localized electrical fire
when workers connected cables around 11:00 p.m. EDT, Monday, Oct. 17,
1988. Housed at the Kennedy Space Center's Spacecraft Assembly and
Encapsulation Facility 2, the spacecraft was undergoing a routine
power systems check.
Within 1 minute the fire was extinguished. No personal injuries
resulted. The launch date for Magellan, set for April 1989, is not
expected to change.
A preliminary review shows that during the process of mating
electrical cables, in the forward equipment module, a circuit was
shorted, causing an overheated battery.
NASA will assemble today an investigative review board to assess
the cause and extent of damages. The assessment is expected to be
available next week.
Newsgroups: sci.space
Path: decwrl!labrea!agate!pasteur!ames!yee
Subject: Magellan investigative review board named (Forwarded)
Posted: 22 Oct 88 17:54:18 GMT
Organization: NASA Ames Research Center, Moffett Field, CA
Paula Cleggett
Headquarters, Washington, D.C. October 20, 1988
RELEASE: 88-141
MAGELLAN INVESTIGATIVE REVIEW BOARD NAMED
Jon R. Busse, director of engineering at NASA's Goddard Space
Flight Center (GSFC), Greenbelt, Md., will head the investigative
review board appointed to analyze damages to the Magellan spacecraft
during a power systems check at Kennedy Space Center (KSC), Fla.,
Monday night, Oct. 17, 1988.
The board will determine what caused a localized electrical fire
in a test battery, why this occurred and how to prevent such a mishap
in the future.
Members of the board include: Chester Vaughan, chief of the
Propulsion and Power Division, Johnson Space Flight Center, Houston;
William Mahoney, chief of the Payload Processing Division, KSC; Brian
Keegan, deputy director of the Office of Flight Assurance, GSFC; and
G. Ernest Rodriquez, staff engineer in the Space Power Applications
Branch, GSFC.
Members serving in an advisory but non-voting capacity include:
Josef Wonsever, on safety issues, NASA Headquarters, Washington, D.C.;
Douglas Hendrikson, as counsel, KSC; and George Diller, on public
affairs, KSC.
Members selected to observe include: Charles J. Sawyer, manager
of Payload Aerosystems, NASA Headquarters; Raymond L. Heacock, deputy
assistant laboratory director, Jet Propulsion Laboratory, Pasadena,
Calif.; and William Piotrowski, program manager for Magellan, NASA
Headquarters.
Preliminary results of this investigation are expected to be
available within a week. The launch date for Magellan, set for April
1989, is not expected to change.
Newsgroups: sci.space
Path: decwrl!labrea!agate!pasteur!ames!yee
Subject: Magellan Status 10/20/88 (Forwarded)
Posted: 22 Oct 88 17:56:56 GMT
Organization: NASA Ames Research Center, Moffett Field, CA
October 20, 1988
The Magellan Electrical Mishap Investigation Board resumed
meeting today. The activity during the morning was focused on
developing a list of action items for Martin Marietta, the Jet
Propulsion Laboratory, and NASA-KSC to support the investigation.
The board is requesting to inspect additional physical evidence,
the procedure in use at the time of the mishap, and to see the
history and supporting documentation of the components involved.
Testing has been directed to understand electrical conditions
which were present in the mishap as observed from the damaged
parts.
A procedure is under development for safing the damaged
battery in a manner consistent with preserving its evidence.
This will be followed by testing at the KSC malfunction analysis
laboratory.
Failure board chairman Jon Busse has divided the panel into
two groups. One group will study procedures and quality
assurance, and the other group will conduct an analysis of the
evidence. Over the next few days the board will meet in full
and also in groups. The panel hopes to begin drafting a report
next week.
At the SAEF-2 planetary checkout facility, cleaning of the
Magellan spacecraft forward equipment module has begun.
Technicains are experimenting with several solvents to determine
which will be most effective in removing soot or other observed
contaminant.
George Diller
NASA-KSC
Approved: Jon R. Busse, Chairman
Magellan Electrical Mishap Investigation Board
Newsgroups: sci.space
Path: decwrl!labrea!agate!pasteur!ames!yee
Subject: Magellan Status for 10/21/88 (Forwarded)
Posted: 22 Oct 88 17:59:06 GMT
Organization: NASA Ames Research Center, Moffett Field, CA
October 21, 1988
The Magellan Electrical Mishap Investigation Board met in
full this morning, then for the remainder of the day divided into
the two assigned groups studying evidence and procedures. The
planned activity schedule for the panel will be the same for
Saturday and Sunday.
Magellan is at the SAEF-2 planetary spacecraft checkout
facility where it has been since its arrival at KSC on October 8.
At the direction of the board, work allowed on the spacecraft
since the mishap has been inspection and cleaning. Swatches of
soot and other observed contaminants have been taken from the
spacecraft forward equipment module to analyze the composition
and test for the most effective solvent that can be used for
cleaning.
The board has now authorized other spacecraft work to
proceed which included removing the other test battery from the
spacecraft and other work necessary to maintain schedule.
George Diller
NASA-KSC
Approval: John R. Busse, Chairman
Magellan Electrical Mishap Investigation Board
|
| 456.6 | MAGELLAN status update | MTWAIN::KLAES | Saturn by 1970 | Fri Oct 28 1988 14:51 | 27 |
| Newsgroups: sci.space
Path: decwrl!labrea!agate!helios.ee.lbl.gov!pasteur!ames!yee
Subject: Magellan Status for 10/26/88 (Forwarded)
Posted: 26 Oct 88 18:05:05 GMT
Organization: NASA Ames Research Center, Moffett Field, CA
October 26, 1988
The Magellan Electrical Mishap Investigation Board met in
their respective groups this morning. This afternoon the full
board is convened to review and discuss the drafts of the
conclusions reached by the two subcommittees. A first review of
the drafts was accomplished during the board's afternoon session
yesterday, which lasted until early evening.
The subcommittes continue to analyze and discuss test
results from the KSC Malfunction Analysis Laboratory, and to
assess the procedures which were in use at the time of the
mishap. The findings and recommendations are now under
development by the full board.
George Diller
NASA-KSC
Approved: Jon Busse, Chairman
Magellan Electrical Mishap Investigation Board.
|
| 456.7 | MAGELLAN fire not too serious, but still unwelcome | MTWAIN::KLAES | Saturn by 1970 | Fri Dec 02 1988 15:02 | 26 |
| Newsgroups: sci.space,sci.space.shuttle
Path: decwrl!labrea!agate!pasteur!ames!ubvax!lll-winken!uunet!attcan!utzoo!henry
Subject: Space news from October 24 AW&ST
Posted: 30 Nov 88 06:13:50 GMT
Organization: U of Toronto Zoology
Xref: decwrl sci.space:8779 sci.space.shuttle:3001
NASA board to complete review of the Oct 17 electrical fire in the
Magellan Venus radar mapper. Damage is believed to be minor, and it
is not likely to affect the late-April launch. Repairs will probably
take about a week, mostly just to clean off soot and dirt. Much of
the spacecraft was still in shipping covers, and major electronics
packages had not yet been installed. The problem occurred when a
technician inserted a connector into the wrong socket on a test
battery in an electrical-system test. The fire was small and was put
out within a minute with a hand extinguisher. Test procedures will be
reviewed: the connectors cannot be inserted all the way into the
wrong socket, but apparently they can be inserted far enough to make
some contact.
SunOSish, adj: requiring | Henry Spencer at U of Toronto Zoology
32-bit bug numbers. | uunet!attcan!utzoo!henry henry@zoo.toronto.edu
========================================================================
Received: by decwrl.dec.com (5.54.5/4.7.34)
id AA12032; Wed, 30 Nov 88 08:26:03 PST
|
| 456.8 | MAGELLAN on display at KSC | MTWAIN::KLAES | Saturn by 1970 | Wed Dec 07 1988 14:37 | 45 |
| Newsgroups: sci.space
Path: decwrl!labrea!agate!eos!ames!yee
Subject: Editors Note: Magellan briefing and spacecraft showing Dec. 7
Posted: 6 Dec 88 05:20:24 GMT
Organization: NASA Ames Research Center, Moffett Field, CA
[Posted because it might be of interest, although it has been
edited to remove some press instructions. -PEY]
Paula Cleggett
Headquarters, Washington, D.C.
George H. Diller
Kennedy Space Center, Fla.
EDITORS NOTE: MAGELLAN BRIEFING AND SPACECRAFT SHOWING DEC. 7
The primary payload to be launched April 28, 1989, on the STS-30
Space Shuttle mission will be the topic of a briefing and photo
opportunity on Wed., Dec. 7, noon EST, at Kennedy Space Center, Fla.
Magellan, a spacecraft bound for Venus to radar map its surface,
is in KSC's SAEF-2 planetary spacecraft checkout facility. The
spacecraft will be almost fully assembled.
The briefing at the KSC news center will precede the showing.
Participating will be Dr. Stephen Saunders, Magellan project
scientist, and Gary Parker, Magellan spacecraft manager, both with
NASA's Jet Propulsion Laboratory; and Charlie Brown, director,
Magellan project, Martin Marietta Astronautics Group.
After the briefing, media will be provided transportation and
escort to the spacecraft cleanroom. Because of Magellan's
susceptibility to certain contaminants, those attending the showing
are asked to refrain from using hairspray or makeup on the day of the
event. Also, long pants and low-heeled, closed-toed shoes will be
required to access the cleanroom area. White room attire will be provided.
Because access to the spacecraft is on a non-interference basis
with testing, media may wish to keep in touch with the news center to
be certain that there has been no change in the date or time of the
event. The briefing will be carried on NASA Select television, Satcom
F2R, transponder 13, 72 degrees west longitude, with two-way question
and answer capability.
|
| 456.9 | Do they know something we don;t? | DECWIN::FISHER | Burns Fisher 381-1466, ZKO3-4/W23 | Wed Dec 14 1988 20:16 | 9 |
| re .8: Contrast the instructions to the press here with what was
required of the press who were shown the Soviet Phobos probe. (I.e.
nothing. And in addition, the Soviets apparently disconnected the
probe from its clean air purge so the press could see it better.)
Odd huh?
Burns
|
| 456.10 | Why MAGELLAN burned | MTWAIN::KLAES | Saturn by 1970 | Fri Dec 16 1988 13:30 | 39 |
| Newsgroups: sci.space,sci.space.shuttle
Path: decwrl!labrea!eos!ames!pacbell!att!chinet!mcdchg!clyde!watmath!utgpu!
Subject: Space news from November 14 AW&ST
Posted: 14 Dec 88 05:42:33 GMT
Organization: U of Toronto Zoology
Xref: decwrl sci.space:9074 sci.space.shuttle:3113
Investigating board concludes, as expected, that the electrical
fire on Magellan was the result of a technician's inability to see
what he was doing, and his incorrect assumption that battery
connectors could not be mated incorrectly. (True, but they could be
mated far enough for some contacts to meet.) Board recommends a
change in connector design, an alert to test personnel, and temporary
removal of obstructing panels so that the technicians can see the
connections they are trying to make.
ESA prepares to select its next major space-science project, out
of five possibilities: Cassini mission to Saturn and Titan (joint
project with NASA, ESA supplying the Titan descent probe), GRASP
(gamma-ray astronomy satellite), Vesta asteroid/comet encounter (joint
project with USSR, ESA supplying encounter module including
penetrators), Lyman faint-object spectroscopic astronomy satellite,
and Quasat very-long-baseline radio astronomy observatory. ESA's
advisory council recommended Cassini, but its recommendations are not
binding. One problem with Cassini is that it's a joint project with
NASA, historically an unreliable partner, and assumes prompt
Congressional approval of NASA's part of it. Failing Cassini, the
council recommended re-opening competition among the four remaining
projects. Actually, ESA has its own budget problems, since most of
this assumes modest annual space-science budget growth, which Britain
has been vetoing (such base-budget decisions must be unanimous). Many
of these projects have been waiting in the wings for several years, as
both Lyman and Quasat were originally joint work with NASA, and GRASP
was designed for shuttle deployment; the chaos within NASA after
January 1986 scuttled those plans.
SunOSish, adj: Requiring | Henry Spencer at U of Toronto Zoology
32-bit bug numbers. | uunet!attcan!utzoo!henry henry@zoo.toronto.edu
|
| 456.11 | MAGELLAN on schedule; mission details | MTWAIN::KLAES | No guts, no Galaxy... | Fri Jan 20 1989 16:53 | 125 |
| MAGELLAN ON TRACK FOR 1989 LAUNCH - can881224.txt - 12/7/88
The Magellan Venus radar mapping spacecraft is on schedule for a
launch aboard the Space Shuttle on April 28, 1989, and has not
suffered from a small fire involving a battery a few weeks ago.
And in a related area, a handling accident with an Inertial Upper
Stage is not expected to delay the STS-29 Shuttle mission in February
(see CAN881225.txt).
Officials from Kennedy Space Center, the Jet Propulsion
Laboratory, and Martin Marietta Aerospace briefed reporters on
Magellan in a press conference at Kennedy this morning.
Magellan is built from hardware remaining after the Voyager and
Viking projects and borrowed from Galileo. The 3.7-meter high-gain
antenna, for example, is from the Voyager backup spacecraft. A number
of components were to be taken from Galileo spares, which created an
interesting payback problem when Galileo fell behind Magellan in the
launch queue.
Despite using "leftovers," JPL Spacecraft Manager Gary Parker told
reporters: "I don't think we compromised anything in terms of putting
together a class-A mission."
The primary goals of Magellan are to provide high-resolution
imagery and altimetry data of 70 percent of the surface of Venus and
resolutions of 120 and 30 meters, respectively. Its secondary mission
includes mapping the remaining 30 percent of the surface and providing
gravimetric data on the planet interior.
"Magellan will send 100,000 times as much data as Mariner 2," said
Project Scientist Stephen Saunders of JPL. Because the atmosphere of
Venus is much thicker that that of Earth and lacks liquid water,
Saunders said that weathering effects are expected to be minimal and
that imagery of the surface will display tectonic features "in nearly
their pristine form."
To date the best resolution of Venus was provided by the Soviet
Venera 15 and 16 spacecraft which covered a quarter of the planet at a
resolution better than Pioneer 12 (which just marked its 10th
anniversary) but only a 10th as good as that planned for Magellan.
The Venera images have shown a number of interesting features that
Magellan will investigate, including a circular 600-km-wide feature
called Corona by the Soviets and having a ridge or fracture pattern
around its circumference. The Veneras also discovered a feature called
arachnoids--for their spider-like patterns--which have ridges hundreds
of kilometers long emanating from craters. Other images show regions
that are similar to sea-floor spreading, but which may be mountains or
other structures.
The launch period for Magellan extends from April 28 to May 23,
with windows lasting from 5 minutes at the start to about 90 minutes
on May 10. The launch period can be extended by 4 days, if necessary,
but with some degradation in mission performance.
Science and Mission Design Manager Sam Dallas of JPL said the
trajectory will be tailored so Magellan arrives at Venus on Aug. 10,
1990, regardless of launch date.
The coast to Venus will take 14 months instead of the normal 4
months because the relative positions of Earth and Venus are not
correct until October 1989, a launch slot allocated to Galileo which
is going to Jupiter by way of gravity assists at Venus and Earth. The
14-month trajectory--which will graze the orbits of Venus and Earth in
making one-and-a-half circuits of the Sun--is a compromise to avoid
delaying launch even more. However, Dallas said that if Magellan is
delayed past this launch window, it will be held in readiness in case
something happens to Galileo. The next opportunity is May 1991.
Upon arrival at Venus the spacecraft will be inserted into a
near-polar, 3-hour orbit by a solid rocket motor similar to the PAM-D
upper stages that boost communications satellites from the Shuttle.
Charlie Brown, Magellan director for Martin Marietta, said that the
rocket's line of thrust and the spacecraft center-of-gravity must be
aligned within 2.5 mm to prevent tumbling when the solid fires.
The first 18 days in orbit will be spent in calibration and other
tests. The primary mission will then commence and last 243 Earth days.
This is one Venusian day, during which the entire planet will rotate
under the spacecraft. As a cost-saving measure, the high-gain antenna
serves as both synthetic aperture radar, around periapsis (250 km),
and a data link to Earth, around apoapsis (8,000 km). Pointing will be
handled by reaction wheels with Voyager-type hydrazine thrusters
unloading them periodically.
Because most of the interesting highlands features are located in
the northern hemisphere, the periapsis is at 10 deg. latitude. This
will provide highest resolution (160 meters) in the mid-latitude
highlands, and lowest (250 meters) near the poles. The south polar
region will not be covered at all during the primary mission, and a
north-south swath (28 degrees wide) will be lost during superior
conjunction when Earth, Sun, and Venus are almost lined up.
The primary mission is to end on April 28, 1991. Mapping the
missing regions will be attempted during the extended mission, along
with the gravimetric mission. The latter requires that the high-gain
antenna be transmitting to Earth at periapsis (rather than mapping) so
that variations in orbital velocity can be measured to analyze mass
changes in the surface. Saunders said there is enough hydrazine aboard
the spacecraft to perform 4 or 5 mapping cycles in an extended mission.
The spacecraft is assembled (except for the orbit insertion motor)
and sitting in Kennedy's SAEF-2 clean-room facility. Reporters who
visited the clean room after the press briefing were told not to wear
hairspray or makeup to prevent contamination of the spacecraft.
Shortly after it arrived at Kennedy on Oct. 7 a battery was shorted
and caused a small fire.
"We have recovered from that gracefully and without scars--except
scars to our egos", Brown said. Two all-up spacecraft tests have been
performed and another is to be conducted presently. After that the
weight and c.g. tests will be performed and updated radar system
components installed. Then it will be taken to the Vertical Processing
Facility for mating to the Inertial Upper Stage on Feb. 10, and be
transported to the launch pad on March 14. This portion of the launch
flow will resemble that of the Tracking and Data Relay Satellites. At
the launch pad a final end-to-end verification test will be run before
the Shuttle arrives and the payload is installed.
"We feel the chances of getting off on April 28 are good, even
with the small window", said Kennedy Payloads Director John Conway.
|
| 456.12 | More problems with MAGELLAN | MTWAIN::KLAES | N = R*fgfpneflfifaL | Tue Feb 28 1989 14:09 | 17 |
| Date: Mon, 27 Feb 89 07:22:57 PST
From: jordankatz@cdp.UUCP
Subject: NSS Hotline Update 2/24/89
This is the National Space Society's Space Hotline for the Week
ending 2/24/89.
A faulty electrical power supply was found in the Magellan Venus
radar mapper booster, last Wed. This was another small but
frustrating problem that technicians say have been slowing down
preparation of the probe for its April 28 launch. The IUS will
probably have to be disconnected from the spacecraft in order to
replace the burnt out component. NASA must launch the probe during
the April 28 to May 28 launch window, or wait two years before the
planets return to closer positions. The launch is still scheduled for
April 28.
|
| 456.13 | Details of the MAGELLAN mission to Venus | MTWAIN::KLAES | N = R*fgfpneflfifaL | Fri Mar 31 1989 13:14 | 57 |
| The following is excerpted from NASA Activities, February 1989,
Volume 20, #2:
Magellan: Exploring Venus as Never Before
-----------------------------------------
Scheduled for launch April 28, 1989, aboard Space Shuttle
Atlantis, the spacecraft Magellan will conduct the most comprehensive
observation of the surface and gravitational features of Venus ever
undertaken. During its 243-day (one Venus rotation) primary mission,
the spacecraft will map up to 90% of the planet with high-resolution
imaging radar.
Magellan's high-resolution radar will reveal surface features as
small as 273 to 377 yards [by curious coincidence, these figures just
happen to be close to 250 to 345 meters...]. This performance exceeds
that of all previous U.S. and Soviet missions to the sister planet.
After launch from the Shuttle, Magellan will be propelled onto its
Venus trajectory by an Inertial Upper Stage, two-stage booster rocket.
Once away from the gravitational pull of Earth, the spacecraft will
cruise for 15 months (1.5 orbits of the Sun) before reaching its
destination.
Magellan is a 7,826-pound, three-axis-stabilized craft. Solar
panels and three gyroscopic momentum wheels will provide energy and
control the motion of the spacecraft.
Onboard electrical power will be supplied by the two solar panels,
totalling 15.1 square yards. The array will always be pointed towards
the Sun, despite the changing Earth-Sun-spacecraft geometry during the
mission, and will be capable of producing 1,029 watts during the
mapping phase. Two nickel-cadmium batteries will provide power during
times of solar occultation and allow normal spacecraft operations
independent of solar illumination.
With conventional radar, the resolution of an image depends on
antenna size: the bigger the antenna, the better the resolution. A
large antenna on a spacecraft, however, would be expensive and
difficult to manipulate. To solve this problem, Magellan's synthetic
aperture radar (SAR) will create high-resolution radar images by using
computer processing on Earth to simulate a large antenna on the
spacecraft. The onboard radar system will operate as though it has a
huge antenna, hundreds of yards long, when the antenna is actually 12
feet in diameter.
During the 37.2-minute data acquisition phase of each orbit, the
SAR will transmit several thousand pulses of radio energy each second.
The pulses will illuminate a 15.5-mile-wide swath of the planet's surface.
Magellan's orientation will be carefully controlled by three
momentum wheels, assisted, when necessary, by 12 small gas-thruster
motors. Magellan is managed by NASA's Jet Propulsion Laboratory,
Pasadena, California.
Peter Scott (pjs@grouch.jpl.nasa.gov)
|
| 456.14 | MAGELLAN Update - April 3 | MTWAIN::KLAES | N = R*fgfpneflfifaL | Thu Apr 06 1989 16:54 | 44 |
| Payload Status Report
Kennedy Space Center
Monday, April 3, 1989
George Diller
Magellan (IUS-18)
The Magellan spacecraft with the attached Inertial Upper
Stage Booster was loaded into the payload bay of the Space
Shuttle Atlantis on March 25. Establishment of electrical
connections was completed on March 29. The Interface
Verification Test (IVT) to verify those connections will be done
this Tuesday, Apr. 4. Astronauts Mark Lee and Mary Cleave will
be on the flight deck of the Space Shuttle Atlantis participating
in this exercise.
The End-to-End test will also be performed later this week
on Saturday, Apr. 8. This exercise will verify the ability of
payload ground stations to receive data and send commands to
IUS/Magellan via the communications systems of the orbiter.
Participating in the test will be the Jet Propulsion
Laboratory in Pasadena, Ca., the Deep Space Network facilities at
Goldstone, Ca. and the MIL-71 station at KSC, the IUS facilities
of the Consolidated Space Test Center at Sunnyvale, Ca., Mission
Control at the Johnson Space Center in Houston, and the Magellan
spacecraft ground control station at Hangar AO on Cape Canaveral
Air Force Station.
On Thursday, March 30, the Magellan Test Team completed a
Joint Integrated Simulation (JIS). Participating were many of
same team members who will be be involved in the End-to-End test
on Saturday. Also, all five STS-30 astronauts participated in
the JIS from the Space Shuttle flight simulator at JSC.
This is a problem solving simulation for the test team where
surprises are introduced for an immediate response and a
solution. This particular exercise invoked challenges ranging a
complete power failure at Magellan's ground control station at
KSC, to an earthquake at JPL in Pasadena. The goal for the team
is to deploy the spacecraft from Atlantis successfully despite
worst case hypotheticals.
|
| 456.15 | Potential software problem on MAGELLAN | DOCO2::KLAES | N = R*fgfpneflfifaL | Mon Apr 24 1989 13:31 | 16 |
| VNS COMPUTER NEWS: [Tracy Talcott, VNS Computer Desk]
================== [Nashua, NH, USA ]
Software - Scientists catch flaw in Magellan spacecraft destined for Venus
The danger - though a remote one - was that if the robot craft lost its
proper orientation to the Sun and Earth, the computerized control system
might, under some circumstances, fail to right the probe. A 21 word patch is
being tested 24 hours a day at the Martin Marietta facility, said Tony Spear,
deputy project manager for the Magellan. "We want to stress the software" to
make sure it works.
{The Boston Globe, 23-Apr-89, p. 70}
<><><><><><><> VNS Edition : 1803 Monday 24-Apr-1989 <><><><><><><>
|
| 456.16 | MAGELLAN and beyond | DOCO2::KLAES | N = R*fgfpneflfifaL | Sun Apr 30 1989 17:18 | 82 |
| From: yee@trident.arc.nasa.gov (Peter E. Yee)
Newsgroups: sci.space
Subject: U.S. launches most ambitious space science period (Forwarded)
Date: 26 Apr 89 21:59:27 GMT
Reply-To: yee@trident.arc.nasa.gov (Peter E. Yee)
Graciela Iguina
Headquarters, Washington, D.C. April 26, 1989
RELEASE: 89-63
U.S. LAUNCHES MOST AMBITIOUS SPACE SCIENCE PERIOD
America's planetary exploration program, which almost became an
"also ran," will reassume world leadership with the launch of the
Magellan spacecraft to Venus, the head of NASA's space science program
said today.
Dr. Lennard A. Fisk said the Magellan launch on Friday [now
Monday at the earliest] will mark the beginning of a "new golden age
of space science" with 36 major missions in the next 5 years. "If we
are smart, we will use these missions to conduct the biggest and the most
public science and engineering lesson ever for the youth of this nation."
"There is no task more important for a government than to instill
in its people the conviction that the future will be brighter than the
present," Fisk said. While conceding that there are national defense
and poverty problems in this country, Fisk stated that funds have been
committed for these activities and that "somewhere among these
expenditures that are based on fear and on injustice, there also
should be expenditures based on hope for a brighter tomorrow."
Fisk said that the United States is again the leader in planetary
exploration and "we are determined that never again will this
leadership be allowed to pass from us."
Two days from now, the Shuttle Atlantis will lift off from
Kennedy Space Center, carrying the Magellan space probe destined for
Venus. "The Magellan mission alone will return more data than all
previous planetary mission combined."
Fisk made these and other points:
o Magellan will map the surface of Venus with a radar that has 10
times the resolution of any previous U.S. or Soviet mission.
Magellan will cover 90 percent of the planet as opposed to only
25 percent by the last Soviet mission and should answer the fundamental
question of why Venus -- which is so similar to Earth in size and location
-- is so different.
o NASA will complete the Hubble Space Telescope, the Gamma Ray
Observatory, the Advanced X-Ray Astrophysics Facility and the Space
Infrared Astrophysics Facility. These four great observatories,
spanning the electromagnetic spectrum from infrared to gamma rays,
possess resolution and sensitivity never before possible in astronomy.
o The Cosmic Backround Explorer this summer will probe the
backround radiation left over from the birth of the Universe -- the
big bang.
o The Astro Spacelab mission, next year, will make definitive
measurements of the recent Supernova 1987A -- the closest observable
supernova in 400 years.
o Ulysses will examine the poles of the Sun, the Upper
Atmospheric Research Satellite will study Earth's atmosphere, Mars
Observer exploration will follow in 1992, and Galileo will explore
Jupiter and its moons in 1996. There are also plans for the Cassini
probe to Saturn in 1997.
o The Earth Observing System (EOS) will study our planet from the
polar platforms of Space Station Freedom, making continuous and
comprehensive measurements of Earth and what humans are doing to it.
EOS "will serve as a basis for sound policy decisions to protect the
future of our planet...a graphic demonstration of American technology
in space serving the peoples of the world."
"We need to appreciate," Fisk said, "that with all these
activities and plans, we are sending a simple but very powerful
message -- that we are a nation that believes in its future."
|
| 456.17 | MAGELLAN Status Report for May 18, 1989 | RENOIR::KLAES | N = R*fgfpneflfifaL | Thu May 18 1989 22:19 | 37 |
| Newsgroups: sci.space
Subject: Magellan Status for 05/18/89 (Forwarded)
Date: 18 May 89 20:47:42 GMT
Reply-To: yee@trident.arc.nasa.gov (Peter E. Yee)
Organization: NASA Ames Research Center, Moffett Field, CA
MAGELLAN STATUS
May 18, 1989
Twice daily momentum wheel desaturations were performed as
expected Wednesday at 00:45 a.m. and 12:45 p.m. PDT. The daily star
calibration was at 1 p.m. PDT and was performed without difficulty.
Both stars were detected and a full attitude update was obtained. The
problem experienced Tuesday did not recur, but investigation continues
into why the spacecraft lost the star.
Analysis of stored Launch Phase telemetry played back last Friday
and Saturday indicates the spacecraft's solar panels were latched
after the start of the first IUS burn. It would appear that the burn
acceleration did contribute to the final latch of the panels, the
project said today.
The Cruise-2 computer command sequence which contains Sunday's
Trajectory Correction Maneuver (TCM-1) is being tested at the System
Verifications Lab (SVL). But the command data system breadboard was
giving some difficulty which could delay completion of the test prior
to the Cruise-2 upload Saturday. Project said the problem is receiving
a lot of attention.
SPACECRAFT
Distance From Earth (mi) 2,082,381.58
Velocity Geocentric 5,936.59 mph
Heliocentric 59,952.74 mph
Round Trip Light Time 11.1 sec
|
| 456.18 | MAGELLAN Status - May 19 | RENOIR::KLAES | N = R*fgfpneflfifaL | Fri May 19 1989 20:28 | 39 |
| Newsgroups: sci.space
Subject: Magellan Status for 05/19/89 (Forwarded)
Date: 19 May 89 18:33:11 GMT
Sender: usenet@ames.arc.nasa.gov
Reply-To: yee@trident.arc.nasa.gov (Peter E. Yee)
Organization: NASA Ames Research Center, Moffett Field, CA
MAGELLAN STATUS
May 19, 1989
Daily momentum wheel desaturations continue as scheduled, twice
daily, 00:45 a.m. and 12:45 p.m. PDT, project said today. The daily
star calibration also was performed without difficulty. Both stars
were detected and a full attitude update was obtained.
The temperatures of Rocket Engine Modules 3 and 4 continue to
slowly cool as the celestial geometry gradually changes. They are
running a steady 56-58 C (132.8-136.4 F) except during wheel
desaturations when they warm up into the 60s C (140-156 F), still
considerably below the design limit of 83 C (181.4 F).
The Command Data System breadboard began working again in the
System Verification Lab and the test of Cruise)2 computer command
sequence, which holds the upcoming Trajectory Correction Maneuver, is
going well and nearing completion. Project will be prepared to upload
the sequence Saturday.
A meeting today was scheduled to address solution options to the
three current problems: 1) Rocket Engine Module temperatures; 2) star
rejects during star calibrations; and 3) desaturation frequency.
SPACECRAFT Distance From Earth (miles)
2,220,474
Velocity Geocentric 5,905 mph
Heliocentric 59,970 mph
Round Trip Light Time 12.2 sec
|
| 456.19 | MAGELLAN Status - May 22-24 | RENOIR::KLAES | N = R*fgfpneflfifaL | Thu May 25 1989 12:32 | 95 |
| Newsgroups: sci.space
Subject: Magellan Status for 05/22/89 (Forwarded)
Date: 25 May 89 05:28:17 GMT
Reply-To: yee@trident.arc.nasa.gov (Peter E. Yee)
Organization: NASA Ames Research Center, Moffett Field, CA
[I was on travel the past few days, hence the late postings. - PEY]
MAGELLAN STATUS
May 22, 1989
Twice daily momentum wheel desaturations were performed with
nominal results Friday, Saturday and Sunday. Daily star calibrations
also were performed and both stars, Alpha Boots and Gamma Crux, were
detected and a full attitude update was obtained.
The flight team has been authorized to implement a plan to
alternate use of the high-gain and medium-gain antennas at different
attitudes to collect rocket engine module (REM) temperature data over
a period between days 150 and 190. The information is expected to help
in developing a solution to the anticipated overheating of the REMs
when the spacecraft moves closer to the Sun.
On Saturday, the Cruise-2 sequence was uploaded to the spacecraft.
It included the trajectory correction maneuver commands for Sunday's
rocket burn which project said was "to perfection." Cruise-2 also will
provide commands for the next 12 days.
SPACECRAFT
Distance From Earth (mi) 2,642,052
Velocity Geocentric 5,802 mph
Heliocentric 60,057 mph
Round Trip Light Time 14.1 sec
Newsgroups: sci.space
Subject: Magellan Status for 05/23/89 (Forwarded)
Date: 25 May 89 05:29:03 GMT
Reply-To: yee@trident.arc.nasa.gov (Peter E. Yee)
Organization: NASA Ames Research Center, Moffett Field, CA
MAGELLAN STATUS
May 23, 1989
All Magellan spacecraft systems were working well today. The
Navigation Team continued to refine its estimate of the accuracy of
the Trajectory Correction Maneuver (TCM) Sunday which appears to be
extremely precise.
Twice daily momentum wheel desaturations and the daily star
calibration were performed as expected.
The X-band was turned on Monday afternoon and the spacecraft
maneuvered to point the high-gain antenna to Earth for 10 hours of
activity. Just before midnight (PDT) the spacecraft was turned to
again aim the medium-gain antenna at Earth.
The first very long baseline interferometry (VLBI) measurements
were taken Monday using 34-meter DSN stations at Goldstone and Madrid.
Also, engineering telemetry recorded during the TCM Sunday night was
successfully played back at 115.2 kilobits per second to Goldstone and
relayed to JPL.
SPACECRAFT
Distance From Earth (mi) 2,780,923
Velocity Geocentric 5,770 mph
Heliocentric 60,091 mph
Round Trip Light Time 14.9 sec
Newsgroups: sci.space
Subject: Magellan Status for 05/24/89 (Forwarded)
Date: 25 May 89 05:30:14 GMT
Reply-To: yee@trident.arc.nasa.gov (Peter E. Yee)
Organization: NASA Ames Research Center, Moffett Field, CA
MAGELLAN STATUS
May 24, 1989
The twice daily momentum wheel desaturations and the daily star
calibration were performed as expected.
Analysis of stored trajectory correction maneuver (TCM) data confirmed
the burn last Sunday was every bit as successful as first indicated.
SPACECRAFT
Distance From Earth (mi) 2,919,025
Velocity Geocentric 5,738 mph
Heliocentric 60,128 mph
One Way Light Time 15 sec
|
| 456.20 | | MEMIT::SCOLARO | Fusion in a Glass! | Thu May 25 1989 14:17 | 9 |
| Can someone who knows tell me/us what a:
"twice daily momentum wheel desaturations"
is?
Thanks in advance,
Tony
|
| 456.21 | Desaturation | HAZEL::LEPAGE | Life is a tale told by an idiot | Thu May 25 1989 14:38 | 20 |
| Re: -1
The Magellan spacecraft uses fly wheels for most of its attitude
control (as opposed to small attitude "jets"). When the spacecraft
starts to drift for some reason (out gassing, minute fuel leaks,
even light pressure) or even for major attitude changes, angular
momentum can be transfered from the fly wheels to the spacecraft
to correct for drift or make attitude changes.
Normally the angular momentum in a set of attitude changes will
be conserved but because of friction in the flywheels or outside
torques on the spacecraft, the fly wheels will tend to slow down
or speed up too much. Periodicly the fly wheels are brought back
to their proper speed or are "desaturated". The torques produced
in this "desaturation" are compensated by the use of the attitude
control jets. Overall, this system of using flywheels for most
maneuvers and the attitude control jets for major maneuvers and
flywheel "desaturation" saves hydrazine fuel and lengthens the mission.
Drew
|
| 456.22 | | STAR::HUGHES | | Thu May 25 1989 16:12 | 9 |
| Yup. Solar wind and gravity effects on the trajectory are amongst the
major causes too.
For periodic effects, careful planning can sometimes allow
complementary attitude changes to desaturate the momentum wheels, i.e.
you use the momentum stored by one manouver to perform a later
complementary manouver.
gary
|
| 456.23 | | LILAC::MKPROJ | REAGAN::ZORE I'm the NRA | Thu May 25 1989 20:08 | 4 |
| Clever little engineers these humans, huh Tony? You beat me to the punch on
asking that question! :-)
Rich
|
| 456.24 | MAGELLAN Status - May 25 | RENOIR::KLAES | N = R*fgfpneflfifaL | Fri May 26 1989 19:33 | 39 |
| Newsgroups: sci.space
Subject: Magellan Status for 05/25/89 (Forwarded)
Date: 25 May 89 23:13:01 GMT
Reply-To: yee@trident.arc.nasa.gov (Peter E. Yee)
Organization: NASA Ames Research Center, Moffett Field, CA
MAGELLAN STATUS
May 25, 1989
Plans are being made to place in Magellan's Cruise 4 and 5
computer command sequences information to help develop a solution to
the rocket engine module overheating problem. Starting with Cruise-4,
which will be uploaded on June 9, the spacecraft will be turned 180
degrees around an axis through the medium-gain antenna (MGA) to
collect thermal data in a new attitude.
Also, two new stars will be added to the star calibration
sequence in Cruise-4. The spacecraft will scan the stars of a
different spectral class to assist in adjusting the star-scanner
acceptance criteria and on-board attitude determination. Those scans
will not be updated, however.
The twice daily momentum wheel desaturations and the daily star
calibration were performed routinely Wednesday.
Project has determined the time of day Magellan will reach its
aim point at Venus on August 10, 1990. Without further trajectory
correction it would be 10:30 a.m. PDT. Another trajectory correction
maneuver scheduled for December, however, will skew that time by
several minutes.
SPACECRAFT
Distance From Earth (mi) 3,056,363
Velocity Geocentric 5,706 mph
Heliocentric 60,169 mph
One Way Light Time 15.2 sec
|
| 456.25 | Geocentric/Haliocentric? | HPSRAD::DZEKEVICH | | Fri May 26 1989 19:49 | 6 |
| What is geocentric and haliocentric? Is one referenced from Earth
and the other from somewhere else or point to point speed vs orbit
speed?
Joe
|
| 456.26 | geo versus heleo | SAUTER::SAUTER | John Sauter | Fri May 26 1989 20:01 | 11 |
| Geocentric means relative to Earth. Heleocentric means relative to the
Sun. Notice the spacecraft is slowing down relative to Earth and
speeding up relative to the Sun. The Earth's gravity slows it as it
pulls away, and the Sun's gravity speeds it up as it falls towards the
Sun. When it is captured by Venus, the situation will become more
complex.
By the way, the light time was originally labelled as "round trip", but
is now listed as "one way", without a major change in the time.
According to my arithmetic, the "one way" label is more nearly correct.
John Sauter
|
| 456.27 | Strange window | BRSSWS::PIGEON | Atlantis-Watcher | Mon May 29 1989 09:27 | 17 |
| one question.
On may 4, when Atlantis/Magellan was launched, it was said that because
the mission was interplanetary, there was a launch window of 64 minutes
only starting from 13.58 to 15.02 EDT.
Now I understand the notion of a launch window for interplanetary
flights, depending on the relative position of the planets. That window
last for weeks at least. The launch from earth orbit to sun orbit
should happen within in order to achieve a low energy transfer.
What I don't understand is the need of a launch window for getting on
earth orbit. To me it seems that just any time would do.
Gurus, the floor is yours...
|
| 456.28 | | PRAGMA::GRIFFIN | Dave Griffin | Tue May 30 1989 01:11 | 9 |
| I'll take the latter half of the window. The window closes around
3PM for *any* launch, not just this one. It has to do with the
availability of daylight at the emergency landing sites in Spain
(and possibly another alternate).
If there is a "orbital mechanics" reason for the rest of the window,
it evades me too (other than ground support timing).
- dave
|
| 456.29 | lots of constraints | SAUTER::SAUTER | John Sauter | Tue May 30 1989 13:38 | 15 |
| There are a lot of constraints on the operation of the shuttle, and I
don't pretend to know them all. However, in addition to the desire for
daylight at the emergency landing site, consider that the
interplanetary probe must be launched at the correct point in the
shuttle's orbit, so that it will head towards Venus and not in some
other direction. That requires that the shuttle be up long enough to
perform the pre-deployment activities. In some cases there are limits
to how long the probe can stay cooped up in the cargo bay without its
inertial navigator being updated, though I doubt this applies to
Magellan. There may also be shuttle limitations on holding the probe
in the cargo bay---maneuvering requires more fuel if you have to carry
the Magellan along, so they may want to launch it as early as possible
in order to do other experiments. (Actually, I am somewhat surprised
that there is any launch window at all---good planning, I guess).
John Sauter
|
| 456.30 | Another WAG | DECWIN::FISHER | Burns Fisher 381-1466, ZKO3-4/W23 | Tue May 30 1989 15:53 | 11 |
| I can imagine (although I don't *know*) that there is some relationship that
has to be met with regard to the probe being at the correct lattitude
over the earth (e.g. crossing the equator or crossing the ecliptic plane or
some such) while at the same time being in the right location relative to
the earth/sun configuration. Each of these conditions could be met at least
once during almost any orbit, but I suspect that varying the launch time
would vary the phase of the two events differently. Thus you adjust the
launch time to get the two events to happen simultaneously within some
tolerence.
Burns
|
| 456.31 | | STAR::HUGHES | | Tue May 30 1989 17:45 | 32 |
| This mission required very precise control of orbit inclination, so
that the IUS/Magellan stack was released at the correct point in space
with the desired amount of N-S velocity for the trajectory programmed
into the IUS' guidance computer (basically what Burns said in .30)
It is either undesirable or impossible to update the IUS computer in
real time. The shuttle had to bear the complexity of being exactly
where it was supposed to, even to the extent of performing a series of
manouvers with automatic station keeping disabled, reading the results
back from the IUS computer and adjusting the shuttle's guidance state
vectors to compensate for any shifting that may have occured in the IUS
support equipment in the cargo bay. I also got the impression that the
precision required was more or less at the limit of IUS capabilities
and that the launch cradle had been found toshift on previous missions.
Without this constraint, the planetary launch window would have been
much wider.
The other factor that restricted launch windows was the requirement to
deploy the IUS/Magellan stack in daylight over the Indian ocean to
ensure telemetry coverage (via TDRS?), optical tracking from aircraft
before/during first stage burn and spacecraft power from it's solar
arrays.
While in the payload bay, the IUS/Magellan stack was on shuttle power,
until the launch cradle was fully deployed. You may have noticed that
an IUS mission typically involves elevating the launch cradle about
half way while payload tests are under way. The IUS and payload switch
to internal power when (or just before) the launch cradle is fully
elevated.
gary
|
| 456.32 | MAGELLAN Status - May 26 | RENOIR::KLAES | N = R*fgfpneflfifaL | Tue May 30 1989 17:52 | 32 |
| Newsgroups: sci.space
Subject: Magellan Status of 05/26/89 (Forwarded)
Date: 26 May 89 22:27:03 GMT
Reply-To: yee@trident.arc.nasa.gov (Peter E. Yee)
Organization: NASA Ames Research Center, Moffett Field, CA
MAGELLAN STATUS
May 26, 1989
After today, the Magellan status reports will be available only
once a week, unless warranted by spacecraft activity.
The twice daily momentum wheel desaturations and the daily star
calibration were performed routinely Thursday.
Analysis of last Sunday's trajectory correction maneuver indicates
an achieved velocity of 2.967 meters per second, versus a desired 2.935
meters per second. The execution error was less than 1.1 percent.
The final spacecraft parameters for Cruise-3, the next spacecraft
computer command sequence, have been given to the spacecraft team's
Upload Preparation Group. Cruise-3 will be uploaded next Tuesday
afternoon, May 30.
SPACECRAFT
Distance From Earth (mi) 3,192,936
Velocity Geocentric 5,674 mph
Heliocentric 60,213 mph
One Way Light Time 17.5 sec
|
| 456.33 | MAGELLAN Weekly Status - May 30-June 3 | RENOIR::KLAES | N = R*fgfpneflfifaL | Wed May 31 1989 14:20 | 37 |
| Newsgroups: sci.space
Subject: Magellan Status for 05/30/89 - 06/03/89 (Forwarded)
Date: 30 May 89 22:04:37 GMT
Reply-To: yee@trident.arc.nasa.gov (Peter E. Yee)
Organization: NASA Ames Research Center, Moffett Field, CA
MAGELLAN WEEKLY STATUS
May 30-June 3, 1989
This is a weekly status report. The next report will be issued June 5.
The spacecraft is in good health following the long holiday
weekend. All momentum wheel desaturations and star calibrations were
performed routinely.
The Attitude Control team determined on May 27 that a ground
software error was responsible for an attitude update problem and the
error is being corrected. No flight software changes are required, but
gain changes will be uploaded.
The Cruise-3 computer command sequence was successfully tested in
the System Verification Lab and is to be uploaded this afternoon.
Cruise-3 contains wheel desaturations at 12:45 p.m. and 12:45
a.m. and the star calibration at 1 p.m. daily. It also contains radio
tests and arming of the Solid Rocket Motor on June 7 at 3 p.m. Arming
is done early so that any possible problems later in the cruise will
not prevent its arming.
SPACECRAFT
Distance From Earth (mi) 3,735,101
Velocity Geocentric 5,531 mph
Heliocentric 60,293 mph
One Way Light Time 20.0 sec
|
| 456.34 | MAGELLAN Status - June 6 | RENOIR::KLAES | N = R*fgfpneflfifaL | Tue Jun 06 1989 22:17 | 61 |
| Newsgroups: sci.space
Subject: Magellan Status for week of 06/06/89 (Forwarded)
Date: 6 Jun 89 17:26:46 GMT
Reply-To: yee@trident.arc.nasa.gov (Peter E. Yee)
Organization: NASA Ames Research Center, Moffett Field, CA
MAGELLAN WEEKLY STATUS
June 6
This is a weekly status report. The next report will be issued June 12.
The spacecraft continues to operate routinely with twice daily
momentum wheel desaturations and once-a-day star calibrations.
Radio calibration tests will begin this month.
Magellan engineers are periodically rolling the spacecraft 180
degrees about the Medium-Gain Antenna axis to obtain Rocket Engine
Module (REM) temperature data to update the temperature model. Again,
the higher than expected REM temperatures will constrain use of the
High-Gain Antenna and, consequently, the Deep Space Network's Very
Long Baseline Interferometry (VLBI) tests during the cruise. While
this is not considered to be a major problem, REM temperatures could
constrain mapping operations in the first cycle of an extended mission.
Corrections to ground attitude control software have been made
which are believed to have solved an attitude knowledge problem.
Updates will be added to the flight attitude software on Friday, June
9. One possible result of the attitude control problem is mispointing
the High-Gain Antenna on the order of one-half a degree, which
results in a small loss in the downlink signal. The loss is not a
problem at the present time because there is more than adequate margin
in the receiving antenna. Once the attitude control knowledge problem
is solved and the subsystem calibrated, a High-Gain Antenna calibration
will be made to take out any mechanical or electrical offset.
A technical briefing is scheduled for June 13 on the attitude
control knowledge problem and whether to continue momentum wheel
desaturations twice a day.
The Solid Rocket Motor (SRM) temperature is at 31 degrees C (87.8
F), close to the redline limit of 33 C (91.4 F) as the nozzle points
closer to the Sun. This is being watched closely.
Magellan has moved inward from Earth's orbit toward the Sun.
Magellan was fired by the IUS in the opposite direction to Earth's
flight to slow the spacecraft down so it would fall inward toward the
orbit of Venus. In July the spacecraft will begin to speed up relative
to Earth and about August 1 it will have caught up with Earth so that
the Sun, spacecraft, and Earth will be almost in a straight line. At
about noon of each day, if you could see Magellan, it would be
overhead with the Sun in the background.
SPACECRAFT
Distance From Earth (mi) 4,502,212
Velocity Geocentric 5,291 mph
Heliocentric 60,719 mph
One Way Light Time 24.2 sec
|
| 456.35 | Just like slapping the TV set | RENOIR::KLAES | N = R*fgfpneflfifaL | Sun Jun 11 1989 19:36 | 20 |
| From: PJS@GROUCH.JPL.NASA.GOV (Peter Scott)
Newsgroups: sci.space
Subject: Magellan
Date: 6 Jun 89 18:08:02 GMT
Organization: The Internet
From an in-house Magellan bulletin:
"The only troblem that occurred during the launch phase was the
failure of the Magellan solar panels to lock in place prior to the IUS
burns. Again this potential problem had been anticipated and was
easily corrected by rotating the solar panels to an orientation that
caused lockup during the IUS burns. Shortly thereafter the solar
panels were rotated to acquire the Sun and are providing power to the
spacecraft at approximately the expected levels."
In other words, if something sticks, give it a kick.
Peter Scott (pjs@grouch.jpl.nasa.gov)
|
| 456.36 | MAGELLAN Status - June 13 | RENOIR::KLAES | N = R*fgfpneflfifaL | Wed Jun 14 1989 21:07 | 48 |
| Newsgroups: sci.space
Subject: Magellan Status for week of 06/13/89 (Forwarded)
Date: 13 Jun 89 21:43:50 GMT
Reply-To: yee@trident.arc.nasa.gov (Peter E. Yee)
Organization: NASA Ames Research Center, Moffett Field, CA
MAGELLAN WEEKLY STATUS
June 13
This is a weekly status report. The spacecraft continues successful
operation with twice daily momentum wheel desaturations and once-a-day
star calibrations.
The Solid Rocket Motor was armed on June 5 to avoid any later
cruise problem that would preclude the arming.
Several characterization tests were conducted during the past
week to define the telecommunications link between the spacecraft
Radio Frequency Subsystem (RFS) and the Deep Space Network. Static
Phase Error Tests were performed Monday and Thursday to determine the
spacecraft receiver's rest frequency. An S-band test also was
conducted Wednesday and will be repeated Friday. After some minor
lock-up problems, the tests were satisfactorily completed.
Cruise loads 4 and 4A were tested through the System Verification
Lab and were transmitted June 9.
The Rocket Engine Modules (REMs), while well below upper
temperature limits now, will get warmer as the spacecraft draws closer
to the sun and will restrict use of the High-Gain Antenna, and the
Deep Space Network very long baseline interferometry tests. Martin
Marietta and JPL are formulating jointly a test plan, using spare
components, to determine the maximum safe temperature for the REMs.
The spacecraft team is analyzing another heat problem that will
drive the head-end temperature of the Solid Rocket Motor case above
the current flight limits. It is currently 32 C (89.6 F) with a
current redline limit of 38 C (100.4 F). Morton Thiokol is working
with the team to examine the limits.
SPACECRAFT
Distance From Earth (mi) 5,497,458
Velocity Geocentric 5,033 mph
Heliocentric 61,624 mph
One Way Light Time 29.5 sec
|
| 456.37 | MAGELLAN Status - June 20 | CLIPR::KLAES | N = R*fgfpneflfifaL | Wed Jun 21 1989 14:46 | 48 |
| Newsgroups: sci.space
Subject: Magellan Status for week of 06/20/89 (Forwarded)
Date: 20 Jun 89 22:29:13 GMT
Reply-To: yee@trident.arc.nasa.gov (Peter E. Yee)
Organization: NASA Ames Research Center, Moffett Field, CA
MAGELLAN WEEKLY STATUS
June 20, 1989
This is a weekly status report. Magellan continues to operate
successfully. Momentum wheel desaturations and star calibrations were
routinely performed except for Friday. On that day, the star scanner
correctly identified the first star crossing of slits 3 and 4 but saw
a pulse apparently repeated and correctly rejected that pulse. That
set the timing off and the second star crossing was not performed. On
Saturday and Sunday, however, star calibrations were routinely accomplished.
The spacecraft was rotated 180 degrees about the Medium-Gain
Antenna axis. This attitude has significantly cooled both the Rocket
Engine Modules (REMs) and the Solid Rocket Motor (SRM). It will be the
primary attitude for the next couple of weeks. Ground tests for both
thermal problems are currently being initiated and results are
expected on the SRM problem within three weeks.
On Tuesday, June 13, memory read-outs of both the Command and
Data Subsystem and the Attitude and Articulation Control System were
performed and the results compared successfully with ground-maintained
memory maps.
Also on Tuesday, the voice nets between JPL and Denver were
restored after being out of service for six days.
On Thursday, June 15, the first star calibration not used to
update the spacecraft's attitude was performed for the purpose of
calibrating star magnitude thresholds for two different stars, Alpha
Centauri and Alpha Canis Major. The calibration data, although not
used to update the spacecraft's attitude, was assessed on the ground
and indicated lower thresholds were needed. Another, similar,
calibration was performed successfully on Saturday.
SPACECRAFT
Distance From Earth (mi) 6,324,124
Velocity Geocentric 5,064 mph
Heliocentric 62,493 mph
One Way Light Time 33.3 sec
|
| 456.38 | MAGELLAN Status - June 26 | RENOIR::KLAES | N = R*fgfpneflfifaL | Tue Jun 27 1989 15:02 | 59 |
| Newsgroups: sci.space
Subject: Magellan Status for 06/26/89 (Forwarded)
Date: 26 Jun 89 23:53:54 GMT
Reply-To: yee@trident.arc.nasa.gov (Peter E. Yee)
Organization: NASA Ames Research Center, Moffett Field, CA
MAGELLAN WEEKLY STATUS
June 26, 1989
This is a weekly status report. The Magellan spacecraft went
through successful momentum wheel desaturations on a daily basis.
Of the seven star scans to update the attitude from Friday June
16 to Thursday June 22, four were fully successful on both stars and
three were partially successful, rejecting one of two stars in each
case. On each of three days the star scanner detected a spurious pulse
from one of the two stars. The flight software correctly rejected the
pulse, but also rejected the measurement because the timing was then
off. Only a two-axis attitude update was obtained in each case. The
problem appears to be related to spacecraft attitude, since these
events occurred after the turn to alternate medium-gain antenna
attitude June 12.
A second star calibration was performed Saturday to get acceptable
magnitude thresholds for two new stars, Alpha Centauri and Sirius. The
selected magnitudes were acceptable, but Sirius may be too bright and
too blue to be a reliable guide star, and data analysis is continuing.
The good news concerning star scans is that the on-board bias
estimation process was enabled last Monday and after two consecutive
good scans the following two days, the process was verified as
functioning perfectly. It is so stable, mission operators said, that
they could miss every other star scan, or even several in a row, and
not lose track of Magellan's attitude. Further adjustments are being
considered to make the flight system even more immune to interruption
by spurious pulses.
The spacecraft's current attitude is keeping the Solid Rocket
Motor (SRM) and the Rocket Engine Modules (REMs) cool. But they are
expected to warm up again when the High-Gain antenna is again turned
toward Earth on day 181. Tests are in progress at Morton Thiokol on
SRM fuel samples to determine the actual upper temperature limits and
tests results are expected by July 7. Also, Martin Marietta in Denver
is working with JPL on tests to determine upper temperature limits of
the flight REMs.
The final command sequence of Cruise 5 was completed and sent to
the systems verification lab for testing. An error was found in the
flight software and corrected with a one-word patch and the sequence
was uploaded last Saturday.
SPACECRAFT
Distance From Earth (mi) 7,039,205
Velocity Geocentric 5,393 mph
Heliocentric 63,381 mph
One Way Light Time 37.8 sec
|
| 456.39 | MAGELLAN Status - July 11 | RENOIR::KLAES | N = R*fgfpneflfifaL | Mon Jul 17 1989 16:50 | 48 |
| Newsgroups: sci.space
Subject: Magellan Status for 07/11/89 (Forwarded)
Date: 15 Jul 89 06:33:21 GMT
Reply-To: yee@trident.arc.nasa.gov (Peter E. Yee)
Organization: NASA Ames Research Center, Moffett Field, CA
MAGELLAN WEEKLY STATUS
July 11, 1989
This is a weekly status report. The Magellan spacecraft is
operating well but has had some problem with glitches during star
calibrations which have prevented updates in attitude knowledge.
Still, attitude drift is small and the mission operations team said
the spacecraft can go at least five days without a star calibration
update. So far, only two days in a row have been missed. The cause of
the glitches is being studied.
The team is studying ways to eliminate the problem through
filters in the attitude control software. The glitches are described
as only an aggravation during cruise but will have to be eliminated to
a larger degree before the mapping phase begins.
High temperature readings on the Solid Rocket Motor and the
Rocket Engine Modules in some attitudes have been a problem. The
operations team said Morton Thiokol made tests with a sample of the
Solid Rocket Motor core, and believes the temperature limit can be
raised from 34 C (93.2 F), to 70 C (158 F).
Rocket Research is doing the tests on the Rocket Engine Modules,
using spares. The current upper limit is set at 77 C (170.6 F). The
tests are to see if the limit can be raised to 120 C (248 F). Both
studies will be carefully reviewed. The heating is caused by direct
sunlight when the spacecraft is in certain attitudes.
This month, Magellan will participate in Deep Space Network very
long baseline interferometry and telecon tests. It also will
accomplish star calibration with additional stars and continue
high-rate data playbacks.
SPACECRAFT
Distance From Earth (mi) 9,098,851
Velocity Geocentric 7,536 mph
Heliocentric 66,163 mph
One Way Light Time 48.0 sec
|
| 456.40 | What is the process of maintaining attitude? | ADOMV1::SHARPE | C is bliss? | Tue Jul 18 1989 04:42 | 20 |
| This may not be the right place to put this, so if not, moderator,
please feel free to move it.
Can someone please post a description of how attitude control is
maintained. From the previous notes in this topic, it seems clear
that one or two distant stars are used, but what exactly are the
details?
Questions that come to mind are:
- Are all three axes important, or is one (longest?) assumed to
be aligned to the ecliptic, or is this a stupid question?
- Are two stars enough, as long as their separation is large enough,
or are more than two required? Which ones?
- What is the process on a step by step basis?
Regards
Richard Sharpe
|
| 456.41 | MAGELLAN Status - July 17 | RENOIR::KLAES | N = R*fgfpneflfifaL | Tue Jul 18 1989 20:35 | 44 |
| Newsgroups: sci.space
Subject: Magellan Status for 07/17/89 (Forwarded)
Date: 18 Jul 89 17:54:08 GMT
Reply-To: yee@trident.arc.nasa.gov (Peter E. Yee)
Organization: NASA Ames Research Center, Moffett Field, CA
MAGELLAN WEEKLY STATUS
July 17, 1989
This is a weekly status report. The Magellan spacecraft continues
to perform twice daily momentum wheel desaturations and, for purposes
of attitude update, once daily star calibrations.
All of the desaturations were normal and seven of nine of the
star calibrations were successful. Two were interrupted and anomalies
in the star scans are being investigated.
For 15 hours on July 8 the spacecraft maneuvered to the alternate
Medium-Gain Antenna attitude to gather additional Rocket Engine Module
temperature data. The data showed that REM temperatures in August and
September should be about 87 C (188.6 F). This will require plans to
work around the problem unless ground tests now underway show the
higher temperature will be safe.
The Solid Rocket Motor upper dome temperatures are increasing
slightly each day, and prior to this report, the temperature was 30 C
(86 F). Results of tests by Morton Thiokol, received last Wednesday,
show that the upper dome temperature limits can be raised to 70 C (158 F)
for a sustained period of four weeks, or 80 C (176 F) for a period of two
weeks. After review, it is expected the higher limit will be used.
The Cruise-6 computer command sequence was uplinked Sunday and
took effect today. The uplink was attempted three times before it was
successful, and the problem was attributed to Goldstone.
SPACECRAFT
Distance From Earth (mi) 10,167,907
Velocity Geocentric 9,024 mph
Heliocentric 67,493 mph
One Way Light Time 54.6 sec
|
| 456.42 | MAGELLAN Status - July 25 | CLIPR::KLAES | N = R*fgfpneflfifaL | Wed Jul 26 1989 04:02 | 46 |
| Newsgroups: sci.space
Subject: Magellan Status for 07/25/89 (Forwarded)
Date: 25 Jul 89 22:32:27 GMT
Reply-To: yee@trident.arc.nasa.gov (Peter E. Yee)
Organization: NASA Ames Research Center, Moffett Field, CA
MAGELLAN WEEKLY STATUS
July 25, 1989
This is a weekly status report. The Magellan operations team is
continuing investigations into star scanner glitches and attitude
calibrations. The spacecraft is performing well, however.
The hottest Rocket Engine Modules were running at 69 degrees C
(156.2 F) to 74 C (165.2 F) with the temperature rising to 80 C (176
F) during momentum wheel desaturations. The current red alarm limit is
87 C (188.6 F), but tests are underway at Rocket Research to try to
push this limit higher. The head end of the Solid Rocket Motor (SRM)
is running at 34 degrees C (93.2 F) versus its current red alarm limit
of 70 C (158 F). Recent tests were performed at Motor Thiokol.
The spacecraft is continuing twice daily momentum wheel
desaturations and daily star calibrations. Additional star
calibrations were commanded as part of the gyro scale factor
calibrations, and two others were performed to test the star
scanner performance for a future star pair.
All the star calibrations involved in the spacecraft attitude
knowledge updates performed during the past week were successful
except for the one on July 20. That Starcal failed due to a glitch on
the second crossing of the first star, but the partial update from the
second star was sufficient. A preliminary report indicated solar
activity may have caused the problem.
Cruise load 7, the computer command sequence, was uplinked July
21 and a non-standard sequence was uplinked to Magellan on July 19
which specified a new star pair, Alpha Centauri and Gamma Crucis.
SPACECRAFT
Distance From Earth (mi) 11,979,386
Velocity Geocentric 11,477 mph
Heliocentric 69,445 mph
One Way Light Time 1 minute, 04 sec
|
| 456.43 | How Attitude Is Fixed | VOSTOK::LEPAGE | Truth travels slowly | Wed Jul 26 1989 17:45 | 59 |
| Re:.40
I don't know all the details of how Magellan's attitude control
systems works but I can give a more general explanation:
Three axis stabilized space probes such as Magellan typically use
two bright sources to maintain the proper attitude. In the earliest
space probes (e.g. Mariner 2 and the Rangers) the two sources choosen
were the Sun and the Earth. A sun sensor (which was position sensitive)
would keep the axis perpindicular to the solar panels pointing towards
the Sun (this also assured that there would be power). An Earth sensor
was mounted on the antenna assembly which was gimbaled. The gimbal was
set to the predicted position of the Earth and the spacecraft would
then roll around its sun axis until the bright Earth was aquired (thus
fixing the antenna towards Earth).
Later space probes used the star Canopus instead of the Earth for
the second attitude fix. In the case of Mariner 4, the high gain
antenna was fixed in such a position that it would point towards the
Earth when it reached Mars provided that it was oriented so that it
star sensor would look at Canopus (which is near the south ecliptic
pole). The process used to fix its attitude was similar to earlier
spacecraft; first the sun was aquired and then the spacecraft would
roll around its sun pointing axis until Canopus was found.
Unfortunately, Mariner 4 had many problems finding and keeping locked
on Canopus during its cruise to Mars. The star sensor would be
distracted by debris near the spacecraft, lose its lock and then it
would lock on the wrong star when it went searching for Canopus again.
Fortunately Mariner 4 was pointing in the right direction during its
flyby of Mars.
Subsequent space probes such as Mariner 9, Viking, Voyager, and
(most likely) Magellan use very similar methods. One axis is locked on
the Sun (or to one side of it in the case of Voyager) and the other was
locked typically on Canopus. Starting with Mariner 9, however, stars
other than Canopus were used. Later spacecraft were required to view
its target planet and lock its antenna on Earth through a larger range
of angles since the spacecraft was orbiting a planet or travelling for
so long that the Earth's apparent position would constantly change
during the data collection portion of the mission. Using stars other
than Canopus allowed the space probes to orient themselves over the
whole range of possible roll angles making observation and
communications much more flexible.
In addition to the Sun, Earth, and star sensors, space probes have
also made use of a gyroscopic inertial attitude system. This type of
system is used for brief periods of time when one or more of the
optical sensors lose its lock because of occultations by a planet or
other bodies and for special attitude changes for mid-course correction
or orbital insertion burns or for special observations. These inertial
sytems are, however, good for only short periods of time since they
have a tendency to drift. Therefore they require periodic updates from
the Sun and star sensors.
The type of system used on Magellan is probably very similar to
that used on earlier space probes. There is probably much more
flexibility built in since Magellan must be able to point its solar
panels at the Sun and point its antenna at Venus then turn to the
Earth. I still have not seen any details of its attitude control system
(although I haven't really looked for any information yet).
I hope that this has helped.
Drew
|
| 456.44 | MAGELLAN Status - August 7 | RENOIR::KLAES | N = R*fgfpneflfifaL | Thu Aug 10 1989 21:08 | 49 |
| Newsgroups: sci.space
Subject: Magellan Status for 08/07/89 (Forwarded)
Date: 10 Aug 89 18:31:41 GMT
Reply-To: yee@trident.arc.nasa.gov (Peter E. Yee)
Organization: NASA Ames Research Center, Moffett Field, CA
MAGELLAN WEEKLY STATUS
August 7, 1989
This is a weekly status report. The Magellan spacecraft continues
to perform twice daily momentum wheel desaturations and once daily
star calibrations for attitude update. Numerous additional Starcals
were performed to calibrate the star scanner to future guide stars and
safing stars.
Continuing solar activity during the past week has resulted in
spurious interrupts in the star tracker for four of the daily attitude
update Starcals and two of the star scanner calibrations. Seven
Starcals were fully successful.
On August 1, the operations team performed the first calibration
of the High-Gain Antenna (HGA), involving a series of spacecraft
maneuvers to sweep two axes of the HGA across the Deep Space Network
(DSN) station. The HGA maneuver went well with solid signals
throughout the sweep, but the Starcal performed before the HGA
calibration had a spurious interrupt and contaminated the initial
attitude accuracy. The data is being corrected to allow a computation
of HGA misalignment.
Results of testing at Rocket Research show no performance loss
for the half-pound thruster or the five-pound thruster at 110 degrees
C (230 F). The 100-pound engine did produce lower impulse-bits during
tests at 120 C (248 F) and 90 C (194 F), but it is unclear if this is
temporary or permanent. The answer will remain unresolved until the
final tests.
Computer sequence C-8 was uploaded August 4 and execution began
on August 7. Final sequence development for C-9 will commence
following approval of final sequence planning and preliminary sequence
development for C-10 has begun.
SPACECRAFT
Distance From Earth (miles) 16,173,246
Velocity Geocentric 16,458 mph
Heliocentric 72,992 mph
One Way Light Time 86.8 seconds
|
| 456.45 | Some stats on ULYSSES | RENOIR::KLAES | N = R*fgfpneflfifaL | Tue Sep 12 1989 13:15 | 27 |
| According to an European Space Agency (ESA) publication, the
ULYSSES solar probe mission ends after passing the Northern pole of
the Sun, 56 months after launch. The end of mission is 58 months
after launch.
ULYSSES will pass over the Southern pole of the Sun at a distance
of 30,000,000 km. Following the first passage it will cross the
ecliptic plane, headed for a pass of the Northern pole some eight
months later.
Since it has to go to Jupiter to get its acceleration to send the
spacecraft out of the ecliptic plane and to a polar orbit over the
Sun, it is equipped with RTGs.
There are no plans to put a "Murmurs of Earth" record on ULYSSES
[similar to the ones on VOYAGER 1 and 2 - see SPACE Topic 532].
Some ULYSSES mission plans:
Launch October 5, 1990
First superior conjunction August 1991
Jupiter encounter February 1992
First solar polar pass May-September 1994
Ecliptic crossing February 1995
Second solar polar pass May-September 1995
End of mission September 30, 1995
|
| 456.46 | What's an RTG? | EPIK::BUEHLER | Live today, for tommorrow isn't here yet | Mon Sep 18 1989 18:06 | 0 |
| 456.47 | RTG | VOSTOK::LEPAGE | Truth travels slowly | Mon Sep 18 1989 19:27 | 8 |
| Re:.46
Sorry: RTG stands for Radio-Thermal Generator. That's the short
hand name (i.e. acronym) for the nuclear power sources used on Pioneers
10 and 11, the Viking landers, and the Voaygers and will be used on
Galileo, Ulysses, Cassini, and CRAF.
Drew
|
| 456.48 | They don;t make them anymore... | JANUS::BARKER | Jeremy Barker - Reading, England | Thu Sep 21 1989 10:30 | 7 |
| Re: .47, .46
Actually Radioisotope Thermoelectric Generator. It uses the decay heat
of pieces of plutonium to generate a thermal EMF in a large array of
thermocouples.
jb
|
| 456.49 | MAGELLAN Status - September 19 | RENOIR::KLAES | N = R*fgfpneflfifaL | Thu Sep 21 1989 14:00 | 39 |
| Newsgroups: sci.space
Subject: Magellan Status for 09/19/89 (Forwarded)
Date: 21 Sep 89 00:25:40 GMT
Reply-To: yee@trident.arc.nasa.gov (Peter E. Yee)
Organization: NASA Ames Research Center, Moffett Field, CA
Magellan Weekly Status
Sept. 19, 1989
This is a weekly Magellan status report. Spurious interrupts were
experienced on four of the seven daily attitude update star calibrations
(Starcals) performed last week. Three of the four Star Scanner Unit
calibrations also experienced spurious interrupts. All reaction wheel
desaturations were nominal.
On Sept. 13, the spacecraft was maneuvered from Medium Gain
Antenna (MGA)-to-Earth to High Gain Antenna (HGA)-to-Earth attitude to
playback Starcal data so that analysts can investigate Star Scanner
Unit magnitude telemetry to gain additional insight into the spurious
interrupt problem.
The spacecraft continued to cool slightly after the MGA offpoint
maneuver at the beginning of the cruise 10 load. The solar panel
offpoint rotation test for 4.5 hours was accomplished on Sept. 15 to
reduce the energy passed through the shunting system. First
indications are that this did have some effect on several components.
The Attitude and Articulation Control Subsystem (AACS) memories
were partially read out on Sept. 14 and memory verification was
accomplished on Sept. 15.
Spacecraft
Distance from Earth (mi) 42,763,074
Velocity Geocentric 41,118 mph
Heliocentric 84,435 mph
One Way Light Time 3 mins, 54 sec
|
| 456.50 | Solar storms prove a hazard to MAGELLAN | RENOIR::KLAES | N = R*fgfpneflfifaL | Wed Oct 11 1989 14:08 | 28 |
| Newsgroups: sci.space
Subject: NASA Headline News for 10/10/89 (Forwarded)
Date: 10 Oct 89 21:10:02 GMT
Reply-To: yee@trident.arc.nasa.gov (Peter E. Yee)
Organization: NASA Ames Research Center, Moffett Field, CA
-----------------------------------------------------------------
Tuesday, Oct. 10, 1989 Audio: 202/755-1788
-----------------------------------------------------------------
This is NASA Headline News for Tuesday, October 10:
The MAGELLAN Venus spacecraft has weathered two major solar storms
on August 12 and September 29. The last occurrence of a storm of
comparable magnitude was in 1972. The two storms have resulted in
permanent, minor reductions of solar panel power output. They have
also caused large amounts of spurious star scanner outputs preventing
full attitude updates for several days following the storms. For
mapping, software filters are being installed which will lessen the
effects from the storms. MAGELLAN is now more than 57 million miles
from Earth.
-----------------------------------------------------------------
These reports are filed daily, Monday through Friday, at 12 noon,
Eastern time.
-----------------------------------------------------------------
A service of the Internal Communications Branch (LPC), NASA
Headquarters, Washington, D.C.
|
| 456.51 | MAGELLAN Update - October 17 | RENOIR::KLAES | N = R*fgfpneflfifaL | Thu Oct 19 1989 13:43 | 52 |
| Newsgroups: sci.space
Subject: Magellan Status for week of 10/17/89 (Forwarded)
Date: 19 Oct 89 03:39:48 GMT
Reply-To: yee@trident.arc.nasa.gov (Peter E. Yee)
Organization: NASA Ames Research Center, Moffett Field, CA
MAGELLAN WEEKLY STATUS
Oct. 17, 1989
This is the weekly Magellan status report. Monday, Oct. 16, the
Magellan spacecraft is 67,998,310 miles from Earth. Having passed
through perihelion on Oct. 7, the spacecraft is now slowing and is
traveling at 85,768 miles per hour relative to the Sun. The one-way
light time is 6 minutes and 5 seconds.
During perihelion, its closest approach to the Sun, Magellan
experienced some manageable performance degradation to the power
panels due to intense solar flare activity, the highest in decades.
Despite this unpredicted environment, the spacecraft has experienced
no permanent failures and remains healthy as it begins its climb away
from the Sun back to the vicinity of Earth orbit.
Six of the eight star calibrations performed during the reporting
period were fully successful. One had a spurious interrupt and the
other was missed due to accumulated errors following the change in
gyro channels.
On Oct. 6, the spacecraft was maneuvered to point the High- Gain
Antenna to Earth to playback star calibration data from Data
Management System (DMS) B. But accumulated gyro drift error caused the
antenna to point 1.8 degrees off target and the Deep Space Network
could not lock on to the telemetry. Plans are being made to replay the
data during the Cruise 14 load. The mission office also switched to
backup gyro channels. The drift was corrected and subsequent star
calibrations were successful.
The problem was thought to be vibration caused by increased
viscosity of motor shaft bearing lubricant resulting from lower
temperatures, and the problem is believed to be unique to one motor.
Remedies are being considered.
The Cruise 13 command load was uplinked Oct. 14. Cruise 14 will
be uplinked Nov. 3 and the stored sequence will begin on Nov. 6.
SPACECRAFT
Distance from Earth (mi) 67,998,310
Velocity Geocentric 59,421 mph
Heliocentric 85,768 mph
One-way light time 6 mins, 5 secs
|
| 456.52 | RTGs vs. Solar cells | REPAIR::RICKETTS | Have you tried kicking it? | Thu Oct 26 1989 06:00 | 7 |
| Re .48;
Why don't they use a similar arrangement, with a mirror to collect
heat from solar radiation, instead of solar panels? It would be
less vulnerable to damage by charged particles, radiation etc. Is
the power/weight ratio too poor, even with the removal of the plutonium
and its shielding etc.? Or is there some other reason?
|
| 456.53 | Not a Good Idea | MEMIT::SCOLARO | Fusion in a Glass! | Thu Oct 26 1989 12:33 | 34 |
| re .52
Well, I think your basic assumption is wrong. Solar radiation degrades
solar cells, it doesnt effect RTG's. Radiation, micro collisions and
just plain age degrade the expected output from solar cells. RTG's
lose power just about on the plutonium half life curve (very shallow).
It is also the power to weight ratio! and the collision cross section.
Remember gaileo is supposed to operate at jupiter, where the sunlight
is (I don't remember my celistial mechanics well enough, jupiter is
over 4X as far from the sun as the earth, is it 1/4th the sunlight or
1/16th?) as intesne as it is at the earth. If you wanted to use solar
cells, you would have to have batteries (for when the craft is in
shadow). You couldn't use mirrors, for a number of reasons, including
the need to point the mirrors to the sun to increase radiation and the
return antenna to the earth. This would greatly complicate the
spacecraft buss, because it must now accomidate s section pointing to
the sun, a spin stabalized section, a section for pointing the camera
to jupiter and a section for pointing the return antenna to earth (I
think the craft now has two sections performing antenna to earth and
spin stabilization on the same section, but this additional
requirement, for pointing a large solar array to the sun, might impose
constraints such that 4 sections would be required). Same would
probably occur for a just a large number of solar cells (no mirrors),
as you would have to either have a lot of solar cells, for
omnidirectional solar power, or point a somewhat smaller number to the
sun.
All of this leaves us with a rather large solar array. We know that
jupiter has rings and that io is constantly putting particles into
orbit, to say nothing of the io charged particle torus. All of these
could be deadly to solar cells.
Tony
|
| 456.54 | | MEMIT::SCOLARO | Fusion in a Glass! | Thu Oct 26 1989 12:43 | 16 |
| OOPS,
Brain on hold! I just thought the reply was referring to gaelio, as it
is presently the hottest topic. Most of the logic also referres to
ulysses, except that the solar cells would only have to be sized to
account for cruize power at jupiter.
However, the real problem with ulysses using solar cells will be the
degradiation of the solar electric output. Presently spacecraft
in earth lifetimes are limited by a number of things, one of which is
solar cell degradiation. Charged solar particles fry electronics.
some of the spacecraft's vital electronic control, radio and logic
circuts can be shielded and made redundant, solar cells, per force
cannot be shielded.
Tony
|
| 456.55 | Instead of solar cells, not instead of RTGs | REPAIR::RICKETTS | Have you tried kicking it? | Fri Oct 27 1989 06:18 | 25 |
| I think you misunderstood me. I know solar power is not much use
in the outer solar system; my question concerned using a thermocouple
array, as in the RTG but with the sun providing the heating element,
INSTEAD of solar cells. The arrangement would be something like;
sun hot terminal
mirror
o ----------------- I ) I cool terminal
This would generate an emf between the terminals; like solar cells,
it would have to be aligned towards the sun, batteries would be
needed, and it could only be used where the sun's radiation was
strong enough not to require an impracticably large array. Unlike
solar cells, its performance would not noticeably degrade over time
(unless it suffered collision damage). So why is such an arrangement
not used instead of solar cells? Too heavy/bulky, or some other
reason?
I'm sorry if I wasn't clear enough in my original note; maybe
I should have started a new topic, but I didn't want to for one
(I hoped) minor question. Moderator, feel free to move this if you
want to.
Ken
|
| 456.56 | Not Enough Light | VOSTOK::LEPAGE | Truth travels slowly | Fri Oct 27 1989 12:54 | 24 |
| Re:.55
Such an arrangement is possible but not practical due to its weight
and size. No matter what method is used to convert sunlight into
electricity (e.g. solar cells, thermocouples, etc.) there is only 5
milliwatts per square centimeter of power available at the distance of
Jupiter.
Off hand I don't know exactly what the power requirements for
Galileo are but they are on the order of a kilowatt. Assuming that
there exists a method to turn sunlight into electricity with 100%
efficiency (and there isn't), a collector about 4.5 meters on a side
would be required to collect all the needed power. If the "collector"
and the devices needed to convert light into electricity averaged 0.1
grams per square centimeter, the whole unit would weigh about 200 kg.
This is similar to the weight of the RTGs.
Unfortunately, in the real world, conversion efficiencies are
typically 10% and the weight of "collectors" would average closer to .2
to .5 gram per square centimeter. This would increase the weight of any
sort of solar based power supply into the 4,000 to 10,000 kg range. The
Galileo spacecraft only weighs about 2,500 kg to begin with! Any sort
of solar based power system is not practical at the distance of
Jupiter. There just isn't enough light available.
Drew
|
| 456.57 | Read the question, please. | REPAIR::RICKETTS | Have you tried kicking it? | Mon Oct 30 1989 06:04 | 11 |
| As I said, I KNOW they are not practical for use in the outer
solar system due to the low intensity of light, and the necessity
of using an inordinately large collecting area. The question was,
and I will try to make it as obvious as possible this time, Why
are thermocouple arrays not used in place of solar cells I.E. IN
SITUATIONS WHERE SOLAR CELLS WOULD NORMALLY BE USED? The majority of
spacecraft are still powered by solar cells, are they not? I already
KNOW why spacecraft headed for Jupiter and beyond use RTGs; I want
to know what performance advantages, if any, solar cells have over a
thermocouple array heated by the sun. They presumably have some,
or they wouldn't be used; but what are they?
|
| 456.58 | | MEMIT::SCOLARO | Fusion in a Glass! | Mon Oct 30 1989 12:06 | 20 |
| One clear advantage of solar cells over a thermocouple at the focus of
a mirror is pointing accuracy. Many of the craft in earth orbit with
solar cells have them on 360 degrees and spin in the sunlight. This
type of operational style would be inappropriate with a mirror and a
thermocouple. The solar cells are powered as the sine of the angle of
incidence of sunlight (i.e. 90 degrees = 1.0) for angles l.e. 180.
Mirrors lose almost all of their power when just slightly off angle.
There is also the issue of efficiency. Thermocouples are just a few
percent efficient. That is the heat energy is mostly not used to form
electricity. Solar cells are up to 20% efficient.
Then there is the issue of proven technology. Solar cells are quite
well proven and relatively inexpensive on a $40million spacecraft.
They work and there is no incentive to use something novel that may or
may not be any better, but could surely lose your whole investment if
it didn't work. (It is my limited understanding that spacecraft
designers are VERY conservitave when it comes to power systems.)
Tony
|
| 456.59 | MAGELLAN Status - October 31 | RENOIR::KLAES | N = R*fgfpneflfifaL | Thu Nov 02 1989 14:43 | 45 |
| Newsgroups: sci.space
Subject: Magellan Status for 10/31/89 [Corrected] (Forwarded)
Date: 2 Nov 89 01:15:34 GMT
Reply-To: yee@trident.arc.nasa.gov (Peter E. Yee)
Organization: NASA Ames Research Center, Moffett Field, CA
MAGELLAN WEEKLY STATUS
Oct. 31, 1989
CORRECTED: Pgh 4, It is the first software patch, not the first
star scanner, as indicated.
This is the weekly Magellan status report. Magellan on Tuesday,
Oct. 31, was 80,889,686 miles from Earth. Having passed through
perihelion on Oct. 7, the spacecraft is slowing as it begins its
return to the orbit of earth and is now traveling at a speed of 83,205
miles per hour relative to the sun.
With the exception of several failed star calibrations, Magellan
continues to operate nominally during the second third of its cruise.
None of the seven scheduled star calibrations performed last week
provided a complete autonomous attitude update. On Oct. 24, although
the star Beta Gruis was rejected due to the magnitude check, all four
star crossings were found to be valid. The attitude control system
analysts were then able to use the data to generate an attitude
knowledge correction. It was tested and uplinked on Oct. 27.
During the weekend, the command file to change star pairs was
tested and is expected to be uplinked Thursday, Nov. 2. Additionally,
the first software patch to help alleviate the star calibration
problem was uplinked to the spacecraft today, Oct. 31.
Preparations for Cruise load 14 and 15 are proceeding on
schedule. The start of Cruise 14 stored sequence is scheduled for Nov.
6 and Cruise 15 on Nov. 28.
SPACECRAFT
Distance from Earth (mi) 80,889,686
Velocity Geocentric 66,573 mph
Heliocentric 883,205 mph
One-way light time (Oct. 30) 7 mins, 10 secs
|
| 456.60 | MAGELLAN Status - November 15 | RENOIR::KLAES | N = R*fgfpneflfifaL | Thu Nov 16 1989 12:20 | 43 |
| Newsgroups: sci.space
Subject: Magellan Status for 11/15/89
Date: 15 Nov 89 21:35:27 GMT
Reply-To: yee@trident.arc.nasa.gov (Peter E. Yee)
Organization: NASA Ames Research Center, Moffett Field, CA
MAGELLAN STATUS REPORT
Nov. 15, 1989
Today, the Magellan spacecraft is 91,944,943 miles from Earth.
Having passed through perihelion on Oct. 7, the spacecraft is slowing
as it begins its return to the orbit of Earth and is now traveling at
a speed of 79,225 miles per hour relative to the Sun. Cruise
operations are proceeding as planned and Magellan remains healthy
except for star scanner and gyro problems.
Spurious star scanner signals at times prevent attitude control
knowledge updates. The signals are only a nuisance in cruise, but must
be fixed before Venus mapping. Software filters and operational
changes are being implemented in time for thorough testing prior to
the mapping phase. A software filter for the star scanner is to be
uplinked Thursday, Nov. 16.
Because of excessive attitude drift, an erratic gyro was switched
out of the attitude control circuitry. Four gyros are flown to provide
triple redundancy in the pitch and yaw axis and double redundancy in
the roll axis. Without the gyro, less redundancy will be available in
attitude control during Venus orbit insertion, considered a minor risk.
Intense solar activity experienced in August, September and
October has resulted in approximately a 6 percent solar panel
degradation to date. An active Sun was anticipated, however, in
sizing the solar panels and a margin of 35 percent was provided for.
SPACECRAFT
Distance from Earth (mi) 91,944,943
Velocity Geocentric 71,242 mph
Heliocentric 79,225 mph
One-way light time 8 mins, 14 secs
|
| 456.61 | Some technical troubles with MAGELLAN | RENOIR::KLAES | N = R*fgfpneflfifaL | Mon Dec 04 1989 14:52 | 53 |
| From: henry@utzoo.uucp (Henry Spencer)
Newsgroups: sci.space,sci.space.shuttle
Subject: Space news from October 9 AW&ST, part 2
Date: 4 Dec 89 00:13:27 GMT
Organization: U of Toronto Zoology
The Deep Space Network is gritting its teeth in preparation for
Magellan, which will tie up one DSN antenna almost continuously for
eight months with 3 terabits of radar data. Some loss of data is
likely if there is an emergency on another spacecraft or a need for
maintenance downtime on the DSN, although an extended mission could
fill in such gaps. [There is hope for an extended mission anyway,
since the eight-month primary mission will not do quite the entire
surface.]
Magellan is in good general health but does have some problems.
One is spurious signals in the star tracker, possibly caused by solar
protons or electrostatic discharges. The problems seem to be
correlated with solar activity. Pioneer Venus's similar tracker has
similar problems. The spurious signals are sufficiently away from
expected star positions that Magellan's attitude-control computer
rejects them, but they do mess up the attempt to determine Magellan's
attitude accurately. This is not a trivial problem, since Magellan
has to turn back and forth on each orbit to use the same antenna for
mapping and data transmission. Magellan will do a star calibration on
each orbit, and can miss *one* calibration without significant problems,
but successive missed calibrations could hamper communications and mess
up the radar data. JPL is developing software filters for the attitude-
control computer to reject well-out-of-bounds signals and pick the best
of the remaining ones; it is hoped that this will suffice.
Magellan's attitude-control computer is also running too warm,
which could shorten its life. The expected temperature was 40C, and
it's actually 58C. A small error has been found in the thermal
models, but it doesn't account for the whole problem. Nobody knows
quite what is going on; possibly the solar reflectors have become
degraded, but they have not done this on other missions. Mission
plans call for the high-gain antenna to shield the computer bay in
future, which should keep things under control.
Finally, Magellan's thrusters are too warm, especially when the
big ones have the Sun shining up their nozzles. Damage is not
expected, but one problem is that some of the hydrazine in the fuel
lines might decompose. The resulting gas bubbles might cause erratic
early firing, a matter of some concern because the big thrusters are
vital to proper attitude control when Magellan fires its solid motor
to enter Venus orbit. If studies of the problem suggest that
hydrazine decomposition is likely, the thrusters will be "burped" with
a short firing beforehand. Venus encounter date is Aug 10.
Mars can wait: we've barely | Henry Spencer at U of Toronto Zoology
started exploring the Moon. | uunet!attcan!utzoo!henry henry@zoo.toronto.edu
|
| 456.62 | MAGELLAN Update - December 5 | RENOIR::KLAES | N = R*fgfpneflfifaL | Tue Dec 05 1989 19:00 | 32 |
| Newsgroups: sci.space,sci.astro
Subject: Magellan Update 12/5/89 (Forwarded)
Date: 5 Dec 89 18:24:20 GMT
Reply-To: baalke@mars.jpl.nasa.gov (Ron Baalke)
Organization: Jet Propulsion Laboratory, Pasadena, CA.
Magellan Status Report
December 5, 1989
The Magellan probe has finished a third of its 795-million-mile
trip to Venus. Instead of an expected quiet ride, the trip has been
quite busy.
Instead of the expected 14 transmissions of operating commands to the
spacecraft, 150 command sequences have been beamed to Magellan so far.
Most have been related to either high temperatures or solar activity.
Solar flares have degraded solar panels and seem to be the reason
for voltage interruptions in the craft's star scanner. High temperatures
have plagued the propulsion and attitude control subsystems.
Engineers will begin testing to calibrate several instruments and
make sure the craft's radar is working. In January, the high-gain
antenna will be calibrated to make sure it is aligned. A small
mid-course trajectory maneuver is scheduled for mid-March to keep
Magellan on course for Venus.
Ron Baalke | baalke@mars.jpl.nasa.gov
Jet Propulsion Lab M/S 301-355 | baalke@jems.jpl.nasa.gov
4800 Oak Grove Dr. |
Pasadena, CA 91109 |
|
| 456.63 | MAGELLAN Update - December 12 | RENOIR::KLAES | N = R*fgfpneflfifaL | Wed Dec 13 1989 20:46 | 67 |
| Newsgroups: sci.space,sci.astro
Subject: Magellan Update 12/12/89
Date: 13 Dec 89 20:16:43 GMT
Reply-To: baalke@mars.jpl.nasa.gov (Ron Baalke)
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
December 12, 1989
Today, the Magellan spacecraft is 105,959,492 miles from Earth,
traveling at a speed of 71,336 miles per hour relative to the Sun.
Magellan is 221 days into the mission and the cruise is 48
percent completed with 241 days to Venus orbit insertion.
The telecom status now has the 12 foot High-Gain Antenna (HGA)
pointed to Earth with engineering data coming in at 1,200 bits per second.
The solar panels are providing 32.6 amps (1,030 watts) of power
and the panel degradation from solar particle events is at 11.5
percent, better than predicted for this point in the mission.
Intense solar activity experienced in August, September and
October caused the degradation, but an active sun was anticipated, and
a margin of 35 percent was provided for. Temperatures aboard Magellan
are normal as it continues to move out towards the orbit of Earth.
The successful daily star calibrations are maintaining the
spacecraft attitude to better than 0.04 degrees per day. Only one star
calibration has been missed since Nov. 16 when a new software filter
was inserted in the craft's attitude control computer.
To date the spacecraft has used only 5.7 kilograms of hydrazine
propellant with 123.8 kg remaining. This also is better than predicted.
Technical personnel and engineers are making good progress in
troubleshooting a "bit-slip/bit-flip" problem in data from Magellan's
tape recorder playbacks. A special Deep Space Network (DSN) telemetry
configuration was utilized during the scheduled playback on December
1. Playback data was processed in parallel through two strings, one
frame synchronized, and the other unsynchronized, in an attempt to
isolate the problem.
On November 30th, the first in-flight command to Magellan was
successfully transmitted via the Deep Space Network's X-band uplink.
This activity was conducted at Canberra, Australia, and represents a
significent increase in the project and DSN command capability.
Thermally, Magellan is stable and temperatures aboard the
spacecraft are normal as it continues to move out towards the orbit of
Earth. Magellan is now 179 million miles from Venus which it will
orbit next August and begin mapping in September with its imaging
radar instruments.
SPACECRAFT
Distance from Earth (mi) 105,959,492
Velocity Heliocentric 71,336 mph
One-way light time 9 mins, 29 secs
Ron Baalke | baalke@mars.jpl.nasa.gov
Jet Propulsion Lab M/S 301-355 | baalke@jems.jpl.nasa.gov
4800 Oak Grove Dr. |
Pasadena, CA 91109 |
|
| 456.64 | MAGELLAN Update - January 3 | RENOIR::KLAES | N = R*fgfpneflfifaL | Thu Jan 04 1990 12:15 | 69 |
| Newsgroups: sci.space,sci.astro
Subject: Magellan Update 1/3/90
Date: 4 Jan 90 00:34:59 GMT
Reply-To: baalke@mars.jpl.nasa.gov (Ron Baalke)
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
Jan. 3, 1990
Today, the Magellan spacecraft is 111,898,063 miles from Earth,
traveling at a speed of 65,982 miles per hour relative to the sun. One
way light time is 10 minutes and one second.
On Dec. 31, the spacecraft's computers detected an error in the
privileged memory and took several actions to protect itself.
First, the command data system (CDS) switched to its backup unit,
side B, which took control to make sure the solar panels were properly
aligned and the medium gain antenna pointed to Earth. The on-board
cruise sequence, which was composed solely of momentum wheel
desaturations and star calibrations, was cancelled by the CDS when the
change over was made.
The telemetry link was switched from the high gain to the medium
gain antenna and the rate was reduced from 1,200 bits per second (bps)
to 40 bps.
Also, the command link was switched from the high gain to the low
gain and the rate was reduced from 62.5 bps to 7.8 bps.
A momentum wheel desaturation is being done once daily via
non-standard commands to the spacecraft, and because of the low
attitude drift rates no star calibrations have been needed.
Magellan operations officials said the difficulty appears to be a
memory cell oxide problem, but there is a possibility an energetic
particle from recent high solar activity could have caused a memory
hit in one of the science instruments.
Magellan spokesman Dr. Ed Sherry said operations teams at JPL and
at Martin Marietta in Denver will troubleshoot the problem over the next
8 to 10 days and then uplink a new sequence to resume normal cruise.
The "bit-slip/bit-flip" problem was further isolated on radar
tests performed on Dec. 12 through Dec. 14. The problem was occuring
on only track 2 on one of the two tape recorders aboard Magellan. Deep
Space Network was eliminated as a possible cause as data was run
through two different DSN pathways, with the problem seen on both
paths. This ruled out the Frame Synchronization Subassembly (FSS) and
the Maximum Likelihood Convolutional Decoder (MCD) which were
originally have been thought as a possible cause of the problem.
There is no impact to the mapping phase of the mission due to
this problem since only 2 tracks are needed from each tape recorder to
record data. Each tape recorder has 4 tracks.
SPACECRAFT
Distance from Earth (mi) 111,898,063
Velocity Heliocentric 65,982 mph
One-way light time 10 mins, 1 sec
Ron Baalke | baalke@mars.jpl.nasa.gov
Jet Propulsion Lab M/S 301-355 | baalke@jems.jpl.nasa.gov
4800 Oak Grove Dr. |
Pasadena, CA 91109 |
|
| 456.65 | Trouble with MAGELLAN | RENOIR::KLAES | N = R*fgfpneflfifaL | Fri Jan 05 1990 12:48 | 53 |
| From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Special Report - 01/04/90
Date: 4 Jan 90 19:17:57 GMT
Reply-To: baalke@mars.jpl.nasa.gov (Ron Baalke)
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN SPECIAL REPORT
Jan. 4, 1990
Magellan's command and data system (CDS) experts said today an
error the spacecraft detected in its privileged memory is apparently
an oxide problem, and not a single event upset caused by solar
radiation. There is no evidence that the spacecraft is currently
encountering high solar activity.
Operations people said they switched back to the CDS primary, or
side-A computer, to verify and localize the error with memory
readouts. If the problem proves to be an error, called a parity error,
operations will either program around the weak cell or switch back to
the redundant memory.
Standard cruise operations will be reinstated on CDS side-A with
the cruise-17 standard sequence scheduled to start on January 15.
In the meantime, spacecraft safing operations include:
--daily momentum wheel desaturations
--attitude control parameter updates for the read-only-
memory safing mode every other day
--star calibrations on each Friday.
A mini-computer sequence will be generated to accomplish the
safing operations to minimize the non-standard commanding of the
spacecraft. All commands are tested in the verification laboratory
before being sent to the spacecraft.
Yesterday, the station in Australia was unable to acquire the
spacecraft with any command uplinks for 51 minutes. Large doppler
residuals were observed in the tracking data just prior to the outage.
The station in Madrid, Spain, continues to attempt the uplink with
various sweep combinations.
Operations has switched the command link from the low gain to the
medium gain antenna.
Ron Baalke | baalke@mars.jpl.nasa.gov
Jet Propulsion Lab M/S 301-355 | baalke@jems.jpl.nasa.gov
4800 Oak Grove Dr. |
Pasadena, CA 91109 |
|
| 456.66 | MAGELLAN Update - January 17 | WRKSYS::KLAES | N = R*fgfpneflfifaL | Fri Jan 19 1990 13:08 | 39 |
| Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 01/17/90
Date: 18 Jan 90 18:51:59 GMT
Reply-To: baalke@mars.jpl.nasa.gov (Ron Baalke)
MAGELLAN STATUS REPORT
Jan. 17, 1990
Today, the Magellan spacecraft is 113,471,037 miles from Earth,
traveling at a speed of 63,409 miles per hour relative to the sun. One
way light time is 10 minutes and 12 seconds.
The spacecraft has been successfully switched back to its primary
command data system computer, and to the high-gain antenna. The data
rate is again at 1,200 bits per second. Earlier this month the
spacecraft detected an error in its memory and went into a safing
mode. It switched to its backup CDS computer and the telemetry link
was switched from the high gain to the medium gain antenna and the
rate was reduced from 1,200 bits per second to 40 bps.
Also, the command link was switched from the high gain to the low
gain and the rate was reduced from 62.5 bps to 7.8 bps.
On January 12, the spacecraft went into fault protection mode due
to a wrong command to the spacecraft from the spacecraft team. After
performing a sweep at 300Hz with a tuning rate of 5Hz/sec, two way
communications was once again established.
A momentum wheel desaturation was done once daily via non-
standard commands to the spacecraft.
Magellan operations team members said Magellan is back on
schedule for the start of Cruise-17 command sequence
Ron Baalke | baalke@mars.jpl.nasa.gov
Jet Propulsion Lab M/S 301-355 | baalke@jems.jpl.nasa.gov
4800 Oak Grove Dr. |
Pasadena, CA 91109 |
|
| 456.67 | MAGELLAN Update - January 25 | WRKSYS::KLAES | N = R*fgfpneflfifaL | Fri Jan 26 1990 13:29 | 43 |
| Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 01/25/90
Date: 26 Jan 90 00:01:06 GMT
Reply-To: baalke@mars.jpl.nasa.gov (Ron Baalke)
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
Jan. 25, 1990
Today, the Magellan spacecraft is 113,712,818 miles from Earth,
traveling at a speed of 62,258 miles per hour relative to the sun. One
way light time is 10 minutes and 11 seconds.
The spacecraft resumed operations in the standard cruise mode
again on Jan. 18, as planned, with the beginning of cruise computer
sequence 17.
The spacecraft had invoked its fault protection software on Dec.
31 when it detected a memory error in the high-level privileged memory.
The fault protection put the spacecraft into a safety mode and shut off
the prime-A command and data subsystem and went to its backup system.
The spacecraft also automatically switched from the high-gain
antenna to the medium-gain antenna and reduced the downlink telemetry
from 1,200 bits per second to 40 bps. Successful reaction wheel
desaturations and star calibrations were performed by ground commands.
The spacecraft's health and routine operations were confirmed
today by Magellan operations.
SPACECRAFT
Distance from Earth (mi) 113,712,818
Velocity Heliocentric 62,258 mph
One-way light time 10 mins, 11 sec
Ron Baalke | baalke@mars.jpl.nasa.gov
Jet Propulsion Lab M/S 301-355 | baalke@jems.jpl.nasa.gov
4800 Oak Grove Dr. |
Pasadena, CA 91109 |
|
| 456.68 | MAGELLAN Update - February 14 | WRKSYS::KLAES | N = R*fgfpneflfifaL | Thu Feb 15 1990 17:13 | 45 |
| Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 02/14/90
Date: 15 Feb 90 17:13:23 GMT
Reply-To: baalke@mars.jpl.nasa.gov (Ron Baalke)
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
Feb. 14, 1990
Magellan is 112,633,595 miles from Earth, traveling at a speed of
60,419 miles per hour relative to the Sun. One way light time is 10
minutes and 10 seconds. During the next 12 weeks the spacecraft
distance from Earth diminishes as Magellan passes through aphelion.
It then will begin to arc back toward the orbit of Venus for its
August 10 encounter.
The Magellan spacecraft is in normal cruise today and has
successfully completed a high-gain antenna calibration. Very little
spacecraft activity is planned during the next few months with the
spacecraft close to Earth orbit in a low power state.
The Deep Space Network Operations team has completed Phase 1 of
the Magellan Orbital Ops Mission Readiness Test (MRT) program, which
exercised the 70-meter stations in realistic mapping support scenarios.
A new Goldstone Venus radar image has been processed. It covers
an area approximately 1,000 km (620 mi) across near the Prime Meridian
along the equator and includes a feature called Heng-o Chasma. In the
image the feature appears to be a type of ovoid structure 1,200 km
(744 miles) in diameter, called a corona. If it is this type of
structure, it would be the largest one so far identified on Venus.
SPACECRAFT
Distance from Earth (mi) 112,633,595
Velocity Heliocentric 60,419 mph
One-way light time 10 mins, 10 sec
Ron Baalke | baalke@mars.jpl.nasa.gov
Jet Propulsion Lab M/S 301-355 | baalke@jems.jpl.nasa.gov
4800 Oak Grove Dr. |
Pasadena, CA 91109 |
|
| 456.69 | MAGELLAN Update - February 21 | WRKSYS::KLAES | N = R*fgfpneflfifaL | Thu Feb 22 1990 14:54 | 51 |
| Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 02/21/90
Date: 22 Feb 90 05:31:56 GMT
Reply-To: baalke@mars.jpl.nasa.gov (Ron Baalke)
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
February 21, 1990
The Magellan spacecraft is 112,068,231 miles from Earth, traveling
at a speed of 60,193 miles per hour relative to the sun. One way light
time is 10 minutes and 3 seconds. Magellan is also 77,855,922 miles
from Venus.
Magellan continues in normal cruise, successfully achieving most
star scans. However, an Attitude Reference Unit (ARU) calibration
attempted on February 9 may need to be repeated because of the loss
of some of the star calibration data due to star scanner spurious
signals. This is under investigation.
There were no uplinks to the spacecraft and the only spacecraft
activities besides the twice daily DESATs and daily STARCAL were a
two-hour "no uplink" signal test by the Deep Space Network station,
and an onboard update of the Emergency Over-Temperature Attitude. The
first five STARCALS for the week were successful on both stars, with
daily attitude updates averaging 0.05 degrees. The final two STARCALS
each missed Alpha Lyra (Vega).
The ARU calibration is three consecutive STARCAL's performed with
three mutually orthogonal stars. The preliminary real-time indication
was that 4 of the 12 star expected crossings failed. Three of the four
were due to one star's magnitude check and the other one was due to a
spurious interrupt. The present plan is to repeat the ARU calibration
in Cruise Sequence 21 or early 22 using the information learned from
the first ARU calibration attempt. Several STARCALs before and after
the ARU attempt has been successful which leads us to be optimistic
as to the outcome of the second try.
SPACECRAFT
Distance from Earth (mi) 112,068,231
Velocity Heliocentric 60,193 mph
One-way light time 10 mins, 3 sec
Ron Baalke | baalke@mars.jpl.nasa.gov
Jet Propulsion Lab M/S 301-355 | baalke@jems.jpl.nasa.gov
4800 Oak Grove Dr. |
Pasadena, CA 91109 |
|
| 456.70 | MAGELLAN Update - March 2 | WRKSYS::KLAES | N = R*fgfpneflfifaL | Sun Mar 04 1990 17:05 | 42 |
| Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 03/02/90
Date: 2 Mar 90 21:29:10 GMT
Reply-To: baalke@mars.jpl.nasa.gov (Ron Baalke)
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
March 2, 1990
The Magellan spacecraft is 111,126,334 miles from Earth,
traveling at a speed of 60,034 miles per hour relative to the Sun.
One way light time is 9 minutes and 58 seconds. Magellan is also
72,023,216 miles from Venus.
The spacecraft continues in normal, quiet cruise and has
successfully achieved all STARCALs since February 10. Magellan reached
aphelion on March 1 and began its final arc inward toward the Sun and
Venus Orbit Insertion (VOI) currently on Cruise 19.
A successful attitude reference hold using the thrusters was
accomplished on February 23. This is an important pre-VOI test since
VOI uses the same sequence of attitudes.
Flight software will be changed to add a background filter to the
star scan process which will allow for all crossing data in an
interrupt window to be buffered. The filter will then select the two
best crossings, based on magnitude of each star. This change will
reduce the number of failed star scans.
SPACECRAFT
Distance from Earth (mi) 111,126,334
Velocity Heliocentric 60,034 mph
One-way light time 9 min 58 sec
Ron Baalke | baalke@mars.jpl.nasa.gov
Jet Propulsion Lab M/S 301-355 | baalke@jems.jpl.nasa.gov
4800 Oak Grove Dr. |
Pasadena, CA 91109 |
|
| 456.71 | MAGELLAN Update - March 12 | WRKSYS::KLAES | N = R*fgfpneflfifaL | Mon Mar 12 1990 17:22 | 34 |
| Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 03/12/90
Date: 12 Mar 90 17:33:59 GMT
Reply-To: baalke@mars.jpl.nasa.gov (Ron Baalke)
Organization: Jet Propulsion Laboratory, Pasadena, CA.
Magellan
Mission Status Report
March 12, 1990
The Magellan spacecraft continues to operate nominally as it
passed through aphelion on March 1. The spacecraft is now
approximately 111 million miles from Earth and traveling at a speed of
just over 60,000 miles/hour relative to the Sun. The distance to
Earth will continue to decrease over the next two months to a minimum
of 103 million miles before increasing again on the final leg of the
long cruise to Venus.
All seven STARCALS were successful, with an average attitude
update of 0.04 degrees. Other spacecraft activities included
supporting a Very Large Baseline Interferometry (VLBI) test and three
different Telecommunication Subsystem tests: the third Deep Space
Network Mission Readiness Test, a Static Phase Error Test and an
Automatic Gain Control Calibration.
No battery reconditioning will be done before Venus Orbit Insertion
(VOI). There is a possibility that small (5%) losses might occur during
the first and second periapsis occultations in the prime mission.
Ron Baalke | baalke@mars.jpl.nasa.gov
Jet Propulsion Lab M/S 301-355 | baalke@jems.jpl.nasa.gov
4800 Oak Grove Dr. |
Pasadena, CA 91109 |
|
| 456.72 | MAGELLAN Update - March 21 | WRKSYS::KLAES | N = R*fgfpneflfifaL | Thu Mar 22 1990 11:26 | 41 |
| Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 03/21/90
Date: 21 Mar 90 23:33:44 GMT
Reply-To: baalke@mars.jpl.nasa.gov (Ron Baalke)
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN
Mission Status Report
March 21, 1990
The Magellan spacecraft is now 107,890,103 miles from Earth,
54,483,662 miles from Venus, and travelling at a heliocentric speed of
60,594 miles/hour. Magellan continues to run in a normal, quiet cruise
as it approaches Venus.
All STARCALS were successful except for the one on March 9.
Gyroscopes B1 and B2 were turned on prior to the Trajectory Course
Maneuver (TCM-2) and exhibited erratic current loads which then
resulted in their being turned off. It is expected that this condition
may improve as the gyros warm up when the spacecraft approaches Venus
Orbit Insertion (VOI). The two attitude updates following the turn-on
of Gyros B1/B2 averaged 0.125 degrees, about 3 or 4 times the average
prior to and following the turn-on.
TCM-2 took place at 10 AM (PST) on March 13 and was judged to
have been successfully accomplished base on spacecraft telemetry data.
All spacecraft telemetry was as expected. Engine burn time was correct
and there was no indication of leakage after shutdown.
The maneuver was programmed to achieve a 0.509 meter/second
change in velocity. The Navigation team has confirmed after analysis
of doppler shift data that Magellan achieved a 0.466 meter/second
velocity change. This is within one sigma of nominal and is more than
adequate for this manuever. Additional manuevers are not required
outside of the planned TCM-3 manuever scheduled for July.
Ron Baalke | baalke@mars.jpl.nasa.gov
Jet Propulsion Lab M/S 301-355 | baalke@jems.jpl.nasa.gov
4800 Oak Grove Dr. |
Pasadena, CA 91109 |
|
| 456.73 | MAGELLAN Update - April 3 | WRKSYS::KLAES | N = R*fgfpneflfifaL | Wed Apr 04 1990 20:34 | 34 |
| Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 04/03/90
Date: 4 Apr 90 00:49:54 GMT
Reply-To: baalke@mars.jpl.nasa.gov (Ron Baalke)
Organization: Jet Propulsion Laboratory, Pasadena, CA.
Magellan
Mission Status Report
April 3, 1990
The Magellan spacecraft is now 105,455,042 miles from Earth,
41,408,204 miles from Venus, and traveling at a heliocentric speed of
61,997 miles/hour. One way light time is 9 minutes 27 seconds.
Magellan continues in normal, quiet cruise mode. All Starcals were
successful and the attitude updates averaged 0.058 degrees.
Two significant uploads were successfully accomplished. The
first was a change to the filler bit pattern which the Command and
Data Subsystem (CDS) puts in the telemetry stream just prior to the
high rate playback frame synch word, to assist in solving the
"slip-a-bit, flip-a-bit" problem on the Data Management Subsystem
(DMS) playback. The other was the background filter in the Attitude
and Articulation Control Subsystem (AACS-A) to correct the type A
spurious interrupts from the Star Tracker Unit believed caused by high
energy photons. The B-side filter was uploaded on March 26. On April
2, new AACS parameters were updated for earth-point, cruise and Sun
polynomials for the Cruise 21 sequence. Cruise 21 will last through
April 23.
Ron Baalke | baalke@mars.jpl.nasa.gov
Jet Propulsion Lab M/S 301-355 | baalke@jems.jpl.nasa.gov
4800 Oak Grove Dr. |
Pasadena, CA 91109 |
|
| 456.74 | MAGELLAN Update - April 17 | 26523::KLAES | The Universe, or nothing! | Mon Apr 23 1990 19:17 | 38 |
| Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 04/17/90
Date: 23 Apr 90 16:35:55 GMT
Reply-To: baalke@mars.jpl.nasa.gov (Ron Baalke)
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
April 17, 1990
The Magellan spacecraft is 104 million miles from Earth and 34
million miles from Venus today and continues its cruise with all
subsystems performing nominally.
The spacecraft is traveling at 63,320 mph relative to the sun and
closing on Venus at 35,415 mph relative to that planet.
Last week ended with a successful Attitude Reference Unit
Calibration (ARUCAL), the first of the mission after two previous
aborted attempts. The tape recorded ARUCAL data will be analyzed later
this week.
All star calibrations during the week were successful with an
average attitude update of 0.04 degrees. Two Deep Space Network
readiness tests were successfully supported.
SPACECRAFT
Distance from Earth (mi) 103,621,828
Velocity Heliocentric 64,233 mph
One-way light time 9 mins, 16 secs
Ron Baalke | baalke@mars.jpl.nasa.gov
Jet Propulsion Lab M/S 301-355 | baalke@jems.jpl.nasa.gov
4800 Oak Grove Dr. |
Pasadena, CA 91109 |
|
| 456.75 | MAGELLAN Update - April 24 | 26523::KLAES | The Universe, or nothing! | Wed Apr 25 1990 15:21 | 37 |
| Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 04/24/90
Date: 24 Apr 90 22:28:29 GMT
Reply-To: baalke@mars.jpl.nasa.gov (Ron Baalke)
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
April 24, 1990
The Magellan spacecraft is 103 million miles from Earth and 24.5
million miles from Venus today and continues its cruise with all
subsystems performing well.
The spacecraft is traveling at 65,555 mph relative to the Sun.
The speed will continue to increase as Magellan is pulled by the Sun's
gravity toward its rendezvous with Venus, and will be more than 86,000
mph in late July.
All star calibrations during the past week were successful with
an average attitude update of 0.04 degrees. Magellan began its Cruise
22 sequence Monday. The sequence was loaded on April 12. The flight
team conducted a mapping exercise from April 9 through April 12, and a
repeat is scheduled in early June.
SPACECRAFT
Distance from Earth 103,126,075 miles
Velocity Heliocentric 65,555 mph
One-way light time 9 mins, 14 secs
Ron Baalke | baalke@mars.jpl.nasa.gov
Jet Propulsion Lab M/S 301-355 | baalke@jems.jpl.nasa.gov
4800 Oak Grove Dr. |
Pasadena, CA 91109 |
|
| 456.76 | MAGELLAN Update - April 30 | 26523::KLAES | The Universe, or nothing! | Tue May 01 1990 17:55 | 42 |
| Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 04/30/90
Date: 1 May 90 00:12:54 GMT
Reply-To: baalke@mars.jpl.nasa.gov (Ron Baalke)
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
April 30, 1990
The Magellan spacecraft is now 103 million miles from Earth and
nearly 21 million miles from Venus as of Monday, April 30. The cruise
continues with all subsystems performing well. The spacecraft is
traveling at 66,824 mph relative to the Sun.
Cruise sequence 22 was uploaded and is being executed perfectly.
It changed to a new star pair for star calibrations. They are now Beta
Gruis and Alpha Aquilae.
Five of the seven daily star calibrations were fully successful
with an average attitude update of 0.05 degrees. Two of them, on
Tuesday and Thursday, were partially successful, with only single star
updates, due to the rejection of Beta Gruis on both occasions by the
star scanner unit's foreground filter. The spacecraft team is
analyzing the playback data for those events.
Last week also saw the completion of memory readouts of all
command data system redundant memories in both the A and B sides. No
parity errors were found.
SPACECRAFT
Distance from Earth (mi) 102,942,136
Velocity Heliocentric 66,824 mph
One-way light time 9 mins, 12.5 secs
Ron Baalke | baalke@mars.jpl.nasa.gov
Jet Propulsion Lab M/S 301-355 | baalke@jems.jpl.nasa.gov
4800 Oak Grove Dr. |
Pasadena, CA 91109 | Go Lakers!
|
| 456.77 | MAGELLAN Update - May 7 | 26523::KLAES | The Universe, or nothing! | Tue May 08 1990 14:51 | 43 |
| Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 05/07/90
Date: 7 May 90 23:24:51 GMT
Reply-To: baalke@mars.jpl.nasa.gov (Ron Baalke)
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
May 7, 1990
The Magellan spacecraft continues in cruise today with all
systems performing well. The spacecraft is 103,064,245 miles from
Earth and 17 million miles from Venus today. Heliocentric velocity is
68,454 miles per hour. One way light time is 9 minutes and 12 seconds.
The flight team last Friday celebrated the first anniversary of
the May 4, 1989 launch from space shuttle Atlantis, and marked 100
days before Magellan goes into orbit around Venus.
Last week began with an uncertain performance by the star tracker
on a new set of stars in the Cruise 22 sequence. But an upload of new
magnitude and threshold parameters solved the problem.
Five of the seven daily star calibrations were fully successful;
the last four in a row were perfect with an average attitude update of
less than 0.05 degrees.
A three-day readiness review at JPL for Venus Orbit Insertion
(VOI) and In-Orbit Correction (IOC) and the May Cruise Mapping Test
was satisfactorily completed.
SPACECRAFT
Distance from Earth (mi) 103,064,245
Velocity Heliocentric 68,454 mph
One-way light time 9 mins, 12 secs
Ron Baalke | baalke@mars.jpl.nasa.gov
Jet Propulsion Lab M/S 301-355 | baalke@jems.jpl.nasa.gov
4800 Oak Grove Dr. |
Pasadena, CA 91109 | Go Lakers!
|
| 456.78 | MAGELLAN Update - May 21 | 26523::KLAES | The Universe, or nothing! | Mon May 21 1990 19:57 | 46 |
| Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 05/21/90
Date: 21 May 90 17:29:39 GMT
Reply-To: baalke@mars.jpl.nasa.gov (Ron Baalke)
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
May 21, 1990
The Magellan spacecraft continues in excellent health today. The
spacecraft is 104 million miles from Earth and 13 million miles from
Venus. Heliocentric velocity is 71,000 miles per hour. One way light
time is 9 minutes and 19 seconds.
The first week of a two-week Cruise Mapping Test was completed on
May 17. On May 14, the radar start-up test successfully cycled the
radar instrument on and off through each operating mode. The test
also verified that the telemetry was normal and the problem with
receiving data seen in the test last December has been corrected.
On May 16, the radar functional test was successfully performed,
putting the spacecraft in a 8 minute "mapping pass" complete with a
requisite star calibration and tape recorder playbacks. No anomalies
were experienced on the spacecraft although a couple of minor
anomalies were discovered, and corrected, in the ground data
processing software and procedures.
The daily star calibrations during the week were all successful
with average attitude updates of less than 0.05 degrees. Several
non-standard commands were successfully transmitted, including a
resetting of battery and radar thermal control limits, resetting tape
recorder tape position counters, and the commands to initiate the
various test activities.
SPACECRAFT
Distance from Earth (mi) 104,101,936
Velocity Heliocentric 71,313 mph
One-way light time 9 mins, 19 secs
_ _____ _
| | | __ \ | | Ron Baalke | baalke@mars.jpl.nasa.gov
| | | |__) | | | Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
___| | | ___/ | |___ M/S 301-355 |
|_____| |_| |_____| Pasadena, CA 91109 |
|
| 456.79 | MAGELLAN Update - May 22 | 26523::KLAES | The Universe, or nothing! | Tue May 22 1990 17:15 | 51 |
| Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 05/22/90
Date: 22 May 90 15:13:08 GMT
Reply-To: baalke@mars.jpl.nasa.gov (Ron Baalke)
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN
MISSION STATUS REPORT
May 22, 1990
The Magellan project is in the midst of conducting a Cruise Radar
Mapping Test. The test consists of 3 parts: Radar Turn-on Test, Radar
Functional Test, and Radar "Mapping" Test.
The Radar Turn-on Test was conducted on Monday, May 14, when each
component of the Radar was first switched ON and OFF sequentially
followed by the entire Radar System being powered ON and then OFF.
The radar was inhibited from radiating during this test. Analysis of
the data has shown that the test was totally successful and the Radar
Team gave the "Go" for the Functional Test.
The Radar Functional Test was conducted on Wednesday, May 16. In
this test the Radar was powered ON in cruise configuration and
commanded to radiate for eight minutes. The spacecraft then played
the data back at 115.2 Kbits/second (so that the 34 meter antenna
station in Goldstone, California (DSS 12) and the 34 meter antenna
station in Australia (DSS-42) could ship the data to JPL in real-time
for analysis). Both Deep Space Network (DSN) stations acquired both
playbacks in less than 1 minute. Additionally a star calibration
(STARCAL) was performed between the two parts of the playback yielding
an update of 0.008 degrees. Again, analysis of the data has shown
that the test was totally successful.
The Radar "Mapping" Test will be conducted on from May 21 through
May 25, with the Magellan spacecraft performing some 27 simulated
orbits. The spacecraft will function as if it is in orbit turning to
mapping attitude; the radar radiating ("mapping"); turning to Earth
for playback; playing back the data; performing Star Calibrations and
momentum wheel desaturations; playing back the remaining data and
readying itself for the next orbit. All teams will be in place and
the data will flow through the DSN, Space Flight Operations Center
(SFOC), the Magellan High Rate system, the image processing lab and
finally to the Data Management and Archive Team (DMAT). This test is
planned to provide all the Project's teams with a real-time training
exercise as part of an End-to-End test.
_ _____ _
| | | __ \ | | Ron Baalke | baalke@mars.jpl.nasa.gov
| | | |__) | | | Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
___| | | ___/ | |___ M/S 301-355 |
|_____| |_| |_____| Pasadena, CA 91109 |
|
| 456.80 | MAGELLAN Update - May 24 | 26523::KLAES | The Universe, or nothing! | Thu May 24 1990 18:52 | 77 |
| Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 05/24/90
Date: 24 May 90 16:24:27 GMT
Reply-To: baalke@mars.jpl.nasa.gov (Ron Baalke)
Organization: Jet Propulsion Laboratory, Pasadena, CA.
Magellan Status Update
Cruise Mapping Test
May 24, 1990
The Magellan spacecraft is going through a Radar Mapping Test
this week with the spacecraft performing 27 simulated orbits. This
test is an End-to-End test which provides all of the project's teams a
real-time training exercise. The radar data will flow from the
spacecraft through the Deep Space Network (DSN), Space Flight
Operations Center (SFOC), the Magellan High Rate system, the image
processing lab, and the Data Management and Archive Team (DMAT).
Part 1 Orbits #2 through #6
This section covers the first five orbits of the Cruise Mapping
Test which began at 4:58:58 PM PDT on Monday, 21 May 1990. Orbit #6
ended at 9:38:58 AM on Tuesday, 22 May 1990. (Note: The Cruise
Mapping Test began with Orbit #2 as Orbit #1 was assigned to the Radar
Functional Test a week ago.)
The spacecraft has performed nominally during all simulated
orbits. Each star calibration during the first 5 mapping orbits was
successful beginning with 0.05 degree updates in the early orbits and
settling down to 0.02 degrees. Momentum wheel desaturations were
performed on Orbit #3 and Orbit #6.
The Radar System Team reports that the Radar is performing
nominally and no alarms have been seen. All temperatures of the radar
system have remained within predicted limits.
The first orbit's data (Orbit #2) was relayed from the 70 meter
antenna in Canberra, Australia (DSS-43) to JPL at 115.2 KBPS. Orbit
#3 data from the 34 meter antenna in Madrid, Spain (DSS 61) was also
relayed to JPL at 115.2 KBPS. The first expedited product has been
converted by the Magellan High Rate (MHR) system to an Experiment Data
Record (EDR). Data taken from the Canberra and Madrid passes will be
flown to JPL. Data tapes from the Goldstone passes are to be trucked
to JPL each evening for processing to begin at midnight tonight.
Out of 7 Deep Space Network (DSN) acquisitions, 5 met the 1
minute acquisition performance criteria. One problem was encountered
on Orbit 2, Segment 1 at DSS-43 where a Digital Data Recorder (DDR)
failed, resulting in a total loss of 6 minutes of data.
Part 2 Orbits #7 through #12
This section covers Orbits #7 of the Cruise Mapping Test which
began at 9:38:58 AM PDT on Tuesday, 22 May 1990 through Orbit #12
which ended at 5:38:58 AM on Wednesday, 23 May 1990.
The spacecraft continues to perform nominally during all
simulated orbits. Each star calibration of the 6 orbits were
successful with an average per orbit update of 0.014 degrees.
Momentum wheel desaturations were performed on Orbit #9 and Orbit #12.
The solar panel's sun loss sensor went into red alarm on each orbit
today as it did yesterday. The cause of this is the requirement for
the panels to unwind as the S/C turns to simulate the mapping orbits.
This was an expected occurrence and the count number was as predicted
as the panels have to unwind approximately 350 degrees. The alarm has
been turned off for the remainder of the Cruise Mapping Test (CMT).
The Radar Team reports that the Radar system is performing
nominally and no alarms have been seen. Out of 15 acquisitions, 13
met the 1 minute criteria. The total high-rate telemetry data lost has
been 32 minutes, and the good data capture rate is at 97.3%.
_ _____ _
| | | __ \ | | Ron Baalke | baalke@mars.jpl.nasa.gov
| | | |__) | | | Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
___| | | ___/ | |___ M/S 301-355 |
|_____/ |_| |_____| Pasadena, CA 91109 |
|
| 456.81 | MAGELLAN Update - May 29 | 26523::KLAES | The Universe, or nothing! | Wed May 30 1990 14:13 | 82 |
| Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 05/29/90
Date: 30 May 90 02:30:38 GMT
Reply-To: baalke@mars.jpl.nasa.gov (Ron Baalke)
Organization: Jet Propulsion Laboratory, Pasadena, CA.
Magellan Status Report
May 29, 1990
The Magellan spacecraft is now 106,287,907 miles from Earth,
11,000,297 miles from Venus, and traveling at a heliocentric velocity
of 74,455 mph. The spacecraft is has completed a 27 orbit simulated
Cruise Mapping Test.
Part 3 Orbits #13 through #20
This section covers Orbits #13 of the Cruise Mapping Test which
began at 5:38:58 AM PDT on Wednesday, May 23, through Orbit #20 which
ended at 8:18:58 AM on Thursday, May 24.
The Magellan spacecraft continues to perform nominally during all
simulated orbits. Each star calibration of the 8 orbits discussed
during the reporting period were successful with an average per orbit
update of 0.017 degrees. Momentum wheel desaturations were performed
on Orbit #15 and Orbit #18. The red alarm for the solar panel's Sun
loss sensor was disabled for the rest of the Cruise Mapping Test as
planned, and the solar panels continue to unwind during each mapping
pass. No new red alarms have occurred.
The Radar Team reports that the Radar system is performing
nominally and no alarms have been seen. Out of 13 acquisitions, 13
met the 1 minute criteria. In all cases where the one minute
acquisition was met, good radar data was assumed at the Maximum
Likelihood Convolutional Decoder (MCD) in-lock time to better indicate
actual Deep Space Network (DSN) performance. The DSN is not committed
to a one-minute acquisition in the one-way mode. The first acquisition
was significantly delayed due to an unexpectedly large temperature
induced frequency offset. Incorporation of this effect should allow
one-way acquisitions in the one to three minute range.
Total scheduled Two-Way High-Rate Telemetry Data = 1938 minutes
Total Two-Way High-Rate Telemetry Data Lost = 37 minutes
Good Two-Way Data Capture Rate = 98.1%
Part 4 Orbits #21 through #27
This section covers Orbits #21 of the Cruise Mapping Test which
began at 8:18:58 AM PDT on Thursday, May 24, through Orbit #27 which
ended at 7:38:58 AM on Friday, May 25.
The spacecraft continues to perform flawlessly during all
simulated orbits. Each star calibration of the 7 orbits discussed
during the reporting period were successful with an average per orbit
update of 0.020 degrees. Momentum Wheel Desaturations were performed
on Orbits #21, 24, 27. The cruise 23-2 sequence was successfully
uploaded during Orbit #22, the first such upload without verifying the
DSN's signal acquisition prior to transmission. Thus, the upload
verified the capability to uplink the new sequence while the
spacecraft is on Earth point, and to continue mapping without
interruption. After Orbit #25, the C23-1 sequence was cancelled as
planned. Orbit #26 executed a successful radiometer calibration and
Orbit #27 validated by execution the apoapsis occultation mapping
strategy. No red alarms have occurred.
The Radar Team reports that the Radar system is performing
nominally and no alarms have been seen. Out of 13 acquisitions, 13
met the 1 minute criteria. In all cases where the one minute
acquisition was met, good radar data was assumed at the MCD in-lock
time to better indicate actual DSN performance. The first acquisition
was delayed due to an incorrect calculation of the necessary frequency
offset to predictions.
Total scheduled Two-Way High-Rate Telemetry Data = 2679 minutes
Total Two-Way High-Rate Telemetry Data Lost = 65 minutes
Good Two-Way Data Capture Rate = 97.6%
_ _____ _
| | | __ \ | | Ron Baalke | baalke@mars.jpl.nasa.gov
| | | |__) | | | Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
___| | | ___/ | |___ M/S 301-355 |
|_____/ |_| |_____| Pasadena, CA 91109 |
|
| 456.82 | MAGELLAN Update - June 4 | 26523::KLAES | The Universe, or nothing! | Tue Jun 05 1990 20:04 | 40 |
| Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 06/04/90
Date: 4 Jun 90 21:25:27 GMT
Reply-To: baalke@mars.jpl.nasa.gov (Ron Baalke)
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
June 4, 1990
The Magellan spacecraft is operating nominally in cruise mode
following completion of a successful cruise mapping test on Friday,
May 25. On completion of the final "orbit" of the mapping test, the
radar was turned off and the spacecraft subsystems were returned from
orbital operations to cruise configuration.
Last week's star calibrations were all successful with an average
daily attitude update of 0.09 degrees.
Solar panel output now exceed 1000 watts as the spacecraft
continues to approach the Sun and Venus. Cruise sequence load 24 was
uploaded last Friday.
The spacecraft is 108 million miles from Earth and 10.5 million
miles from Venus today. Heliocentric velocity is 76,000 miles per
hour. One way light time is 9 minutes and 39 seconds.
SPACECRAFT
Distance from Earth (mi) 108,000,587
Velocity Heliocentric 76,238 mph
One-way light time 9 mins, 39 secs
_ _____ _
| | | __ \ | | Ron Baalke | baalke@mars.jpl.nasa.gov
| | | |__) | | | Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
___| | | ___/ | |___ M/S 301-355 |
|_____/ |_| |_____| Pasadena, CA 91109 |
|
| 456.83 | MAGELLAN Update - June 11 | 26523::KLAES | The Universe, or nothing! | Tue Jun 12 1990 15:53 | 40 |
| Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 06/11/90
Date: 11 Jun 90 21:51:17 GMT
Reply-To: baalke@mars.jpl.nasa.gov (Ron Baalke)
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
June 11, 1990
The Magellan spacecraft is operating nominally in cruise mode
just 60 days away from Venus Orbit Insertion (VOI). Last week saw
the successful upload and initiation of Cruise Sequence 24.
All seven star calibrations during the week were fully
successful, with an average daily attitude update of 0.17 degrees.
A review of all closed VOI action items was held with the project
manager at JPL and the orbit insertion computer command sequence was
frozen; the spacecraft's software is now set to put Magellan into
orbit around Venus.
The Magellan spacecraft is 110 million miles from Earth today,
and little more than 10 million miles from Venus, traveling at 78,325
miles per hour relative to the Sun. One-way light time is 9 minutes,
53 seconds.
SPACECRAFT
Distance from Earth (mi) 110,470,986
Velocity Heliocentric 78,325 mph
One-way light time 9 mins, 53 secs
_ _____ _
| | | __ \ | | Ron Baalke | baalke@mars.jpl.nasa.gov
| | | |__) | | | Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
___| | | ___/ | |___ M/S 301-355 |
|_____/ |_| |_____| Pasadena, CA 91109 |
|
| 456.84 | MAGELLAN Update - June 19 | 26523::KLAES | The Universe, or nothing! | Wed Jun 20 1990 15:05 | 43 |
| Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 06/19/90
Date: 19 Jun 90 22:55:50 GMT
Reply-To: baalke@mars.jpl.nasa.gov (Ron Baalke)
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
June 19, 1990
The Magellan spacecraft continues to cruise and perform nominally
51 days prior to encounter with Venus. Six of the seven daily star
calibrations were fully successful last week in spite of increased
solar activity. The average daily attitude update was 0.05 degrees.
The foreground/background filter successfully rejected several
spurious interrupts on June 9 and 10, and aided the star scanner unit
to pick up the correct star pairs both days.
The week was capped with a very successful test of the personnel,
the software, and the command sequences required to recover the random
access memory safing within 10 hours of orbit insertion. The breadboard
test showed recovery from its intentional safing configuration and
successful orbit insertion.
The spacecraft is now 113 million miles from Earth and has closed
to within less than 10 million miles from Venus. Its heliocentric
velocity is more than 80,000 miles per hour. One way light time, as
of Monday, was 10 minutes and nine seconds.
SPACECRAFT
Distance from Earth (mi) 113,888,559
Velocity Heliocentric 80,630 mph
One-way light time (6/18/90) 10 mins, 9 secs
_ _____ _
| | | __ \ | | Ron Baalke | baalke@mars.jpl.nasa.gov
| | | |__) | | | Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
___| | | ___/ | |___ M/S 301-355 |
|_____/ |_| |_____| Pasadena, CA 91109 |
|
| 456.85 | MAGELLAN Update - July 11 | 26523::KLAES | The Universe, or nothing! | Thu Jul 12 1990 16:39 | 33 |
| Date: 11 Jul 90 20:22:25 GMT
From: (Ron Baalke)
Subject: Magellan Update - 07/11/90
MAGELLAN STATUS REPORT
July 11, 1990
The Magellan spacecraft is progressing toward its insertion into
Venus orbit August 10, 30 days and about 8 million miles away.
All star calibrations during the past week were executed
perfectly yielding an average attitude update of only 0.058 degrees.
The concern over heat has been essentially eliminated with
predictions for maximum temperatures now below established redline
limits. Testing of the new sequence called "Mini-Controller," the
sequence which starts the Venus Orbit Insertion (VOI) block, was
successfully completed in the System Verification Laboratory.
SPACECRAFT
Distance from Earth (mi) 125,919,167
Velocity Heliocentric 84,500 mph
One-way light time 11 mins, 10 secs
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
|
| 456.86 | MAGELLAN Update - July 17 | 26523::KLAES | The Universe, or nothing! | Mon Jul 23 1990 22:17 | 89 |
| Date: 17 Jul 90 20:44:57 GMT
From: (Ron Baalke)
Subject: Magellan Update - 07/17/90
MAGELLAN STATUS REPORT
July 17, 1990
The Magellan spacecraft continues its journey toward its
rendezvous with Venus on August 10, 24 days away. All star
calibrations during the past week were picture perfect resulting
in an average attitude update of 0.06 degrees.
The spacecraft is very stable thermally. Temperatures appear to
have leveled off and the spacecraft is cooling. A special thermal
maneuver will not be required.
Testing of the preliminary Cruise 27 computer sequence, which
contains the Venus orbit insertion maneuver, has begun in the
verification laboratory.
On Friday July 20, at 5 p.m. PDT, the Moon and Venus will be seen
in the eastern sky with Venus appearing one Moon diameter to the
right, with Magellan just 5 million miles behind it.
SPACECRAFT
Distance from Earth, miles 129,638,457
kilometers 208,632,872
Distance to Venus, miles 5,736,902
kilometers 9,232,649
Velocity Heliocentric 86,038 mph
139,382 kph
One-way light time 11 mins, 36 secs
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
Date: 20 Jul 90 18:24:19 GMT
From: (Ron Baalke)
Subject: Corrected Magellan Update - 07/17/90
MAGELLAN STATUS REPORT (corrected)
July 17, 1990
This corrects an error in the 4th graf: changes 5 p.m. to 5 a.m. PDT
for the Moon and Venus sky positions.
The Magellan spacecraft continues its journey toward its
rendezvous with Venus on August 10, 24 days away. All star
calibrations during the past week were picture perfect resulting in an
average attitude update of 0.06 degrees.
The spacecraft is very stable thermally. Temperatures appear to
have leveled off and the spacecraft is cooling. Magellan team members
say that a special thermal maneuver will not be required.
Testing of the preliminary Cruise 27 computer sequence, which
contains the Venus orbit insertion maneuver, has begun in the
verification laboratory.
On Friday July 20, at 5 a.m. PDT, the Moon and Venus will be seen
in the eastern sky with Venus appearing one Moon diameter to the
right, with Magellan just 5 million miles behind it.
SPACECRAFT
Distance from Earth, miles 129,638,457
kilometers 208,632,872
Distance to Venus, miles 5,736,902
kilometers 9,232,649
Velocity Heliocentric 86,038 mph
139,382 kph
One-way light time 11 mins, 36 secs
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
|
| 456.87 | MAGELLAN's mission and its target planet | 26523::KLAES | The Universe, or nothing! | Mon Jul 23 1990 22:55 | 127 |
| APn 07/23 1308 Magellan-Venus
By LEE SIEGEL
AP Science Writer
PASADENA, Calif. (AP) -- A bedeviled, beleaguered NASA is hoping the
Magellan spacecraft's rendezvous with Venus next month will provide our
best look yet at Earth's hellishly hot neighbor.
If all goes according to plan, the $413 million unmanned device,
centerpiece of a $744 million mission, will orbit the cloud-shrouded
planet on Aug. 10 after a 15-month journey from Earth. And NASA
desperately wants everything to go according to plan.
"This thing must succeed because of the Hubble Space Telescope effect
and the generally bad impression we've all been getting of how NASA has
been conducting its affairs lately," said Steve Saunders, the Magellan
project's chief scientist.
But those setbacks -- the crippling of the $1.5 billion Hubble
observatory due to mirror imperfections; the temporary grounding of the
space shuttles due to hydrogen fuel leaks -- have not dimmed the agency's
enthusiasm for Magellan.
"We've dreamed about the sights we would see. Now it's about to
happen," said Phil Allin, a Magellan project official at the National
Aeronautics and Space Administration's Jet Propulsion Laboratory.
Named for 16th century explorer Ferdinand Magellan, the craft's radar
will penetrate acid-laden Venusian clouds to make pictures and maps 10
times more detailed than the best previous images.
That will help geologists understand forces that sculpted Venus to
create flat lowlands, hilly plains and continent-like highlands capped by
peaks such as 35,400-foot Mount Maxwell, which is a mile taller than
Earth's Mount Everest.
NASA says Magellan's radar will reveal unprecedented details of the
planet's terrain, a landscape shaped by meteorite craters, tens of
thousands of volcanoes, and perhaps movements of gargantuan blocks of the
planet's crust -- a process that may be similar to continental drift on
Earth.
The 3.7-ton spacecraft also will look for ancient shorelines and
channels to learn if Venus once had oceans and rivers, before its carbon
dioxide atmosphere trapped the sun's heat in a runaway "greenhouse effect."
Such global warming makes modern Venus a bone-dry, 900-degree
Fahrenheit oven with an atmospheric pressure 90 times greater than Earth's.
Magellan's mission "is the capstone of the exploration of the inner
planets," said Jim Head, a member of the Magellan science team and a
geologist at Brown University in Providence, R.I.
"We've seen the surfaces of the moon, Mars, the Earth and Mercury, but
Venus always has been obscured by the clouds and we've never gotten a
good global view of it."
The 21-foot-long Magellan was released from the cargo bay of space
shuttle Atlantis on May 4, 1989, then launched on its roundabout, 806
million-mile voyage by an inertial upper-stage rocket.
At 9:31 a.m. PDT on Aug. 10, Magellan will fire its solid-fueled
Star rocket to slow down and go into a elliptical, nearly polar orbit
that ranges from 171 miles to almost 5,000 miles above Venus.
After a few weeks of tests, the spacecraft will bounce radar waves off
Venus to make pictures and topographic maps of 70 percent to 90 percent
of the surface. Meanwhile, the planet will rotate once on its axis
during a single Venusian day, which equals 243 Earth days.
"It's going to give us a map of Venus that in many ways is better than
anything we have for the whole Earth," where most of the ocean floor
hasn't been mapped in detail, Saunders said.
If scientists are lucky, Magellan may tell them if Venusian volcanoes
are active, if movements of the planet's crust produce "Venus quakes,"
and if those movements are more like Earth's drifting continents or like
the upward boiling of molten rock that created Hawaii.
Venus is the planet most like Earth in terms of size, density and
mass, and also is Earth's nearest neighbor, other than the moon. Yet its
clouds prevent the surface from being seen by telescopes or optical
cameras aboard orbiting spaceships.
About 20 spacecraft have visited Venus since the early 1960s, some
deploying landers that photographed small parts of the surface. Pictures
also were made by transmitting radar waves from Earth, and from NASA's
Pioneer Venus orbiter in 1978 and the Soviet Union's Venera 15 and 16
orbiters in 1983.
But the best radar pictures until now could distinguish only those
landscape features wider than about 1 1/4 miles. Saunders said
Magellan's pictures will be roughly 10 times better, capturing features
as small as 260 yards, about the length of 2 1/2 football fields.
Magellan will take 3 hours and 11 minutes to orbit Venus once. During
each orbit, Magellan will spend 37 minutes as it moves from north to
south bouncing radar off a swath of Venus' surface about 10,000 miles
long but only 16 miles wide. The information will be stored on two tape
recorders.
During the rest of each orbit, Magellan will radio the information
back to Earth, where it will be received by 230-foot-wide, dish-shaped
antennas at NASA's Deep Space Network stations in California, Spain and
Australia.
Computers at Jet Propulsion Laboratory will assemble the data into
pictures and topographic maps of each swath. The swaths -- nicknamed
"noodles" because they are so long and narrow -- then will be assembled
into pictures covering larger areas of the planet.
"Mapping a whole new planet will return an enormous amount of data
that will keep geologists busy for a long time," Saunders said. "If you
printed it in books, it would fill a shelf about 10 miles long. It's
very humbling."
Magellan's main 243-day mapping mission will miss the south polar
regions. NASA is expected to approve more 243-day mapping cycles. A
total of three are needed to map the entire planet.
Cost of the Magellan mission through the first 243-day mapping cycle
is $744 million, including the cost of launching the spacecraft from the
shuttle, said Bill Dimmer of NASA's comptroller's office in Washington.
The spacecraft and its instruments account for $413 million of that
total, he said.
|
| 456.88 | MAGELLAN Update - July 23 | 26523::KLAES | The Universe, or nothing! | Wed Jul 25 1990 14:11 | 37 |
| Date: 23 Jul 90 22:41:03 GMT
From: (Ron Baalke)
Subject: Magellan Update - 07/23/90
MAGELLAN STATUS REPORT
July 23, 1990
One of the Magellan spacecraft's gyroscopes, which had previously shown
erratic behavior, appeared to have experienced an electrical failure when
it was turned on last Friday, July 20. The gyro was immediately turned off.
Gyros are used on Magellan to maintain attitude control, and two gyros
are needed to maintain attitude control in all three axes. The faulty gyro
was in the backup pair which were being turned on for the last Trajectory
Course Maneuver (TCM) scheduled for Wednesday July 25, and for Venus Orbit
Insertion (VOI) on August 10.
With the failed gyro now turned off, the remaining spare will be used
as backup. The combination of the two operative gyros in conjunction with
the remaining spare still provides complete operational redundancy in all
three axes of attitude control, and no problems are anticipated during the
TCM or VOI.
The Ground Data System test program continues on schedule. A total of
six Combined System Tests (CST) with playback from the spacecraft recorder
through the (DSN) Deep Space Network, Space Flight Operations Center (SFOC)
and Project subsystems have been successfully performed. Also, a one-second
error in the timing of radar data acquisition during the Cruise Mapping Test
has been corrected.
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
|
| 456.89 | MAGELLAN Update - July 26 | 26523::KLAES | All the Universe, or nothing! | Fri Jul 27 1990 13:46 | 39 |
| Date: 26 Jul 90 17:23:10 GMT
From: (Ron Baalke)
Subject: Magellan Update - 07/26/90
MAGELLAN STATUS REPORT
July 26, 1990
The Magellan spacecraft successfully executed its third and final
Trajectory Correction Maneuver (TCM) yesterday. It is to go into Venus
orbit on August 10. From there it will go into a 22 day checkout and
is scheduled to start Venus mapping on August 31.
The spacecraft's small 0.2 pound thrusters pulsed for five
minutes and 21 seconds for a scheduled change of Magellan's velocity
by 0.749 meters per second, a very small fraction of a mile per hour.
The actual change, however, was 0.685 meters per second, an 8.5 percent
shortfall, but well within the tolerances expected of the planned burn.
The TCM also moved very slightly the spacecraft's aim point.
SPACECRAFT
Distance from Earth, miles 135,319,165
kilometers 217,775,085
Distance to Venus, miles 3,662,425
kilometers 5,894,103
Velocity Heliocentric 86,243 mph
139,714 kph
One-way light time 12 mins, 3 secs
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
|
| 456.90 | MAGELLAN Updates - July 26-27 | 26523::KLAES | All the Universe, or nothing! | Mon Jul 30 1990 14:45 | 104 |
| From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 07/26/90
Date: 26 Jul 90 17:23:10 GMT
Reply-To: baalke@mars.jpl.nasa.gov (Ron Baalke)
MAGELLAN STATUS REPORT
July 26, 1990
The Magellan spacecraft successfully executed its third and final
Trajectory Correction Maneuver (TCM) yesterday. It is to go into Venus
orbit on August 10. From there it will go into a 22 day checkout and
is scheduled to start Venus mapping on August 31.
The spacecraft's small 0.2 pound thrusters pulsed for five
minutes and 21 seconds for a scheduled change of Magellan's velocity
by 0.749 meters per second, a very small fraction of a mile per hour.
The actual change, however, was 0.685 meters per second, an 8.5
percent shortfall, but well within the tolerances expected of the
planned burn. The TCM also moved very slightly the spacecraft's aim
point.
SPACECRAFT
Distance from Earth, miles 135,319,165
kilometers 217,775,085
Distance to Venus, miles 3,662,425
kilometers 5,894,103
Velocity Heliocentric 86,243 mph
139,714 kph
One-way light time 12 mins, 3 secs
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
Date: 29 Jul 90 06:31:58 GMT
From: (Ron Baalke)
Subject: Magellan Update - 07/27/90
Magellan Status Report
July 27, 1990
The Magellan spacecraft is now 135,950,482 miles from Earth,
3,423,307 miles from Venus and traveling at a heliocentric velocity of
86,211 mph. One way light time is 12 minutes 10 seconds. Magellan
passed spacecraft perihelion at 8:32PM (PDT) on July 23 and is now
slightly inside the orbit of Venus, and will arrive at Venus on August 10.
The Venus Orbit Insertion (VOI) "Earthquake Contingency Plan" was
completed on July 21, with the storing of contigency VOI command
sequences at the three Deep Space Network (DSN) tracking complexes.
This plan protects the VOI for Magellan in the event of a catastrophic
loss of command capability at JPL.
Some more information about the failed gyroscope. The Magellan
Attitude Control System contains two inertial Attitude Reference Units
(ARU) designated A and B. Each ARU contains two gyroscopes,
designated 1 and 2, and each provides two channels capable of
measuring position errors about two spacecraft axes.
Gyro A-1 --> Provides X and Z axis errors
Gyro A-2 --> Provides X and Y axis errors
Gyro B-1 --> Provides Y and Z axis errors
Gyro B-2 --> Provides X and Y axis errors
On October 2, 1989, gyro B-2 exhibited a failure that was
diagnosed as a dynamic instability in the bearing retainer chatter,
and ARU B was powered down. ARU B was powered up on July 20, 1990 to
see if the gyro B-2 could be used for VOI. The motor was running well
but the channel outputs (X and Y axes) were saturated and never
varied. Gyro B-2 was then powered off on July 20.
The cause fo the failure in gyro B-2 is under investigation.
There are several plausible electronic failures that would cause the
symptons. A decision was made to leave gyro B-1 powered up, along with
ARU A (gyros A-1 and A-2) for VOI. Gyro B-2 will remain powered down.
The original purpose of using both ARU's during VOI was that
triple- redundancy was available about the spacecraft's X and Y axes,
the major Solid Rocket Motor (SRM) control axes. This enabled very
fast, direct detection of a failed gyro. The present configuration is
dual-redundant and gyro failures are detected indirectly through
vehicle dynamics with fault protection, which takes longer.
It should be noted that the Magellan design of four gyros is
unique for planetary spacecraft. Previous spacecraft designs used
only three gyros. The fault protection functions now on Magellan with
the three gyros, involves a risk similiar to other planetary orbit
insertions.
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
|
| 456.91 | MAGELLAN Update - July 30 | 26523::KLAES | All the Universe, or nothing! | Tue Jul 31 1990 14:15 | 52 |
| Date: 30 Jul 90 23:55:45 GMT
From: (Ron Baalke)
Subject: Magellan Update - 07/30/90
MAGELLAN STATUS REPORT
July 30, 1990
Just 11 days from Venus Orbit Insertion (VOI), the Magellan
spacecraft is functioning nominally after a successful third
Trajectory Correction Maneuver last Wednesday, July 25. The TCM
occurred precisely on time and achieved a velocity change of 0.7
meters per second, within 6.5 percent of the planned maneuver.
On Friday, July 20, an electronic problem was discovered in one
of the two back-up gyros when the pair, B1 and B2, were turned on in
preparation for VOI. B1 came up nominally and remains working well. B2
showed evidence of a problem and was turned off. In-flight trouble
shooting of the gyro will not be done until after VOI.
The Cruise 26 Command Sequence, containing the TCM, was uplinked
on July 23 after completion of successful testing in the System
Verification Laboratory. There was one hit during uplink transmission
and part of the load had to be re-transmitted. Several other command
loads were transmitted during the week with no difficulty.
The Cruise 26 sequence also changed the reference star pair to
Canopus and Aldebaran on July 26. The star calibrations for the week
were all successful with an average attitude update of 0.09 degrees.
Also concerns over spacecraft heating have lessened for VOI since
Magellan passed through perihelion on July 21. All temperatures have
either stabilized or are actually starting to drop. The spacecraft is
in excellent condition and ready for VOI.
SPACECRAFT
Distance from Earth, miles 137,838,433
kilometers 221,829,454
Distance to Venus, miles 2,701,228
kilometers 4,347.206
Velocity Heliocentric 86,050 mph
137,000 kph
One-way light time 12 mins, 20 secs
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
|
| 456.92 | MAGELLAN Update - August 4 | ADVAX::KLAES | All the Universe, or nothing! | Tue Aug 07 1990 14:09 | 57 |
| Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 08/04/90
Date: 6 Aug 90 15:42:01 GMT
Reply-To: baalke@mars.jpl.nasa.gov (Ron Baalke)
Magellan Status Report
August 4, 1990
The Magellan spacecraft is now 140,802,000 miles from Earth,
1,490,768 miles from Venus and traveling at a velocity of 10,100 mph
relative to Venus. One way light time is 12 minutes 37 seconds.
Magellan Venus Orbit Insertion (VOI) will occur on August 10,
just 6 days away. Cruise 27 began today and the VOI commands were
uplinked up to the Attitude and Articulation Control Subsystem (AACS).
Magellan will become the first US spacecraft to go into planetary
orbit since Pioneer Venus entered Venus orbit in 1978. Pioneer Venus,
incidently, is still orbiting Venus. The following chart shows
Magellan's approach distance and velocity to Venus.
APPROACH
DATE/TIME DISTANCE TO VENUS VELOCITY ONE WAY LIGHT TIME
------------------ ----------------- ---------- ------------------
8-4 (9:00 AM PDT) 1,490,768 miles 10,100 mph 12 min 37 sec
8-6 (9:00 AM PDT) 1,005,783 miles 10,114 mph 12 min 43 sec
8-8 (9:00 AM PDT) 519,095 miles 10,189 mph 12 min 50 sec
8-9 (9:00 AM PDT) 273,113 miles 10,343 mph 12 min 53 sec
8-10 (9:00 AM PDT) 10,689 miles 16,992 mph 12 min 56 sec
8-10 (VOI BURN, 9:32) 24,600 mph Spacecraft Occulated
8-10 (AFTER BURN, 9:34) 18,675 mph Spacecraft Occulated
Magellan is approaching Venus from above its northern pole on a
hyperbola path. On August 10 at 9:28 AM (PDT) the spacecraft will
enter the Earth Occulation Zone, meaning the spacecraft will have
passed behind Venus and out of radio contact with Earth. At 9:32 AM
the Solid Rocket Motor (SRM) will burn for 83 seconds to impart a
velocity change of 2.7 kilometers/second, to slow the spacecraft from
24,600 mph to 18,675 mph. Magellan will make its closest approach at
9:37 AM just 275 kilometers from the planet, at 10 degrees north
latitude at a 86 degree inclination. At 9:53 AM (Earth receive time -
10:06 AM), Magellan will exit the Earth Occulation Zone and radio
contact with the spacecraft will be re-established. If for some
reason the SRM burn does not occur, the spacecraft will appear from
behind Venus 5 minutes earlier than expected at 9:48 AM (Earth receive
time - 10:01 AM), and will proceed to fly on by Venus. We do not want
see Magellan make an early appearance. It has been determined that if
four of the eight engines on the SRM fails, there is still a 90%
chance of the VOI of being successful. The SRM burn will place
Magellan into a polar orbit of 3.15 hours around Venus.
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
|
| 456.93 | How MAGELLAN will radar-map Venus | ADVAX::KLAES | All the Universe, or nothing! | Tue Aug 07 1990 14:45 | 93 |
| UPn 08/06 0019 Probe to study Venus with radar
By WILLIAM HARWOOD
UPI Science Writer
CAPE CANAVERAL, Fla. (UPI) -- NASA's Magellan probe, cobbled together
from spare parts left over from other programs, will use radar beams to
create a detailed, photo-quality map of cloud-shrouded Venus's hidden
surface.
Launched May 4, 1989, from the shuttle Atlantis, Magellan is to slip
into orbit around Venus early Friday after a 15-month space voyage.
Its goal: To spend at least 243 days mapping the cloudy planet's
hidden surface using a high-resolution radar capable of distinguishing
objects as small as a football field.
Built by Martin Marietta Astronautics Co. of Denver, Magellan will be
placed in a highly elliptical three-hour, nine-minute orbit around Venus,
one tilted 86 degrees to the equator with a low point of about 170 miles
and a high point of about 5,000 miles.
As the probe travels through the low-altitude part of each orbit, its
12-foot dish antenna will be used to fire radar pulses at the ground,
"illuminating" a 15.5-mile-wide, 9,900-mile-long swath, or "noodle."
After each 37.2-minute mapping run, Magellan will re-orient itself,
pointing the antenna toward distant Earth so the recorded radar data can
be beamed back to the Jet Propulsion Laboratory in Pasadena, Calif., for
analysis.
The probe then will swing back around, aim its antenna at Venus and
make another mapping pass.
As Magellan sails through the low-point of its orbit, 26.5-millisecond
radar pulses will be fired at the surface at the speed of light, 186,000
miles per second. After a very short but measurable delay, the pulse's
reflection from the surface will be detected by the spacecraft.
By measuring the time between the pulse and the arrival of its
reflection, computers can determine the distance to the point on the
ground where the pulse was reflected. But that alone is not enough to
assemble a map, because more than one point will lie at any given
distance from the spacecraft.
To further pin down a point's location, Magellan also will measure the
"Doppler shift" of the reflected radar pulse, that is, the amount the radar
beam's wavelength has changed because of the spacecraft's orbital motion.
To anyone present when a fire engine goes past, the pitch of the
siren, which depends on the sound's wavelength, will change.
Likewise, a returning radar pulse will have a slightly different
wavelength based on whether Magellan is approaching a point on Venus or
receding from it.
The Doppler shift, then, provides data about the location of a point
on the surface with respect to Magellan's line of flight.
Each point in the Magellan radar image will thus have a unique
distance and Doppler shift. By carefully combining that data, along with
data giving the precise orientation of the antenna, computers can
assemble a photograph-like map of the surface.
The level of detail that can be distinguished by an imaging radar
system depends on the size of the antenna, just as the performance of
normal telescopes depends on the size of the lens or mirror.
Magellan's antenna is 12 feet wide, but because the spacecraft moves a
considerable distance between the time a radar pulse is emitted and its
reflection is received, the antenna has an "effective" diameter of some
3,000 feet.
For this reason, Magellan is said to be equipped with a "synthetic
aperture radar" system and, under the best possible conditions, surface
features as small as 350 feet or so can be distinguished. The best
previous Venus radar maps have resolutions of about 1 mile.
It would greatly simplify Magellan's mission if the spacecraft could
be fired into a circular orbit around Venus, because the probe's velocity
and altitude would remain constant. But a tight budget forced planners
to settle for a cheaper, less-powerful braking rocket, one that can only
achieve an elliptical orbit.
As it is, Magellan's speed will increase as it approaches the
low-point of its orbit, called periapsis, and decrease as it climbs to a
higher altitude.
With Magellan, the timing of the radar pulses must be constantly
adjusted as the craft speeds along to make sure a transmission does not
interfere with a reflection. It is a tremendously complex task and one
that requires some 950 computer commands per pass to accomplish.
|
| 456.94 | "Hidden" typing errors? | 42653::HAZEL | A town called ... er ... thingy | Thu Aug 09 1990 10:15 | 5 |
| I take it that the words "occulated" and "occulation" in .92 should
really be "occulted" and "occultation", respectively?
Dave Hazel
|
| 456.95 | MAGELLAN Update - August 6 | ADVAX::KLAES | All the Universe, or nothing! | Thu Aug 09 1990 12:24 | 53 |
| Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 08/06/90
Date: 6 Aug 90 22:46:29 GMT
Reply-To: baalke@mars.jpl.nasa.gov (Ron Baalke)
MAGELLAN STATUS REPORT
August 6, 1990
Four days before orbit insertion, the Magellan spacecraft remains
in excellent condition. All star calibrations last week were
successful with an average attitude update of 0.05 degrees. Only one
spurious interrupt was processed, compared with six the previous week.
The temperatures of spacecraft components, which are being
watched carefully, have all declined since perihelion and remain below
red limits.
Based on recent tracking data, the navigation team's best
solution for the July 25 trajectory correction maneuver was 0.69
meters per second, which was 7.2 percent under the planned velocity
change, but within the required tolerance for Venus Orbit Insertion.
The time of the solid rocket motor burn was advanced from 9:45:29 PDT
to 9:32:09 PDT (Earth receive times) and the delta velocity was
increased by 0.2 meter per second.
The Cruise 27 command sequence containing the VOI maneuvers was
uplinked last Friday. Two sequence inconsistencies were discovered.
The first was that the VOI block would override the Cruise 26 sequence
for momentum wheel desaturation before the last Cruise 26 desat. The
other sequence problem relates to the tape recorder commands after
VOI. The current sequence would leave 17 hours of engineering data
unrecorded on Aug. 12. Ways to correct the problems were being
investigated.
SPACECRAFT
Distance from Earth, miles 142,183,448
kilometers 228,822,079
Distance to Venus, miles 1,005,783
kilometers 1,618,651
Velocity Heliocentric 85,334 mph
138,241 kph
One-way light time (7a.m.PDT) 12 mins, 33 secs
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
|
| 456.96 | MAGELLAN's Venus radar mapping schedule | ADVAX::KLAES | All the Universe, or nothing! | Thu Aug 09 1990 16:41 | 35 |
| Date: 6 Aug 90 18:42:36 GMT
From: usc!elroy.jpl.nasa.gov!jato!mars!baalke@ucsd.edu (Ron Baalke)
Subject: Re: Magellan Update - 07/30/90
In article <3169@wrgate.WR.TEK.COM> dant@mrloog.WR.TEK.COM (Dan
Tilque) writes:
>One of the interesting features of Magellan is that it has only one
>high gain antenna. This antenna will be used for both radar and
>transmitting the radar images back to Earth. Naturally, the it can't
>be doing both at once and, in fact, has to swivel around between taking
>imagaes and talking to Earth. I'm not sure if VOIR had two antennae
>and that one was dropped, but I suspect that it was.
Once Magellan starts its mapping phase on September 1, it will do
the following on EACH 3.15 hour orbit around Venus:
37.2 min - Mapping
6.0 min - Turn towards Earth
1.0 min - Lockup with Deep Space Network antenna
56.4 min - Playback #1
14.0 min - Star Calibration
1.0 min - Lockup with Deep Space Network antenna
58.0 min - Playback #2
4.6 min - Idle
6.0 min - Turn towards Venus
4.7 min - Idle
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
|
| 456.97 | | 20408::FISHER | Locutus: Fact or Fraud? | Thu Aug 09 1990 20:42 | 4 |
| Let's hope we have better luck continually repointing antennae than Phobos II
did.
Burns
|
| 456.98 | MAGELLAN is in orbit! | ADVAX::KLAES | All the Universe, or nothing! | Fri Aug 10 1990 21:16 | 139 |
| WP 08/10 Magellan May Give NASA a Lift Today; Spacecraft ...
Magellan May Give NASA a Lift Today; Spacecraft Launched 15 Months Ago
Set to Enter Orbit Around Venus
By Kathy Sawyer
Washington Post Staff Writer
Shortly after noon today, the Magellan spacecraft, which left Earth in
May of 1989, is scheduled to fire its rocket for 83 seconds, slide into
orbit around the cloud-shrouded planet Venus, and provide the
problem-plagued U.S. space agency with a bit of good news.
The robot craft will disappear behind Earth's sister planet during the
crucial moments of the maneuver into orbit, a period scientists said
would be nerve-wracking. If the rocket fails to fire, NASA project
manager Anthony J. Spear noted, "we go whizzing by Venus" into an orbit
around the sun and "it would take 100 years before things line up for
another try" at the planet.
Scientists at the Jet Propulsion Laboratory in California, where the
Magellan project is managed, offered a bit of NASA black humor about the
fear of another failure. They said NASA's chief scientist, Lennard Fisk,
jokingly told them he had bought two airline tickets for today - "one to
Los Angeles and one to Tahiti."
"The major pressure we feel is the pressure to succeed," NASA solar
system exploration official Wesley T. Huntress said when asked about the
impact of a series of setbacks in the Hubble Space Telescope and space
shuttle programs.
But as he and others pointed out, "the planetary program is doing
extremely well" and Magellan seems to be performing as ordered.
The 3.7-ton spacecraft was launched on its 948 million-mile trip 15
months ago by the shuttle Atlantis. Its mission, at a cost of $744
million including the launch, is to spend one Venus day - 243 Earth days
- using advanced radar to make the most complete and detailed radar
pictures ever of the cloud-veiled surface.
Scientists want to study Venus, which was formed at about the same
time as Earth, as a model of an Earthlike planet gone wrong, with a
poisonous atmosphere 900 degrees Fahrenheit at the surface, the result of
a runaway "greenhouse effect" that they hope Earth can avoid.
Engineers at JPL received a signal from Magellan Wednesday indicating
that its solid-fuel rocket had been armed.
At 12:32 p.m. EDT today, onboard computers will order the rocket to
fire for 83 seconds, slowing Magellan's velocity from about 25,000-mph to
about 18,600 mph. This will allow it to be captured by Venus' gravity in
a near-polar orbit ranging from 171 miles to almost 5,000 miles above the
planet.
If all goes well, the spacecraft will emerge from Venus's shadow about
12:54 p.m. Since radio signals currently take almost 13 minutes to travel
from Venus to Earth, a signal indicating the $287 million craft is safe
in orbit will reach engineers at 1:07 p.m..
If a signal arrives at 1:02 p.m., five minutes early, this will
indicate the rocket failed, the craft is speeding past the planet and the
mission is a "no go," at least for this century. Copyright 1990 The
Washington Post
APn 08/10 0105 Magellan-Venus
By LEE SIEGEL
AP Science Writer
PASADENA, Calif. (AP) -- The Magellan orbiter, the first U.S.
planetary spacecraft launched since 1978, zoomed toward a rendezvous with
Venus today on a mission to make the most detailed pictures yet of its
rugged surface.
"I'm excited, I'm exuberant, and I'm so delighted I can hardly control
my emotions," said Ed Sherry, a Magellan project official at NASA's Jet
Propulsion Laboratory.
The spaceship was scheduled to fire its braking rocket and drop into
orbit around Venus at 9:32 a.m. today after a roundabout,
948-million-mile trip from Earth that began 15 months ago.
Confirmation wasn't expected until about a half-hour later because the
rocket ignition was to happen when the spacecraft was behind Venus, out
of radio contact with Earth.
As of 9 p.m. Thursday, the craft was traveling at 10,651 mph. It was
147,587 miles from Venus and 144 million miles from Earth.
The $413 million craft was designed to use radar to penetrate Venus'
thick clouds and make maps and pictures of the planet's deformed,
volcanic landscape with unprecedented detail.
NASA plans to release the first pictures in September, but may do so
this month if images made during tests produce any interesting
discoveries.
Magellan has raised NASA's hopes after its recent woes, including the
temporary grounding of the shuttle fleet because of hydrogen leaks and a
defective mirror that crippled the $1.5 billion Hubble Space Telescope.
"The major pressure we feel is the pressure to succeed," Wesley T.
Huntress Jr., NASA director of solar system exploration, said Thursday.
"I'd prefer not to speculate on what failure might mean."
The 21-foot Magellan, deployed from the shuttle Atlantis in May 1989,
was the first U.S. planetary spacecraft launched since 1978, when NASA
sent the Pioneer 12 orbiter and the Pioneer 13 probes to Venus.
"Magellan is the beginning of a new era of planetary exploration,"
Huntress said. "We're looking forward to the drama."
The Voyager probes explored Jupiter, Saturn, Uranus and Neptune
between 1979 and last year, but they were launched in 1977. Galileo,
launched in October, is headed toward a 1995 rendezvous with Jupiter.
During the coming decade or so, NASA also plans to send spacecraft to
explore Mars, the Moon, Saturn, comets and the Sun's polar regions.
NASA has said Magellan would return more data than all previous NASA
missions combined.
Venus is similar to Earth in size, density and position in the solar
system, although a runaway "greenhouse effect" raised its surface
temperature to 900 degrees Fahrenheit, about as hot as a self-cleaning
oven.
NASA wants to learn if the planet's geological processes are similar
to Earth's. Venus has tens of thousands of volcanoes, but no one knows if
any are active.
Magellan was named for the Portuguese explorer Ferdinand Magellan, who
sailed around the world in the early 1500s.
The spacecraft was built by Martin Marietta Corp. and its radar was
built by Hughes Aircraft Co.
UPn 08/10 0025 Magellan set for crucial rocket firing
PASADENA, Calif. (UPI) -- Here is the timeline for NASA's Magellan
probe in entering orbit around Venus (all times in PDT):
Friday, Aug. 10:
--9:28:09 a.m.: Magellan, racing through space at 24,600 mph, sails
over the north pole of Venus and plunges behind the planet as viewed from
Earth.
--9:41:06 a.m.: Radio signals from the spacecraft stop coming into the
Jet Propulsion Laboratory in Pasadena.
--9:32:09 a.m.: Magellan's solid-fuel braking rocket, built by Thiokol
Corp. of Ogden, Utah, fires to slow the probe by about 6,000 mph to some
18,542 mph.
--9:33:32 a.m.: The rocket motor stops firing. Magellan now is in an
egg-shaped orbit tilted 85 degrees to the equator with a low point of
about 170 miles and a high point of about 5,000 miles.
--9:53:24 a.m.: Magellan emerges from behind Venus as viewed from Earth.
--10:06:21 a.m.: Radio signals from Magellan reach ground controllers
at the Jet Propulsion Laboratory, confirming the success of the maneuver.
If the rocket firing fails, Magellan will emerge from behind Venus at
9:48:20 a.m. and signals will be detected on Earth at 10:01:17 a.m., five
minutes earlier than would be expected if the rocket fired properly.
In that case, Magellan would not return to the vicinity of Venus for
more than 100 years.
|
| 456.99 | | STAR::HUGHES | You knew the job was dangerous when you took it Fred. | Sat Aug 11 1990 18:34 | 4 |
| Orbit insertion was successful, with occultation ending on schedule.
Very little propellant was used to correct the SRM firing.
gary
|
| 456.100 | Confirmation from JPL | ADVAX::KLAES | All the Universe, or nothing! | Mon Aug 13 1990 16:31 | 34 |
| Date: 10 Aug 90 18:28:42 GMT
From: (Ron Baalke)
Subject: Magellan Venus Orbit Insertion - Success!!
Title says it all. At 10:06 AM (PDT), we've received Magellan's radio
signal as the spacecraft made it appearance from behind Venus
confirming that the Solid Rocket Moter (SRM) burn was successful, and
that Magellan has achieved Venus orbit.
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
Date: 10 Aug 90 17:36:31 GMT
From: usc!elroy.jpl.nasa.gov!jpl-devvax!leem@ucsd.edu (Lee Mellinger)
Subject: Magellan in Orbit!
At 10:06:27 PDT Magellan was confirmed in orbit around Venus.
Preliminary checks of the spacecraft reveal no major anomalies and
event counter, propellant quantities, temperatures , etc. all indicate
a nominal burn.
Lee
"Mit Pulver und Blei, die Gedanken sind frei."
|Lee F. Mellinger Caltech/Jet Propulsion Laboratory - NASA
|4800 Oak Grove Drive, Pasadena, CA 91109 818/393-0516 FTS 977-0516
|leem@jpl-devvax.JPL.NASA.GOV
|
| 456.101 | MAGELLAN on its first day in orbit | ADVAX::KLAES | All the Universe, or nothing! | Tue Aug 14 1990 13:56 | 217 |
| UPwe 08/13 1503 Magellan probe in good shape
PASADENA, Calif. (UPI) -- Other than a few minor glitches, NASA's
Magellan probe sailed into orbit around cloud-choked Venus in good shape,
officials said Monday, with tests of the spacecraft's critical radar
mapping system on tap later this week.
Capable of showing surface features as small as a football field -- 10
times better than ever before -- Magellan, the centerpiece of a $551
million project to map Venus's hidden surface, dropped into orbit around
the planet Friday after a 15-month voyage from Earth.
James Doyle, a spokesman for the Jet Propulsion Laboratory in
Pasadena, said Monday the spacecraft ended up in a near-perfect orbit
tilted 85.5 degrees to Venus's equator with a low point of 183 miles and
a high point of 5,253 miles.
Engineers had been aiming for an orbit measuring 170 by 5,000 miles.
Given the accuracy of the rocket firing Friday, a "trim burn" to
fine-tune the orbit using Magellan's liquid-fueled maneuvering rockets
will not be necessary.
Otherwise, the spacecraft survived the jarring braking maneuver Friday
in excellent condition with only a few minor glitches.
Over the weekend, engineers tried to figure out what caused a computer
chip in a backup guidance system to perform erratically after the
spacecraft's spent solid-fuel braking motor was discarded Friday night.
"They were getting telemetry that was indicating an intermittent
problem," Doyle said. "It's part of a backup system. It's like having a
stuck traffic signal. This part of the subsystem takes commands and
redirects them to other parts of the spacecraft. They can reroute those
commands. It's not a significant problem at all."
Engineers planned to aim Magellan's high-data-rate main antenna at
Earth Monday to study detailed telemetry from the spacecraft in bid to
find out what caused the original problem, which was not expected to have
any impact on the probe's mission.
"It is not a continuing or significant problem at all," Doyle said.
"Everything else is coming out very well."
Magellan, built by Martin Marietta Astronautics Group of Denver, was
designed to map at least 90 percent of Venus's surface during its planned
243-day mission, photographing features as small as 350 feet across to
revolutionize knowledge about the mysterious planet.
Engineers plan to begin testing the radar imaging system Thursday and
if all goes well, mapping will begin in early September. But if
preliminary tests generate any particularly interesting images, project
officials may decide to release them to the public.
"There's a slim possibility," Doyle said. "If they can get something
within the first couple of days ... they will release it before the end
of the month. They don't want to promise they're going to come out with
an image until they start mapping."
APn 08/11 0119 Magellan-Facts
PASADENA, Calif. (AP) -- Here are some unusual facts about the
Magellan spacecraft and Venus, culled from "The Magellan Venus Explorer's
Guide" and other NASA publications:
--Getting Magellan to Venus required three main engines and two
rockets on the shuttle Atlantis that carried it into Earth orbit, two
rockets on the inertial upper-stage booster that hurled it toward Venus,
and one braking rocket to slow it down for entry into orbit around
Venus. But for 99 percent of Magellan's 948-million-mile trip to Venus,
it cruised without power.
--Venus is named for the Roman goddess of love. It's continent-like
highlands are named after Aphrodite, the Greek love goddess, and Ishtar,
the Baylonian love goddess.
--Temperatures and pressures on Venus are equivalent to conditions
inside a 900-degree Fahrenheit self-cleaning oven 3,000 feet below the
surface of an ocean on Earth.
--Magellan will collect and send to Earth more computerized
information than the combined total from all previous U.S. missions to
other planets.
--After about a dozen years, Magellan will lack enough propellant to
fire its thrusters and maintain its orbit. The orbit will decay and the
spacecraft eventually will plunge into the Venusian atmosphere and burn up.
--When Magellan uses its radar to map Venus' landscape, it will
consume 200 watts of electricity, about the same as a bright floor lamp.
--If Magellan flew over Earth's Mount St. Helens volcano, it could
recognize it as a mountain. The radars on Soviets' Venera 15 and 16
spacecraft, which were launched in 1983, wouldn't be able to distinguish
Mount St. Helens from a meteorite impact crater.
--The Soviet Union named two craters on Venus after teacher Sharon
[?!] McAuliffe and astronaut Judith Resnick, who were among seven crew
members killed when Challenger exploded after liftoff in 1986. Most
Venerean surface features are named after women.
--When Magellan fired its braking rocket to start orbiting Venus on
Friday, the spacecraft experienced a maximum force seven times the force
of gravity on Earth.
--During each orbit around Venus, Magellan will travel about 38,314
miles as an average speed of 12,163 mph.
UPn 08/11 1349 U.S. sends armada into deep space
CAPE CANAVERAL, Fla. (UPI) -- The Magellan Venus radar mapping probe
is the first in a new wave of unmanned U.S. probes bound for the far
corners of the solar system.
The spacecraft that will carry American space exploration into the
21st century are:
--Magellan: Launched May 4, 1989, from the shuttle Atlantis, this
spacecraft arrived in orbit around Venus on Friday. During a minimum
243-day mission, Magellan will map at least 90 percent of the surface of
the cloud-shrouded planet.
--Galileo: Launched Oct. 18, 1989, from Atlantis. Galileo will
spend at least 20 months in orbit around Jupiter and drop a probe into
its atmosphere starting in 1995.
--Cassini: NASA plans to use an unmanned Titan 4 rocket to fire this
probe to Saturn where it will drop a probe into the atmosphere of its
moon, Titan.
--Comet Rendezvous and Flyby: built with Cassini-type hardware, CRAF
will rendezvous with a comet and fire a penetrator into its icy crust.
--Ulysses: A joint project between NASA and the European Space
Agency, Ulysses is scheduled for launch Oct 5 from the shuttle Discovery
to fly over the poles of the sun, the first such mission ever mounted.
--Mars Observer: an economy-class Mars orbiter scheduled for launch
in 1992 atop a commercial Titan 3 rocket.
Here is a list of milestones involving upcoming U.S. interplanetary
missions as currently planned by NASA (in some cases, exact dates have
not yet been determined):
1989:
05/04/1989 - Magellan is launched to Venus from the shuttle Atlantis.
10/02/1989 - Voyager 2 ends a flyby of Neptune, the final planet in a
"grand tour" that began in 1977.
10/18/1989 - Galileo is launched from the shuttle Atlantis.
1990:
02/09/1990 - Galileo flies past Venus at an altitude of 9,300 miles
and heads back toward the first of two flybys of Earth. The "gravity
assist" flybys will boost the probe's speed high enough to reach distant
Jupiter.
08/10/1990 - Magellan slips into orbit around Venus.
09/01/1990 - Magellan begins mapping the surface of Venus.
10/05/1990 - Ulysses is launched from the shuttle Discovery.
12/08/1990 - Galileo flies past Earth at an altitude of 620 miles.
1991:
04/28/1991 - Magellan ends its initial 243-day mapping mission.
10/29/1991 - Galileo flies past an asteroid named Gaspra.
12/??/1991 - Ulysses uses a Jupiter fly-by to send it back toward the sun.
1992:
09/??/1992 - Mars Observer is launched by a Titan 3 rocket.
12/08/1992 - Galileo flies past Earth at an altitude of 186 miles.
1993:
08/??/1993 - Mars Observer goes into orbit around Mars.
08/28/1993 - Galileo flies past asteroid Ida on the way to Jupiter.
1994:
04/??/1994 - Ulysses flies over the south pole of the sun.
11/??/1994 - Ulysses crosses solar equator.
1995:
07/??/1995 - Galileo releases an atmospheric probe.
08/??/1995 - Ulysses flies over the north pole of the sun to conclude
its mission.
08/22/1995 - CRAF is launched by a Titan 4 rocket on a trajectory
toward its cometary target.
12/07/1995 - Galileo brakes into orbit around Jupiter; probe enters
atmosphere.
1996:
04/08/1996 - Cassini is launched by a Titan 4 rocket.
1997:
03/14/1997 - Cassini flies past asteroid 66 Maja.
07/06/1997 - CRAF flies past Earth.
1998:
01/22/1998 - CRAF flies past asteroid 449 Hamburga.
06/13/1998 - Cassini makes a second Earth fly-by.
2000:
02/01/2000 - Cassini uses Jupiter's gravity to bend course toward Saturn.
08/14/2000 - CRAF reaches Comet Kopff.
2001:
07/20/2001 - CRAF fires a small penetrator into the comet's crust.
2002:
10/02/2002 - Cassini goes into orbit around Saturn.
12/12/2002 - CRAF and Comet Kopff make close approach to the sun.
2003:
01/11/2003 - Cassini drops a probe into the atmosphere of Titan.
03/31/2003 - CRAF mission ends.
2006:
12/31/2006 - Cassini mission ends.
|
| 456.102 | MAGELLAN Updates - August 13-16 | ADVAX::KLAES | All the Universe, or nothing! | Thu Aug 16 1990 19:51 | 195 |
| Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 08/13/90
Date: 15 Aug 90 05:38:59 GMT
Reply-To: baalke@mars.jpl.nasa.gov (Ron Baalke)
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
August 13, 1990
The Magellan spacecraft on August 12 and 13 received a new
command sequence, IO/225, which will take it through the week and
includes the command to begin radar tests on Aug. 16. The new command
sequence also will turn the high-gain antenna toward Earth today. The
higher data rate can be used to sort out a problem that surfaced after
the solid rocket motor (SRM) case separation.
After the separation a series of internal command fault
detections were seen in the telemetry which indicated the backup
Attitude and Articulation Control Subsystem (AACS) memory had rejected
commands from the backup Command Data Subsystem (CDS). The precise
cause of the problem was not immediately determined. Project engineers
said more data was needed. Spacecraft control is functioning normally
through the A subsystems, however.
The spacecraft also autonomously swapped from the primary
gyroscope set to the backup after detecting a small change between the
spacecraft's desired and actual pointing direction. That occurred
while Magellan was still occulted by Venus. Later, just after
separation of the SRM case, a second autonomous swap occurred back to
the original gyroscope set.
No faults are believed to exist in any of the three gyros
currently active and the changeovers were believed activated by small
disturbances in the spacecraft attitude due to forces generated by
switching hydrazine thrusters and the SRM case separation.
Tracking since orbit insertion confirms that the spacecraft's
orbit is very close to the target orbit and the project has decided it
will not be necessary to perform a trim maneuver.
Post orbit-insertion tracking data after the first 13 full orbits
indicate Magellan is in orbit with a 3.26 hour period with periapsis
of 294 kilometers (183 miles), and apoapsis at 8,472 kms (5,253
miles). Inclination is 85.5 degrees. Periapsis latitude is 9.879
degrees North.
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 08/14/90
Date: 15 Aug 90 16:38:41 GMT
Reply-To: baalke@mars.jpl.nasa.gov (Ron Baalke)
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
August 14, 1990
An orbit trim for the Magellan spacecraft was scheduled for Aug.
28, if one was required. But no trim is needed and Magellan will begin
mapping Venus on Aug. 29 instead of Sept. 1. The orbit achieved is not
the target orbit, but the expected performance is essentially identical.
Magellan's orbit has a periapsis of 294 km or 183 miles. The
designed orbit was 275 km, or 171 miles. The periapsis location is 9.9
degrees north latitude instead of 10 degrees north and the orbital
period is 3.26 hours instead of 3.18 hours. The inclination is 85.5
degrees. The target was 85.3 degrees.
The High Gain Antenna (HGA) was turned toward Earth on the
morning of August 13 and a check begun on the backup Attitude and
Articulation Control Subsystem (AACS). The system experienced a logic
failure after separation of the Solid Rocket Motor (SRM) and the
computer was reprogrammed to bypass the memory chip in question.
Further reprogramming will occur this week to insure a safe state in
the event future problems show up in the A-side memory. The long term
solution will be to reprogram around this failed memory to restore
operation redundancy.
Successful star calibrations have been achieved. The cruise 27
command sequence operated until 8AM (PDT) on August 13 and the last
two starcals occurring near periapsis lost one star each time. That
was anticipated and contingency star scans were generated.
The first In-Orbit Checkout (IOC) sequence, IO/225, was uploaded
on August 12 and took effect the following morning. It corrects the
mismatch in timing of orbit events.
The project remains on schedule to functionally test the radar on
August 15 and to bounce the radar signal off the planet on Thursday,
Aug. 16, for the first time.
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 08/15/90
Date: 15 Aug 90 20:09:32 GMT
Reply-To: baalke@mars.jpl.nasa.gov (Ron Baalke)
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
August 15, 1990
One way light time to the Magellan spacecraft is 13 minutes and 6
seconds and the Earth to Venus distance is 146 million miles. The
telmetry rate was switched from 40 bps to 1200 bps on August 13.
Magellan Project engineers prepared to turn on the spacecraft's
synthetic aperture radar at 2:19 p.m. PDT today, Earth receive time.
The radar test will begin tomorrow.
Playback of all data from the orbit insertion is completed and
evaluation of that data will continue for the next few days to
establish system performance.
The X-band transmitter-B experienced a spurious shutoff early
today and will be turned on again later today after examination. The
transmitter's power, a traveling wave tube amplifier, shut down and
the project experts turned back to the A system temporarily. The B
system was being used for operations. A spokesman said the tubes will
usually shut off for a time after about 10,000 hours of operation and
the backup system will automatically go on. The B system was used
throughout the cruise to Venus.
The Attitude and Articulation Control Subsystem (AACS) B memory
that failed is being studied by a team of Martin Marietta Corporation and
JPL experts to develop both a short and long term strategy for its use.
Most star calibrations, now occurring once per orbit, are
successful. A few times one star has been rejected because of improper
magnitude, the amount of voltage the scanner reads as it receives
light from the star. This could be due to a calibration error in the
use of the B system star scanner now being used. Stray light from
Venus has interfered with the internal star scanner's self test during
star calibration.
Gyroscope swaps were experienced after Solid Rocket Motor (SRM)
burn and again after SRM separation on August 10. After the SRM burn
it is believed the gyro swapping was due to attitude disturbances at
the time of transition from 100 lb engine control to 0.2 lb thruster
exceeding the position error limit for gyro switching before being
damped out. After SRM separation, the reason for gyro swapping it
believed to be transients due to transfer from high to low gyro rate
change. All gyros are currently operating in a satisfactory condition.
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 08/16/90
Date: 16 Aug 90 17:13:01 GMT
Reply-To: baalke@mars.jpl.nasa.gov (Ron Baalke)
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
August 16, 1990
Each radar unit of the Magellan spacecraft was individually
turned on for a few minutes yesterday and then turned off. All units
were bought on line until the entire A-side radar was on. The radar
was then switched back to standby mode with just the telemetry and
command unit and the stable local oscillator on. Radar tests begin
today, Aug. 16, at 3:30 p.m. PDT when the first signal will be bounced
off the planet's surface.
No problems occurred in the radar turn on test, based on analysis
of real-time data. Further post-test data analysis will accomplish a
more thorough look at the data.
Radar testing during this In-Orbit Checkout (IOC) period will
continue until Aug. 29 when actual mapping of Venus will begin.
One way light time to the spacecraft is 13 minutes and 8 seconds
and the Earth to Venus distance is more than 146 million miles.
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
|
| 456.103 | Shades of Phobos 2 | 15372::LEPAGE | Caught between Iraq & a hard place | Fri Aug 17 1990 15:25 | 6 |
| I've received alarming news through the grapevine about Magellan. I
don't have all the details but JPL has lost contact with the spacecraft
during a mapping session. Stay tuned for more details!
Drew
|
| 456.104 | | PAXVAX::MAIEWSKI | | Fri Aug 17 1990 16:18 | 4 |
| CNN headline news just reported that "sources say that controlers may have
lost contact with the Magellan spacecraft". No more details were given.
George
|
| 456.105 | Latest on Magellan: It doesn't seem fatal | 15372::LEPAGE | Caught between Iraq & a hard place | Fri Aug 17 1990 17:36 | 50 |
|
UPn 08/17 1240 NASA loses touch with Magellan probe
PASADENA, Calif. (UPI) -- The Magellan radar mapping probe, the
centerpiece of a $551 million project to chart the hidden surface of
Venus, stopped transmitting signals to Earth late Thursday, concerned
NASA officials said Friday.
Engineers are hopeful the solar-powered spacecraft is in a
computer-induced state of hibernation because of possible technical
problems encountered late Thursday as Magellan's main antenna was pointed
away from Earth.
The spacecraft may have locked onto the wrong "guide star" during a
procedure to update the computer's knowledge about its orientation in
space, putting the probe into an automatic "safe mode."
Magellan's electronic brain is programmed to begin searching for Earth
if no signals are received for 18 hours. If the probe is indeed in a
safe mode, engineers at the Jet Propulsion Laboratory could expect to
receive a signal at 9:12 p.m. PDT Friday.
If contact is not restored, Magellan would be unable to accomplish its
planned 243-day mission to map the surface of Venus in another major
failure for NASA, already reeling from criticism over the flawed Hubble
Space Telescope and problems with the shuttle program.
JPL spokesman Alan Wood said the 2 1/2-ton spacecraft, which
dropped into orbit around Venus last Friday, had completed its second
radar mapping orbit when contact was lost.
"We lost the signal last night at 8:52 p.m. (PDT)," he said. "It had
made a pass over the planet with the radar and played back the data.
Then it goes into a star search mode. That was at 8:38 last night.
During that period, the antenna is pointed away from Earth.
"At 8:52 p.m., we were supposed to get the signal back and we didn't.
We haven't gotten a signal since."
During each radar mapping orbit, Magellan points its main antenna at
Venus to collect radar data about its surface. After each such mapping
"pass," the spacecraft is supposed to reorient itself and point the
antenna at Earth so radar data, recorded on tape, can be transmitted to
JPL for analysis.
The spacecraft then turns the antenna away from Earth so optical
sensors can look for programmed "guide stars" to update information about
the probe's orientation in space.
Engineers at JPL expected Magellan to resume contact with Earth at
8:52 p.m. PDT Thursday at the completion of the guide star update, but no
signal was received.
Once in a safe mode, "if it doesn't hear from us, it will begin
searching for the Earth with its medium-gain antenna," Wood said. "And
that'll occur at 9:12 tonight. We haven't sent any commands because we
don't know what's the matter and we don't want to make it any worse than
it is."
Prior to the loss of signal, Wood said, Magellan had been operating
flawlessly and "there were no problems at all."
|
| 456.106 | Contact regained! | 8713::J_BUTLER | USAR...and ready... | Fri Aug 17 1990 19:38 | 4 |
| ABC news reported that NASA had regained contact with Magellan.
(1:00 PM Mountain Daylight Time).
John B.
|
| 456.107 | Drama in Pasadena | 19458::FISHER | Locutus: Fact or Fraud? | Mon Aug 20 1990 15:57 | 9 |
| The way I heard it was that JPL was holding a news conference about the problem.
Some speaker was explaining what they thought happened and that they expected
Magellan would start searching for Earth anytime, when someone walked in and
handed him a note saying they had regained contact. Pretty dramatic.
At this point, I have no idea whether they just got fleeting contact or a solid
lock, or whether it was on medium gain only or of they got a high-gain lock.
Burns
|
| 456.108 | More info about what happened | 19458::FISHER | Locutus: Fact or Fraud? | Mon Aug 20 1990 16:10 | 91 |
|
PASADENA, Calif. (UPI) -- Engineers maintained contact with the
Magellan Venus probe Sunday, buoyed by ``exciting'' pictures of the
planet's hidden surface and confident about preventing another radio
blackout like one last week that interrupted testing.
Even with the delay, Magellan science manager Tommy Thompson said
Sunday an admittedly optimistic schedule indicates the spacecraft could
be ready to begin around-the-clock mapping operations as early as Sept.
1.
Project officials scheduled a news conference Tuesday to release
the first radar pictures from Magellan, test images that were taken last
week before a computer glitch threw the probe into a protective state of
hibernation and knocked it out of contact with Earth for more than 14
hours.
``The resolution is good,'' Thompson said of the clarity of the
images. ``We have much more image than what we expected. We originally
hypothesized we'd only get 10 or 11 spots along the orbit. Instead, we
have imagery almost along the entire orbit.''
Magellan uses radar beams to penetrate the clouds that perpetually
blanket Venus. By subjecting the radar data to intensive computer
processing on Earth, scientists can generate photo-like images showing
surface features as small as a football field, 10 times better than any
previous effort.
Thompson would not discuss Magellan's test photos prior to the news
conference Tuesday, saying only, ``We got something exciting.''
But other officials have said the images show volcanos, extensive
lava flows and other violent topology, a hint of the wealth of
revolutionary data Magellan will beam back to Earth during the course of
its $551to work the bugs out of the system and find out what caused
Magellan, which dropped into orbit around Venus Aug. 10, to lose contact
with Earth last Thursday.
Engineers spent the day Sunday sifting through reams of computer
data beamed back to Earth from Magellan after contact was restored
Friday.
Preliminary results indicate three apparently unrelated problems
contributed to triggering various levels of protective hibernation
called ``safe modes.''
Contact was lost shortly after Magellan attempted to find and lock
onto a guide star. Such ``star calibrations'' are part of a routine
procedure to update on-board computers about the spacecraft's
orientation in space.
The safe mode programs apparently were activated when the computer
that controls the spacecraft's attitude suddenly stopped sending routine
timing signals to Magellan's master computer.
This loss of the first computer's ``heartbeat'' prompted the main
computer to put the spacecraft into an initial safe mode called ``RAM
safing.''
The spacecraft immediately stopped what it was doing, aimed its
solar panels broadside to the sun and began to search for the bright
star Sirius. By knowing its position relative to the sun and Sirius,
Magellan would be able to point a radio antenna at Earth to receive
further instructions.
At that point, the second problem occurred: The star sensor,
possibly confused by a dust speck, a bright planet or Venus itself, was
unable to locate Sirius. That, in turn, prevented the probe from finding
Earth.
Magellan's master computer then began executing programs to find
out what was wrong and at some point during that process a third event
took place that triggered a deeper level of protective software.
Magellan then began actively seeking Earth by rotating about its
vertical axis so its radio beam eventually would sweep across the
planet. And that is exactly what happened Friday, allowing engineers to
regain contact.
``They're dealing with three separate problems here,'' JPL
spokeswoman Mary Beth Murrill said. ``They don't know if they're related
in any way. What they have to find first is what caused the heartbeat
loss on the (attitude control computer).''
Article 564 of clari.tw.space
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From: clarinews@clarinet.com
Newsgroups: clari.tw.space,clari.news.urgent
Subject: Engineers study Magellan data
Keywords: space, science, air transport, transportation, air force,
military
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Date: 19 Aug 90 18:47:52 GMT
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|
| 456.109 | Details on the MAGELLAN signal loss from JPL | ADVAX::KLAES | All the Universe, or nothing! | Mon Aug 20 1990 17:03 | 92 |
| Newsgroups: sci.space,sci.astro
Subject: Magellan Special Report - 08/17/90
Date: 17 Aug 90 17:00:54 GMT
Reply-To: baalke@mars.jpl.nasa.gov (Ron Baalke)
Organization: Jet Propulsion Laboratory, Pasadena, CA.
Magellan Special Report
August 17, 1990
A spacecraft emergency has been declared for the Magellan
spacecraft, as contact with the spacecraft has apparently been lost.
Last night, Magellan played back part of its radar data taken earlier
in the day before performing a star calibration. The receiver and
telemetry dropped lock as expected at the 70 meter antenna in
Australia as Magellan went into the star calibration. Fourteen minutes
later the station reported that they did not see the expected signal
in the Spectrum Signal Indicator (SSI), which indicates that the
spacecraft did not turn back to Earth after the star calibration, or
the spacecraft did make the turn but was not transmitting, or the
spacecraft went into safemode. Spacecraft emergency was then declared.
The 70 meter antenna in Spain has extended their Magellan support
through 9:30AM this morning. The 70 meter antenna in Goldstone,
California, was also brought up for emergency support at 3:00AM this
morning. The cause of the signal loss in under investigation. If
Magellan went into safemode, then a downlink will be expected later
tonight from the spacecraft.
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
Newsgroups: sci.space,sci.astro
Subject: Magellan Advisory (Forwarded)
Date: 17 Aug 90 22:35:38 GMT
Reply-To: baalke@mars.jpl.nasa.gov (Ron Baalke)
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN ADVISORY
Magellan spacecraft controllers lost contact with the Venus
mapper late Thursday during the spacecraft's second test-mapping orbit
after it turned to make a star calibration, officials at NASA's Jet
Propulsion Laboratory said.
JPL Magellan Project officials believe the spacecraft has
automatically entered a safing mode after acquiring the wrong guide
star for pointing and will begin searching for Earth direction this
evening.
The spacecraft, which begin testing its imaging radar Thursday
afternoon, turned its antenna to confirm and update it attitude, and
the signal was not reacquired.
The second test orbit started at 10 p.m. EDT. Magellan completed
its radar illumination of the planet's surface and started replay of
the recorded data. It began a star calibration maneuver to confirm
its position.
The signal did not reappear as expected at 11:32 p.m. EDT, 14
minutes later, officials said.
Project officials believe the spacecraft detected a fault and
entered a protective safing mode in which it orients itself toward the
sun so its solar array will continue to receive power and then finds a
guide star. From that position it then turns its medium-gain antenna
toward Earth.
The spacecraft will wait for 18 hours to hear from its
controllers on Earth and if no signal is received it assumes it has
the wrong guide star. It will begin a search pattern to find Earth so
contact can be reestablished.
Project officials said they would wait for the spacecraft to
begin its search for Earth at 12:12 a.m., EDT, Saturday, Aug. 18.
- end -
Note: Contact has been reestablished with the Magellan spacecraft.
Preliminary guesses as to what happened is that stray light
from Venus confused the star scanner unit during the star
calibration.
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
|
| 456.110 | MAGELLAN Update - August 20 | ADVAX::KLAES | All the Universe, or nothing! | Tue Aug 21 1990 17:37 | 56 |
| Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 08/20/90
Date: 20 Aug 90 23:35:50 GMT
Reply-To: baalke@mars.jpl.nasa.gov (Ron Baalke)
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
August 20, 1990
The Magellan spacecraft is stable with its medium-gain antenna
pointed toward Earth. Its solar arrays are pointed toward the sun and
its batteries are fully charged. Both Command Data System (CDS)
computers are operating. The Attitude and Articulation Control
Subsystem (AACS) is executing from Read- Only Memory (ROM) in the A
memory, and the spacecraft is using its hydrazine thrusters for
attitude control.
The project is continuing to perform a series of memory readouts
to diagnose the problem which caused the loss of spacecraft signal
during the second orbit of the radar test on Aug. 16-17. Due to the
low telemetry rate available through the medium-gain antenna at the
present distance from Earth (40 bits per second), the readouts take a
long time and are being carefully synchronized.
Based on the readouts, a good reconstruction can be made of the
sequence of spacecraft events during the loss of signal. There appear
to have been three separate faults:
o Heartbeat loss was detected during the second orbit star
scan (heartbeat is the term used for the continuous process
of checking by the CDS computer on the AACS computer);
o RAM (random-access memory) safing in the AACS-B memory
failed to find the correct guide star (Sirius), and
o AACS began to execute random data in the AACS-B memory
after about 13 hours, causing ROM (read-only memory) safing in
the A-side memory.
There is no evidence yet available to explain the initial
heartbeat loss which started the loss of signal.
The failure to find the guide star was probably due to the star
scanner accepting another bright object as the target star, Whether
this object was a planet, another star, or a dust particle is not yet
known. ROM safing pointed the solar arrays toward the sun and started
Earth coning, moving the spacecraft in a circular sweeping motion to
find Earth.
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
|
| 456.111 | Venus - Volcano Central? | ADVAX::KLAES | All the Universe, or nothing! | Tue Aug 21 1990 18:05 | 87 |
| From: clarinews@clarinet.com
Newsgroups: clari.tw.space
Subject: Scientists excited by Venus pictures
Date: 21 Aug 90 12:13:41 GMT
PASADENA, Calif. (UPI) -- ``Fantastic'' photo-like test images
from the Magellan probe indicate the hidden surface of Venus is
wracked by eruptions and quakes, a ``volcanic swamp'' of lava-filled
valleys and tortured terrain that promises to keep scientists busy for
years to come.
``In the initial processing, we saw a lot of really
interesting features,'' Magellan project scientist Stephen Saunders
said in a telephone interview Monday. ``The stuff that we worked up
initially, we were seeing volcanic depressions of various kinds,
volcanic lava flows and very highly faulted regions that are called
`tessera,' the Latin word for tile.
``It's a very highly deformed, faulted terrain, very rugged.
We've seen that before at much larger scale, and now with Magellan
we're seeing it all the way down to the scale of a few hundred yards.''
While scientists are elated with Magellan's initial results --
the first radar test images from the spacecraft were scheduled to be
released at an afternoon news conference -- engineers at the Jet
Propulsion Laboratory still were not sure what briefly knocked the
spacecraft out of contact with Earth last week.
At least three problems, including a computer glitch and
trouble maintaining the proper orientation in space, derailed
Magellan's three-week test program almost as soon as it got started.
But contact was restored Friday and engineers are optimistic
about fixing the problems and pressing on with Magellan's $551 million
mission to map at least 90 percent of the surface of Venus at 10 times
the resolution, or clarity, of any previous effort.
Saunders said the test data collected last week before contact
was lost were better than expected, giving scientists confidence that
Magellan may be able to help answer fundamental questions about why
Venus, so similar to Earth in so many ways, turned into the 900-degree
inferno it is today.
``I wasn't expecting that kind of performance out of the
thing,'' Saunders said. ``It just seemed like the first test resulted
in such fantastic images. I'm more than satisfied. Everything seems to
have worked just exactly as planned.''
Magellan was designed to ``see'' through the clouds that
perpetually blanket Venus by bouncing radar beams off the planet's
surface. Extensive computer processing on Earth can convert such radar
data into photo-like images showing surface features as small as a
football field.
The solar-powered spacecraft dropped into orbit around Venus
Aug. 10, 15 months after launch from the shuttle Atlantis, and
engineers were in the process of testing its sophisticated radar
system when the probe went into a computer-induced state of hibernation
Thursday that briefly knocked it out of contact with Earth.
But by that time, Magellan had gathered 1 1/2 orbits worth of
radar test data that elated scientists said proves the spacecraft
ultimately will be able to accomplish its 243-day mapping mission.
Saunders said the initial images appear to show ``volcanic
lava flows filling in the valleys. It seems like a big volcanic swamp
(with) molten rock near the surface.''
Earth's surface appears to be made up of giant, slowly moving
continental ``plates'' that make up the planet's crust. The San
Andreas Fault, for example, marks the boundary where the North
American plate plunges under the Pacific Ocean plate.
Saunders said such ``plate tectonics'' appears to work
differently on Venus, a planet with a surface temperature of some 900
degrees and not a trace of water.
``I think the plates, if there are plates, tend to get broken
up a lot easier,'' he said. ``On Earth, they stay rigid ... and
they're only broken on the edges where they grind together. If there
are plates (on Venus), they're kind of squishy, deformal plates.''
Even with the glitches last week, scientists are optimistic
about beginning full-time observations around Sept. 1. In the
meantime, they will have to be content with the tantalizing images
beamed back to Earth last week.
|
| 456.112 | Volcano-driven atmosphere? | 57897::LEE | Wook... Like 'Book' with a 'W' | Tue Aug 21 1990 21:32 | 6 |
| It wasn't clear to me whether the previous reply stated that eruptions are
currently occuring on Venus. If they are, is it possible that that activity
could be driving the greenhouse effect as well as injecting heat of its own
into the already intensely hot atmosphere?
Wook
|
| 456.113 | | 4347::GRIFFIN | Dave Griffin | Tue Aug 21 1990 22:18 | 10 |
| I'm fairly certain they don't know yet. These were test images only - the
real science work won't start until September at the earliest.
Detection of active volcanos with the radar might require multiple passes to
detect significant shifts in the ground contours. On the other hand, the
amount of information that these guys (and gals) can glean from satellite
images always ends up 10x more than I would think possible...
- dave
|
| 456.114 | | 3625::BIRO | | Wed Aug 22 1990 11:28 | 6 |
| I heard on the radio this morning that they have lost
radio contact again. There has been a incress in Solar
activity so it could have altered the memory.
john
|
| 456.115 | Magellan loses contact with Earth (UPI) | 4347::GRIFFIN | Dave Griffin | Wed Aug 22 1990 15:32 | 80 |
| From: clarinews@clarinet.com
Newsgroups: clari.tw.space,clari.news.urgent
Date: 22 Aug 90 08:55:29 GMT
PASADENA, Calif. (UPI) - Alarmed engineers scrambled Wednesday to
re-establish communications with the errant Magellan Venus radar probe
after the spacecraft suddenly lost contact with Earth for the second
time in a week, officials said.
JPL spokesman Jim Doyle said scientists had no indications of any
new problems when radio contact with Magellan, the centerpiece of a $551
million mission to map the hidden surface of Venus, was suddenly lost
Tuesday night.
``They lost communication at 7:03 p.m. (PDT) last night,'' Doyle
said. ``They were tracking out of Canberra (Australia). They have no
idea why. They have no idea what has gone wrong.''
Last Thursday, a computer glitch, possibly caused by a passing
cosmic ray, temporarily threw the spacecraft into an electronic state of
hibernation that knocked the probe out of contact until Friday when
engineers were able to order Magellan to lock onto distant Earth, 245
million miles away.
The probe was still in a protective ``safe mode'' when contact was
suddenly lost Tuesday. Doyle said data from the spacecraft was normal up
to that point, ``then it went out. They don't know why.''
If Magellan simply went back into hibernation, it presumably would
follow a computer program calling for it to rotate about its long axis
to sweep the sky with its radio antenna. In so doing, the spacecraft's
radio beam would sweep across Earth every few hours, allowing contact to
be re-established.
That did not happen, however, and engineers began radioing commands
to Venus around 1 a.m. PDT, ordering Magellan to begin searching for
Earth.
``If the command reaches the spacecraft, it could respond as early
as 3:30 a.m.,'' Doyle said, adding it could take even longer.
If communications cannot be restored, NASA would be faced with
another major setback in the wake of problems earlier this summer with
the Hubble Space Telescope, trouble with the shuttle program and concern
about the feasibility of the agency's planned space station.
The mishap occurred a few hours after the first radar images of
Venus were released, pictures that were taken last week before Magellan
was knocked out of contact the first time around, possibly by a
high-energy cosmic ray.
John Slonski, Magellan spacecraft systems engineer, said Tuesday it
was not unusual for cosmic rays to alter the contents of a spacecraft's
computer memory and that scientists predicted before launch that one
such ``event'' per year could be expected on average.
But he said it was too early to say exactly what threw Magellan,
launched 15 months ago from the shuttle Atlantis, into hibernation last
Thursday. There was no immediate word on what might have caused the
latest problem.
Magellan was designed to ``see'' through the clouds that
perpetually blanket Venus by bouncing radar beams off the planet's
surface. Extensive computer processing on Earth can convert such radar
data into photo-like images showing surface features as small as a
football field.
Project manager Tony Spear said Tuesday he hoped to begin
around-the-clock radar mapping operations around Sept. 1 to kick off
Magellan's 243-day mapping mission. What impact the latest problem might
have on those plans was not immediately known.
Preliminary radar pictures made just before Magellan went into
hibernation last week revealed a tortured, alien landscape wracked by
volcanos, lava-filled valleys and giant fault systems indicative of
powerful ``venusquakes.''
While scientists were elated with Magellan's initial results, JPL
engineers continued sifting through computer data from the spacecraft to
determine the cause of its trouble last week.
At least three problems, including the loss of a computer's
electronic ``heartbeat,'' derailed Magellan's three-week test program
almost as soon as it got started. But engineers regained contact with
the spacecraft last Friday.
``Diagnosis (of computer data) has shown us exactly what
happened,'' Slonski said of last week's problem. ``But it has not yet
shed any light on the cause of the initial heartbeat loss. We hope
eventually to find out a cause.
``However, it's possible the cause was a transient event ...
perhaps caused by a cosmic ray. This kind of event has happened several
times on other spacecraft and was not totally unexpected on our
spacecraft.''
But Spear said he could not rule out the possibility of a
mechanical problem on board the spacecraft, adding that more data was
needed to pin down the exact cause.
|
| 456.116 | | STAR::HUGHES | You knew the job was dangerous when you took it Fred. | Wed Aug 22 1990 15:32 | 6 |
| There was speculation at the press conference yesterday (Aug 21) that
increased solar activity may have played a role in the spacecraft
anomalies. They mentioned that it would be about a week before they had
solar data to look for a correlation.
gary
|
| 456.117 | Re: Active volcanos | 4347::GRIFFIN | Dave Griffin | Wed Aug 22 1990 15:43 | 42 |
| [Some excerpts from a UPI article on the released pictures. Extraneous
stuff about the mission glitch, etc. has been edited out. -dg]
From: clarinews@clarinet.com
Subject: Scientists reveal Venus pictures
Date: 21 Aug 90 20:12:43 GMT
PASADENA, Calif. (UPI) -- Photo-like test images from the Magellan
probe indicate the hidden surface of Venus is a tortured, alien
landscape wracked by volcanos, lava-filled valleys and giant fault
systems, scientists said Tuesday.
Whether the hellish planet is still geologically active, or whether
its surface is made up of slowly moving continent-size ``plates'' like
those making up Earth's crust, remains to be seen.
``We can't tell from what we've seen if (Venus is) currently active
or even whether the proposed volcanism that we're seeing is very
young,'' said project scientist Stephen Saunders. ``But we're seeing
such a small part of the planet. It'll just take some time for us to
identify the areas that are potentially active.''
He made the comments at a news conference Tuesday highlighted by
the release of a series of black-and-white pictures taken by Magellan's
radar mapping system just before contact was temporarily lost Thursday.
``We (are) seeing volcanic depressions of various kinds, volcanic
lava flows and very highly faulted regions that are called `tessera,'
the Latin word for tile,'' Saunders said in an earlier interview.
``It's a very highly deformed, faulted terrain, very rugged. We've
seen that before at much larger scale, and now with Magellan we're
seeing it all the way down to the scale of a few hundred yards.''
Saunders said the initial images from Magellan appear to show
``volcanic lava flows filling in the valleys. It seems like a big
volcanic swamp (with) molten rock near the surface.''
Earth's surface appears to be made up of giant, slowly moving
continental ``plates'' that make up the planet's crust. The San Andreas
Fault, for example, marks the boundary where the North American plate
plunges under the Pacific Ocean plate.
Saunders said such ``plate tectonics'' appears to work differently
on Venus, a planet with a surface temperature of some 900 degrees and
not a trace of water.
``I think the plates, if there are plates, tend to get broken up a
lot easier,'' he said. ``On Earth, they stay rigid ... and they're only
broken on the edges where they grind together. If there are plates (on
Venus), they're kind of squishy, deformed plates.''
|
| 456.118 | Pumped up between the Sun and Earth? | 21006::CMCCABE | Juvenile Product of the Working Class | Wed Aug 22 1990 15:51 | 12 |
| Re: .112
Pioneer Venus, launched in 1978, returned reports of time-varying
levels of sulfur dioxide in Venus' atmosphere, leading scientists to
infer that there was active volcanic activity taking place. Magellan
will tell (hopefully) how much, and give more information regarding
how this plays in determining atmospheric constituents. It would be
one thing to have a static atmosphere that resulted in a runaway
greenhouse effect, and quite another to have volcanic activity
continuely pumping greenhouse gases into the atmosphere to maintain the
effect. Ah, ain't reality grand? Who woulda thunk... ;^j
|
| 456.119 | | 20408::FISHER | Locutus: Fact or Fraud? | Wed Aug 22 1990 21:52 | 10 |
| A sort-of neat thing:
When Magellan fired its braking rockets to go into orbit around Venus,
Pioneer Venus was commanded to point its UV camera in that direction to try
to photograph the burn. It did not succeed (not bright enough in UV), but
just the fact that PV was still there to even try is really something.
Let's hope Magellan has such a long life :-(
Burns
|
| 456.120 | I've been wondering... | 39635::REITH | Jim Reith DTN 291-0072 - PDM1-1/J9 | Thu Aug 23 1990 11:56 | 13 |
| Since Burns mentioned lifespan...
They heard from magellan briefly yesterday (CNN reported) which seems to
indicate that it is in hunt mode, scanning the skies for Earth. What is this
doing to the mission fuel status? What were/are the margins on the expected
lifetime with all these burns to reorient the craft to Venus, Earth, Guide
stars?? (The mission is 243 days of this, what's actually possible?)
If someone has a brief excerpt about the fuel consumption profile for the
mission and what is spent in this "look for Earth" phase (say per hour) I'd be
interested in a hardcopy or posting.
Thanks
|
| 456.121 | its baaack... | 4581::DENSMORE | Dirty deeds & they're done dirt cheap | Thu Aug 23 1990 11:59 | 5 |
| I heard on the news this morning that contact was re-established. The problem
is apparently "reproducible". Hopefully whatever does the self-correction is
too. :-)
Mike
|
| 456.122 | High-risk fix? | 8713::J_BUTLER | USAR...and ready... | Thu Aug 23 1990 13:15 | 12 |
| CNN reported this morning that contact had been regained and that
a portion of Magellan's memory had been corrupted. NASA's initial
impression was that the memory could be restored, but doing so would
require overwriting a portion of memory involved in the 'safing'
process. As CNN explained it, Magellan's program would have to be
altered and that the alteration would require temporarily disabling
the 'coning' process required to hunt for Earth. This is a high-risk
operation, but it could be done "quickly" to minimize the the chance
of something causing loss of signal before the 'coning' could be
reloaded.
John B.
|
| 456.123 | Write your Congressperson now! | 21002::CMCCABE | Juvenile Product of the Working Class | Thu Aug 23 1990 13:43 | 19 |
| Re: .120
The fuel margin HAS to be large, since it has been mentioned somewhere
previously that 100% of Venus could be mapped if the Magellan mission
were extended to three Venusian years - something Congress/NASA hasn't
yet seen fit to commit to (remember, David Stockman, director of OMB in
the Reagan administration, ALMOST got support for Pioneer 10 and 11 and
Voyager 1 and 2 killed after Saturn encounters - imagine, Digital
couldn't have helped out with Neptune imaging last summer, including
all of the attendant publicity we churned out from that.) Pity Venus
doesn't have a magnetic field to speak of - it could have been used ala
Solar Max for magnetic orientation, obviating the need for excess fuel
(as long as the solar cells hold out - I'm assuming the Sun holding out
is a given ;^) Of course, given Magellan's orbit, a magnetic field
could also create problems akin to what Hubble experiences everytime it
passes through the South Atlantic Anomaly. ANYWAY, cheer up. At least
NASA is flying, Magellan is no Phobos probe, and we're learning
something - the picture in the Globe yesterday was great!
|
| 456.124 | Redundancy? | 39635::REITH | Jim Reith DTN 291-0072 - PDM1-1/J9 | Thu Aug 23 1990 13:43 | 4 |
| Doesn't Magellan have the redundant backup like Voyager(s) that would allow them
to reset one while running from the other? I thought one of the reports about
the first occurance mentioned that the third fallback was to a ROM based system
(Which I would think would be stable while they reloaded RAM)??
|
| 456.125 | Magellan's fuel reserves | 15372::LEPAGE | Caught between Iraq & a hard place | Thu Aug 23 1990 14:41 | 21 |
| Re:.120
Magellan "currently" (i.e. before these multiple safing events) had
enough fuel reserves to last TEN years. Its launch date was the one day
that minimized the delta-V needed to attain orbit. Its trajectory to
Venus was accurate enough so that smaller than expected course
corrections were required. Lastly, the solid braking rocket burn put
Magellan into a perfect mapping orbit so that a trim burn was not
required. All in all, Magellan used less fuel than expected on the way
to and into orbit of Venus leaving its ample reserves larger still. In
fact, there are now plans being formulated for an extended mission that
will involve the equivalent of about a dozen planet wide mapping
sequences (assuming Magellan's present problems are solved).
The latest two incidences where Magellan went into its safe mode
should NOT seriously cut into the fuel reserves. Magellan only needs a
fraction of a gram of fuel to start searching for Earth and only a
fraction of a gram to stop. No fuel is used in between; Magellan just
slowly rolls without any friction and weightless in orbit.
Drew
|
| 456.126 | | STAR::HUGHES | You knew the job was dangerous when you took it Fred. | Thu Aug 23 1990 15:32 | 4 |
| In addition, they plan to move it to a lower orbit after about 4 years
(i.e. after three years of mapping). It has a large propellant reserve.
gary
|
| 456.127 | Latest news on Magellan | 15372::LEPAGE | Caught between Iraq & a hard place | Thu Aug 23 1990 15:38 | 65 |
| Associated Press Thu 23-AUG-1990 01:54 Magellan-Venus
Spacecraft Sends Data to Help NASA Solve Problem
By LEE SIEGEL
AP Science Writer
PASADENA, Calif. (AP) - The Venus-orbiting Magellan spacecraft,
back in radio contact with Earth after twice cutting off
communication, sent flight data home today to help engineers figure
out what went wrong.
``It's sitting there doing nothing but talking to us,'' said
Steve Wall, a Magellan scientist at NASA's Jet Propulsion
Laboratory. ``We're looking for a root cause of the failures.''
NASA engineers restored steady radio contact with Magellan on
Wednesday afternoon after a hair-raising 21 1/2-hour struggle to
prevent the craft from becoming lost in space some 149 million
miles from Earth.
``This is a nervous Nellie, I'll tell you,'' lab spokesman Alan
Wood said.
The successful conclusion of Magellan's latest crisis averted,
at least temporarily, another big setback for NASA. The agency
temporarily grounded its shuttle fleet this summer because of fuel
leaks, and also discovered the $1.5 billion Hubble Space Telescope
had a flawed mirror that produced blurry images.
Wall said he suspected there might be separate causes for
Magellan's latest radio cutoff, which started Tuesday night, and
for the first communications breakdown, which lasted 22 hours
beginning Aug. 16.
But he said, ``We do not believe anything like a massive failure
occurred.''
Wall said that evidence suggests a cosmic ray or high-energy
particle from the sun disrupted Magellan's electronics to cause
last week's problem, while the latest failure raises suspicion of
flaws in the ship's hardware or computer programs.
Ed Sherry, a Magellan official, said programs in the backup
computer appeared to be ``corrupted'' and engineers will rewrite
them to try to solve at least part of the problem.
Magellan's emergency systems also appeared to have
malfunctioned, complicating NASA's efforts to make Magellan call
home, so engineers sent computer commands to the spacecraft to
disable some of the systems.
Just as they did last weekend, engineers also ordered Magellan
to unload its computer memory banks Wednesday night. The process
continued today.
``The patient is resting comfortably and is strong and healthy,
but needs an operation - and we don't know which operation right
now,'' said Tommy Thompson, Magellan science manager.
Wall said the start of Magellan's $744 million mission to make
the most detailed pictures and maps yet of Venus' misshapen
landscape will probably be postponed until the problem is solved.
Scientists had hoped to use Magellan's radar to peer through the
planet's thick clouds during the first week in September.
The spacecraft was launched from the shuttle Atlantis 15 months
ago, then looped around the sun 1 1/2 times, traveling 948 million
miles before it slid into orbit around Venus on Aug. 10.
Long considered Earth's twin gone bad, Venus is similar to Earth
in size, mass and distance from the sun, but it was turned into a
hellish inferno with 900-degree surface temperatures because of an
out-of-control ``greenhouse effect.''
Scientists want to know if the same geological forces that
shaped Earth also sculpted Venus.
Magellan's first test pictures of Venus were released hours
before Tuesday's trouble. They show a landscape broken by quake
faults, giant solidified lava flows, volcanic cinder cones,
collapsed craters and long ridges and valleys.
|
| 456.128 | | 19458::FISHER | Locutus: Fact or Fraud? | Thu Aug 23 1990 16:53 | 13 |
| Gary mentioned the fact that a possible extended mission for Mag. would involve
a closer orbit. AvWeek, in an article written before the recent spate of com
problems, said that one possibility was to use aerobraking to get to a lower
orbit. Interesting! Presumably it would have to be very gentle aerobraking,
since Mag does not have any kind of heat shield (well not the kind to use in
plunging through a planet's atmosphere anyway.) I assume that would still take
a fair number of grams of fuel, though. They would have to first slow it
down slightly at apogee (the Venusian equivalent, anyway...apoven?), which would
lower the perigee so it is in the atmosphere. Drag would then lower the apogee.
After a few orbits, they would need to thrust again to pull the perigee back
out of the atmosphere.
Burns
|
| 456.129 | | 9786::KILGORE | Wild Bill | Thu Aug 23 1990 17:56 | 14 |
|
.101:
>> Capable of showing surface features as small as a football field -- 10
>> times better than ever before -- Magellan, the centerpiece of a $551
>> million project to map Venus's hidden surface, dropped into orbit around
.127:
>> Wall said the start of Magellan's $744 million mission to make
This is turning into quite an expensive little problem...
|
| 456.130 | MAGELLAN Update - August 22 | ADVAX::KLAES | All the Universe, or nothing! | Thu Aug 23 1990 18:40 | 319 |
| Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 08/22/90
Date: 22 Aug 90 17:38:17 GMT
Reply-To: baalke@mars.jpl.nasa.gov (Ron Baalke)
Organization: Jet Propulsion Laboratory, Pasadena, CA.
Magellan Status Report
August 22, 1990
At 3:30 pm (PDT) last night, contoller at the Jet Propulsion Lab
were unable to uplink to the the Magellan spacecraft using the 34
meter antenna in Goldstone, California. Several sweeps were attempted
utilizing different sweep paramters. Some of the sweeps were getting
into the spacecraft several minutes (from six to twelve minutes) after
the uplink would normally cause a mode change. The cause is under
investigation.
At 7:03 pm (PDT) last night while Magellan was in communication
through the Canberra station, contact was lost with the spacecraft.
There were no unusual activities occurring with Magellan at that time
and all spacecraft readings were normal.
Analysis of the signal at the time of loss (signal strength and
spectrum) suggests the spacecraft underwent a change in its pointing
direction. There is no evidence which would be consistent with a
transmitter failure or a loss of power to transmitter functions.
At 1:38 am (PDT) this morning, a series of commands were
transmitted to Magellan through the Madrid station at very high power
levels to reconfigure several onboard data systems and to reset the
safing procedure. An additional set of commands were transmitted at
about 6:30 am. These additional commands reset another computer and
will change attitude control gyroscopes respectively. The last of
these additional commands is to be sent at approximately 9:30 am today.
JPL will report on further communications attempts and any
further analysis of the situation at 10:15 am during a status report
from JPL. It will be on NASA Select TV.
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
Newsgroups: sci.space,sci.astro
Subject: Another Magellan Update - 08/22/90
Date: 22 Aug 90 21:32:33 GMT
Reply-To: baalke@mars.jpl.nasa.gov (Ron Baalke)
Organization: Jet Propulsion Laboratory, Pasadena, CA.
Magellan Update
August 22, 1990
1. At 7:03 PM PDT on Tuesday, August 21, the Deep Space
Network (DSN) reported that the Canberra DSS43 receiver lost
two-way lock on the telemetry signal from Magellan. At
7:06, the receiver reacquired lock in a backup one-way
mode, but the signal strength reported by the Automatic
Gain Control (AGC) levels was dropping from the nominal level.
At 7:06:46 the receiver again lost lock.
By 7:08, the DSN spectrum analyzer monitoring the
Magellan signal window no longer showed the spacecraft
signal. At 7:16:30 the signal was seen again in the spectrum
analyzer for approximately one minute at a low level.
Since that time, no signal has been detected from Magellan.
2. At the time the incident began, the spacecraft was
performing no unusual activities and the telemetry signal
showed normal conditions at the 40 bit per second rate.
The spacecraft was in the same configuration achieved
after recovery from the previous loss of signal incident:
o Both Command Data System (CDS) computers were
operating normally, with CDS-A prime;
o The Attitude Articulation Control Subsystem (AACS)
computer was still executing from Read-Only Memory
(ROM) in memory A, using the Central Processing Unit
(CPU) B and the Input-Output Drive Assembly (IODA) B;
o The spacecraft pointing was stationary with the
Medium Gain Antenna pointed toward Earth, the solar
panels pointed fully toward the Sun, and controlling
its attitude using hydrazine thrusters;
o The spacecraft was in sunlight, moving from apoapsis
(the furthest point from the planet), toward
periapsis and occultation behind Venus.
3. If the spacecraft had resumed the standard ROM antenna
coning rate of one cycle every two hours, the signal
would have been seen again within 4 hours. (By waiting
through 2 cycles of two hours, the possibility of the
first cycle passing Earth while the spacecraft was in
occultation behind Venus could be accepted.)
The recovery of the spacecraft signal from the previous
signal loss incident occurred when the attitude control
computer entered ROM safing and initiated antenna coning.
As part of this initiation, the attitude control computer
purposefully marked both Random Access (RAM) memories as
unusable, so as to force entry into ROM. It is therefore
unlikely that the attitude control computer is executing
in RAM memory.
4. The pattern of signal loss suggests that the incident
involved a real change in the spacecraft pointing
direction. The signal dropped in strength gradually over
a period of approximately 2 minutes. It is not
consistent with a sudden failure of the spacecraft
transmitter, nor with a loss of power to the transmitter
systems. Given the known Medium Gain Antenna pattern,
the rate of signal loss suggests a spacecraft turn rate
of approximately 0.5 degrees per second.
The pattern of signal strength fluctuation suggests that
rather than turning away deliberately, the spacecraft
pointing may have fluctuated through Earth several times.
5. Spacecraft telemetry was received and processed for
analysis by the spacecraft engineers up to 7:02:56 PM
PDT, several seconds after the apparent start of the
incident. Through that period, the telemetry continued
to indicate normal spacecraft operations. The telemetry
was, however, specifically unable to show the detailed
operation of the pointing control systems because of the
continued operation of ROM safing in the AACS.
6. The spacecraft entered this incident with its batteries
fully charged and its systems configured to use minimal
power. In this configuration, even with the solar arrays
incorrectly turned so as to receive no power from the
Sun, the spacecraft could continue operations for between
6 and 10 hours.
7. In order to avoid the risk of exhaustion of the
batteries, the Project decided to transmit commands to
the spacecraft at 1:38 AM PDT on Wednesday, August 22
using the 350 kilowatt high power transmitter at the
Madrid 70 meter antenna station. The commands were chosen to
force the spacecraft to swap the Input-Output Drive Assembly
(IODA) to the A unit and restart ROM safing. This swap
of the IODA and restart of ROM execution is believed to
address the most plausible faults which could have led to
this incident.
There were 4 specific commands, which instructed first
one and then the other CDS computer to switch first one
and then a second relay to cause the IODA swap and ROM
restart. These commands were assembled into a single
Immediate Action Program and transmitted to the
spacecraft in a single string.
Command reception at the spacecraft was expected through
the Low Gain Antenna at 7.81 bits per second. This
antenna has a very wide reception pattern, which together
with the very powerful transmitter provided the best
possible chance for command reception, The set of 3
commands was transmitted 3 times separated by 4 minute
intervals over the period from spacecraft apoapsis (when
the doppler frequency rate of the appropriate receiver
lock frequency is near zero) to the start of occultation
behind Venus.
8. The initial command transmission did not cause
reacquisition of the spacecraft's signal. The Project is
currently evaluating the appropriate commands to transmit
next. The intended command sequence will perform the
following steps:
o Disable CDS Heartbeat Loss response;
o Turn both AACS memories on; and
o Command the AACS to start execution in memory A.
This set of commands is intended to stop or prevent the
spacecraft from operating in the AACS-B memory, which has
been observed to cause faults both at the time of Solid
Rocket Motor case separation (August 10) and during the
first loss of signal incident (August 16).
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
Newsgroups: sci.space,sci.astro
Subject: Magellan's First Images Released
Date: 22 Aug 90 23:48:02 GMT
Reply-To: baalke@mars.jpl.nasa.gov (Ron Baalke)
Organization: Jet Propulsion Laboratory, Pasadena, CA.
Magellan's First Images
August 22, 1990
Yesterday, the Jet Propulsion Lab released the first radar images
of Venus sent back by the Magellan spacecraft. The images reveal a
planet ripped and shredded by powerful stresses that appear far more
pervasive than the tectonic forces that generate great earthquakes and
catastrophic volcanoes on Earth. The synthetic aperature radar aboard
Magellan pierced through the dense clouds on Venus, and recorded a
series of long, narrow images of the planet. Giant faults and past
volcanic activity were seen in the images.
Magellan's first images of Venus show a volcanic highland known
as Beta Regio which features ridges and valley floors where volcanic
flows have hardened with a network of fractures and small craters.
These first radar images show Venus to have a remarkably violent
landscape shaped by impact craters, quake faults with vast lava flows,
and ridges and valleys akin to those in the Western U.S. The new radar
imagery of Venus is ten times as detailed as any previously obtained
data. The spacecraft's radar system will continually san a narrow
band on the planet's surface, about 12 miles wide. The images
released yesterday covered several short stretches, ranging from 50 to
90 miles long, captured during 1 1/2 orbits of Venus.
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
Newsgroups: sci.space,sci.astro
Subject: Magellan is back!
Date: 22 Aug 90 22:25:00 GMT
Reply-To: baalke@mars.jpl.nasa.gov (Ron Baalke)
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
August 22, 1990
2:40 p.m. PDT
Flight controllers at the Jet Propulsion Laboratory reported
Wednesday afternoon they have reacquired the Magellan spacecraft after
losing its signal late Tuesday.
The spacecraft's carrier signal was heard shortly after noon PDT,
but only briefly before the spacecraft went behind the planet Venus.
When it emerged again from the planet, the signal was heard again but
briefly. This indicated the spacecraft was in a safing mode in which
it was coning -- moving in a circular motion searching for Earth. In
that mode the transmitter signal would be expected to cross Earth
about every two hours.
Shortly after 2 p.m. PDT the signal was heard again and
controllers were able to get a lock on the spacecraft. That signal
lasted for about 25 minutes or more during which time engineering
telemetry was received. It was a clear indication the spacecraft is
coning; its solar arrays are pointed toward the sun and it is receiving
power, and Magellan engineers are confident they will reacquire the
signal shortly after 4 p.m. PDT and will receive more data.
The data received on the last pass indicated the spacecraft's
subsystems are healthy.
A project spokesman said flight controllers are cautiously
planning the next commands they will send to Magellan.
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
Newsgroups: sci.space,sci.astro
Subject: Yet Another Magellan Update - 08/22/90
Date: 23 Aug 90 00:49:18 GMT
Reply-To: baalke@mars.jpl.nasa.gov (Ron Baalke)
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
August 22, 1990
4:50 p.m. PDT
Flight controllers at the Jet Propulsion Laboratory reported the
Magellan spacecraft had confirmed at 4:33 p.m. PDT it had responded to
a computer command and had established constant contact with Earth. In
the current configuration, Magellan will keep its medium-gain antenna
aimed at Earth and engineers will continue to receive engineering data.
Two other commands were then sent to the spacecraft to prevent
its further entry into coning by disabling two paths it has taken to
enter fault protection, or safing modes.
Magellan lost communication with Earth late Tuesday. Its carrier
signal was heard shortly after noon Friday PDT, but only briefly
before the spacecraft went behind the planet Venus. When it emerged
again from the planet, the signal was heard again but briefly. This
indicated the spacecraft was in a safing mode in which it was coning
-- moving in a circular motion searching for Earth. In that mode the
transmitter signal would be expected to cross Earth about every two hours.
Shortly after 2 p.m. PDT the signal was heard again and
controllers were able to get a lock on the spacecraft. That signal
lasted for about 25 minutes during which time engineering telemetry
was received. It was a clear indication the spacecraft was coning; its
solar arrays were pointed toward the sun and it was receiving power.
Controllers sent commands at 3:51 p.m. PDT to the spacecraft
ordering it to stop coning and maintain direct communication with Earth.
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
|
| 456.131 | MAGELLAN Update - August 23 | ADVAX::KLAES | All the Universe, or nothing! | Fri Aug 24 1990 16:01 | 79 |
| Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 08/23/90
Date: 23 Aug 90 19:35:36 GMT
Reply-To: baalke@mars.jpl.nasa.gov (Ron Baalke)
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
August 23, 1990
12 noon PDT
Flight controllers at the Jet Propulsion Laboratory said the
signal from the Magellan spacecraft at Venus was re-acquired by the
Deep Space Network station at Goldstone, Calif., at 12:03 p.m. PDT on
August 22, following loss of signal the previous evening.
Subsequent acquisitions of the signal at 2:08 p.m. and 4:12 p.m.
showed the spacecraft was in good health and that it was coning --
looking for Earth. The spacecraft's batteries are charged, solar
panels are pointed toward the sun and all subsystems appear to be
working.
Commands were sent during the 4:12 p.m. acquisition to stop
coning and stable communications were established.
Telemetry indicates that Magellan received the majority of all
the commands that had been sent to it "in the blind," that is, during
the time period when the signal was lost. The fault record in the
spacecraft's memory showed that it had automatically performed nine
switches between various combinations of primary and backup computers.
Just over two kilograms of fuel were consumed during the period the
spacecraft was coning.
During the night additional commands were sent to perform memory
readouts from both the main and attitude control computers. More
readouts are scheduled to be sent today. Also, onboard fault protection
is being re-established and other diagnostic commands are being sent.
The focus for the flight team is now to establish a safe and
protected spacecraft, and to collect evidence from the spacecraft's
computer memories as to the actions it took automatically during the
loss of signal period. When the evidence is in, the team can begin to
reconstruct the cause of the initial failure.
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
Newsgroups: sci.space,sci.astro
Subject: Magellan News Conference (Forwarded)
Date: 23 Aug 90 19:37:09 GMT
Reply-To: baalke@mars.jpl.nasa.gov (Ron Baalke)
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN NEWS CONFERENCE SET FOR FRIDAY, AUGUST 24
A news conference is scheduled at the NASA Jet Propulsion
Laboratory, Pasadena, Calif., at 2 p.m. EDT, Friday, August 24 to
discuss recent problems with the Magellan spacecraft and to release
more images of Venus acquired during the first two radar test orbits.
A videotape also will be released.
Participants include Project Manager Anthony Spear; John Slonski,
JPL Spacecraft Systems Engineer; Frank McKinney, Magellan Program
Manager, Martin Marietta Corp. and Dr. Steve Saunders, Project
Scientist.
The conference will be carried live on NASA Select television,
Satcom F2R, Transponder 13, C-band, at 72 degrees West Longitude, with
2-way question and answer capability.
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
|
| 456.132 | | 28751::TOWSLEE_G | Toecutter | Fri Aug 24 1990 17:09 | 17 |
|
Re: .125
> The latest two incidences where Magellan went into its safe mode
> should NOT seriously cut into the fuel reserves. Magellan only needs a
> fraction of a gram of fuel to start searching for Earth and only a
> fraction of a gram to stop.
Re: .131
> Just over two kilograms of fuel were consumed during the period the
> spacecraft was coning.
Which is correct?
|
| 456.133 | Coning is different than a linear roll | 39635::REITH | Jim Reith DTN 291-0072 - PDM1-1/J9 | Fri Aug 24 1990 18:25 | 7 |
| I didn't think the estimate was right but I didn't comment. My reason for asking
originally was because I had heard that it was a coning pattern which would
require constant thrusting (I assume that it can't gimbal on it's gyros to cone)
I guess I should ask it differently now that we have a coning figure. How much
fuel is on board?
|
| 456.134 | Orbital terminology | 42653::HAZEL | Every couple has its moment in a field | Sat Aug 25 1990 10:18 | 10 |
| Re. .128
>...apogee (the Venusian equivalent, anyway...apoven?)
The generic term is "apoapsis". Closest approach is "periapsis".
The terms perigee and apogee are specific to Earth orbit. Likewise,
perihelion and aphelion are specific to solar orbit.
Dave Hazel
|
| 456.135 | | STAR::DZIEDZIC | | Mon Aug 27 1990 11:36 | 4 |
| I believe the figure I heard on the news was that there are some
150 pounds of fuel remaining. (Maybe that was kilograms - wasn't
paying real close attention. I know the coning used up about 5
pounds of fuel.)
|
| 456.136 | MAGELLAN Update - August 24 | ADVAX::KLAES | All the Universe, or nothing! | Mon Aug 27 1990 14:55 | 125 |
| Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 08/24/90
Date: 24 Aug 90 21:14:06 GMT
Reply-To: baalke@mars.jpl.nasa.gov (Ron Baalke)
Organization: Jet Propulsion Laboratory, Pasadena, CA.
Magellan Status Report
August 24, 1990
During Thursday, August 23, the Magellan spacecraft remained in
secure communications contact. There was no indication of any further
anomalous behavior.
The following commands were transmitted to the spacecraft on
August 23: (all times are PDT)
o 06:20 - The star scanner was turned off on both the
A and B sides in order to eliminate the possibility
that asynchronous interrupts from it were responsible
for the Loss of Signal problems.
o 08:05 - The ROM Overlay buffer in the Attitude and
Articulation Control Subsystem B (AACS-B) memory was
reloaded to correct the memory corruption problem
caused during the first Loss of Signal incident.
o 11:04 to 15:30 - A number of miscellaneous Command Data
Subsystem (CDS) safing flags and fault protection counters
were reset.
o 18:05 - The CDS Heartbeat Loss Response was re-
enabled, with the pointer for the Response command
table set at 7.
o 20:50 to present - Memory readouts of the AACS-A and B
memories were continued.
Commands are planned for today to:
o 5:12 - Turn off the Two-Way Non-Coherent (TWNC)
mode in the spacecraft telemetry system in order to
obtain coherent tracking to establish a new orbit
solution and Deep Space Network (DSN) tracking predictions.
As part of the same command transmission, the CDS Command
Loss Timer will be reduced from 96 to 12 hours.
o Change temporarily from 40 to 1200 bits per second
through the Medium Gain Antenna to accelerate (if
possible) the completion of memory readouts.
No good timeline is available yet of the sequence of events
during the second Loss of Signal incident. There is also no agreed
prime cause of either Loss of Signal incident, nor of the subsequent
configurations during each incident.
Despite this uncertainty, all elements of the Project and
external experts at both JPL and Martin Marietta agreed that it was
preferrable to re-enable the autonsequences of a failure of the AACS
computer with the Heartbeat Loss disabled. The command table pointer
was positioned to obtain the desired AACS configuration cthe table
were performed.
At 11:00 AM PDT a Press Conference will be conducted at JPL to
discuss theadditional images of Venus acquired during the first one
and on half orbits of the first Radar Test. John Slonski from JPL
will describe the incident with support from Frank McKinney from
Martin, while Dr. Stephen Saunders (JPL) and Dr. Keith Raney (Canada
Center for Remote Sensing) will discuss the radar test results and the
on-going scientific analysis.
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
Newsgroups: sci.space,sci.astro
Subject: Magellan Update #2 - 08/24/90
Date: 24 Aug 90 21:55:42 GMT
Reply-To: baalke@mars.jpl.nasa.gov (Ron Baalke)
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
August 24, 1990
2:30 p.m. PDT
The Magellan spacecraft is stable and communicating with flight
controllers on Earth with no indication of further anomalies. But
project engineers said today since the loss of signal is not well
understood, it is assumed it can happen again. Emphasis, therefore, is
being placed on refining contingency plans to quickly detect and take
action in the event of a repeat of the problem.
Commands today changed the telemetry temporarily from 40 bits per
second through the medium-gain antenna to 1,200 bps to accelerate the
completion of memory readouts.
Additionally, a timeline was developed to outline steps to start
of radar operations and commands were transmitted to Magellan to
perform the functions designed Thursday. They include:
Turning off the star scanner on both the A and B sides in order
to eliminate the possibility that asynchronous interrupts from it were
responsible for the loss of signal problems; steps were taken to
correct the memory corruption problem caused during the first loss of
signal incident, and a number of miscellaneous command data system
safing flags and fault protection counters were reset.
Members of the project and external experts at both JPL and
Martin Marietta are analyzing the available data in an effort to
determine the cause of the signal loss problems. Among the causes
considered was the remote possibility that the solid rocket motor
shell did not separate completely as scheduled. Project spokesmen
said, however, only one spike was seen in data and only for a few
seconds after separation, and there is currently no doubt the
separation was complete.
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
|
| 456.137 | Magellan's fuel use | 15372::LEPAGE | Caught between Iraq & a hard place | Mon Aug 27 1990 15:44 | 12 |
| Re:.132
Magellan would NORMALLY use only a few grams of fuel to search for
the Earth to regain contact. However for some as yet unexplained reason
Magellans thrusters are firing VERY frequently using up much more fuel.
The latest estimate that I heard (which was after my reply .125)
indicated that about 5 pounds of fuel was used during the last
communication blackout. About 251 pounds of fuel remain. At the
normal rate of consumption, that 5 pounds of fuel amounts to something
like three months of fuel (out of enough to last about 120 months).
Drew
|
| 456.138 | Hey, get out of my radio path, will ya! | 6056::GAUDET | Nothing unreal exists | Mon Aug 27 1990 18:15 | 11 |
| What about the possibility that something (besides Venus) simply "got in the
way" of Magellan's radio signal? I know it may be a bit far-fetched, but given
that there's 140+ million miles between Earth and Magellan, and we only plan for
radio blackouts when the probe is behind Venus, who's to say that something else
didn't just get in the way (a large asteroid on just the right trajectory at
just the right distance?) and cause the spacecraft to start coning? Maybe
there's a Venusian moon we don't know about? :-)
OK, enough speculation...it's been a tough day. :-)
...Roger...
|
| 456.139 | | 3168::BIRO | | Mon Aug 27 1990 19:15 | 8 |
| I dont think something is getting in its way, unless it gets
in the way of the star sensor also. The memory dump shows
a swinging back and forth to find earth. The one possible
object could be the spent booster. The first problem started
when it was jetterson, the backup gyro 'failed'...
jb
|
| 456.140 | Bloody Hackers.... | 7192::SCHWARTZ | Nuke Gringrich Now! | Mon Aug 27 1990 21:29 | 5 |
| Mebbe its those damn Venerian kid hackers that are linking in and
messing with the software. Betcha there's not a lot of security for the
on-board system :-)
-**Ted**-
|
| 456.141 | MAGELLAN Update - August 27 | ADVAX::KLAES | All the Universe, or nothing! | Tue Aug 28 1990 14:32 | 43 |
| Date: 28 Aug 90 03:24:14 GMT
From: (Ron Baalke)
Subject: Magellan Update - 08/27/90
MAGELLAN STATUS REPORT
August 27, 1990
The Magellan spacecraft is in a stable operations state today in
ROM safing. Downlink telemetry on the medium-gain antenna is at 40
bits per second and uplink is at 7 bps.
The spacecraft is using its A side command data system (CDS) and
attitude and articulation control subsystem (AACS).
Spacecraft team members are being moved from the Martin Marietta
Corp. offices in Denver to JPL to join a spacecraft anomaly
investigation group.
The Magellan Project office has listed several potential causes
of the loss of signal problems experienced on Aug. 16 and again on
Aug. 21.
They include: AACS memory B failure at separation of the solid
rocket motor; shock from the explosive bolts; electrical transients
due to arcing or static electricity discharges.
Both signal loss incidents involved AACS computer runaway with
memory corruption. The possible causes for that problem listed by
project are: First entry into RAM safing caused by bit corruption due
to single-event upset such as a cosmic particle hit, or a hung bit and
problem with AACS B-side on-board computer; particle hits at Venus;
electrical transients due to arcing or static electricity discharges.
In meetings today, project officials were to determine when radar
mapping would be resumed, with indications it may be about Sept. 19.
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
|
| 456.142 | | STAR::HUGHES | You knew the job was dangerous when you took it Fred. | Tue Aug 28 1990 15:46 | 9 |
| The static discharge idea is interesting. A number of comsats in
geostationary orbit experienced various failures that were eventually
traced back to static buildup and subsequent discharge.
Magellan's orbit is unlike that of any previous Venus orbiters so it is
possible that it could encounter such an effect and previous missions
would not.
gary
|
| 456.143 | Solar maximum compatibility? | 42653::HAZEL | Every couple has its moment in a field | Tue Aug 28 1990 16:37 | 7 |
| Does anyone know whether Magellan was designed to be operational during
a solar maximum cycle? Although it must have been designed for
operation at Venus' orbit, I wonder if it was intended to be
operational while the Sun was as active as it is at the moment?
Dave Hazel
|
| 456.144 | MAGELLAN Update - August 28 | ADVAX::KLAES | All the Universe, or nothing! | Wed Aug 29 1990 15:38 | 81 |
| From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 08/28/90
Date: 28 Aug 90 18:53:24 GMT
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
August 28, 1990
The Magellan spacecraft continues to operate in a stable safing
state today.
The spacecraft Anomaly Investigation Team led by Frank McKinney
of Martin Marietta has convened at JPL and is looking into the loss of
signal events.
Commands were transmitted to the spacecraft August 27 to prevent
ROM safing information from being "zeroed out" in the process of
switching Attitude and Articulation Command Subsystem components.
In addition to the all-out efforts by each tracking complex to
recover the signal during and after the second signal-loss event, many
important operations during recovery were made possible by special
efforts on the part of the Deep Space Network (DSN).
They included updated tracking predictions to account for any
orbit changes caused by the use of hydrazine. Also telemetry was
switched from 40 to 1200 bits per second over the Goldstone DSN
70-meter station to perform memory readouts -- twice each of the AACS
A and B memories.
In addition to the DSN, the Magellan Project noted its gratitude
to the Pioneer Venus Orbiter project for turning its S-band transmitter
on continuously, at cost to its science data collection, in order to
provide a beacon signal to assist in reacting quickly to another
possible loss of spacecraft signal.
Current plans call for a return to normal attitude control
operations on Sept. 4, resume star calibrations two days later, return
to the high-gain antenna on Sept. 12, begin radar testing on Sept. 14
and radar operations on Sept. 15.
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
From: pjs@aristotle.JPL.NASA.gov (Peter Scott)
Newsgroups: sci.space
Subject: Re: Magellan fuel capacity
Date: 28 Aug 90 16:51:37 GMT
Organization: Jet Propulsion Laboratory, NASA/Caltech
In article <2849@inews.intel.com>, pmeyer@cmdnfs.intel.com (Paul
Meyer) writes:
>Followup-To: pmeyer@cmdnfs.intel.com
^^^^^^^^^^^^^^^^^^^^^^^
Is that really what you intended?
> I've seen several comments on the amount of fuel Magellan
> consumed during it's communications losses and it's coning to regain
> contact, but the numbers don't mean anything to me. How significant is
> this fuel loss? How will it affect Magellan's mission? How much fuel
> does Magellan now carry?
The fuel loss is insignificant. Magellan was originally planned
to carry 10 years' worth of fuel on arrival at Venus; however, they
discovered when they got there that it would actually last much much
longer; they had been using fuel to counteract the torque caused by
light pressure on the solar panels, but when the SRM was jettisoned
the new mass distribution put the center of mass right between the
solar panels, so they don't have to burn nearly as much fuel to
counteract torque. They now have enough fuel for 100 years of ops.
--
This is news. This is your | Peter Scott, NASA/JPL/Caltech
brain on news. Any questions? | (pjs@aristotle.jpl.nasa.gov)
|
| 456.145 | MAGELLAN Update - August 29 | ADVAX::KLAES | All the Universe, or nothing! | Thu Aug 30 1990 13:42 | 49 |
| Date: 29 Aug 90 20:08:47 GMT
From: (Ron Baalke)
Subject: Magellan Update - 08/29/90
MAGELLAN STATUS REPORT
August 29, 1990
The Magellan spacecraft remains stable today in a ROM safing
mode. Preparations are being made, including simulation verification
laboratory testing of commands, to move attitude control from ROM
safing to the standard attitude control processing with RAM memory on
September 4. That change is expected to provide a safer spacecraft
operations state, backed by RAM and ROM safing, and insight into
attitude control operations via telemetry.
A meeting was held yesterday afternoon on the Command Data System
(CDS) "Heartbeat Table" changes -- that is, changes in the scheduled
commands which control the constant checking system between the CDS
and the Attitude and Articulation Control Subsystem (AACS). A
consensus was reached by the spacecraft investigation and the fault
protection technical groups on a table modification which favors the
A-side AACS components over the B-side. That change was to be reviewed
today.
In the future, RAM safing will be modified to exclude guide star
coning for an attitude knowledge update to point the medium- gain
antenna, which involves a long delay before coning actually starts in
that mode. Instead RAM coning of the medium-gain antenna will start
immediately after a signal loss, as is the case now with ROM coning.
Here is the latest recovery plan with key milestones:
o Go to standard attitude control on September 4.
o Switch from thrusters to reaction wheels on September 5.
o Switch uplink from low-gain to medium-gain on September 6.
o Begin practice of star scans on September 8.
o Begin sequence with star scans on September 10.
o Switch downlink and uplink to the high-gain antenna and
playback stored data on September 12.
o Radar test on September 14.
o Start radar operations September 15.
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
|
| 456.146 | MAGELLAN Updates - August 31 and September 1 | ADVAX::KLAES | All the Universe, or nothing! | Tue Sep 04 1990 15:37 | 441 |
| From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 08/31/90
Date: 1 Sep 90 18:30:43 GMT
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
August 31, 1990
The Magellan spacecraft remains stable in a ROM safing mode
today. The project reports it remains on schedule for transition to
RAM attitude control for Saturday, Sept. 1. The command load will be
sent at 5 a.m. PDT on September 1 and transition to RAM control is
expected by 10 a.m.
The spacecraft will stay on attitude and articulation control
subsystem (AACS) computer A and Memory A. The B-side systems will be
used only in the event of a loss of heartbeat -- the continuous
communication between the spacecraft's command data computer and the
attitude and articulation control computer.
RAM attitude control will continue without star calibrations
until September 6 when star searches will be initiated again. It is
expected that attitude drift, which star calibrations control, will be
slow and not sufficient to hamper communications with the medium-gain
antenna.
The source of the two losses of signal have not been found , and
there is not yet a model which links the Memory B failure to later
runaway computer operations which brought on the signal loss events.
A working group has been formed to begin Memory B reprogramming
planning. They will first identify long and short term options and the
associated reprogramming needed for both memories. A command and data
system software modification is being pursued to permit monitoring of
Memory B while it is flagged as non-usable.
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Anomaly Review - 08/31/90
Date: 4 Sep 90 02:09:06 GMT
Organization: Jet Propulsion Laboratory, Pasadena, CA.
Magellan Anomaly Review
August 31, 1990
1. The Magellan Project conducted a special review at JPL on
Wednesday, August 29, of its analysis of the various anomalies
since arrival in Venus orbit. The review specifically
addressed the two Loss of Signal incidents and plans for
return to normal operations and the start of radar mapping.
The review was led by John Casani and included experts from
JPL, Martin Marietta, and Hughes Aircraft, as well as both
present and previous members of the Project. The Galileo Project,
which shares many of the software and hardware elements used on
Magellan, was well represented. Martin at Denver was able to listen
to the proceedings, as did the SSED at NASA Headquarters.
2. The review was led by Frank McKinney, Magellan program manager at
Martin, who is currently directing the diagnosis and recovery
Tiger Team under Jim Scott, the JPL Magellan Mission Director.
3. The anomalies covered included:
o Attitude and Articulation Control Subsystem-B (AACS-B) memory
address fault shortly after Solid Rocket Motor (SRM) case
separation;
o First Loss of Signal incident during the planned star
scan maneuver during the second orbit of the Radar Test;
o Second Loss of Signal incident during quiescent operation
in AACS ROM safing.
The listing of these anomalies together does not imply a
judgement as to whether they are logically related, although
the second and third probably are.
4. AACS-B Memory Address Problem
o The problem first appeared at 7 2/3 seconds after
detonation of the explosive bolts to separate the Solid
Rocket motor case. This time is known within -2/3 +0
seconds from reliable telemetry.
o The problem was seen as the sudden appearance of 4
commands in the AACS-B memory command buffer at a time
when no commands were sent from the Command Data Subsystem-B
(CDS-B). These commands were rejected by the AACS-A CPU as
not valid commands.
o Subsequently, invalid commands were rejected for at least
24 hours. The next two star scan maneuvers, which
involved identical commands from the CDS, each produced
8 command rejections. The third star scan, 36 hours
after the fault appeared, produced no command rejections.
The fault is therefore either intermittent or cured itself.
o Analysis of partial readouts of AACS-B memory shows that
the fault was in the memory address hardware, and caused
bit 4 (lsb 01234...msb) to stick high (logical 1). As a
result, attempts to either read or write addresses with
bit 4 low accessed the wrong word in memory. The fault
started at address 6000 and continued at least through
address 6707. It did not produce failure of the write-
protected memory, which is checksummed, nor did it cause
loss of heartbeat.
o The fault did not cause any incorrect spacecraft
behavior, since at the time AACS-B memory was operating
only as backup to memory A. However, to avoid any risk
of incorrect commands being mistakenly accepted for
execution, a flag was set in AACS-A memory instructing
the AACS CPU that memory B was powered off. After this
point, no further AACS reads or writes were performed to
memory B except for the heartbeat word. Therefore, AACS-
B memory was not kept updated in parallel with memory A.
At the time of the subsequent first Loss of Signal
incident, the Project was about to perform two actions:
- Change Power On Reset to leave the offline memory
power-off flag set; and
- Alter the Checksum word in AACS-B memory to prevent
execution from RAM in memory B.
o Subsequent analysis has identified various possible
mechanisms for the address fault, including:
- Shock/temperature stress induced open circuits;
- Shock/temperature dependent short circuits;
- Component failure within either the address line
buffer or one of the 32 TCC-244 memory chips
connected to the affected line.
o Earlier attempts to reproduce the observed behavior
through open circuits on multiple ground units failed to
give the observed pattern. However, JPL now believes
that the combination of an open circuit and a high gate
leakage current from a TCC-244 unit could give the
observed pattern.
5. First Loss of Signal
o The Loss of Signal was caused by detection by both CDS
computers of loss of the Heartbeat signal from both AACS
memories for a period of more than 6 seconds during the
star scan maneuver of the second Radar Test orbit. CDS-A
therefore issued instructions to reconfigure the AACS
from the A memory, CPU, and IODA units all to the B
units. This change in configuration initiated a Power On
Reset and started execution of RAM safing in the B units.
The Heartbeat loss detection was recorded in CDS memory
as occurring at 3:33:43 spacecraft time.
o At this phase in the star scan maneuver, the scan of both
stars had been successfully completed, and a good
attitude update had been accomplished with no activations
of either the foreground or background star scanner
filters. The second star window closed at 3:33:34, at
which time interrupts from the star scanner were masked
out. Note that these times imply a nine second total
time gap. Since Heartbeat Loss is not detected and
recorded in telemetry until 6 seconds after it is last
seen, this suggests approximately a 3 second gap after
the second star window closing before the incident began.
o At this time, there is no concurrence on the cause of the
loss of AACS heartbeat. The lack of star scanner filter
action strongly suggests that the spacecraft was not
being subjected to any unusual high energy particle
events. Although Pioneer Venus has reported two Single
Event Upsets during the days before and after the
Magellan incident, this is not an unusual rate for PVO.
The Project is currently exploring multiple hardware and
software possible causes.
o It is unlikely that the AACS-B memory address problem
could have been responsible for the initial Heartbeat
Loss, since it was:
- Not being used by AACS-A CPU; and
- Was correctly transmitting Heartbeat to CDS-B.
o After eventual recovery of the spacecraft signal, it has
been possible to reconstruct a very good schedule of what
happened during the first incident from Delayed
Engineering Data and Fault Protection tables in the CDS
and AACS memories. This process was particularly
successful because the spacecraft was collecting the DED
during the star scan since it was out of contact with
Earth, and continued to do so for roughly one hour after
the start of the incident. In addition, the tape
recorder was collecting the full engineering telemetry
during the star scan, and continued to run for several
seconds after the start of the incident. This recorded
data may prove particularly useful in identifying the
initial cause of the incident after the spacecraft can
return to High Gain Antenna and replay both the
engineering data and the second half of the second Radar
Test recorded instrument data.
o Two subsequent events during the first incident are known
to have occurred, but their cause is unknown:
- After 6 hours 55 minutes in RAM safing, the AACS-B
CPU exited RAM safing and entered RAM attitude hold
mode; and
- After an additional 6 hours 16 minutes, the AACS-B
CPU started to execute random addresses in both the
A and B memories and eventually hit a Trap instruction.
It is not clear whether the previously observed AACS-B
memory address problem could have caused either of these
events.
o The sequence of events after the Trap instruction are
well understood, and led to the recovery of the
spacecraft signal through the execution of the second row
in the Heartbeat Loss Response table. The spacecraft was
recovered operating in ROM safing using AACS CPU-B, IODA-
B, and memory A. It remained in this state until the
start of the second Loss of Signal incident.
6. Second Loss of Signal
o The second loss of signal occurred while the spacecraft
was quiescent in ROM safing. Reconstruction of a precise
sequence of events for the second incident has been much
more difficult, since the spacecraft was not deliberately
recording Delayed Engineering Data, and so many events
took place that the fault protection buffers were overwritten.
o It is known that the CDS executed row 2 of the Heartbeat
Loss Response table at 1:49:16 spacecraft time, at the
same time as loss of downlink telemetry. This should
have caused eventual re-entry into ROM safing execution
and signal recovery through a restart of Earth coning.
o Unfortunately, it is clear that multiple additional
entries into Heartbeat Loss occurred due to either
failure to start of subsequent reoccurrence of failure of
Heartbeat. In total, 9 further passes were made through
the Heartbeat Loss Response table during the second incident.
o Two of these passes are thought to be due to ground
commands transmitted in the blind to the spacecraft.
Four of the passes resulted in non-functional AACS
configurations, and thus would always lead to additional
passes. At least 2 of the configurations reedit should
have been functional, but failed to recover the signal.
o Two of the possible functional configurations were
probably seriously affected by a bad Overlay buffer
received from CDS-B as a residual effect of the first
Loss of Signal incident. The precise effect of this bad
Overlay buffer on the spacecraft's dynamic behavior
during the incident is not yet known.
o The ground commands transmitted were:
- First, a forced swap to IODA-A after approximately
7 hours without signal; and
- Second, a sequence of commands to disable Heartbeat
Loss Response, turn both AACS memories on, and
start ROM safing in memory A.
It is clear that the second sequence of commands caused
the recovery of the spacecraft signal.
o It is not clear to what extent the two Loss of Signal
incidents are logically connected. They started in
different hardware configurations, while executing
different software. (Note that the RAM and ROM software
are substantially different, and were developed with
purposeful independence to reduce the likelihood of
common errors.) However, the two incidents are
sufficiently similar to cause serious suspicion of a
common cause affecting Heartbeat loss.
7. Evidence from Testing Prior to Launch and in the Systems Verification
Lab (SVL)
o Prior to launch, the Magellan spacecraft showed a number
of hardware and software problems which could have caused
symptoms such as those seen since arrival at Venus. Some
were unverified and could not be repeated, while others
were identified and fixed. All were formally reviewed
and dispositioned prior to launch.
o Since launch, two incidents have been seen in SVL testing
during which the AACS ceased operating. It has not been
possible to reproduce nor to diagnose either of these incidents.
- The first occurred during testing of the VOI block.
The operators observed that a visible indicator
light showing correct execution of the 30 Hertz
interrupt service routine went out, and subsequently
the CDS executed the Heartbeat Loss Response.
- The second occurred during testing of the In-Orbit
Checkout 236 command load and caused CDS Heartbeat
Loss Response without the operators noticing
whether the visible indicator light had gone out.
Both SVL incidents were tentatively identified as due to
power supply fluctuations. Repeated attempts to
reproduce them were unsuccessful.
8. Speculations
o There is some evidence that during the first Loss of
Signal incident the AACS CPU suffered "cycle slipping"
for approximately 8 seconds. This would result from a
software problem causing failure to complete each 30
Hertz cycle prior to arrival of the next interrupt.
o There is some evidence that during the second Loss of
Signal incident the AACS CPU began execution in RAM.
This should not have been possible due to the purposeful
alteration of the Checksum words in both RAMS by the Trap
instruction at the end of the first incident.
o It is possible that the AACS-B memory address fault
occurred at the same time as the Pyro Switching Unit (PSU) was
turned off after detonating the SRM explosive bolts. The
Project is investigating the precise current paths
involved in the PSU circuit, including any fault paths.
o The Project is also investigating all the signal lines
opened at the time of SRM separation to determine whether
any of them could be sensitive to either shorts, opens,
or electrostatic charging events.
o Careful review of the Venus plasma environment has made
it appear highly unlikely that the spacecraft is
suffering any major charging or high energy particle
events which could have caused then observed faults.
9. Review Conclusions
o The Project should return to operation in RAM as quickly
as possible. This conclusion is based on:
- As much as possible has been learned already from
the spacecraft in ROM execution;
- The spacecraft is no less vulnerable to whatever
caused the two Loss of Signal incidents in ROM than
it is in RAM;
- The spacecraft is vulnerable to a number of
plausible single failures which would be fatal in
ROM but could be tolerated in RAM; and
- Return to RAM will substantially improve visibility
into AACS operations, and is necessary in order to
eventually play back the telemetry recorded on the
spacecraft tape recorders.
o The Project should attempt to determine the best method
to return AACS-B memory to a reliably usable
configuration. In particular, it should consider:
- A reprogramming of both AACS RAM memories to avoid
the un-trustworthy areas seen during the SRM
separation address fault in memory B;
- A reprogramming of AACS-B memory only to avoid the
faulted area; or
- A special "safe harbor" program for memory B only
in order to start radar mapping operations as quickly
as possible with some AACS-B memory redundancy.
o The next review (Friday, September 7) should address the
return to radar operations and the start of mapping.
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 09/01/90
Date: 4 Sep 90 02:10:52 GMT
Organization: Jet Propulsion Laboratory, Pasadena, CA.
Magellan Status Report
September 1, 1990
During the morning of September 1, a series of commands was
transmitted to the Magellan spacecraft to correct a number of attitude
control parameters to the values necessary to resume execution of the
normal control program within the Attitude and Articulation Control
Subsystem (AACS) computer. In addition, the Heartbeat Loss Response
table was slightly modified to cause the immediate next executions to
perform the precise component reconfigurations desired in case the
spacecraft again sensed Heartbeat Loss. Finally, transmitted a
command string was transmitted to reset the Checksum word in the AACS
memory permitting return to execution of the RAM program.
At 10:43 AM PDT, the spacecraft telemetry changed to indicate
that the AACS had correctly resumed RAM execution. The signal level
did not alter, indicating that the spacecraft did not change its
pointing at all. In addition, temperatures, battery voltages, and all
other telemetry remained stable. The spacecraft appears to be
performing entirely correctly.
Return to RAM execution in the AACS is the first step in the
return to normal spacecraft operation and the start of the radar
mapping mission. Next week, the Project will switch off the hydrazine
thrusters currently controlling the spacecraft pointing and return to
use of the electrically powered momentum wheels. It will then start a
series of star scans to determine the precise spacecraft attitude, in
preparation for repointing the High Gain Antenna (HGA) toward Earth.
After return to the HGA radio link, the spacecraft tape recorders will
then be replayed in order to recover the recorded engineering
telemetry from the start of the first Loss of Signal incident and the
radar instrument data from the second orbit of the Radar Test.
If no further difficulties are found, the Project expects to
restart radar operations between the middle and end of September. The
plan will be to start radar operations with the collection of data in
a normal mapping mode. However, it should be recognized that the
fundamental cause of the two Loss of Signal incidents since arrival at
Venus is still not known, and that another similar incident is
possible. The Project is prepared to respond as rapidly as possible
to any such incidents.
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
|
| 456.147 | MAGELLAN Update - September 4 | ADVAX::KLAES | All the Universe, or nothing! | Wed Sep 05 1990 14:02 | 86 |
| From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 09/04/90
Date: 4 Sep 90 23:15:43 GMT
Organization: Jet Propulsion Laboratory, Pasadena, CA.
Magellan Status Report
September 4, 1990
1. The Magellan spacecraft currently remains stable with its
Medium Gain Antenna (MGA) pointed toward Earth, its solar
arrays pointed toward the Sun, and its batteries fully
charged. Both Command Data System (CDS) computers are
operating. The spacecraft is using its hydrazine thrusters
for attitude control.
2. On Saturday, September 1, the spacecraft was commanded to
return to Attitude and Articulation Control Subsystem (AACS)
execution in RAM in the A memory. This was accomplished by
first updating critical attitude control parameters in the A
memory and then resetting the Checksum Work to the
hexadecimal value DEAD. The AACS computer immediately
recognized the correct value for the checksum and initiated
RAM execution.
3. The return to RAM processing in the AACS was shown
immediately by the resumption of the normal AACS telemetry
stream, which is much more detailed than that available
during ROM processing. No changes were seen in signal
levels, temperatures, or voltages, indicating that the
transition was performed correctly, without any unexpected
spacecraft motion.
It is interesting, but not thought directly relevant to the
spacecraft anomalies seen since arrival at Venus, that
gyroscope B2 appears to be producing normal channel outputs,
rather than being stuck at full scale on both channels. It
continues to show evidence of "chatter" in its motor
current. B2 motor current was turned back on automatically
during the ROM safing at the end of the first Loss of Signal
incident.
4. The spacecraft has remained stable, operating quiescently
but correctly over the Holiday weekend. The return to AACS
RAM processing was specifically performed before the weekend
so as to achieve the greater robustness against a range of
single-point attitude control failures provided by the more
sophisticated RAM program. The Project maintained full team
staffing for approximately 8 hours after the transition in
order to ensure that any faults could be corrected, or the
spacecraft recovered into ROM processing.
5. During the coming week, the Project intends to return the
spacecraft to reaction wheel control and turn off the
hydrazine thrusters. A series of star scan maneuvers will
then be performed to establish precise knowledge of the
spacecraft pointing. The High Gain Antenna will then be
pointed toward Earth, permitting the spacecraft tape
recorders to be replayed. The tape recorders currently hold
not only the second half of the second Radar Test orbit's
instrument data, but also engineering telemetry which was
being recorded during the start of the first Loss of Signal
incident. This data may provide vital clues to the basic
cause of the incident.
6. The Project conducted a review of the anomalies seen since
arrival at Venus on August 29. The basic causes of the two
Loss of Signal incidents are still not known, although a
good sequence of events is available for the first incident,
and the start and end of the second incident are reasonably
well understood. The review strongly endorsed a rapid
return to RAM processing.
A second review of the plan and schedule for return to radar
operations and the start of mapping is scheduled to take
place on Friday, September 7. A principal topic will be the
best means to use the AACS-B memory to provide safety for
mapping operations.
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
|
| 456.148 | | 19458::FISHER | Locutus: Fact or Fraud? | Wed Sep 05 1990 18:35 | 4 |
| I like the checksum value. How much you want to bet some hacker engineer
inserted a noop somewhere just to make it come out that way!
Burns
|
| 456.149 | MAGELLAN Update - September 5 | ADVAX::KLAES | All the Universe, or nothing! | Thu Sep 06 1990 13:39 | 143 |
| From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 09/05/90
Date: 5 Sep 90 21:39:45 GMT
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
September 5, 1990
The Magellan spacecraft is about 153 million miles from Earth
today with one-way light time of 13 minutes, 39 seconds. The
spacecraft is in stable operation in RAM attitude control today and
all telemetry is normal.
Last evening, engineers performed a read-out of a memory on the
spacecraft's Attitude and Articulation Control Subsystem (AACS). Also
flight controllers turned on the A-side star scanner and loaded a
mini-sequence for the return to reaction wheel control.
Also today, a self-test of the A-side star scanner was performed.
Before the test, the scanner was instructed not to try to switch to
the B-side star scanner if the test failed.
On September 6, the maneuvering ability of the spacecraft will be
tested by a Medium Gain Antenna (MGA) calibration. The spacecraft will
be moved about 10 degrees in each of two axes while the signal is
precisely monitored by the Deep Space Network (DSN).
If successful, star searches will be resumed and the spacecraft
will continue daily reaction wheel desaturations and star
calibrations. On Wednesday September 12, Magellan will be switched to
the High Gain Antenna (HGA) and will play back the tape recorded data.
That telemetry will include some engineering data that has been
stored since the first loss of signal event on August 16, and may help
project engineers determine the cause of the problem.
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update #2 - 09/05/90
Date: 6 Sep 90 00:23:58 GMT
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
September 5, 1990
The Magellan spacecraft continues stable operations in RAM control
with no further incidents. Yesterday evening, a memory readout of
non-write protect memory was performed along with turning Star
Scanner-A on and loading a "mini sequence" for return to reaction
wheels which will be initiated today. Before this test, Star
Scanner-A will be made prime so that failure of the self test will not
cause a switch to Star Scanner-B.
Tomorrow a Medium Gain Antenna calibration will be conducted to
test the Attitude Control maneuver ability. If successful, then star
calibrations will be initiated. The spacecraft is scheduled to
continue daily reaction wheel Desats and Starcals to Wednesday,
September 12, when it is planned to switch to the High Gain Antenna
and playback the tape recorder data.
An Investigation Team meeting tomorrow from 12:30 to 4:30 will address:
o Spacecraft grounding, Solid Rocket Moter (SRM) termination analysis,
spacecraft configuration changes.
o Attitude and Articulation Control Subsystem (AACS) grounding and
interfaces.
o Spacecraft charging.
o Memory-B failure analysis and tests.
o Memory-B patch to acquire telemetry insight to performance.
o Software analysis.
o System fault protection plans.
o Potential AACS software modifications and plans.
Commands Executed Tuesday night, September 4 (all times PDT):
o Telemetry Variable Format Update 17:45PM
o Turn On Star Scanner A 17:50PM
o Load Commands for Momentum Wheel Desaturations 17:55PM
o Read Out AACS Non-Write-Protected Memory 19:29PM
o Read Out AACS Non-Write-Protected Memory 22:55PM
All commands were transmitted on schedule and executed properly.
Assessment of the AACS non-write-protected memory readouts is
continuing. Star scanner A data is now available in the telemetry
stream and appears normal.
Commands Planned for Wednesday, September 5
o Turn off hydrazine thrusters
o Set Star Scanner A as Default
o Self-Test of Star Scanner A
o Enable Reaction Wheel Control
o Initiate Momentum Wheel Desaturation Controller
Commands Planned for Thursday, September 6
o Load and initiate Medium Gain Antenna Scan of Earth
o Load Star Search Parameters
o Configure Tape Recorder and Readout AACS Parameters
o Initiate Star Search
o Reset Star Search Parameters
o Load Star Scan Controller Sequence
o Initiate Star Scan Controller Sequence
The timing for commands on Wednesday and Thursday is not yet
certain due to continued negotiations for Deep Space Network (DSN)
70-meter antenna uplink time.
The review planned earlier for Friday, September 7 has been
delayed and a new date is not yet known.
Navigation processing of four revolutions of two-way coherent
Doppler tracking of the spacecraft, at S-Band on August 29, indicates
that the Magellan orbit parameters before and after the two spacecraft
anomalies are as follows:
Orbit as a result of What would have been
thrusting during spacecraft if no spacecraft anomalies
anomalies
----------------------------- ---------------------------
Period: 3.2595 hours 3.2637 hours
Periapse Alt: 290.7 km 295.7 km
Periaspe Lat: 9.5 degrees N 9.6 degrees N
Inclination: 85.4 degrees 85.5 degrees
It should be noted that all orbit parameters moved in a favorable
direction.
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
|
| 456.150 | | 19458::FISHER | Locutus: Fact or Fraud? | Thu Sep 06 1990 14:14 | 14 |
| Does anyone know how the "coning" search for Earth works? I.e. how does
Magellan know that it has found earth? Does it assume that Earth is sending
a beacon? Or is it (I don't think so) based on some optical thing.
Also, I take it that even the low-gain transmitting antenna is directional,
right? Is there no omni antenna? It seems to me that the Viking orbiters
had an omni antenna. It could only send a few bits per second, but it was
there, nonetheless. (Remember the V2 landing? Just as it was starting down,
the orbiter tumbled (or at least lost its lock with Earth). They did not get
it back till after the landing was done, but they could tell the landing was
successful because they noticed a change in data rate from the omni antenna,
even though they were not properly configured to actually receive the data.)
Burns
|
| 456.151 | MAGELLAN Update - September 6 | ADVAX::KLAES | All the Universe, or nothing! | Fri Sep 07 1990 13:48 | 48 |
| Date: 6 Sep 90 21:15:33 GMT
From: (Ron Baalke)
Subject: Magellan Update - 09/06/90
MAGELLAN STATUS REPORT
September 6, 1990
The Magellan Project is on schedule in its plan to resume radar
operations. The Magellan spacecraft remains stable in RAM attitude
control. On September 5, flight controllers successfully switched
from thruster to reaction wheel attitude control. A reaction wheel
desaturation also was accomplished and additional desaturations will
occur every four orbits.
A Medium Gain Antenna (MGA) calibration test was being performed
today to determine the extent of attitude offset. In the test, the
spacecraft is moved up and down the antenna pattern. If the calibration
is successful, the project will begin to conduct test star calibrations
through September 9.
The next step will be a mini-sequence with star calibrations and
desaturations on Monday and Tuesday, September 10-11, next week. The
change to the High Gain Antenna (HGA) is scheduled for next September
12 and then the tape recorder will be played back.
Engineers have identified two basic problems in the Attitude and
Articulation Control Subsystem (AACS) since orbit insertion. They
include an intermittently stuck bit in an address in the B-side
memory. That affects 2,000 to 4,000 bits out of the 32 thousand bit
memory. The problem occurred 7.3 seconds after separation of the Solid
Rocket Motor (SRM) on Aug. 10.
The second problem is that both the A-side and B-side computers
have intermittently executed incorrect instructions. The most likely
cause of the intermittent computer operations is thought to be noise
interference, possibly on the ground lines. The project is
investigating the change in spacecraft configuration after rocket
motor separation and the possibility of spacecraft electric discharges
as a cause of the noise. They are specifically investigating
unterminated wires that may have resulted from separation.
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
|
| 456.152 | Explanation please..... | 7401::LEBEL | | Fri Sep 07 1990 14:54 | 5 |
| Could someone give a brief description of "reaction wheels" and
the related references to "desaturation" etc.
GL
|
| 456.153 | Reaction Wheels | 15372::LEPAGE | Caught between Iraq & a hard place | Fri Sep 07 1990 15:13 | 9 |
| Re:.152
"Reaction wheels" are basicly gyroscopes used to store angular
momentum. Instead of using attitude jets to change its attitude,
Magellan can make use of the angular momentum stored in the reaction
wheels to turn. I believe I explained "desaturation" 15 months ago in
reply 456.21.
Drew
|
| 456.154 | | 7401::LEBEL | | Mon Sep 10 1990 14:37 | 2 |
|
Thanks.
|
| 456.155 | MAGELLAN Updates - September 6-7 | ADVAX::KLAES | All the Universe, or nothing! | Mon Sep 10 1990 17:40 | 118 |
| From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 09/06/90
Date: 6 Sep 90 21:15:33 GMT
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
September 6, 1990
The Magellan Project is on schedule in its plan to resume
radar operations. The Magellan spacecraft remains stable in RAM
attitude control. On September 5, flight controllers successfully
switched from thruster to reaction wheel attitude control. A reaction
wheel desaturation also was accomplished and additional desaturations
will occur every four orbits.
A Medium Gain Antenna (MGA) calibration test was being performed
today to determine the extent of attitude offset. In the test,
the spacecraft is moved up and down the antenna pattern. If the
calibration is successful, the project will begin to conduct test
star calibrations through September 9.
The next step will be a mini-sequence with star calibrations and
desaturations on Monday and Tuesday, September 10-11, next week. The
change to the High Gain Antenna (HGA) is scheduled for next September 12
and then the tape recorder will be played back.
Engineers have identified two basic problems in the Attitude
and Articulation Control Subsystem (AACS) since orbit insertion. They
include an intermittently stuck bit in an address in the B-side
memory. That affects 2,000 to 4,000 bits out of the 32 thousand
bit memory. The problem occurred 7.3 seconds after separation of
the Solid Rocket Motor (SRM) on Aug. 10.
The second problem is that both the A-side and B-side
computers have intermittently executed incorrect instructions.
The most likely cause of the intermittent computer operations is
thought to be noise interference, possibly on the ground lines.
The project is investigating the change in spacecraft
configuration after rocket motor separation and the possibility
of spacecraft electric discharges as a cause of the noise. They
are specifically investigating unterminated wires that may have
resulted from separation.
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 09/07/90
Date: 7 Sep 90 20:40:35 GMT
Organization: Jet Propulsion Laboratory, Pasadena, CA.
Magellan Status Report
September 7, 1990
The Medium Gain Antenna (MGA) scans of Earth were delayed due to
uplink difficulties experienced at Goldstone. The Canberra 70 meter
antenna observed the anticipated pattern of signal level variations
during the maneuvers. Analysis of the pattern seen indicates that
the spacecraft is currently pointed 2.9 degrees away from the
intended MGA-to-Earth attitude. This is well within the tolerable
MGA antenna pointing accuracy and is not surprising, since no star
scans have been performed since the start of the first Loss of
Signal incident. The Project is considering whether to update the
spacecraft attitude quaternion (on-board pointing estimate) prior to
initiating today's planned Star Scans. The commands for these Star
Scans are already on board the spacecraft ready to be initiated.
Analysis of the two Attitude and Articulation Control Subsystem
(AACS) memory readouts performed yesterday showed that the unexpected
single unused parameter value seen prior to return to reaction wheels was
in fact due to only a telemetry error, and that the actual memory contents
were as expected.
Star Scanner A as was set as the default so that the spacecraft will
not autonomously switch to Unit B in the case of another accidental Self
Test failure. The commanded Star Scanner self test worked correctly.
The Project conducted an internal review of the Problem Diagnosis
progress on Thursday, September 7. The next reviews will be on
Thursday, September 13, in presentations to JPL management of the
plans for restarting radar operations, followed by a telephone
presentation to NASA Headquarters. On September 20 an internal
Project review will be held at Denver, followed by a formal review
to be attended by JPL and NASA management at Denver on September 27.
Commands Executed Thursday, September 6 (all times PDT):
o Set Star Scanner A as Default 02:26PM
o Update Star Scan and Inertia Parameters 03:07PM
o Configure Spacecraft Tape Recorder B 03:23PM
o Perform Star Scanner A Self-Test 03:45PM
o Enable Delayed Engineering Data Collection 05:30PM
o Initiate Medium Gain Antenna Scans of Earth 05:35PM
o Load Maneuvers for Swath 1 and 2 Star Scans 08:30PM
o Load Commands for Star Scans 09:06PM
o Readout AACS Parameters 09:13PM
Commands Planned for today:
o Initiate Star Scans
o Reset Star Scan Parameters
o Load Star Scan Controller Sequence
o Initiate Star Scan Controller Sequence
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
|
| 456.156 | 1 Month Life Time ? | 42399::CHRIS | Capacity! What Capacity ? | Wed Sep 12 1990 09:57 | 8 |
| On Radio 4 PM a new flash stated that the Magellan probe had an
expected lifetime of 1 month. Could some please confirm this please ?
Cheers,
Chris
|
| 456.157 | One Month? | 15372::LEPAGE | Your oil dollars at work | Wed Sep 12 1990 14:59 | 10 |
| Re:.156
One month? Unless there has been some sort of catastrophic failure
that occured in the last 24 hours or so that I don't know about,
Magellan was designed for a minimum lifetime in Venusian orbit of about
eight months and is likely to last for a whole decade (barring major
systems failure).
Drew
|
| 456.158 | Rubbish News Report | 42399::CHRIS | Capacity! What Capacity ? | Wed Sep 12 1990 15:12 | 5 |
|
Thats what I thought BBC new has done it again...
Chris
|
| 456.159 | MAGELLAN Update - September 10 | ADVAX::KLAES | All the Universe, or nothing! | Thu Sep 13 1990 15:12 | 42 |
| From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 09/10/90
Date: 10 Sep 90 18:31:28 GMT
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
September 10, 1990
The Magellan spacecraft continued today in stable operations with
no further spurious attitude control operations. It is in RAM attitude
control on the Medium Gain Antenna (MGA) at 40 bits per second and
since the evening of Friday, September 7, has been using star
calibrations for attitude knowledge updates.
On September 7 the spacecraft was commanded to do a star search
and on the first maneuver the spacecraft successfully found both stars
-- Alpha Carinae and Alpha Tauri -- and effected an attitude update of
1.78 degrees. The project then activated a mini-controller program on
board the spacecraft that automatically calls for star calibrations on
every fourth orbit.
The spacecraft missed Alpha Carinae due to a magnitude error once
September 8 and once again on September 9, but was successful with
Alpha Tauri readings and other calibrations were successful.
The project is on schedule to switch to the High Gain Antenna
(HGA) on September 12, and to prepare for resumption of radar
operations on Saturday, September 15.
Gyro B-2, one of two redundant gyros, that had caused trouble
earlier was reported heating up and the motor current increasing. It
was to be turned off today. Loss of the gyro is not expected to have
any effect on the rest of the mission.
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
|
| 456.160 | MAGELLAN high-speed radio link restored | ADVAX::KLAES | All the Universe, or nothing! | Thu Sep 13 1990 20:26 | 62 |
| APn 09/13 0411 Magellan-Venus
By LEE SIEGEL
AP Science Writer
PASADENA, Calif. (AP) -- NASA restored a high-speed radio link with
Magellan that will allow a crucial test of the spacecraft on Saturday and
released more pictures of jagged lava flows and giant volcanic craters on
Venus.
Engineers Wednesday pointed Magellan's main antenna toward Earth,
putting the high-speed communications on line for the first time in four
weeks and using the link to send home the contents of the spacecraft's
tape recorder.
They they began analyzing the information for clues to why they lost
radio contact with the spacecraft for 14 hours starting Aug. 16 and for
17 1/2 hours starting Aug. 21.
Restoring the high-speed radio link was a key step toward letting
Magellan begin its $744 million mission to make highly detailed maps and
pictures of Venus using radar to penetrate the planet's thick clouds.
Engineers at NASA's Jet Propulsion Laboratory had been using a
secondary Magellan antenna to maintain contact with Earth. Engineers
figured that because the secondary antenna sends out a broader beam than
the main antenna, they would be less likely to lose contact with the
spacecraft if there were another glitch.
Because of the communication problems, Magellan was to start its
mapping mission late this month, about a month behind schedule.
But if all goes well during a radar test on Saturday, NASA might
simply pronounce the mapping under way then, said experiment
representative Steve Wall. The craft is 155 million miles from Earth
The three pictures released Wednesday were taken during an Aug. 16
radar test, just hours before contact with the craft was first lost.
One picture shows at least two irregularly shaped craters -- called
calderas -- similar to those atop Hawaii's Mauna Loa and Kilauea
volcanoes. The largest is 5 miles long and 2.2 miles wide.
The calderas were apparently created when lava flowed from vents and
caused the volcanoes' summits to collapse, said Steve Saunders, the
Magellan project's chief scientist.
Another picture shows a basalt lava flow 11 miles wide and at least 15
1/2 miles long. It has lobed edges, is extremely rough and probably
flowed in a "thick, pasty" manner before it solidified, Saunders said.
A third new picture shows a valley, about six-tenths of a mile wide,
that formed when a block of land dropped down between two faults as the
area was being stretched apart, Saunders said.
Similar fault-bounded valleys are found in California, East Africa and
Germany.
Magellan went into orbit around Venus last month after traveling a
looping, 948-million-mile path since its launch from the shuttle Atlantis
in May 1989.
|
| 456.161 | MAGELLAN Updates - September 11-13 | ADVAX::KLAES | All the Universe, or nothing! | Fri Sep 14 1990 14:19 | 233 |
| From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 09/11/90
Date: 11 Sep 90 19:25:16 GMT
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
September 11, 1990
The Magellan spacecraft continues stable in RAM attitude control
on the Medium Gain Antenna (MGA) today, and is using star calibrations
for attitude knowledge updates.
Yesterday, the spacecraft performed a successful star calibration
with an attitude update of 0.74 degrees but later in the day again
failed to accept one of the stars, Alpha Carinae, because of a
magnitude error.
The command approved to turn off the B-side 2 gyro was
transmitted last night but telemetry indicated the gyro was not turned
off. The command process was apparently successful as far as the
Attitude and Articulation Control Subsystem (AACS) computer. There was
a problem in completing the command, possibly an electrical or
mechanical failure. Engineers are working on the problem and the
command will not be transmitted again until it is understood.
Plans continued today to change to the 62.5 bits per second
command uplink along with the uplink of command sequence 255 which is
to go into operation Wednesday, September 12. It will turn on the High
Gain Antenna (HGA) transmitter and point the antenna to Earth so the
contents of the tape recorder, containing both engineering and radar
data, can be played back.
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 09/12/90
Date: 12 Sep 90 22:56:10 GMT
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
September 12, 1990
The Magellan spacecraft was turned today to point the High Gain
Antenna (HGA) to Earth for a playback of the second half of the second
test mapping orbit of August 16. The data, along with engineering data
for 55 minutes prior to the first loss of signal to five minutes after
the loss also was on the tape recorder.
Playback would begin early this afternoon and data is expected in
hand later in the day. Analysis will begin which may help them
determine the cause or causes of the first loss of signal.
The HGA will playback radar data on X-band at the highest rate of
268.8 kilobits and engineering telemetry at 115 kilobits per second.
The radar data will be processed on September 13 an 14. The project
plans to resume test mapping of Venus on Saturday, September 15.
The spacecraft is now operating on the new command sequence, 255,
which was uplinked last night.
The star calibration yesterday morning was fully successful, but
a calibration later in the day again missed one of the guide stars.
However, the problem which caused the rejections is now believed to be
corrected.
Gyro B-2 remains on despite a command sent earlier to turn it off
and the temperature has increased. But the spacecraft team said there
was no urgency in the situation.
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 09/13/90
Date: 13 Sep 90 16:12:41 GMT
Organization: Jet Propulsion Laboratory, Pasadena, CA.
Magellan Status Report
September 13, 1990
1. Return to High Gain Antenna
On Wednesday, September 12, the Magellan spacecraft returned to
normal stored sequence control from the Command Data System (CDS)
computers at 6:14 AM PDT. At 10:29 AM, the spacecraft initiated the
turn from Medium Gain Antenna (MGA) to High Gain Antenna (HGA) toward
Earth, so that the MGA signal was lost. The signal was reacquired from
the HGA at the high 1200 bps realtime telemetry rate at about 11:00 AM
PDT. The maneuver was performed correctly and all telemetry was normal.
2. Tape Recorder Playback
After the turn to the High Gain Antenna, the spacecraft initiated
the first of a continuing sequence of once-per-orbit star scans.
(Star scans have been performed once every 12 hours since Friday
evening.) The first scan successfully found both target stars and
provided an attitude correction of approximately 0.6 degrees. At
12:30 AM PDT the first of a set of four tape recorder playbacks at
115 kbps started through the Goldstone Deep Space Network (DSN)
station. The first two of these playbacks covered the engineering data
which was being recorded before the start of the first Loss of Signal
incident. The data from these playbacks was received successfully and
transferred simultaneously by communication line to JPL. The first two
playbacks were repeated at 268 kbps later in the evening over the
Canberra DSN station.
The engineering data from these playbacks is currently being
processed through the Space Flight Operations Center (SFOC) system and
loaded into the Project's Central Data Base, from which it can be read
by the spacecraft team. Analysis of the data, and particularly the search
for any indication of the cause of the start of the Loss of Signal
incident, is expected to be completed by noon on Thursday, September 13.
In addition, approximately half of the residual second half of the
data from the second orbit of the Radar Test was also recovered in
the first two playbacks and will be processed into imagery through
the Production Synthetic Aperture Radar (SAR) Processor this morning.
The remainder of the Radar Test second orbit data will be played back
on Saturday, September 15, before the start of new radar operations.
3. Plans
On Thursday, September 13 the spacecraft will continue the series of
star scans on every orbit and reaction wheel desaturations every
four orbits, but no other special events are planned. The Project
will conduct a pair of presentations to JPL and NASA management to
explain its plans to proceed to re-start radar operations. On
Friday, September 14, the radar instrument will be turned on and
perform a self test at 8:14 AM PDT. The radar will then be left in
standby mode until Saturday, September 15 at 11:29 AM PDT, at which
time radar operations will be started.
The radar will be operated in normal mapping mode, rather than the
special test mode used in the previous Radar Test. (The data swaths
collected will lie along the center of the antenna illumination
pattern, and run parallel with the antenna pattern's path along the
ground, rather than running diagonally across the antenna pattern.)
The Project will treat this data as normal mapping operations, and
expects to be able to process it into mosaics of large areas.
At a later time, normal mapping may be interrupted for a short
(approximately 2 orbit) test sequence designed to permit accurate
calibration of antenna pointing, Doppler spectrum, and ground
reflectivity patterns. The aim of all these radar operations will
be to achieve the full intended mapping performance as rapidly as
possible, with the earliest and most complete possible mapping
coverage.
4. Gyroscope B2
An unexplained anomaly occurred on Monday evening at 5:30 PM PDT,
September 10, when a command to the spacecraft to turn off gyroscope
B2 was apparently unsuccessful. Gyroscope B2 is the unit which
initially showed evidence of "bearing chatter" through increasing and
variable drive motor current and increased scatter in its drift rate.
In order to conserve the unit's mechanical life, the drive motor was
turned off during cruise. When the drive motor was turned back on
in preparation for Trajectory Correction Maneuver 3 (TCM-3), both of
the rate sensing axis outputs were observed to show full scale
(saturated) readings. This was interpreted as a failure within the
gyroscope sensing electronics, and the drive motor was again turned
off and the unit marked as "not available" to the Attitude and
Articulation Control Subsystem (AACS). The entry into ROM safing at
the end of the first Loss of Signal incident autonomously turned B2's
drive motor back on. After recovery of the spacecraft, a memory readout
showed that B2 was producing normal telemetry readings from both output
channels.
Since return to AACS RAM processing, telemetry has shown continued
normal output channel readings from B2, but also evidence of
continued bearing chatter and drive motor current instability. The
B2 temperature has also increased, although not to dangerous levels.
The gyroscope manufacturer (Kearfott) had advised the Project that
higher temperatures might eliminate the chattering by reducing the
viscosity of the bearing lubricant, but this behavior has not yet
been seen. The Project decided to turn B2's drive motor off through
the same command file used previously.
The file has not only worked before, but has also been re-verified
in the Denver Systems Verification Lab (SVL). The commands appear
to have executed properly, since the software table recording the
status of gyroscope B2 changed to show it "off". This change is
performed only after the command to switch the controlling relay is
performed. In addition, the command handshaking between the AACS CPU
and the Input-Output Drive Assembly (IODA) did not record any failed
commands: either no command was sent by the CPU, or a "valid" command
was received by the IODA. It is possible that the "valid" command
received was erroneous; some valid addresses within the IODA are unused,
and would produce no noticeable responses.
The actual gyroscope drive motor control is performed by a pair of
relays in IODA A and B. Both relays must be "off" to turn the motor
off. A second set of contacts on each relay shows the relay state:
despite the command to turn off, the IODA A relay contacts still
show the relay to be on. In addition, the B2 motor current
telemetry also shows the unit to be on.
At least two plausible mechanisms could have caused this
misbehavior. The AACS CPU(A)-IODA(A) command transfer could have
been garbled, possibly by a similar mechanism to that which has
caused the two Loss of Signal incidents, or the IODA(A) motor
control relay could have failed on. Since there is no urgency to
turn B2 off, the unit will be left in its current state while the
reasons for this behavior are considered further.
It would be highly desirable to be able to keep gyroscope B2 in
operation if possible in order to improve the spacecraft's
robustness against failure of one of the other three gyroscopes. In
order to return the unit to service, the most important
consideration is not bearing chatter, but rather the likelihood of a
reappearance of the saturated output channel readings seen earlier.
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
|
| 456.162 | MAGELLAN Updates - September 15-18 | ADVAX::KLAES | All the Universe, or nothing! | Fri Sep 21 1990 15:42 | 419 |
| From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan News Conference
Date: 20 Sep 90 17:26:44 GMT
Organization: Jet Propulsion Laboratory, Pasadena, CA.
PUBLIC INFORMATION OFFICE
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIF. 91109. TELEPHONE (818) 354-5011
A Magellan news conference will be held at the Jet Propulsion
Laboratory's von Karman Auditorium at 10 a.m. PDT, Tuesday, Sept. 25.
New radar images of the surface of Venus will be released. A video
tape of a computer-processed series of images also will be shown.
Project officials will discuss the status of the spacecraft and
members of the science team will interpret Venus surface features seen
in the radar images. The news conference will be carried on NASA
Select, Satcom F-2R. For further information call the JPL Public
Information Office at the above listed number.
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 09/15/90
Date: 20 Sep 90 22:23:20 GMT
Organization: Jet Propulsion Laboratory, Pasadena, CA.
Magellan Status Report
September 15, 1990
The Magellan spacecraft is currently 250 million kilometers
(156 million miles) from Earth. Radio signals take 13 minutes and 53
seconds to travel each way between Earth and Venus.
On Saturday, September 15, the Magellan spacecraft started
normal radar mapping operations. This marks the completion of
recovery from the anomalies which have affected the spacecraft
since arrival at Venus on August 10, and the start of the
progressive mapping of the surface of the planet.
All of the radar mapping operations were performed under the
control of a stored sequence onboard the spacecraft. The
spacecraft turned its High Gain Antenna (HGA) away from Earth at 9:29
AM PDT in preparation for the start of radar mapping. The radar
began to illuminate Venus at 9:35 as it passed over the planet's
North pole. At 9:53, the spacecraft passed through the closest
point to Venus on its orbit behind the planet as seen from Earth,
in shade from the Sun on Venus's night side. At 10:13, the radar
completed its data collection in the Southern hemisphere. All of
the radar data was stored onto the two spacecraft tape recorders
during the radar illumination.
The spacecraft then turned to point its High Gain Antenna
back toward Earth. At 10:26 AM PDT, the signal was reacquired at
the Goldstone Deep Space Network (DSN) station, using two 34 meter
antennas connected together in an array. All telemetry
indications were completely nominal. Playback of the radar data
from the first spacecraft tape recorder started at 10:27.
At 11:24 AM, after playing back the first tape recorder, the
spacecraft again turned away from Earth to perform a star scan in
order to correct its inertial attitude control. The star scan
was successful, with a very small attitude correction of 0.017
degrees. The spacecraft signal was again re-acquired at Goldstone
at 11:38. Playback of the second spacecraft tape recorder was
completed at 12:45 PM.
This sequence of activities will be repeated continuously
for the duration of the mapping mission. Today, approximately
2.5 full mapping orbits of radar data will be acquired at the
Goldstone station. The spacecraft signal will then be handed
over to the Canberra DSN station in Australia, and subsequently
to the Madrid station in Spain. Data from the initial Goldstone
orbits will be processed into imagery over the weekend. Each
orbit of the spacecraft around Venus takes just over 3.26 hours.
Venus will slowly rotate beneath the spacecraft's orbit so that
the radar will successively image the entire planet over the next
8 months.
Before the start of radar operations, the Magellan Project
completed the playback of all the radar data and engineering
telemetry stored on the spacecraft tape recorders before the
start of the previous anomalies. This data will be carefully
analyzed for evidence of the source of the problems. The Project
has carefully prepared both the spacecraft and ground systems to
respond quickly and safely to any reoccurrence of the faults.
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 09/17/90
Date: 20 Sep 90 22:24:13 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
September 17, 1990
The Magellan spacecraft is operating normally under control
of a stored computer sequence today and Venus mapping, begun last
Saturday, September 15, is continuing.
Several elements of the spacecraft fault protection system
have been modified to improve the probability of either riding
through, or recovering rapidly from, any recurrence of the
problems experienced during the past month.
The Attitude and Articulation Control Subsystem (AACS) B-side RAM
has been marked unusable until further diagnosis has been completed,
and its contents have not been reloaded. Also, ground commands and
procedures to recover and restart the spacecraft in the event of loss
of signal are available for immediate use.
Achieving this status represents a major set of milestones.
Over the course of the past week, the project successfully conducted
a series of star scans to achieve accurate spacecraft pointing, turned
the High Gain Antenna (HGA) toward Earth, and read out the tape recorded
engineering and instrument data from before the first loss of signal
event on August 16.
At 9:29 a.m. PDT September 15, Magellan turned the HGA away from
Earth and started its first radar mapping orbit. Radar data from two and
one-half orbits were acquired at Goldstone through a pair of arrayed
34-meter Deep Space Network antennas. Since that time the spacecraft has
continued its radar orbit sequence without problems.
Also on the evening of September 15, a command was sent to the
spacecraft to slightly raise the battery voltage to maintain a
reasonably warm temperature. The level of battery voltage at the end
of radar operations while behind the planet, and when shaded by the
HGA, was found to be lower than it should be as a result of cooling.
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update #2 - 09/17/90
Date: 20 Sep 90 22:25:03 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
September 17, 1990
1. Spacecraft Status
The Magellan spacecraft is operating nominally under the
control of a stored sequence in the two Command Data
System (CDS) computers. It is performing radar mapping
operations using the normal radar control parameters on
each orbit, including radar illumination of Venus, data
recording and playback, a star scan on each orbit, and
dumping of stored angular momentum from the reaction
wheels on every fourth orbit. The Attitude and
Articulation Control Subsystem (AACS) is operating
nominally on its A-side components.
Several elements of the spacecraft fault protection
system have been modified so as to improve the
probability of either riding through, or recovering as
rapidly as possible from any reoccurrence of the problems
seen previously. The AACS B RAM memory has been marked
unusable until further diagnosis has been completed, and
its contents have not yet been reloaded. In addition,
the ground commands and procedures to recover and restart
the spacecraft are available for immediate use. It was
judged that radar mapping operations were safe and reason-
able given these measures to protect the spacecraft.
Achieving this status represents the accomplishment of a
major set of milestones. Over the course of the week,
a series of star scans were conducted successfully to
achieve accurate spacecraft pointing, turned the High
Gain Antenna (HGA) toward Earth, and read out the tape recorded
engineering and instrument data from before the first
Loss of Signal incident.
2. Start of Radar Operations
At 9:29 AM PDT on Saturday, September 15, Magellan turned
the High Gain Antenna away from Earth in order to start
its first radar mapping orbit using normal radar
parameters. The signal was reacquired at 11:26 AM at
Goldstone through a pair of arrayed 34 meter DSN
antennas. Data replay from the spacecraft tape recorders
was performed normally, as was the star scan maneuver.
Since that time, the spacecraft has continued repeating
its radar mapping orbit sequence without any problem.
2.5 orbits of data were collected at Goldstone on
September 15 and transported to JPL that night. These orbits
were processed overnight into normal image strips.
Visual and engineering assessment of these image strips
is continuing, but the first indications are that the
radar performance was excellent.
The Project Science Group is assembled at JPL for working
meetings on September 17-18, so the new image data is
available immediately to the entire science team. The
scientists are extremely excited by the excellent quality
of the imagery and the range of interesting features
found on Venus's surface. The altimeter and radiometer
data products will be processed early in the week.
3. Battery Voltage at End of Occultation
A minor concern arose concerning the level of battery
voltage at the end of radar operations in Sun
occultation. Due to the current orbit geometry, the
spacecraft is quite cold, since it is shaded behind the
HGA during the entire data playback period. In addition,
the majority of the radar mapping period occurs in
occultation from the Sun, and the period of occultation
is near maximum. The battery heaters were found to cycle
on during occultation. These factors combine to leave
the battery voltage quite low at the end of occultation.
In order to alleviate this concern, a command was sent to
the spacecraft at 8:10 PM PDT on September 15 to slightly raise
the voltage to which it charged the battery at any given
temperature. This increased charging slightly increases
the battery temperature and state of charge at the start
of occultation. The Radar Team is continuing to monitor
the battery telemetry seen in the Delayed Engineering
Data from each orbit prior to receipt of the recorded tapes.
4. Slight Correction of Spacecraft Clock Time
A correction in the formula through which ground and
spacecraft clock times are converted was discovered
through a discrepancy in matching the periapsis times
from ground tracking with the periapsis times determined
from the radar altimeter data from the Radar Test. The
error (a 2/3 second delay) was caused by confusion over
the time tagging of telemetry blocks at the Deep Space
Network (DSN). The effect of the correction will be to
cause a small shift in the along-track (north-south) placement
of image features, and a small improvement in the time-alignment
of radar commanding. For the start of radar operations
on September 15, correction for the along-track displacement
was accomplished within ground data processing.
Correction of the spacecraft command timing will be
performed when the next command sequence is transmitted.
5. Gyroscope B2
Gyroscope B2 remains on, with the drive motor current
showing evidence of continuing chatter and the
temperature slightly high. The output attitude rate
readings remain normal. The failure of B2 to turn off on
command last September 10 evening remains under investigation.
A probable cause has been identified, due to overwriting
the turn-off command within the AACS Input Output Drive Assembly
(IODA) with a separate command to maintain the set status. The
frequency with which the "maintain status" command is sent was
increased at the time of Venus Orbit Insertion (VOI) to such a
level that the probability of overwrite is quite high.
6. Plans
An internal working meeting will be conducted at Martin Marietta
(Denver) on Thursday, September 20. A formal review of
the events, diagnosis, and suggested actions from the
anomalies seen since arrival at Venus will be held at
Martin on Thursday, September 17. The next planned
Project Press Conference will be conducted at JPL
on September 25.
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 09/18/90
Date: 20 Sep 90 22:25:53 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
Magellan Status Report
September 18, 1990
1. Spacecraft Status
The Magellan spacecraft continues to perform normal radar
mapping operations correctly. However, last night during a
period while the spacecraft was operating the radar and not
in immediate communication with the Earth (between 2:26 and
3:25 AM PDT), Command Data System-B (CDS-B) read a series
of 57 erroneous Alert Codes from the Attitude and Articulation
Control Subsystem B (AACS-B) memory. Since the AACS-B memory
is currently marked logically off, no such Alert Codes were expected.
The most probable explanation of the data is a re-occurrence of
the Memory B Address Problem first seen just after separation of
the Solid Rocket Motor (SRM) case. The 57 counts would have been
generated if the address problem reoccurred for 38 seconds, shifting
an unchanged memory bit pattern in such a way as to cause the CDS-B
to read erroneous Alert Codes.
The Project intends to send commands today to read out the CDS
"Alert Code Snapshot" memory, and also the suspect area of the
AACS-B memory. The CDS memory will record the time of the
last received Alert Code, while the AACS-B memory should show
evidence that the AACS Heartbeat and Spacecraft Clock words,
which are the only words being written into the AACS-B memory,
were written into the incorrect words (address bit 4 high).
This incident did not cause any other spacecraft actions, nor
interrupt the mapping sequence. A full playback of the
telemetry data (from the tape recorders) will be available
tomorrow. The principal implication is that the AACS-B memory
address fault appears to still be present occasionally.
2. Radar Operations
Radar data from 2 days of Goldstone receptions has now been
processed into imagery. The quality of these images appears
excellent, and the scientific analysis teams are actively
examining them. The scientists, the image processing team,
and the Synthetic Aperture Radar (SAR) processing team are
cooperating to investigate a number of minor possible corrections.
3. Analysis of Recorded Data from First Loss of Signal
The Martin Marietta spacecraft team reports that analysis of the
engineering telemetry which was being recorded at the time of
the first Loss of Signal incident has not (yet) revealed any
evidence of a prime cause. The AACS telemetry froze at the
time previously believed to be the start of Heartbeat Loss.
The first step of Heartbeat Loss Response forced a Power On
Reset and apparently restored correct AACS operation, since
the telemetry resumed its normal pattern. However, Heartbeat
Loss continued to force a swap to the AACS B components and
entry into RAM safing.
This evidence rules out certain possible causes of the Loss of
Signal incident, but does not show a prime cause. It also
does not reveal why the hardware "Watchdog Timer" circuit
failed to trip prior to Heartbeat Loss. It does, however,
improve the Project's confidence in the current state of the
Heartbeat Loss Response mechanism, which would attempt an
immediate restart of AACS operation by swapping the Input
Output Drive Assembly (IODA). This response would probably
cause the AACS to restart properly, immediately resynchronize,
and continue normal mapping without interruption.
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update #2 - 09/18/90
Date: 20 Sep 90 22:26:46 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
September 18, 1990
The Magellan spacecraft continues in standard radar mapping
operations providing 22 orbits of radar data since start-up of
radar operations on Saturday, September 15. Both the spacecraft
and radar are nominal.
Since Venus is almost the same size as Earth, 22 orbits of
data represents a patch of imaging that on Earth would range from
the Pacific coast out to Kingman, Arizona in width and in length
would extend from the North pole to almost the South pole.
Last night, between 2:26 AM and 3:25 AM PDT, the backup Attitude
control computer-B (AACS-B) sent alert codes to the backup main
computer (CDS-B) indicating anomalous operation for 38 seconds,
possibility the reoccurrence of the memory-B failure. Tape recorder
playback data may shed some light on this incident. There was no
impact to normal attitude control operations being conducted on
the main computer-A (CDS-A).
The 1st weekly mapping sequence upload will occur this
evening starting after 7:41 PM PDT. The next 8 day mapping sequence
will take effect tomorrow at 4:28 AM PDT.
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
|
| 456.163 | MAGELLAN Update - September 24; news items | ADVAX::KLAES | All the Universe, or nothing! | Thu Sep 27 1990 15:09 | 236 |
| From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 09/24/90
Date: 26 Sep 90 17:59:27 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
Magellan Status Report
September 24, 1990
The Magellan spacecraft continues in standard radar mapping
operations and have completed 66 orbits of mapping since September 15.
When mosaicked together, this 66 orbit patch would cover an area on
Earth extending from Los Angeles to Oklahoma City and from the North
pole to South pole. Each orbital strip is 15 miles wide, so this
represents a 990 mile wide patch (East-West direction), and extending
from both poles. 1,786 orbits of mapping data are required to cover
Venus, and 1.9 billion bits of radar data are collected on each orbit.
The Deep Space Network (DSN) has captured over 98% of the bits
radiated to Earth. The last glitch on the A-side of the Attitude and
Articulation Control Subsystem (AACS) occurred on September 3. Last
week, three occurrences of what is believed to be the Memory-B failure
were detected.
A review will be held on Thursday, September 27 at Martin
Marietta to cover the spacecraft problem investigations and long term
work around plans.
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
From: clarinews@clarinet.com
Newsgroups: clari.tw.space
Subject: Magellan probe successfully mapping Venus
Date: 25 Sep 90 19:24:30 GMT
PASADENA, Calif. (UPI) -- After a shaky start, the Magellan
probe is successfully mapping cloud-shrouded Venus, beaming back
``revolutionary'' views of a heavily fractured, volcanic planet that
may be geologically active, scientists said Tuesday.
A brief but dramatic movie made with Magellan data was
unveiled at a news conference that simulated a zooming 12-mile-high
flight above a tortured region of complex faults and fractures, giving
viewers a bird's eye view of a planet otherwise hidden from view.
Other photographs released Tuesday, including a giant 10-by-10
foot mosaic, show numerous volcanic craters, sharply defined Los
Angeles- sized impact craters and broad regions of cracked terrain
covered in places by lava flows indicating a possibly geologically
active planet.
``There's a lot of activity on Venus,'' said Brown University
researcher James Head. ``I think Venus is very much alive in the broad
sense. But actually being able to document changes that have occurred
in (recent) years is difficult to document.''
``It's reasonable to anticipate that there might be, somewhere
on the planet, volcanological activity occurring on the scale of days
to years to tens of years. But really, we have no way of detecting
that directly.''
With no water on the hellish 900-degree planet, erosion
appears to be remarkably minimal, giving scientists a chance to look
at large features that might otherwise be destroyed over time.
``This is a really interesting thing for Venus because we seem
to see very pristine forms ... that seem not to have been modified by
water-type erosion on the surface,'' Head said. ``This is going to
(permit) us to see lots of relationships that are essentially
destroyed on the Earth.''
Along with photographs from Magellan, scientists also revealed
data from a device called an altimeter that gave researchers a look
down into a 25-mile-wide, 1,640-foot-deep volcanic crater rising more
than 980 feet above the surrounding countryside.
``In the small amount of data we've seen so far, we've been
able to really look at the surface of Venus as sometimes 10, sometimes
100 times better (clarity) than we've ever seen before,'' Head said.
``Believe me, it's giving us a revolutionary new view of Venus.
``Literally, Magellan is a microscope on Venus. There's just
an untold wealth of data that's providing tremendous excitement.''
But engineers said they have been unable to figure out what
twice knocked the spacecraft out of contact with Earth last month.
``The problem ... may happen again,'' said John Slonski,
Magellan spacecraft systems engineer. ``By its nature, it's random.
We're putting into place procedures based on our experiences last
month that will allow us to recover in a much more rapid fashion and
minimize data loss.''
Even though one of Magellan's attitude control computer
systems has been declared unusable until a fix is devised, the
spacecraft was ordered to resume mapping operations Sept. 1.
Since then, officials said, Magellan has successfully
completed more than 82 mapping orbits, beaming back 50 hours of
priceless data to eager scientists on Earth. The mission to map 90
percent of Venus's surface is scheduled to last at least 243 days,
equivalent to one complete rotation of Venus around its axis.
Magellan, built by Martin Marietta Astronautics Group of
Denver, dropped into orbit around Venus Aug. 10, 15 months after
launch from the Space Shuttle ATLANTIS on May 4, 1989.
The 2 1/2-ton solar-powered satellite was designed to ``see''
through the clouds that perpetually blanket Venus by bouncing radar
beams off the planet's surface.
Extensive computer processing on Earth can convert such radar
data into photo-like images showing surface features as small as a
football field, some 10 times better than the best previous effort.
Magellan began mapping the surface of Venus on Aug. 16. But
after one and a half orbits, the spacecraft suddenly went into a
computer-induced state of hibernation and aimed its main antenna away
from Earth.
Contact was restored the next day, but it was lost again the
following week. Emergency commands radioed to Magellan ``in the
blind'' caused to spacecraft to search for Earth and communications
ultimately were restored.
Additional instructions were radioed to the probe later to
prevent it from going into such computer-induced hibernation and
losing contact with Earth if similar problems crop up in the future.
``The computer isn't completely well,'' Slonski said. ``The
backup memory, which exhibited a failure shortly after getting into
orbit, has had three instances of telemetry indications telling us the
problem has come back and then gone away three times.
``This has had no effect on operation because we have already
marked that computer as unusable until we have designed a work-around
program.''
Engineering data from the spacecraft ``has not shown us what
the root cause was,'' although it may be related to damage incurred
when the probe's braking rocket was kicked away after Magellan
achieved orbit.
``Our efforts are more oriented toward recovering from any
future occurances than having hope that we'll be able to prevent
them,'' he said.
From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Articles on New Magellan Images
Date: 26 Sep 90 18:09:39 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
USA Today -- 9/26/90
"Magellan Sending 'Jazzy' Venus Photos"
"The Magellan spacecraft is taking 'jazzy' pictures of cloudy planet
Venus. Scientists Tuesday said photos show windblown dust deposits, a
crater the size of Los Angeles, and a 200-mile-long solidified lava
river, suggesting an 'excellent possibility' a volcano exists."
--------------------
Washington Post -- 9/26/90
"Surface of Venus Surprisingly Active"
By Kathy Sawyer
"The face of Venus, Earth's hellish sister planet, is unexpectedly
alive with cataclysmic change, according to geologists' interpretation
yesterday of dramatic new images of the planet provided by the robotic
Magellan spacecraft."
The story describes the scientists interpretations and notes that
on Venus towering mountain ranges are thrusting up and collapsing,
sinuous rivers of volcanic lava have flowed for hundreds of miles and
meteors have blasted the deepest known crater in the solar system --
twice as deep as the Grand Canyon.
The story also notes that some of the lesser craters could swallow up
Washington and that one of the most mysterious features discovered yet
is a region of fractures and faults which intersect at angles
approaching the uniformity of graph paper.
The Post describes the scientific briefing where the new data was
presented and notes that the scientists are delighted with what
appears to be startling data of exceptional quality. The story quotes
geologist Jim Head, from Brown University, as declaring that Magellan
has given the science team a "microscope on Venus."
--------------------
New York Times -- 9/26/90
"Spacecraft's Images of Venus's Terrain Astonish Scientists"
By John Noble Wilford
"To the delight of astonished scientists, glimpses of Venus produced
in 10 days of mapping by the Magellan spacecraft show a surprisingly
active planet whose volcanoes, fractured landscapes and thin plastic
crust are unlike anything seen before in the solar system."
The Times story says the spacecraft has produced images between ten
and one hundred times as detailed as previous Soviet and American
missions to the planet and quotes one of the project scientists, Jim
Head of Brown University, as saying "it's a whole new world."
The story says scientists were surprised to see bright streaks across
some of the Venusian plains, indicative of wind-blown deposits because
the planet's atmosphere was thought to be too sluggish to create much
wind erosion.
The Times says that by orbiting while the planet slowly rotates beneath,
the spacecraft should map most of the surface of Venus in the next seven
months and that when the primary mapping is accomplished, the spacecraft
will repeat the task providing data which can be used to detect any
changes in the landscape and thereby possibly detect volcanic eruptions.
The story cites Gordon Pettengill, leader of the radar science team,
who reported that altimeter data from Magellan has shown one impact
crater to have walls more than two miles deep.
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
|
| 456.164 | MAGELLAN Update - September 26 | ADVAX::KLAES | All the Universe, or nothing! | Tue Oct 02 1990 16:22 | 70 |
| From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 09/26/90
Date: 28 Sep 90 18:32:18 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
Magellan Status Report
September 26, 1990
The Magellan spacecraft continues in standard radar mapping
operations and have completed 83 mapping orbits since September 15.
These 83 orbit images, when mosaicked together, will cover an area
approximately 1245 x 10,000 miles, and would cover an area on Earth
extending from Los Angeles to Oklahoma City and from the North pole to
the South pole. Magellan has imaged 5% of the planet Venus.
Radar mapping data acquisition was started on Saturday, September
15. Original Data Records (ODRs) from the first 2.4 orbits were
delivered to JPL by midnight (September 15), and three radar images
were completed by Sunday evening. These images were distributed as
part of the start-of-mapping press release on September 17.
During the past week, seven temporary Full-Resolution Basic Image
Data Records (F-BIDRs) and 24 final F-BIDRs were produced using ODRs
delivered to JPL on the evening of September 21. This enabled
production of the first large-scale (24-orbit) mosaicked image. This
image was featured at the press conference held on September 25.
The Deep Space Network (DSN) Operations Team, the Data Management
& Archive Team (DMAT), and the Operations Planning & Control Team
(OPCT) have completed the data collection and production of the final
Experiment Data Records (EDRs) for orbits 376 through 401 (orbits
since Venus Orbit Insertion (VOI)) on schedule. In addition, these
teams completed the quick-response data return and processing for the
initial production of images from orbits 376 and 377.
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
From: 17001_1511@uwovax.uwo.ca
Newsgroups: sci.astro
Subject: Re: Magellan articles
Date: 1 Oct 90 18:13:29 GMT
The various articles about the early Magellan images did contain a
few misleading statements. The particular points queried by S. Schaper
(thin plastic crust, deepest impact crater in the solar system) should
have read as follows:
The crater was Collette Patera, a large volcanic caldera, NOT an
impact crater as repeatedly stated in the press. Collette was seen
very well by the Veneras and is unquestionably a caldera. The 2 or 3
km depth is far from being the deepest in the solar system, so either
we were given a very wrong number or somebody just got carried away.
There are craters 10 km deep on the Moon, Amalthea, Mimas and
elsewhere. The thin plastic crust is only thin and plastic in a
relative sense. It can support over 10 km of topography at Maxwell
Montes and troughs such as Dali Chasma several km deep.
Phil Stooke
Dept. of Geography,
University of Western Ontario,
London, Ontario, Canada N6A 5C2
|
| 456.165 | MAGELLAN Update - October 2 | ADVAX::KLAES | All the Universe, or nothing! | Wed Oct 03 1990 17:40 | 42 |
| From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 10/02/90
Date: 2 Oct 90 22:48:10 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
October 2, 1990
The Magellan spacecraft has acquired about 125 orbits of Venus
radar mapping data since mapping officially began on Sept. 15. When
mosaicked, the wedge-shaped area of imagery would cover on Earth a
stretch across the southern United States from Los Angeles to nearly
the coast of South Carolina, and from the North Pole to almost the
South Pole. The DSN (Deep Space Network) acquisition of the radar
data has averaged 98.9 percent.
A spacecraft anomaly investigation review was held in Denver
on September 27. Review board members said additional heartbeat
modifications are being studied to facilitate mapping through an AACS
(Attitude and Articulation Control Subsystem) glitch. These are
planned to be implemented in December. By the end of January 1991, the
flight controllers will try to implement an interim fix to the AACS
B-side memory to make it usable.
The long term memory-B fix is targeted to be completed as early
as June 1 of next year, but it could take as long as to the end of the
year. The long-term fix also will incorporate software modifications
to guard against computer glitches.
Most investigations as to the primary cause of the August 16 loss
of signal are being closed out. The actual cause has not been found,
but several candidates have been eliminated.
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
|
| 456.166 | MAGELLAN Update - October 3 | ADVAX::KLAES | All the Universe, or nothing! | Thu Oct 04 1990 13:30 | 34 |
| Date: 3 Oct 90 23:49:15 GMT
From: (Ron Baalke)
Subject: Magellan Update - 10/03/90
MAGELLAN SPECIAL REPORT
October 3, 1990
A loss of power at the Deep Space Network (DSN) station near
Madrid, Spain, resulted in loss of radar data reception of one-half of
orbit 490 and all of the mapping data from orbit 491.
A bad star calibration on orbit 493 caused a shift in the HGA
(High Gain Antenna) pointing of approximately half a degree which
severely degraded the downlink during playback of the second half of
orbit 493 and the first half of orbit 494.
Additionally, radar data was taken on orbit 494 with the HGA
mispointed by half a degree. Some or all of that data may be salvaged
by special processing.
Steps were being taken to limit the size of star calibration
updates to prevent bad updates from mispointing the antenna.
The orbits are counted from August 10 when Magellan went into
orbit around Venus. An orbit takes three hours and 15 minutes and
there are seven and a third orbits a day.
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
|
| 456.167 | MAGELLAN Updates - October 5 and 8 | ADVAX::KLAES | All the Universe, or nothing! | Mon Oct 08 1990 17:38 | 76 |
| From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 10/05/90
Date: 8 Oct 90 17:17:46 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
Magellan Status Report
October 5, 1990
The Magellan spacecraft has now completed 147 mapping orbits,
with good data from at least 143 orbits. The spacecraft and radar
telemetry continue to be nominal. The solar array output of the
spacecraft is at 1240 watts. Seven star calibrations, two
desaturations and fourteen periods of DSN (Deep Space Network)
coverage were successful in the past 24 hours. One star crossing was
rejected by the foreground filter because it magnitude was greater
than expected. This will be corrected along with updates of the radar
parameters.
The SAR (Synthetic Aperture Radar) Data Processing System has
been going through engineering tests and upgrades the past week in
preparation for normal operations on October 8. Three new F-BIDRs
(Full-Resolution Basic Image Data Record) were produced to verify the
system. The Image Data Processing Team completed production of 29
full-resolution mosaics covering the full length of the first 24
mapping orbits and 25 special image products in the past week.
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 10/08/90
Date: 8 Oct 90 17:58:09 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
Magellan Status Report
October 8, 1990
The Magellan spacecraft has now completed 170 mapping orbits of
Venus, with good radar data from at least 165 orbits. Last Saturday,
October 6, Gyroscope B-2 again exhibited erratic behavior with
increases in temperature and motor current. The gyroscope was
initially marked as unusable and then turned off to allow it to cool
to 25 degress C. It was turned on again, but quickly heated to over
60 degrees C, so it was turned off and left off. This gyro was in
backup status, so the spacecraft's attitude continued to be controlled
by the other gyroscopes.
The high power transmitter, TWTB, experienced a spurious shutdown
on October 7. On board fault protections switched to TWTA, but 37
minutes of radar playback data was lost due to the delay in
reacquiring the signal after reconfiguring for the change in signal
polarization. Magellan has experienced prior spurious shutdowns in
the TWTA, 4 in pre-launch tests and 5 in flight. The investigation is
being reopened of the TWTA shutdown model, and contigency plans are
being reviewed for quick responses to future occurrences.
All star calibrations since October 5 have been successful except
for orbit 544 (orbit since Venus Orbit Insertion) this morning, when one
star was missed. All desaturations of the reaction wheels were nominal.
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
|
| 456.168 | Future plans (cycles) for MAGELLAN | ADVAX::KLAES | All the Universe, or nothing! | Tue Oct 09 1990 14:58 | 62 |
| From: henry@zoo.toronto.edu (Henry Spencer)
Newsgroups: sci.space,sci.space.shuttle
Subject: space news from Aug 20 AW&ST
Date: 9 Oct 90 06:27:10 GMT
Organization: U of Toronto Zoology
Magellan enters Venus orbit Aug 10, checkout underway. [This was
before Magellan acted up.] Discussion of plans for Magellan after its
243-day [1 Venus year] primary mission ends. Objectives for the
second and third "cycles" are fairly well-established: the second
will fill the various gaps in the first's coverage [caused by, e.g.,
the Sun getting between Earth and Venus] and will start mapping of the
south polar region (not covered at all by the first cycle), while the
third will fill remaining gaps, improve south polar coverage, and
study the detailed structure of Venus's gravitational field by
transmitting a beacon signal to the Deep Space Network for precision
tracking on some orbits. There are a number of ideas for later cycles:
- Remapping interesting areas at a consistent side-look angle, to give
similar features similar appearance; the initial mapping campaign
varies the side-look angle continuously due to varying orbital
altitude during each pass.
- Remapping interesting areas while looking forward or aft along the
ground track, to give better contrast on linear features that
are perpendicular to the track.
- Stereo imaging by mapping interesting areas from more than one angle.
- Remapping possibly-active areas to look for changes.
- Rolling the spacecraft around its antenna axis to view the planet at
different polarization angles.
- Viewing the same area from slightly different orbits to set up a
"baseline" for interferometry, which might make it possible to
compare phase shifts in the returned signals and do altitude
measurement to millimeter resolution. This might suffice to
detect tectonic movements.
- Aerobraking [!] to bring Magellan down to a 300km circular orbit,
giving higher mapping resolution and better gravity measurements.
This will be a dicey procedure because Magellan was not designed
for it, and there are also possible thermal problems with the
lower orbit (since there is a lot of reflected sunlight from
Venus's clouds). Aerobraking will not be tried until everything
else of major interest has been done, meaning the fourth or
fifth cycle at the earliest.
Magellan is experiencing various minor problems [some of which may
have contributed to the later troubles] but is basically healthy. The
solid injection motor behaved perfectly, and fuel consumption for
attitude control during the injection burn was lower than expected.
Magellan's fuel supply should suffice for 10 years or more [well, this
will be revised downward a bit because of some of the gymnastics
during the troubles]. The Pioneer Venus orbiter tried to photograph
the injection burn using its ultraviolet polarimeter, but the rocket
plume wasn't bright enough to be visible.
Henry Spencer at U of Toronto Zoology
henry@zoo.toronto.edu utzoo!henry
|
| 456.169 | MAGELLAN Update - October 9 | ADVAX::KLAES | All the Universe, or nothing! | Tue Oct 09 1990 20:00 | 40 |
| From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 10/09/90
Date: 9 Oct 90 18:09:26 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
Magellan Status Report
October 9, 1990
The Magellan spacecraft has now completed 177 mapping orbits of
Venus, with good radar data recieved from at least 173 orbits.
Spacecraft systems are performing nominally. Gyroscope B-2 remains
off, and TWTA-A is being used for high-rate telemetry.
Six of the seven star calibrations during the past 24 hours were
successful with nominal attitude updates. The last star calibration
failed because the star was rejected due to magnitude. The two
desaturations were nominal. During the past 24 hours, commands were
sent to readout the CDS (Command Data System) fault protection history
buffer. This confirmed that thw swap of TWTAs on October 7 occurred
just as the exciter was turned on to begin the first playback. Today,
the command sequence for mapping load 283 will be uplinked.
Intensive radar system tests and processor modifications
performed during the past two weeks to test image swaths produced on
October 8, confirmed that the end-to-end test performance is nominal.
A review held yesterday determined that the radar system
implementation should be frozen and normal production of data products
initiated. The processing will begin with the reprocessing of data of
orbit 367 taken on September 15 do take advantage of recently
implemented SAR (Synthetic Aperture Radar) processing improvements.
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
|
| 456.170 | MAGELLAN Update - October 10 | ADVAX::KLAES | All the Universe, or nothing! | Thu Oct 11 1990 13:27 | 32 |
| From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 10/10/90
Date: 10 Oct 90 21:39:34 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
Magellan Status Report
October 10, 1990
The Magellan spacecraft has now completed 184 mapping orbits,
with good radar data received from at least 180 orbits. The seven
star calibrations and two desaturations of the reaction wheels in the
past 24 hours were successful with nominal attitude updates. Once
star calibration was partially successful.
The 8 day mapping upload M0283 was sent to the spacecraft
yesterday and is now executing. Engineering telemetry shows the radar
sensors continue to operate normally. A test image swath from orbit
534 was produced and confirmed satisfactory the end-to-end system
performance. Production of standard image products through the SAR
(Synthetic Aperture Radar) processor has started. Twelve image swaths
covering the reproccessing of orbits 376 through 387 were successfully
completed yesterday.
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
|
| 456.171 | Magellan and the Mariners | 15372::LEPAGE | Just treading water... | Thu Oct 11 1990 14:02 | 11 |
| Just as an aside, Magellan has now mapped 10% of Venus at high
resolution. This is comparable to the amount of Mars photographed at
high resolution by Mariner 6 and 7 in the late summer of 1969.
Considering what they saw of Mars (craters, chaotic terrain, and polar
deposits) and what they missed (dried river channels, volcanoes,
fault valleys, dune fields, etc.) Magellan is yet to have made its most
important and fascinating discoveries. I can't wait for the maps to
come out next year!
Drew
|
| 456.172 | MAGELLAN Update - October 11 | ADVAX::KLAES | All the Universe, or nothing! | Thu Oct 11 1990 19:46 | 46 |
| From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 10/11/90
Date: 11 Oct 90 17:55:25 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
Magellan Status Report
October 11, 1990
The Magellan spacecraft has now completed 192 mapping orbits of
Venus since the start of radar mapping operations on September 15.
Good radar data from at least 188 orbits has been received. Six of
the seven star calibrations in the past 24 hours were successful with
attitude updates of about 6/100 of a degree. The foreground filter
rejected one star on the unsuccessful star calibrations. The two
desaturations were nominal.
An increasing difference has been noted between the AACS
(Attitude and Articulation Control Subsystem) commanded position of
the solar panels and the position indicated by the potentiometers. If
allowed to continue, the Solar Array Drive Mechanism (SADM) control
loss fault protection could be triggered and a swap of the IODA
(Input-Output Drive Assembly) could be attempted. While the cause is
being investigated, a near-term fix of disabling the SADM control loss
fault protection was approved and commanded yesterday. The next step
is to readjust the software stops, reset the commanded position to
match the actual position, and renable the SADM control loss fault
protection. These corrections are expected to be completed by tomorrow.
Commands to update the RAM and ROM safing reference parameters
will be uploaded today. Radar engineering telemetry analysis and the
production of a test image swath from orbit 553 shows that the radar
sensor continue to operate normally.
Prodution of standard image products throught the SAR (Synthetic
Aperture Radar) processor continues. Eleven image swaths were
successfully completed yesterday.
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
|
| 456.173 | How close is P11 to Venus? | 19458::FISHER | I like my species the way it is" "A narrow view... | Fri Oct 12 1990 15:40 | 5 |
| Does anyone know how close Pioneer 11 is (in azimuth) to Venus? I'm wondering
how close they are to having the P11 spacecraft emergency use of the DSN preempt
receiving mapping data.
Burns
|
| 456.174 | | 4347::GRIFFIN | Dave Griffin | Fri Oct 12 1990 15:53 | 4 |
| Right now, I believe they are quite far apart - almost opposite. I'll
check over the weekend.
- dave
|
| 456.175 | | 4347::GRIFFIN | Dave Griffin | Sat Oct 13 1990 13:48 | 13 |
| Man - it has been cloudy out for awhile. My memory is shot.
They are currently about 45 degrees apart in azimuth (which works out
to 3 hours or so of absolute difference in tracking time: if you had to
stay on one target constantly during its pass overhead, the other one
would be available for 3 hours - what this translates for actual DSN
dish time, I don't know (slew rates, azimuth restrictions, or other
obstacles).
Oh yes, the angle size is decreasing, not increasing.
- dave
|
| 456.176 | | 19458::FISHER | I like my species the way it is" "A narrow view... | Mon Oct 15 1990 15:27 | 3 |
| Oh oh. At least they only have to listen to M. for < half the time.
Burns
|
| 456.177 | MAGELLAN Update - October 12 | ADVAX::KLAES | All the Universe, or nothing! | Mon Oct 15 1990 15:53 | 43 |
| From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 10/12/90
Date: 12 Oct 90 22:28:31 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
Magellan Status Report
October 12, 1990
At 10:06AM (PDT) this morning, the Magellan spacecraft started
its 200th mapping orbit. Since each orbit images about .05% of the
surface of Venus, and good radar data have been received from all but
4 orbits, the image data now covers about 11% of Venus. This is an
area covering a little over 40 degrees of longitude, and extending
from the North Pole to 65 degrees latitude.
All spacecraft systems are performing nominally. As we approach
solar conjunction, the S-band telecommunications are getting noisier.
The angle between the Sun, Earth and Magellan is now down to 5.2
degrees. The predicted limit of the S-band communications throught the
High Gain Antenna is 3.4 degrees, which will be reached in about a
week. Six of the seven star calibrations were successful, with
attitude updates averaging about .013 degrees. The foreground filter
again rejected a star in the unsuccessful star calibration. The two
desaturations of the reaction wheels were nominal.
Command to reconfigure the fault protection for solar conjunction
were uploaded yesterday. Additional commands to configure the attitude
control system to make the corrections to the solar array drive control
and update the radar mapping parameters will be upload today.
Radar systems continues to operate normally. Ten standard image
swaths were processed by the SAR (Synthetic Aperture Radar) processor
yesterday, bringing the total to 28 of reprocessed image swaths.
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
|
| 456.178 | MAGELLAN Update - October 15 | ADVAX::KLAES | All the Universe, or nothing! | Tue Oct 16 1990 13:29 | 33 |
| From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 10/15/90
Date: 16 Oct 90 03:56:26 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
Magellan Mission Status
October 15, 1990
At 9:46AM (PDT) this morning, the Magellan spacecraft started it
222nd mapping orbit. Good radar data has been received from all but 4
orbits. All spacecraft systems are performing nominally. 20 of 22
star calibrations performed over the weekend were successful, with
attitude updates ranging from 0.003 degrees to 0.29 degrees. One star
calibration was partially successful, and one failed due to a star
rejection. All desaturations were nominal.
The angle between the Sun, Earth and Magellan is down to 4.6
degrees. The predicted limit of the S-Band communications through the
High Gain Antenna is 3.4 degrees, which is expected to be reached on
October 20.
Commands to correct the solar array drive drift has been sent to
the spacecraft on October 12, but the drift problem has continued.
The cause is being investigated.
Radar systems continue to perform normally. 32 standard image
swaths were processed by the SAR (Synthetic Aperture Radar) processor,
bring to 60 the total number of image swaths processed. The double
exposure artifact in the orbit 391 image was found to be a minor
fixable flaw in the Experiment Data Record.
|
| 456.179 | MAGELLAN Update - October 16 | ADVAX::KLAES | All the Universe, or nothing! | Wed Oct 17 1990 14:42 | 52 |
| From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 10/16/90
Date: 16 Oct 90 18:44:38 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
Magellan Mission Status
October 16, 1990
All of Magellan's spacecraft systems are performing nominally as
Magellan starts its 229th orbit. The 7 star calibrations and the 2
desaturations of the reaction wheels of the past 24 hours were fully
successful with nominal attitude updates.
Yesterday the set points of the Battery 1 heaters were changed
to avoid both heaters coming on at the same time. Today the AACS
(Atitude and Articulation Control Subsystem) memory B will be filled
with an alternating bit pattern of 1's and 0's, and mapping sequence
M0290 will be uploaded.
The actual vs software commanded position of the solar array
drive has continued to diverge. This problem is believed to be a
related to the present Sun position causing the solar panel rotation
to be constrained by the physical stops. Because of cable wrap, the
solar panels cannot rotate 360 degrees and there is a tracking dead
band. The build up of error on each orbit between the command panel
position and the reported position may be due to non-linearities
building up in a potentiometer or an A-D converter. Moving the
software stops further away from the physical stops did not help.
Investigation is continuing. From Sun sensor data, we know the solar
panels are pointing to the Sun within 0.5 degrees, well within what is
required to charge the battery on each orbit. The fault protection
remains disabled and the solar panels are correctly pointed at the sun
reference to the sun sensors.
The angle between the Sun, Earth, and Magellan is now down to 4.4
degrees. The predicted limit of S-Band communications thru the High
Gain Antenna is 3.4 degrees, which we will reach on Saturday, 20 October.
The radar system continues to operate normally. Eleven new
standard image swaths, and one test swath were produced by the SAR
Processor yesterday. Six orbits of altimeter data were also processed
to test the data quality.
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
|
| 456.180 | MAGELLAN Update - October 17 | ADVAX::KLAES | All the Universe, or nothing! | Thu Oct 18 1990 17:11 | 46 |
| From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 10/17/90
Date: 17 Oct 90 22:03:26 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
Magellan Status Report
October 17, 1990
All spacecraft systems are performing nominally as Magellan
completes its 236th orbit. The 7 star calibrations and 2
desaturations of the past 24 hours were fully successful with nominal
attitude updates.
On two recent mapping passes, the two gyroscopes measuring the
spacecraft motion in the X axis gave differing values. These
miscompares were very small (0.02 radians), but are possibly related
to the solar array drive problem since its position errors are also in
the X axis. The cause is being investigated.
The upload yesterday, to fill parts of AACS (Attitude and
Articulation Control Subsystem) Memory B with alternating 1's and 0's,
inadvertently overwrote a buffer area which was not supposed to be
filled. This was corrected by uplinking a small memory patch. The
mapping sequence load and radar parameter files were uplinked without
problems.
The radar system continues to operate normally, but there has
been a significant increase in the telemetry channel bit errors. When
the data is lost, the computer fills the data record with zeros. On
orbit #598, for example, about one-fourth of the record was
zero-filled. This degradation of the SAR (Synthetic Aperture Radar)
data was expected as Magellan approaches Superior Conjunction.
Fourteen new standard image swaths were produced by the SAR
Processor yesterday. Five mosaicked images are being produced in the
Image Data Processing System to assess the radar system performance.
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
|
| 456.181 | MAGELLAN Update - October 18 | ADVAX::KLAES | All the Universe, or nothing! | Fri Oct 19 1990 17:10 | 47 |
| From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 10/18/90
Date: 18 Oct 90 23:00:11 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
October 18, 1990
The Magellan spacecraft has completed its 243rd orbit. The 7
star calibrations and 2 desaturations of the past 24 hours were
successful with nominal attitude updates.
All spacecraft systems are performing as expected while
controllers continue to analyze the relationship between the gyro
miscompares and the solar array drive position errors. It is possible
that the spacecraft has developed a slight "shimmy," but the
performance of the AACS (Attitude and Articulation Control Subsystem)
for pointing the radar antenna and keeping the solar panels oriented
to the Sun is nominal.
Final testing of the Superior Conjunction control sequences
produced some changes and the command upload is expected later today.
The radar system continues to operate normally, but there is
still some degradation which may be due to the approach to Superior
Conjunction. Several tests are planned and some temporary
modifications to data processing methods are being considered to
alleviate the adverse effects of the degraded data quality.
The primary SAR (Synthetic Aperture Radar) processor is out of
operation because of the failure yesterday of the input/output
computer. Initial diagnosis and repair was started yesterday, and
completion is expected late today.
The Image Data Processing System is processing 13 mosaics to be
used for scientific analysis and assess the radar system performance.
Test altimeter swaths for orbits 604 and 605 were successfully processed.
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
|
| 456.182 | Harold Masursky - August 24, 1990 | ADVAX::KLAES | All the Universe, or nothing! | Fri Oct 19 1990 18:45 | 15 |
| From: henry@zoo.toronto.edu (Henry Spencer)
Newsgroups: sci.space,sci.space.shuttle
Subject: Space news from September 3 AW&ST
Date: 19 Oct 90 03:14:16 GMT
Organization: U of Toronto Zoology
Harold Masursky, late of the U.S. Geological Survey, died Aug. 24.
He played a major role in choosing Apollo landing sites and scientific
objectives, headed the Mariner 9 mapping of Mars, helped select the
Viking landing sites, and was instrumental in getting Magellan funded.
He saw the first Magellan images a few days before his death.
Henry Spencer at U of Toronto Zoology
henry@zoo.toronto.edu utzoo!henry
|
| 456.183 | MAGELLAN Update - October 19 | ADVAX::KLAES | All the Universe, or nothing! | Fri Oct 19 1990 22:17 | 47 |
| From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 10/19/90
Date: 19 Oct 90 20:20:52 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
October 19, 1990
The Magellan spacecraft has now completed 250 mapping orbit. The
6 of the 8 STARCALS (star calibrations) and 2 DESATS (desaturations of
the reaction wheels) of the past 24 hours were successful with nominal
attitude updates. The two partially updates were caused by foreground
filter star rejections. All spacecraft systems are performing nominally.
Spacecraft engineers are now nearly certain that the gyro and
solar array position miscompares are caused by torsional oscillations
during each mapping pass. Deflections of the panel tip, where the sun
sensors are located, may be causing out-of-phase feedback in the
control loop. The oscillation is not serious enough to stop mapping,
but the system engineers are analyzing any possible impact on radar
performance and the likelihood of any long term fatigue effects.
The control sequences and fault protection parameters for the
period of Superior Conjunction were sent to the spacecraft yesterday
evening. The battery charging control was also changed now that the
spacecraft is out of Sun and Earth occultations.
The radar system continues to operate normally, but there is some
concern regarding the rate of zero-filled experiment data records.
For example, nearly 32% of the SAR (Synthetic Aperture Radar) bursts
on orbit #612 on Monday, October 15, were zero-filled. Several tests
are being performed on the received radar data and some temporary
modifications to data processing methods are being considered to
alleviate the adverse effects of the degraded data quality.
The primary SAR processor is back in operation and four new image
swaths were processed after the repair was completed yesterday evening.
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
|
| 456.184 | MAGELLAN takes a break from Venus mapping | ADVAX::KLAES | All the Universe, or nothing! | Fri Oct 19 1990 22:57 | 61 |
| From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan/Superior Conjunction (Forwarded)
Date: 19 Oct 90 22:19:59 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN TO TEMPORARILY HALT RADAR MAPPING OF VENUS
Nature will force Magellan Project flight controllers at NASA's
Jet Propulsion Laboratory, Pasadena, Calif., to temporarily halt radar
mapping of the surface of Venus in early November as Venus and Earth
near their maximum distance with the Sun in between.
The maximum distance between the planets, called superior
conjunction, occurs Nov. 1. The sun and Venus will be less than 1
degree apart. While Venus will not actually go behind the disc of the
sun, its nearness to the sun from Earth's point of view will cause
radio signals passing close to the Sun to degrade. JPL controllers
will still be able to communicate with Magellan periodically.
The time of superior conjunction was known and planned for early
in the Magellan mission planning.
Loss of the radio link at the S-band frequency, which transmits
telemetry to Earth stations through the high-gain antenna at 1200 bits
per second (bps), is predicted for Saturday when the angle between
Venus and the Sun, measured from Earth, narrows to 3.4 degrees.
But another Magellan radio frequency, called X-band, is degraded
less by the hot plasma around the Sun, and controllers said they
expect to be able to command the spacecraft by X-band each day through
more than a week of superior conjunction.
Use of X-band for the uplink started on Saturday, Oct. 13. Its
use both to and from the spacecraft is predicted to last until Oct.
27. The radio downlink rate is 268 kilobits per second (kbps).
Solar activity will determine how much the radio signals degrade
and how long mapping will be halted. Magellan project officials will
make go or no-go decisions on mapping on a day by day basis.
On Oct. 29, the spacecraft's computer automatically will halt
mapping for at least 9 days. The mapping could be halted for as long
as 2 weeks, however, depending on solar activity. If solar activity
is very heavy, fight controllers will switch earlier into the
spacecraft's computer sequence by ground command.
The first standard mapping sequence at 268 kbps, with telemetry
communication with Earth at 1200 bps, is scheduled to resume on Nov. 21.
Magellan is managed by JPL for the Office of Space Science and
Applications, Wash., D.C.
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
|
| 456.185 | MAGELLAN Update - October 22 | ADVAX::KLAES | All the Universe, or nothing! | Wed Oct 24 1990 20:23 | 32 |
| From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 10/22/90
Date: 23 Oct 90 03:20:56 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
Magellan Status Report
October 22, 1990
The Magellan spacecraft has now completed 273 mapping orbits
around Venus. The spacecraft and radar systems are performing
nominally, with the exception of a slight solar panel oscillation and
a suspect tape recorder. The cause og the zero-filled radar data
frames has been traced to track 2 of the spacecraft tape recorder A.
In the past two weeks, the rate of zero-filled frames has increased
from 0.1% to 30%. A single zero-filled frame causes the SAR
(Synthetic Aperture Radar) Processor to reject the frame.
Corrections include reprogramming the on-board mapping sequence
to avoid the faulty track on the tape recorder, and modifying ground
processing to allow partial frames of valid radar data.
Over the weekend, 53 orbits of SAR data were processed into image swaths.
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
|
| 456.186 | MAGELLAN Updates - October 23-24 | ADVAX::KLAES | All the Universe, or nothing! | Thu Oct 25 1990 13:46 | 77 |
| From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 10/23/90
Date: 24 Oct 90 16:00:00 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
October 23, 1990
The Magellan spacecraft has completed 280 mapping orbits of
Venus. The spacecraft and radar systems are performing well. The
slight solar panel oscillation is continuing and may be jiggling the
tape recorder but the condition does not pose a risk to the mission.
Star calibrations and momentum wheel desaturations were performed
without difficulty.
The Deep Space Network continues to receive S-band telemetry
through its 70 meter stations even though loss of the signal was
predicted for last Saturday because of the approach of Superior
Conjunction, with the sun nearly between the planets.
The weekly radar mapping command sequence and parameter files
were uploaded to carry the mission through superior conjunction.
A total of 165 mapping orbits have been processed. As of Monday,
October 22, more than 98 percent of the orbits mapped had been
successfully transmitted back to Earth. The Altimetry/Radiometry team
at MIT had processed 140 orbits of altimetry data.
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 10/24/90
Date: 24 Oct 90 18:55:45 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
October 24, 1990
The Magellan spacecraft continues to map Venus and has completed
its 287th mapping orbit. The 7 STARCALS (star calibrations) and 2
DESATS (desaturations of the reaction wheels) of the past 24 hours
were performed with nominal attitude updates. Two star rejections
were noted. A temperature sensor on the thermal blanket covering one
of the propulsion modules has failed.
The signal-to-noise ratio of the high rate telemetry at X-band is
3.5 db. The Sun-Earth-Magellan angle is now 2.5 degrees.
Mapping sequence M0297 was successfully sent to the spacecraft
and is presently executing. This sequence will automatically stop
mapping on Monday, October 29, if no further commands are uploaded.
The present mapping sequence switched from track 2 to track 4 of
tape recorder A. This appears to have greatly improved the rate of
zero-filled data frames. A software change in the SAR (Synthetic
Aperture Radar) data processor has been devised and tested which will
alleviate the problem of zero-filled frames.
Fifteen new image swaths were processed yesterday, bringing to
180 the number of full resolution image swaths.
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
|
| 456.187 | Magellan Update - 10/25/90 | 4347::GRIFFIN | Dave Griffin | Fri Oct 26 1990 12:44 | 35 |
| From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Date: 25 Oct 90 20:27:26 GMT
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
October 25, 1990
The Magellan spacecraft continues to map Venus and has
completed its 295th mapping orbit. The sun-Earth-Magellan angle
is now down to 2.3 degrees as Venus and Earth enter superior
conjunction.
At a meeting yesterdayit was decided to continue mapping
despite degraded communications caused by the sun's position
nearly between the two planets, difficulty in achieving the
required navigation precision and the spacecraft oscillations.
The oscillations are caused by a difference in commands to the
solar arrays by the sun sensors and the gyro.
Based on the better-than-expected performance of the S-band
communications during the approach to superior conjunction, the
project decided to switch to the 1200 bits per second engineering
telemetry one week earlier than had been planned when the planets
come out of superior conjunction in November.
Thirteen new image swaths were processed yesterday, bringing
to 193 the number of full resolution image swaths. The switch to
tape recorder track 4 from track 2 has greatly reduced the
problem of bad data frames.
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
|
| 456.188 | Magellan Update - 10/26/90 | 4347::GRIFFIN | Dave Griffin | Fri Oct 26 1990 18:40 | 44 |
| From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Date: 26 Oct 90 17:48:21 GMT
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
October 26, 1990
As the Magellan mission approaches Superior Conjunction, the project has
reviewed daily the increasing difficulties with telecommunication, navigation,
spacecraft performance, and radar data quality. The basic question was not
whether to suspend mapping, but when.
A decision was made to suspend mapping at the end of orbit #676, 6:33 AM
PDT on Friday, October 26. The spacecraft stopped its mapping maneuvers, and
will hold its position with the High Gain Antenna pointed to earth and the
solar panels directed toward the sun. The radar sensor remains in standby
mode.
Although the high rate X-band communications are still possible, they are
expected to deteriorate rapidly during the next 24 to 48 hours. The loss of
reliable communications also makes it difficult for the navigation team to
obtain the doppler data necessary for precise calculations of the radar track.
During Superior Conjunction the spacecraft engineers will have time to
analyze the solar panel oscillations and the possible tape recorder track
degradation. By putting the spacecraft in a quiescent state while a
a good engineering telemetry margin still exists, the expected damping of the
vibrations can be observed. It will also provide time for careful planning of
spacecraft command sequences when mapping is resumed.
The mapping will resume in early to mid-November. The portion of Venus
which is not imaged during this Superior Conjunction period will be covered
during the extended mission eight months from now.
Stephen Saunders, the Project scientist for Magellan, provided images and
text for a special pictorial on Magellan to be published in the November
issue of Scientific American. He also provided a special images for the covers
of the abstract volume of EOS.
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
|
| 456.189 | Magellan Articles | 4347::GRIFFIN | Dave Griffin | Fri Oct 26 1990 18:57 | 45 |
| From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Date: 25 Oct 90 20:54:04 GMT
Organization: Jet Propulsion Laboratory, Pasadena, CA.
Christian Science Monitor -- 10/25/90
"Venus Revealed Is An 'Amazing Place'"
By Robert Cowen
"The radar images of Venus sent by the Magellan spacecraft in the
last few weeks are 10 times sharper than any that scientists have
seen before."
The Monitor says that these images have already revealed an entirely
"new" Venus, one which scientists are calling "an amazing place"
with features not seen in other worlds in our solar system.
The paper says that the scientific analysis of Magellan's radar
pictures of Venus must account for the planet's tremendous
atmospheric pressure and high surface temperatures. In this
environment, the paper says, land features "relax away" in a
relatively short period of a few hundred million years. The science
team must learn to take this into account, the Monitor concludes.
--------------------
Associated Press -- 10/25/90
"Magellan-Venus"
By Lee Siegel
"Venus has 600-mile-wide circular bulges on its surface caused by
molten rock pressing up from inside the planet, the same kind of
forces that created Hawaii, a Magellan scientist says."
The wire service says that Ellen Stofan, a geologist who analyzes the
spacecraft's pictures of Venus at the Jet Propulsion Laboratory, says
the bulges are nearly a mile high. The report quotes Stofan as saying
"you have hot material that rises from deep within the interior of the
planet." This material, the report says, is causing bulges which look
like sets of concentric rings. The bulges, according to the wire
service, are called "coronas."
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
|
| 456.190 | Magellan Update - 10/29/90 | 4347::GRIFFIN | Dave Griffin | Mon Oct 29 1990 23:34 | 43 |
| From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Subject: Magellan Update - 10/29/90
Date: 29 Oct 90 17:42:24 GMT
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
October 29, 1990
Radar mapping was suspended on October 26, at 6:23 AM PDT, for Superior
Conjunction. This suspension will last for approximately 12 days until early
November, while Venus and the spacecraft pass behind the Sun as viewed from
Earth. Earliest mapping start-up date is November 7.
The spacecraft will keep its High Gain Antenna pointed directly toward
Earth throughout the Superior Conjunction period, so as to permit the
transmission of engineering telemetry at 40 bps and the reception of commands
from Earth. It will turn away from Earth only to perform star scan maneuvers
in order to update its inertial reference sensors. This attitude will shade
the spacecraft's electronics from the Sun and keep the temperature cool.
Telemetry and commanding should be possible throughout Superior Conjunction.
During the Superior Conjunction period, modifications and testing to the
spacecraft software will be developed to prevent the oscillations which have
been observed in the Solar Arrays. Although this oscillation does not present
an immediate threat to the spacecraft, stopping it will prevent any long term
fatigue of the Solar Array mechanism.
Since September 15, Magellan has performed 40 days of radar mapping,
producing 301 image strips covering 60 degrees of longitude around Venus. The
mission has thus already covered roughly 1/6 of the planet.
A status review of Attitude Control software fixes will be held in Denver
on October 31. The next press conference to be held on November 16 at JPL
will focus on images of Ishtar Terra. A mission planning review for the 2nd
cycle, the first extended mission cycle of 243 days starting on April 29,
1991, will be held on November 29.
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
|
| 456.191 | MAGELLAN Update - November 5 | ADVAX::KLAES | All the Universe, or nothing! | Mon Nov 05 1990 19:26 | 39 |
| From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 11/05/90
Date: 5 Nov 90 19:06:34 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
November 5, 1990
The Magellan spacecraft continues quietly in its Superior
Conjunction phase. Engineering telemetry at both S and X-band has
been maintained and all systems are nominal. The three STARCALS (star
calibrations) and six DESATS (desaturations of the reaction wheels)
during the weekend were performed successfully.
No spacecraft command activity is planned for today. However,
the first Go/No Go meeting to decide on the resumption of mapping is
scheduled for 1 PM PST today. Barring any unexpected problems, the
command sequence to begin mapping will be sent to the spacecraft
tomorrow and will start execution on Wednesday morning, November 7.
The radar sensor remains in good health and in standby condition.
Four new full resolution image strips were processed on November 2,
but the quality of portions corresponding to the spacecraft tape
recorder track A2 is severely degraded.
The Image Data Processing Team produced check prints and photo
enlargements of the thirteen full res mosaics, called engineering
F-MIDRs. Digital processing of seven additional F-MIDRs requested by
the science team was also completed.
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
|
| 456.192 | PIONEER VENUS/MAGELLAN Update - November 2 | ADVAX::KLAES | All the Universe, or nothing! | Tue Nov 06 1990 14:50 | 32 |
| From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Pioneer Venus Update - 11/02/90
Date: 5 Nov 90 23:40:48 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
Pioneer Venus Status Report
November 2, 1990
The first simultaneous track of the Pioneer Venus spacecraft with
the Magellan spacecraft was supported on October 25 using the 34 meter
and 70 meter antennas in Goldstone, California. Telemetry data was
received; however, there was some difficulty with commanding due to
Venus' proximity to the Sun. At the present time, 100 kw or more is
required to successfully command the Pioneer Venus spacecraft. This
situation will continue to improve after the minimum SEP angle (0.87
degrees) is reached on November 2.
The Goldstone 34 meter antennas failed to acquire receiver lock
on October 30. 70 meter support in Australia was taken from Pioneer
11 on October 31 so that the high power transmitter could be used to
uplink to the spacecraft at 100 kw and avoid an automatic receiver
switch from occurring.
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
|
| 456.193 | MAGELLAN Update - November 6 | ADVAX::KLAES | All the Universe, or nothing! | Wed Nov 07 1990 14:49 | 40 |
| From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 11/06/90
Date: 6 Nov 90 22:50:42 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
November 6, 1990
The Magellan spacecraft is in good health as it exits the
Superior Conjunction phase. At the Go/No Go meeting yesterday it was
decided to resume mapping at the earliest opportunity. The command
sequence will be sent to the spacecraft late today and will start
execution at 4:20 AM (PST) tomorrow morning with orbit #765.
Several attempts were required this morning to upload a series of
commands which reconfigure the spacecraft for mapping. This is
believed to be a Superior Conjunction effect because the
Sun-Earth-Magellan angle is only 1.4 degrees.
Good downlink communications have been maintained partially
because the DSN (Deep Space Network) can broaden the bandwidth of the
receiver, but the spacecraft does not have similar adjustments to its
command receiver to improve the uplink. The radar sensor remains in
excellent condition and ready for mapping.
Nine standard and seven special image swaths were produced by the
SAR (Synthetic Aperture Radar) Data Processor. The special image
swaths involved reprocessing of the polar area from early orbits to
obtain the improved quality made possible by the recent change to the
topographic model used by the processor.
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
|
| 456.194 | MAGELLAN Updates - November 7-8 | ADVAX::KLAES | All the Universe, or nothing! | Fri Nov 09 1990 17:13 | 131 |
| From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 11/07/90
Date: 7 Nov 90 19:21:15 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
November 7, 1990
The Magellan spacecraft is in good health, but is still in its
Superior Conjunction mode. After several unsuccessful attempts to
upload the series of commands to re-configure the spacecraft, a
decision was made to postpone the restart of mapping. Command uploads
were attempted at both X and S-band frequencies.
Due to the difficulty with getting the spacecraft to accept the
relatively simple configuration commands, it was considered very
unlikely that uploading the longer mapping sequences and parameter
files would be successful.
The communications problems had been predicted by the DSN (Deep
Space Network) when the Sun-Earth-Magellan angle was less than 2.5
degrees. During the approach to Superior Conjunction, no commanding
was attempted inside of 2.0 degrees, so it is not surprising that
there are problems at yesterday's 1.4 degrees.
The present plan is to upload the mapping sequence on Friday,
November 9, when the Sun-Earth-Magellan angle is 2.0 degrees.
Execution of the sequence will begin with orbit #787 at 4:07 AM PST on
Saturday, November 10. If mapping resumes as now scheduled, the
"Superior Conjunction Gap" will include 110 orbits or about 22 degrees
of longitude. This area will be mapped between June 26 and July 11,
1991 when Magellan again passes over.
The SAR (Synthetic Aperture Radar) Data Processor produced 8
standard and one special image swaths yesterday.
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan article
Date: 8 Nov 90 18:24:35 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
Associated Press -- 11/8/90
"Magellan"
By Lee Siegel
"The Magellan spacecraft has found evidence that ocean-sized floods of
molten rock once inundated more than half the surface of Venus."
AP reports that NASA scientists do not yet know if there was one great
outpouring of lava from cracks in Venus or a series of smaller flows,
each hundreds of thousands of square miles, that engulfed parts of the
planet at different times.
The wire service says that geologist and Magellan project scientist
Steve Saunders believes that lava gushed out of cracks called vents in
a global set of eruptions that happened all at once, perhaps 400
million years ago. Saunders is quoted by the AP as saying "there's no
question that the vast majority of the surface of Venus has been
formed by lava flows and volcanic activity. But the question is, did
it all happen catastrophically?"
According to the story, the lava covers more than sixty percent of the
surface of Venus and accounts for the lack of craters resulting from
meteoritic impacts, as the lava flows would eradicate any evidence of
impact cratering.
The story says that Venus's widespread lava flooding was similar to,
but much larger than, the vast deposits of basalt in India's Deccan
Traps and the Pacific Northwest's Columbia River basin.
According to the report, the Indian Deccan Traps occurred when the
crust split open as the Indian continental plate drifted away from
Africa about 66 million years ago. The Columbia River basin deposits
occurred, again according to the AP, when massive eruptions rent much
of the Pacific Northwest east of the Cascade Range about 20 million
years.
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 11/08/90
Date: 8 Nov 90 19:45:47 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
November 8, 1990
The Magellan spacecraft is in good health, in its Superior
Conjunction mode. The daily STARCALS (star calibrations) and twice
daily DESATS (desaturations) have been successful.
Yesterday's commands to re-configure the spacecraft were
successfully uploaded, including setting the command loss timer to 9
days and disabling the S-band RF loss monitor.
Today the spacecraft controllers plan to play back track 4 of the
tape recorder and uplink other configuration commands in preparation
for Friday's upload of the mapping sequence. Execution of the sequence
will begin with orbit #787 at 4:07 AM PST on Saturday, November 10.
If mapping resumes as now scheduled, the "Superior Conjunction
Gap" will include 110 orbits or about 22 degrees of longitude. This
area will be mapped between June 26 and 11 July 11, 1991, when
Magellan again passes over.
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
|
| 456.195 | MAGELLAN Update - November 9 | ADVAX::KLAES | All the Universe, or nothing! | Mon Nov 12 1990 19:40 | 33 |
| From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 11/09/90
Date: 10 Nov 90 05:35:40 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
November 9, 1990
The Magellan spacecraft is performing nominally. The daily
STARCALS (star calibrations) and twice daily DESATS (desaturations)
continue to go well. Yesterday, track 4 of the Tape Recorder A was
successfully played back, and track 1 of the Tape Recorder B was
positioned for playback today. It contains the results of the STARCALS
performed during Superior Conjunction.
Several of the command uplinks were rejected due to sun effects,
but mapping restart remains on schedule. The decision for GO on the
mapping restart will be made today, and execution of the sequence will
be made on orbit 787 at 4:07 AM (PST) tomorrow on November 10.
The radar sensor remains in standby mode. Eleven new standard
image swaths were produced, but one of these products is being held
for a quality check.
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
|
| 456.196 | MAGELLAN Update - November 12 | ADVAX::KLAES | All the Universe, or nothing! | Mon Nov 12 1990 21:19 | 29 |
| From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 11/12/90
Date: 12 Nov 90 22:05:02 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
November 12, 1990
The Magellan spacecraft performance is nominal. The spacecraft
successfully accepted commands on Friday, November 9, resuming mapping
on orbit 787 at 4:07 am PST on Saturday, November 10. One STARCAL
(star calibration) occurs every orbit and 1 DESAT (desaturation of the
reaction wheels) every 4th orbit. 16 STARCALS and 4 DESATS have been
done since mapping resumed.
A sequence patch to disable solar array control during mapping
has prevented the spacecraft vibration from recurring. Track 1 of
tape recorder B was successfully played back on November 9. It contains
the results of STARCALS performed during Superior Conjunction.
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
|
| 456.197 | MAGELLAN Update - November 13 | ADVAX::KLAES | All the Universe, or nothing! | Tue Nov 13 1990 18:42 | 31 |
| From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 11/13/90
Date: 13 Nov 90 19:12:06 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
November 13, 1990
The Magellan spacecraft is now in its 17th mapping orbit since
radar mapping was resumed on the morning of November 10. All systems
are nominal and six of the seven STARCALS (star calibrations) in the
past 24 hours were fully successful.
Late today, a software patch to control the solar panel positions
with ephemeris tables will be sent to the spacecraft.
Analysis of radar data from tape recorder track A4 indicates that
it is about the same as before Superior Conjunction. That is, it does
not show the progressive deterioration that was seen on track 2, but
the rate of errors was not improved by eliminating the solar panel
vibrations.
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
|
| 456.198 | MAGELLAN Update - November 14 | ADVAX::KLAES | All the Universe, or nothing! | Thu Nov 15 1990 12:53 | 77 |
| From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 11/14/90
Date: 14 Nov 90 22:04:42 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
November 14, 1990
The Magellan spacecraft is now in its 31st mapping orbit since
radar mapping was resumed last Saturday, November 10. All systems are
nominal and six of the seven star calibrations in the past 24 hours
were fully successful.
Yesterday, the software patch to control the solar panel
positions with ephemeris tables was sent to the spacecraft.
Further analysis of radar data from tape recorder track A4 now
indicates that it does show the progressive degradation that was seen
on track 2. Although the error rate causes only moderate image
degradation, data management stategies to avoid these tracks are now
being studied.
Other analyses disclosed that the SAR (Synthetic Aperture Radar)
sampling window is not being accurately centered on the part of the
signal echo corresponding the the center of the SAR antenna beam.
This problem may be caused by an error in the estimated time of
periapsis or some other timing error. The problem may cause minor to
moderate image quality degradation, depending on whether the SAR
processor can compensate for the effective pointing error. The
problem is being investigated.
Two bursts of radar data in each of several consecutive orbits
have exhibited abnormal amplitude characteristics. This problem is
considered minor because it affects less than 0.1% of the data from
each orbit. This anomaly was confirmed by the occurance of two bright
patches in the test image swaths of orbit #796.
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan News Conference
Date: 14 Nov 90 22:02:07 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN NEWS CONFERENCE SCHEDULED
There will be a Magellan mission news conference at the Jet
Propulsion Laboratory's von Karman Auditorium at 1 p.m. EST, Friday,
Nov. 16. Speakers will discuss spacecraft status and recent science
results.
Speakers will include Magellan Project Manager Anthony Spear,
Project Scientist Dr. Stephen Saunders, Drs. Gordon Pettengill and
Sean Solomon of the Massachusetts Institute of Technology and Dr. Ray
Arvidson of Washington University, St. Louis. New radar images of the
Venus surface and a new 3-D video will be shown.
The news conference will be carried on NASA Select TV, Satcom
F2R, transponder 13, at 72 degrees west longitude, 3960.0 MHz, audio
6.8 MHz, with two-way question and answer capability.
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
|
| 456.199 | MAGELLAN Update - November 15 | ADVAX::KLAES | All the Universe, or nothing! | Fri Nov 16 1990 16:16 | 77 |
| From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 11/15/90
Date: 15 Nov 90 23:55:31 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
November 15, 1990
The Magellan project experienced the third loss-of-signal
incident shortly after 9:00 am PST today, when the Magellan spacecraft
failed to return to Earth communications after the mapping pass of
orbit #825. The S-band signal was reacquired about 40 minutes later,
and engineering telemetry indicated that the control system had
detected a "heartbeat loss" similar to the incidents in August.
The spacecraft had switched some components, such as the gyros
designated as primary, but was continuing to execute its command sequence.
Telemetry signal levels indicate that the high gain antenna is
off Earth point by 1-1/2 to 2 degrees. This is beyond the limits of
the high rate X-band communications, so we are not able to receive the
radar data being played back by the spacecraft.
At 9:58 am PST the spacecraft performed a star calibration, but
the update would have been rejected because the 1-1/2 degree
correction is greater that the bounds set within the attitude control
system. The innovation bound will be set higher in conjunction with a
ground command to update the spacecraft's onboard quaternion, so that
the next STARCAL (star calibration) will correct the spacecraft
attitude and the exact pointing of the high gain antenna.
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
From: clarinews@clarinet.com
Newsgroups: clari.tw.space,clari.news.gov.usa
Subject: Magellan signal lost, regained
Date: 16 Nov 90 03:51:38 GMT
PASADENA, Calif. (UPI) -- The Magellan spacecraft, on a
mission to map the planet Venus, experienced a 40-minute signal loss
Thursday, its third since it went into orbit around the planet in August.
The Jet Propulsion Laboratory at Caltech in Pasadena said the
craft's signal was lost for 40 minutes beginning shortly after 9 a.m.,
as Magellan was on its 825th orbit around Venus.
One of the spacecraft's two radio signals was restored about
9:40 a.m., but the second high-gain antenna remained pointed away from
Earth, officials said.
The spacecraft's altitude was corrected to restore the
high-gain antenna and resumed at 6 p.m.
JPL officials lost the spacecraft's radio signal for about 11
hours on Aug. 16 and for an additional 17 hours Aug. 21.
Officials said the problems leading to the loss of
communication Thursday were similar to the August incidents, but
software improvements prevented extended communications disruptions.
The $287 million radar mapping probe was launched from the
shuttle Atlantis May 4, 1989, for a planned mission of at least 243
days. The goal is to map at least 90 percent of the surface of Venus
by using a high-tech cloud-piercing radar system that can detect
surface features as small as 400 feet.
Computer processing on Earth converts the radar date into
photo-like black-and-white images.
|
| 456.200 | MAGELLAN Update - November 16; news conference | ADVAX::KLAES | All the Universe, or nothing! | Mon Nov 19 1990 16:55 | 139 |
| From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 11/16/90
Date: 16 Nov 90 23:33:53 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
November 16, 1990
The Magellan spacecraft is now performing nominally in mapping
mode after experiencing its third loss-of-signal incident yesterday
morning. It has just completed its 344th mapping orbit.
Shortly after 9:00 AM PST yesterday, the spacecraft failed to
return to Earth communications after the mapping pass of orbit #825.
The S-band signal was reacquired about 40 minutes later, and signal
level indicated that the high gain antenna was off Earth point by
1-1/2 to 2 degrees. The X-band signal required for radar data
playback could not be acquired.
Engineering telemetry indicated that the control system had
detected a "heartbeat loss" similar to the incidents in August. The
spacecraft had switched some components, such as the gyros and the
Input/Output unit, but was continuing to execute its command sequence.
The next three star calibrations were rejected because the one to
three degree corrections would be greater than the limit set within
the attitude control system.
At 3:19 PM PST, attitude updates were sent to the spacecraft to
correct the antenna pointing and mapping was resumed at 6:46 PM. The
quick recovery from this loss of signal incident demonstrates the
contingency plans which were developed as a result of the earlier
incidents. In August, mapping was delayed for at least 15 days. Today,
mapping was resumed after 9.75 hours, with a loss of only 3 orbits.
Stephen Saunders, Magellan's project scientist, provided images
and text for a special pictorial on Magellan to be published in the
January Astronomy Magazine.
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
From: clarinews@clarinet.com (WILLIAM HARWOOD, UPI Science Writer)
Newsgroups: clari.tw.space
Subject: New Magellan photos of Venus released
Date: 16 Nov 90 23:02:58 GMT
Scientists Friday unveiled stunning new images of Venus taken
by the Magellan radar mapping probe, including a breathtaking computer
movie simulating a low-altitude flight around the tortured slopes of a
towering 38,000-foot mountain.
Magellan project manager Anthony Spear said the solar-powered
probe has mapped 18 percent of Venus's hidden surface so far, despite
a subtle glitch that has knocked the craft out of contact with Earth
three times since it slipped into orbit around the cloudy planet Aug. 10.
The most recent incident occurred Thursday when Magellan lost
contact for 40 minutes. Subsequent work to re-align Magellan's dish
antenna with Earth resulted in the loss of three orbits of mapping
data, but Spear said engineers were pleased with how fast they were
able to get the craft back into action.
``We've had our share of problems, but they've all been minor
problems,'' Spear said at a news conference at the Jet Propulsion
Laboratory in Pasadena, Calif. ``I think...our ability to work
around these problems is a major testimony to the resiliency and
robustness of this spacecraft's design.''
Magellan, built by Martin Marietta Astronautics Group of
Denver, dropped into orbit around Venus 15 months after launch from
the Space Shuttle Atlantis on May 4, 1989.
The 2 1/2-ton solar-powered satellite was designed to ``see''
through the clouds that perpetually blanket Venus by bouncing radar
beams off the planet's surface.
Extensive computer processing on Earth can convert such radar
data into photo-like images showing surface features as small as a
football field, some 10 times better than the best previous effort.
Magellan began mapping the surface of Venus on Aug. 16. But
after one and a half orbits, the spacecraft suddenly went into a
computer-induced state of hibernation and aimed its main antenna away
from Earth.
Contact was restored the next day, but it was lost again the
following week. Emergency commands radioed to Magellan ``in the
blind'' caused to spacecraft to search for Earth and communications
ultimately were restored.
Magellan's electronic brain was subsequently reprogrammed to
make it easier to restore contact whenever the glitch might occur in the
future by preventing it from going into such computer-induced hibernation.
``This was a good demonstration of our ability now to handle
this signal loss problem,'' Spear said of the most recent incident. But
he added: ``We've got to expect it's going to happen again periodically.''
Magellan was built to map at least 70 percent of the surface
of Venus during a 243-day mission. But the spacecraft is expected to
continue working well beyond that point, allowing scientists to fill
in the blanks caused by the signal drop outs and to increase coverage
to more than 90 percent of the planet. The ``extended mission'' starts
in May.
At the news conference Friday, scientists released a variety
of spectacular, high-resolution radar images of the planet's tortured
surface, including unprecedented shots of Ishtar Terra, an elevated
plateau about the size of Australia that rises nearly 10,000 feet
above the surrounding countryside.
On the eastern side of the plateau is a giant mountain called
Maxwell Montes that rises some 38,000 feet above the average surface
of the planet -- more than a mile taller than Mt. Everest.
Magellan project officials released a stunning
computer-generated movie based on data from Magellan and previous
spacecraft that simulated a low-altitude flight over Ishtar Terra and
around Maxwell Montes that provided a breathtaking view of the region.
Based on Magellan temperature measurements of the surface, the
flanks of the mountain appear to be covered with a ``mystery'' material,
possibly pyrite, or ``fool's gold.''
Other images included stunning shots of lava flows and impact
craters that appear to be associated with giant horseshoe-shaped
markings stretching thousands of miles that may have been formed in
part by the atmospheric shock waves produced by incoming meteorites.
``The project health is very good,'' Spear said. ``The next
line of business is to get ready for our extended mission, which
starts on May 1.''
|
| 456.201 | MAGELLAN Update - November 19 | ADVAX::KLAES | All the Universe, or nothing! | Tue Nov 20 1990 17:13 | 82 |
| From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 11/19/90
Date: 19 Nov 90 20:43:57 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
November 19, 1990
The Magellan spacecraft is performing nominally in mapping mode,
and has just completed its 369th mapping orbit. Image data from 361.2
orbits has been successfully transmitted to Earth. All DESATS (desatu-
rations) over the weekend were nominal, and 21 out of 22 STARCALS (star
calibrations) were successful with small attitude updates.
Since November 16, the limit value on attitude updates was reset
to .07 degree, and the heartbeat loss table was reset to its
configuration prior to the recent loss of signal incident.
The radar system is performing nominally. Later today, an
evaluation of the playback performance, using the new data management
strategy which avoids tracks A2 and A4, will be completed.
The SAR (Synthetic Aperture Radar) Data Processing Team
reprocessed the SAR data from orbits 419, 447, and 547 to achieve
improved quality. The normal flow of new image swaths is not
scheduled to resume until November 26.
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update #2 - 11/19/90
Date: 19 Nov 90 21:21:04 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
November 19, 1990
The Magellan spacecraft has sent back images of some unusual
features on the surface of Venus. The most intriguing image is one
showing what looks like seven pancakes, that was apparently formed by
a series of oozing volcanic eruptions. Each "pancake" volcano
measures about 15 miles in diameter and are about 2500 feet tall, and
are near perfect circular symmetry. The volcanoes are clustered near
each into three groups, with two pair of volanoes overlapping each
other, and the third group having three overlapping volcanoes.
The image of Maxwell Montes, the highest mountain on Venus at
about 7 miles, has what appears to be snow covering it sides.
However, with a surface temperature of 700 degrees Fahrenheit, it is
very unlikely that snow or ice would form on Venus. Clues of the
composition of the surface can be obtained from the radar emission,
and the the radar emission from the areas covered by the "snow" has
indicated that the snow may be iron pyrite, also known as fool's gold.
Images of horseshoe shaped formations were also sent back by
Magellan, which are considered to be unique in the solar system. It
has been speculated that these horseshoe shapes were formed by
material being deposited from vaporized ejecta from incoming
meteorites, which were caught in the planetary winds high up in the
atmosphere and later deposited on the surface.
Enormous riverbeds were also seen winding their way through
hills, resembling those seen on Earth. However, unlike the rivers on
Earth, it is thought that the rivers on Venus were rivers of molten lava
that burned its way into the surface as it flowed for hundreds of miles.
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
|
| 456.202 | MAGELLAN and PIONEER VENUS Update - November 16/20 | ADVAX::KLAES | All the Universe, or nothing! | Wed Nov 21 1990 19:28 | 57 |
| From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 11/20/90
Date: 20 Nov 90 21:51:52 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
November 20, 1990
The Magellan spacecraft is performing nominally in mapping mode,
and has just completed its 376th mapping orbit. The two DESATS
(desaturations of the reaction wheels) and 7 STARCALS (star
calibrations) of the past 24 hours were successful, with all attitude
updates less than 0.02 degrees.
Today, a backfill of AACS (Attitude and Articulation Control
Subsystem) memory B will be sent to the spacecraft and played back to
test for corrupted memory cells. Tonight, mapping sequence M0325 and
its associated parameter files will be uploaded.
The radar system is performing nominally. Three orbits of data
using the new data management strategy which avoids tracks A2 and A4,
have been analyzed and appear to be the the most error-free to date.
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Pioneer Venus Update - 11/16/90
Date: 21 Nov 90 00:57:46 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
PIONEER VENUS STATUS REPORT
November 16, 1990
Superior Conjunction concluded on November 15. The science
complement for power sharing plan T1 will be commanded on, the bit
rate will be returned to 256 bps, and the spacecraft will be commanded
to coherent mode. A precession maneuver and HGA (High Gain Antenna)
adjustment has been scheduled for November 19, to be executed as close
to Apoapsis as possible.
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
|
| 456.203 | Magellan Update - 11/21/90 | 4347::GRIFFIN | Dave Griffin | Fri Nov 23 1990 22:55 | 38 |
| From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Date: 21 Nov 90 21:42:44 GMT
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
November 21, 1990
The Magellan spacecraft is performing well in its mapping
mode with 385 mapping orbits to date. The two momentum wheel
desaturations and seven star calibrations of the past 24 hours
were successful, with normal attitude updates.
A Deep Space Network transmitter went down temporarily
yesterday while uplinking data to the B-side memory. Of five blocks
of data, three were received successfully, and two were missed.
An attempt to repeat them later failed, but they were
repeated today along with a read-out of the memory.
The image data processing team completed the digital
processing of 12 new full resolution image mosaics, and check
prints of the products will be produced early next week.
Magellan radar mapping of Venus thus far includes 348
mapping orbits with data acquired from 344 of them. The area
covered on Venus is 93.2 degrees of longitude, less the superior
conjunction gap of 22 degrees. That was when Venus and Earth were
on opposite sides of the sun and high data rate communication was
not possible.
A similar mapping area on Earth would stretch from Los
Angeles to Iceland with the superior conjunction gap appearing
through central Greenland.
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
|
| 456.204 | PIONEER VENUS Update - November 23 | ADVAX::KLAES | All the Universe, or nothing! | Mon Nov 26 1990 20:14 | 27 |
| From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Pioneer Venus Update - 11/23/90
Date: 26 Nov 90 15:50:21 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
PIONEER VENUS STATUS REPORT
November 23, 1990
A 36-pulse precession maneuver and a HGA (High Gain Antenna)
adjustment was successfully executed by the Pioneer Venus spacecraft
on November 19. The target attitude was reached accurately enough that
no trim maneuver was required.
On November 22, a power failure at the 34 meter station in
Australia prevented loading of the SCLs. The periapsis data was lost.
The periapsis data was also lost on November 23 due to the
unavailability of adequate tracking.
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
|
| 456.205 | MAGELLAN Updates - November 24/26 | ADVAX::KLAES | All the Universe, or nothing! | Mon Nov 26 1990 20:25 | 84 |
| From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 11/24/90
Date: 26 Nov 90 20:02:13 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
November 24, 1990
At 7:11 PM (PST) on Friday, November 23, the Magellan spacecraft
entered Command Data System (CDS) safing because of errors in the
uplink command load. This upload was the normal Friday evening timing
"tweak" to optimize the radar command and pointing based on an
ephemeris update based on the last three days of tracking. A command
timing procedure was not followed and the command files were too
closely spaced in time. This timing error invoked CDS safing where:
o The High-Gain Antenna was pointed to Earth
o The Radar Sensor and Tape Recorders were turned off
o The X-band Downlink Transmitter was turned off
o Engineering telemetry was transmitted via S-band at 40 bps.
o Uplink commanding was via the low-gain Antenna at 7.8 Kbps.
At the time of the safing, the spacecraft had just completed
mapping data acquistion for orbit 887 over the western end of the
Aphrodite area (the large equatorial continent). This mapping data
was on the tape recorder ready for playback.
Magellan ground controllers worked through the night and returned
the spacecraft to execution of the onboard sequence. At 8:08 am PST
on Saturday morning, the onboard sequence resumed with the playback of
the data from orbit 887. A successful Star calibration was executed
at the midpoint of the playback providing an attitude update of 0.56
degrees. Following the playback, the spacecraft acquired data for
orbit 892. Only four orbits of data were lost.
The first Star calibration after operations resumed had an update
of only 0.06 degress. Thus, mapping restarted with good pointing.
Data acquistion since this incident has been nominal.
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 11/26/90
Date: 26 Nov 90 20:04:15 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
November 26, 1990
The Magellan spacecraft is performing nominally as it nears the
completion of orbit #906. This is the 15th mapping orbit since
mapping was resumed on Saturday morning, after the on-board computer
put the spacecraft into a safe mode Friday evening at about 7:00 PM PST.
The on-board computer detected errors in an uplink command
sequence and halted the stored mapping sequence. This safe mode kept
the High Gain Antenna pointed to Earth, so communications were not
lost. Spacecraft controllers worked through the night to correct the
command errors and re-configure the spacecraft for mapping.
High rate playback of the radar data for orbit 887 was started
shortly after 8:00 AM Saturday morning, and radar mapping resumed with
orbit 892 at 10:22 AM PST. Thus, the incident resulted in the loss of
4 orbits of radar image data. Even with this loss, we have received
on Earth 97.2% of the radar image data since mapping was started on
September 15.
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
|
| 456.206 | | PAXVAX::MAIEWSKI | | Tue Nov 27 1990 16:59 | 6 |
| Why, all of a sudden is Pioneer Venus back in the news? We get lots of
reports about signal problems they have switching the galipalator back on and
plig splat bits droped from the hydrofroster device but in general and in
layman's terms, what are they doing with it?
George
|
| 456.207 | | STAR::HUGHES | You knew the job was dangerous when you took it Fred. | Tue Nov 27 1990 17:45 | 11 |
| My guess is that it is in an extended mission phase and they are now
more interested in its data as they can correlate it with that from
Magellan.
They have reactivated Pioneer's instruments before to collect data on
Halley and, I think, some solar events.
I could dig out the original press kit if you have specific questions
about it.
gary
|
| 456.208 | | PAXVAX::MAIEWSKI | | Tue Nov 27 1990 20:28 | 9 |
| I guess the only question I'd have is to ask what they plan to do with it.
We get the details of switching various instrements on and off and that's
good but I'm curious as to what they are planning to discover by working
with it.
If any info comes along regarding Poineer Venus plans, I'd be interested.
George
|
| 456.209 | Pioneer Venus (please excuse the rathole) | 4347::GRIFFIN | Dave Griffin | Wed Nov 28 1990 02:59 | 36 |
| Magellan, for the most part, has only one function: radar mapping. It
manages to tweak out a bit more data, but Pioneer Venus remains a
powerful instrument.
The Pioneer Venus orbiter is in its extended mission. As of a few
years ago 11 of the 12 scientific instruments on the orbiter remain
fully functional (the Infrared Radiometer failed back in 1979).
There were three mission phases defined for Pioneer Venus. Phase
I (1978-1980, orbits 0-600) did most of the scientific work (in
conjunction with the probes) at low altitudes (142-250 km). Phase
II (1980-1992) has it in a higher orbit. Phase III is the reentry
maneuver which will start in May 1992 and finish in August (final orbit
will be 5002 -- according to the plan).
Several experiments: the Radar Mapper, the Neutral Mass Spectrometer,
the Ion Mass Spectrometer, and Orbiter Atmospheric Drag radio science
experiment are currently in a quiescent state awaiting reactivation in
Phase III.
Phase II is studying the solar-wind interaction and ionospheric regions
over an entire solar cycle (11 years). As an added bonus, because of
the lack of a magnetic field on Venus, it acts as an analog to a comet
when studying solar wind interaction. Lightning bursts, observed in
Phase I, are being followed up. UV cloud mapping has occurred now and
then (results compared against earth). The gamma-ray burst detector is
coordinating findings with other probes. The Halley Comet observations
have been previously mentioned. Pioneer Venus has also done
correlative work with several Venera missions.
Phase III planned additional radar mapping (although I would think
that this is now superfluous with Magellan on station); "in situ"
sampling of the ionosphere, and finally more solar-wind interaction
studies.
- dave
|
| 456.210 | | PAXVAX::MAIEWSKI | | Wed Nov 28 1990 04:20 | 3 |
| Thanks dave, that's just what I was looking for.
George
|
| 456.211 | MAGELLAN Update - November 28 | ADVAX::KLAES | All the Universe, or nothing! | Thu Nov 29 1990 13:14 | 34 |
| From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 11/28/90
Date: 28 Nov 90 22:56:53 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
November 28, 1990
The Magellan spacecraft is performing normally today and all
seven star calibrations of the past 24 hours were fully successful
with attitude updates averaging about 0.02 degrees. A new mapping
sequence was uploaded yesterday and no commanding was scheduled for
today.
The engineering telemetry indicates that the radar sensor
continues to operate normally. During the first 40 days of mapping the
radar data tapes were delivered daily from the Deep Space Network
stations. The schedule has been changed to weekly deliveries, as
planned, so the processing schedule of new image swaths and mosaics
has been affected.
The project reports that there have been, as of Tuesday, 428
orbits of radar mapping with 416.2 orbits of radar image data on the
ground.
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
|
| 456.212 | MAGELLAN Update - November 29 | ADVAX::KLAES | All the Universe, or nothing! | Thu Nov 29 1990 19:31 | 33 |
| From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 11/29/90
Date: 29 Nov 90 18:13:37 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
November 29, 1990
The Magellan spacecraft is in good health, and has completed
seven successful mapping orbits and STARCALS (star calibrations) in
the past 24 hours.
Correcting a statement made two days ago, Magellan has completed
817 actual orbits since Venus Orbit Insertion on August 10. An
adjustment was made to orbit numbers during the time prior to mapping
which skipped 11 orbits. We have completed 443 orbits of radar mapping
and have captured on Earth all but 11.8 orbits. This represents about
25% of the surface area of Venus.
The radar sensor continues excellent performance. We are waiting
for additional radar data tapes from Goldstone to continue the
analysis of the tape recorder tracks A1 and A3. Early indications
were that the rate of errors or zero-filled frames was very low.
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
|
| 456.213 | MAGELLAN Update - December 3 | PRAGMA::GRIFFIN | Dave Griffin | Tue Dec 04 1990 03:22 | 24 |
| MAGELLAN STATUS REPORT
December 3, 1990
The Magellan spacecraft's star tracker was severely affected
by noise, called a spurious interrupt, early Saturday, Dec. 1,
during a routine star calibration. As a result the attitude
control system received an incorrect attitude update, and pointed
slightly away from Earth. The spacecraft attitude degraded over
the next two orbits.
The high gain telemetry was lost, but low rate engineering
data continued to be received by the Deep Space Network stations.
The spacecaft was never in danger, but data from orbit was lost.
While commands were being prepared to correct the problem
the star tracker received a second spurious interrupt, magnifying
the attitude problem.
Commands were uplinked in two stages Saturday evening which
corrected the attitude adjustment. The next star calibration was
fully successful and mapping resumed early Sunday. The problem
caused loss of 3 l/2 mapping orbits and degraded data from two
additional orbits.
|
| 456.214 | Magellan Status Report - 12/4/90 | PRAGMA::GRIFFIN | Dave Griffin | Tue Dec 04 1990 21:58 | 31 |
|
MAGELLAN STATUS REPORT
1. The Magellan spacecraft is presently performing nominally
and the seven STARCALS of the past 24 hours were
successful with small attitude updates.
2. Magellan is now in orbit #965, so it has completed 480
radar mapping orbits. Counting the orbits lost or
degraded by this past weekend's incident, we have lost
about 18 orbits which will have to be recovered during the
extended mission.
3. Later today, the weekly mapping command sequence load will
be sent to the spacecraft along with a few routine
commands such as tertiary heater settings, etc.
4. While the SAR Processing team is awaiting the delivery of
post Superior Conjunction radar tapes, effort has been
directed toward processing "problem" data sets that have
accumulated. A software modification was made which
enabled an input data defect to be circumvented. This
made possible the processing of four new image swaths from
previously unprocessable data records. Two other image
swaths were regenerated by the High Rate Processor to
correct other problems, and were successfully processed
into good quality images.
|
| 456.215 | Magellan Status Report - 12/07/90 | PRAGMA::GRIFFIN | Dave Griffin | Mon Dec 10 1990 12:54 | 37 |
|
MAGELLAN STATUS REPORT
1. The Magellan spacecraft is presently performing nominally.
All seven STARCALS of the past 24 hours were successful
with small attitude updates.
2. Today the weekly update of radar control parameter and
mapping quaternion files will be sent to the spacecraft.
3. At 4:30 AM PST Magellan completed its 500th mapping orbit
and almost 97% of this data has been successfully
transmitted to the Earth.
4. The error rate on Tracks 1 and 3, now being used on Tape
Recorder A, continues to climb, exhibiting similar
behavior that was experienced on Tracks 2 and 4. We are
expediting completion of a single tape recorder strategy
which will use Tape Recorder B solely and may be
implemented as early as 14 December.
5. The single tape recorder approach would result in gaps of
about ten seconds when the tape recorder switches from one
track to another. Since the radar is mapping about 8
kilometers of the surface in each second, the potential
gaps would be about 80 kilometers. But because of the
actual beam width of the radar, the gaps would vary from
60 to 70 kilometers.
6. In the absence of engineering constraints, mission
planning and the science team will determine if and when
we will switch from the dual to the single tape recorder
strategy and placement of gaps on the surface within the
operational flexibility to adjust their locations.
|
| 456.216 | Magellan image(s) available | PRAGMA::GRIFFIN | Dave Griffin | Wed Dec 12 1990 00:27 | 12 |
| I have the first of two Magellan radar mosaics available online (in both
GIF and DDIF formats). The second one may not be available for a few more
days (possibly a week).
Still, it is stunning, considering it is radar and not a photograph!!
Pragma::Public:[NASA]MGN_Mosaic_1.GIF (GIF file)
.IMG (DDIF image)
.INFO (Technical information)
- dave
|
| 456.217 | MAGELLAN Updates - November 30-December 11 | ADVAX::KLAES | All the Universe, or nothing! | Wed Dec 12 1990 18:45 | 400 |
| From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 11/30/90
Date: 11 Dec 90 03:52:10 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
[Note: We had a disk crash about a week ago on our computer, it was finally
brought back up fully opertational today. I've got a backlog of status
reports that I will be posting to the net shortly.- Ron Baalke]
MAGELLAN STATUS REPORT
November 30, 1990
The Magellan spacecraft is in good health, and has completed seven
successful mapping orbits and STARCALS (star calibrations) in the past 24
hours. There were no uploads to the spacecraft yesterday. Later today, the
weekly "tweak," an update of mapping parameters, will be sent.
We have completed 450 orbits of radar mapping and have captured on the
Earth all but 11.8 orbits. This represents about 25% of the surface area of
Venus.
The radar sensor continues excellent performance. A test image swath
processed from orbit #921 gives an indication of higher than normal rate of
zero-filled data frames. This may signal the start of some performance
degradation on tape recorder tracks A1 & A3. A radar calibration test
performed early yesterday is expected to demonstrate the present condition of
track A2.
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 12/03/90
Date: 11 Dec 90 04:00:15 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
December 3, 1990
The Magellan spacecraft, presently performing nominally, experienced an
incorrect attitude update on Saturday, December 1, which degraded the radar
mapping data of several orbits and affected the X-band communications. Early
Saturday morning, the star tracker accepted a spurious interrupt and incurred
an incorrect attitude update of 0.136 degrees. The on-board drift bias was
also corrupted so that the attitude knowledge degraded with time, and
eventually was off by about 0.4 degree.
This off-point made it impossible to achieve a reliable X-band lock and
radar data for several orbits was lost. S-band telemetry was maintained, and
the spacecraft was never in danger. Spacecraft controllers were initially
confident that a successful star calibration would correct the attitude error,
but another spurious interrupt further degraded the off-point to 1.1 degrees.
Attitude corrections were computed on the ground and uplinked to the
spacecraft on Saturday evening in two stages. At 8:22 PM PST the orbit #946
STARCAL (star calibration) was successful on both stars. On subsequent orbits
the drift bias value was updated, and by Sunday morning the attitude update
limit was reset to it normal value of 0.07 degree. The net result was degraded
radar data for 2-1/2 orbits and lost radar data for 3-1/2 orbits. The
Magellan flight team will examine ways to accelerate the recovery process in
the event of incorrect attitude updates.
Of the 450 orbits completed by November 30, 438 orbits of valid data have
been received at earth (97.3%). The causes of data losses are as follows:
o Power outage at Madrid DSN station (10/1) 1.2 orbits
o Incorrect attitude update (10/1) 1.5 orbits
o DSN delay is setting polarization after
TWTA swap following spurious shutoff 0.3 orbits
o Frequency timing outage Canberra (11/13) 1.4 orbits
o Loss of Signal #3 (11/15) 3.0 orbits
o Power outage at Canberra (11/21) 0.2 orbits
o Tweak Commanding anomaly (11/23) 4.0 orbits
o Miscellaneous DSN lockup delays, etc. 0.4 orbits
TOTAL TO DATE: 12.0 ORBITS
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 12/04/90
Date: 11 Dec 90 04:10:43 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
December 4, 1990
The Magellan spacecraft is presently performing nominally and the seven
STARCALS (star calibrations) of the past 24 hours were successful with small
attitude updates. Magellan is now in orbit #965, so it has completed 480
radar mapping orbits. Counting the orbits lost or degraded by this past
weekend's incident, we have lost about 18 orbits which will have to be
recovered during the extended mission.
Later today, the weekly mapping command sequence load will be sent to
the spacecraft along with a few routine commands such as tertiary heater
settings, etc.
While the SAR (Synthetic Aperture Radar) Processing team is awaiting the
delivery of post Superior Conjunction radar tapes, effort has been directed
toward processing "problem" data sets that have accumulated. A software
modification was made which enabled an input data defect to be circumvented.
This made possible the processing of four new image swaths from previously
unprocessable data records. Two other image swaths were regenerated by the
High Rate Processor to correct other problems, and were successfully processed
into good quality images.
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan article
Date: 11 Dec 90 04:19:03 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
The Washington Post
Venus Appears Volcanically Active
By Kathy Sawyer
"The Magellan robot explorer has sent back data showing that the face
of Venus is not an ancient death mask, like those of Mars and Mercury,
but has been remodeled piecemeal by volcanic flows, scientists
reported today."
The Sawyer piece quotes JPL/Magellan chief scientist Steve Saunders
"Venus is not dead. ...It did not shut down 400 million years ago."
Only Earth and two planetary moons, Jupiter's Io and Neptune's Triton
are known to exhibit any form of volcanism, according to the Post.
The first scientific papers resulting from Magellan's initial data
were presented at the fall meeting of the American Geophysical Union
in San Francisco.
Included in the Post report was evidence of volcanism reported at the
meeting. This included unexpected smooth areas on the Venus surface,
vast expanses without craters. Rapid volcanic resurfacing could hold
the answer to the riddle that craters are not being found in the
process of being resurfaced.
The Post reported that Venus' rate of resurface, 0.1 cubic mile per
year, is far outpaced by Earth which has an output of 7.7 cubic miles
a year. Said Southern Methodist University's Roger Phillips, "Maybe
only 10 percent of the planet is active at any one time."
Other evidence gathered included some volcanoes with craters nearby and
some without; a wide variety in the thickness of the molten rock flowing
on Venus; indicating possibility of Venus quakes, the story revealed.
Said Brown University's James Head, "it's Christmas every day,"
referring to the evidence after years of waiting for planetary
scientists, according to the Post.
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 12/05/90
Date: 11 Dec 90 04:28:25 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
December 5, 1990
The Magellan spacecraft is presently performing nominally and the seven
STARCALS (star calibrations) of the past 24 hours were successful with small
attitude updates. Yesterday, mapping sequence M0339 and its associated
parameter files was uploaded and began executing at 3:48 AM PST this morning.
The radar sensor continues to operate normally. However, analysis of
data from orbits #958 & 959 indicates that tape recorder tracks A1 and A3 are
beginning to show the progressive deterioration that affected tracks A2 and A4.
A tape management strategy using only tape recorder B is currently being
evaluated. The 1.8 megabits of radar data from each full mapping pass requires
four tape recorder tracks. If only one recorder is used, small gaps occur
when the recorder switches from one track to another.
The strategy up to this time has been to use both tape recorders, so the
second unit is recording as the first reaches the end of a track and no gaps
occur. It may be possible to design a strategy which uses tape recorder A
only to fill the gaps.
The SAR (Synthetic Aperture Radar) Data Processing Team produced five
standard image swaths on Monday, December 3, three from reprocessed data
records. On December 4 they produced a test image swath from orbit #951
and twelve standard image swaths from orbits #790 thru 803. The quality is
normal except for a small "bright patch" at about 13 degrees south latitude.
This patch is a result of a faulty SAR threshold value for one burst of SAR
data. It is considered to be a minor problem, but it is being investigated
and appropriate corrections will be made.
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 12/06/90
Date: 11 Dec 90 04:32:29 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
December 6, 1990
The Magellan spacecraft is presently performing nominally. Six of the
seven STARCALS (star calibrations) of the past 24 hours were successful with
attitude updates averaging about 0.02 degrees. No commands were sent to the
spacecraft during the past 24 hours. The weekly "tweak" of radar parameters
files is scheduled for tomorrow.
The radar sensor is operating normally. The Radar System Engineering
Team is continuing to analyze the performance of the on-board tape recorders.
Yesterday, a telephone conference on the tape recorder A bit error problem was
conducted with engineers at Martin Marietta and Odetics, manufacturer of the
tape recorder. Odetics currently believes the most likely cause is skew of
the record and/or playback heads. They are just beginning to analyze the
telemetry data in conjunction with JPL and MMC, and will develop a test plan
for tests which can be conducted on the spacecraft as well as a spare tape
recorder here on Earth. The next meeting will be held at JPL on Thursday,
December 13.
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 12/07/90
Date: 11 Dec 90 04:38:46 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
December 7, 1990
The Magellan spacecraft is presently performing nominally. All seven
STARCALS (star calibrations) of the past 24 hours were successful with small
attitude updates. Today the weekly update of radar control parameter and
mapping quaternion files will be sent to the spacecraft. At 4:30 AM PST
Magellan completed its 500th mapping orbit and almostof this data has
been successfully transmitted to Earth.
The error rate on Tracks 1 and 3, now being used on Tape Recorder A,
continues to climb, exhibiting similar behavior that was experienced on Tracks
2 and 4. A single tape recorder strategy is being developed which will use
Tape Recorder B solely and may be implemented as early as December 14. The
single tape recorder approach would result in gaps of about ten seconds when
the tape recorder switches from one track to another. Since the radar is
mapping about 8 kilometers of the surface in each second, the potential gaps
would be about 80 kilometers. But because of the actual beam width of the
radar, the gaps would vary from 60 to 70 kilometers.
In the absence of engineering constraints, mission planning and the
science team will determine if and when the switch from the dual to the single
tape recorder strategy and placement of gaps on the surface within the
operational flexibility to adjust their locations.
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 12/10/90
Date: 11 Dec 90 04:42:54 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
December 10, 1990
The Magellan spacecraft is presently performing nominally. All STARCALS
(star calibrations) over the weekend were successful with small attitude
updates. On Friday, December 7, the weekly update of radar control parameter
and mapping quaternion files was successfully sent to the spacecraft.
Thermal and power effects of solar occultation are beginning to be seen.
The spacecraft temperatures drop while in the shadow of Venus and the battery
charge levels are slightly lower. Starting on Saturday, December 15, we will
have periods of Earth occultation, when the playback of data to Earth is
blocked by Venus.
Spacecraft controllers are still analyzing the performance of on-board
tape recorder A and designing a data management strategy which uses just tape
recorder B. The single tape recorder approach would result in gaps of about
ten seconds when the tape recorder switches from one track to another. Since
the radar is mapping about 8 kilometers of the surface in each second, the
potential gaps would be about 80 kilometers. But because of the actual beam
width of the radar, the gaps would vary from 60 to 70 kilometers. A technical
meeting with representatives of Odetics and Martin-Marietta is scheduled for
December 13 at JPL to discuss the tape recorder and possible corrective actions.
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 12/11/90
Date: 11 Dec 90 21:43:29 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
December 11, 1990
The Magellan spacecraft is in good health and performing nominally. All
seven STARCALS (star calibrations) since yesterday were successful with
attitude updates averaging less than 0.015 degree. There were no commands
sent to the spacecraft yesterday, but later today the M0346 mapping command
sequence will be sent. This 4-day command sequence is the last sequence
containing full length mapping passes as we go into the occulted mapping
phase of the mission.
From December 14 until January 28, part of the playback phase of each
orbit will be occulted by Venus. To adjust for the shorter playback time
available, the length of the mapping passes are shortened. During the first
eight days of occulted mapping, the pass is shortened by 6.5 minutes. At
the peak of apoapsis occultation the mapping passes will be shortened by
about 9 minutes.
The so-called "occultation gap" will be split between the northern and
southern extremes of the image swaths. The total area which will be lost is
about 1% of the Venus surface. The gaps is expected to be filled-in between
August 15 and September 28 1991, during the Extended Mission Cycle 2.
The radar sensor continues its excellent performance, but the tape
recorder tracks A1 and A3 are exhibiting an exponential rate of deterioration.
Various corrective actions are being studied.
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
From: 17001_1511@uwovax.uwo.ca
Newsgroups: sci.astro
Subject: Re: Re: Magellan article on erosion
Date: 12 Dec 90 14:21:34 GMT
Venus erosion:
The point about vast smooth areas on Venus that was queried on the net
is that erosion seems unable to account for them. Magellan is giving us two
conflicting observations: craters in numbers that suggest a surface age of
several hundred million years (up to a billion) but none that are eroded.
Well, maybe one or two slightly smoothed by erosion, but not many, and not
much of the vast expanse of faulted terrain or volvanic features look
eroded either - but craters are a better indicator because we know so much
about what they ought to look like from the Moon and elsewhere. If we had
active erosion we should see differences between old and young craters. One
solution is to say all the old craters were swallowed up in an ocean of
lava in one gigantic eruption or series of eruptions a few hundred million
years ago. Then the ones we see formed over the years but are hardly eroded
at all. Faint streaks do suggest wind action, as on Mars, but that is not
yet confirmed. In any case it must be ineffective as an agent of erosion.
Incidentally, the Soviet Venera 13 lander in 1982 photographed clods of
dust moving around, on the lower ring of the spacecraft. It may have been
spacecraft vibration that moved the dust, but wind is also a possibility.
Phil Stooke,
Department of Geography,
University of Western Ontario,
London, Ontario, Canada N6A 5C2
|
| 456.218 | MAGELLAN Update - December 12 | ADVAX::KLAES | All the Universe, or nothing! | Thu Dec 13 1990 17:48 | 44 |
| From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 12/12/90
Date: 13 Dec 90 00:06:58 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
December 12, 1990
The Magellan spacecraft is in good health and performing
nominally. All seven STARCALS (star calibrations) since yesterday
were successful with attitude updates averaging less than 0.01 degree.
The M0346 mapping command sequence and its associated parameter
files was sent to the spacecraft yesterday and is now executing. This
4-day sequence provides a transition to the Occulted Mapping phase of
the mission which extends from December 14 until January 28. During
this period Venus is between the spacecraft's antenna and Earth for
part of each orbit during the downlink time. As a result, part of the
mapping of each orbit will be missed. This period was included in
pre-launch planning. During this period, mapping sequences will be
sent to the spacecraft on Fridays.
The radar sensor continues its excellent performance, but
analysis of the radar data from orbits #1009 and 1010 verify that tape
recorder tracks A1 and A3 are exhibiting an exponential rate of
deterioration. A technical discussion of the tape recorder problem
between engineers from JPL, Martin-Marietta, and Odetics is scheduled
for tomorrow.
Twelve new full-resolution image swaths were produced, including
one using an engineering version of the SAR (Synthetic Aperture Radar)
processing software. This version compensates for a defect discovered
in the radar data of orbit #635. The SAR processor has completed
processing of all available experiment data records.
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
|
| 456.219 | MAGELLAN Update - December 13 | ADVAX::KLAES | All the Universe, or nothing! | Fri Dec 14 1990 18:28 | 84 |
| From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 12/13/90
Date: 13 Dec 90 20:47:57 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
December 13, 1990
The Magellan spacecraft is in good health and performing
nominally. All seven STARCALS (star calibrations) since yesterday
were successful with small attitude updates.
The spacecraft commanding at present includes updating of
reference values such as the Z axis gyro bias. Tomorrow, however, the
M0349 mapping sequence will be sent up, which is the first of six
occulted mapping sequences. This sequence will shorten the mapping
pass by 6.5 minutes in order to accommodate 46 minutes of Earth
occultation during the playback.
Spacecraft engineers are meeting today with representatives of
Odectics, the company which built the on-board tape recorder to
discuss the probable causes of the tape recorder A deterioration and
options for correcting the problem.
96.7% of the radar data has been received at Earth. The
following table shows the causes of data losses:
Power outage at Madrid DSN station (10/1) 1.2 orbits
Incorrect attitude update (10/1) 1.5 orbits
DSN delay is setting polarization after
TWTA swap following spurious shutoff 0.3 orbits
Frequency timing outage Canberra (11/13) 1.4 orbits
Loss of Signal #3 (11/15) 3.0 orbits
Power outage at Canberra (11/21) 0.2 orbits
Tweak Commanding anomaly (11/23) 4.0 orbits
Incorrect attitude update (12/1) 4.5 orbits
Miscellaneous DSN lockup delays, etc. 0.4 orbits
TOTAL TO DATE: 16.5 ORBITS
Eight images have been selected for a Magellan Results lithograph
set to be distributed Lab-wide early in 1991. A 10 foot by 12 foot
photomural of the "Crater Farm" Magellan image has been hung on the
wall opposite the entrance to the Smithsonian National Air and Space
Museum in Washington, D.C., and a continuous video presentation which
includes the press conference is playing on the main floor near the
Viking Mars probe display.
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan article
Date: 13 Dec 90 22:39:16 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
Associated Press -- 12/12/90
"Venus Magellan"
"An alignment of the planets will interfere with the Magellan
spacecraft's ability to send pictures of Venus back to Earth for the
next six weeks beginning Sunday, NASA says."
The AP reports that in late October and early November the sun was
between Venus and Earth, forcing a two-week halt to Magellan's $744
million mission to use radar to map the surface of cloud-shrouded Venus.
Now, the AP says, it is the planet Venus itself which is getting in
the way, although the mapping mission will continue.
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
|
| 456.220 | More images... | PRAGMA::GRIFFIN | Dave Griffin | Sat Dec 15 1990 15:15 | 14 |
| Re: .216
I wasn't able to get the one additional Magellan image -- I got three!
GIF, DDIF (greyscale), and technical data available at:
pragma::public:[nasa]MGN_Mosaic_2.whatever
MGN_Lakshmi_1
MGN_Ushas_Mons_1
Visually, the first mosaic was the most impressive. I find these
images more geologically fascinating.
- dave
|
| 456.221 | Comment on the press | 19458::FISHER | I like my species the way it is" "A narrow view... | Mon Dec 17 1990 16:28 | 21 |
| >Associated Press -- 12/12/90
>"Venus Magellan"
>
>"An alignment of the planets will interfere with the Magellan
>spacecraft's ability to send pictures of Venus back to Earth for the
>next six weeks beginning Sunday, NASA says."
>
>The AP reports that in late October and early November the sun was
>between Venus and Earth, forcing a two-week halt to Magellan's $744
>million mission to use radar to map the surface of cloud-shrouded Venus.
>
>Now, the AP says, it is the planet Venus itself which is getting in
>the way, although the mapping mission will continue.
Yeah, stupid NASA went and let the planets get in the way. Why do we keep
giving those screw-ups money?
<sigh>
Burns
|
| 456.222 | MAGELLAN Update - December 17 | ADVAX::KLAES | All the Universe, or nothing! | Mon Dec 17 1990 20:47 | 34 |
| From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 12/17/90
Date: 17 Dec 90 21:04:22 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
December 17, 1990
The Magellan spacecraft is in good health and performing
nominally. All STARCALS (star calibrations) and DESATS (desaturations
of the reaction wheels) during the weekend were successful.
The spacecraft is now executing the first of six occulted mapping
sequences. This sequence will shortens the mapping pass by 6.5
minutes in order to accommodate 46 minutes of earth occultation during
the playback. Although the period of earth occultation changes with
each orbit, the timing for the mapping sequence is adjusted for the
maximum occultation in the week.
The radar sensor health continues to operate normally. Seven
full resolution image swaths were processed by the SAR (Synthetic
Aperture Radar) Data Processor on December 13. The rate of image
production has continued to be paced by the delivery schedule of new
SAR tapes.
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
|
| 456.223 | | 30086::REITH | Jim Reith DTN 226-6102 - LTN2-1/F02 | Tue Dec 18 1990 10:42 | 3 |
| Was it determined at last weeks meeting, what they are going to do
about the degrading tape recorder tracks? Are they going to go to
single recorder mode?
|
| 456.224 | The recorders | 15372::LEPAGE | Life sucks then the bill comes in | Tue Dec 18 1990 14:31 | 10 |
| Re:.223
Last I heard they were going to switch to single recorder
operations. The manufacturer of the recorders, Odetics, is examining
the problem. They believe that the heads on the recorder have gone out
of alignment. They are examining what (if anything) can be done to
correct the problem.
Drew
|
| 456.225 | PIONEER VENUS Update - December 18 | ADVAX::KLAES | All the Universe, or nothing! | Tue Dec 18 1990 17:24 | 29 |
| From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Pioneer Venus Update - 12/18/90
Date: 18 Dec 90 16:16:33 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
PIONEER VENUS STATUS REPORT
December 18, 1990
The last periapsis occultation occurred on December 9.
The first of a series of Pioneer Venus/Magellan dual down-link
tracks began on December 9 from the 70 meter tracking station in Australia.
The bit rate was increased to 1024 bits/second during the track.
The precession maneuver on December 10 was unsuccessful. An
incorrect time delay, compounded by CPA (Command Processor Assembly)
problems at the 34 meter antenna in Spain, resulted in only one pulse
instead of the planned 25 pulses. The maneuver was repeated successfully
on December 12. The next maneuver will be performed on December 28.
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
|
| 456.226 | MAGELLAN Update - December 18 | ADVAX::KLAES | All the Universe, or nothing! | Tue Dec 18 1990 19:04 | 40 |
| From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 12/18/90
Date: 18 Dec 90 18:47:17 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
December 18, 1990
The Magellan spacecraft continues to be in good health and is
performing nominally. All STARCALS (star calibrations) and DESATS
(desaturations) during the past 24 hours were successful.
The Project is currently in the Occulted Mapping Phase of the
mission. Each mapping pass is shortened by 6.5 to 9 minutes in order
to accommodate Earth occultation during the playback. The period of
earth occultation varies from 46 to 58.5 minutes. The area missed
because of the shorter mapping pass is split between the north and
south ends of the image swath.
The radar sensor health continues to operate normally. Fifteen
full resolution image swaths were processed by the SAR (Synthetic
Aperture Radar) Data Processor since the morning of December 14,
including 11 standard swaths, 3 special products and one temporary
image from orbit #1032.
Analysis of image swaths from orbit #1023 and after revealed some
small gores (spaces between adjacent swaths) near the periapsis
(lowest point in the orbit). It has been determined that this was a
result of a slight error in the mapping quaterions, and will be
corrected on an upcoming update of the mapping quaternion file.
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
|
| 456.227 | Blob tectonics on Venus | ADVAX::KLAES | All the Universe, or nothing! | Wed Dec 19 1990 16:30 | 77 |
| From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Venus article
Date: 19 Dec 90 04:10:01 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
Science News -- December 15, 1990
"Blob Tectonics on Venus"
Planetary scientists have debated for more than a decade where some form
of the plate tectonics that shaped Earth also molded the surface of Venus.
Now two researchers suggest that some of the most dramatic features on Venus
result not from plate tectonics, but from a process they call "blob
tectonics".
On Earth, the Hawaiin Islands and some other island chains represent one
classic manifestation of plate tectonics. Such island chains apparently
formed when a "hot spot" -- a plume of hot rock rising from the planet's
interior -- broke through the crustal plate overhead. Over millions of years,
towering volcanic peaks arose, which got carried away by the moving plate.
As proposed by Robert R. Herrick and Roger J. Phillips of Southern Methodist
University in Dallas, blob tectonics would involve gigantic, single "blobs"
of hot materials rising like bubbles. These deformed and sometimes punched
through a stationary Venusian surface, the Dallas scientists suggest.
Four examples of such blobs may underlie Aphrodite Terra, a hilly region
that stretches at least 10,000 kilometers along Venus' equator, Herrick and
Phillips say. Beta Regio, one of the first features on the planet identified
as volcanic in origin, may offer another candidate site for blob tectonics.
"A basic tenet of this model is that tectonism and magmatism (the
formation of molten material) at Beta Regio and western Aphrodite are
dominated by the evolution of plume heads or blobs as they rise to the base of
the lithosphere and spread laterally," the authors write in the November
Geophysical Research Letters. The lithosphere contains the planet's crust
and the uppermost mantle.
One clue to the presence of four separate blobs at Aphrodite Terra
comes from variations in the planet's gravity, which indicates regions of
lower-density materials in the mantle at different depths. The density
measurements -- made by tracking the rises and dips in altitude of the
orbiting U.S. satellite Pioneer Venus (which reached Venus in 1978) and
Magellen (which arrived last August) -- show one less-dense area about 15 km
down in a circular area roughly 2,500 km across. A second area lies 70 km
down in an elliptical shape some 3,500 km long; a third appears as a 2,500
km circle at a depth of 80 km, and a fourth lies about 100 km below the
surface, forming a circular feature 3000 km across.
If the theory is correct, Magellan's sharp radar images will reveal
specific surface features resulting from rising, individual blobs, Phillips
says. He and other Magellan scientists are looking for elevated regions
cracked by faults in more than one direction and areas that lack meteorite
impact craters, as if existing craters have been covered by massive volcanic
flows.
Phillips says processing of Magellan's radar images of western
Aphrodite Terra should begin later this month at NASA's Jet Propulsion
Laboratory in Pasadena, Calif. Magellan will not image Beta Regio until
next spring.
[Magellan started imaging Aphrodite Terra around November 16, and as mentioned
in the article, this region stretches 10,000 km, and Magellan will continue
to image this region until March 1, 1991. When Magellan went into orbit
around Venus last August 10, it was already over Beta Regio. Since radar
mapping did not start until September 15, Magellan will have to wait until
the next go around until it obtains images of Beta Regio, which will be on
April 7, 1991. - Ron Baalke]
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
|
| 456.228 | | 19458::FISHER | I like my species the way it is" "A narrow view... | Thu Dec 20 1990 12:38 | 10 |
| A radio news article I heard yesterday seems to indicate that they have decided
to shut down one of the tape recorders (I assume due to the defective tracks
that are showing up). This would cause some data loss "while the operating
recorder is rewinding"??
Can anyone throw any more light on this? Is it the time between the end
of playback to Earth and the time that mapping should begin when the recorder
does not have time to rewind?
Burns
|
| 456.229 | Track change time = ~10 seconds | 30086::REITH | Jim Reith DTN 226-6102 - LTN2-1/F02 | Thu Dec 20 1990 13:59 | 6 |
| My understanding was that it records on single tracks at a time and
when it changes tracks it loses about 10 seconds of data which amounts
to about 60-70km of ground track. Why not use the faulty recorder to
cover during these short bursts. Get something which should be better
than not bothering to do anything (there must be a minute of reasonable
tape in the bad recorder somewhere ;^)
|
| 456.230 | MAGELLAN Update - December 20 | ADVAX::KLAES | All the Universe, or nothing! | Fri Dec 21 1990 20:01 | 62 |
| From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 12/20/90
Date: 20 Dec 90 23:35:01 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
December 20, 1990
The Magellan spacecraft continues to be in good health and is performing
nominally. All STARCALS (star calibrations)and DESATS (desaturations of the
reaction wheels) during the past 24 hours were successful. The average
attitude update of the previous 24 hours was 0.008 degree.
This morning, at 3:22 AM (PST), the X-band transmitter (TWTA-B)
experienced a spurious shutoff and switched to TWTA-A. Communications were
restored 30 minutes later, but since the spacecraft was performing playback
from the error-filled tape recorder A, it was not possible to establish frame
synchronization of the data. Uploads later today will clear the fault
protection flags and update other spacecraft parameters.
Yesterday morning, between 9:30 and noon PST, high winds in the desert
forced the DSN (Deep Space Network) to put the Goldstone antennas in their
stowed position. This resulted in the loss of the first half of data playback
from orbit #1076. High winds predicted for today may again require the DSN to
suspend tracking.
The following is a report of the results of the JPL, MMC (Martin Marietta
Corporation), and Odetics tape recorder technical meeting on December 19:
o An analysis by Odetics was not successful in duplicating the error
rate signature by introducing the typical intersymbol interference
and tape problems they have experienced with similar recorders over
20 years.
o Odetics believes the Magellan problem may be unique and may be
upstream in the encode process or in the data source. However,
JPL experts believe they can simulate the error signature by
introducing a sync slip in the playback mode.
o An exchange of analysis results and a follow-up technical
discussion by telecon is scheduled for today.
o Odetics proposed a series of flight and ground tests which will
be reviewed in detail by JPL and MMC.
o Test execution planning will be initiated over the holidays and
all experts will assemble at JPL on January 7-9 to finalize test
plans which will be presented to the Mission Director for approval
on January 9.
o In the meantime, we remain on schedule to implement the single
tape recorder strategy on December 22.
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
|
| 456.231 | Plans for the MAGELLAN Extended Mission | ADVAX::KLAES | All the Universe, or nothing! | Fri Dec 21 1990 20:03 | 542 |
| From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Extended Mission Update
Date: 20 Dec 90 23:04:27 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
[Forwarded from Tony Spear, Magellan project manager......Ron Baalke]
OUTLOOK FOR
MAGELLAN EXTENDED MISSION
December 19, 1990
Summary: This paper addresses science rationale, data
acquisition, and spacecraft survival for a Magellan
Extended Mission. Early mapping results are
exciting, indicating that geological pro-
cesses are complex and perhaps active on the
surface of Venus. An Extended Mission will
provide much more data for a wider and more
thorough investigation and interpretation.
Despite problems, there is a good chance
that the spacecraft will survive until mid decade.
The tape recorders may be the first to reach
end of life in Extended Mission mapping.
1. The primary mapping mission timeframe is defined to be the
period of 243 days from 15 September 1990 to 15 May 1991.
2. Greater than 70% of the surface of Venus is estimated to
be mapped at the end of this 243 day primary mission
cycle, cycle 1. The Extended Mission is structured into
subsequent 243 day cycles.
3. In the Extended Mission we will acquire:
a. The remainder of the global map including the South
Pole which has never imaged.
b. A hi-resolution gravity map for the first time on Magellan.
c. Radar images from multiple view angles providing
for same and opposite side stereo and generally
enhancing the ability to interpret surface processes.
d. Images of selected surfaces from one cycle to
another for detection of changes.
e. Hi-resolution surface topographic map.
4. Early mapping results indicate that surface processes
(tectonic, volcanic and eolian) are complex, perhaps
active, and are varied and detailed to the level of the
radar resolution. Surprising surface patterns are being
imaged, challenging the scientist's ability to explain
the processes. Many questions concerning the fundamental
geologic evolution of Venus and its similarity to Earth
remain unanswered.
In addition to completing the global map, the Extended
Mission provides an opportunity to exploit the capabilities
of the radar instument to maximize scientific return.
Multiple view angles, demonstrated on Seasat and SIR to be
significant to interpretation, are planned along with
stereo imaging and the acquisition of hi-resolution altimetry.
These data sets will be used to obtain a thorough under-
standing of geologic processes. The early cycles will con-
centrate on global-scale processes, e.g. evidence for plate
recycling, while later cycles will provide more detailed
studies, e.g. stereo images of volcanic features, for more
understanding of local-scale geologic features.
The global geologic data set acquired over this oppor-
tunity at Venus will be the most comprehensive for any
planetary body, in particular for one of this size. It
will become a most important data set for comparative
planetary analysis in understanding Earth's past and
in forecasting Earth's future.
5. A workshop held in July 1990 completed the science
rational and a data acquisition strategy for a baseline
Extended Mission lasting six cycles, cycles 2 through 7.
6. The Extended Mission science rationale is defined in
the Magellan Document "Science Augmentation and Extended
Mission" dated 1 December 1990.
7. For POP 91-1, generated and reviewed in January and
February 1991, three Extended Mission cycles are being
planned and budgeted.
8. A summary of the data acquisition strategy is as follows:
a. In cycles 2 and 3, gap filling and the South Pole
coverage is first priority. In addition, observations
will be made from the opposite "look direction" at a
a constant incidence angle of approximately 25 degrees.
b. Beginning in the latter part of cycle 2 and through
cycles 3 and 4, one of four orbits will be dedicated
to acquiring gravity data around periapsis when peri-
apsis is in view of Earth. During this time, the
high gain antenna will remain pointed to Earth instead
of being pointed to the surface to acquire radar data.
c. Beginning with cycle 2, comparisons of images from one
cycle to another will be initiated. In addition, gen-
eration of same and opposite side stereo images plans
will begin.
d. In cycle 4, we will begin to exploit other radar modes
such as spotlighting, dwelling on a scene as we pass by,
and hi-resolution altimetry using the high gain antenna.
9. Two experiments, if found to be feasible, can substantially
enhance science return in the Extended Mission:
a. Radar Interferometry, demonstrated with SEASAT,
SIR, and aircraft radar data, could allow for surface
profiling to a meter accuracy over the footprint at
the radar resolution and surface change detections
on the order of centimeters.
b. Aerobraking the spacecraft into a circular orbit
would provide for very high resolution gravity data
and VOIR like hi-resolution radar data (note 1) at
all latitudes. While interferometry radar may be
feasible in an elliptical orbit, this experiment
can work better in a circular orbit.
______________________________________________________________
Note 1: VOIR Hi-Resolution Mode: 75 M Azimuth by 75 M range
resolution, 4 looks, constant
look angle at all latitudes
MGN Elliptical Orbit: 125 M Azimuth and 125 M to
400 M range resolution, 4-12
looks and look angle from 15
to 45 degrees as a function
of latitude
MGN Circular Orbit: 50 M Azimuth and 100 M range
resolution, 4 looks, constant
look angle at all latitudes
_______________________________________________________________
10. Two small studies will be conducted in the period January
through March 1991 to determine feasibility of these radar
interferometry and aerobraking experiments.
11. These studies will determine if it is worthwhile to initiate
detailed planning and implementation for these experiments
in FY'92. Study results will be examined by a review board.
12. In addition, the Extended Mission plan will be examined by
a review board in April 1991.
13. As Hughes Aircraft radar engineers phase off the project in 1991,
they will be replaced by personnel from JPL's section
334, Radar Science and Engineering section, who will
assume radar operations responsibility in 1991 in
addition to its radar data processing responsibility.
An initial transition plan has been developed which
also incorporates a processor upgrade plan. The
processor upgrade will address:
a. Reprocessing the global map at full resolution
using the best available gravity, topographic
models and ephemeris solutions.
b. Phasing out rapidly aging processing hardware.
c. Additional throughput capability to handle both
reprocessing and new data processing loads.
d. "Two pass" processing for better quality control.
e. Interferometric radar data processing.
14. Martin Marietta will continue to operate the spacecraft through-
out the Extended Mission from their remote operations
facility in Denver.
15. With an Extended Mission, the following project data
processing plan is being implemented:
a. Continue standard processing consisting of full
resolution (currently budgeted for 15% of the
planet) and compressed mosaics as already planned
for the primary mission.
b. Continue development of special products in
support of conferences and reports, most likely
at a greater rate that was initially anticipated.
c. Reprocess data which have problems (note 2) at a
lower priority than a. and b. above, except when re-
processing is necessary to develop a desired special
product. Emphasis will be placed on processing new data.
__________________________________________________________________
Note 2: Such as the data with bit flips and slips due to the
tape recorder A problem which is a major processing
effort requiring additional processing development.
__________________________________________________________________
d. A globe surfaced with compressed mosaics will be developed
as standard mosaic products become available, as planned.
e. In addition, we will initiate planning in FY'92 to
reprocess the global radar data set at full resolution
using the best terrain and navigation models which can
be achieved with the composite PVO (Pioneer Venus Orbiter),
Venera, Magellan gravity and topographic data. This is new,
and the target date for completion is the end of FY'93.
f. Within funding, the "flight over the Venusian
surface" movie will be improved using the best
imaging and topographic model available.
g. Implementation of "adaptive flight" over the surface
of Venus will be initiated in FY'92. Adaptive flight
means being able to navigate over the surface data
base under the control of the operator, "pilot",
using a joy stick.
h. Release of science products, either in interim
or in final form, will be accomplished as soon
as possible. In FY'91 the following releases
are scheduled:
1. 3 Day CD-ROM by January 1991
2. 45 Day CD-ROM by April 1991
3. 4 month CD-ROM by June 1991
4. 8 month CD-ROM by October 1991
In the Extended Mission, CD-ROMs will be issued on 4 month centers.
In addition the following reports will be released.
1. 45-day Report submitted in January of 1991
to Science Magazine
2. 6-month Report submitted in March of 1991
to the Journal of Geophysical Research
3. Prime Mission Report by October 1991
4. Global Radar Report by October 1992
5. Geoscience Report by October 1993
6. Circular Orbit Mission Report by October
1995 (if accomplished)
7. Interferometric Radar Report by October
1995 (if accomplished)
16. With regard to spacecraft survivability in the Extended Mission,
here is status on problems:
a. Thermal: Absorptivity for the optical surface re-
flectors continues to degrade past its end of life
value. This poses problems on cycles 2, 4 and 6 when
the high gain antenna does not shade the spacecraft body and
REMs (Rocket Engine Modules) sufficiently to keep certain
temperatures within limits during normal operations for mapping.
Flight software is under development to permit maneuvering
in cycle 2 to either alternate sides of the spacecraft exposed
to the Sun or to "hide" behind the high gain antenna
for periods of time on each orbit.
This thermal problem represents additional software
development and operations complexity. This is cur-
rently a high priority task now underway for cycle 2.
In addition, certain spacecraft subsystems will run some-
what hotter than generally the norm for an inter-
planetary spacecraft which may shorten lifetime. For
example, metal migration failures in CD4049/4050
chips increase exponentially with temperature. This
may be life limiting for the AACS (Attitude and Articulation
Control Subsystem) and CDS (Command Data Subsystem).
Introduction of the "hide" maneuvers increases tem-
perature cycling of solder joints somewhat, but the
total estimated fatigue life usage is only about 20%,
every 2 cycles. This means the total fatigue life
consumed by the end of cycle 6 (i.e. 1994), including
ground testing, is in the 80 to 90% range.
Analysis of the Magellan environment for these components,
using results of accelerated life tests by Galileo,
indicates that there is a high probability of failure
after 1994. A second analysis equates higher Magellan
flight temperatures with additional flight hours. By
1994, 5 years of actual flight extrapolates to an
effective life time of over 14 years. Without "hide"
maneuvers it would be 22 years.
b. Gyro: While performance of gyro B-2 is no longer
sufficient for mapping, it can be used for control in
certain fault protection modes. Prior to the problem
with B-2, the four gyros provided triple redundancy in
the X and Y axis and double redundancy in Z. For fault
protection, this same level of redundancy remains. For
mapping, double redundancy still remains in all axes.
The gyro problem represents additional fault protection
software development which is underway and additional
operations complexity.
c. Star Scanner: The star scanner remains sensitive to
solar protons (Type A) and shedding of particles during
spacecraft turns (Type B). However, the two software filters
implemented in AACS during cruise and careful star
selection have greatly reduced the impact, in particular,
in orbit with Venus as another light source.
The on-board filters in most cases reject spurious
interrupts during star scans, but occasionally an
incorrect attitude update occurs which causes mis-
pointing of the high gain antenna and some loss of
mapping data, on the order of few orbits.
The star scanner problem represents additional
operations complexity in correcting the attitude
error. Three incorrect updates have occurred in
mapping since start up on 15 September 1990.
d. X-Band transmitter shutdown: Occasional spacecraft X-
band transmitter shutdowns are a design idiosyncrasy.
Two shutdowns have occurred since start of mapping
resulting in loss of 37 minutes of radar data.
This problem represents additional operations com-
plexity involving coordinated Deep Space Tracking
Network and spacecraft team operations.
e. Solar panel oscillation: This problem, a result
of a control software error with large Sun incidence
angle on the solar panels, has been fixed by disabling
close loop Sun sensor control of solar panel tracking
during mapping. Instead, control is performed using
on-board Sun ephemeris knowledge.
This problem represents minimal additional operations
complexity due to extra commanding.
f. Attitude Control Subsystem Memory B intermittent
stuck address bit: Presently, the bit is unstuck
and Memory-B can be made operational if needed. A
stuck bit detector is under development and an in-
terim version is available today. The final version
will be available for uplinking in January 1991. In
using Memory-B, if Memory-A fails, the detector would
detect a stuck bit and safe the spacecraft.
In addition to this failure detector, a long term fix
is being developed to work around the memory affected
by the stuck bit (2 to 4 K words). Extra memory space
is being generated by stripping out unused code, i.e.
launch, VOI and certain fault protection code. The
current estimate of available memory is 5 K out of 32 K
words total. This fix is estimated to be available by
the end of September 1991.
This problem represents significant additional soft-
ware development which is underway and additional
operations complexity.
g. Attitude Control Subsystem Runaway Program
Execution (RPE): This problem has occurred three
times since VOI on 16 and 21 August and on 15 November.
Address words are corrupted either in the address cir-
cuits or in the input/output interfaces. Each incident
has resulted in loss of signal, except that communication
was lost for only 40 minutes the last time.
Prior to this last incident, flight software modi-
fications were implemented which effectively reset
the computer upon corruption and were successfully
demonstrated during this last incident. Also, in the
long term fix for the Memory-B stuck bit problem, ad-
ditional protection against RPE is being incorporated.
This problem represents significant software development
which is underway and additional operations complexity.
h. Tape Storage: During cruise, excessive bit errors
were initially detected in engineering telemetry play-
back on track 2 of tape recorder A. During playback
of radar data in September 1990, this problem began to
manifest itself at the higher radar data rate on track
2 of tape recorder A. The error rate on track 2 grew
exponentially until track 4 on tape recorder A was sub-
stituted. Again, as with track 2, the error rate on
track 4 increased exponentially over a period of a month
until track 3 was substituted for track 4. Trsed
with tracks 2, 4, or 3 did not exhibit the worsening error
rate until it was used with track 3. Now the error rates
for both tracks 1 and 3 are becoming progressively worse.
Tape recorder B, two tracks of which have been used in
tandem with tape recorder A to prevent data loss during
tape reversals, has not exhibited any problem. Use of
this recorder in a single tape recorder strategy will be
implemented on 22 December 1990. With this strategy, 20-
30 KM gaps will occur three times in each mapping pass
during tape reversals. A five track strategy, using one
track from tape recorder A to buffer tape reversals may
be implemented in early 1991, depending on its eventual
health.
This problem represents additional flight and ground
software development and operations complexity.
17. Spacecraft Survivability Summary:
a. Spacecraft problems and their impacts.
2. Three conclusions can be drawn from this summary chart:
1. The spacecraft system design has proven
to be resilient to problems.
2. We are not finished with software development
as we thought we would be after VOI. More
development has become necessary.
3. Operations have become more complex due to
problems which at times has severely taxed
the team's strength.
b. AACS computer problems, a major threat to spacecraft
survival and a major operations load shortly
after VOI (Venus Orbit Insertion), appears to have subsided.
However, with incomplete understanding, predicting the
future impact of this problem is difficult,
especially in subsequent hotter Extended Mission
cycles. This problem appears to be noise induced
and will probably occur again. However, present and
future flight software modifications greatly reduce
the impact. At this time, these problems do not
appear mission threatening.
c. In cycle 1 and subsequent cycles with superior con-
junctions (odd numbered cycles), the thermal problem
is mitigated by high gain antenna shading. However,
steps needed to keep subsystems cooler in periods near
inferior conjunctions (even numbered cycles) will result
in lesser acquisition of radar data in these cycles.
Some subsystems will still run hotter and will also
experience greater temperature cycling. In the long
run, after 1994, the higher spacecraft temperature may begin
to result in component failures, but this is sufficiently
far enough in the future such that a significant Extended
Mission can be conducted.
d. The star scanner, gyro, and X-Band transmitter shut-
down problems are well in hand at this time and do
not represent threats to spacecraft life.
e. In addition, there is sufficient hydrazine and
solar panel margin to support at least a five year
Extended Mission. An initial estimate of hydrazine
usage to lower and raise periapsis for aerobraking
can be supported by our hydrazine reserves.
f. The two batteries continue to operate satisfactorily
and the integrated load in the mission has been smaller
than anticipated negating the need to do battery re-
conditioning at least through cycle 2. As early as
cycle 3, we may need to do battery reconditioning
or curtail radar operations somewhat at the end of
mapping passes. Also, battery reconditioning eventually
may be needed to keep bus voltage above the fault pro-
tection trip point.
g. The most significant impact to spacecraft life, in terms
of acquiring radar data appears at this time to be
the tape recorder A problem. Even with the high
error rates occurring on tape recorder A almost 100%
of this corrupted data can be recovered with additional
processing.
However, the problem is not understood at this time;
it is not known whether tape recorder A will become
unusable or whether tape recorder B will begin to
manifest the same problem.
Without tape recorders, no radar data can be trans-
mitted to Earth, leaving only gravity mapping data
to be acquired.
Without this current tape recorder problem, tape
recorder life expectancy may still limit the number
of Extended Mission mapping cycles.
It is Odetics experience that the negator spring
fails first, but on the average, actual tape recorder
life has exceeded the life requirements by a factor of
1.5 to 1.7. At the standard mapping usage rate in a
dual tape recorder strategy, the tape recorders could
be expected to be survive at least through cycle 4.
Use of a single tape recorder strategy doubles tape
recorder use and the single tape recorder could be
expected to survive only through at least two cycles.
Limits to tape recorder life may prompt a reduction in
the mapping rate at some time in the Extend Mission to
conserve life to permit mapping over more important
surfaces for more cycles.
18. Scaling down the size of Magellan Operations at sometime in
the Extended Mission will become appropriate after most of
the science data has been acquired or in the event of a
crippling failure. Without major spacecraft or radar failures,
this scaling back could be in the form of a reduced
operations team with a corresponding reduction in the
radar data acquisition rate. Instead of being able to
acquire radar data on each pass, the rate could be scaled
back to, say, one pass per week, for instance.
If the radar interferometry and aerobraking experiments
are feasible and implemented, then any major scaling back
would occur one or two cycles after their execution. If
these experiments are not feasible, then it may be justi-
fiable to scale back after cycle 4. An estimate of the
extent to which the size of the operations team can be
scaled back will be made for POP 91-2.
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
|
| 456.232 | MAGELLAN Update - December 21 | ADVAX::KLAES | All the Universe, or nothing! | Wed Dec 26 1990 12:14 | 35 |
| From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 12/21/90
Date: 21 Dec 90 21:29:03 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
December 21, 1990
The Magellan spacecraft continues to perform nominally, except
for the Tape Recorder A problem. All STARCALS (star calibrations) and
DESATS (desaturations) during the past 24 hours were successful.
The mapping sequence M0356, which will be sent to the spacecraft
later today will shorten the mapping period by 8.6 minutes in order to
accommodate an Earth occultation period of 56 minutes during the
playback. It will also switch the data management strategy to using
only tape recorder B. This strategy will cause three small gaps in
each image swath as tape recorder B switches tracks.
Magellan has now completed 605 mapping orbits and radar data from
about 588 orbits has been successfully received on Earth.
The SAR (Synthetic Aperture Radar) Data Processing Team has
produced 11 standard, 16 special and one temporary image swaths during
the past two days.
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
|
| 456.233 | MAGELLAN Updates - December 14 and 19 | ADVAX::KLAES | All the Universe, or nothing! | Mon Dec 31 1990 17:02 | 140 |
| From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update #2 - 12/14/90
Date: 20 Dec 90 17:14:19 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
RESULTS OF JPL-MARTIN-ODETICS TAPE RECORDER MEETING
December 14, 1990
The Magellan spacecraft recorder is similiar to over 60 machines
flown on weather and other satellites, many of which have as much or
larger usage rates. The Magellan problem, which is data pattern
dependent, appears to be unique. It is manifested by a slip in clock
sync during playback which results in bit slips and flips until sync
is reestablished. The sync slip is involved with the code/decode
process and is due to either wave form distortion or noise interference
in the detection of data transitions. The exact cause is not known at
this time.
Currently, there is no model which can explain the progressively
worsening error rate on first track 2, then track 4, and now, tracks 1
and 3 of tape recorder A. Problems experienced on Hubble and Galileo
recorders do not appear to be relevant to the Magellan problems.
Areas which do NOT appear to be likely sources of the problem:
o Encoding, decoding, bias driver de-jitter buffer, and reproduce
equalization circuitry which are common to all tracks.
o Tape drive servo mechanism.
o Heads being worn.
o Damaged or shedding tape.
o Loss of the DC erase head coarse winding.
o A magnetic record anomaly.
The Magellan problem may have been caused by the launch
environment, since the problem was observed on the engineering data at
low rate, immediately after launch. Also, the VOI (Venus Orbit
Insertion) burn may have been the cause of a temporary improvement in
the low rate performance observed immediately after VOI.
The malfunctioning recorder A was the proto-flight unit and
experienced more severe vibration tests than recorder B. The tape on
recorder B is from a different tape batch than used on recorder A.
However, the tape on recorder A has a very good usage heritage. There
is no evidence of a tape problem.
Starting with the test plan proposed by Odetics, a joint
JPL-MMC-Odetics team will finalize a test plan including tests on the
spacecraft and ground tests using the flight spare. Flight tests will
be carefully scrutinized as to their value as they will most likely
result in some loss of mapping data.
There is no concern at this time in continuing to use recorder B
for mapping. The single tape recorder strategy remains scheduled to
start on December 22.
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 12/19/90
Date: 20 Dec 90 16:27:58 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
December 19, 1990
The Magellan spacecraft continues to be in good health and is
performing nominally. All STARCALS (star calibrations) and DESATS
(desaturations) during the past 24 hours were successful. Of the 552
orbits completed, 535.5 orbits of valid data have been received at
Earth (97.0%).
During the present Occulted Mapping Phase of the mission the weekly
command sequences are sent to the spacecraft on Fridays and the so-called
"tweak" (an update of mapping parameters) is uplinked on Tuesdays.
The radar sensor continues to operate normally. The quality of
playback data from tape recorder tracks A1 and A3 has degraded to the
point that no data from these tracks is being incorporated into the
SAR (Synthetic Aperture Radar) experiment data records. It may be
possible to recover some useful data from these tracks by implementing
special processing of the original data records that is more tolerant
of the kinds of errors that have been observed.
A technical meeting with representatives of Odetics on December
13 ruled out many possible data corruption sources. A series of
tests, using a flight spare recorder and in-flight tests of tape
recorder A in January, will be performed. In the meantime, a data
management strategy using only tape recorder B will be implemented on
December 22.
The SAR Data Processing Team produced 20 standard image swaths,
10 special image swaths and one temporary image during the past two
days. The special image swaths involve reprocessing of the North Pole
area from early orbits to achieve better image resolution that was
enabled by an improved topographic model used by the SAR processor.
E. F. Helin discovered an Amor asteroid 4055 (q=1.2 AU) at
Palomar on February 24, 1985, and submitted the name "Magellan" to the
IAU Committee with the following text:
"Named for the leader of the first expedition to
circum-navigate the Earth and the present highly
successful automated expedition to Venus. Ferdinand
Magellan did not survive the epic voyage of 1519-1522,
but the expedition was a triumph of navigation and
yielded discoveries (including the closest galaxies to
our own) that sustained generations of explorers. The
Magellan spacecraft, unlike its namesake, completed its
voyage in timely fashion and only then met its real
goal, the mapping of the surface of our planetary twin,
a task being carried out with stunning success."
The contract for the 6-foot Venus globe has been placed and the
globe should be delivered to JPL in January.
A special PIO (Public Information Office )Coordination Meeting
was held on December 11 to discuss plans for a Venus poster and the
Magellan "Results" brochure. A single Magellan poster may be produced
in early 1991 for distribution at the time of the Lunar and Planetary
Science Conference in mid-March. The new Magellan brochure will
present the mission results through the first cycle, with publication
in late 1991 (in time for the early 1992 Venus Symposium at Caltech).
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
|
| 456.234 | how do I view these images? | 34823::KAPLOW | Set the WAYBACK machine for 1982 | Fri Jan 04 1991 15:11 | 6 |
| Could someone tell me how to display and/or print the files that
I've copied from pragma::public:[nasa]*.gif and *.img? I guess I'm
ignorant of these file formats. What do I need to do to see these
photos. Thanks for your help.
Bob
|
| 456.235 | | PRAGMA::GRIFFIN | Dave Griffin | Sun Jan 06 1991 02:40 | 14 |
| The .IMG files are DDIF format, and can be viewed with the DECwindows
CDA Viewer (check your DECwindows menu) or the "View/Inter=DECwindows"
command.
The .GIF files can be viewed with one of many GIF viewers around. XGIF
seems to work on many DECwindows systems. A VMS version of XGIF can
be obtained from pragma::toolbox:xgif.exe If it doesn't work for
you, then you'll have to ask around elsewhere.
Also note that there was quite a flurry of similar questions and
answers on this topic in the Astronomy conference. Perusing that
conference may provide additional tidbits.
- dave
|
| 456.236 | MAGELLAN Update - January 2 | ADVAX::KLAES | All the Universe, or nothing! | Mon Jan 07 1991 14:42 | 41 |
| From: yee@trident.arc.nasa.gov (Peter E. Yee)
Newsgroups: sci.space
Subject: Magellan Status for 01/02/91 (Forwarded)
Date: 2 Jan 91 22:06:38 GMT
Sender: usenet@news.arc.nasa.gov (USENET Administration)
Organization: NASA Ames Research Center, Moffett Field, CA
MAGELLAN STATUS REPORT
January 2, 1991
The Magellan spacecraft continues to perform normally. All star
calibrations and momentum wheel desaturations during the holiday
weekend were successful with only small attitude corrections.
All of the commands sent to the spacecraft during the holidays
were performed without incident. A new command sequence will be uplinked
Friday, January 4. It will be a normal weekly mapping command sequence.
The single tape-recorder strategy which was implemented just
before Christmas has been performing as expected. The project shut
off tape recorder A because each of its four tracks was returning
corrupted radar data. With just one tape recorder, each image swath
now has three small gaps in it. The gaps occur when the recorder
switches from one track to another.
A few bad frames still occur with the B-side recorder but the
cause is not known. A project spokesman said, however, that the rate
of bad image frames has dropped and the amount of usable data has
increased significantly with the new strategy.
Magellan this morning completed its 694th mapping orbit of Venus
and data from about 677 orbits has been successfully received on Earth.
The project is currently assessing the number of mapping orbits that
were adversely affected by the tape recorder problem to determine how
many can be recovered by reprocessing.
"America does best when it accepts a challenging mission. We invent
well under pressure. Conversely, we stagnate when caution prevails."
- Edwin "Buzz" Aldrin
|
| 456.237 | MAGELLAN Update - December 27 | ADVAX::KLAES | All the Universe, or nothing! | Mon Jan 07 1991 18:31 | 43 |
| From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 12/27/90
Date: 7 Jan 91 17:07:55 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
[Note: I've just come back from a 2 week vacation in England and will be
posting the various spacecraft status reports from the past two
weeks..................Ron Baalke ]
MAGELLAN STATUS REPORT
December 27, 1990
The Magellan spacecraft continues to be in good health and is
performing nominally. All STARCALS (star calibrations) and DESATS
(desaturations) during the past 24 hours were successful.
During the present Occulted Mapping Phase of the mission the
weekly command sequences are sent to the spacecraft on Fridays and the
so-called "tweak" (an update of mapping parameters) is uplinked on
Tuesdays. However, due to the holidays, the sequences and their
tweaks will be sent to the spacecraft together. The sequence will be
used beginning on December 29 as usual, and the tweak will be made on
Tuesday. The radar sensor continues to operate normally.
We are now using a single tape recorder (DMS B) to meet our
recording requirements. This strategy has been used since early
Saturday (12/28/90) and is performing as expected. We are seeing no
data degradation on DMS B.
We are preparing a DMS A test plan during the holidays that will
describe flight and ground tests needed to isolate the cause of the
degradation of data on DMS A. A formal presentation of the plan will
be made to the Mission Director on 1/9/91.
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
|
| 456.238 | MAGELLAN Updates - December 28 to January 4 | ADVAX::KLAES | All the Universe, or nothing! | Tue Jan 08 1991 15:48 | 140 |
| From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 12/28/90
Date: 7 Jan 91 21:49:47 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
December 28, 1990
The Magellan spacecraft continues to be in good health and performing
nominally through orbit 1142 or 657 mapping orbits. All STARCALS (star
calibrations) and DESATS (desaturations) during the past 24 hours
were successful.
The NAV solution for today's uplink does not meet requirements on radial
position error near the north pole on immediate swaths and the southern end of
delayed swaths. The error near those extremes reaches 200 meters while the
requirement is 150 meters. The errors are attributed to the occultations,
which reduces the quantity of doppler data we can collect, and the orbit being
"edge" on in the plane-of-the-sky.
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 01/02/91
Date: 7 Jan 91 22:20:57 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
January 2, 1991
The Magellan spacecraft continues to perform nominally. All STARCALS
(star calibrations) and DESATS (desaturations) during the holiday weekend were
successful with small attitude updates.
All of the command uploads during the holidays were performed without
incident. The next command upload, M1005, is scheduled for January 4. The
upload designation M1005 tells us: it is (M) a normal weekly mapping command
sequence, followed by the last digit of the year ("1" for 1991), then the day
of year, 005.
The single tape recorder strategy which was implemented just before
Christmas has been performing as expected. Although there have been a few
zero-filled frames, the rate has been extremely low. The amount of usable
radar data has increased significantly.
Magellan has now completed 694 mapping orbits and radar data from about
677 orbits has been successfully received on Earth. We are currently assessing
how many mapping orbits were adversely affected by the tape recorder problem
and how many of those orbits can be recovered by reprocessing. This will be
reported in an upcoming status message.
Ten standard image swaths and one temporary image swath for (orbit #1135)
were processed on the last work-day of 1990.
One final historical note: It was a year ago New Years Eve that Magellan
experienced its first spacecraft safing incident.
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 01/03/91
Date: 7 Jan 91 23:43:30 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
January 3, 1991
The Magellan spacecraft is in good health. All STARCALS (star
calibrations) and DESATS (desaturations) of the past 24 hours were successful
with small attitude updates. Magellan has now completed 701 mapping orbits.
The present mapping sequence shortens the mapping pass by slightly more
than 9 minutes in order to accommodate an Earth occultation of 58.5 minutes
during the playback. This is the maximum period of occultation.
The next command upload, M1005, will have the same timing parameters,
that is, a mapping pass of 28.14 minutes and a playback period shortened by
58.5 minutes.
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 01/04/90
Date: 7 Jan 91 23:48:37 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
January 4, 1991
The Magellan spacecraft is performing nominally. All STARCALS (star
calibrations) and DESATS (desaturations) of the past 24 hours were successful
with small attitude updates.
Today's command load, M1005, will continue the orbit timing parameters of
the past week, that is, a mapping pass of 28.14 minutes and a playback period
shortened by 58.5 minutes. No other commanding is planned through January 7.
The low level of zero-filled frames which has been observed since the
switch to the single tape recorder strategy is caused by the transition from
one track to another. As the tape recorder reaches the end of a tape track,
there is a high probability that it does not coincide with the end of a radar
data frame. If the High Rate Processor observes a partial frame, it fills in
the remaining space with zeros. This does not mean tape recorder B is
experiencing the deterioration seen on on tape recorder A. It is a natural
consequence of the single tape recorder strategy.
January 7 will mark 115 days since radar operations began on September 15.
Subtracting the 15 days when mapping was suspended for Superior Conjunction,
leaves exactly 100 days of radar mapping.
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
|
| 456.239 | PIONEER VENUS Update - January 4 | ADVAX::KLAES | All the Universe, or nothing! | Tue Jan 08 1991 15:49 | 23 |
| From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Pioneer Venus Update - 01/04/91
Date: 7 Jan 91 23:50:09 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
PIONEER VENUS STATUS REPORT
January 4, 1991
An 18 pulse precession maneuver and HGA (High Gain Antenna)
adjustment was successfully executed by the Pioneer Venus spacecraft
on December 28. On January 1, incorrect tracking predicts used at the
70 meter station at Australia caused a 2 hour and 30 minute loss of
telemetry data.
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
|
| 456.240 | MAGELLAN Update - January 8 | ADVAX::KLAES | All the Universe, or nothing! | Tue Jan 08 1991 19:56 | 47 |
| From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 01/08/91
Date: 8 Jan 91 18:15:40 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
January 8, 1991
The Magellan spacecraft is performing nominally. All STARCALS
(star calibrations) and DESATS (desaturations) during the past 24
hours were successful.
There has been a 3 to 5 degree increase in the temperatures of
Bay 7 and one of the propulsion modules. This is expected as the
spacecraft comes out of a period of solar occultation and the time
spent in the shadow of Venus grows shorter. The temperatures are
still well below the alarm limits.
Later today controllers will upload the weekly "tweak," an update
of the radar mapping control parameters. No non-standard commanding
is expected.
The SAR (Synthetic Aperture Radar) Data Processing Team produced
38 standard image swaths during the three workdays last week. This
included two temporary and three special image products. Satisfactory
test image swaths have been produced by the SAR Data Processor from
orbits representing those with the highest bit-error rates from tape
recorder track A2. This is very good news because it indicates that
most, if not all, of the radar data affected by the tape recorder
problem can be processed into usable images.
The second day of the joint meeting between JPL, MMC (Martin
Marietta), and Odetics continued today at JPL on the tape recorder
test planning. It is expected that a cut at both flight and ground
tests by the end of the day will be done. The test objectives are to
determine whether there are any steps needed to be taken to protect
tape recorder-B and whether tape recorder-A can be made usable again.
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
|
| 456.241 | MAGELLAN Update - January 9 | ADVAX::KLAES | All the Universe, or nothing! | Thu Jan 10 1991 16:48 | 41 |
| From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 01/09/91
Date: 9 Jan 91 22:09:28 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
January 9, 1991
The Magellan spacecraft is performing nominally. All STARCALS
(star calibrations) and DESATS (desaturations) during the past 24
hours were successful.
Magellan has now passed over more than 50% of the Venus surface
since radar mapping began on September 15, but due to the Superior
Conjunction gap and other small losses we are still approaching the
point where 50% of the surface has been imaged.
Yesterday controllers sent up the weekly "tweak," an update of
the radar mapping control parameters. As reported earlier, the single
tape recorder strategy currently being used results in three small
gaps as the recorder switches tape tracks during mapping. Due to
variation in the orbital velocity of the spacecraft, the first and
third gaps are about 20 km long, while the gap nearest to periapsis is
about 40 km long. To put this in perspective, the gaps represent less
than 0.6% of each image swath -- about 80 km out of 13,500 km of each
swath.
The gaps do not appear at the same latitude on adjacent swaths
because the start of mapping is delayed by six minutes on all odd
numbered orbits. This offsets the gaps in adjacent swaths by about
2,500 km.
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
|
| 456.242 | MAGELLAN Updates - January 10-11 | ADVAX::KLAES | All the Universe, or nothing! | Mon Jan 14 1991 14:58 | 60 |
| From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 01/10/91
Date: 10 Jan 91 21:09:27 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
January 10, 1991
The Magellan spacecraft is performing nominally. All STARCALS
(star calibrations) and DESATS (desaturations of the reaction wheels)
during the past 24 hours were successful.
Magellan is presently completing its 754th mapping orbit on its
103rd day of radar mapping operations. It takes 243 days for Venus to
turn once under the spacecraft orbit. Each day Magellan completes 7.3
orbits, so by the time we get back over the starting point of our
mapping we will have almost 1,800 image strips.
Even now we have images of more Venus surface than the total land
area of Earth. The two planets are about the same size, but 75% of
Earth is covered by water.
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 01/11/91
Date: 11 Jan 91 17:45:19 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
January 11, 1991
The Magellan spacecraft continues its outstanding performance.
All STARCALS (star calibrations) and DESATS (desaturations) during the
past 24 hours were successful.
Later today, controllers will upload the weekly mapping command
file, M1015, and the updates to radar control parameter and mapping
quaterion files.
The production of full resolution mosaics, called F-MIDRs, is
proceeding on schedule. To date, 51 F-MIDRs have been approved for
distribution by the Project Scientist.
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
|
| 456.243 | PIONEER VENUS Update - January 11 | ADVAX::KLAES | All the Universe, or nothing! | Mon Jan 14 1991 14:59 | 24 |
| From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Pioneer Venus Update - 01/11/91
Date: 11 Jan 91 23:10:18 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
PIONEER VENUS STATUS REPORT
January 11, 1991
On January 8, transmitter glitches at 70 meter Spain station
prevented the transmission of the bit rate command to 1024 bps to the
Pioneer Venus spacecraft. As a result, no data were stored during the
subsequent 6 hour tracking gap. The operational bit rate will be
raised to 341 bps on January 14. The bit rate over 70 meter stations
will be raised to 2048 bps on January 19.
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
|
| 456.244 | MAGELLAN Updates - January 14-16 | ADVAX::KLAES | All the Universe, or nothing! | Thu Jan 17 1991 16:36 | 96 |
| From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 01/14/91
Date: 14 Jan 91 22:23:02 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
January 14, 1991
The Magellan spacecraft and its radar system continue to perform
nominally. All STARCALS (star calibrations) and DESATS (desaturations)
during the weekend were successful with an average attitude update of 0.016
degree.
The spacecraft experienced another spurious shutoff of the high power
transmitter on the morning of January 11 at 9:50 AM PST. It occurred at the
end of a mapping pass, just as the transmitter was powering up to begin
playback. The switch to TWTA-A went smoothly and less than five minutes of
radar data was lost. During the weekend, commands were sent to reset the
fault protection flags.
Also on January 11, the spacecraft controllers detected an error in the
mapping command sequence being sent to the spacecraft later that day. The
error related to a necessary adjustment in the nominal start of the first
orbit of the sequence and the corresponding radar control parameters. This
adjustment occurs only as the spacecraft comes out a period of occulted mapping
and would have executed properly if the initial orbit of the new sequence has
been a delayed orbit.
Various options for correcting the error were reviewed, but there was not
time to build a new command sequence or generate new radar control parameters.
It was decided to continue with the command sequence "as is" with the likely
result of some image loss on the initial orbit of the sequence.
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 01/15/91
Date: 15 Jan 91 19:34:19 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
January 15, 1991
The Magellan spacecraft and its radar system continue to perform
nominally. All STARCALS (star calibrations) and DESATS (desaturations)
during the past 24 hours were successful. As of 10:49 AM (PST), Magellan
has completed 789 mapping orbits.
Later today, the spacecraft controllers will send updates of the radar
control parameter and mapping quaternion files. There will be no "tweak" of
the command sequences.
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 01/16/91
Date: 16 Jan 91 22:30:50 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
January 16, 1991
The Magellan spacecraft and its radar system continue to perform
nominally after 796 mapping orbits. All STARCALS (star calibrations) and
DESATS (desaturations) during the past 24 hours were successful.
No commanding of the spacecraft is planned for today. The spacecraft
telemetry reported some attitude reference alarms last night. There was a
"miscompare" between the Sun sensors in that the location of the Sun as
indicated by the two sensors did not match and/or varied from the reference
value in the on-board computer. This is believed to be an albedo effect of
Venus, and is being studied further.
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
|
| 456.245 | MAGELLAN Update - January 17 | ADVAX::KLAES | All the Universe, or nothing! | Thu Jan 17 1991 22:31 | 44 |
| From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 01/17/91
Date: 17 Jan 91 19:26:04 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
January 17, 1991
The Magellan spacecraft and its radar system continue to perform
nominally after 803 mapping orbits. During the seven STARCALS (star
calibrations) of the past 24 hours, one was unsuccessful due to
rejects of both stars, two were partially successful with one star
reject, and the remaining four were successful. One of the
"successful" attitude updates accepted a false star interrupt,
resulting in an incorrect attitude update of 0.09 degree. The
subsequent STARCAL was successful, correcting the error. The High Gain
Antenna offpoint of less than 0.09 for one orbit is within mission
specs. An increase in star reference rejects has been expected as the
mission geometry changes.
In response to the attitude reference alarms mentioned yesterday,
spacecraft controllers decided to raise the sun loss fault protection
limit from 11 to 30 minutes. The fault protection keeps track of the
amount of time the sensors detect a "miscompare" or abnormal
measurement in "time counts" of 0.53 seconds. If the cumulative time
counts reached the limit, the spacecraft would put itself into a
safing mode. Although the counts remained far below the limit,
controllers felt it was prudent to set the higher time limit. Again,
this is believed to be a Sun geometry problem which occurs
periodically when one Sun sensor picks up the Venus albedo, while the
other views only the Sun.
The weekly mapping command sequence, M1019, and its associated
parameter files will be sent to the spacecraft tomorrow.
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
|
| 456.246 | Image available | PRAGMA::GRIFFIN | Dave Griffin | Fri Jan 18 1991 00:01 | 11 |
| pragma::public:[nasa]mgn_pan_1.gif - GIF format
.img - DDIF greyscale
.info - Information
Image of "pancake domes" from the Magellan orbiter.
Please see prior notes about viewers, etc. Two more voyager images (callisto)
have also been processed.
- dave
|
| 456.247 | Venerean surface becoming more rugged | ADVAX::KLAES | All the Universe, or nothing! | Fri Jan 18 1991 13:25 | 32 |
| From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan article
Date: 17 Jan 91 22:51:14 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
Associated Press -- 1/17/91
"Venus Landscape"
By Lee Siegel
"Some of the most cracked, squeezed and stretched landscape yet seen
on Venus has been captured in pictures made by the Magellan
spacecraft, now halfway through its $744 million mission."
The wire service quotes Annette deCharon, Brown University Magellan
scientist, as saying the new data represents "some of the most
complicated terrain we've seen in Magellan data."
The AP says that the region under study, the Alpha Regio volcanic
highland region of Venus, can be explained by several different
theories including massive floods of erupting lava, squeezing of the
planet's crust, and a third possibility -- linear volcanic eruptions
like those which occur in Earth's mid-oceanic ridges.
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
|
| 456.248 | MAGELLAN Update - January 18 | ADVAX::KLAES | All the Universe, or nothing! | Mon Jan 21 1991 18:44 | 29 |
| From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 01/18/91
Date: 18 Jan 91 22:25:06 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
January 18, 1991
The Magellan spacecraft and its radar system continue to perform
nominally. All of the STARCALS (star calibrations) and DESATS (desatura-
tions) of the past 24 hours were successful with few star rejects.
Yesterday, the Sun loss fault protection limit was raised from 11
to 30 minutes. Later today, the weekly mapping command sequence,
M1019, and its associated parameter files will be sent to the
spacecraft. This is the last occulted mapping sequence in the current
Earth occultation period. It shortens the mapping pass by slightly
less than 7 minutes in order to accommodate an Earth occultation of
about 48 minutes.
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
|
| 456.249 | PIONEER VENUS Update - January 18 | ADVAX::KLAES | All the Universe, or nothing! | Mon Jan 21 1991 18:44 | 25 |
| From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Pioneer Venus Update - 01/18/91
Date: 19 Jan 91 01:17:39 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
PIONEER VENUS STATUS REPORT
January 18, 1991
On January 10, a power failure at the 34 meter station at
Goldstone caused a 1 hour loss of data for the Pioneer Venus
spacecraft. On January 14, CPA (Command Processor Assembly) problems
at the Spain tracking station caused 1 command to be aborted. A
25-pulse precession maneuver has been scheduled for January 19. A
Spin period adjustment will be performed on January 24 following
periapsis.
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
|
| 456.250 | MAGELLAN Update - January 21 | ADVAX::KLAES | All the Universe, or nothing! | Mon Jan 21 1991 18:52 | 33 |
| From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 01/21/91
Date: 21 Jan 91 19:27:43 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
January 21, 1991
The Magellan spacecraft and its radar system continue to perform
nominally. All of the STARCALS (star calibrations) and DESATS
(desaturations) of the past weekend were successful with few star
rejects.
Fluctuations in the downlink signal margin caused mission
controllers to alert the telecommunications experts on the Spacecraft
team. It was suspected to be a DSN (Deep Space Network) station
problem, not a problem with TWTA-B (high power transmitter B), but is
still being studied.
The DSN complexes experienced a variety of communications
problems during the weekend, some of which delayed the lockup with the
spacecraft signal and resulted in data losses ranging from a few
minutes to fifteen minutes, with a total estimated at 47 minutes.
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
|
| 456.251 | MAGELLAN Update - January 22 | ADVAX::KLAES | All the Universe, or nothing! | Wed Jan 23 1991 15:01 | 78 |
| From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 01/22/91
Date: 22 Jan 91 23:46:46 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
January 22, 1991
The Magellan Spacecraft and its radar system continue to perform
nominally, with good STARCALS (star calibrations) and DESATS
(desaturations of the reaction wheels) in the past 24 hours. After
over a month of nearly perfect STARCALS and DESATS there has been a
slight, and expected, increase in star rejects. Spacecraft attitude
has been maintained within mission specs, however.
Recent temporary images strips, using preliminary ephemeris data
and radar data recently received at Goldstone, have shown some one or
two minute gaps. These are now believed to be the result of hardware
problems at the 34 meter Goldstone station.
The Mission Control Team is responsible for 24-hour, real time
monitoring and control of the Magellan mission. Training of the team
members is continuing for two reasons:
o to train personnel new to the team since Venus Orbit
Insertion. Staffing for 24-hour, real time surveillance
has been increased to two people.
o to train all personnel to quickly recognize and respond to
spacecraft or communications anomalies, i.e. the many ways
we can lose the signal.
This training is taking place at JPL, Goldstone, and Denver to
give the controllers direct contact with their DSN (Deep Space Network)
and Spacecraft Team counterparts and the Magellan operational facilities.
The SAR (Synthetic Aperture Radar) Data Processing Team produced
63 F-BIDRs (Full-Resolution Basic Image Data Record) during the 7-day
period ending January 16. This included a standard F-BIDR from orbit
1038 and a temporary F-BIDR from orbit 1275. The temporary F-BIDRs
are produced from data recently received at Goldstone and processed
using preliminary ephemeris data. The purpose of these temporary
products is to achieve timely confirmation that the SAR data
collection process is working properly. The SAR data will be
reprocessed later using final ephemeris data.
The Image Data Processing Team (IDPT) produced 12 new digital
F-MIDR (Full-Resolution Mosaicks) products and one digital Basic
Radiometer Data Record product. These digital products contain data
from several adjacent orbits. The IDPT also produced photographic
transparencies and check-prints corresponding to 26 F-MIDRs.
The 6-foot Venus Globe that is at JPL was installed in the Von
Karman Spacecraft Museum this week. The background surface of Pioneer
Venus and Venera images will be applied to the globe during the next
few weeks by personnel from the United States Geologic Survey (USGS).
A new Magellan exhibit has also been installed in the lobby of
Building 230 at JPL.
A set of twenty released images have been selected for a Magellan
Results Slide Set. This slide set went to the vendor this week.
Cosmonauts Alexander Balandin and Col. Anatoli Solovyov along
with NOVA and Lockheed representatives toured the Magellan Science
Area. The two cosmonauts were visiting NOVA to help highlight an
upcoming NOVA series, "The Soviet Right Stuff," which will be broadcast
in three one-hour segments on February 26, 27 and 28 on the Public
Broadcast System (PBS).
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
|
| 456.252 | MAGELLAN Update - January 23 | ADVAX::KLAES | All the Universe, or nothing! | Wed Jan 23 1991 21:08 | 30 |
| From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 01/23/91
Date: 23 Jan 91 21:01:26 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
January 23, 1991
The Magellan spacecraft and its radar system continue to perform
nominally. Six of the seven STARCALS (star calibrations) in the past
24 hours were successful.
The spacecraft controllers reported a couple of spikes in the
reaction wheel telemetry, indicating brief periods of momentum buildup
near the alarm limits. Corrective commands are planned for later today.
Telemetry from the CDS (Command Data Subsystem) indicated that
spurious command response flags have been set. These occur when the
spacecraft detects incoming commands and none are expected. The cause
of the spurious signals is being investigated.
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
|
| 456.253 | MAGELLAN has mapped 55% of Venus so far | ADVAX::KLAES | All the Universe, or nothing! | Thu Jan 24 1991 15:39 | 87 |
| From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Mapping of Venus (Forwarded)
Date: 24 Jan 91 15:34:40 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN MAPPING OF VENUS PROVIDES SIGNIFICANT NEW KNOWLEDGE
The Magellan spacecraft mapping the surface of Venus with
imaging radar has swept over nearly 55 percent of the planet, an
area comparable on Earth to the distance from Los Angeles to New
Delhi, India. Scientists report that the radar mapping data is
providing significant new knowledge about the surface of Venus
and its atmosphere.
All of the areas mapped show widespread evidence of
volcanism, said Project Scientist Dr. Steve Saunders, along with
evidence of tectonics, the process that produces mountains.
"Venus and Earth are the only planets in our solar system
that have linear mountain belts," he said. But the mountains on
Venus are not deeply eroded by rainfall and running water as are
the mountains on Earth.
Magellan also confirmed the number of Venus impact craters
that scientists had expected to find, judging from their earlier
Earth-based radar data. The smallest impact craters seen so far
on the surface are about 3 miles in diameter, indicating the
dense Venus atmosphere has effectively shielded the surface from
bombardment of smaller asteroids and comets.
There also is evidence that the poisonous, thick atmosphere
of Venus was not formed recently, Saunders said. Surface images
indicate it may be from 400 million to 800 million years old or
even older. The Venus atmosphere is 90 times heavier than that
of Earth and is composed primarily of carbon dioxide with
significant amounts of sulfuric acid at upper levels.
Saunders said scientists see in the images that linear
mountain belts are being pulled apart by gravitational forces on
the planet.
New styles of volcanism have been found and lava channels
hundreds of miles long occur at several places on the plains.
Although lava channels have been found on Earth, none are as long
or as regular as those seen on Venus.
Another new type of volcanism is being referred to by
scientists as "pancake" domes. These structures appear to be up
to 20 miles across and nearly a mile high and form on the plains.
Scientists believe the domes are formed by an outflow of a pasty,
thick lava, similar to silicon-rich lavas on Earth. Volcanic
domes also form on Earth, but they are much smaller and form in
volcanic calderas, Saunders said.
The images also reveal indications of turbulent surface
winds on the planet. The evidence is in the form of wind streaks
in the lee of topographical obstacles, such as the small, low
shield volcanoes on the plains.
"Careful mapping of those wind streaks over the entire
planet may give us meteorological data about circulation of the
atmosphere near the surface," Saunders said.
To date, there have been 118 days of mapping and 973
orbits. A total of 819.6 mapping orbits have been received on
Earth, 45 percent of the planet's surface, Project Manager Tony
Spear said.
Fifteen days of mapping were lost, as expected, to superior
conjunction, the period last November when Earth and Venus were
on opposite sides of the sun and data transmission between the
two planets was impossible.
There have been other losses of data since mapping began
last Sept. 15, due to spacecraft problems and difficulties at the
various Deep Space Network stations, Spear said. But of the area
covered by mapping orbits, only 2.4 percent has been lost.
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
|
| 456.254 | MAGELLAN Update - January 24; news article | ADVAX::KLAES | All the Universe, or nothing! | Thu Jan 24 1991 20:39 | 71 |
| From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 01/24/91
Date: 24 Jan 91 19:59:32 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
January 24, 1991
The Magellan spacecraft and its radar system continue to perform
nominally. All seven STARCALS (star calibrations) in the past 24
hours were successful with no star rejects.
Yesterday, spacecraft controllers performed an extra desaturation
of the reaction wheels (DESAT) to adjust the preload. This was to correct
a condition in which the momentum buildup approached the alarm limits.
The Radar System Engineering Team reports some recurring small
gaps, ranging from 15 to 45 seconds, one gap per orbit, which have
been observed in the recent radar data. An investigation in underway
to determine whether the gaps result from the unique details of the
present single tape recorder mode or problems at the DSN (Deep Space
Network) station. It is definitely not a repeat of the problem which
affected tape recorder "A".
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan article
Date: 24 Jan 91 20:01:24 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
Associated Press -- 1/24/91
"Magellan Venus"
By Lee Siegel
"Volcanic bulges that resemble giant spiders provide more evidence
that Venus' landscape is shaped by huge blobs of molten rock rising
from inside the planet, say Magellan spacecraft scientists."
The AP Los Angeles-based science writer says the bulges, some more
than 100 miles wide, support the theory that Venus' terrain is being
sculpted by "hot spot tectonics" or "blob tectonics."
The story says a similar process created the Hawaiian chain of islands
but the dominant geologic process on Earth is plate tectonics.
The writer says the Venus scientists are calling the features
"arachnoids" because of their resemblance to spiders - a class of
animal called arachnids.
The story cites one Venus scientist, Ellen Stofan, who suggests that
the arachnoids may just be the early stages of what might turn out to
be much larger bulges later.
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |
|
| 456.255 | MAGELLAN Update - January 25 | ADVAX::KLAES | All the Universe, or nothing! | Fri Jan 25 1991 21:10 | 35 |
| From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 01/25/91
Date: 25 Jan 91 21:15:28 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
January 25, 1991
The Magellan spacecraft and its radar system continue to perform
nominally. All STARCALS (star calibrations) and DESATS (desaturations) of
the past 24 hours were successful with four foreground star rejects. The
attitude updates ranged from 0.017 to 0.030 degrees.
The spacecraft controllers are predicting an increase in the number of
background rejects over the next few days due to solar flare activity.
Late today the mapping command sequence M1026 will be sent to the
spacecraft, along with the associated parameter files. This 4-day sequence
returns Magellan to its non-occulted mapping mode. It is for 4 days rather
than 8 days because of the return to the normal Tuesday upload next week.
On Monday, 28 January, commands will be sent to perform the first of
several in-flight tests on the DMS-A (Data Management Subsystem-A). These
tests are designed to determine the cause of the tape recorder deterioration,
with the hope that corrective actions could restore it to partial use.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@mars.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |___ M/S 301-355 | It's 10PM, do you know
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | where your spacecraft is?
|_____|/ |_|/ |_____|/ | We do!
|
| 456.256 | MAGELLAN Update - January 28 | ADVAX::KLAES | All the Universe, or nothing! | Tue Jan 29 1991 14:05 | 40 |
| From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 01/28/91
Date: 28 Jan 91 23:09:50 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
January 28, 1991
The Magellan spacecraft and its radar system continue to perform
nominally. All STARCALS (star calibrations) and DESATS (desaturations) of
the weekend were successful.
On January 25, the mapping command sequence M1026 was sent to the
spacecraft, along with the associated parameter files. The 4-day sequence
returned Magellan to its non-occulted mapping mode. Return to the normal
Tuesday uploads will start with tomorrow's M1030 upload.
Commands were sent up earlier today to perform the first of several
in-flight tests of tape recorder "A". The tests will start at 11:20 AM PST
and will include playback of data from two of the suspect tape tracks at 268
kbps and 115 kbps.
The SAR (Synthetic Aperture Radar) Data Processing Team has processed
standard image strips for orbits up to orbit #1111. Since Magellan is now on
orbit #1370, it means that the team is processing radar image data from 35
days ago, that is, from Christmas Eve. This is because the processing of
standard images must wait for data tapes to be shipped from the DSN (Deep
Space Network) stations in Australia and Spain. During the first 40 days of
mapping these tapes were "expedited" - delivered to JPL by courier - so that
early images could be processed and evaluated quickly.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@mars.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |___ M/S 301-355 | It's 10PM, do you know
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | where your spacecraft is?
|_____|/ |_|/ |_____|/ | We do!
|
| 456.257 | MAGELLAN Update - January 29 | ADVAX::KLAES | All the Universe, or nothing! | Wed Jan 30 1991 14:26 | 34 |
| From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 01/29/91
Date: 29 Jan 91 20:56:29 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
January 29, 1991
The Magellan spacecraft and its radar system are performing
nominally. All STARCALS (star calibrations) and DESATS (desaturations)
since yesterday were successful.
Late today, the mapping command sequence M1030 will be sent to
the spacecraft, along with the associated parameter files.
During the 4-day mapping sequence now being executed, the radar
swath width at the North Pole was increased to 40 km to facilitate
studies of the pole location by the RAND Corporation.
The temperature of spacecraft Battery #1 has gone above the alarm
limit of 20 degrees Celsius several times in the last few days. This
was expected due to the changing sun angle on the orbit and the return
to full mapping passes. Spacecraft controllers are discussing options
for temperature control of the battery.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@mars.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |___ M/S 301-355 | It's 10PM, do you know
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | where your spacecraft is?
|_____|/ |_|/ |_____|/ | We do!
|
| 456.258 | MAGELLAN Update - January 30 | ADVAX::KLAES | All the Universe, or nothing! | Wed Jan 30 1991 18:36 | 28 |
| From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 01/30/91
Date: 30 Jan 91 18:53:40 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
January 30, 1991
The Magellan spacecraft and its radar system are performing
nominally. All STARCALS (star calibrations) and DESATS (desaturation
of the reaction wheels) since yesterday were successful.
The mapping command sequence M1030 was sent last night to the
spacecraft, along with the associated parameter files, and is now
executing. Later today, a command will be sent to reset the battery
heater set points. This will correct the condition mentioned
yesterday where the temperature of spacecraft Battery #1 had gone
above the alarm limit of 20 degrees Celsius several times.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@mars.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |___ M/S 301-355 | It's 10PM, do you know
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | where your spacecraft is?
|_____|/ |_|/ |_____|/ | We do!
|
| 456.259 | MAGELLAN Update - January 30 (#2) | ADVAX::KLAES | All the Universe, or nothing! | Thu Jan 31 1991 15:45 | 60 |
| From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update #2 - 01/30/91
Date: 30 Jan 91 21:41:22 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
January 30, 1991
The spacecraft and the radar system continue to perform nominally
138 days after mapping started on September 15, with 901 mapping
orbits and about 50% of the surface area of Venus captured in images.
In spite of the DMS-A (Data Management Subsystem) deterioration and
intermittent problems at the DSN (Deep Space Network) stations, about
95% of the radar mapping data collected by the spacecraft has been
successfully captured on Earth.
The spacecraft completed its period of apoapsis Earth
occultations and returns to full mapping passes on January 26.
Spacecraft temperatures continue to warm due to changing solar
geometry. An extra reaction wheel desaturation was required on
January 23, when momentum buildup exceeded the preset limits before
an adjustment to the preload could take effect.
On Wednesday, January 23, the Radar System Engineering Team
(RSET) reported an unexpected spike in the radiometer data of orbit
1319, indicating a brightness temperature 125 degrees Celsius higher
than normal for the Venus surface. The spike was also found on orbit
1318. Scientists and spacecraft engineers are analyzing the data to
determine if the high readings were caused by the spacecraft position
relative to the Sun or actual surface features on Venus.
[Perhaps an active volcano? - LK]
The Image Data Processing Team produced the following new data products:
o Six Altimeter Data Records
o One Basic Radiometer Data Record
o Nine Polar Image Data Records
o Two Compressed Basic Image Data Records
o Two Full Resolution Mosaicked Image Data Records (F-MIDRs)
Eighteen additional F-MIDRs were nearly finished and are expected
to be completed this week.
The "Magellan at Venus" report on January 23 featured Dr. Ellen
Stofan, who discussed the arachnoid features on Venus. Ellen will
host today's show on January 30.
The 10 x 12 foot crater farm mosaic recently on display in the
lobby of Building 180 at JPL has been sent to the Maryland Museum of
Science in Baltimore.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@mars.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |___ M/S 301-355 | It's 10PM, do you know
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | where your spacecraft is?
|_____|/ |_|/ |_____|/ | We do!
|
| 456.260 | MAGELLAN Update - January 31; news article | ADVAX::KLAES | All the Universe, or nothing! | Fri Feb 01 1991 14:11 | 76 |
| From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 01/31/91
Date: 31 Jan 91 20:19:38 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
January 31, 1991
The Magellan spacecraft and its radar system are performing
nominally. All STARCALS (star calibrations) and DESATS (desaturations)
since yesterday were successful.
The correction to the battery heater set points has successfully
brought down the battery #1 temperature to the desired range.
Data from tape recorder test #1 is still being analyzed, but
preliminary results indicate that the erase process performs as
expected. Test #2, which will look for deterioration of the tape
itself, has been postponed for a few days. The section of little-used
tape, which engineers wanted to compare to a heavily-used part of the
tape, was found to have been overwritten. Other tests of the flight
tape recorder "A", using specific bit patterns or encoding rules, are
being prepared.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@mars.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |___ M/S 301-355 | It's 10PM, do you know
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | where your spacecraft is?
|_____|/ |_|/ |_____|/ | We do!
From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan article
Date: 31 Jan 91 19:36:28 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
Associated Press -- 1/31/91
"Magellan Venus"
By Lee Siegel
"Intense squeezing, stretching, collapsing and bulging of Venus'
landscape may explain why the planet is marked by an amazing network
of faults and cracks, Magellan spacecraft geologists say."
The Los Angeles-based science writer says the region of Venus' Alpha
highlands is so extensively deformed by geological forces that NASA
was describing it like bread dough which had been kneaded.
The story says the Magellan radar data have revealed extensively
fractured regions, named tesserae after the Greek word for tile, which
cover from 10 to 15 percent of the planet's surface and which contain
criss-crossing faults which may cause "Venusquakes."
The writer says that analysis of the tesserae data so far seems to
indicate the tesserae features may have been subjected to different
forces at different times. Some regions may have been created as
cooler rock in Venus' crust slowly sank deeper into the planet and
thereby created a downward drag that squeezed overlying layers to form
the faults, ridges and valleys.
The story says that molten rock rising from deep inside Venus may have
also created some tesserae by making the landscape bulge upward and
stretch apart.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@mars.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |___ M/S 301-355 | It's 10PM, do you know
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | where your spacecraft is?
|_____|/ |_|/ |_____|/ | We do!
|
| 456.261 | MAGELLAN Updates - February 1 and 4 | ADVAX::KLAES | All the Universe, or nothing! | Tue Feb 05 1991 14:15 | 66 |
| From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 02/01/91
Date: 5 Feb 91 00:54:53 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
February 1, 1991
The Magellan spacecraft and its radar system are performing
nominally. All STARCALS (star calibrations) and DESATS (desaturations)
since yesterday were successful, with attitude updates averaging less
than 0.04 degree.
The battery #1 temperature is now peaking at 18 degrees Celsius,
which is well below the alarm limit. Later today the 1033 "tweak" (a
routine update of the radar mapping sequence and parameters) will be
sent to the spacecraft.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@mars.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |___ M/S 301-355 | It's 10PM, do you know
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | where your spacecraft is?
|_____|/ |_|/ |_____|/ | We do!
From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 02/04/91
Date: 5 Feb 91 00:56:38 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
February 4, 1991
The Magellan spacecraft and its radar system are performing
nominally. All STARCALS (star calibrations) and DESATS (desaturations)
over the weekend were successful. The attitude updates are averaging
about 0.040 degrees since the reference star pair was changed, which is
somewhat larger than earlier update averages but well within specification.
Temperatures of various spacecraft subsystems have been
increasing as the sun angle changes. During the weekend the battery
#1 temperature crept back up to a peak of 20 degrees Celsius. The sun
angle will be perpendicular to the battery compartment today.
Software is being developed to counter the increasing
temperatures, either to "hide" behind the High Gain Antenna or to
alternate sides of the spacecraft exposed to the Sun. The "hide"
maneuvers which will be needed ultimately in cycle 2 will cause a loss
of 10% to 60% of the radar data on each orbit.
The P1033 "tweak" on February 1 (a routine update of the radar
mapping sequence and parameters) was successful. No commanding of the
spacecraft is planned for today.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@mars.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |___ M/S 301-355 | It's 10PM, do you know
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | where your spacecraft is?
|_____|/ |_|/ |_____|/ | We do!
|
| 456.262 | MAGELLAN Update - February 5 | ADVAX::KLAES | All the Universe, or nothing! | Tue Feb 05 1991 19:44 | 31 |
| From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 02/05/91
Date: 5 Feb 91 20:13:41 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
February 5, 1991
The Magellan spacecraft and its radar system are performing
nominally. All STARCALS (star calibrations) and DESATS (desaturations)
of the past 24 hours were successful with only one star reject.
The spacecraft is now in its 944th mapping orbit and is
approaching the point where 50% of the surface has been imaged.
Temperatures of various spacecraft subsystems have been increasing as
the sun angle changes. Yesterday, the battery #1 temperature peaked at
21 degrees Celsius. The sun angle will be perpendicular to the
battery compartment today.
Late today the M1037 command sequence will be sent to the
spacecraft with the associated parameters.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@mars.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |___ M/S 301-355 | It's 10PM, do you know
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | where your spacecraft is?
|_____|/ |_|/ |_____|/ | We do!
|
| 456.263 | MAGELLAN Update - February 6 | ADVAX::KLAES | All the Universe, or nothing! | Wed Feb 06 1991 19:14 | 29 |
| From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 02/06/91
Date: 6 Feb 91 19:20:28 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
February 6, 1991
The Magellan spacecraft and its radar system are performing
nominally. All STARCALS (star calibrations) and DESATS (desaturations)
of the past 24 hours were successful with attitude updates averaging
0.048 degree.
Temperatures of several spacecraft subsystems have been near their
alarm limits, and mission controllers are monitoring them closely.
Last night, the M1037 command sequence was successfully sent to
the spacecraft, with the associated radar control parameter and
mapping quaternion files, and began execution this morning.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@mars.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |___ M/S 301-355 | It's 10PM, do you know
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | where your spacecraft is?
|_____|/ |_|/ |_____|/ | We do!
|
| 456.264 | MAGELLAN Update - February 6 (#2) | ADVAX::KLAES | All the Universe, or nothing! | Thu Feb 07 1991 18:56 | 42 |
| From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update #2 - 02/06/91
Date: 6 Feb 91 20:53:10 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
February 6, 1991
The Magellan spacecraft and its radar system are performing
normally. All star calibrations and momentum wheel desaturations of
the past 24 hours were successful with very slight attitude updates.
Temperatures of several spacecraft subsystems have been near
their alarm limits because the spacecraft is now getting more direct
sunlight that it did earlier in the mission. The temperatures are
being monitored closely and plans are being made to turn the spacecraft
periodically to get all parts of it in the shade at various times.
The new command sequence was successfully sent to the spacecraft
late Tuesday, and it began execution today.
Project Manager Tony Spear announced a new program to
systematically remove sources of commanding errors while making the
uplink system run faster and more efficiently. Spear said the program
is "simply a desire to do better. We want to learn from, and correct,
our mistakes."
Since launch, he said, the project has made 18 command errors in
199,406 commands, about 9 command errors per 100,000. He defined a
command error as an inappropriate and unplanned spacecraft event
caused by a command. Benefits of the program should include lower
mission operating costs, he said.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@mars.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |___ M/S 301-355 | It's 10PM, do you know
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | where your spacecraft is?
|_____|/ |_|/ |_____|/ | We do!
|
| 456.265 | MAGELLAN Update - February 7 | ADVAX::KLAES | All the Universe, or nothing! | Thu Feb 07 1991 19:34 | 56 |
| From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 02/07/91
Date: 7 Feb 91 20:10:16 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
February 7, 1991
The Magellan spacecraft is performing as expected. All STARCALS
(star calibrations) and DESATS (desaturations) of the past 24 hours
were successful. The spacecraft is now in its 958th mapping orbit and
the radar system performance is nominal.
Temperatures of spacecraft subsystems continue to be the focus of
mission controllers. The geometry of Magellan's orbit about Venus and
its position relative to the sun during mapping and playback were
expected to produce higher temperatures during the this part of the
prime mission and extending into the extended mission cycle.
Anticipating these higher temperatures, two strategies were developed.
One strategy, called "Flip Flop," controls the temperatures by
turning the opposite side of the spacecraft to the sun during the
second playback period. The timing of the mapping pass and playback
periods would be unchanged. The disadvantage of this approach is that
spacecraft parts would be subjected to more thermal cycles. If used,
the Flip Flop strategy would be implemented starting with the April 9
command load, and continuing until April 30, then switching to the
second strategy.
The second strategy, called "Two Hide," controls spacecraft
temperatures by including two periods in each orbit when the equipment
bays would "hide" in the shade of the High Gain Antenna. This
strategy would require a shortening of the mapping pass and playback
periods similar to the strategy during occulted mapping. This
strategy would be used from the April 30 command load until the July
23 load.
Using both strategies is a severe challenge to the sequence
planners since command sequences are started at least six weeks before
the date of the command upload. At the Spacecraft Technical
Interchange Meeting in Denver last week, predicted spacecraft
temperatures for this transition period were presented, and the pros
and cons of the two strategies discussed. Based on this discussion,
the Mission Director, Jim Scott, decided to stay with the nominal
mapping sequence thru April 16, then go directly to the "Two Hide"
strategy for the mapping loads for the next 14 weeks.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@mars.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |___ M/S 301-355 | It's 10PM, do you know
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | where your spacecraft is?
|_____|/ |_|/ |_____|/ | We do!
|
| 456.266 | MAGELLAN Update - February 8 | ADVAX::KLAES | All the Universe, or nothing! | Tue Feb 12 1991 13:31 | 38 |
| From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 02/08/91
Date: 8 Feb 91 21:57:47 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
February 8, 1991
The Magellan spacecraft is performing as expected. The seven
STARCALS (star calibrations) and two DESATS (desaturations) of the
past 24 hours were successful. The attitude updates averaged 0.0465
degree. The spacecraft is now in its 965th mapping orbit and the
radar system performance is nominal.
Later today, the routine "tweak" of the mapping command sequence
will be sent to the spacecraft. The Sun Sensor Unit reference loss
and miscompare count reached an alarm limit briefly yesterday. This
is believed to be a repeat of the albedo effects of Venus experienced
by the spacecraft a couple of weeks ago, but the Spacecraft Team is
monitoring it along with the temperatures.
Battery #1 is still peaking at 22 degrees Celsius, with its alarm
limit set at 25 degrees. If the limit is reached, on-board fault
protection would reset relays to prevent battery heaters from turning
on. (Actually, the battery heaters are not operating now because the
thermal cycle stays high enough not to activate the heaters.) A
command to raise the limit to 28 degrees is tested and "on the shelf"
should controllers decide it is necessary.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@mars.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |___ M/S 301-355 | It's 10PM, do you know
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | where your spacecraft is?
|_____|/ |_|/ |_____|/ | We do!
|
| 456.267 | MAGELLAN Update - February 11 | ADVAX::KLAES | All the Universe, or nothing! | Tue Feb 12 1991 14:34 | 34 |
| From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 02/11/91
Date: 11 Feb 91 22:49:33 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
February 11, 1991
The Magellan spacecraft is performing nominally. All STARCALS
(star calibrations) and DESATS (desaturatons of the reaction wheels)
of the past weekend were successful. Magellan is now in its 988th
mapping orbit and the radar system performance is nominal.
The temperatures are continuing a warming trend, not leveling off
as was expected. Battery #1 is now peaking at 25.1 degrees Celsius,
so its alarm limit was reset to 28 degrees. The battery heaters are
not operating now because the thermal cycle does not drop low enough
to activate the heaters.
Later today, an update to the Radar Control Parameter File will
be sent to the spacecraft. The regular weekly command sequence,
M1044, will be sent late tomorrow. Commands to implement Test #3 of
the on-board tape recorder "A" are planned for uploading on Wednesday,
February 13.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@mars.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab | Is it mind over matter,
___| | | | |__) |/ | | |___ M/S 301-355 | or matter over mind?
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | Never mind.
|_____|/ |_|/ |_____|/ | It doesn't matter.
|
| 456.268 | MAGELLAN Update - February 12 | ADVAX::KLAES | All the Universe, or nothing! | Tue Feb 12 1991 21:40 | 63 |
| From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 02/12/91
Date: 12 Feb 91 20:55:59 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
February 12, 1991
On Monday, February 11, Magellan engineers noted that the
temperatures of the spacecraft battery compartment have continued to
increase during the mapping portion of each orbit, reaching a maximum
of 25 degrees Celsius. This continued, slow increase is occurring even
though the incidence angle of the Sun on the battery compartment is
decreasing. Two explanations have been postulated:
o The battery compartment is being illuminated by specular
reflection of sunlight from the solar panels; or
o The exterior of the battery compartment is turning darker
with exposure to the Sun, increasing the percentage of
the Sun's heat absorbed.
The battery temperature alarm limit, designed to protect against
a failed-on battery heater, is currently set at 28 degrees. At 32
degrees, spacecraft fault protection would disconnect the overheated
battery from the spacecraft electrical power system, and relying only
on the backup battery.
In order to keep the battery temperatures within acceptable
limits, the Project has decided to shorten the period of mapping on
alternate orbits by turning the spacecraft to point the High Gain
Antenna toward Earth ten minutes earlier than the nominal mapping
orbit. This decrease in mapping time will cause a 10 minute loss of
radar date on "delayed swath" orbits, when the radar data is collected
further south, and the decrease in mapping time will therefore
decrease the southerly extent of the mapping coverage from 78 to 52
degrees south latitude. Immediate swath orbits are not affected by
this early turn to Earth point.
Various approaches to controlling the spacecraft temperatures
were analyzed. Several were discarded because of difficulties in
preparing the command sequences or in processing the resulting radar
image data. This method of decreasing heating was chosen because it
can be implemented quickly without special modifications to the normal
command sequence. The changes in orbit timing will be carefully
verified in the Systems Verification Laboratory, then transmitted to
the spacecraft today to take effect tomorrow.
The shortened mapping pass will be reassessed on February 14 for
possible increase or decrease based on the observed temperatures. The
heating is expected to be alleviated in about two weeks when the
spacecraft again begins to pass through the shadow of Venus during its
mapping period.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@mars.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab | Is it mind over matter,
___| | | | |__) |/ | | |___ M/S 301-355 | or matter over mind?
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | Never mind.
|_____|/ |_|/ |_____|/ | It doesn't matter.
|
| 456.269 | Keeping MAGELLAN from overheating | ADVAX::KLAES | All the Universe, or nothing! | Wed Feb 13 1991 13:50 | 49 |
| From: clarinews@clarinet.com
Newsgroups: clari.tw.space
Subject: Magellan heating triggers changes
Date: 12 Feb 91 22:16:08 GMT
PASADENA, Calif. (UPI) -- NASA's Magellan probe was ordered
Tuesday to spend 35 minutes less each day mapping the surface of
Venus, allowing the spacecraft to reorient itself to keep sunlight
from causing critical batteries to overheat, officials said.
Engineers at the Jet Propulsion Laboratory said shortening
Magellan's mapping time was a temporary measure that should only be
needed for the next 17 days or so. In the meantime, mapping runs over
Venus's southern hemisphere will be shortened by 10 minutes every
other orbit.
Magellan, launched from the shuttle Atlantis in May 1989, went
into orbit around Venus on Aug. 10 last year. After overcoming a
variety of minor glitches, the spacecraft began mapping the cloudy
planet's hidden surface Sept. 15 using a radar system that produces
photo-like images.
Magellan operates in a highly elliptical three-hour, 15-minute
orbit around Venus, one tilted 86 degrees to the equator with a low
point of about 170 miles and a high point of about 5,000 miles.
Radar mapping takes place as the probe travels through the
low- altitude part of each orbit. After each 37-minute mapping run,
Magellan re-orients itself, points its dish antenna toward Earth and
beams recorded data back to JPL. The probe then aims its antenna at
Venus and makes another mapping pass.
Magellan currently is exposed to full sunlight throughout each
orbit, causing the temperature of the spacecraft's battery compartment
to rise toward allowable limits.
To prevent the batteries from getting too hot, Magellan was
ordered Tuesday to point its dish antenna back toward Earth 10 minutes
early each mapping pass, putting the battery compartment in the shade
provided by the antenna.
Project manager Tony Spear said the shortened mapping time
will decrease coverage of Venus's southern hemisphere by a small
amount over the next 17 days or so.
So far, more than 55 percent of Venus's surface has been
``imaged'' by Magellan's radar. The goal of the mission is to map up
to 90 percent of the planet's surface with unprecedented clarity.
|
| 456.270 | MAGELLAN Update - February 13 | ADVAX::KLAES | All the Universe, or nothing! | Wed Feb 13 1991 17:23 | 36 |
| From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 02/13/91
Date: 13 Feb 91 17:11:31 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
February 13, 1991
The Magellan spacecraft is performing nominally. All STARCALS
(star calibrations) and DESATS (desaturations) in the past 24 hours
were successful. Magellan is now in mapping orbit #1002 and the radar
system performance is nominal.
Last night's upload of command sequence M1044 implemented a
decision to shorten alternate radar mapping passes by 10 minutes. By
an early turn of the spacecraft toward Earth, controllers expect to
reduce the peak temperatures. The timing change went into effect with
orbit #1486.
The improvement in spacecraft temperatures was quickly apparent.
Where Battery #1 had peaked at 27.2 degrees Celsius on the last full
mapping pass, it peaked at 25.3 degrees on orbit #1486; then 24.1
degrees on orbit #1487. The transmitter dropped two degrees and the
gyros were down one degree. So, the strategy of shortening the
mapping pass has apparently worked, and the Spacecraft Team (along
with the rest of the Project) can breathe a sigh of relief.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@mars.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab | Is it mind over matter,
___| | | | |__) |/ | | |___ M/S 301-355 | or matter over mind?
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | Never mind.
|_____|/ |_|/ |_____|/ | It doesn't matter.
|
| 456.271 | MAGELLAN Update - February 14 | ADVAX::KLAES | All the Universe, or nothing! | Thu Feb 14 1991 17:26 | 33 |
| From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 02/14/91
Date: 14 Feb 91 17:58:40 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
February 14, 1991
The Magellan spacecraft is performing nominally. All STARCALS
(star calibrations) and DESATS (desaturations) in the past 24 hours
were successful. The attitude updates averaged 0.049 degree. Magellan
is now in mapping orbit #1010 and the radar system performance is nominal.
The spacecraft temperatures have stabilized at an acceptable
level. Where Battery #1 had peaked at 27.2 degrees Celsius on the last
full mapping pass, it now peaks at 23.5 degrees. The transmitter is
at 53 degrees and the gyroscopes at 67 degrees.
The strategy of shortening the mapping pass by ten minutes cuts
26 degrees of latitude off the southern end of the delayed image
swaths. Over the 17 to 21 days that this this strategy will be used
for temperature control, the loss of image area will be less than 1%
of the Venus surface.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@mars.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab | Is it mind over matter,
___| | | | |__) |/ | | |___ M/S 301-355 | or matter over mind?
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | Never mind.
|_____|/ |_|/ |_____|/ | It doesn't matter.
|
| 456.272 | Active volcanoes on Venus? | ADVAX::KLAES | All the Universe, or nothing! | Thu Feb 14 1991 21:30 | 39 |
| From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan article
Date: 14 Feb 91 22:43:27 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
Associated Press -- 2/14/91
"Venus Volcanoes"
By Lee Siegel
"Some volcanoes on Venus erupt explosively and spew ash skyward,
unlike the planet's typical volcanoes, which gently produce lava
flows, the Magellan spacecraft has found."
The AP Los Angeles science writer says that although Magellan hasn't
yet caught a Venutian volcano in the act of spewing forth material, it
has found signs, in the radar imagery it is sending back, of Venus'
landscape that strongly suggest earlier volcanic blasts. The story
says these appear as ash deposits in various regions.
The report notes that Venus lacks water which would erode away the
surface to acquire the ash-strewn look, and the winds on the planet
are sluggish enough so that there is no wind-caused erosion either.
Given these two predicates, the story says the Magellan scientific
team has concluded that what they are seeing are, in fact, the ash
remains of volcanic eruptions.
The story says that in some cases, the ash appears to be deposited as
much as six miles from its probable source. The report says that, as
of now, Magellan has mapped slightly over half of the surface of Venus.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@mars.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab | Is it mind over matter,
___| | | | |__) |/ | | |___ M/S 301-355 | or matter over mind?
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | Never mind.
|_____|/ |_|/ |_____|/ | It doesn't matter.
|
| 456.273 | MAGELLAN Update - February 15 | ADVAX::KLAES | All the Universe, or nothing! | Sun Feb 17 1991 19:17 | 34 |
| From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 02/15/91
Date: 16 Feb 91 03:15:04 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
February 15, 1991
The Magellan spacecraft is performing nominally. Six of seven
STARCALS (star calibrations) in the past 24 hours were successful, one
partially successful.
The spacecraft temperatures remained stable, but some slightly
higher than reported yesterday. For example, Battery #1 was reaching
a peak of 23.5 degrees C, it now peaks at 23.9 degrees C. The transmitter
is at 52.5 degrees C and the gyroscopes at 67.3 and 67.8 degrees C.
At the Mission Director's meeting this morning, the results of
the temperature control strategy will be assessed. It seems likely
that the shortened mapping orbits will continue until the spacecraft
enters the next period of periapsis occultations in about two weeks.
There will be discussion, however, of adjusting the timing of the turn
away from mapping to balance the temperature concerns against science
return.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@mars.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab | Is it mind over matter,
___| | | | |__) |/ | | |___ M/S 301-355 | or matter over mind?
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | Never mind.
|_____|/ |_|/ |_____|/ | It doesn't matter.
|
| 456.274 | MAGELLAN Update - February 18 | ADVAX::KLAES | All the Universe, or nothing! | Tue Feb 19 1991 19:02 | 28 |
| From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 02/18/91
Date: 19 Feb 91 03:44:35 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
February 18, 1991
The Magellan spacecraft is performing nominally. All STARCALS
(star calibrations) and DESATS (desaturations) during the weekend were
successful.
The spacecraft temperatures remained stable, some slightly lower.
Battery #1 is peaking at 24.8 degrees C. The gyroscopes are at 68.5
degrees C. The gyros are in a compartment which is still picking up
some reflected sunlight from the solar panels and will probably be the
last area to see temperatures drop as we move away from the period of
maximum solar heating during the mapping pass.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@mars.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab | Is it mind over matter,
___| | | | |__) |/ | | |___ M/S 301-355 | or matter over mind?
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | Never mind.
|_____|/ |_|/ |_____|/ | It doesn't matter.
|
| 456.275 | MAGELLAN Update - February 19 | ADVAX::KLAES | All the Universe, or nothing! | Wed Feb 20 1991 13:53 | 40 |
| From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 02/19/91
Date: 20 Feb 91 02:26:26 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
February 19, 1991
The Magellan spacecraft is performing nominally. All STARCALS
(star calibrations) and DESATS (desaturations) during the weekend were
successful.
Later today the weekly upload of the mapping command sequences
with the associated radar control parameter and mapping quaternion
files will be performed. This sequence will continue the 10 minute
shortening of the delayed mapping swaths. It will also include
commands to offpoint the solar panels by 90 degrees at the beginning
and end of each mapping pass. This is intended to reduce the thermal
effects of sunlight reflecting off the solar panels on to the
spacecraft bus.
The spacecraft controllers plan to monitor the temperatures
closely for the first three orbits of the new sequence. If the
offpointing of solar panels does not produce a leveling or drop in the
critical temperatures, additional steps will be taken to keep the
gyros below 70 degrees C.
Among the options available are (1) turning off the back-up
Attitude Reference Unit (ARU) electronics, and (2) shortening the
mapping passes by an additional 5 minutes.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@mars.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab | Is it mind over matter,
___| | | | |__) |/ | | |___ M/S 301-355 | or matter over mind?
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | Never mind.
|_____|/ |_|/ |_____|/ | It doesn't matter.
|
| 456.276 | MAGELLAN Update - February 20 | ADVAX::KLAES | All the Universe, or nothing! | Thu Feb 21 1991 18:26 | 48 |
| From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 02/20/91
Date: 21 Feb 91 02:20:20 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
February 20, 1991
The Magellan spacecraft is performing nominally. Five of the
STARCALS (star calibrations) during the past 24 hours were successful,
two partial. The partially successful attitude updates which had both
foreground and background rejects did not impact performance.
The M1051 mapping command sequence with its associated radar
control parameter and mapping quaternion files was successfully sent
to the spacecraft and began execution about 4:00 AM (PST) this
morning. This sequence continues the delayed mapping swaths that are
10 minutes shorter. This strategy permits flight controllers to turn
the spacecraft away from the direct sunlight so it can cool to some
extent. Currently, and for about the next two weeks, the spacecraft
is in sunlight at all times in its orbit and flight controllers are
taking steps to assure it doesn't reach high temperature alarm limits.
Orbit #1539, which started at 7:12 AM, was the first orbit to
include the offpoint of the solar panels by 90 degrees at the
beginning and end of each mapping pass. Spacecraft controllers have
verified that the offpoint was correctly executed and are monitoring
the temperatures closely to see if the offpoint reduces the thermal
effects of sunlight reflecting off the solar panels onto to the
spacecraft bus. It will take several hours to assess the results of
this strategy.
It is also noted that Venus is now very bright in the sky for
about an hour after sunset close to the horizon. The evening star, as
the planet has been called for centuries, has two NASA spacecraft in
orbit around it, Magellan and Pioneer Venus Orbiter. Radio
communication between Magellan and Earth is constant and the Pioneer
orbiter is still very active.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@mars.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab | Is it mind over matter,
___| | | | |__) |/ | | |___ M/S 301-355 | or matter over mind?
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | Never mind.
|_____|/ |_|/ |_____|/ | It doesn't matter.
|
| 456.277 | Using solar panels to cool MAGELLAN | ADVAX::KLAES | All the Universe, or nothing! | Thu Feb 21 1991 18:26 | 64 |
| From: clarinews@clarinet.com
Newsgroups: clari.tw.space
Subject: Magellan probe still running hot
Date: 20 Feb 91 21:52:15 GMT
PASADENA, Calif. (UPI) -- The Magellan space probe's two solar
panels were repositioned Wednesday to keep reflected sunlight off the
Venus radar mapper in an ongoing effort to keep the craft from overheating.
The spacecraft recently was ordered to shorten the time spent
photographing Venus each orbit with a cloud-piercing radar system to
keep critical batteries out of direct sunlight. The change was made
after engineers noticed temperatures in the battery compartment were
approaching design limits.
But officials at the Jet Propulsion Laboratory said Wednesday
the spacecraft was still running hot and that additional measures were
necessary.
``We are still in a situation where we are shortening our
mapping swath by 10 minutes each orbit,'' said Magellan engineer Steve
Wall. ``We're also doing one other thing. The solar panels ... are
reflecting part of the sunlight back onto the equipment bay and adding
another source of heat.
``We changed the angle of the solar panels so we get less
reflection off the solar panels. That reflection now goes out into
space. The price we pay for that is that we are now collecting a
little less power.''
He said ``if, as the week goes on, that doesn't give us enough
relief from the heat, then we may have to shorten our mapping swath a
little bit more.''
Magellan dropped into orbit around Venus Aug. 10, 15 months
after launch from the space shuttle Atlantis on May 4, 1989.
The 2 1/2-ton solar-powered satellite was designed to ``see''
through the clouds that perpetually blanket Venus by bouncing radar
beams off the planet's surface. Extensive computer processing on Earth
can convert such radar data into photo-like images showing surface
features as small as a football field.
Magellan was placed in a highly elliptical three-hour, nine-
minute orbit around Venus, one tilted 86 degrees to the equator with a
low point of about 170 miles and a high point of about 5,000 miles.
As the probe travels through the low-altitude part of each
orbit, its 12-foot dish antenna fires radar pulses at the ground,
``illuminating'' a 15.5-mile-wide, 9,900-mile-long swath.
After each 37.2-minute mapping run, Magellan re-orients
itself, points the antenna toward Earth and beams the recorded radar
data back to the Jet Propulsion Laboratory in Pasadena. The probe then
swings back around and aims its antenna at Venus for another mapping run.
Because of the positions of Earth, Venus and the sun, Magellan
currently is exposed to continuous sunlight.
By re-orienting the spacecraft to point toward Earth 10
minutes early each orbit, the battery compartment ends up in the shade
of the probe. Re-orienting the solar panels is also expected to
improve cooling.
|
| 456.278 | MAGELLAN Updates - February 21-22 | ADVAX::KLAES | All the Universe, or nothing! | Sun Feb 24 1991 17:53 | 69 |
| From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 02/21/91
Date: 23 Feb 91 03:46:27 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
February 21, 1991
The Magellan spacecraft and its radar system are performing nominally.
The offpoint of the solar panels for about 5 minutes at the
beginning and end of each mapping pass has reduced the thermal effects
of sunlight reflecting off the solar panels on to the spacecraft bus.
The gyro temperatures have leveled off at 68.8 degree C and Battery #1
is peaking at about 23.4 degrees C. The resulting depth of battery
discharge is about 12 percent.
A decision was made yesterday afternoon to continue the solar
panel offpoint and shortened mapping strategy through the remainder of
mapping sequence M1051. That is, the earliest change to this strategy
would be in the M1058 command sequence next Tuesday.
On February 28 (next Thursday), Magellan begins a period of
periapsis occultations, when a portion of the low end of each orbit
passes through the shadow of Venus. This will help to cool the
spacecraft as the length of time in the shadow increases.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@mars.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab | Is it mind over matter,
___| | | | |__) |/ | | |___ M/S 301-355 | or matter over mind?
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | Never mind.
|_____|/ |_|/ |_____|/ | It doesn't matter.
From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 02/22/91
Date: 23 Feb 91 04:11:45 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
February 22, 1991
The Magellan spacecraft and its radar system are performing
nominally. Six of the seven STARCALS (star calibrations) were
successful, with attitude updates averaging 0.05 degree.
Most of the spacecraft temperatures have leveled off, but the
gyroscope temperatures are again showing a slow increase. The current
rate of increase is 1/3 of a degree (Centigrade) per day, with a peak
at 69.2 degrees C.
Yesterday, the upload of specific data patterns for Test #3 of
Flight Tape Recorder "A" was accomplished. The playback of the test
patterns will be performed on Wednesday, February 27.
Later today, the T1054 command sequence update (or "Tweak") and
associated parameter files will be sent to Magellan.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@mars.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab | Is it mind over matter,
___| | | | |__) |/ | | |___ M/S 301-355 | or matter over mind?
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | Never mind.
|_____|/ |_|/ |_____|/ | It doesn't matter.
|
| 456.279 | MAGELLAN maps Aphrodite Terra | ADVAX::KLAES | All the Universe, or nothing! | Sun Feb 24 1991 17:54 | 77 |
| From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Maps Aphrodite Terra
Date: 23 Feb 91 03:48:12 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN COMPLETES MAPPING OF VENUS HIGHLAND REGION
At least four competing theories about the nature of Aphrodite
Terra, a continent-sized highland on Venus, are being tested by new
Magellan data, a scientist at NASA's Jet Propulsion Laboratory,
Pasadena, Calif., said Thursday.
The Magellan spacecraft, which began imaging the surface of the
planet last September 15, has mapped more than 58 percent of Venus.
Aphrodite Terra, the largest of the highland regions on Venus,
extends nearly two-thirds of the way around the planet. Magellan has
completed mapping of the region, but the process of producing image
mosaics lags behind actual data acquisition, said Project Scientist
Dr. Steve Saunders. Still, scientists have been able to study radar
images of the western portion of Aphrodite, called Ovda Regio.
Earlier data produced by the Pioneer Venus Radar Mapper indicated
that the regional topography may be similar to Earth's continents,
Saunders said. The various theories are based on the Pioneer data and
other earlier radar imagery, as well as topography and gravity data.
"All of the leading proponents of competing ideas for the nature
of Venusian continents are part of the Magellan science team and this
leads to lively debates during the science analysis meetings," he said.
The first hypothesis is the "ancient continent" model which holds
that Aphrodite formed from lighter rock that crystallized early and
literally floated on the dense mantle of Venus. There are similar
formations on Earth and on the Moon.
A second theory is called the "spreading ridge" model. This
compares the topography of Aphrodite to that of mid-ocean ridges on
Earth where new crust is being formed as the continents drift apart.
Another hypothesis advocates the "hot spot" model which says the
equatorial highlands were pushed up by hot spots similar to the ones
that lie beneath the island of Hawaii. Hot spots are regions of
mantle that tend to rise, producing broad domes frequently resulting
in huge volcanoes.
The fourth hypothesis is that western Aphrodite is a region of
"mantle downwelling." That means a downwelling plume of colder, more
dense mantle material causes the surface crust to compress and
thicken. The thicker region stands higher than the surroundings.
"The study of Aphrodite will be extremely important for
understanding the origin of continental regions of Venus," Saunders
said, "and may help us better understand our own planet."
Referring to the predicted models for the formation of Aphrodite,
he added, "Someone should have predicted that none of the early
hypotheses would be easily confirmed. Nature, once again,
demonstrates that she is far more imaginative than we, and has
provided a surface full of surprises."
Magellan's primary mission cycle of 243 days, one Venus rotation,
ends May 15, at which time more than 80 percent of the surface will
have been mapped.
JPL manages the Magellan mission for NASA's Office of Space
Science and Applications.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@mars.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab | Is it mind over matter,
___| | | | |__) |/ | | |___ M/S 301-355 | or matter over mind?
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | Never mind.
|_____|/ |_|/ |_____|/ | It doesn't matter.
|
| 456.280 | MAGELLAN Update - February 25 | ADVAX::KLAES | All the Universe, or nothing! | Tue Feb 26 1991 18:35 | 35 |
| From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 02/25/91
Date: 25 Feb 91 19:45:50 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
February 25, 1992
The Magellan spacecraft and its radar system are performing
nominally. All 22 STARCALS (star calibrations) and 6 DESATS
(desaturation of the reaction wheels) during the weekend were
successful, with attitude updates averaging 0.056 degree. As of noon
today (PST), Magellan will have completed 1201 orbits of Venus, with
1027.5 orbits of radar mapping data returned to Earth.
The gyroscope temperatures are reaching a peak of 69.6 degrees C
and are being watched closely. The alarm limit is set at 70 degrees C.
Tomorrow the M1058 command sequence will be sent to the
spacecraft. It will include the solar panel offpoint and 10 minute
early turn from mapping in order to maintain spacecraft temperatures
at acceptable levels. It will also contain the commands to playback
the specific bit patterns which were recorded on the DMS-A (Data
Management Subsystem) on February 21. This playback is Test #3 of the
flight recorder "A".
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@mars.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab | Is it mind over matter,
___| | | | |__) |/ | | |___ M/S 301-355 | or matter over mind?
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | Never mind.
|_____|/ |_|/ |_____|/ | It doesn't matter.
|
| 456.281 | MAGELLAN Update - February 26 | ADVAX::KLAES | All the Universe, or nothing! | Tue Feb 26 1991 20:43 | 31 |
| From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 02/26/91
Date: 26 Feb 91 21:29:26 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
February 26, 1991
The Magellan spacecraft and its radar system are performing
nominally. All STARCALS (star calibrations) and DESATS (desaturations)
during the past 24 hours were successful.
The gyroscopes' temperatures appear to be leveling off, with a
peak at 69.8 degrees C. The alarm limit is set at 70 degrees C.
Later today, the M1058 command sequence will be sent to the
spacecraft. It will include the solar panel offpoint and 10 minute
early turn from mapping in order to maintain spacecraft temperatures
at acceptable levels. It will also contain DMS-A (Data Management
Subsystem) Test #3 which plays back stored data patterns which were
recorded on February 21.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@mars.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab | Is it mind over matter,
___| | | | |__) |/ | | |___ M/S 301-355 | or matter over mind?
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | Never mind.
|_____|/ |_|/ |_____|/ | It doesn't matter.
|
| 456.282 | MAGELLAN Update - February 27 | ADVAX::KLAES | All the Universe, or nothing! | Thu Feb 28 1991 17:02 | 36 |
| From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 02/27/91
Date: 28 Feb 91 03:14:33 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
February 27, 1991
The Magellan spacecraft and its radar system are performing nominally.
All STARCALS (star calibrations) and DESATS (desaturations) during the past
24 hours were successful with attitude updates averaging 0.056 deg.
The M1058 command sequence was sent to the spacecraft and is presently
executing. It includes the solar panel offpoint and 10 minute early turn
from mapping in order to maintain spacecraft temperatures at acceptable levels.
DMS-A (Data Management Subsystem) Test #3, the playback of stored
data patterns, will start near the end of orbit #1591 this morning and
continue through orbit #1602 tomorrow evening. The gyroscope temperatures
have been declining, with a peak at 68 degrees C.
Spacecraft controllers believe that they are already seeing the effects
of solar occultation as measured by the solar panel output. Navigation
predicted that the spacecraft would first encounter the shadow of Venus early
tomorrow morning, so we are probably observing the effects of Venus'
atmosphere. The effects are seen for as much as six minute per orbit.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@mars.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab | Is it mind over matter,
___| | | | |__) |/ | | |___ M/S 301-355 | or matter over mind?
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | Never mind.
|_____|/ |_|/ |_____|/ | It doesn't matter.
|
| 456.283 | MAGELLAN Update - February 28 | ADVAX::KLAES | All the Universe, or nothing! | Fri Mar 01 1991 14:07 | 34 |
| From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 02/28/91
Date: 1 Mar 91 01:07:20 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
February 28, 1991
The Magellan spacecraft and its radar system are performing
nominally. All STARCALS (star calibrations) and DESATS (desaturation
of the reaction wheels) during the past 24 hours were successful.
The command sequence presently executing includes the solar panel
offpoint and 10 minute early turn from mapping in order to maintain
spacecraft temperatures at acceptable levels.
DMS-A (Data Management Subsystem) Test #3, the playback of tape
recorded data patterns, started yesterday and will continue through
orbit #1602 this evening.
Spacecraft controllers are continuing to see the effects of solar
occultation, as measured by the solar panel output and declining
temperatures. A decision is expected tomorrow to resume the full 37.2
minute mapping passes as part of tomorrow's command sequence update.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@mars.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab | Is it mind over matter,
___| | | | |__) |/ | | |___ M/S 301-355 | or matter over mind?
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | Never mind.
|_____|/ |_|/ |_____|/ | It doesn't matter.
|
| 456.284 | MAGELLAN Update - March 1 | ADVAX::KLAES | All the Universe, or nothing! | Mon Mar 04 1991 17:21 | 43 |
| From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 03/01/91
Date: 2 Mar 91 01:08:36 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
March 1, 1991
The Magellan spacecraft and its radar system are performing
nominally. All STARCALS (star calibrations) and DESATS (desaturations)
during the past 24 hours were successful, with the attitude updates
averaging less than 0.04 degree.
The command sequence update being sent to the spacecraft later
today will remove the 10 minute early turn from mapping and restore
the full 37 minute mapping swaths. DMS-A (Data Management Subsystem)
Test #3, the playback of tape recorded data patterns, has been
completed and the playbacks are being studied.
The spacecraft is now in a period of periapsis occultations where
the orbit passes through the shadow of Venus during the low part of
the orbit. This results in added cooling for the spacecraft components.
When the periapsis occultations end in mid-April, however, a temperature
control strategy will have to be implemented again.
The strategy which will be used is called "Two Hide," denoting
two 8 to 12 minute segments in each orbit when the spacecraft is
positioned to hide the electronic compartments in the shade of the
High Gain Antenna. It is expected that this strategy will require a
period of four weeks at the end of the primary mission. Since the
time in hiding will deduct from the mapping pass, the strategy will
result in image losses amounting to about 2% of the surface area of
Venus.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@mars.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab | Is it mind over matter,
___| | | | |__) |/ | | |___ M/S 301-355 | or matter over mind?
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | Never mind.
|_____|/ |_|/ |_____|/ | It doesn't matter.
|
| 456.285 | Computer-generated film of Venus surface | ADVAX::KLAES | All the Universe, or nothing! | Wed Mar 06 1991 15:40 | 204 |
| From: clarinews@clarinet.com (WILLIAM HARWOOD, UPI Science Writer)
Newsgroups: clari.tw.space,clari.tw.science
Subject: Magellan movie released
Date: 5 Mar 91 21:25:55 GMT
The Magellan Venus radar probe has yet to find signs of rigid
continental ``plates'' like those making up Earth's surface, but
scientists said Tuesday they are increasingly confident about eventually
understanding the tortured structure of the hellish planet.
At a televised briefing held at the Jet Propulsion Laboratory in
Pasadena, Calif., project officials also unveiled a short but
breathtaking computer video based on Magellan data that simulates a
high-speed dash over two towering Venusian volcanoes, several impact
craters and a deep ``rift'' valley.
And Laurence Soderblom, a geologist with the U.S. Geological Survey
in Flagstaff, Ariz., said frequently observed ``splotches'' associated
in many cases with impact craters may provide clues about the
composition and history of Venus's surface.
As for the behavior of any continent-sized ``plates'' on the surface
of Venus, ``we haven't identified anything that looks like Earth-like
plate tectonics,'' said project scientist Stephen Saunders.
``The plates appear to be perhaps a little squishier than on Earth,''
he said. ``On Earth, we have a few extremely rigid plates and all the
activity takes place along their margins.
``Up to now we've seen kind of a hodgepodge of tectonics and
volcanism and not been able to see enough of an area to reveal a
pattern,'' he said. ``But as we're looking at larger and larger areas,
we're able to see patterns emerging.''
Magellan dropped into orbit around Venus Aug. 10, 1990, 15 months
after launch from the space shuttle Atlantis on May 4, 1989. The solar-
powered spacecraft uses radar beams instead of visible light to ``see''
through the thick clouds that block the planet's surface from view.
The resulting data can be processed by powerful computers on Earth to
create photograph-quality images of Venus's surface, showing features as
small as 350 feet across -- about the size of a football field -- and 10
times better than the best previous data.
Despite problems with a data recorder and a computer unit that
occasionally knocks the craft out of contact with Earth -- the fourth and
most recent such incident happened Monday night -- Magellan is expected
to photograph 82 percent of Venus's surface by May 15, the end of its
initial 243-day mapping run.
If the spacecraft remains healthy, and if NASA gets another $169
million from Congress, the mission will be extended to include coverage
of the planet's south pole region and to fill in the gaps left from the
primary mission.
A high priority of the extended mission is looking for signs of
active volcanism.
``I'm positive that at some place on the planet there will be active
volcanism,'' Saunders said.
In many ways, Venus is Earth's twin in the solar system. Both planets
are roughly similar in size and mass, both are relatively close to the
sun and both probably were almost identical very early in the history of
the solar system.
But somewhere along the way, the environments of Venus and Earth
diverged, leaving Venus the victim of a runaway greenhouse effect in
which the solar radiation trapped by the planet's thick cloud cover
produces surface temperatures of 900 degrees Fahrenheit -- hot enough to
melt lead -- and pressures comparable to those found at an ocean depth of
2,500 to 3,000 feet.
``The entire surface appears to have been reset in the last half a
billion years or so,'' Soderblom said. ``What's suggested is that every
half a billion years or so ... major eruptive events occur that
completely obliterate the cratering record.
``So we don't see ... farther back in time than a billion years or
so. In fact we probably see farther back in places on the Earth than we
do on Venus.''
Soderblom said the density of Venus's thick atmosphere shields the
planet from smaller impacts and affects the way larger impact craters
are formed, giving scientists a tool for studying the composition of the
surface.
``The atmosphere of Venus is quite thick,'' he said. ``Think about
the case of firing a pistol into an aquarium. The effect on the (bullet)
is to decelerate it. The other effect is to accelerate the atmosphere.
``So there's a timing going on here in which an impact occurs
and the ejecta, which is a conical sheet of material that comes out of
the crater, will take several seconds to form. Soon thereafter, the
atmosphere arrives with a giant blast having been accelerated by the
passage of the body.''
That column of air then smashes into the cloud of material thrown up
by the initial impact, which has the result of ``folding that conical
sheet down onto itself.''
The appearance of the resulting splotch can provide valuable insights
into the nature of the material ejected by the impact.
From: clarinews@clarinet.com (WILLIAM HARWOOD, UPI Science Writer)
Newsgroups: clari.tw.space,clari.tw.science,clari.news.top
Subject: Magellan stripping mystery from Venus
Date: 6 Mar 91 06:14:54 GMT
Lava from planet-wide volcanism apparently resurfaces vast areas of
Venus every 500 million years or so, and while direct evidence of active
volcanoes has yet to be seen, scientists are confident NASA's Magellan
probe will find such proof in the months ahead.
``The entire surface appears to have been reset in the last half a
billion years or so,'' Laurence Soderblom, a geologist with the U.S.
Geological Survey, said Tuesday during a briefing at the Jet Propulsion
Laboratory in Pasadena, Calif.
``What's suggested is that every half a billion years or so ... major
eruptive events occur that completely obliterate the (impact) cratering
record. So we don't see ... farther back in time than a billion years or
so. In fact, we probably see farther back in places on the Earth than we
do on Venus.''
As for whether Venus is volcanically active to this day, Magellan
project scientist Stephen Saunders said he is ``positive that at some
place on the planet there will be active volcanism.''
But the flood of data from the Magellan radar mapping probe has not
revealed any evidence for the kind of slow-moving continent-sized
``plates'' that make up Earth's surface.
``We haven't identified anything that looks like Earth-like plate
tectonics,'' Saunders said. ``The plates appear to be perhaps a little
squishier than on Earth. On Earth, we have a few extremely rigid plates
and all the activity takes place along their margins.
``Up to now we've seen kind of a hodgepodge of tectonics and
volcanism and not been able to see enough of an area to reveal a
pattern,'' he said. ``But as we're looking at larger and larger areas,
we're able to see patterns emerging.''
The Magellan probe, launched from the shuttle Atlantis on May 4,
1989, slipped into orbit around Venus on Aug. 19, 1990. The solar-
powered spacecraft uses radar beams instead of visible light to ``see''
through the thick clouds that block the planet's surface from view.
The resulting data can be processed by computers on Earth to create
photograph-like images of Venus's surface, showing features as small as
350 feet across -- about the size of a football field -- and 10 times
better than the best previous data.
The data also can be used to make dramatic movies. Project
officials unveiled a breathtaking computer video Tuesday that
simulates a high-speed dash over two towering Venusian volcanoes --
whether they are active or not is unknown -- several impact craters
and a deep ``rift'' valley.
Despite problems with a data recorder and a computer unit that
occasionally knocks the craft out of contact with Earth -- the fourth and
most recent such incident happened Monday night -- Magellan is expected
to photograph 82 percent of Venus's surface by May 15, the end of its
initial 243-day mapping run.
The National Aeronautics and Space Administration intends to continue
mapping beyond that point, however, to include coverage of the planet's
south pole region and to fill in the gaps left from the primary mission.
In many ways, Venus is Earth's twin in the solar system. Both planets
are roughly similar in size and mass; both are relatively close to the
sun, and both probably were almost identical very early in the history
of the solar system.
But somewhere along the way, the environments of Venus and Earth
diverged, leaving Venus the victim of a runaway greenhouse effect in
which the solar radiation trapped by the planet's thick cloud cover
produces surface temperatures of 900 degrees Fahrenheit -- hot enough to
melt lead -- and pressures comparable to those found at an ocean depth of
2,500 to 3,000 feet.
Soderblom said the density of Venus's thick atmosphere shields the
planet from smaller impacts and affects the way larger impact craters
are formed, giving scientists a tool for studying the composition of the
surface.
``The atmosphere of Venus is quite thick,'' he said. ``Think about
the case of firing a pistol into an aquarium. The effect on the (bullet)
is to decelerate it. The other effect is to accelerate the atmosphere.
``So there's a timing going on here in which an impact occurs
and the ejecta, which is a conical sheet of material that comes out of
the crater, will take several seconds to form. Soon thereafter, the
atmosphere arrives with a giant blast having been accelerated by the
passage of the body.''
That column of air then smashes into the cloud of material
thrown up by the initial impact, which has the result of ``folding
that conical sheet down onto itself.''
The appearance of the resulting ``splotch'' can provide valuable
insights into the nature of the surface material ejected by the impact.
|
| 456.286 | MAGELLAN Updates - March 4-8; news article | ADVAX::KLAES | All the Universe, or nothing! | Mon Mar 11 1991 20:14 | 197 |
| Date: 8 Mar 91 19:13:16 GMT
From: snorkelwacker.mit.edu!usc!elroy.jpl.nasa.gov!jato!mars.jpl.nasa.gov!
baalke@bloom-beacon.mit.edu (Ron Baalke)
Subject: Magellan Update - 03/04/91
MAGELLAN STATUS REPORT
March 4, 1991
Full mapping was resumed on March 2 when the 10-minute early turn
from mapping attitude to playback attitude was removed. Thermal
conditions had improved late last week due to periapsis solar
occultation season commencement, allowing the removal of the maneuver.
Temperatures continue to decline after a short-lived rise over
the weekend as a result of the early maneuver removal. The gyroscopes
increased about 1/2 degrees C before continuing to cool. Current
peaks are about 67.7 degrees C. All spacecraft component temperatures
remain within established limits.
Star scanner filter activity continues to be moderate. Three
star scans were partially successful since March 1; the remaining
nineteen were fully successful.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@mars.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab | Is it mind over matter,
___| | | | |__) |/ | | |___ M/S 301-355 | or matter over mind?
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | Never mind.
|_____|/ |_|/ |_____|/ | It doesn't matter.
Date: 8 Mar 91 22:39:46 GMT
From: elroy.jpl.nasa.gov!jato!mars.jpl.nasa.gov!baalke@decwrl.dec.com
(Ron Baalke)
Subject: Magellan Update - 03/05/91
MAGELLAN STATUS REPORT
March 5, 1991
At about 5:47 PM (PST) on March 4, the fourth in a series of
attitude computer interrupts occurred when the spacecraft had turned
away for a star calibration. The result was that a series of fault
protection actions occurred during the time the spacecraft was turned
away and a relatively large buildup in pointing error occurred. This
in turn resulted in the loss of signal for about 2 1/2 hours.
It was assumed that Magellan had suffered another heart beat
timer loss incident, and was 3 to 4 degrees off Earth point. No
spacecraft emergency was declared. At about 8:20 PM (PST) the S-band
signal was reacquired. Commanding then began to place the spacecraft
back to the primary gyro's which provide more pointing accuracy.
Commands were then sent to regain the desired pointing accuracy.
During this whole time the sequence on-board the spacecraft
continued to function. By 8:00 AM (PST) today a successful star
calibration showed that a pointing accuracy of 0.04 degrees had been
achieved and the spacecraft was back to a good mapping posture.
As a result of this latest incident, about 3 1/2 orbits of
mapping data has been lost and an additional orbit (Orbit 1634) will
have about a 1 degree pointing error.
Temperatures during the incident were elevated in several parts
of the spacecraft, but not to dangerous levels. Temperatures have now
returned to those observed prior to the incident.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@mars.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab | Is it mind over matter,
___| | | | |__) |/ | | |___ M/S 301-355 | or matter over mind?
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | Never mind.
|_____|/ |_|/ |_____|/ | It doesn't matter.
Date: 8 Mar 91 22:43:48 GMT
From: elroy.jpl.nasa.gov!jato!mars.jpl.nasa.gov!baalke@decwrl.dec.com
(Ron Baalke)
Subject: Magellan Update - 03/06/91
MAGELLAN STATUS REPORT
March 6, 1991
The Magellan spacecraft has been performing nominally since the
brief anomaly on Monday evening. Five of the seven STARCALS during
the past 24 hours were successful, two partially successful due to
rejects of the star Alpha Tau.
Yesterday, the command sequence M1065 was sent to the spacecraft
and it began execution this morning on orbit #1641. This sequence
includes memory readouts of both the A and B side of the Attitude and
Articulation Control Systems (AACS-A & B).
The spacecraft continues in a period of periapsis occultations
where the low part of the orbit passes through the shadow of Venus.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@mars.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab | Is it mind over matter,
___| | | | |__) |/ | | |___ M/S 301-355 | or matter over mind?
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | Never mind.
|_____|/ |_|/ |_____|/ | It doesn't matter.
Date: 9 Mar 91 00:57:52 GMT
From: elroy.jpl.nasa.gov!jato!mars.jpl.nasa.gov!baalke@decwrl.dec.com
(Ron Baalke)
Subject: Magellan Update - 03/07/91
MAGELLAN STATUS REPORT
March 7, 1991
The Magellan spacecraft is performing nominally. All STARCALS
(star calibrations) and DESATS (desaturations) during the past 24
hours were successful.
Spacecraft controllers have been monitoring the temperatures of
the reaction wheels which seemed to be climbing slightly. The
temperature has now stabilized at 53.5 degrees C.
The DMS-A (Data Management Subsystem-A) Test #3, which consisted
of playback of specific bit patterns from the various tape tracks,
produced puzzling results on Track #1 at 268 kbps. Engineers are now
considering repeating the Track #1 playback to try to replicate the
results.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@mars.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab | Is it mind over matter,
___| | | | |__) |/ | | |___ M/S 301-355 | or matter over mind?
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | Never mind.
|_____|/ |_|/ |_____|/ | It doesn't matter.
Date: 9 Mar 91 01:05:06 GMT
From: elroy.jpl.nasa.gov!jato!mars.jpl.nasa.gov!baalke@decwrl.dec.com
(Ron Baalke)
Subject: Magellan Update - 03/08/91
MAGELLAN STATUS REPORT
March 8, 1991
The Magellan spacecraft is performing nominally. All STARCALS
(star calibraions) and DESATS (desaturations) during the past 24 hours
were successful.
The spacecraft has now performed 160 days of radar mapping at
Venus. The represents 1172 mapping orbits, covering about 237 degrees
of global longitude or 66% of the distance around the planet.
Magellan will complete its first mapping cycle on May 15, 1991.
At the end of the first mapping cycle, the Magellan Project
expects to have high resolution images of more than 80% of the surface
of Venus. Some of the non-imaged area was expected, such as the South
Polar gap and the portions missed during Superior Conjunction or
Apoapsis Occultation. Other gaps were the result of spacecraft or
telecommunications problems.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@mars.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab | Is it mind over matter,
___| | | | |__) |/ | | |___ M/S 301-355 | or matter over mind?
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | Never mind.
|_____|/ |_|/ |_____|/ | It doesn't matter.
Date: 8 Mar 91 22:50:01 GMT
From: rex!wuarchive!usc!elroy.jpl.nasa.gov!jato!mars.jpl.nasa.gov!baalke@g.ms.
uky.edu (Ron Baalke)
Subject: Magellan article
Los Angeles Times -- 3/6/91
"Magellan Data from Venus is Vast, Complex"
By Lee Dye
"The Magellan spacecraft has responded to more than 80,000 commands
and has sent back more bits of data from Venus than was collected
during the entire missions of the Voyager, Viking, and Mariner
spacecraft, scientists said Tuesday."
The Times reports that despite images which are telling scientists
more about Venus and its hot, smoldering surface than the lunar
missions told of the Moon, planetary scientists are still disagreeing
over the powerful forces which are molding the tortured surface of Venus.
The article says the volume of data is so staggering and the geologic
processes so complex that the scientific team are struggling to
understand some of the fundamental forces at work on Earth's twin.
The story tells of images which feature surface effects described as
a folding process similar to that here on Earth which created the
mountain ranges of California. Other images, according to the story,
depict blotches and smudges on the surface which seem to indicate
activity ongoing even today.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@mars.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab | Is it mind over matter,
___| | | | |__) |/ | | |___ M/S 301-355 | or matter over mind?
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | Never mind.
|_____|/ |_|/ |_____|/ | It doesn't matter.
|
| 456.287 | Naming Venus surface features after women | ADVAX::KLAES | All the Universe, or nothing! | Mon Mar 11 1991 20:16 | 181 |
| Date: 8 Mar 91 20:34:16 GMT
From: usenet@ames.arc.nasa.gov (Peter E. Yee)
Subject: Names of notable women to be proposed for Venus features (Forwarded)
Paula Cleggett-Haleim
Headquarters, Washington, D.C. March 8, 1991
(Phone: 202/453-1547)
Jim Doyle
Jet Propulsion Laboratory, Pasadena, Calif.
(Phone: 818/354-5011)
RELEASE: 91-38
NAMES OF NOTABLE WOMEN TO BE PROPOSED FOR VENUS FEATURES
Scientists of NASA's Magellan Project, in association with the
U.S. Geological Survey, are inviting the public to propose names of
notable women for the many impact craters and large volcanic vents
being discovered on Venus by the Magellan spacecraft's imaging radar.
"We want everyone, especially students, to share in the
adventure of discovery," said Magellan Project Scientist Dr. Steve
Saunders. He said that the impact craters on Venus are some of the
most beautiful features in the solar system. They form somewhat
randomly in time and space when an asteroid or very large comet
collides with Venus' surface.
"The flower-like symmetry of impact craters evidences the
enormous energy of these infrequent events," he said. "A modest
20-mile-diameter crater represents more energy than is contained in
all the arsenals on Earth."
Names sent to the Magellan Project offices at NASA's Jet
Propulsion Laboratory will be compiled for the Working Group for
Planetary System Nomenclature, a committee of the International
Astronomical Union (IAU). The IAU gives final approval to names for
bodies in the solar system.
Because the IAU meets only every 3 years and its next meeting
is in July 1991, names newly proposed for Venusian features will not
be considered until the following meeting in 1994. But names proposed
this year, if accepted as provisional by the nomenclature committee,
may be used on published maps and in articles, pending final approval
by the IAU.
Scientists at the U.S. Geological Survey's Flagstaff, Ariz.,
field office said they expect names for 4000 or more features on Venus
are likely to be required in the coming decade. Of those features, at
least 900 are expected to be impact craters. Cratersand volcanic calderas,
called "paterae," on Venus are named for notable, actual women.
Indeed, all features on Venus are named for women, with only
three exceptions. They are Maxwell Montes, named years ago for early
radar pioneer James Maxwell, and Alpha Regio and Beta Regio.
"The mapping of Venus is unique in the history of
cartography," said USGS cartographers Ray Batson and Joel Russell.
"Never has so much territory been discovered and mapped in so short a
period of time."
The process of naming features on Venus began in the 1960s
with early radar images taken from Earth. It continued through radar
mapping spacecraft expeditions of the United States and Soviet Union.
But, they said, the Magellan mission is resolving features 25
times smaller than those mapped previously and its radar data will
cover an area nearly equivalent to that of the continents and the
ocean floors on Earth.
Many features on Venus, by international agreement, are named
for goddesses of ancient religions and cultures. But craters and
volcanic calderas or vents, the paterae, are named for actual women.
There are certain stipulations, however. For example, women
must have been deceased for at least 3 years and must have been in
some way notable or worthy of the honor.
Names of military or political figures of the 19th and 20th
Centuries are specifically forbidden under rules of the IAU, as are
the names of persons prominent in any of the six main living religions.
Names of a specific national significance also are not allowed.
When the name is submitted, her birth and death years and a
one or two sentence written rationale for the honor should be given,
along with a reference book citation, if available.
The Magellan project members ask that submissions be sent to:
Venus Names
Magellan Project Office
Mail Stop 230-201
Jet Propulsion Laboratory
4800 Oak Grove Dr.
Pasadena, Calif. 91109
From: clarinews@clarinet.com (ROB STEIN, UPI Science Editor)
Newsgroups: clari.tw.space
Subject: Venusian craters, volcanic vents to be named after women
Date: 8 Mar 91 17:48:58 GMT
WASHINGTON (UPI) -- Craters, volcanic vents and other
formations recently found on the tortured surface of Venus will be
named after notable women from Earth, and the public can propose
candidates, officials announced Friday.
NASA and the U.S. Geological Survey are compiling possible
names for features identified by the Magellan space probe, which is
mapping the mysterious planet named after the Roman goddess of love
and beauty, officials said.
A list of some 700 names has already been compiled, including
American writer Gertrude Stein, French writer Simone de Beauvoir,
American anthropologist Margaret Mead and Aurelia, Julius Caesar's
mother, officials said.
Names will be needed for at least 4,000 formations, including
500 large craters formed when asteroids or large comets slammed into
the planet. The craters are considered some of the most beautiful
features seen in the solar system.
``They have flower-like symmetry and are very well
preserved,'' said Magellan project scientist Steve Saunders from
NASA's Jet Propulsion Laboratory in Pasadena, Calif., which is
controlling the space probe.
Women who can have features named after them must have been
dead for at least three years and must have ``been in some way notable
or worthy of the honor,'' NASA said.
Military or political figures from the 19th and 20th centuries
are barred, as are names of persons prominent in any of the six main
currently practiced religions and names of specific national
significance, officials said.
Proposed names can be sent to the Magellan project offices at
the Jet Propulsion Laboratory and compiled for the 12-member Working
Group for Planetary System Nomenclature, a committee of the
International Astronomical Union.
Because the IAU only meets every three years, the proposed
names will not be formally considered until 1994. But names proposed
this year can be accepted provisionally by the committee and used on
maps pending final approval.
The IAU calls for many features of Venus to be named for
goddesses of ancient religions and cultures and craters and volcanic
vents to be named for actual women.
The naming of features on Venus began in the 1960s when early
radar images of the planet were taken from Earth and continued after
subsequent more detailed images were produced by spacecraft from the
United States and Soviet Union.
The Magellan probe was launched from the Space Shuttle
Atlantis in May 1989 and began orbiting Venus Aug. 10, 1990. The craft
uses radar beams to penetrate the planet's thick clocks and create
photograph-like images of the surface, showing features as small as
the size of a football field and yielding pictures 10 times better
than any previous results.
``The mapping of Venus is unique in the history of
cartography,'' said Joel Russell of the USGS in Flagstaff, Ariz.
``Never has so much territory been discovered and mapped in so short
a period of time.''
Despite problems with the craft that periodically interrupt
the work, the craft is expected to photograph 82 percent of the
surface by May 15.
Venus is Earth's twin in the solar system in many ways. Both
planets are about the same size and mass, are relatively close to the
Sun and were probably nearly identical early in the solar system's
history.
But the environments of the planets diverged at some point,
leaving Venus the victim of a runaway greenhouse effect that produced
surface temperatures hot enough to melt lead and pressures comparable
to 3,300 feet under Earth's oceans.
|
| 456.288 | MAGELLAN Update - March 11 | ADVAX::KLAES | All the Universe, or nothing! | Tue Mar 12 1991 12:42 | 35 |
| From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 03/11/91
Date: 12 Mar 91 00:47:11 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
March 11, 1991
The Magellan spacecraft is performing nominally. All but one of
the STARCALS (star calibrations) during the weekend were successful.
The DESATS (desaturations of the reactions wheels) were successful.
The spacecraft temperatures continue to be in the acceptable
range. Bay 10 of the spacecraft bus has gone up slightly and is
currently at 68 degrees C, with an alarm limit of 75 degrees C.
The Spacecraft Team is performing a sequence load of AACS
(Attitude and Articulation Control Subsystem) Memory B, which had been
disabled since soon after the second spacecraft anomaly last August.
A memory readout test is scheduled for tomorrow. When the testing is
complete later this week, the new sequence load will make Memory B
fully functional and restore the memory redundancy.
The weekly command upload M1072 with its associated parameter
files is scheduled for tomorrow evening.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@mars.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |___ M/S 301-355 | Change is constant.
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 |
|_____|/ |_|/ |_____|/ |
|
| 456.289 | | 7875::NOONAN | FRIVOL ATTACK!!!! wheeeeeeeeeee | Tue Mar 12 1991 14:59 | 8 |
| RE: .287
Does anyone know what the six main religions are? I have some women in
mind, and I want to be sure they are not ineligible.
Thanks,
E Grace
|
| 456.290 | My guess on 5 of them | 19576::FISHER | Pursuing an untamed ornothoid | Tue Mar 12 1991 16:02 | 10 |
| Christianity
Judaism
Islam
Budism
Hinduism
???
(Or maybe Christianity is broken into Protestant and Catholic? I doubt it.)
Burns
|
| 456.291 | | PRAGMA::GRIFFIN | Dave Griffin | Tue Mar 12 1991 16:13 | 13 |
| My guess would be:
Buddhism
Confucianism
Christianity (Orthodox Eastern, Protestantism, Roman Catholicism)
Hinduism
Islam
Judaism
Confucianism comes close to both Baha'i and Shinto as far as membership
goes. Taoism is another candidate. I'm pretty sure about the other five.
- dave
|
| 456.292 | MAGELLAN Update - March 12 | ADVAX::KLAES | All the Universe, or nothing! | Tue Mar 12 1991 18:53 | 46 |
| From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 03/12/91
Date: 12 Mar 91 19:08:50 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
March 12, 1991
The Magellan spacecraft is performing nominally. All but one of
the STARCALS (star calibrations) yesterday were successful. The STARCAL
on orbit #1680 failed due to a foreground rejection of one star.
The Project has been experiencing some difficulty with X-band
downlink communications. The signal level has been suppressed about 4
db below the predicted levels by a spur which has appeared, possibly
due to increasing temperatures. This has resulted in some noisy radar
mapping data, especially near the southern end of the mapping swaths,
and the loss of some engineering data.
Analysis of telecommunications performance, including a "no
uplink" test, has verified that the X-band communications problem is
on-board the spacecraft rather than at the DSN (Deep Space Network)
stations. Several options for isolating and correcting the condition
are being reviewed, including on-board component switching and
possibly shifting the uplink frequency.
The Spacecraft Team successfully completed the load of the AACS
(Attitude and Articulation Control Subsystem) Memory B yesterday, and
is presently performing memory readout test. When the testing is
completed, the new sequence load will make Memory-B fully functional
and restore the memory redundancy. This new memory load also included
a fault detection scheme which would take the memory off-line if it
experienced another stuck bit.
The upload of command sequence M1072, with its associated radar control
parameter and mapping quaternion files is scheduled for this evening.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@mars.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |___ M/S 301-355 | Change is constant.
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 |
|_____|/ |_|/ |_____|/ |
|
| 456.293 | | DECWIN::FISHER | Pursuing an untamed ornothoid | Wed Mar 13 1991 15:38 | 5 |
| If it is performing nominally, how come it is having a problem with downlink?
;-)
Burns
|
| 456.294 | MAGELLAN Update - March 13; "nominal" status | ADVAX::KLAES | All the Universe, or nothing! | Thu Mar 14 1991 13:19 | 86 |
| From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 03/13/91
Date: 13 Mar 91 21:45:10 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
March 13, 1991
The Magellan spacecraft is performing nominally. Again, all but
one of the STARCALS (star calibrations) yesterday were successful.
The Project continues to experience difficulty with X-band
downlink communications. The communications problems were compounded
by DSN (Deep Space Network) hardware problems at the 34 meter tracking
station in Madrid this morning. Fortunately the other 34 meter station
was able to provide coverage of the X and S-band downlink, so no data
was lost.
The AACS (Attitude and Articulation Control Subsystem) Memory B
readout tests were successfully completed yesterday and spacecraft
controllers are continuing the process of loading Memory B today. The
upload of command sequence M1072, with its associated radar control
parameter and mapping quaternion files was completed late yesterday
and is executing properly.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@mars.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |___ M/S 301-355 | Change is constant.
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 |
|_____|/ |_|/ |_____|/ |
From: john@newave.UUCP (John A. Weeks III)
Newsgroups: sci.space,sci.astro
Subject: Re: Magellan Update - 03/11/91
Date: 14 Mar 91 04:17:43 GMT
Organization: NeWave Communications Ltd, Eden Prairie, MN
In article <19890@paperboy.OSF.ORG> dbrooks@osf.org (David Brooks) writes:
>In many articles, baalke@mars.jpl.nasa.gov (Ron Baalke) writes:
>|> The Magellan spacecraft is performing nominally...
>|> The Galileo spacecraft health continues to be excellent....
> Is nominal != excellent, or are we simply seeing the different
> approaches to PR by different writers? (not a flame; just curious).
I think that they used "nominal" to imply that Magellan is doing
very well considering the situation. While Magellan has returned a
ton of great data and has shead a new light on our view of Venus, the
craft has experienced a few problems. The location of Venus, the Sun,
and Earth have contributed to an expected onboard temperature surge.
This has required some creative orbit work to try to balance the
temperature of the various spacecraft components. In the process, it
was discovered that some type of temperature shield has not been
working as well as planned, which has lead to an even higher
temperature. Then there are the sporadic computer glitches. And one
of the gyros failed just before Magellan entered orbit around Venus.
As always, the brilliant people at JPL and NASA have found ways to
keep Magellan running while maximizing the amount of data collected.
Keep in mind that just one or two strips of radar data from
Magellan would have been enough to make Magellan a major success
considering the amount of new information contained in those first
high resolution glimpses of Venus.
Galileo, on the other hand, has been using fuel at a lower than
projected rate. This leaves a large enough fuel margin to make a
second asteriod fly-by. Someone must have been paying attention to
the decimal places! And the pictures of Earth's Southern Pole and far
side of the Moon are a nice bonus. There is one nagging problem that
Galileo's keepers are watching--an AC/DC bus voltage inbalance. While
I am not an expert, it looks like there is small leakage path somewhere
between two wires. So far this has caused no operational problems,
and Galileo continues to perform as well as or better than expected.
-john-
--
===============================================================================
John A. Weeks III (612) 942-6969 john@newave.mn.org
NeWave Communications ...uunet!rosevax!tcnet!wd0gol!newave!john
===============================================================================
|
| 456.295 | MAGELLAN Update - March 14 | ADVAX::KLAES | All the Universe, or nothing! | Fri Mar 15 1991 14:53 | 39 |
| From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 03/14/91
Date: 15 Mar 91 03:14:55 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
March 14, 1991
The Magellan spacecraft is performing nominally. All of the
STARCALS (star calibrations) and DESATS (desaturations) yesterday were
successful.
Last night a command was sent to the spacecraft to switch from
Transmitter B to A. This appears to have cleared up the X-band
communications problem. This morning a good signal-to-noise ratio of
8.4 on the high rate data was observed.
During the reconfiguration of AACS (Attitude and Articulation
Control Subsystem) Memory B yesterday, some alarms were noted when
controllers reset the off-line power flag. Specifically, the
heartbeat loss counter was incremented and there was an indication of
an attempt by the AACS computer to access write-protected memory. So
the spacecraft controllers decided to put the off-line power flag to
its prior setting and delay the reactivation of AACS Memory B until
the reason for the alarms can be analyzed.
No spacecraft commanding is planned for today. Tomorrow, the
upload of tweak P1075, with the updates of the radar control parameter
and mapping quaternion files is planned.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@mars.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |___ M/S 301-355 | Change is constant.
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 |
|_____|/ |_|/ |_____|/ |
|
| 456.296 | MAGELLAN Update - March 15 | ADVAX::KLAES | All the Universe, or nothing! | Mon Mar 18 1991 18:46 | 60 |
| From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 03/15/91
Date: 16 Mar 91 01:09:51 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
March 15, 1991
The Magellan spacecraft is performing nominally. All of the
STARCALS (star calibrations) and DESATS (desaturations) yesterday were
successful. The downlink communications at both S and X-band are
significantly improved since the switch from Transmitter B to A.
Later today, the upload of tweak P1075, with the updates of the
radar control parameter and mapping quaternion files is planned.
CYCLE 2 ALTIMETRY
During the primary mission, most of the public's attention has
been focused on the radar imaging. But along with each radar image
swath, the Magellan spacecraft has collected an altimeter swath.
The altimeter antenna is mounted on the +X side of the High Gain
Antenna so that it essentially points straight down as Magellan swings
close to the surface. The altimeter "footprint" is about 10 km wide
at periapsis (lowest point of the orbit). Since the orbit-to-orbit
offset is about 20 km, to provide minimal overlap of the radar image
swaths, there is a gap between altimeter swaths of about 10 km at
periapsis.
During Cycle 2 the spacecraft will be turned around to perform
the radar mapping in a right-looking mode. The altimeter will still
be pointing straight down and the +Y side of the spacecraft will be
facing in the direction of travel.
While planning for Cycle 2, the mission planners discovered that
the altimeter tracks would fall exactly in line with the altimeter
track of Cycle 1. In order to improve the quality of altimeter data,
it was recommended that an Orbit Trim Maneuver (OTM) be performed to
place the Cycle 2 altimeter tracks between the previous ones. The
Project has approved performing the OTM.
The Orbit Trim Maneuver will not change the period of the orbit
nor the altitude or latitude of periapsis. By slightly rotating the
orbit around the node (an imaginary line drawn through the poles of
Venus), the necessary 10 km offset can be accomplished. The maneuver
will require a 30 minute "burn" of the small thrusters. It was
determined that this was a more reliable way to perform the OTM than
using the 445N rockets. The OTM will be performed in mid-May as the
mission moves into Cycle 2.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@mars.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |___ M/S 301-355 | Change is constant.
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 |
|_____|/ |_|/ |_____|/ |
|
| 456.297 | MAGELLAN Update - March 18 | ADVAX::KLAES | All the Universe, or nothing! | Tue Mar 19 1991 12:36 | 28 |
| From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 03/18/91
Date: 18 Mar 91 23:23:26 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
March 18, 1991
The Magellan spacecraft and its radar system are performing
nominally. All of the STARCALS (star calibrations) and DESATS
(desaturations) during the weekend were successful, with only two
star rejects.
The downlink communications at both S and X-band continue to be
excellent with signal to noise ratios very close to predicts. No
commanding is planned for today. Late tomorrow, the weekly mapping
command sequence, M1079, with its radar control parameter and mapping
quaternion files will be sent to the spacecraft.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@mars.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |___ M/S 301-355 | Change is constant.
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 |
|_____|/ |_|/ |_____|/ |
|
| 456.298 | MAGELLAN Updates - March 19-22 | ADVAX::KLAES | All the Universe, or nothing! | Tue Mar 26 1991 13:58 | 216 |
| From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 03/19/91
Date: 20 Mar 91 01:09:57 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
March 19, 1991
The Magellan spacecraft and its radar system are performing
nominally. All of the STARCALS (star calibrations) and DESATS
(desaturations) yesterday were successful.
Later today the weekly mapping command sequence, M1079, with its
radar control parameter and mapping quaternion files will be sent to
the spacecraft. Also being sent to the spacecraft today will be a
command sequence to perform Test #2 on the Flight Tape Recorder "A".
If approved later today, the final files to reload AACS (Attitude
and Articulation Control Subsystem) Memory "B" will be sent tomorrow.
Spacecraft engineers have determined the cause of the heartbeat loss
counts and the protected memory warnings observed last week while
trying to reactivate Memory B, so the process of restoring the full
redundancy of the AACS memories can now be completed. The new
on-board sequence includes fault detection which will quickly isolate
the memory in the event of a chip failure.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@mars.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |___ M/S 301-355 | Change is constant.
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 |
|_____|/ |_|/ |_____|/ |
From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 03/20/91
Date: 20 Mar 91 21:38:49 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
March 20, 1991
The Magellan spacecraft and its radar system are performing
nominally. All of the STARCALS (star calibrations) and DESATS
(desaturations) yesterday were successful. Only one star reject
was noted.
Magellan is now in its 1260th mapping orbit. The capture rate of
data on Earth is still about 94%, which is the equivalent of 1182
orbits on the ground. This covers almost 65% of the total Venus
surface area.
The weekly mapping command sequence, M1079, was be sent to the
spacecraft and is now executing. This upload contained a command
sequence to perform Test #2 on the Flight Tape Recorder "A."
Mission controllers are now uploading the final files to reload
the AACS (Attitude and Articulation Control Subsystem) Memory "B".
Two of the seven uplinks have been accomplished this morning. This
process will restore full redundancy to the AACS memories, and
includes fault detection which will quickly isolate the memory in the
event of a chip failure.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@mars.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |___ M/S 301-355 | Change is constant.
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 |
|_____|/ |_|/ |_____|/ |
From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update #2 - 03/20/91
Date: 20 Mar 91 21:40:48 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
DMS-A Tape Recorder Review
March 20, 1991
JPL, Martin Marietta, and Odetics conducted a review of the
progress in analyzing the DMS-A (Data Management Subsystem-A) tape
recorder problem on Monday, March 11 at JPL. Assessment of the data
played back from Test #3 on the spacecraft DMS-A tape recorder has
shown a number of areas which are confusing. Test #3 involved
recording known test data patterns on each of the four tape recorder
tracks at both the high and low record rates in order to investigate
the "pattern sensitivity" of the problem.
The tape recorder motor current seen in the real-time spacecraft
telemetry appeared normal, rather than showing the noise spikes
associated with the DMS-A problem. This noise is caused by the motor
control circuitry trying to track a noisy clock signal recovered from
the data on tape. Despite the apparently "good" motor current, the
replayed data itself appeared to be seriously degraded. Most
strikingly, no data at all appeared to be recovered from track 2, the
first of the DMS-A tracks to begin to go bad. This calls into
question the earlier Test #1 result, which had used the failure to
find data on an "erased" area of Track 2 to confirm that the erase
mechanism is working satisfactorily.
A second replay of the same recorded test data (from only Track
1) was performed on Friday, March 8, to attempt to resolve this
confusion. Early assessments of the second playback show substantial
differences from the first playback. In fact, the data appeared to be
quite good at first glance.
Martin and JPL are in the process of re-examining both data
playbacks to resolve these assessments. The ground tests at Odetics
have shown that several of the candidate failure mechanisms did not
cause the same pattern of data replay problems which have been
characteristic of DMS-A. In fact, the ground tests have shown the
units tested to be highly robust against the faults induced, including
failure of the fine erase head winding, partial failure of the coarse
erase head winding, and partial magnetization of the record head.
The most promising candidate failure mechanism to emerge from the
ground tests is a possible "stuttering" of the clock provided to the
tape recorder from the Command Data Subsystem (CDS) computer. By
inserting "extra" clock pulses, such a clock problem could cause the
data encoding/decoding mechanism to fail in a pattern similar to many
of the observed data errors. Such a clock problem could be caused by
ringing or noise affecting the clock transfer over a short length of
cable from the CDS to DMS-A. The transfer cable lengths to DMS-A and
DMS-B are equal, and no such problem has been seen on DMS-B.
The immediate actions after the review were to concentrate on
reaching a sound assessment of the real results from Test #3, so as to
separate true spacecraft problems from ground data handling anomalies.
In addition, the planning for the delayed Test #2 on the spacecraft,
using an area of tape which has not been used since cruise (well
before the DMS-A fault appeared) is continuing.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@mars.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |___ M/S 301-355 | Change is constant.
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 |
|_____|/ |_|/ |_____|/ |
From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 03/21/91
Date: 22 Mar 91 01:05:27 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
March 21, 1991
The Magellan spacecraft and its radar system are performing
nominally. All of the STARCALS (star calibrations) and DESATS
(desaturations of the reaction wheels) yesterday were successful, with
only one star reject. All of the communications margins, spacecraft
temperatures, and power levels are within the expected range. Magellan
is now in its 1268th mapping orbit. The capture rate of data on Earth
is still about 94%, so we have the equivalent of 1190 orbits on the ground.
Yesterday, mission controllers completed the uploading of the
final files to reload AACS (Attitude and Articulation Control
Subsystem) Memory "B". Today, they are in the process of six uplinks,
four related to a gyroscope static detection test and two related to
configuration of DMS-A (Data Management Subsystem-A) in preparation
for the Tape Recorder Test #2, which is part of the current command
sequence.
Processing of the data into science data products has been
running at or ahead of schedule. However, since it takes as long as
two weeks to receive the Original Data Record tapes from the DSN (Deep
Space Network) stations in Spain and Australia, the production of full
resolution image strips is currently about 150 orbits less than the
count of orbits on the ground.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@mars.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |___ M/S 301-355 | Change is constant.
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 |
|_____|/ |_|/ |_____|/ |
From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 03/22/91
Date: 23 Mar 91 03:24:03 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
MAGELLAN STATUS REPORT
March 22, 1991
The Magellan spacecraft and its radar systems are performing
nominally. All of the STARCALS (star calibrations) and DESATS
(desaturations) yesterday were successful, but three star scans were
only partially successful due to star rejects. The average attitude
update was 0.02 degrees.
All of the communications margins, spacecraft temperatures and
power levels are within expected ranges. Yesterday, mission
controllers successfully completed the four uplinks related to a
gyroscope static detection test, and two uplinks to prepare for the
DMS-A (Data Management Subsystem-A) Test #2 which being performed today.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@mars.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |___ M/S 301-355 | Change is constant.
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 |
|_____|/ |_|/ |_____|/ |
|
| 456.299 | Two more images | PRAGMA::GRIFFIN | Dave Griffin | Tue Mar 26 1991 21:00 | 17 |
| My phone bill is going to be a bit high this month, but you folks are the
benefactors!
Two new magellan images are available at pragma::public:[nasa]
MGN_Lavinia_1.GIF - Lavinia region
MGN_Perspect_1.GIF - "Synthesized" 3-d perspective view (if you've seen
the Magellan movie clip, then this is akin to a frame from that movie --
really spectacular.)
Technical information available in the .INFO files. There are several
more images in the queue. The folks at JPL are being quite kind in making
this stuff available so quickly and in public-usable forms.
- dave
|
| 456.300 | Venus may be venting its internal heat | ADVAX::KLAES | All the Universe, or nothing! | Wed Apr 03 1991 18:30 | 87 |
| From: yee@trident.arc.nasa.gov (Peter E. Yee)
Newsgroups: sci.space
Subject: Hot spot, volcanic-like features identified on Venus (Forwarded)
Date: 3 Apr 91 17:33:47 GMT
Sender: usenet@news.arc.nasa.gov (USENET Administration)
Organization: NASA Ames Research Center, Moffett Field, CA
[Ron seems to off-line due to a system change, so I'm taking the liberty of
posting this for him. We will be making the Magellan CD-ROM available for
anonymous ftp from the SPACE archives on ames.arc.nasa.gov (just as soon as
we get it!) -PEY]
Paula Cleggett-Haleim
Headquarters, Washington, D.C. March 29, 1991
(Phone: 202/453-1547)
Jim Doyle
Jet Propulsion Laboratory, Pasadena, Calif.
(Phone: 818/354-5011)
RELEASE: 91-48
HOT SPOT, VOLCANIC-LIKE FEATURES IDENTIFIED ON VENUS
The planet Venus may be venting interior heat through giant
hot spots called coronae, a form of volcanism, a Magellan scientist
said at NASA's Jet Propulsion Laboratory, Pasadena, Calif..
"Coronae may be hot spots, the surface expression of hot
material rising from the interior of the planet," said Dr. Ellen
Stofan, a geologist on the Magellan project.
She said coronae are among the several types of circular
features associated with volcanism that have been identified on Venus.
Others include large volcanoes and spider web-shaped features called
arachnoids.
Coronae are circular or oval features as much as a mile
or more high surrounded by a ring of ridges and troughs. They range in
size from about 100 miles to more than 600 miles in diameter and are
seen in many low-lying plains regions on Venus.
Arachnoids are circular volcanic structures surrounded by
complex fractures. They may form by volcanism in a region where the
surface is pulling apart or extending, Stofan said.
"Coronae, arachnoids and volcanoes are ways in which Venus
transfers heat from its interior out to the surface," she said. "On
Earth, this loss or transfer of heat is dominated by plate tectonics.
It is too early to determine if Venus also has plate tectonics, but hot
spots do seem to be important to Venus' heat loss."
"High-resolution Magellan data have revealed many exciting new
aspects of coronae," she said. The Magellan spacecraft has mapped with
imaging radar more than 67 percent of Venus since last Sept. 15. The
first 243-day mapping cycle ends May 15.
Project management also announced that the first CD-ROM, or
compact disc read- only-memory, containing Magellan mosaics of radar
images was released to the National Space Science Data Center (NSSDC)
for public distribution. One CD-ROM can hold about 600 megabytes of
information or about 270,000 pages of text. The information can be
easily accessed with a computer using a CD-ROM reader similar to audio
CD-players.
Magellan CD-ROMs containing 10 Magellan mosaics each, or
560 individual images, are produced by JPL and Dr. Raymond Arvidson of
Washington University, St. Louis.
"Distribution of data to the public by CD-ROM will revolutionize
the way science is done," said Project Scientist Dr. Steve Saunders.
"CD-ROM technology provides an excellent way to store, distribute and
access large volumes of data. "I can see a time in the near future
when students all over the country can be using this kind of data in
classwork and projects," he said.
The first Magellan CD-ROM may be obtained through the NSSDC,
Goddard Space Flight Center, Code 601.4, Greenbelt, Md. 20771. Several
more CD-ROMs will be delivered to the NSSDC in the coming months,
Saunders said. All Magellan mosaics will eventually be placed on
CD-ROMs and delivered to the NSSDC for distribution to the public.
Black and White photographs to illustrate this story are available
to media representatives by calling NASA Headquarters Audio/Visual
Branch at 202/453-8373. Photo numbers are 91-H-181 to -184.
|
| 456.301 | MAGELLAN ahead of schedule | ADVAX::KLAES | All the Universe, or nothing! | Fri Apr 05 1991 12:33 | 67 |
| From: clarinews@clarinet.com (ROB STEIN, UPI Science Editor)
Newsgroups: clari.tw.space,clari.tw.science
Subject: Venus mapping ahead of schedule
Date: 4 Apr 91 23:08:23 GMT
WASHINGTON (UPI) -- The Magellan space probe wrapped up the
primary phase of its job mapping the shrouded surface of Venus more
than a month early and NASA has approved a second mapping cycle,
officials announced Thursday.
Despite periodically losing contact with its handlers on
Earth, Magellan reached the goal of mapping 70 percent of the planet
Wednesday and by May 15 will have mapped 84 percent of the planet's
surface, said Tony Spear, project manager at the Jet Propulsion
Laboratory in Pasadena, Calif.
Because of the quality of the images produced by the craft and
the excitement they have generated among scientists, NASA approved the
second 243-day mapping cycle to begin May 16, the agency said.
The first objective of the extended mission is to collect the
remaining 16 percent of the map of the planet's surface, including the
south pole, which has never been imaged, NASA said.
Other surface features will be imaged from a different angle
to provide new perspectives and images from the two cycles will be
compared to detect any activity on the surface, Spear said.
Beginning in the middle of November, every fourth orbit will
be dedicated to gathering data about the planet's gravity, NASA said.
Instead of mapping the surface of the planet on those orbits,
the craft's high-power antenna will point toward Earth and slight
changes in the radio signal resulting from variations in Venus's
gravitational tug on the craft will help scientists determine local
gravity changes. That information will provide insight into the
interior processes of the planet.
In addition, NASA is considering a number of experiments that
would use the craft's radar to acquire more detailed topography of the
planet, NASA said.
Near the end of the mission, the craft may be dipped into the
upper atmosphere of Venus to drag it into a circular orbit, a
previously untried process called ``aerobraking,'' NASA said.
In addition to providing valuable engineering demonstration,
the new orbit ``would greatly enhance science returns by permitting
global, high-resolution gravity imaging data acquisition,'' Spear said.
Magellan was launched from the space shuttle Atlantis on May
4, 1989 and began orbiting Venus on Aug. 19, 1990. The 2 1/2-ton
solar-powered spacecraft uses radar beams to pierce the thick layer of
clouds that covers Venus and produce the most detailed images ever of
the planet's tortured surface.
The $551 million craft has had problems with a data recorder
and a computer unit that occasionally knocks the craft out of contact
with Earth. But technicians have been able to reestablish contact and
compensate for the problem.
Scientists hope to learn more about Earth by studying Venus
because the two planets are similar in many ways. Venus, however, was
the victim of a runaway greenhouse effect, creating surface temperatures
hot enough to melt lead and pressures comparable to those found 3,300
feet under the ocean.
|
| 456.302 | MAGELLAN Update - April 4 | ADVAX::KLAES | All the Universe, or nothing! | Fri Apr 05 1991 18:33 | 101 |
| From: yee@trident.arc.nasa.gov (Peter E. Yee)
Newsgroups: sci.space
Subject: Magellan Status for 04/04/91 (Forwarded)
Date: 5 Apr 91 18:55:15 GMT
Sender: usenet@news.arc.nasa.gov (USENET Administration)
Organization: NASA Ames Research Center, Moffett Field, CA
[Posting this until Ron gets back on the net. -PEY]
MAGELLAN STATUS REPORT
April 4, 1991
The Magellan spacecraft and its radar system are performing well.
Six of seven star calibrations were successful Wednesday with nominal
attitude updates.
The Goldstone Deep Space Network station experienced some
equipment problems during Wednesday's track and low rate telemetry was
lost for a short period. The problems were quickly corrected.
The project announced it had achieved more than 70 percent
mapping coverage of Venus. That was the first of the prime mission
objectives. By the time the first cycle ends on May 15, project
officials said they expect to have acquired 84 percent of the planet's
surface in captured data.
From: yee@trident.arc.nasa.gov (Peter E. Yee)
Newsgroups: sci.space
Subject: Magellan achieves primary mission objective early (Forwarded)
Date: 5 Apr 91 18:55:57 GMT
Sender: usenet@news.arc.nasa.gov (USENET Administration)
Organization: NASA Ames Research Center, Moffett Field, CA
Paula Cleggett-Haleim
Headquarters, Washington, D.C. April 4, 1991
(Phone: 202/453-1547)
Robert MacMillin
Jet Propulsion Laboratory, Pasadena, Calif.
(Phone: 818/354-5011)
RELEASE: 91-49
MAGELLAN ACHIEVES PRIMARY MISSION OBJECTIVE EARLY
The Magellan Project at NASA's Jet Propulsion Laboratory,
Pasadena, Calif., claimed an early victory today and announced that
the spacecraft had achieved its objective for the primary phase of the
Venus mission more than a month before the end of the first 243-day
mapping cycle. That is one Venus rotation beneath the orbiting
spacecraft.
Project Manager Tony Spear said because of the quality of the
radar images and the excitement they have generated in the scientific
community, an extended mission for a second 243-day mapping cycle has
been approved by NASA and will begin May 16.
Magellan reached its goal of mapping 70 percent of the planet
on Wednesday, said Spear, adding that by the end of the first mapping
cycle May 15, the spacecraft will have acquired 84 percent of the
planet's surface.
The radar imager used to penetrate the thick clouds of Venus
and map the surface has worked flawlessly, Spear said. He added that
the spacecraft is sufficiently healthy to continue mapping Venus well
into this decade, "providing a windfall of additional, exciting
science return."
The first objective of the extended mission is to collect the
remaining 16 percent of the map, including the south pole, which has
never been imaged. Other surface features will be imaged from a
different view angle to yield a new perspective, and image comparisons
from one mapping cycle to the next will be made to look for surface
activity, Spear said.
Beginning in mid-November, every fourth orbit will be
dedicated to acquiring gravity data. Instead of mapping the surface
on those orbits, Magellan's high-gain antenna will point to Earth and
slight changes in the radio signal, resulting from variations in
Venus' tug on the spacecraft, will help scientists determine local
gravity changes. That information will provide insight into the
interior processes of the planet. Additionally, a number of
experiments are under study which would use the radar in different
modes to acquire higher resolution topography.
Finally, near the end of the Magellan mission, the spacecraft
may be dipped into the upper atmosphere of Venus to drag it into a
circular orbit, a previously untried process called aerobraking. The
maneuver would be a valuable engineering demonstration for future
missions, Spear said.
"More importantly," he said, "a circular orbit would greatly
enhance science returns by permitting global, high-resolution gravity
and imaging data acquisition."
Magellan is managed by JPL for NASA's Office of Space Science
and Applications, NASA Headquarters, Washington, D.C. The Hughes
Aircraft Co. developed and operates the radar instrument, and the
Martin Marietta Corp. built and operates the spacecraft.
|
| 456.303 | MAGELLAN Update - April 10 | ADVAX::KLAES | All the Universe, or nothing! | Thu Apr 11 1991 12:33 | 28 |
| From: yee@trident.arc.nasa.gov (Peter E. Yee)
Newsgroups: sci.space
Subject: Magellan Status for 04/10/91 (Forwarded)
Date: 10 Apr 91 23:15:44 GMT
Sender: usenet@news.arc.nasa.gov (USENET Administration)
Organization: NASA Ames Research Center, Moffett Field, CA
MAGELLAN STATUS REPORT
April 10, 1991
The Magellan spacecraft and its radar system are performing
normally.
The star calibrations continue to produce occasional filter
rejections of the reference stars, but the attitude updates
remain in the acceptable range and the pointing accuracy is very
precise.
The weekly command sequence was successfully sent to
Magellan along with the radar control files and that sequence is
now being executed.
Today marks the 243rd day since Magellan went into orbit
around Venus on August 10, 1990. That means that Venus has turned
once on its axis since Magellan arrived and the spacecraft is
now back to the point of the first orbit. Mapping started 36
days later, so the first mapping cycle will be complete on May 15.
|
| 456.304 | 38 new magellan images available | PRAGMA::GRIFFIN | Dave Griffin | Fri Apr 12 1991 19:27 | 14 |
| Nine megabytes worth of new images are available at:
pragma::public:[nasa]mgn*.gif (not all of these are new).
Many have technical information accompanying them. All files are
in GIF format. I will not be converting them to DDIF anymore (or at
least for quite some time).
I'm trying to develop a better indexing system, and I have not reviewed
all of the images to sort out possible duplicates. Since most people
just like to browse, I thought that promptness was better than
thoroughness.
- dave
|
| 456.305 | Venus is geologically active | ADVAX::KLAES | All the Universe, or nothing! | Tue Apr 16 1991 15:33 | 66 |
| From: yee@trident.arc.nasa.gov (Peter E. Yee)
Newsgroups: sci.space
Subject: Venus described as volcanic and geologically active (Forwarded)
Date: 13 Apr 91 01:14:00 GMT
Sender: usenet@news.arc.nasa.gov (USENET Administration)
Organization: NASA Ames Research Center, Moffett Field, CA
Paula Cleggett-Haleim
Headquarters, Washington, D.C. April 12, 1991
(Phone: 202/453-1549)
Jim Doyle
Jet Propulsion Laboratory, Pasadina, Calif.
(Phone: 818/354-5011)
RELEASE: 91-53
VENUS DESCRIBED AS VOLCANIC AND GEOLOGICALLY ACTIVE
Widespread volcanism and a geologically active surface were
descriptions of the planet Venus presented today in the first
published papers by members of the Magellan Project science team at
NASA's Jet Propulsion Laboratory, Pasadena, Calif.
In the papers published in Science magazine, Magellan
scientists described geologic features of Earth's sister planet as
they begin the unprecedented task of mapping an Earth-size planet.
The reports describe extensive and explosive volcanism, tectonic
deformations, mountain belts and a number of impact craters that
indicate a relatively young surface age of a few hundred million
years.
Science team members described several types of lava flows,
evidence of lava rivers hundreds of miles long and craters created
by meteorite impacts that caused surface material to be ejected as
far as 600 miles.
The Magellan spacecraft is producing comprehensive image and
altimetry data for the planet Venus," said Project Scientist Stephen
Saunders and his co-authors in one of the papers.
The Magellan spacecraft was launched May 4, 1989, and began
mapping Venus on Sept. 15, 1990. Its primary mission goal of
mapping 70 percent of the planet was accomplished April 3. Project
officials said that when the first mapping cycle of 243-days -- one
Venus rotation beneath the orbiter -- ends on May 15, a total of 84
percent of the planet's surface will have been acquired.
NASA officials announced last week that because of the
excellence of the radar images produced by the spacecraft and the
excitement they have generated in the science community, a second
mapping cycle has been approved.
The first priority of the second cycle, beginning May 16, will
be to acquire the remaining 16 percent of the planet's surface in
radar imagery, including the south pole which has not been imaged by
spacecraft before.
The papers, written by science team members from JPL and other
American and foreign institutions, covered the first 21 days of
Magellan radar image data.
The Magellan Project is managed by the Jet Propulsion
Laboratory for NASA's Office of Space Science and Applications, NASA
Headquarters, Washington, D.C.
|
| 456.306 | MAGELLAN in April 12 SCIENCE magazine | ADVAX::KLAES | All the Universe, or nothing! | Wed Apr 17 1991 18:00 | 12 |
| From: heskett@titan.tsd.arlut.utexas.edu (Donald Heskett)
Newsgroups: sci.astro
Subject: Magellan
Date: 17 Apr 91 17:23:13 GMT
Sender: news@titan.tsd.arlut.utexas.edu
Organization: Applied Research Laboratories, University of Texas at Austin.
Those of you awaiting hard results from Magellan can rejoice,
because much of the 12-April-1991 issue of SCIENCE is devoted to
Magellan. There are roughly 100 pictures. Also, there is an entire
paper about the Magellan radar system.
|
| 456.307 | MAGELLAN Update - April 25; Venus winds | ADVAX::KLAES | All the Universe, or nothing! | Fri Apr 26 1991 13:27 | 100 |
| Article 29863
From: yee@trident.arc.nasa.gov (Peter E. Yee)
Newsgroups: sci.space
Subject: Magellan Status for 04/25/91 (Forwarded)
Date: 26 Apr 91 09:08:48 GMT
Sender: usenet@news.arc.nasa.gov (USENET Administration)
Organization: NASA Ames Research Center, Moffett Field, CA
MAGELLAN STATUS REPORT
April 25, 1991
The Magellan spacecraft and its radar system are performing very
well. All star calibrations and momentum wheel desaturations Wednesday
were fully successful.
After a day of 12-minute "hide" periods in which the spacecraft
is turned to put it in the shade of its high-gain antenna for thermal
control, the project reports a definite cooling trend. Most parts of
the spacecraft and radar sensor are down an additional two degrees.
Today, controllers sent up a non-standard command to reset the
solar array drive mechanism. In addition to shading the spacecraft
instrument bays, the solar arrays are turned to prevent too much
reflected sunlight on the spacecraft.
Magellan passed its 1,525th mapping orbit today and is
approaching the 80 percent mark in its coverage of Venus' surface,
which will be passed by this weekend. The primary mission cycle
requirement was 70 percent.
Article 29865
From: yee@trident.arc.nasa.gov (Peter E. Yee)
Newsgroups: sci.space
Subject: Magellan scientists study surface of Venus (Forwarded)
Date: 26 Apr 91 09:06:57 GMT
Sender: usenet@news.arc.nasa.gov (USENET Administration)
Organization: NASA Ames Research Center, Moffett Field, CA
Paula Cleggett-Haleim
Headquarters, Washington, D.C. April 26, 1991
(Phone: 202/453-1547)
Jim Doyle
Jet Propulstion Laboratory, Pasadena, Calif.
(Phone: 818/354-5011)
RELEASE: 91-63
MAGELLAN SCIENTISTS STUDY SURFACE OF VENUS
Magellan scientists at NASA's Jet Propulsion Laboratory (JPL),
Pasadena, Calif., are studying the surface features on Venus caused by
wind in the planet's dense atmosphere, Project Scientist Steve
Saunders said today.
The movement of dust and sand is an important geological
process on planets with atmospheres, he said. The surface pressure of
Venus' atmosphere is 90 times that of Earth's.
Soviet landers and the U.S. Pioneer probes measured wind
speeds near the surface of Venus at 2 to 4 miles per hour (1 to 2
meters per second). Based on theory and laboratory experiments, that
wind speed is very close to the speed required to move sand grains on
Venus, Saunders said. Accumulations of blown sand and dust can
blanket large regions and produce visible patterns in the Magellan
radar images, he stated.
"The most prominent wind features in the Magellan images of
Venus are wind streaks," Saunders said. "Streaks form in the lee of
topographic obstacles by the deposition or removal of sand and dust
and can be used as indicators of the direction of the most intense
winds," he stated.
Many large impact craters on Venus have nearby wind streaks
that may have been caused by the violent winds generated during the
impact event or that may be the result of a slower process of
subsequent wind movement of the fine impact debris.
Magellan has mapped more than 78 percent of the planet and by
the time the primary mission cycle ends May 15, will have mapped about
84 percent, project officials said.
Project Manager Tony Spear said a newly adopted strategy to
protect the spacecraft from the heat of direct sunlight has been
successful in cooling the spacecraft. Magellan has been growing
warmer as a result of changes in the geometry of Venus, Earth and the
sun and the time the spacecraft spends broadside to the sun. A
strategy, called "two-hide" which results in slightly shorter imaging
swaths, protects the spacecraft by hiding it behind the large antenna
and by turning the solar panels away for periods of time to reduce
reflection. The Magellan project is managed by JPL for the Office of
Space Science and Applications.
- end -
Two photographs, one showing wind streaks near the crater Mead
and the other depicting an area of lava flow on Venus, are available
from NASA's Audio Visual Branch at 202/453-8373.
|
| 456.308 | MAGELLAN Update - May 8 | 25626::KLAES | All the Universe, or nothing! | Thu May 09 1991 11:54 | 24 |
| Article 30398
From: yee@trident.arc.nasa.gov (Peter E. Yee)
Newsgroups: sci.space
Subject: Magellan Status for 05/08/91 (Forwarded)
Date: 8 May 91 22:23:51 GMT
Sender: usenet@news.arc.nasa.gov (USENET Administration)
Organization: NASA Ames Research Center, Moffett Field, CA
MAGELLAN STATUS REPORT
May 8, 1991
The Magellan spacecraft, now just seven days from completing its
first cycle of Venus mapping, is continuing its successful performance.
All of the communications margins, spacecraft temperatures and power
levels continue to be within the expected range.
The present thermal environment requires Magellan to shade the
equipment bus with the high-gain antenna for two 36-minute periods in
each orbit. It also requires the solar panels to be pointed 45 degrees
away from the normal attitude to reduce excess electrical power.
The strategy cuts about 15 minutes from each mapping pass, ending
each image swath at 7 degrees north latitude.
|
| 456.309 | Magellan Status Reports - May 9th - May 15th | PRAGMA::GRIFFIN | Dave Griffin | Thu May 16 1991 18:48 | 187 |
| MGN REPORT 5/9
AJS
5-09-91
9:00 AM
MAGELLAN STATUS REPORT
1. The Magellan spacecraft and its radar system are
performing nominally.
2. Six of the seven STARCALS yesterday were fully successful,
with attitude updates averaging 0.022 degree.
3. Spacecraft equipment bays 7 and 10 are now peaking at
41.5xC and 46.5xC respectively. This is five degrees
lower than the temperature peaks seen before we started
the 36 minute hide periods yesterday.
3. Tomorrow spacecraft controllers are planning to send up a
non-standard command to reset the Heartbeat Loss Response
in preparation for the Orbit Trim Maneuver included in
next week's command sequence. They will also be sending
up the standard "Tweak" and update of the radar control
parameter file.
4. Magellan is now in its 1628th mapping orbit and just
passed the 83% mark in its coverage of the Venus surface.
--------------------------------------------------------------------------
MGN REPORT 5/10
AJS
5-10-91
9:00 AM
MAGELLAN STATUS REPORT
1. At 1:22 AM PDT this morning the Magellan spacecraft
experienced a "stroll-about" anomaly when it failed
to re-establish communications with Earth after the
scheduled star calibration maneuver.
2. At 7:26 AM PDT S-band communications were reacquired
at DSS-65 in Madrid.
3. Engineering telemetry indicates that the spacecraft
is continuing its normal sequence of commands, but is
offpointed by about 4 degrees.
4. Commands are being sent to reconfigure the gyros and to
update the attitude reference parameters. Normal mapping
operations are expected to resumed after a successful star
calibration.
5. The next STARCAL will occur about 11 AM PDT. Spacecraft
controllers are working quickly to prepare the attitude
correction and to change the innovation bound, but the
spacecraft will be behind Venus (as viewed from Earth)
from 9:24 to 9:50 AM, so there is the possibility that the
correction may not be completed until the STARCAL at 2:20
PM PDT.
-------------------------------------------------------------------------------
MGN REPORT 5/14
AJS
5-14-91
9:00 AM
MAGELLAN STATUS REPORT
1. The Magellan spacecraft and its radar system are
performing nominally.
2. All STARCALS and DESATS yesterday were successful, with
attitude updates averaging 0.017 degree.
3. Late today, the weekly command sequence M1135 will be sent
to Magellan along with the radar control parameter and
mapping quaternion files. The new mapping sequence will
continue the two 36-minute "hide" periods in each orbit,
which result in mapping swaths which end just after
periapsis at 7 degrees north latitude.
4. This new mapping sequence also includes an Orbit Trim
Maneuver, to be executed on Friday, which will move the
orbit track about 10 km to one side so that the altimeter
swaths during Cycle 2 will interleave those from Cycle 1.
-------------------------------------------------------------------------------
MGN REPORT 5/15
AJS
5-14-91
9:00 AM
MAGELLAN SPECIAL REPORT
ORBIT TRIM MANEUVER
While planning for Cycle 2, the mission planners discovered
that the altimeter tracks would fall exactly in line with the
altimeter track of Cycle 1. In order to improve the quality
of altimeter data, it was recommended that an Orbit Trim
Maneuver (OTM) be performed to interleave the Cycle 2
altimeter tracks between the previous ones. In March, the
Project approved performing the OTM, and planning was started
on the exact maneuver sequence.
The OTM has been included in the M1135 command sequence and
will be performed on Friday morning, May 17, 1991 during Orbit
#2173. Radar mapping will be suspended at the start of Orbit
#2172 and the spacecraft will be configured for the OTM. This
includes resetting attitude control parameters and switching
to the Medium Gain Antenna (MGA). The maneuver will require a
33.4 minute "burn" of the small thrusters. These are the same
thrusters that are used every other orbit to maintain the
spacecraft position during the reaction wheel desaturation.
The burn will start at 11:13:33 AM PDT, and will last for
2005.27 secs. The one-way light time is approximately 8
minutes, so the start and end of the OTM would be observed on
Earth at 11:21 and 11:55 AM PDT respectively (although the
Earth will be outside the MGA cone angle). The spacecraft
switches back to the High Gain Antenna at about 7:00 PM PDT.
The Orbit Trim Maneuver will not change the period of the
orbit nor the altitude or latitude of periapsis. By slightly
rotating the orbit around the node (an imaginary line drawn
through the poles of Venus), the necessary 11 km shift at the
equator can be accomplished. See Figure 2. The shift is
counter-clockwise, as viewed from the North Pole of Venus, so
the offset is positive in longitude.
Normal, left-looking, radar mapping will resume with Orbit
#2176 at 7:46 PM and continue until the start of the M1142
mapping sequence, when we shift to right-looking radar
mapping.
-------------------------------------------------------------------------------
AJS
5-15-91
9:00 AM
MAGELLAN STATUS REPORT
1. The Magellan spacecraft and its radar system are
performing nominally.
2. All STARCALS and DESATS yesterday were successful, with
attitude updates averaging less than 0.02 degree.
3. The weekly command sequence M1135 was sent to Magellan and
will begin execution later today. The new mapping
sequence will continue the two 36-minute "hide" periods in
each orbit.
4. This new mapping sequence also includes an Orbit Trim
Maneuver, to be executed on Friday, which will move the
orbit track about 10 km to one side so that the altimeter
swaths during Cycle 2 will interleave those from Cycle 1.
5. Magellan is now approaching "closure," when we return to
the strip of Venus which was covered when we began radar
mapping operations on September 15, 1990. This will occur
when we complete orbit #2165 tomorrow morning at 11:10 AM
PDT.
|
| 456.310 | Magellan Status Report - May 17th | PRAGMA::GRIFFIN | Dave Griffin | Sun May 19 1991 13:35 | 57 |
| MGN REPORT 5/17
AJS
5-17-91
9:00 AM
MAGELLAN STATUS REPORT
1. The Magellan spacecraft and radar system are performing
nominally as we begin the second cycle around Venus.
2. Six of the seven STARCALS yesterday were fully successful,
with attitude updates averaging 0.022 degree.
3. Mapping was suspended at 6:43 AM PDT this morning in pre-
paration for the Orbit Trim Maneuver, which will occur at
11:13 AM. The OTM burn, using the small thrusters, will
last 33.4 minutes.
4. The spacecraft has been switched from the High Gain
Antenna to the Medium Gain Antenna. The OTM enable command
has been sent and successfully received by the spacecraft.
5. The OTM will shift the orbit about 11 km, so that the
altimeter tracks of Cycle 2 will interleave those
collected during Cycle 1.
6. Magellan is scheduled to resume normal mapping with orbit
#2176 at 7:46 PM PDT this evening.
MAGELLAN STATUS REPORT
May 17, 1991
The Magellan spacecraft, now in its second mapping cycle, went
through an orbit trim maneuver today so it will not duplicate the
first cycle's altimeter data. The new altimeter track will
interleave with the first cycle's track.
In order to improve the quality of data, it was decided to
slightly rotate the spacecraft's orbit around the node -- an
imaginary line drawn through the poles of Venus.
Mapping was suspended at 6:43 a.m. PDT today in preparation
for the orbit trim maneuver which began at 11:33 a.m. The burn,
using the small thrusters, lasted for little more than 33 minutes.
The burn shifted the orbit about 11 kilometers (6.8 miles).
The spacecraft also was switched from the high-gain antenna to
the medium-gain antenna for the operation. Normal mapping is to
resume at 7:46 p.m.
The spacecraft and radar system are performing well. Six of
the seven star calibrations Thursday were fully successful.
|
| 456.311 | MAGELLAN's former troubles | 25626::KLAES | All the Universe, or nothing! | Tue May 28 1991 18:36 | 57 |
| Article 31379
From: pgf@delcano.mit.edu (Peter G. Ford)
Newsgroups: sci.space
Subject: Re: Magellan: heartbeat loss response
Date: 20 May 91 23:32:05 GMT
Sender: news@athena.mit.edu (News system)
Organization: MIT Center for Space Research
In article <77071@eerie.acsu.Buffalo.EDU>,
v096my2q@ubvmsc.cc.buffalo.edu (Mark A Wieczorek) writes:
> Has anyone been reading the magellan status reports? I keep coming
> across this term --- Heartbeat loss response --- and have no idea
> of what it is except that is has to be reset once in a while, especially
> during emergencies. Anyone have any ideas?
>
> Mark Wieczorek
Since nobody else has jumped in to answer this one, let me try. I was
analyzing Magellan data when some of those emergencies occurred, and
I came away from JPL with the following general explanation...
The Magellan commands and data system (CDS) contains 4 computers, two for
command control and two for attitude control (AACS). They communicate by
reading and writing into a pair of common RAM memories. Every few seconds,
I forget the exact time, an AACS will re-write a "heartbeat" word, which
is like a two-valued switch. It alternately sets this word on and off.
Each control computer monitors the heartbeat words and, if they don't see
them change periodically, they assume that either the RAM has failed or
the particular AACS is having trouble. This has now happened to Magellan
on several occasions.
Shortly after going into Venus orbit, two things happened at once--some
stray electrical noise caused an AACS to re-boot and a RAM went flakey.
The AACS heartbeat words weren't updated and the control computers noticed
this, but in the intervening time, the spacecraft had rotated away from
where the AACS thought it was pointing. In making automatic star sightings
to try to this figure out, the AACS apparently locked onto the wrong
star and pointed the high-gain antenna away from Earth. Hours later,
after another failure, perhaps caused by that bad RAM, the computers
"gave up" and called on low-level recovery software to relocate Earth.
A second failure, rather similar to the first, took place a few days
later, while Magellan was still in the low-level mode.
Since then, the CDS computers have been reprogrammed by their degsigners,
the engineers at the Martin Marietta Corp. in Denver, to anticipate the
heartbeat loss and react in a more "sensible" way. There have been a
couple of failures, and the AACS computers have re-booted, but Magellan
has never again completely lost touch with the JPL controllers. The AACS
computers have lost their pointing information, but quickly regained it
and only a few orbits of mapping data have been lost.
________________________
Peter Ford
MIT and Magellan Project
|
| 456.312 | Magellan Mapping of Venus Results Reported | PRAGMA::GRIFFIN | Dave Griffin | Wed May 29 1991 19:24 | 41 |
| RELEASE: 91-83
Magellan Project scientists today presented the results of
the first 243-day radar mapping cycle of Venus as the spacecraft
continued in a second cycle of exploring the cloud-shrouded
surface of Earth's nearest planetary neighbor.
Dr. Stephen Saunders, Project Scientist, gave a summary of
findings during the first cycle and compared radar images from the
first two orbits last August when the radar instrument was being
tested with new data covering the same surface area. Saunders
reviewed global features, emphasizing wind streaks, large features
called coronas and the continent-sized upland, Aphrodite Terra.
Dr. James Head, a Brown University member of the science
team, discussed volcanic features and global distribution of
volcanoes and described the search for surface changes during the
second mapping cycle.
Dr. Gordon Pettengill, Massachusetts Institute of
Technology Principal Investigator of the radar science group,
released new altimetry and radiometry results with emphasis on
western Aphrodite Terra and the peculiar characteristics of
festoon -- looped or curved -- lava flows.
New radar images were released, along with a new video
creating a simulated flight over a three-dimensional Venus
surface. The tape shows a large area of distinctive impact
craters and a closeup of strange volcanoes called "pancake domes."
The first mapping cycle, begun last Sept. 15, imaged 84
percent of the planet. The cycle ended May 15 and the second
cycle, to map the remainder of the surface, began immediately.
The spacecraft's orbit was trimmed on May 17 to enhance its
altimetry coverage of Venus. The altimetry instrument measures
the heights of features on the surface.
Saunders and the other Magellan scientists addressed a news
conference at NASA Headquarters, Washington, D.C.
|
| 456.313 | Magellan Status Reports 5/24, 5/28, 5/29 | PRAGMA::GRIFFIN | Dave Griffin | Thu May 30 1991 11:27 | 105 |
| MGN REPORT 5/24
AJS
5-24-91
9:00 AM
MAGELLAN STATUS REPORT
1. The Magellan spacecraft and radar system are performing
nominally. All STARCALS and DESATS yesterday were
successful.
2. The spacecraft started execution of the M1143 sequence at
4:54 PM PDT yesterday with Orbit #2219. Later today,
controllers will uplink an update to the Radar Control
Parameter File.
3. The current mapping sequence includes two 55-minute hide
periods in each orbit and offpointing of the solar panels
for thermal control. The adverse thermal environment will
continue until mid-July and we will not return to full
mapping swaths until July 24th.
4. It also switches to right hand, constant look angle radar
mapping in order to map the south pole. The first data
tape from this new sequence is being delivered from
Goldstone this morning and we are eagerly awaiting the
first images of the south polar region of Venus.
5. Magellan will continue to use the right hand, constant
look angle mapping strategy through most of Cycle 2, which
extends to mid-January 1992. It will return to left hand,
variable look angles for about 15 days in late June to
partially fill the Superior Conjunction gap.
MGN REPORT 5/28
AJS
5-28-91
9:00 AM
MAGELLAN STATUS REPORT
1. The Magellan spacecraft is continuing to perform nominally.
The star reject counter incremented by four over the three-
day weekend, but the attitude updates appear to be minimal.
2. There were also four miscompare counts between the Solar
Array Drive Mechanism commanded position and the sun sensor
indicated position, and this is being investigated.
3. Last Friday, the SAR Data Processing Team completed the first
test image swath of the right-looking, constant incidence
angle radar mapping. The results look very good and show an
area not previously imaged between 68 degrees south latitude
and the South Pole.
4. Tomorrow the M1150 command sequence will be sent to Magellan.
It will continue the right-look mapping of the area from
about 45 degrees south latitude to the South Pole and will
include two 55-minute hide periods in each orbit.
MGN REPORT 5/29
AJS
5-29-91
10:00 AM
MAGELLAN STATUS REPORT
1. The Magellan spacecraft and its radar system are performing
nominally. All STARCALS and DESATS yesterday were
successful.
2. Magellen is already in its 42nd orbit of right-hand mapping.
Due to thermal constraints which limit the mapping swaths to
about 9 minutes of each 3.25-hour orbit, the focus is on the
area between 45 degrees south latitude and the South Pole.
3. Later today the M1150 command sequence will be sent to
Magellan. It will continue the right-look mapping of the
extreme southern area and will include two 55-minute hide
periods in each orbit.
4. A press conference marking the end of Cycle 1 was held this
morning at NASA Headquarters. Participants included Dr. Wes
Huntress (NASA Solar System Exploration Division), Dr. Tommy
Thompson (MGN Science & Mission Planning Office), Dr. R.
Stephen Saunders (Project Scientist), Dr. Gordon Pettengill
(MIT, Principle Investigator) and Dr. James Head (Brown
Univ., Science Investigator). Preliminary global science
results were presented along with plans for the extended
mission.
|
| 456.314 | More new views of Venus from MAGELLAN | 25626::KLAES | All the Universe, or nothing! | Thu May 30 1991 12:29 | 100 |
| Article 1571
From: clarinews@clarinet.com (ROB STEIN, UPI Science Editor)
Newsgroups: clari.tw.space,clari.tw.science
Subject: Venus offers glimpse at Earth's past, future
Date: 29 May 91 19:25:50 GMT
WASHINGTON (UPI) -- The Magellan space probe's unprecedented
exploration of Venus has revealed a wracked and wretched planet that
may provide a glimpse into Earth's past and possible future, officials
said Wednesday.
NASA released six new images of Venus created by Magellan's
advanced radar mapping system and a dramatic, two-minute computer-
generated color video that takes viewers zooming over part of
the planet's previously shrouded surface at 200,000 mph.
The stunning images show a hellish, ruptured surface riddled
with craters, punctuated by towering volcanoes, scarred by massive
rifts and valleys, and dotted with strange lava formations resembling
giant pancakes and even a huge squashed insect.
``The results have been spectacular,'' said Wesley Huntress
Jr. at a news conference at NASA headquarters to formally announce the
completion of the first and primary phase of Magellan's mission.
``Magellan has removed the veil from planet Venus and now
we've been able to see entirely through Venus's perpetual cloud cover,
revealing a fascinating planet more different from her twin than any
of us would have imagined,'' he said.
By learning more about Venus, scientists hope to gain a better
understanding of Earth's past because the geological processes on both
planets should be similar.
``Venus may indeed be giving us a look into our past even
though what we're seeing on Venus is the present,'' said Steve
Saunders, project scientist from the Jet Propulsion Laboratory in
Pasadena, Calif. ``I think it's a very exciting kind of comparison.''
Venus could also offer a peek at Earth's future because while
the planets are similar in size and mass, Venus has surface
temperatures hot enough to melt lead and pressures comparable to those
found 3,000 feet under the ocean.
``What this mission is doing is giving us an understanding of
a planet that in respects...is very much like the Earth...but is
otherwise entirely different,'' Huntress said.
``What caused the difference in the evolution of the planet
Venus and the planet Earth to give us an environment which is
habitable to life and Venus one which is clearly not? It is important
to understand that,'' he said.
While scientists have found widespread evidence of volcanic
activity on Venus, including massive lava flows, they have yet to find
definitive proof of active volanoes. But they hope to find it
eventually, perhaps by viewing the same areas at different times to
detect change.
``It's highly probable that volcanism is going on on the
planet right now but it's sort of like the mystery novel,'' said James
Head, a geology professor at Brown University in Providence, R.I. ``We
need to find the smoking volcano.''
The $450 million craft, which costs about $43 million a year
to operate, has already begun the second phase of its mission, which
will include completing a full map of the planet and viewing previously
seen features in more detail and different angles, officials said.
Among the unique formations discovered by Magellan are large
circular features known as ``coronas,'' some of which are as large at
the continental United States, apparently formed by heat from inside
the planet.
``We see a variety of land forms, some of which are very very
bizarre,'' Head said.
Another feature was dubbed a ``tick'' because it is a large
round structure with fractures radiating out around it, resembling a
giant tick, he said. It may have been formed by molten lava, he said.
Scientists were surprised none of the formations found so far
appear to be more than 1 billion years old, indicating volcanic
activity may have changed most of the planet's surface relatively
recently, Saunders said.
Magellan was launched from the space shuttle on May 4, 1989,
and began orbiting Venus on Aug. 9, 1990. The 2 1/2-ton, solar-powered
craft began the mapping Sept. 15, 1990 and finished the first phase on
May 15.
Despite problems with a data recorder and a computer unit that
can knock the craft out of contact with Earth, Magellan mapped 84
percent of the surface when only 70 percent was expected, producing
images 10 times more detailed than anything previously.
``The Magellan spacecraft has given us an incredible global
view of the geology of Venus,'' Head said ``This is an incredible
laboratory for the study of an Earth-like planet.''
|
| 456.315 | Magellan Status - 5/30/91 | PRAGMA::GRIFFIN | Dave Griffin | Fri May 31 1991 11:56 | 31 |
| MGN REPORT 5/30
AJS
5-30-91
9:00 AM
MAGELLAN STATUS REPORT
1. Magellan spacecraft performance continues to be excellent.
2. All but two of the STARCALS yesterday were fully
successful. The spacecraft attitude knowledge remains
very precise.
3. The weekly command sequence M1150 was successfully
uplinked to the spacecraft yesterday and will begin
execution this afternoon.
4. This mapping sequence continues the two 55-minute hide
periods in each orbit and the right hand, constant look
angle mapping in order to map the south pole.
5. The mapping sequence alternates between immediate and
delayed swaths. The "immediate" swaths begin at about
45 degrees south latitude and extend to 73 degrees south.
The "delayed" swaths begin at 69 degrees south latitude
and end at the pole.
|
| 456.316 | Magellan Status Report - 05/31/91 | PRAGMA::GRIFFIN | Dave Griffin | Mon Jun 03 1991 12:12 | 29 |
|
AJS
5-31-91
9:00 AM
MAGELLAN STATUS REPORT
1. The Magellan spacecraft and radar system are performing
nominally.
2. The spacecraft started execution of the M1150 sequence
yesterday with Orbit #2270. This morning at about 9:00 AM
PDT controllers will uplink an update to the Radar Control
Parameter File.
3. The current mapping sequence includes two 55-minute hide
periods in each orbit and offpointing of the solar panels
for thermal control. The adverse thermal environment will
continue until mid-July and we will not return to full
mapping swaths until July 24th.
4. The sequence also continues the right hand, constant look
angle radar mapping in order to map the south pole. So
far, we've mapped 1/2 of 1% of the surface in the right
look mode. (See attached coverage map.)
|
| 456.317 | Magellan Status Report - 06/03/91 | PRAGMA::GRIFFIN | Dave Griffin | Mon Jun 03 1991 19:50 | 29 |
| AJS
6-03-91
9:00 AM
MAGELLAN STATUS REPORT
1. The Magellan spacecraft is continuing to perform
nominally. Only one star reject was counted during the
weekend, so the STARCALs and DESATs continue to be very
successful.
2. This morning spacecraft controllers are uplinking a
software patch to correct the timing problem in which the
mapping sequence would not allow a mapping swath to start
after the time of periapsis.
3. Since we are currently operating in a mode which includes
two 55-minute hide periods, and using a right look radar
approach in order to map area around the South Pole, all
of the mapping swaths begin after periapsis (the lowest
point of the orbit).
4. As of 10:00 AM PDT, Magellan is in its 80th orbit of right
hand mapping. But since each mapping pass is shortened to
about 9 minutes, the area covered is about equal to 12
full mapping swaths.
|
| 456.318 | Magellan Status Reports - 06/05/91, 06/07/91 | PRAGMA::GRIFFIN | Dave Griffin | Sun Jun 09 1991 15:01 | 79 |
| MGN REPORT 6/5
AJS
6-05-91
9:00 AM
MAGELLAN STATUS REPORT
1. The Magellan spacecraft and its radar system are
performing nominally.
2. Later today (at 1:45 PM PDT) the M1156 command sequence
will begin execution aboard Magellan. It will continue
the right-look mapping of the extreme southern area and
will include two 55-minute hide periods in each orbit.
3. Magellan has now completed 1823 mapping orbits, 96 since
the radar operation was switched to right-hand mapping.
MAGELLAN STATUS REPORT June 5, 1991
The Magellan spacecraft and its radar system are performing
normally.
The spacecraft today begins execution of a new command
sequence that will continue the right-look mapping of the extreme
southern area of Venus. It also includes two 55-minute periods in
each orbit in which the spacecraft hides from the sun behind its
high-gain antenna.
Magellan has completed 96 orbits since the radar operation
was switched from left to right-hand mapping. It has completed a
total of 1,823 mapping orbits since last Sept. 15.
Because of the high thermal environment caused by the
geometry of Venus, Earth and the sun, there are only nine minutes
of mapping in each orbit. Mapping swaths range from 45 degrees
south latitude to the south pole.
MGN REPORT 6/7
AJS
6-07-91
9:00 AM
MAGELLAN STATUS REPORT
1. The Magellan spacecraft and radar system are performing
nominally. All STARCALs and DESATs yesterday were
successful.
2. Today controllers will uplink an update to the Radar
Control Parameter File.
3. The current mapping sequence includes two 55-minute hide
periods in each orbit and offpointing of the solar panels
for thermal control. We'll have twenty more days of this
mode. Then Magellan will switch to left-look mapping and
two 30-minute hide periods, as we fill in one of the major
gaps in the Cycle 1 coverage.
4. This so-called "Superior Conjunction Gap" occurred last
fall when the sun got between the Earth and Venus, forcing
us to suspend radar mapping for 15 days. It represents
6.2% of the Venus surface, and we expect to recover about
5% during the period between June 27 and July 12.
5. We can't get it all because of the continuing thermal
environment which requires the two 30-minute cooling-off
periods in each orbit.
|
| 456.319 | Magellan Status Report - 06/10/91 | PRAGMA::GRIFFIN | Dave Griffin | Mon Jun 10 1991 21:47 | 24 |
| MGN REPORT 6/10
AJS
6-10-91
9:00 AM
MAGELLAN STATUS REPORT
1. The Magellan spacecraft is continuing to perform
nominally. Only one star reject was counted during the
weekend, so the STARCALs and DESATs continue to be very
successful.
2. We are currently operating in a mode which includes two
55-minute hide periods, and using a right look radar
approach in order to map area around the South Pole.
3. As of 10:00 AM PDT, Magellan is in its 131st orbit of
right hand mapping. But since each mapping pass is
shortened to about 9 minutes, the area covered is about
equal to 21 full mapping swaths.
|
| 456.320 | Magellan Status Report - 06/12/91 | PRAGMA::GRIFFIN | Dave Griffin | Thu Jun 13 1991 14:01 | 20 |
| MAGELLAN STATUS REPORT
June 12, 1991
The Magellan spacecraft and its radar system are performing
normally. All star calibrations and momentum wheel desaturations
were successful except for one star reject.
The weekly command sequence was sent to the spacecraft
Tuesday and begins execution today. It continues the two 55-
minute hide periods for thermal control and mapping of the area
from 45 degrees south latitude to the south pole.
The present mapping mode will continue through the current
sequence. Next week controllers will shift again to left-looking
radar mapping and 32-minute periods hiding behind the high-gain
antenna. Magellan will then begin to fill in the superior
conjunction gap, the area not mapped in the first cycle when
Earth and Venus were on opposite sides of the sun.
|
| 456.321 | Magellan Status Report - 6/13/91, 6/14/91 | PRAGMA::GRIFFIN | Dave Griffin | Mon Jun 17 1991 12:44 | 53 |
| MGN REPORT 6/13
AJS
6-13-91
9:00 AM
MAGELLAN STATUS REPORT
1. Magellan spacecraft performance continues to be excellent.
2. All STARCALs and DESATs yesterday were fully successful.
3. Today spacecraft controllers are updating some of the fault
protection parameters, and tomorrow they will perform the
routine update to the Radar Control Parameter File.
4. Magellan is now in its 1881st mapping orbit, the 154th since
we switched to right-look mapping. Venus has turned 400
degrees on its axis since we started mapping on September 15,
1990.
MGN REPORT 6/14
AJS
6-14-91
9:00 AM
MAGELLAN STATUS REPORT
1. Magellan Spacecraft subsystems continue to perform well.
2. Several STARCALS have been partly successful or have
failed due to large solar storms now occurring on the Sun.
3. Sequence 1163 rotated the Spacecraft 170o about the z-axis
during the "hide" manuevers when the Spacecraft is cooled
by using the high gain antenna. An error in the gyro bias
gains was discovered after the sequence began resulting
from not accounting for the 170o roll. This resulted in
gradually corrupting the gyro bias values on-board.
4. The result of the incorrect bias gains and solar activity
will result in 11 orbits having degraded pointing so far.
It is believed we will achieve accuracy pointing by 4:00
PM PDT.
|
| 456.322 | Magellan Status Report - 06/17/91 | PRAGMA::GRIFFIN | Dave Griffin | Mon Jun 17 1991 21:07 | 26 |
| MGN REPORT 6/17
AJS
6-17-91
9:00 AM
MAGELLAN STATUS REPORT
1. The Magellan spacecraft is continuing to perform
nominally.
2. Electrical power was down in the Denver Mission Support
area so subsystem engineers are still checking the
engineering telemetry from the weekend.
3. The star invalid counter incremented by only three,
indicating that most STARCALs and DESATs continue to be
very successful.
4. Magellan is currently operating in a mode which includes
two 55-minute hide periods, and using a right look radar
approach in order to map area around the South Pole. This
will continue for the next ten days.
|
| 456.323 | MAGELLAN Update - June 19 | JVERNE::KLAES | All the Universe, or nothing! | Thu Jun 20 1991 13:52 | 36 |
| Article 14478
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.astro
Subject: Magellan Update - 06/19/91
Date: 20 Jun 91 07:35:05 GMT
Sender: nobody@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory
Crossposted by: Ron Baalke from NASAMAIL P board
(All NASAMAIL board P items are O.K. for unlimited distribution per JPL PIO,
unless the postings indicate otherwise)
MAGELLAN STATUS REPORT
June 19, 1991
The Magellan spacecraft and its radar system are performing
normally. All star calibrations and momentum wheel desaturations were
successful.
The weekly command sequence was uplinked to the spacecraft
Tuesday and begins execution today. It continues the two 55-minute
periods in each orbit of hiding behind the high-gain antenna for
thermal control and mapping of the area from 45 degrees south latitude
to the south pole.
Next week's sequence will shift again to left-looking radar
mapping, and reduce the hide periods to 32 minutes each as controllers
begin to fill in the superior conjunction gap, the area not mapped in
the first cycle when Earth and Venus were on opposite sides of the Sun.
_____
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 301-355 | "Imagination is more
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | important than knowledge"
|_____|/ |_|/ |_____|/ | Albert Einstein
|
| 456.324 | MAGELLAN Update - June 20 | JVERNE::KLAES | All the Universe, or nothing! | Mon Jun 24 1991 19:31 | 29 |
| Article 32491
From: ejbehr@rs6000.cmp.ilstu.edu (Eric Behr)
Newsgroups: sci.space
Subject: Magellan status report
Date: 22 Jun 91 23:58:37 GMT
Organization: Central Illinois Surfing Club
MGN REPORT 6/20
AJS
6-20-91
9:00 AM
MAGELLAN STATUS REPORT
1. Magellan spacecraft performance continues to be excellent.
2. All STARCALs and DESATs yesterday were successful except
for one star reject on orbit #2415.
3. Tomorrow spacecraft controllers will perform the routine
update to the Radar Control Parameter File.
4. Magellan is now in its 1934th mapping orbit, with over 200
since we switched to right-look mapping.
--
Eric Behr, Illinois State University, Mathematics Department
Internet: ejbehr@rs6000.cmp.ilstu.edu Bitnet: ebehr@ilstu
|
| 456.325 | Venus laval flow may be similar to current earth eruptions | PRAGMA::GRIFFIN | Dave Griffin | Mon Jul 01 1991 14:10 | 60 |
| RELEASE: 91-100 (6/28/91)
The Magellan spacecraft, mapping the surface of Venus with
imaging radar, has discovered a lava flow that may represent a
volcanic eruption similar to those currently taking place in Japan
and the Philippines, a Magellan scientist said.
Dr. James Head of Brown University, a geologist on the
Magellan science team, said the spacecraft has been mapping a
planet dominated by volcanism. Large volcanoes, long lava flows
and rivers of lava have formed on the surface of Earth's nearest
planetary neighbor and may be continuing to form today, Head said.
Unusual volcanoes with petal-shaped flows have been imaged
which are different from most other volcanoes on Venus. The lack
of weathering or erosion due to lack of water on Venus allows
scientists to view a whole preserved sequence of volcanism, Head
said.
"For most volcanoes, we don't understand how the molten rock
gets out of the ground because we can't see below the surface," he
said. "On Venus, however, the relationships between the volcanoes
and the tectonic fractures will help us understand the way in
which molten rock gets out of the interior."
A recently discovered flow found in a highly fractured region
may be significant in telling Magellan scientists where and how
melting of rock is taking place in the interior of the planet, he
said.
"This deposit may represent an eruption like those that are
currently happening in Japan and the Philippines," Head said. "On
Earth, the atmospheric pressure is such that when the gas-rich
molten material reaches the surface, the resulting eruption sends
the material up into the atmosphere in plumes, spreading it over
large areas as it falls out of the atmosphere.
"On Venus, the surface atmospheric pressure is about 90 times
higher than on Earth and when the gas-rich molten material reaches
the surface, it may not form into plumes, but instead may flow out
over the surface. Therefore, this may be an eruption like the one
in the Philippines, but changed in its style by the very different
conditions of the atmosphere," he said.
Magellan Project Scientist Dr. Steve Saunders said that over
the next several mapping cycles, Magellan will re-image several
volcanic regions with the same geometry as in the first mapping
cycle.
"By comparing the images, we should be able to detect changes
in the lava flows, indicating that a volcano has erupted and that
Venus is indeed geologically active like the Earth," Saunders
said.
A mapping cycle is 243 days, or one rotation of Venus on its
axis. The second mapping cycle began May 15. Magellan is managed
by the Jet Propulsion Laboratory for the Office of Space Science
and Applications, Washington, D.C.
- end -
|
| 456.326 | Magellan Status Reports (6/21-6/27) | PRAGMA::GRIFFIN | Dave Griffin | Mon Jul 01 1991 14:21 | 205 |
|
AJS
6-21-91
9:00 AM
MAGELLAN STATUS REPORT
1. The Magellan spacecraft is continuing to perform nominally
after 315 days of orbiting Venus.
2. Today controllers will update the Radar Control Parameter
File.
3. The current mapping sequence includes two 55-minute hide
periods in each orbit and offpointing of the solar panels
for thermal control. We'll have 4-1/2 more days of this
mode.
4. Then, on Wednesday, Magellan will switch to left-look
mapping and two 30-minute hide periods, as we fill in one
of the major gaps in the Cycle 1 coverage.
5. This so-called "Superior Conjunction Gap" occurred last
fall when the sun got between the Earth and Venus, forcing
us to suspend radar mapping for 15 days. It represents
6.2% of the Venus surface, and we expect to recover 4.8%
during the period between June 27 and July 12.
6. We can't get it all because of the continuing thermal
environment which requires the two 30-minute cooling-off
periods in each orbit.
------------------------------------------------------------------------------
AJS
6-24-91
9:00 AM
MAGELLAN STATUS REPORT
1. Magellan spacecraft is continuing to perform nominally
after 318 days of orbiting Venus. All but one star
calibration have been successful since Friday morning.
2. Today controllers will prepare the M1177 sequence
load which will switch to left-look mapping and two
32-minute hide periods, as we fill in one of the major
gaps in the Cycle 1 coverage. This sequence will be
uplinked tomorrow to take effect early Wednesday morning.
3. Current sequence includes two 55-minute hide periods in
each orbit and off-pointing of the solar panels for
thermal control. There is 2 more days of this mode.
4. This so-called "Superior Conjunction Gap" occurred last
fall when the Sun got between the Earth and Venus, forcing
us to suspend radar mapping for 15 days. It represents
6.2% of the Venus surface, and we expect to recover 4.8%
during the period between June 27 and July 12.
5. We can't get it all because of the continuing thermal
environment which requires the two 32-minute cooling-off
periods in each orbit.
------------------------------------------------------------------------------
AJS
6-25-91
9:00 AM
MAGELLAN STATUS REPORT
1. The Magellan spacecraft and its radar system are
performing nominally. All starcals and desats were
successful, with only one missed star.
2. The weekly command sequence M1177 will be sent to the
spacecraft later today. It will begin the recovery of the
so-called Superior Conjunction Gap, a portion of the Venus
surface which was missed last October when the sun got
between the Earth and Venus.
3. The radar will shift to the left-looking, variable
incidence angle mode, and will map the area from about 51x
North latitude to 45x South latitude.
4. The new sequence will include two 32-minute hide periods
and off-pointing of the solar panels for thermal control.
and mapping of the area from 45 degrees south latitude to
the South Pole.
5. Ellen Stofan was interviewed on Airtalk, a Caltech
television program with simultaneous radio broadcast, on
June 19. She described the Magellan mission and answered
questions.
6. On June 20 at JPL, Dr. Stofan gave a briefing on the use
of SAR in geology at the NASA Educational Workshop for
Math, Science and Technology Teachers, attended by
educators from all over the U.S.
7. Jeff Plaut spoke to the JPL Co-operative Education Program
students on the status of Magellan, the mission design,
and showed some recent images.
8. Steve Saunders participated in the joint Magellan/Pioneer
12 Science Briefing for the DSN station personnel in
Madrid, Spain on June 18-25. Dr. Saunders express the
Project's appreciation for the Madrid station personnel's
participation in making Magellan a successful mission, and
showed recent Magellan images and the latest video.
-----------------------------------------------------------------------------
MAGELLAN STATUS REPORT
June 26, 1991
The Magellan spacecraft and its radar system are performing
normally.
The weekly command sequence was uplinked to the spacecraft
Tuesday and began execution today. The sequence shifts the radar
to the left-looking mode and maps the area from 51 degrees north
latitude to 45 degrees south latitude. This begins to fill in the
superior conjunction gap from the first cycle. The gap is a
portion of the Venus surface which was missed last October when
the Earth and Venus were on opposite sides of the sun.
The new sequence also includes two 32-minute periods in each
orbit of hiding the spacecraft behind its high-gain antenna for
thermal control. Since the beginning of the second mapping cycle
May 16, and until today, the spacecraft has been put behind the
antenna for two 55-minute periods in each orbit while it was
mapping the far southern latitudes.
The hide periods also include pointing the solar panels
away to prevent too much reflected heat on the spacecraft bus.
_____
AJS
6-26-91
9:00 AM
MAGELLAN STATUS REPORT
1. The Magellan spacecraft and its radar system are
performing nominally.
2. The weekly command sequence M1177 was sent to the
spacecraft yesterday and began execution early this
morning at 1:48 AM PDT.
3. The sequence shifts the radar to the left-looking,
variable incidence angle mode, and maps the area from 51x
North latitude to 45x South latitude. This begins to fill
in the Superior Conjunction Gap, a portion of the Venus
surface which was missed last October when the sun got
between the Earth and Venus.
4. The new sequence also includes two 32-minute hide periods
and off-pointing of the solar panels for thermal control.
------------------------------------------------------------------------------
AJS
6-27-91
9:00 AM
MAGELLAN STATUS REPORT
1. Magellan spacecraft performance continues to be excellent.
2. The spacecraft is warming up since we switched from 55-
minute to 32-minute cooling-down periods. Bay 7 is at
50xC and the Rocket Engine Modules (REMs) are between 85
and 90xC.
3. Late today spacecraft controllers will perform the routine
update to the Radar Control Parameter File.
4. Magellan is now in its 1986th mapping orbit and is pre-
sently filling in the Superior Conjunction Gap. It has
completed 10 of the 110 orbits needed to fill the gap.
5. The area of Venus being imaged includes the Eisela Regio
(at the western end of Aphrodite) and Bell Regio (a pro-
|
| 456.327 | Magellan Status Reports (7/1/91, 7/2/91) | PRAGMA::GRIFFIN | Dave Griffin | Wed Jul 03 1991 13:16 | 49 |
|
AJS
7-01-91
9:00 AM
MAGELLAN STATUS REPORT
1. Magellan spacecraft performance continues to be excellent.
2. The 32-minute cooling periods continue. Bay 7 is at 50xC
and the Rocket Engine Modules (REMs) are between 85 and
90xC.
3. Spacecraft controllers performed the routine update to
the Radar Control Parameter File on Thursday.
4. Magellan is now in its 2503rd mapping orbit and is pre-
sently filling in the Superior Conjunction Gap. It has
completed 39 of the 110 orbits needed to fill the gap.
AJS
7-02-91
9:00 AM
MAGELLAN STATUS REPORT
1. Magellan spacecraft performance continues to be excellent.
2. The 32-minute cooling periods continue. Bay 7 is at 50xC
and the Rocket Engine Modules (REMs) are between 85 and
90xC.
3. Spacecraft controllers performed the routine update to
the Radar Control Parameter File on Thursday.
4. Magellan is now in its 2511th mapping orbit and is pre-
sently filling in the Superior Conjunction Gap. It has
completed 47 of the 110 orbits needed to fill the gap.
5. Planning to send the three command files to correct
Runaway Program Execution (RPE) anomaly which has occurred
5 times in the past causing loss of science data.
|
| 456.328 | More Magellan images | PRAGMA::GRIFFIN | Dave Griffin | Fri Jul 05 1991 03:04 | 6 |
| 16 new Magellan images are now available - bringing our total to 61
images from Magellan.
pragma::public:[nasa]MGN_*.gif. Check the dates for the latest files.
- dave
|
| 456.329 | Magellan Status Report - 07/08/91 | PRAGMA::GRIFFIN | Dave Griffin | Tue Jul 09 1991 21:55 | 23 |
| Forwarded from Anthony Spear, Magellan Project Manager
MAGELLAN STATUS REPORT
July 8, 1991
1. The Magellan spacecraft is continuing to perform
nominally.
2. All STARCALs and DESATs over the four day weekend were
successful, with only one missed star.
3. The spacecraft is currently operating in a mode which
includes two 30-minute hide periods, and a left-look radar
approach in order to map the area which was missed during
Superior Conjunction last fall. So far we have completed
92 of the 125 orbits planned for this phase.
4. Magellan is in its 2067th mapping orbit at Venus.
********************************************************************
Glenn S. Johnson, NASA's Jet Propulsion Laboratory
Internet: johnson@kelvin.jpl.nasa.gov, gjohnson@coil.cco.caltech.edu
X.400:(C:USA, ADMD:TELEMAIL, PRMD:NASAMAIL, O:NASA, UN:GSJOHNSON)
|
| 456.330 | Magellan Status - July 10-16th | PRAGMA::GRIFFIN | Dave Griffin | Tue Jul 16 1991 21:51 | 158 |
| MAGELLAN STATUS REPORT July 10, 1991
The Magellan spacecraft and its radar system are performing
normally, completing the 2083rd mapping orbit of Venus this
morning.
The current mapping sequence, begun last week and running to
Friday this week, consists of 123 orbits with the radar looking
to the left. Magellan is mapping the gap caused last October at
superior conjunction, when the Sun was between the spacecraft and
Earth and interrupted communications. Mapping the south polar
regions of Venus, with the radar looking to the right, will
resume Friday afternoon.
The spacecraft continues to hide behind its high-gain
antenna and to turn its solar panels to minimize solar heating of
the spacecraft bus and radar compartment. However, the hiding
requirement is down to two 30-minute periods each orbit, and is
declining rapidly as the orbit moves into the shadow of Venus.
#####
MGN REPORT 7/10
AJS
7-10-91
9:00 AM
MAGELLAN STATUS REPORT
1. The Magellan spacecraft and its radar system are
performing nominally. All starcals and desats were
successful, with only one missed star.
2. The spacecraft continues to operate in a mode of left-
looking radar in order to map the area which was missed
during Superior Conjunction last fall.
-----------------------------------------------
AJS
7-11-91
9:00 AM
MAGELLAN STATUS REPORT
1. Magellan spacecraft performance continues to be excellent.
2. Yesterday spacecraft controllers performed the routine
update to the Radar Control Parameter File. Late today
they will uplink the M1193 command sequence which will
return Magellan to right-look, constant incidence angle
mapping.
3. Magellan will perform a high resolution imaging test
during five orbits on Friday. Changes to the radar
control parameters are expected to increase the resolution
at periapsis from 120 to 60 meters. If the test is
successful, the high resolution approach may be used on
radar mapping in Cycle #3 early next year.
4. The past two weeks have added about 4.8% to Venus surface
area mapped by Magellan, bringing the total to 88.7%.
-------------------------------------------------------------------------
AJS
7-12-91
9:00 AM
MAGELLAN STATUS REPORT
1. Magellan spacecraft performance continues to be excellent.
2. Engineering telemetry indicated two spurious shutoffs
(SSO) of the TWTA late yesterday. They occurred about
3:15 PM PDT and the spacecraft was back in normal
communications at 3:23 PM. The spacecraft team is
planning to perform a memory readout later today to
further analyze the SSOs.
3. The spacecraft is presently performing a high resolution
imaging test. As the radar system continues to map Venus,
changes have been made to the radar control parameters to
increase the resolution at periapsis from 120 to 60
meters. The test will end at 3:22 PM PDT today.
4. At 3:27 PM today the M1193 sequence will begin execution.
It returns to the right-look radar mapping, with 38
minutes hide periods for thermal control. The next week's
mapping will cover the area from 20 degrees south latitude
to the South Pole.
5. With the completion of the "Superior Conjunction Gap Fill"
today, Magellan has mapped 88.8% of the Venus surface.
(See attached chart.)
----------------------------------------------------------------------------
AJS
7-15-91
9:00 AM
MAGELLAN STATUS REPORT
1. Magellan spacecraft and its radar system are performing
nominally. All starcals and desats were successful
over the weekend.
2. At 3:27 PM last Friday the M1193 sequence began execution.
It returned to right-looking radar mapping, with 38-minute
hide periods for thermal control.
3. The spacecraft team has performed a memory readout and
additional recorded data is being analyzed to investigate
last weeks spurious shutoffs (SSO) on the TWTA.
----------------------------------------------------------------------------
AJS
7-16-91
9:00 AM
MAGELLAN STATUS REPORT
1. The Magellan spacecraft and its radar system are
performing nominally. All starcals and desats were
successful.
2. The spacecraft is currently operating in a mode which
includes two 38-minute hide periods, and right-look radar
mapping of the are from 20 degrees south latitude to the
South Pole.
3. The star tracker unit has registered some miscompares from
expected star counts, presently over 30 per orbit. This
is believed to be caused by the albedo of the planet and
the current mapping geometry.
4. Later today controllers will update the Radar Control
Parameter File.
5. Magellan is now in its 2126th mapping orbit; 1852 left-
looking and 274 right-looking.
|
| 456.331 | | DECWIN::FISHER | Klingons don't "enter a relationship"...they conquer | Wed Jul 17 1991 15:33 | 4 |
| How come on the tenth they were doing 30-minute hide periods and the
need was declining rapidly, and then they went to 38-minute periods?
Burns
|
| 456.332 | The ballet has changed... | PRAGMA::GRIFFIN | Dave Griffin | Wed Jul 17 1991 15:45 | 4 |
| The approach was changed from left-look to right-look - which probably
has different thermal characteristics.
- dave
|
| 456.333 | | DECWIN::FISHER | Klingons don't "enter a relationship"...they conquer | Thu Jul 18 1991 15:26 | 3 |
| Ah...of course. Thanks.
Burns
|
| 456.334 | MAGELLAN Update - July 18 | JVERNE::KLAES | All the Universe, or nothing! | Fri Jul 19 1991 14:21 | 78 |
| Article 15262
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 07/18/91
Date: 19 Jul 91 00:15:31 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from Anthony Spear, Magellan Project Manager
MAGELLAN STATUS REPORT
July 18, 1991
Magellan spacecraft performance continues to be excellent.
Yesterday, spacecraft controllers performed an update to the Kalman
Gains in preparation for a change of the star pair used during the
STARCALs (star calibrations). Late today, they will uplink the M1201
command sequence which will continue the right-look, constant
incidence angle mapping.
The new command sequence will reduce the two hide periods to 14
minutes each. This will allow the radar mapping to cover the area
from about 15 degrees north latitude to the South Pole.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 301-355 | "Computers are useless.
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | They can only give you
|_____|/ |_|/ |_____|/ | answers." Pablo Picasso
Article 15267
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.astro
Subject: Magellan Update #2 - 07/18/91
Date: 19 Jul 91 01:19:35 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from NASAMAIL P
MAGELLAN STATUS REPORT
July 18, 1991
The Magellan spacecraft and its radar system are performing
normally, and completed the 2135th mapping orbit Wednesday afternoon.
The system is once again mapping the southern part of Venus, from
20 degrees South to the South Pole. The radar is looking to the
right, and there is a moderate overlap with areas mapped 8 months ago.
For two 38-minute periods each orbit, the spacecraft hides behind its
high-gain antenna to keep spacecraft and radar electronics
compartments from overheating. The need for cooling periods will
diminish over the next few weeks until Magellan is able to map from 75
degrees North to the South Pole.
Last Thursday, the X-band transmitter used for radar data
playbacks to Earth was shut down twice by spurious internal signals.
The spacecraft detected and automatically corrected these faults and
restored normal transmission in about 5 minutes. The S-band command
and telemetry communications were not affected.
Last Friday Magellan successfully tested modified radar control
software designed to improve surface resolution by a factor of two.
Obtaining actual images from the test run requires special processing
software and will occur in a few weeks. When this system is
incorporated in a later sequence, the radar will be able to resolve
surface features half as wide as before.
#####
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 301-355 | "Computers are useless.
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | They can only give you
|_____|/ |_|/ |_____|/ | answers." Pablo Picasso
|
| 456.335 | MAGELLAN Update - July 19 | JVERNE::KLAES | All the Universe, or nothing! | Mon Jul 22 1991 21:00 | 36 |
| Article 15288
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 07/19/91
Date: 19 Jul 91 21:30:32 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from Anthony Spear, Magellan Project Manager
MAGELLAN STATUS REPORT
July 19, 1991
Magellan spacecraft performance continues to be excellent. Attitude
updates following the star calibrations are averaging 0.018 degree.
Spacecraft controllers missed the first command window for the M1201
sequence due to problems at DSN (Deep Space Network) station 65 (Madrid 34
meter station), but they are confident that the uplink will be completed well
before the command sequence is due to go active tomorrow morning at 6:05 AM
PDT.
The new command sequence will reduce the two hide periods to 14 minutes
each. This will allow the radar mapping to cover the area from about 15
degrees north latitude to the South Pole.
As of noon (PDT) today Magellan has completed 2147 mapping orbits of
Venus, imaging about 90% of the surface area.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 301-355 | "Computers are useless.
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | They can only give you
|_____|/ |_|/ |_____|/ | answers." Pablo Picasso
|
| 456.336 | MAGELLAN Update - July 22 | RBURNS::KLAES | All the Universe, or nothing! | Tue Jul 23 1991 16:02 | 43 |
| Article 15339
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 07/22/91
Date: 23 Jul 91 04:16:21 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from Anthony Spear, Magellan Project Manager
MAGELLAN STATUS REPORT
July 22, 1991
The Magellan spacecraft is continuing to perform nominally. All
STARCALs (star calibrations) and DESATs (desaturations of the reaction
wheels) over the weekend were successful.
The spacecraft is currently operating in a mode which includes
two 14-minute hide periods, and a right-look radar approach which maps
the area from about 15 degrees north latitude to the South Pole.
The spacecraft also spends more that a half hour of each orbit in
the shadow of Venus (i.e. in solar occultation). This has resulted in
a slight lowering of electrical power on the main spacecraft bus, so
the controller are preparing to ending the solar panel offpoint.
Commands will be sent later today to point the panels directly at the
Sun.
Antenna problems at the DSS 65 (34 meter Canberra station) over
the weekend resulted in the loss of radar and telemetry data from
several orbits. It is estimated that all data was lost from orbit
#2649 on Sunday, and that at least half of orbits 2656 and 2657 were
lost this morning.
Magellan is in its 2169th mapping orbit at Venus.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 301-355 | "Computers are useless.
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | They can only give you
|_____|/ |_|/ |_____|/ | answers." Pablo Picasso
|
| 456.337 | MAGELLAN Update - July 23 | JVERNE::KLAES | All the Universe, or nothing! | Tue Jul 23 1991 19:46 | 42 |
| Article 15355
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 07/23/91
Date: 24 Jul 91 01:05:56 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from Anthony Spear, Magellan Project Manager
MAGELLAN STATUS REPORT
July 23, 1991
The Magellan spacecraft and its radar system are performing nominally.
All starcals (star calibrations) and desats (desaturations) were successful,
with only one missed star.
The spacecraft is currently operating in a mode which includes two
14-minute hide periods, and right-look radar mapping of the area from 14
degrees north latitude to the South Pole.
Tomorrow, the radar mapping will shift to left-looking for several orbits
to perform a test of stereo radar imaging. Then the mapping will return to
right-look radar.
The spacecraft now passes thru the shadow of Venus at apoapsis. This has
resulted in some lowering of the voltage on the main spacecraft electrical
power bus. It is presently 26 volts with a cycle depth of 21%. Spacecraft
controllers have prepared contingency commands to reduce the solar panel
offpoint to zero.
[Round trip light time to Magellan is 6 minutes, 42 seconds. The spacecraft
is now mapping the area along the eastern end of Ishtar Terra, through
the center of Leda Planitia and the west end of Aphrodite Terra. - Ron Baalke]
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 301-355 | "Computers are useless.
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | They can only give you
|_____|/ |_|/ |_____|/ | answers." Pablo Picasso
|
| 456.338 | MAGELLAN Update - July 24 | JVERNE::KLAES | All the Universe, or nothing! | Wed Jul 24 1991 18:47 | 52 |
| Article 15374
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 07/24/91
Date: 24 Jul 91 21:40:10 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from Anthony Spear, Magellan Project Manager
MAGELLAN STATUS REPORT
July 24, 1991
The Magellan spacecraft and its radar system are performing
nominally. All starcals (star calibrations) and desats (desaturations)
yesterday were successful.
Late yesterday the TWTA-A (the high power amplifier) experienced
its 11th Spurious Shutoff (SSO) since the mission began. It was
automatically powered on and normal operation restored within five
minutes.
The spacecraft is currently operating in a mode which includes
two 14-minute hide periods, and right-look radar mapping of the area
from 14 degrees north latitude to the South Pole.
The spacecraft electrical power bus presently reaches a low of
26 volts with a cycle depth of 21%. Spacecraft controllers are
monitoring the power levels closely and have prepared contingency
commands to reduce the solar panel offpoint to zero.
At 11:30 AM PDT today the radar mapping will shift to
left-looking for eight orbits to perform a test of stereo radar
imaging. Then the mapping will return to right-look radar.
The M1207 command sequence will be uplinked late tomorrow. This
will be the first two-week sequence, and marks a return to full
mapping swaths.
No hide periods are required in the next sequence partly due to
increasing periods of solar occultation and also the use of a
spacecraft flip-flop maneuver for thermal control.
[Round trip light time to Magellan is now at 6 minutes, 35 seconds - RB]
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 301-355 | "Computers are useless.
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | They can only give you
|_____|/ |_|/ |_____|/ | answers." Pablo Picasso
|
| 456.339 | MAGELLAN Update - July 25; future radar plans | JVERNE::KLAES | All the Universe, or nothing! | Fri Jul 26 1991 15:09 | 109 |
| Article 15414
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 07/25/91
Date: 26 Jul 91 07:09:18 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from Anthony Spear, Magellan Project Manager
MAGELLAN STATUS REPORT
July 25, 1991
The Magellan spacecraft and its radar system are performing
nominally. All starcals and desats yesterday were successful.
The spacecraft is currently performing an 8-orbit stereo radar
test, which will conclude at 1:30 PM PDT today. Then the mapping will
return to right-look radar.
The test is to determine if steroscopic pairs of images can be
produced. Data from these orbits is being collected in a left-looking
mode, but at a different incidence angle than when the same area was
mapped during Cycle 1.
The spacecraft electrical power bus reached a low of 25.7 volts
during the first orbit of the stereo test. This is partly due to
increased use of the battery heaters during solar occultation and the
use of catalyst bed heaters during that orbit for the reaction wheel
desaturation.
Spacecraft controllers are continuing to monitor the power levels
closely and sent up commands to change the on-board VvT curve. The
bus voltage has remained above 26 volts since.
The M1207 command sequence will be uplinked late today. This
will be the first two-week sequence, and marks a return to full
mapping swaths. No hide periods are required partly due to increasing
periods of solar occultation and also the use of a spacecraft
"flip-flop" maneuver for thermal control.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 301-355 | "Computers are useless.
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | They can only give you
|_____|/ |_|/ |_____|/ | answers." Pablo Picasso
Article 15429
From: pgf@space.mit.edu (Peter G. Ford)
Newsgroups: sci.astro
Subject: Re: MAGELLAN spacecraft
Date: 26 Jul 91 04:59:48 GMT
Sender: news@athena.mit.edu (News system)
Organization: MIT Center for Space Research
In article <1991Jul26.024054.10967@uokmax.ecn.uoknor.edu>
rwmurphr@uokmax.ecn.uoknor.edu (Robert W Murphree) writes:
>Dear Ron Baalke or someone in the know:
>Due to breakdown in communications, I never found out whether the JPL
>people ever fixed the broken tape recorder and what the offshoot of
>this problem were for the extended mission.
Tape recorder A remains broken--it seems to record properly but
scrambles the bits during playback. It has undergone several tests
during which the tape was erased many times, written and read back at
varying speeds, etc., but the consensus is that there is a hardware
failure in the play-back electronics, and there is very little hope of
recovery.
The remaining recorder is able to store a full orbit of radar data on
its 4 tracks, but it takes a few seconds to switch from one track to
another, so this introduces small gaps in the data, leading to
regularly spaced patches of missing data in the Magellan images. The
"mean" lifetime of this model of recorder is determined by the number
of times it must start and stop--apparently, there is a spring that
usually breaks first, and it is good for an average of several
thousand operations before it "pops". I don't know the precise
statistics, but this is a popular "NASA standard" unit and the
mean-time-between-failures is equivalent to about another year of
operation in the current mode.
Without a recorder, synthetic aperture radar mapping is OUT, but
several other experiments are possible. With or without aerobraking
(using atmospheric drag to move Magellan to a low circular orbit), the
gravity experiment would go ahead--with the high-gain antenna turned
toward Earth. It may also be possible to re-program the command and
data system to record a small quantity of data, e.g. radiometry or
high-resolution altimetry, in semi-conductor memory, transmitting it
back to Earth in the same manner as at present.
Another possible experiment would angle to high-gain antenna so as to
reflect radar waves off the Venus surface and receive them on Earth,
e.g. at the Arecibo Observatory whose 305 meter dish and 2380 Mhz
receiver system could detect Magellan's 2385 Mhz signal with trivial
modification. Such a "bistatic" experiment is complimentary to the
present Magellan observations in which the angles of incidence and
reflection are always identical and only one polarization component is
observed.
So there are lots of things that can be done without a tape recorder,
and contingency plans are being made, but everybody hopes that we
don't have to resort to them for a few years yet.
Peter Ford
MIT and Magellan Project
|
| 456.340 | New Magellan Radar Images of Venus Released | PRAGMA::GRIFFIN | Dave Griffin | Mon Jul 29 1991 12:02 | 51 |
| RELEASE: 91-120 (7/26/91)
By the end of July the Magellan spacecraft will have
circled Venus 2,351 times and will have traveled 75 million
miles around the planet in its mapping mission, said
Magellan Project Scientist Dr. Steve Saunders.
One complete circuit of Venus takes eight months, the
length of one Venus day. Magellan is in the second of at
least seven planned cycles in which it will continue to
observe the complex surface of Venus.
Magellan has collected radar images of nearly 90
percent of the planet thus far. The data set is double the
amount of all other image data collected in the U.S.
planetary program to date, Saunders said.
With each day's images the Magellan scientists have an
opportunity to search the data for evidence of volcanic
activity by comparing new images with those taken eight
months previously during the first cycle.
"Just as on Earth, it is very likely that somewhere on
the planet a volcano is erupting at any given time; the
problem is to find it," Saunders said.
Venus has been revealed as a planet with at least as
complex a geologic record as Earth, with many of the same
geologic processes revealed on its surface, he said.
Volcanism is the dominant process, seen in many forms on
the plains.
"Volcanism, the eruption of molten rock onto the
surface, and tectonism, or faulting and folding of crustal
rocks, on Venus act much like erosion by running water on
Earth to modify the landscape," he said.
"We see evidence of continuing volcanism and tectonism
everywhere on the planet, in the vast lava floods and the
fractures, faults and ridge belts of the volcanic plains."
He added that fractured and faulted older terrains
also are seen. Tessera, a term for highly fractured
terrains, probably represent the oldest rocks, but the
deformation that has so completely distorted them appears
to be continuing at present.
"Now the search by Magellan continues for evidence
that Earth's sister planet remains today as violent as the
images suggest it has been in the recent past," Saunders
said.
|
| 456.341 | MAGELLAN Update - July 26 | MTWAIN::KLAES | All the Universe, or nothing! | Mon Jul 29 1991 12:49 | 31 |
| Article 15463
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 07/26/91
Date: 27 Jul 91 04:49:00 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from Anthony Spear, Magellan Project Manager
MAGELLAN STATUS REPORT
July 26, 1991
Magellan spacecraft performance continues to be excellent. Attitude
updates following the star calibrations are averaging 0.023 degree.
Yesterday, spacecraft controllers uplinked the M1207 command sequence.
This will be the first two-week sequence, and marks a return to full mapping
swaths. These are the first full mapping swaths in the right-look mode.
No hide periods are required partly due to increasing periods of solar
occultation and also the use of a spacecraft "flip-flop" maneuver for thermal
control.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 301-355 | "Computers are useless.
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | They can only give you
|_____|/ |_|/ |_____|/ | answers." Pablo Picasso
|
| 456.342 | MAGELLAN Update - July 29 | MTWAIN::KLAES | All the Universe, or nothing! | Tue Jul 30 1991 11:08 | 41 |
| Article 15518
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 07/29/91
Date: 30 Jul 91 01:06:27 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from Anthony Spear, Magellan Project Manager
MAGELLAN STATUS REPORT
July 29, 1991
The Magellan spacecraft is continuing to perform nominally. All STARCALs
(star calibrations) and DESATs (desaturations) over the weekend were
successful, with only one missed star.
The spacecraft is currently operating in a mode which uses a flip-flop
cooling strategy, and a right-look radar approach which maps the area from
about 75 degrees north latitude to the South Pole.
The spacecraft also spends more that a 40 minutes of each orbit in the
shadow of Venus (i.e. in apoapsis solar occultation). This has resulted in the
electrical power dipping below the nominal 26 volts occasionally. For example,
on orbit #2705 yesterday the bus voltage dipped to 25.7 volts and the cycle
depth was 26.5%. This may be corrected by disabling the battery heaters during
apoapsis occultation.
On Friday, there was another TWTA (X-Band transmitter) spurious shutoff
(SSO). The telecommunications analysts are studying the events to further
understand and possibly reduce the frequency of SSOs.
Magellan is now twelve days from completing its first year in Venus orbit.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 301-355 | "Computers are useless.
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | They can only give you
|_____|/ |_|/ |_____|/ | answers." Pablo Picasso
|
| 456.343 | MAGELLAN Update - July 30 | MTWAIN::KLAES | All the Universe, or nothing! | Wed Jul 31 1991 14:31 | 42 |
| Article 15573
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 07/30/91
Date: 31 Jul 91 05:07:24 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from Anthony Spear, Magellan Project Manager
MAGELLAN STATUS REPORT
July 30, 1991
The Magellan spacecraft and its radar system are performing
nominally. The electrical bus voltage continues to dip to 25.7 volts
during the Sun occultation portion of each orbit. The limit were load
shedding occurs is 24.5 volts.
Yesterday, the routine update to the Radar Control Parameter File
was sent to the spacecraft. No commanding is scheduled for today.
The spacecraft is currently operating in a mode which uses a
flip-flop cooling strategy, and a right-look radar approach which maps
the area from about 75 degrees north latitude to the South Pole.
Although we are back to full mapping swaths, only about 12
degrees latitude of each 165 degree swath represents new surface area.
Most of the area being covered for the next two months will overlap
the Cycle 1 data providing another perspective and the potential for
opposite side stereo.
About mid-September we will pick up some area lost in Cycle 1 due
to the degradation of tape recorder A and occulted mapping. At that
time we will pass the 90% mark in Venus area coverage.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 301-355 | "Computers are useless.
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | They can only give you
|_____|/ |_|/ |_____|/ | answers." Pablo Picasso
|
| 456.344 | MAGELLAN Update - July 31 | MTWAIN::KLAES | All the Universe, or nothing! | Thu Aug 01 1991 13:47 | 30 |
| Article 15617
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 07/31/91
Date: 1 Aug 91 09:16:16 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from Anthony Spear, Magellan Project Manager
MAGELLAN STATUS REPORT
July 31, 1991
The Magellan spacecraft is performing nominally. All starcals
and desats yesterday were successful.
Later today, controllers will send up the "Tweak," the weekly
update to the command sequence.
The spacecraft is continues to operate in a mode which uses a
flip-flop cooling strategy, and full mapping swaths from about 75
degrees north latitude to the South Pole.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 301-355 | "Computers are useless.
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | They can only give you
|_____|/ |_|/ |_____|/ | answers." Pablo Picasso
|
| 456.345 | MAGELLAN Update - August 1 | MTWAIN::KLAES | All the Universe, or nothing! | Thu Aug 01 1991 18:54 | 37 |
| Article 15641
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 08/01/91
Date: 2 Aug 91 01:27:19 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from Anthony Spear, Magellan Project Manager
MAGELLAN STATUS REPORT
August 1, 1991
The Magellan spacecraft and its radar system are performing
nominally. All starcals (star calibrations) and desats (desaturation
of the reaction wheels) yesterday were successful.
The spacecraft star tracker unit (STU) failed a self-test earlier
this morning. However, the attitude control analysts have determined
that this was caused by a star in the STU field of view, and not a
matter of concern.
The spacecraft electrical power bus reached a low of 25.4 volts
during one recent orbit, but has remained above 25.7 volts on all
other orbits. This voltage dip is partly due to increased use of the
battery heaters during solar occultation.
The solar occultations at apoapsis are presently 57 to 58 minutes
long and will peak a few days from now.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 301-355 | "Computers are useless.
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | They can only give you
|_____|/ |_|/ |_____|/ | answers." Pablo Picasso
|
| 456.346 | MAGELLAN Update - August 1 (#2) | MTWAIN::KLAES | All the Universe, or nothing! | Fri Aug 02 1991 11:24 | 42 |
| Article 15656
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update #2 - 08/01/91
Date: 2 Aug 91 07:08:31 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from the JPL Public Information Office
MAGELLAN STATUS REPORT
August 1, 1991
The Magellan spacecraft and its radar system are performing
normally, completing the 2242nd mapping orbit of Venus this morning.
Mapping operations have returned to full-length 165-degree
swaths, from 75 north latitude to the South Pole. Only the southern
12 degrees of each strip covers new territory. However, because it is
being surveyed from the opposite side (the radar looks to the right
instead of the left as before), Magellan scientists anticipate stereo
viewing, as well as the chance to see changes since 8 months ago.
The spacecraft is now in apoapsis solar occultation -- in Venus's
shadow on the outer reach of its orbit -- for about 40 minutes each
orbit. This helps with cooling, as a substitute for the antenna
hiding programmed earlier, but in the absence of sunlight the
spacecraft must rely on its batteries instead of direct solar power
during those periods.
The high-power X-band transmitter had another spurious shutoff on
Friday. Full operation was recovered in minutes, and engineering
communications with Earth were not lost, but it was a nuisance, and
the telecommunications analysts are studying the situation.
#####
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 301-355 | "Computers are useless.
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | They can only give you
|_____|/ |_|/ |_____|/ | answers." Pablo Picasso
|
| 456.347 | MAGELLAN Update - August 2 | MTWAIN::KLAES | All the Universe, or nothing! | Mon Aug 05 1991 21:29 | 35 |
| Article 15684
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 08/02/91
Date: 3 Aug 91 02:28:38 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from Anthony Spear, Magellan Project Manager
MAGELLAN STATUS REPORT
August 2, 1991
Magellan spacecraft performance continues to be excellent. The
spacecraft is operating under the M1207 command sequence, the first
to-week sequence. The present mapping mode is right-look, constant
incidence angle, with full swaths from 75 degrees north latitude to
the South Pole.
For thermal control, the spacecraft performs a flip-flop
maneuver. This mean that it keeps the +Y side of the craft toward the
Sun from the starcal (star calibrations) of one orbit until the next.
Then it turns the -Y side to the Sun for the next orbit.
As of noon (PDT) today, Magellan has completed 2251 mapping
orbits of Venus. With various losses and orbits shortened by thermal
control strategies, we have the equivalent of 1815 full mapping swaths.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 301-355 | "Computers are useless.
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | They can only give you
|_____|/ |_|/ |_____|/ | answers." Pablo Picasso
|
| 456.348 | MAGELLAN Update - August 5 | MTWAIN::KLAES | All the Universe, or nothing! | Tue Aug 06 1991 17:09 | 35 |
| Article 34125
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space
Subject: Magellan Update - 08/05/91
Date: 6 Aug 91 07:04:25 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from Anthony Spear, Magellan Project Manager
MAGELLAN STATUS REPORT
August 5, 1991
The Magellan spacecraft is continuing to perform nominally. All
STARCALs (star calibrations) and DESATs (desaturations) over the
weekend were successful.
The spacecraft is currently operating in a mode which uses a
flip-flop cooling strategy, and a right-look radar approach which maps
the area from about 75 degrees north latitude to the South Pole.
The spacecraft spends more that a 55 minutes of each orbit in the
shadow of Venus (i.e. in apoapsis solar occultation). The occultation
duration will reach its peak of 58 minutes today.
Magellan has now completed 596 orbits, exactly one third, of its
second cycle around Venus.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 301-355 | "Computers are useless.
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | They can only give you
|_____|/ |_|/ |_____|/ | answers." Pablo Picasso
|
| 456.349 | MAGELLAN Update - August 6 | MTWAIN::KLAES | All the Universe, or nothing! | Wed Aug 07 1991 20:35 | 38 |
| Article 15760
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 08/06/91
Date: 7 Aug 91 06:18:34 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from Anthony Spear, Magellan Project Manager
MAGELLAN STATUS REPORT
August 6, 1991
The Magellan spacecraft is performing nominally. Yesterday, the
routine update to the Radar Control Parameter File was sent to the
spacecraft. No commanding is scheduled for today.
The spacecraft continues to operate in a mode which uses a
flip-flop cooling strategy, and a right-look radar to map the area
from about 75 degrees north latitude to the South Pole.
The length of time Magellan spends in the shadow of Venus reached
a maximum of 58 minutes yesterday. The solar occultations will
gradually diminish over the coming weeks, and we expect to resume the
two-hide thermal strategy in early September.
[Round trip light time to Magellan is 5 minutes and 24 seconds.
The spacecraft is currently mapping Venus at about 90 degrees
longitude, which includes the eastern side of Tellus Tessera and the
Ovda Regio in Aphrodite Terra. - Ron Baalke]
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 301-355 | "Computers are useless.
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | They can only give you
|_____|/ |_|/ |_____|/ | answers." Pablo Picasso
|
| 456.350 | MAGELLAN Update - August 7 | MTWAIN::KLAES | All the Universe, or nothing! | Thu Aug 08 1991 20:34 | 66 |
| Article 15786
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 08/07/91
Date: 8 Aug 91 07:05:59 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from Anthony Spear, Magellan Project Manager
MAGELLAN STATUS REPORT
August 7, 1991
The Magellan spacecraft is performing nominally. All starcals
and desats yesterday were successful.
Tomorrow, the spacecraft controllers will uplink the M1221
command sequence which will begin execution on Friday at a few minutes
after noon, Pacific Daylight Time.
The new 2-week sequence will continue to use a flip-flop cooling
strategy, and full mapping swaths from about 75 degrees north latitude
to the South Pole.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 301-355 | "Computers are useless.
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | They can only give you
|_____|/ |_|/ |_____|/ | answers." Pablo Picasso
Article 15787
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update #2 - 08/07/91
Date: 8 Aug 91 04:07:41 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from the JPL Public Information Office
MAGELLAN STATUS REPORT
August 7, 1991
The Magellan spacecraft and its radar system are performing
normally, mapping the area from 75 degrees north to the South Pole,
with the radar looking to the right. Spacecraft star calibrations and
momentum-wheel desaturations are occurring as planned.
The spacecraft is now in apoapsis solar occultation -- in Venus's
shadow on the outer reach of its orbit -- for more than 50 minutes
each orbit, reaching a maximum of 58 minutes Monday. The occultation
period will decline in the coming weeks, and the practice of hiding
behind the big antenna will resume, probably in September. Magellan
is also using another strategy, called flip-flop because the spacecraft
exposes alternate sides to the Sun during its orbits, to keep the
spacecraft cool.
#####
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 301-355 | "Computers are useless.
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | They can only give you
|_____|/ |_|/ |_____|/ | answers." Pablo Picasso
|
| 456.351 | MAGELLAN Update - August 8 | MTWAIN::KLAES | All the Universe, or nothing! | Fri Aug 09 1991 14:59 | 37 |
| Article 15822
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 08/08/91
Date: 9 Aug 91 06:45:42 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from Anthony Spear, Magellan Project Manager
MAGELLAN STATUS REPORT
August 8, 1991
The Magellan spacecraft and its radar system are performing
nominally. Today, the spacecraft controllers will uplink the M1221
command sequence which will begin execution on tomorrow at about noon,
Pacific Daylight Time (PDT).
Correcting our report from yesterday, the 2-week sequence will
NOT use a flip-flop nor the two-hide cooling strategy, but will
perform nominal, full-swath radar mapping. This is the first time
since early April that Magellan has been able to operate in the
nominal mode.
So far in Cycle 2, Magellan has completed 620 orbits and has
mapped about 17% of the Venus surface; 11.7% represents right-look
mapping of areas imaged during Cycle 1, and 5.3% is new area coverage
at the South Pole and the part missed during Cycle 1 during Superior
Conjunction.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 301-355 | "Computers are useless.
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | They can only give you
|_____|/ |_|/ |_____|/ | answers." Pablo Picasso
|
| 456.352 | MAGELLAN Update - August 9 | MTWAIN::KLAES | All the Universe, or nothing! | Sun Aug 11 1991 18:15 | 38 |
| Article 15859
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 08/09/91
Date: 10 Aug 91 02:38:30 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from Anthony Spear, Magellan Project Manager
MAGELLAN STATUS REPORT
August 9, 1991
Magellan spacecraft performance continues to be excellent. It has now
achieved a record of 82 consecutive successful starcals (star calibrations).
The spacecraft begins operating under the M1221 command sequence about
noon (PDT) today. This sequence represents the first normal radar mapping
since early April. Since then mapping has been altered by thermal maneuvers
to cool the spacecraft.
As of 9:45 AM PDT tomorrow, Magellan completed its first year at Venus.
The spacecraft has completed 2688 orbits and has performed radar mapping of
the surface on 2294 orbits. The area imaged represents 89% of the total
planet.
Since the beginning of Cycle 2 on May 16, 1991, Magellan has completed
633 orbits. Due to the adverse thermal environment most of the radar swaths
have been shortened by the need to cool the spacecraft in the shade of the
High Gain Antenna.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 301-355 | "Computers are useless.
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | They can only give you
|_____|/ |_|/ |_____|/ | answers." Pablo Picasso
|
| 456.353 | MAGELLAN Update - August 12 | MTWAIN::KLAES | All the Universe, or nothing! | Mon Aug 12 1991 19:38 | 35 |
| Article 15908
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 08/12/91
Date: 12 Aug 91 23:29:40 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from Anthony Spear, Magellan Project Manager
MAGELLAN STATUS REPORT
August 12, 1991
The Magellan spacecraft is continuing to perform nominally. All
STARCALs (star calibrations) and DESATs (desaturations) over the
weekend were successful. Magellan has had 105 consecutive successful
STARCALs; only 3 missed stars in the past 30 days.
On Friday, the spacecraft fault protection commanded a swap of
the IODA (Input/Output Device Assembly) soon after the start of the
M1221 command sequence. It was quickly determined that the new
sequence had an error in the assumed spacecraft orientation as it
ended the flip-flop cooling strategy. Corrective commands were
uplinked on Friday afternoon and the spacecraft has continued normal
operations through the weekend.
Magellan has now completed 2324 mapping orbits of Venus.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 301-355 | "Computers are useless.
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | They can only give you
|_____|/ |_|/ |_____|/ | answers." Pablo Picasso
|
| 456.354 | MAGELLAN Update - August 13 | MTWAIN::KLAES | All the Universe, or nothing! | Wed Aug 14 1991 19:50 | 29 |
| Article 15954
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 08/13/91
Date: 14 Aug 91 04:02:51 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from Anthony Spear, Magellan Project Manager
MAGELLAN STATUS REPORT
August 13, 1991
The Magellan spacecraft is performing nominally. Yesterday, the routine
update to the Radar Control Parameter File was sent to the spacecraft.
The spacecraft experienced another spurious shutoff (SSO) of the high
power transmitter (TWTA) yesterday morning. As in the previous SSO's, the
spacecraft automatically corrected the problem within a few minutes. A
non-standard command for a memory read-out to analyze the event was uplinked
this morning.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 301-355 | Good judgement comes from
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | experience. Experience
|_____|/ |_|/ |_____|/ | comes from bad judgement.
|
| 456.355 | MAGELLAN Update - August 14 | MTWAIN::KLAES | All the Universe, or nothing! | Wed Aug 14 1991 20:31 | 36 |
| Article 15983
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 08/14/91
Date: 14 Aug 91 23:49:50 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from Anthony Spear, Magellan Project Manager
MAGELLAN STATUS REPORT
August 14, 1991
The Magellan spacecraft is performing nominally. All starcals (star
calibrations) and desats (desaturations) yesterday were successful.
The memory read-out yesterday confirmed that the TWTA (high power
transmitter) spurious shutoff on Monday occurred at 10:23 AM PDT and was the
cause of the data outage at that time.
Tomorrow, commands will be sent up to offpoint the solar panels by -45
degrees during the non-mapping portion of each orbit.
Magellan continues to collect full mapping swaths in a right-look,
constant incidence angle mode, covering the area from 75 degrees north
latitude to the South Pole. The major areas presently being mapped include
the eastern portion of Ishtar Terra, Tellus Regio, and west-central Aphrodite
Terra.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 301-355 | Good judgement comes from
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | experience. Experience
|_____|/ |_|/ |_____|/ | comes from bad judgement.
|
| 456.356 | MAGELLAN Update - August 15 | MTWAIN::KLAES | All the Universe, or nothing! | Fri Aug 16 1991 18:35 | 41 |
| Article 16018
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 08/15/91
Date: 16 Aug 91 00:16:18 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from the JPL Public Information Office
MAGELLAN STATUS REPORT
August 15, 1991
The Magellan spacecraft and its radar system are performing
normally. All star calibrations and momentum wheel desaturations have
been successful.
Commands were sent today to offpoint the solar panels by 45
degrees during the non-mapping portion of each orbit for thermal
protection.
Magellan continues to collect mapping swaths in a right-looking
mode, covering the area from 75 degrees north latitude to the south
pole. The major areas presently being mapped include the eastern
portion of Ishtar Terra, Tellus Regio, and west- central Aphrodite
Terra.
The first CD-ROM discs of images were released and distributed in
March of this year. Full CD-ROM production started this month and the
project is planning to release 8 CD-ROMs per month hereafter. All of
the cycle one photoproducts will be released prior to October and
complete distribution of both first cycle photoproducts and CD-ROMs
will be completed by February 1992.
_____
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 301-355 | Good judgement comes from
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | experience. Experience
|_____|/ |_|/ |_____|/ | comes from bad judgement.
|
| 456.357 | MAGELLAN Update - August 19 | MTWAIN::KLAES | All the Universe, or nothing! | Tue Aug 20 1991 16:34 | 40 |
| Article 16090
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 08/19/91
Date: 20 Aug 91 04:37:04 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from Anthony Spear, Magellan Project Manager
MAGELLAN STATUS REPORT
August 19, 1991
Magellan spacecraft performance continues to be excellent.
Temperatures on the Propulsion Equipment Plant and two of the Rocket
Engine Modules continue to increase as the spacecraft approaches
Inferior Conjunction this week. These temperatures are expected to
level off, then peak, the start down after Inferior Conjunction.
The spacecraft continues its series of over 150 successful star
calibrations. This is attributed to the fact that the starcal
maneuver is presently being performed in the shadow of Venus. This
eliminates the possibility of sun-lit particles confusing the star
tracker unit.
Today, another radar control parameter file will be uplinked to
the spacecraft.
As of noon (PDT) today, Magellan has completed 2754 orbits and
has performed radar mapping of the surface on 2376 orbits. The area
imaged represents 89% of the total planet, with about 11% covered in
both cycles 1 and 2.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 301-355 | Good judgement comes from
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | experience. Experience
|_____|/ |_|/ |_____|/ | comes from bad judgement.
|
| 456.358 | Problem with Magellan loosing track of earth found | DECWIN::FISHER | Klingons don't "enter a relationship"...they conquer | Tue Aug 20 1991 16:44 | 26 |
| I read an article (in the Globe yesterday) which said that they had found the
problem which caused loss of contact several times in the past year. It was
apparently an error in the realtime software.
This is a translation/interpretation into computerese from newspaperese via my
memory, so there is a lot of speculation included, but:
It seems that when Mag. is doing a context switch from foreground to background
it is supposed to "send two code words". It seems that there is a small window
between the sending of these two hunks of info being sent when something
(another interrupt?) can happen. If the it happens at that time, M. is left
with a "time bomb" which causes it to die later.
Sounds like maybe someone did not disable interrupts when a return address
was being pushed on a stack somewhere???
Also the article said that the problem was traced to a "program that writes
software". A compiler??
Anyway, it went on to claim that the problem had been fixed, tested, and
uploaded.
Oh yes, they said that they were able to find it because the problem happened on
a ground test article. Nothing like a reproducible problem, eh?
Burns
|
| 456.359 | | EMDS::SILVERSTEIN | Bob Silverstein | Tue Aug 20 1991 20:26 | 18 |
|
Yes, it was software. I had also heard this from the JPL person I meet
on my eclipse cruise trip in July.
I had entered some other info about Galileo we talked about, but forgot
to mention about the Magellan problem and fix. Although we did not get
into the detail level mentioned in the previous note.
There was so much we talked about in so short a time. If my memory gets
jogged about something else, I'll let you know.
Bob
|
| 456.360 | MAGELLAN Updates - August 20-21 | MTWAIN::KLAES | All the Universe, or nothing! | Wed Aug 21 1991 19:49 | 120 |
| Article 16106
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 08/20/91
Date: 21 Aug 91 05:36:22 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from Anthony Spear, Magellan Project Manager
MAGELLAN STATUS REPORT
August 20, 1991
Magellan spacecraft performance continues to be excellent.
Temperatures on the Propulsion Equipment Plant and two of the
Rocket Engine Modules continue to increase as the spacecraft
approaches Inferior Conjunction this week. These temperatures are
expected to level off, then peak, the start down after Inferior
Conjunction.
The spacecraft continues its series of over 156 successful star
calibrations. This is attributed to the fact that the starcal
maneuver is presently being performed in the shadow of Venus. This
eliminates the possibility of sun-lit particles confusing the star
tracker unit.
As of noon (PDT) today, Magellan has completed 2760 orbits and
has performed radar mapping of the surface on 2382 orbits.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 301-355 | Good judgement comes from
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | experience. Experience
|_____|/ |_|/ |_____|/ | comes from bad judgement.
Article 16111
From: pgf@space.mit.edu (Peter G. Ford)
Newsgroups: sci.space,sci.astro
Subject: Re: Magellan Update - 08/20/91
Date: 21 Aug 91 03:37:01 GMT
Sender: news@athena.mit.edu (News system)
Organization: MIT Center for Space Research
In article <1991Aug20.193234.27387@jarvis.csri.toronto.edu>
wayne@csri.toronto.edu (Wayne Hayes) writes:
>baalke@kelvin.jpl.nasa.gov (Ron Baalke) writes:
>> Temperatures on the Propulsion Equipment Plant and two of the Rocket
>>Engine Modules continue to increase as the spacecraft approaches Inferior
>>Conjunction this week. These temperatures are expected to level off, then
>>peak, the start down after Inferior Conjunction.
>
>Err, why would a conjunction change the spacecraft's temperature? Is the
>reflection from the Earth really *that* bright? :-)
>
>Is it because part of the spacecraft always has to point at the Earth
>(like the antenna) and the other side is getting warm? But then again
>it's always spinning and Magellen doesn't have a dual spin mode as far
>as I can remember...
>
>I'm confused.
Magellan doesn't spin - it is stabilized by reaction wheels. During
each 3.26 hour orbital period, it spends about 2.5 hours with its
high-gain antenna pointing to Earth so that it can transmit the radar
data that it records during the 37 minutes when its antenna tracks the
Venus surface. At inferior conjunction, the Sun, Magellan, and Earth
are (approximately) aligned, so the Sun shines directly on the
"bottom" of the spacecraft for most of the orbit period, causing some
components to overheat. It has become necessary to reduce the playback
time (thereby throwing away some data) and point the antenna at the
Sun to allow the rest of the spacecraft in its shadow to cool down.
Peter Ford
MIT and Magellan Project
Article 16121
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 08/21/91
Date: 22 Aug 91 02:02:19 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from:
PUBLIC INFORMATION OFFICE
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIF. 91109. TELEPHONE (818) 354-5011
MAGELLAN STATUS REPORT
August 21, 1991
Magellan spacecraft performance continues to be excellent.
Temperatures on the propulsion equipment plate over the hydrazine
valves hit more than 80 degrees C (176 F) today. The stop-mapping
point is currently 85 C (185 F). A command to point the high-gain
antenna toward the sun instead of Venus was prepared as a contingency,
but project officials do not expect it will be necessary to stop mapping.
The spacecraft continues its series of more than 163 successful
star calibrations. This is attributed to the fact that the star-cal
maneuver is presently being performed in the shadow of Venus, thus
eliminating the possibility of sun-lighted particles confusing the
star tracker unit.
#####
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 301-355 | Good judgement comes from
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | experience. Experience
|_____|/ |_|/ |_____|/ | comes from bad judgement.
|
| 456.361 | MAGELLAN Update - August 21 (#2) | MTWAIN::KLAES | All the Universe, or nothing! | Thu Aug 22 1991 17:16 | 36 |
| Article 16124
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update #2 - 08/21/91
Date: 22 Aug 91 03:45:27 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from Anthony Spear, Magellan Project Manager
MAGELLAN STATUS REPORT
August 21, 1991
Magellan spacecraft performance continues to be excellent.
Temperatures on the propulsion equipment plate over the hydrazine
valves hit more than 80 degrees C today. The stop-mapping point is
currently 85 C. A mapping quaternion to point the High Gain Antenna
at the Sun instead of Venus was prepared as a contingency maneuver.
The spacecraft continues its series of over 163 successful star
calibrations.
As of noon (PDT) today, Magellan has completed 2767 orbits and
has performed radar mapping of the surface on 2391 orbits.
[Round trip light time to Magellan is 4 minutes, 47 seconds. The
spacecraft is currently mapping Venus at about 111 degrees longitude.
- Ron Baalke].
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 301-355 | Good judgement comes from
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | experience. Experience
|_____|/ |_|/ |_____|/ | comes from bad judgement.
|
| 456.362 | MAGELLAN Update - August 22 | MTWAIN::KLAES | All the Universe, or nothing! | Thu Aug 22 1991 20:17 | 33 |
| Article 16146
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 08/22/91
Date: 23 Aug 91 02:06:21 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from Anthony Spear, Magellan Project Manager
MAGELLAN STATUS REPORT
August 22, 1991
Magellan spacecraft performance continues to be excellent.
Temperatures on the Propulsion Equipment Plate went to a maximum of
81.2 degrees C and leveled off. The stop mapping limit is currently
85 degrees C. A mapping quaternion to point the High Gain Antenna at the
Sun instead of Venus was prepared as a contingency maneuver.
The spacecraft continues its series of over 171 successful star
calibrations.
As of noon (PDT) today, Magellan has completed 2774 orbits and has
performed radar mapping of the surface on 2398 orbits.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 301-355 | Good judgement comes from
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | experience. Experience
|_____|/ |_|/ |_____|/ | comes from bad judgement.
|
| 456.363 | MAGELLAN software bugs | MTWAIN::KLAES | All the Universe, or nothing! | Fri Aug 23 1991 14:41 | 38 |
| Article 34735
From: jfc@athena.mit.edu (John F Carr)
Newsgroups: sci.space
Subject: Magellan software problems
Date: 23 Aug 91 02:16:31 GMT
Sender: news@athena.mit.edu (News system)
Organization: Massachusetts Institute of Technology
The Boston Globe printed a story monday attributed to the Washington Post.
Interesting paragraphs of the article:
NASA engineers have found and fixed a computer software error
that had caused the spacecraft Magellan to lose contact with
Earth repeatedly after its arrival at the planet Venus about
a year ago, according to sources.
[...]
The error resulted from a defect in a program used to write
software for Magellan and other spacecraft. The discovery
should prevent the same bug from being written into the
software of other space missions.
[...]
The error made the computer that controls the spacecraft's
position vulnerable for a fraction of a second when it was
switching from background tasks, such as planning the craft's
next move, to critical tasks that were to be done at once, such
as turning the craft, according to a source familiar with the
problem who asked for anonymity.
The first sentence in the second quoted paragraph surprised me -- I thought
spacecraft code (esp. parts like task switching) was written in a low level
language, not generated by a program.
--
John Carr (jfc@athena.mit.edu)
|
| 456.364 | | DECWIN::FISHER | Klingons don't "enter a relationship"...they conquer | Fri Aug 23 1991 15:31 | 4 |
| I think they use languages like Jovial. Maybe they will switch to Ada at
some point. (I think this has been discussed in more detail elsewhere)
Burns
|
| 456.365 | MAGELLAN Update - August 26 | MTWAIN::KLAES | All the Universe, or nothing! | Tue Aug 27 1991 13:07 | 43 |
| Date: 27 Aug 91 01:14:09 GMT
From: (Ron Baalke)
Subject: Magellan Update - 08/26/91
Forwarded from Anthony Spear, Magellan Project Manager
MAGELLAN STATUS REPORT
August 26, 1991
The Magellan spacecraft is performing nominally, although the
spacecraft controllers had some excitement over the weekend.
Last Friday, the head temperature on the on-board tape recorder
DMS-B (Data Management Subsystem B) exceeded the alarm limit of 43
degrees C. The "stop mapping" limit is 45 degrees C. Some temporary
thermal relief was obtained Friday night by commanding the offpointing
of the solar panels during the mapping part of each orbit starting on
Orbit 2898. Also, early Saturday morning the DMS-A tape, which had
been "on" but not in use, was turned off to reduce the heat input to
the spacecraft bus. These actions remain in effect.
Commands were prepared to switch to a 15 minute early turn from
mapping. When the tape head temperature reached 44.1 degrees C, the
15-minute early turn strategy was enabled on Orbit #2913 shortly
before midnight PDT last night.
The tape head temperatures have now dropped to 42.7 degrees C and
have stayed under the alarm limit on subsequent orbits. Preparations
are also being made re-enabling the two-hide thermal control strategy.
Along with the temperature concerns, the spacecraft team had to
handle a bad attitude update on Saturday afternoon. A set of commands
to disable the gyro biases and raise the attitude update limit were
uplinked to Magellan, and the precise pointing of the High Gain
Antenna was reestablished within one orbit. No radar data was lost.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 301-355 | Good judgement comes from
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | experience. Experience
|_____|/ |_|/ |_____|/ | comes from bad judgement.
|
| 456.366 | MAGELLAN Update - August 27 | MTWAIN::KLAES | All the Universe, or nothing! | Wed Aug 28 1991 14:45 | 85 |
| Date: 28 Aug 91 04:05:10 GMT
From: (Ron Baalke)
Subject: Magellan Update - 08/27/91
Forwarded from Anthony Spear, Magellan Project Manager
MAGELLAN STATUS REPORT
August 27, 1991
The Magellan spacecraft is performing nominally. It is presently
operating in a flip-flop mapping mode for thermal control which turns
the +Y or -Y side of the craft toward the sun on alternate orbits.
Since shortly before midnight Sunday, the spacecraft has also
used a 15-minute early turn from mapping. This has resulted in
mapping swaths which extend from 75 degrees north latitude to about 50
degrees south (where the full swaths would extend to the South Pole).
The tape head temperatures dropped to 42.7 degrees C and 42
degrees C on alternate orbits, but climbed back to 43.4 degrees C on
Orbit 2921 early today. The alarm limit is 44 degrees C.
Yesterday, controllers uplinked a command to change the solar
array drive mechanism's commanded position and an update to the radar
control parameter file.
Command sequence M1241 is being prepared for uplink tomorrow and
will re-enable the two-hide thermal control strategy. It will include
two 20-minute hides and will shift the area being mapped to start
about 5 degrees south latitude and extend to the South Pole.
The two-hide thermal control strategy, with increasing hide
times, will be required through the rest of Cycle 2 which ends on
January 15, 1992.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 301-355 | Good judgement comes from
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | experience. Experience
|_____|/ |_|/ |_____|/ | comes from bad judgement.
Date: 28 Aug 91 02:42:10 GMT
From: (Ron Baalke)
Subject: Magellan Update #2 - 08/27/91
Forwarded from:
PUBLIC INFORMATION OFFICE
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIF. 91109. TELEPHONE (818) 354-5011
MAGELLAN STATUS REPORT
August 27, 1991
Magellan spacecraft performance continues to be excellent, but
thermal safety measures had to be taken during the weekend to protect
the tape recorder.
Late Friday, the head temperature of the recorder exceeded the
alarm limit of 43 degrees C (109.4 F). The "stop mapping" limit is 45
C (113 F). Some temporary thermal relief was obtained Friday night by
commanding the solar panels to point away from the spacecraft during
the mapping part of each orbit. Also, the second tape recorder, which
was "on" but not in use, was turned off to reduce heat in the
spacecraft bus.
Late Sunday, commands were sent to reduce mapping by 15 minutes
in each orbit so the spacecraft could be put in the shade of its
high-gain antenna. The tape head temperatures have dropped slightly
and have stayed under the alarm limit. The safety measures remain in
effect today.
New commands will be sent to the spacecraft Thursday to re-
establish the "two-hide" strategy used earlier. It will put the
spacecraft in the shade of its antenna twice in each orbit.
_____
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 301-355 | Good judgement comes from
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | experience. Experience
|_____|/ |_|/ |_____|/ | comes from bad judgement.
|
| 456.367 | Hides? (That last abbreviation should be V/S/E, not O) | DECWIN::FISHER | Klingons don't "enter a relationship"...they conquer | Thu Aug 29 1991 15:36 | 8 |
| Does anyone know if these hides were intended all along to be SOP for so much
of the time? I was under the impression that they were "contingency" plans,
or at least would only be needed for a very small part of the Venus/Sun/Earth
geometry. It seems like they are now in use for a large portion of the time.
(I don't know what percentage of possible V/S/O geometries have been encountered
yet, though).
Burns
|
| 456.368 | MAGELLAN Update - August 29 | MTWAIN::KLAES | All the Universe, or nothing! | Thu Aug 29 1991 20:27 | 41 |
| Article 16385
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 08/29/91
Date: 30 Aug 91 03:20:15 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from Anthony Spear, Magellan Project Manager
MAGELLAN STATUS REPORT
August 29, 1991
The Magellan spacecraft is performing nominally. All starcals
(star calibrations) and desats (desaturations of the reaction wheels)
yesterday were successful.
Command sequence M1241, which began execution early today,
includes two 20-minute hide periods and maps the area from about 5
degrees north of the equator to the South Pole.
Critical spacecraft components have cooled about two or three
degrees since the start of the two-hide sequence. The solar panel
offpoint was changed to +45 degrees from the sun line.
Spacecraft controllers have prepared some contingency commands to
cool the spacecraft in the event the present strategy does not
continue to maintain acceptable temperatures. These include an MQPC
file which would roll the spacecraft during mapping, such as was done
during the last several days, and a +Z to sun maneuver.
Magellan has now completed 2449 mapping orbits, 773 since the
start of Cycle 2. So we're 43% finished with Cycle 2.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 301-355 Telos | Good judgement comes from
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | experience. Experience
|_____|/ |_|/ |_____|/ | comes from bad judgement.
|
| 456.369 | MAGELLAN Update - August 28 | MTWAIN::KLAES | All the Universe, or nothing! | Thu Aug 29 1991 21:11 | 42 |
| Article 16387
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 08/28/91
Date: 29 Aug 91 02:20:45 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from Anthony Spear, Magellan Project Manager
MAGELLAN STATUS REPORT
August 28, 1991
The Magellan spacecraft is performing nominally. All starcals (star
calibrations) and desats (desaturations) yesterday were successful.
Last night, spacecraft controllers uplinked a change to the MQPC
file which resulted in the spacecraft performing a 180 degree roll
during its mapping pass. This helped to cool the tape recorder heads
by about 6 degrees C. However, the Propulsion Equipment Plate
exceeded the alarm limit, reaching 85.4 degrees C (with a "stop
mapping" limit of 90 degrees C) but is not expected to pose any
problems before the start of the new sequence tommorrow morning.
The spacecraft engineers had anticipated these thermal control
challenges during Cycle 2 due to the unfavorable geometry of the sun
and orbit plane. The two-hide thermal control strategy, with
increasing hide times, will be required through the rest of Cycle 2
which ends on January 15, 1992.
Command sequence M1241, which will be uplinked late today and
begins execution early tomorrow, will include two 20-minute hides
periods and will shift the area being mapped to start about 5 degrees
north of the equator and extend to the South Pole.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 301-355 Telos | Good judgement comes from
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | experience. Experience
|_____|/ |_|/ |_____|/ | comes from bad judgement.
|
| 456.370 | MAGELLAN Update - August 29 | MTWAIN::KLAES | All the Universe, or nothing! | Fri Aug 30 1991 12:57 | 37 |
| Date: 30 Aug 91 03:20:15 GMT
From: (Ron Baalke)
Subject: Magellan Update - 08/29/91
Forwarded from Anthony Spear, Magellan Project Manager
MAGELLAN STATUS REPORT
August 29, 1991
The Magellan spacecraft is performing nominally. All starcals
(star calibrations) and desats (desaturations of the reaction wheels)
yesterday were successful.
Command sequence M1241, which began execution early today,
includes two 20-minute hide periods and maps the area from about 5
degrees north of the equator to the South Pole.
Critical spacecraft components have cooled about two or three
degrees since the start of the two-hide sequence. The solar panel
offpoint was changed to +45 degrees from the sun line.
Spacecraft controllers have prepared some contingency commands
to cool the spacecraft in the event the present strategy does not
continue to maintain acceptable temperatures. These include an MQPC
file which would roll the spacecraft during mapping, such as was done
during the last several days, and a +Z to sun maneuver.
Magellan has now completed 2449 mapping orbits, 773 since the
start of Cycle 2. So we're 43% finished with Cycle 2.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 301-355 Telos | Good judgement comes from
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | experience. Experience
|_____|/ |_|/ |_____|/ | comes from bad judgement.
|
| 456.371 | Channel found on Venus 4,200 miles long | MTWAIN::KLAES | All the Universe, or nothing! | Fri Aug 30 1991 12:58 | 89 |
| Date: 30 Aug 91 11:50:31 GMT
From: (Ron Baalke)
Subject: Magellan Discovers the Longest Channel in the Solar System
Paula Cleggett-Haleim
Headquarters, Washington, D.C. August 30, 1991
(Phone: 202/453-1547)
Jim Doyle
Jet Propulsion Laboratory, Pasadena, Calif.
(Phone: 818/354-5011)
RELEASE: 91-141
MAGELLAN DISCOVERS LONGEST CHANNEL IN SOLAR SYSTEM
The Magellan spacecraft, mapping the surface of Venus with
imaging radar, has discovered the longest channel known in the solar
system, a project spokesman said at NASA's Jet Propulsion Laboratory,
Pasadena, Calif..
The channel crosses the plains of Venus for 4,200 miles,
longer than the Nile River, the longest river on Earth, said Project
Scientist Dr. Steve Saunders. "The very existence of such a long
channel is a great puzzle," Saunders said. "If the long channel were
carved by something flowing on the surface, the liquid must have had
unusual properties," he added.
Saunders said it may have been some material that was near its
freezing or melting point at the average surface conditions of Venus
-- surface pressure 90 times that of Earth and a temperature of 864
degrees Fahrenheit.
"There are no very likely candidates for a liquid," Saunders
said. "Lava, even very high temperature types, would need to have a
very high extrusion rate to flow so far. This is not consistent with
the uniform narrow channel morphology."
He said the channel is very uniform in width, averaging little
more than 1 mile across. "It follows a sinuous, smoothly-curving course
that can be traced continuously on the surface just west of Atla Regio
northward nearly to the large basin called Atalanta Planitia."
A few segments of the channel were mapped in 1984 by the
Soviet Venera 15 and 16 orbiters which carried radar capable of
resolving features down to 0.6 to 1.2 miles. With the higher
resolution of Magellan, about 400 feet, the channel can be traced
unbroken along its course, Saunders said.
Similar channels have been seen on the surfaces of many of the
plains in other parts of Venus, he said. In some cases the channels
terminate in lava flows, indicating that they probably were carved out
by molten lava from a volcanic eruption. No similar features are now
known on Earth, although lava channels are known to have formed on
Earth billions of years ago.
"The challenge of understanding the origin of this channel
will lead to better understanding of planetary geological processes
and many related fields such as material properties and fluid
mechanics," Saunders said.
Magellan is currently mapping the south pole of Venus. In the
first 243-day mapping cycle which ended May 15, the spacecraft mapped
84 percent of the planet. In its second cycle, its has mapped for the
second time a 600-mile wide strip and that section of Venus is being
examined to see if any changes occurred from one cycle to the other.
Preliminary analysis of that data has so far revealed no changes
occurring on the surface of Venus between mapping cycles.
Magellan now has its high-gain antenna turned to the right as
it maps long strips of the surface. During the first mapping cycle,
the side-looking radar was turned to the left. The antenna was turned
to the right to map the south pole.
Many of the same features that were imaged from the left
during the first cycle are being imaged now from the new angle, which
will permit investigators to get more accurate measurements and also
will provide three-dimensional views of some features.
The Jet Propulsion Laboratory manages the Magellan project for
NASA's Office of Space Science and Applications, Washington, D.C.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 301-355 Telos | Good judgement comes from
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | experience. Experience
|_____|/ |_|/ |_____|/ | comes from bad judgement.
|
| 456.372 | Landslide found on Venus | MTWAIN::KLAES | All the Universe, or nothing! | Tue Sep 03 1991 22:22 | 104 |
| Article 1631
From: clarinews@clarinet.com (WILLIAM HARWOOD, UPI Science Writer)
Newsgroups: clari.tw.space
Subject: Surface change seen on Venus
Date: 30 Aug 91 20:33:57 GMT
NASA's Magellan probe has discovered a giant landslide on
Venus that apparently was triggered by a ``venusquake'' measuring 5 on
the Richter scale, a major discovery showing the hellish planet may be
geologically active, scientists announced Friday.
Project scientist Stephen Saunders at NASA's Jet Propulsion
Laboratory in Pasadena, Calif., said radar images taken by Magellan
July 23 clearly show a landslide measuring 1.8 miles wide and 4.7
miles long that was not present when the spacecraft sailed over the
same area in November.
The discovery, made Thursday night based on before-and-after
images of the area, marks the first direct evidence of a change on the
surface of Venus since Magellan began mapping the planet in 1989.
``The best explanation that we've come up with is we're seeing
a giant landslide,'' Saunders said. ``We think what's happened is a
large amount of material ... has slumped and flowed out across this
area. It's very exciting.''
He said the most likely cause of the landslide was ``an
earthquake, or a venusquake, if you will. That's a likely thing.''
``It's something like the equivalent of a magnitude 5
earthquake (on the Richter scale),'' Saunders said. ``It may be that
Venus is still alive.''
Wesley Huntress, director of NASA's solar system exploration
division in Washington, called the landslide a ``major discovery.''
``What we have are before-and-after images which show distinct
evidence of significant change that must have occurred between the times
we took these images,'' he said. ``It shows that Venus is geologically
alive in the same sense that the Earth is geologically alive.''
While the new images are the first to show a change on the
planet's surface, Saunders said he remains confident Venus is
volcanically active. Lava from planet-wide volcanism apparently
resurfaces vast areas of Venus every 500 million years or so. But so
far, no direct evidence has been found.
The Magellan probe, launched from the shuttle Atlantis on May
4, 1989, slipped into orbit around Venus on Aug. 19, 1990. The solar-
powered spacecraft uses radar beams instead of visible light to
``see'' through the thick clouds that perpetually block the planet's
surface from view.
The resulting data can be processed by computers on Earth to
create photograph-like images of Venus's surface, showing features as
small as 350 feet across -- about the size of a football field -- and
10 times better than the best previous data. The data also can be used
to make dramatic movies.
The landslide was discovered Thursday night by a Magellan
project scientist studying two views of Aphrodite Terra, an area of
equatorial highlands marked by steep mountains and heavily fractured
terrain.
When Magellan flew over the area last November, no such
landslide was visible. But when the spacecraft sailed over July 23, it
recorded a massive shift of surface material -- some 3,924 cubic
yards. It was the first direct evidence that Venus is still undergoing
geological change.
Despite recently resolved computer problems that have
occasionally knocked the craft out of contact with Earth, Magellan
completed its initial survey of Venus on May 15, mapping 84 percent of
the planet's surface.
Since then, the probe has been filling in gaps in the initial
survey and mapping more of the southern hemisphere, repeating previous
observations and allowing scientists to look for changes.
NASA scientists reported Thursday that Magellan had discovered
the longest known channel in the solar system, a geological scar
longer than the Nile River.
JPL researchers said they do not know what formed the channel,
which measures about 1 mile across and runs for about 4,200 miles in a
winding, smoothly curved course across the plains of Venus.
Numerous smaller channels have been detected by Magellan, some
of which apparently were carved out by lava from volcanic eruptions.
But it is unlikely that lava, even at very high temperatures, would have
the very high rate of flow needed to form the newly discovered channel.
In many ways, Venus is Earth's twin in the solar system. Both
planets are similar in size and mass; both are relatively close to the
sun, and both probably were almost identical very early in the history
of the solar system.
But somewhere along the way, the environments of Venus and
Earth diverged, leaving Venus the victim of a runaway greenhouse
effect in which the solar radiation trapped by the planet's thick
cloud cover produces surface temperatures of 900 degrees Fahrenheit --
hot enough to melt lead -- and pressures comparable to those found at
an ocean depth of 2,500 to 3,000 feet.
|
| 456.373 | Update - September 3 | MTWAIN::KLAES | All the Universe, or nothing! | Tue Sep 03 1991 22:23 | 39 |
| Article 16524
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 09/03/91
Date: 4 Sep 91 02:59:06 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from Anthony Spear, Magellan Project Manager
MAGELLAN STATUS REPORT
September 3, 1991
The Magellan spacecraft is performing nominally. On Friday, the
spacecraft missed two stars and took a bad attitude update. The bias
gains and update limit were changed temporarily to allow the next
starcals (star calibrations) to adjust the pointing accuracy. Since
that time, only one missed star has been noted. An attitude reference
loss alarm was recorded over the weekend, but this was believed to be
caused by the albedo of Venus.
The spacecraft is presently using two 20-minute hide periods,
offpointing of the solar panels, and the roll MQPC to control the
temperatures, but the temperatures are beginning to rise again. The
transmitter and Electronic Power Converter/Traveling Wave Tube
Amplifier are increasing by one degree per day.
One option available to spacecraft controllers is to switch from
the present roll MQPC to the standard mapping MQPC file, which will
cool the radio components while raising the tape recorder and CDS
(Command Data Subsystem) temperatures slightly.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 301-355 Telos | Good judgement comes from
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | experience. Experience
|_____|/ |_|/ |_____|/ | comes from bad judgement.
|
| 456.374 | Updates - September 4-6 | MTWAIN::KLAES | All the Universe, or nothing! | Mon Sep 09 1991 19:38 | 147 |
| Date: 5 Sep 91 02:16:50 GMT
From: elroy.jpl.nasa.gov!kelvin.jpl.nasa.gov!baalke@decwrl.dec.com (Ron Baalke)
Subject: Magellan Update - 09/04/91
Forwarded from Anthony Spear, Magellan Project Manager
MAGELLAN STATUS REPORT
September 4, 1991
The Magellan spacecraft is performing nominally. All starcals
(star calibrations) and desats (desaturations) yesterday were successful.
Yesterday spacecraft controllers uplinked a change to the MQPC
file which removed the 180 degree roll during each mapping pass. This
helped to cool the transmitter and EPC (Electronic Power Converter) by
as much as 16 degrees C. However, it caused the tape recorder head
temperature to rise 4 degrees, and Bay 7 (which contains the CDS
(Command Data Subsystem)) now peaks at 50 degrees C (with a red alarm
limit of 55 degrees C).
The spacecraft engineers had anticipated these thermal control
challenges during Cycle 2 due to the unfavorable geometry of the sun
and orbit plane. The two-hide thermal control strategy, with
increasing hide times, will be required through the rest of Cycle 2
which ends on January 15, 1992.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 301-355 Telos | Good judgement comes from
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | experience. Experience
|_____|/ |_|/ |_____|/ | comes from bad judgement.
Date: 5 Sep 91 21:29:38 GMT
From: (Ron Baalke)
Subject: Re: Magellan Landslide Images
Here is the photo caption that goes along with the Magellan landslide image.
----------------------------------------------------------------------
PUBLIC INFORMATION OFFICE
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIFORNIA 91109. TELEPHONE (818) 354-5011
PHOTO CAPTION Magellan
P-38975 MGN69
August 30, 1991
Landslides on Venus! The image of the left was taken in late November
of 1990 during Magellan's first trip around Venus. The image on the
right was taken July 23, as the Magellan spacecraft passed over the
region for the second time. Each image is 24 kilometers (14.4 miles)
across and 38 kilometers (23 miles) long, and is centered at 2 degrees
south latitude and 74 degrees east longitude. This pair of Magellan
images shows a region in Aphrodite Terra, within a steeply sloping
valley that is cut by many fractures. In the center of the image on
the right, a bright, flow-like area can be seen extending to the west
(left) of a bright fracture. The bright, rough area has appeared and
the fracture has changed position in the 8 months since the first
image was made. A "Venusquake" may have occurred, producing a new
scarp and causing a landslide (the bright area) to form. This is the
first evidence of active tectonics occurring on other planets in the
solar system. Resolution of the Magellan data is 120 meters (400 feet).
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 301-355 Telos | Good judgement comes from
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | experience. Experience
|_____|/ |_|/ |_____|/ | comes from bad judgement.
Date: 6 Sep 91 01:41:59 GMT
From: (Ron Baalke)
Subject: Magellan Update - 09/05/91
MAGELLAN STATUS REPORT
September 5, 1991
The Magellan spacecraft is performing nominally. All starcals (star
calibrations) and desats (desaturations) yesterday were successful.
Spacecraft temperatures remain in the acceptable range. The
transmitter peaks at 47.7 degrees C and the DMS-B (Data Management
Subsystem-B) tape recorder head reaches 32.9 degrees C, but most other
temperatures have stabilized withing the planning limits.
Yesterday, spacecraft controllers sent up new Kalman gains to be
used with star calibrations which scan a new pair of stars. Later
today, they will uplink the M1249 command sequence which begins
execution tomorrow afternoon.
The new 2-week command sequence will continue the two 20 minute
periods in each orbit where Magellan hides behind the High Gain
Antenna. This shortens the radar mapping swaths to about 65% of their
normal length. Mapping begins at about 5 degrees north latitude and
extends to the South Pole.
Magellan has now completed 2500 mapping orbits, 824 since the
start of Cycle 2. So we are 46% finished with Cycle 2.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 301-355 Telos | Good judgement comes from
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | experience. Experience
|_____|/ |_|/ |_____|/ | comes from bad judgement.
Date: 7 Sep 91 03:34:34 GMT
From: (Ron Baalke)
Subject: Magellan Update - 09/06/91
Forwarded from Anthony Spear, Magellan Project Manager
MAGELLAN STATUS REPORT
September 6, 1991
Magellan spacecraft performance continues to be excellent. Only
one star was missed during yesterday's starcals (star calibrations).
All spacecraft temperatures have stabilized in the acceptable
range. The transmitter peaks at 48 degrees C and the DMS-B (Data
Management Subsystem) tape recorder head reaches 32.9 degrees C.
Yesterday, spacecraft controllers sent up the M1249 command
sequence with its associated radar control parameter and mapping
quaternion files.
The new 2-week command sequence will continue the two 20 minute
cooling periods in each orbit, shortening the radar mapping swaths to
about 65% of their normal length.
Mapping begins at about 5 degrees north latitude and extends to
the South Pole. One of the principal features being imaged right
looking is Artemis Chasma in the south central part of Aphrodite.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 301-355 Telos | Good judgement comes from
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | experience. Experience
|_____|/ |_|/ |_____|/ | comes from bad judgement.
|
| 456.375 | Update - September 9 | MTWAIN::KLAES | All the Universe, or nothing! | Tue Sep 10 1991 12:46 | 34 |
| Date: 10 Sep 91 03:27:24 GMT
From: (Ron Baalke)
Subject: Magellan Update - 09/09/91
Forwarded from Anthony Spear, Magellan Project Manager
MAGELLAN STATUS REPORT
September 9, 1991
Magellan spacecraft performance continues to be excellent. Two
stars were missed during the first orbits of the new sequence on
Friday during the day which was caused by the several changes in the
new sequence including new star pairs.
All spacecraft temperatures have stabilized in the acceptable
range. The transmitter peaks at 48 degrees C and the DMS-B (Data
Management Subsystem-B) tape recorder head reaches 32.9 degrees C.
Today, spacecraft controllers will send up a new Radar Control
Parameter File. The on-board command sequence will continue the two
20-minute cooling periods in each orbit, shortening the radar mapping
swaths to about 65% of their normal length.
Mapping begins at about 5 degrees north latitude and extends to
the South Pole. The spacecraft continues to image right looking
Artemis Chasma which is in the south central part of Aphrodite.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 301-355 Telos | Good judgement comes from
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | experience. Experience
|_____|/ |_|/ |_____|/ | comes from bad judgement.
|
| 456.376 | Update - September 10 | MTWAIN::KLAES | All the Universe, or nothing! | Wed Sep 11 1991 12:26 | 33 |
| Date: 11 Sep 91 01:57:06 GMT
From: (Ron Baalke)
Subject: Magellan Update - 09/10/91
Forwarded from Anthony Spear, Magellan Project Manager
MAGELLAN STATUS REPORT
September 10, 1991
Magellan spacecraft performance continues to be excellent. All
STARCALS (star calibrations) were successful.
All spacecraft temperatures are holding in the acceptable range.
The transmitter peaks at 48 degrees C and the DMS-B (Data Management
Subsystem-B) tape recorder head reaches 34 degrees C.
Today, spacecraft controllers will send up a commands to change
the contents of the Delayed Engineering Data telemetry. The on-board
command sequence will continue the two 20-minute cooling periods in
each orbit, shortening the radar mapping swaths to about 65% of their
normal length.
Mapping begins at about 5 degrees north latitude and extends to
the South Pole. The spacecraft continues to image right looking
Artemis Chasma which is in the south central part of Aphrodite.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 301-355 Telos | Good judgement comes from
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | experience. Experience
|_____|/ |_|/ |_____|/ | comes from bad judgement.
|
| 456.377 | Update on Venus channel and landslide | MTWAIN::KLAES | All the Universe, or nothing! | Wed Sep 11 1991 20:01 | 79 |
| Article 16736
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.astro
Subject: Magellan Discoveries (article)
Date: 11 Sep 91 23:59:46 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Science News
September 7, 1991
Record-Breaking Revelations from Venus
By R. Cowen
Two record-breaking discoveries - unveiled in a single day - offer
compelling evidence of Venus' geologic activity, both past and present.
On the morning of August 30, researchers announced that radar
images of Venus revealed the solar system's longest channel, an
ancient trough longer than the Nile River. Hours later, at a hastily
called press conference, the same team announced an even more dramatic
finding: other images showed that Venus suffered a massive landslide
sometime in the past several months, providing the first confirmation
of current geologic activity on a planet other than Earth.
Jeffery Plaut of the Jet Propulsion Laboratory in Pasadena,
Calif., says he discovered the landslide while comparing two radar
images of Aphrodite Terra, an equatorial plateau. The Magellan
spacecraft took one of the images last November and the other in July
during its second trip around Venus. Placed side by side under a
stereoscope, the images should have merged to form a three-dimensional
view of a cliff and steeply sloping valley, with bright areas
representing the most jagged regions. But a bright patch at the base
of the valley, clearly visible in the July image, did not appear in
the earlier picture.
Plaut interprets the patch as a massive heap of rocks, roughly 1
mile wide and 4 miles long, that fell from the cliff at some point
during the eight-month interim. A third, more recent Magellan image
also shows the feature, he says.
Plaut suggest that the landslide may have been triggered by an
underground disturbance, such as a "Venusquake", or by a fracture
originating at the planet's surface. It probably released as much
energy as a magnitude 5 earthquake, he calculates. Though exciting,
the discovery that Venus continues to experience geologic upheavals
isn't surprising, he adds, since previous evidence suggest the planet
has undergone many volcanic eruptions during the past several million
years. Plaut says he expects Magellan to capture other such events as
it continues to map Venus.
Magellan's other radar revelation emerged in images taken in
August. The unusually long channel, stretching across the plains of
Venus for 4,200 miles, begins just above the equatorial highlands in a
region west of Atla Regio and follows a smoothly curving, northward
course toward a large basin called Atalanta Palnitia. Soviet
spacecraft spied sections of the trough in 1984, but only with
Magellan's higher resolution could researchers gauge its full extent,
says project scientist Steve Saunders of the Jet Propulsion Laboratory.
Magellan had previously mapped similiar, shorter channels on the
Venusian plains. Many of these terminate at lava flows, suggesting
they were carved out by molten lava from a volcanic eruption, Saunders
says. But it's difficult to understand how a lava flow could have
remained fluid long enough to create a channel as extensive as the
newly discovered one, he adds.
In a rugged terrain of ridges and impact craters, the remarkably
uniform width of this trough - which averages 1.1 miles across - poses
another puzzle, says Saunders. He speculates that the region may have
been far smoother when the lengthy channel originally formed.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 301-355 Telos | Good judgement comes from
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | experience. Experience
|_____|/ |_|/ |_____|/ | comes from bad judgement.
|
| 456.378 | | VCSESU::MOSHER::COOK | Demons fall as Angels thrive | Thu Sep 12 1991 12:42 | 2 |
|
Speaking of Venus, are there any .GIF's out there of Venus?
|
| 456.379 | Update - September 11; No landslide? | MTWAIN::KLAES | All the Universe, or nothing! | Thu Sep 12 1991 13:39 | 146 |
| Article 16738
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 09/11/91
Date: 11 Sep 91 21:58:33 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from Anthony Spear, Magellan Project Manager
MAGELLAN STATUS REPORT
September 11, 1991
The Magellan spacecraft is performing nominally. There was only
one missed star during yesterday's starcals (star calibrations) and
desats (desaturations of the reaction wheels). Attitude updates range
from 0.006 to 0.011 degree.
Yesterday, spacecraft controllers uplinked a change to the
Delayed Engineering Data to provide more visibility into temperatures.
They are also planning to change to solar panel offpoint to provide
some shading of Bay 5.
Magellan is presently mapping Venus in a right-look mode. Due to
the two 20-minute cooling periods in each orbit, the image swaths
begin at about 5 degrees north latitude and extend to the South Pole.
Magellan has recently mapped a 50-orbit area of Cycle 1 which was
partially unprocessable due to the deterioration of the on-board tape
recorder "A". The new image area recovered puts us just over the 90%
mark in our coverage of Venus.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 301-355 Telos | Good judgement comes from
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | experience. Experience
|_____|/ |_|/ |_____|/ | comes from bad judgement.
Article 16741
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Re: Is Venus landslide recanted?
Date: 11 Sep 91 23:57:45 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
In article <1991Sep11.173920.7162@athena.mit.edu>, kip@space.mit.edu
(Karolen I. Paularena) writes...
>I heard yesterday that radar processing problems (?) caused the bright
>patch which Plaut interpreted as a landslide, and that he had
>withdrawn his identification. So I was surprised to read Baalke's
>posting (not a flame!). Does anyone know from direct evidence
>whether Plaut did or did not withdraw his interpretation?
Since the announcment of the landslide discovery, a second
interpretation of the two images has come up. Since the two images
were taken at different look angles (45 degrees from vertical versus
24 degrees), it is possible that the differences between the two
images can be accounted for by what is called a layover effect, and if
this is true, then there was no landslide. The scientists are split
50-50 on this. The only way to know for sure, is to take another
image of the same area with the exact parameters used with the first
image, and then compare the two. Magellan will pass over this area
again in March of 1992.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 301-355 Telos | Good judgement comes from
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | experience. Experience
|_____|/ |_|/ |_____|/ | comes from bad judgement.
Article 16753
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Re: Magellan Landslide Images
Date: 12 Sep 91 08:35:31 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
I've written a little IMDISP batch file that will display the Magellan
landslide images rapidly in succession on top of each other,
effectively creating a blink effect. This makes it easier to see the
differences between the two images. The batch file, landslid.cmd, is
available via anonymous ftp at ames.arc.nasa.gov in the
pub/SPACE/SOFTWARE. This is also where the IMDISP program resides. A
minimum of 2MB of RAM and a 640x480 graphics board (or better) on an
IBM PC is required to properly run the batch file. The Magellan
image, landslid.img, is in the pub/SPACE/VICAR directory.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 301-355 Telos | Beware of programmers who
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | carry solder irons.
|_____|/ |_|/ |_____|/ |
Article 35478
From: hmueller@orca.tamu.edu (Hal Mueller)
Newsgroups: sci.space
Subject: Re: Is Venus landslide recanted?
Date: 11 Sep 91 22:36:06 GMT
Sender: usenet@tamsun.TAMU.EDU
Organization: Dept. of Wildlife and Fisheries Sciences, Texas A&M University
>What is a layover effect?
Range layover is the apparent dislocation of the top of a tall object
from its bottom when a SAR uses a steep grazing angle. It's the
difference between the slant ranges to the top and bottom of the object.
Consider viewing a 1000' object twice, once from the east and once
from the west, both times at a range of 1000' (measured horizontally).
RW---------- 1000' ---------- T ---------- 1000' -----------RE
X
X
X
X
(1000' elevation) X
X
X
B
In both cases, assume that the radar is flying perpendicular to the
screen, through RE/RW. The radar can't tell that the object has
height, only that the range to its top is 1000' and to its bottom
1414'. This extreme example maximizes the difference in apparent
positions of point T. From RW, T is 414' west of B, but from RE, T is
414' EAST of B. The maps would look like
RW view:
TXXXXXXXB
RE view:
BXXXXXXXT
--
Hal Mueller
hmueller@orca.tamu.edu
n270ca@tamunix.Bitnet
|
| 456.380 | | WLDBIL::KILGORE | Digital had it Then! | Thu Sep 12 1991 15:00 | 3 |
|
Could somebody explain "desaturations of the reactions wheels"?
|
| 456.381 | Explanation of desaturation | CHEST::HAZEL | Marvin the Paranoid Android was right | Thu Sep 12 1991 15:13 | 28 |
| A reaction wheel is used to turn the spacecraft around one of its axes
without firing thrusters. The idea is that if you spin the wheel one
way, the spacecraft will rotate in the opposite direction. When you
stop the wheel, the spacecraft will likewise stop turning.
However, because the spacecraft also experiences external forces which
tend to rotate it, things are a little more complex. After some time,
you will find that the spacecraft is non-rotating before the reaction
wheel has stopped spinning. If left unattended, the reaction wheel
rotation rate when the spacecraft is non-rotating will increase,
meaning that the wheel eventually ends up spinning quite fast just to
keep the spacecraft attitude constant.
To dump this excess angular momentum, you fire the thrusters so as to
keep the spacecraft non-rotating, while at the same time reducing the
spin of the reaction wheels to zero. When the wheel stops spinning, you
turn off the thrusters, and there you are: no spacecraft spin and no
reaction wheel spin. This is called desaturation (because the buildup
of spin in the reaction wheel is like saturating it with spin -
eventually it can't spin any faster).
The forces which tend to spin up the spacecraft are things like: tidal
forces from the body it is orbiting; atmospheric drag (which is rarely
symmetrical in its effect, and hence tends to rotate the spacecraft);
and various other drag forces like solar wind, radiation pressure, etc.
Dave Hazel
|
| 456.382 | I'm not a moderator of this conference, but... | PRAGMA::GRIFFIN | Dave Griffin | Thu Sep 12 1991 16:02 | 7 |
| Re: .378, .380
These topics have been answered at least twice in this note alone. Please
check previous replies (I know there are a lot of them), before asking
questions...
- dave
|
| 456.383 | Update - September 12; Images on CDROM | MTWAIN::KLAES | All the Universe, or nothing! | Fri Sep 13 1991 14:22 | 105 |
| Article 16770
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 09/12/91
Date: 13 Sep 91 01:17:36 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from Anthony Spear, Magellan Project Manager
MAGELLAN STATUS REPORT
September 12, 1991
The Magellan spacecraft is performing nominally. All starcals (star
calibrations) and desats (desaturations) yesterday were successful.
Spacecraft temperatures remain in the acceptable range. The DMS-B (Data
Management Subsystem-B) tape recorder head now reaches 35.7 degrees C, but most
other temperatures have stabilized within the planning limits.
There were no commands sent to the spacecraft yesterday, but later today
controllers will send up a routine update of the command sequence.
Magellan is mid-way through a 2-week command sequence which uses two 20
minute cooling periods in each orbit. This shortens the radar mapping swaths
to about 65% of their normal length. Mapping begins at about 5 degrees north
latitude and extends to the South Pole.
Magellan has now completed 2552 mapping orbits, 876 since the start of
Cycle 2. This Saturday will mark the halfway point in Cycle 2.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 301-355 Telos | Beware of programmers who
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | carry solder irons.
|_____|/ |_|/ |_____|/ |
Article 16779
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan CDROMS
Date: 13 Sep 91 01:37:36 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
======================
Magellan CD-ROMS
September 12, 1991
======================
Five new Magellan CD-ROMs can now be obtained from the National
Space Science Data Center (NSSDC) at the Goddard Space Flight Center.
These five along with the CD-ROM released earlier this year bring the
Magellan CD-ROM total to 6. The "nominal" charge is $20 for the first
CD-ROM, and $6 for any additional disks in an order. However, NSSDC
waives this charge for bona fide research users, teachers who indicate
that they would be unable to use the material if they were required to
pay, government laboratories, etc. Researchers funded by NASA's Solar
System Exploration Division can also obtain the disks through the
Planetary Data System at JPL.
NSSDC also provides the following software to display the images:
o IMDISP (IBM PC)
o Browser (Macintosh)
o Pixel Pusher (Macintosh)
o True Color (Macintosh)
NSSDC's address is:
National Space Science Date Center
Goddard Space Flight Center
Greenbelt, Maryland 20771
Tel: (301) 286-6695
Email address: request@nssdca.gsfc.nasa.gov
You can also reach NSSDC by logging on to their computer. To log
onto the NSSDC computer, telnet to NSSDC.GSFC.NASA.GOV [128.183.36.25]
and give the username "NSSDC". You will then be connected to a menu
system which allows you to use the "Master Directory". You can also
leave questions and orders for the NSSDC staff. If this is the first
time you have used the NSSDC "NODIS" system, it will ask you for
information (name, address, ...) to keep a database of NSSDC users.
Peter Yee at the Ames Research Center will also be making the new
Magellan CD-ROMs available via anonymous ftp at AMES.ARC.NASA.GOV
[128.102.18.3]. The Ames site has two CD-ROM drives and they are
accessible through the pub/SPACE/CDROM and pub/SPACE/CDROM2
directories. The CD-ROMs will be rotated on a weekly basis.
The Magellan project is continuing to produce CD-ROMs at the rate
of 8 per month. The current 5 CD-ROMs cover the first 21 days of
mapping, or roughly 1/10 of the planet. In October, the project will
release disks through the first 4 months, or roughly 1/2 the planet.
The full planet will be available by February in a set of about 50 disks.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 301-355 Telos | Beware of programmers who
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | carry solder irons.
|_____|/ |_|/ |_____|/ |
|
| 456.384 | Update - September 13 | MTWAIN::KLAES | All the Universe, or nothing! | Sat Sep 14 1991 15:13 | 35 |
| Article 16824
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 09/13/91
Date: 13 Sep 91 23:34:11 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from Anthony Spear, Magellan Project Manager
MAGELLAN STATUS REPORT
September 13, 1991
Magellan spacecraft performance continues to be excellent. All starcals
(star calibrations) and desats (desaturations) yesterday were successful.
All spacecraft temperatures remain in the acceptable range. The DMS-B
(Data Management Subsystem-B) tape recorder head has dropped slightly to
35 degrees C.
Today, spacecraft controllers are planning to reset the Solar Array Drive
Motor commanded position. The position as indicated by the potentiometers is
3x off from the position referenced in the on-board computer.
Orbit #3060, on Saturday, September 14th marks the halfway point in our
second cycle around Venus. Coincidentally, Sunday is the anniversary of when
we started mapping operations.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 301-355 Telos | Beware of programmers who
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | carry solder irons.
|_____|/ |_|/ |_____|/ |
|
| 456.385 | Update - September 16 | MTWAIN::KLAES | All the Universe, or nothing! | Tue Sep 17 1991 16:56 | 39 |
| Article 16906
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 09/16/91
Date: 17 Sep 91 02:50:53 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from Anthony Spear, Magellan Project Manager
MAGELLAN STATUS REPORT
September 16, 1991
The Magellan spacecraft is performing nominally. On Friday, the
spacecraft experienced another spurious shutoff of the high power
transmitter, TWTA-A, during a mapping pass. The fault protection
worked perfectly, and no data was lost.
Also on Friday, spacecraft controllers reset the Solar Array
Drive Motor commanded position to adjust for slippage in the position
as indicated by the potentiometers relative to the position referenced
in the on-board computer. They also changed the Sun Loss Timer to 48
minutes.
All spacecraft temperatures remain in the acceptable range. The
Bay 7 temperature has risen about 2 degrees C, but this was expected.
Orbit #3060, on Saturday, September 14th marked the halfway point
in our second cycle around Venus. Each cycle is 243 earth days, the
time it takes Venus to turn once on its axis. Cycle 2 will end on
January 14, 1992.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 301-355 Telos | Beware of programmers who
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | carry solder irons.
|_____|/ |_|/ |_____|/ |
|
| 456.386 | Update - September 17 | MTWAIN::KLAES | All the Universe, or nothing! | Wed Sep 18 1991 20:08 | 35 |
| Article 16941
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 09/17/91
Date: 18 Sep 91 00:30:58 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from Anthony Spear, Magellan Project Manager
MAGELLAN STATUS REPORT
September 17, 1991
The Magellan spacecraft is performing nominally.
On Monday, a normal Radar Control Parameter File was sent to the
spacecraft successfully.
Also on Monday, a command was approved which will provide an
increase sampling of the +X solar array telemetry to facilitate
diagnosis of SADM (Solar Array Drive Mechanism) slip. This command
will be sent to the spacecraft on Wednesday.
All spacecraft temperatures remain in the acceptable range. The
Bay 7 temperature which contains CDS (Command Data Subsystem) now
peaks at 54.9 degrees C and DMS-B (Data Management Subsystem-B) head
temperature peaks at 35 degrees C.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 301-355 Telos | Beware of programmers who
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | carry solder irons.
|_____|/ |_|/ |_____|/ |
|
| 456.387 | Update - September 18 | MTWAIN::KLAES | All the Universe, or nothing! | Thu Sep 19 1991 12:08 | 28 |
| Article 16969
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 09/18/91
Date: 19 Sep 91 03:47:33 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from Anthony Spear, Magellan Project Manager
MAGELLAN STATUS REPORT
September 18, 1991
The Magellan spacecraft is performing nominally. No commands were sent
yesterday. All star scans were successful.
All spacecraft temperatures remain in the acceptable range. The Bay 7
temperature which contains CDS (Command Data Subsystem) now peaks at 54.9
degrees C and DMS-B (Data Management Subsystem) head temperature peaks at
35 degrees C.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 301-355 Telos | Beware of programmers who
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | carry solder irons.
|_____|/ |_|/ |_____|/ |
|
| 456.388 | Update - September 19 | MTWAIN::KLAES | All the Universe, or nothing! | Fri Sep 20 1991 14:39 | 55 |
| Article 17009
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 09/19/19
Date: 20 Sep 91 00:06:03 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from:
PUBLIC INFORMATION OFFICE
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIF. 91109. TELEPHONE (818) 354-5011
MAGELLAN STATUS REPORT
September 19, 1991
The Magellan spacecraft is performing normally. Wednesday night,
one star scan was only partially successful. All others were fine.
One command was sent Wednesday to gather more solar array data.
The data will be used to gain some insight into a solar array slippage
problem. Earlier, controllers had reset the solar array drive motor
commanded position to adjust for slippage when it was found the
position did not match the on-board computer's reference.
All spacecraft temperatures remain in the acceptable range.
######
Forwarded from Anthony Spear, Magellan Project Manager
MAGELLAN STATUS REPORT
September 19, 1991
The Magellan spacecraft is performing nominally.
One command was sent Wednesday morning to change one of the
telemetry support fields to gather more solar array data. This data
will be used to gain some insight into the solar array slippage problem.
During Wednesday night one star scan was only partially
successful. All others were fine.
All spacecraft temperatures remain in the acceptable range, with
no change from the previous day.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 301-355 Telos | Beware of programmers who
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | carry solder irons.
|_____|/ |_|/ |_____|/ |
|
| 456.389 | Update - September 20 | MTWAIN::KLAES | All the Universe, or nothing! | Sun Sep 22 1991 19:34 | 30 |
| Article 17044
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 09/20/91
Date: 21 Sep 91 03:15:36 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from Anthony Spear, Magellan Project Manager
MAGELLAN STATUS REPORT
September 20, 1991
The Magellan spacecraft is performing nominally.
The next mapping sequence, M1263, was uplinked Thursday night. This
sequence is set to go active today at 2:30 p.m. PDT.
All star scans were successful over the last 24 hours.
All spacecraft temperatures remain in the acceptable range, with Bay 7
lowering .7 degree from the previous day.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 301-355 Telos | Beware of programmers who
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | carry solder irons.
|_____|/ |_|/ |_____|/ |
|
| 456.390 | More Magellan images, courtesy JPL | PRAGMA::GRIFFIN | Dave Griffin | Thu Sep 26 1991 04:13 | 17 |
| Eighteen new images from the Magellan CDROMs are available, plus two
images of the questioned landslide.
All images are in pragma::public:[nasa]
The CDROM mosaics are of the form:
MGN_aaXbbb.GIF
Where: aa is latitude, X is N[orth] or S[outh]
bbb is longitude
The landslide images (one is just a smaller form of the other):
MGN_Landslide_n.GIF (n=1,2)
- dave
|
| 456.391 | Updates - September 24-27 | MTWAIN::KLAES | All the Universe, or nothing! | Sun Sep 29 1991 16:36 | 258 |
| Article 17124
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 09/24/91
Date: 25 Sep 91 03:18:26 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from Anthony Spear, Magellan Project Manager
MAGELLAN STATUS REPORT
September 24, 1991
The Magellan spacecraft is performing nominally. All starcals (star
calibrations) yesterday were successful, with only one missed star.
Since Friday the spacecraft has been operating under the M1263 command
sequence. This sequence includes two 22-minute cooling periods in each orbit,
and offpointing of the solar panels for thermal control.
The solar panel drive mechanism continues to experience a slippage,
resulting in a difference of several degrees in the position indicated by the
potentiometers as compared to the commanded position shown in the on-board
computer. For example, this difference increased by 2-1/2 degrees in the last
24 hours.
The problem, which has been observed for nearly a year, is more noticable
when the orbit geometry requires greater movement of the solar arrays. The
spacecraft controllers have corrected the difference by adjusting the commanded
position in the on-board computer to match the actual position. Normally this
correction is made when the slippage approaches a few degrees.
So later today, controllers will send up the correction to the Solar Array
Drive Mechanism (SADM) commanded position.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 301-355 Telos | Beware of programmers who
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | carry solder irons.
|_____|/ |_|/ |_____|/ |
Article 17142
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 09/25/91
Date: 26 Sep 91 00:42:03 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from Anthony Spear, Magellan Project Manager
MAGELLAN STATUS REPORT
September 25, 1991
The Magellan spacecraft is performing nominally. There were two
missed stars during yesterday's starcals (star calibrations) and
desats (desaturation of the reaction wheels).
Yesterday, at about 9:00 AM (PDT), spacecraft controllers noticed
that the slip rate on the solar array drive mechanism (SADM) had
increased to 4 degrees in the past 24 hours. At this rate it was
likely to trigger the on-board fault protection.
They were unable to send up commands to reset the referenced
position or to disable the SADM control loss fault protection because
the spacecraft was starting a new mapping pass.
As a result, Magellan did an IODA swap (changing from one
Input-Output Drive Assembly to its backup). The spacecraft continued
mapping, and when two-way communications resumed, the controllers
disabled the SADM control loss fault protection and reset other fault
protection parameters.
All systems appear nominal, and the SADM slip has gone back to
its previous rate.
Magellan continues to map Venus in a right-look, constant
incidence angle mode. Due to the two 22-minute cooling periods in
each orbit, the image swaths begin at about 2.5 degrees south latitude
and extend to the South Pole.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 301-355 Telos | Beware of programmers who
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | carry solder irons.
|_____|/ |_|/ |_____|/ |
Article 17159
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update #2 - 09/26/91
Date: 27 Sep 91 04:27:07 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from Anthony Spear, Magellan Project Manager
MAGELLAN STATUS REPORT
September 26, 1991
The Magellan spacecraft is performing nominally. There were two
missed stars during yesterday's starcals (star calibrations) and
desats (desaturations).
All systems appear nominal, and the SADM (Solar Array Drive Mechanism)
slip has gone back to its previous rate.
Magellan continues to map Venus in a right-look, constant incidence angle
mode. Due to the two 22-minute cooling periods in each orbit, the image swaths
begin at about 2.5 degrees south latitude and extend to the South Pole.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 301-355 Telos | Beware of programmers who
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | carry solder irons.
|_____|/ |_|/ |_____|/ |
Article 17160
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 09/26/91
Date: 27 Sep 91 04:23:58 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded:
PUBLIC INFORMATION OFFICE
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIF. 91109. TELEPHONE (818) 354-5011
MAGELLAN STATUS REPORT
September 26, 1991
The Magellan spacecraft is performing normally, but there were
two missed star calibrations during Wednesday's starcals.
Magellan continues to map Venus looking to its right and with a
constant angle. Due to two 22-minute cooling periods in each orbit,
the image swaths begin at about 2.5 degrees south latitude and extend
to the south pole. That represents an additional four minutes of lost
transmission time. Earlier, the spacecraft was hiding behind its
high-gain antenna for two 20-minute periods to prevent solar heating
of the instruments.
The slip rate in the solar array drive mechanism increased to 4
degrees earlier this week. That is, there was a 4 degree difference
between the actual angle of the solar array and the information
contained in the on-board computer. Controllers sent up new commands
to disable the drive mechanism's fault protection and set new fault
protection parameters.
Today, the solar array was back to normal.
#####
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 301-355 Telos | Beware of programmers who
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | carry solder irons.
|_____|/ |_|/ |_____|/ |
Article 17175
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: New Magellan Images Released
Date: 27 Sep 91 20:42:26 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Paula Cleggett-Haleim
Headquarters, Washington, D.C. September 27,1991
(Phone: 202/453-1547)
Jim Doyle
Jet Propulsion Laboratory, Pasadena, Calif.
(Phone: 818/354-5011)
N91-67
NOTE TO EDITORS: NEW MAGELLAN IMAGES RELEASED
Two new images released by NASA today show that Venus is even
more torn by tectonic forces than had been thought before the Magellan
mapping began. According to Dr. Steve Saunders, Magellan Project
Scientist at NASA's Jet Propulsion Laboratory, Pasadena, Calif., the
planet's dynamic nature is becoming increasingly evident with more
than 90 percent of Venus now mapped by the Magellan spacecraft over
the past 377 days. He describes Earth's nearest planetary neighbor as
a planet of searing winds, violent crustal deformations and giant
volcanic eruptions,
One full-resolution radar image shows the Akna Montes (mountains)
on the west side of the elevated smooth plateau Lakshmi Planum
(plains), which were formed by extensive volcanic eruptions and is
surrounded by mountains. The image also shows an impact crater named
Wanda which appears to have been made after the Akna mountains formed.
The western ridge of the crater has collapsed onto its floor.
Another image shows the Danu mountains to the south of the
Lakshmi Planum and a circular volcanic dome 12 miles in diameter. The
southern part of the dome has been deformed by the tectonic processes
which created the mountains.
"These mountains appear to have been formed by uplift resulting
from compression," Saunders said. "All around the high plains, the
volcanic plains surface is folded and faulted at the base of the
mountains."
The two black & white images to illustrate this release, numbers
91-H-746 and 91-H-747, are available to news media representatives by
calling the NASA Broadcast and Audio-Visual Branch at 202/453-8375.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 301-355 Telos | For every rule, there is
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | an exception. There is no
|_____|/ |_|/ |_____|/ | exception to this rule.
Article 17179
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 09/27/91
Date: 27 Sep 91 21:55:41 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from Anthony Spear, Magellan Project Manager
MAGELLAN STATUS REPORT
September 27, 1991
Magellan spacecraft performance continues to be excellent. All starcals
(star calibrations) and desats (desaturations) yesterday were successful. All
spacecraft temperatures remain in the acceptable range, essentially unchanged
in the past two days.
Yesterday, spacecraft controllers sent up the normal updates to the
mapping quaterion polynomials and radar control parameters. No commanding is
planned from today through Monday.
Magellan has now completed 2662 mapping orbits of Venus. In the present
mapping mode, each orbit returns an image swath which extends from just below
the equator to the South Pole. Each swath is about 14 miles wide and 6000
miles long.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 301-355 Telos | For every rule, there is
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | an exception. There is no
|_____|/ |_|/ |_____|/ | exception to this rule.
|
| 456.392 | Update - October 1 | MTWAIN::KLAES | All the Universe, or nothing! | Wed Oct 02 1991 12:49 | 103 |
| Date: 2 Oct 91 02:57:44 GMT
From: (Ron Baalke)
Subject: Magellan Update - 10/01/91
Forwarded from Anthony Spear, Magellan Project Manager
MAGELLAN STATUS REPORT
October 1, 1991
The Magellan spacecraft is performing nominally. All starcals (star
calibrations) yesterday were successful, with only one missed star.
The spacecraft continues to operate under the M1263 command
sequence which includes two 22-minute cooling periods in each orbit,
and offpointing of the solar panels for thermal control.
Last night there was another spurious shutoff (SSO) of the high power
transmitter, TWTA-A. This is the 15th SSO. The on-board fault protection
restored normal operation very quickly and no radar data was lost.
Later today controllers will begin reconfiguring some of the
spacecraft parameters in preparation for the uplink of command
sequence M1277 on Friday. This sequence will include a radio science
experiment to be performed on Saturday, Oct. 5.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 301-355 Telos | For every rule, there is
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | an exception. There is no
|_____|/ |_|/ |_____|/ | exception to this rule.
Date: 2 Oct 91 09:18:51 GMT
From: (Ron Baalke)
Subject: Yet More Magellan Images
===================
MAGELLAN IMAGES
October 1, 1991
===================
The Magellan project released two new images last week (refer to
press release N91-67), and I've placed the two images at the Ames
SPACE archives. These new images are in VICAR format and are
obtainable via anonymous ftp from ames.arc.nasa.gov (128.102.18.3) in
the pub/SPACE/VICAR directory as files akna.img and danu.img.
akna.img 1,194,270 bytes
danu.img 1,002,000 bytes
All of the VICAR images have a corresponding caption files (with
a .txt extension) which contains detailed descriptions of the image.
I've appended the caption files to the end of this posting. Make sure
you are in binary mode when transferring the image files, and in ASCII
mode when transferring the txt files.
I've also converted the image into GIF format, and they can be
found in the pub/SPACE/GIF directory. The akna1.gif file is a closeup
of the crater called Wanda.
akna.gif 160,149 bytes
akna1.gif 360,726 bytes
danu.gif 220,139 bytes
The VICAR images can be viewed on an IBM PC computer with the
IMDISP program stored in a zip file called imdisp74.zip, located in
the pub/SPACE/SOFTWARE directory, at the same Ames site. IMDISP is
the same program distributed with the Voyager and Magellan CDROMs.
Since I am one of the programmers for IMDISP, I would welcome any
feedback on IMDISP, including any problems encountered with its use or
suggestions on improving the program. I anticipate version 7.7 of
IMDISP being released soon, so the filename may be updated to
imdisp77.zip at any time.
-----------------------------------------------------------------------------
akna.txt
akna.img shows a portion of the Akna Mountains, which form the western
edge of Lakshmi Planum. The crater Wanda has a diameter of 22 km.
While the crater does not seem deformed by tectonic activity, material
from adjacent mountain areas appear to have collapsed into it. The
ridge of mountains to the west of Wanda is about 8 km in width. The
image is about 200 km long and 125 km wide. It is centered at 71.5N
lat., 324 east long.
-----------------------------------------------------------------------------
danu.txt
danu.img is a section of the Danu Mountains, which bound Lakshmi
Planum to the south. Because of the steep slopes, local relief in
this area (2-3 km) and radar geometry, the fault-bounded troughs
appear to zig-zag through the area while they are likely straight when
viewed from above. The large volcanic dome is 20 km in diameter and
shows deformation and faulting where it has been affected by the
forces that created the Danu Mountains. This image is 75 km on a side
and is centered at 60N lat., 324.5 east long.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 301-355 Telos | For every rule, there is
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | an exception. There is no
|_____|/ |_|/ |_____|/ | exception to this rule.
|
| 456.393 | Update - October 2 | MTWAIN::KLAES | All the Universe, or nothing! | Thu Oct 03 1991 13:27 | 47 |
| Article: 17277
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 10/02/91
Date: 2 Oct 91 23:42:53 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from:
PUBLIC INFORMATION OFFICE
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIF. 91109. TELEPHONE (818) 354-5011
MAGELLAN STATUS REPORT
October 2, 1991
The Magellan spacecraft is performing normally. All star
calibrations Tuesday were successful. Temperatures have risen
slightly, as expected, in this period.
The spacecraft continues to operate under a command sequence
which includes two 22-minute cooling periods in each orbit, and
offpointing of the solar panels for thermal control.
Controllers are preparing for the uplink of a new command
sequence on Friday. The sequence will include a radar science
experiment to be performed on Saturday, October 5.
Earlier this week, there was a spurious shutoff of the high power
transmitter. It was the 15th such shutoff. The on-board fault
protection restored normal operation very quickly and no radar data
was lost.
In the present mapping mode, with two hide periods for thermal
control, each orbit returns an image which extends from just south of
the equator to the south pole. Each swath is about 14 miles wide and
6,000 miles long.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 301-355 Telos | For every rule, there is
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | an exception. There is no
|_____|/ |_|/ |_____|/ | exception to this rule.
|
| 456.394 | Update - October 3 | MTWAIN::KLAES | All the Universe, or nothing! | Fri Oct 04 1991 14:26 | 36 |
| Date: 3 Oct 91 23:10:36 GMT
From: (Ron Baalke)
Subject: Magellan Update - 10/03/91
Forwarded from Anthony Spear, Magellan Project Manager
MAGELLAN STATUS REPORT
October 3, 1991
The Magellan spacecraft is performing nominally. All starcals
(star calibrations) and desats (desaturations of the reaction wheels)
yesterday were successful.
Spacecraft temperatures remain in the acceptable range. The DMS-B
(Data Management Subsystem-B) tape recorder head now reaches 33.5
degrees C, and the CDS (Command Data Subsystem) peaks at 54 degrees C.
Spacecraft controllers updated the Kalman gains yesterday and
will perform a memory readout today to determine the exact time of the
two most recent TWTA (high power transmitter) SSO's (Spurious Shutoffs).
Late tomorrow they will uplink the M1277 command sequence.
The new 2-week command sequence is similar to what we have been
performing since early September, but uses two 25 minute cooling
periods in each orbit. This shortens the radar mapping swaths to about
54% of their normal length. Mapping begins at about 6 degrees north
latitude and extends to the South Pole. Magellan has now completed
2706 mapping orbits, 1030 since the start of Cycle 2.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 301-355 Telos | For every rule, there is
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | an exception. There is no
|_____|/ |_|/ |_____|/ | exception to this rule.
|
| 456.395 | Update - October 4; third image of moving Venus | MTWAIN::KLAES | All the Universe, or nothing! | Mon Oct 07 1991 22:15 | 104 |
| Article: 17335
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 10/04/91
Date: 5 Oct 91 04:52:31 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from Anthony Spear, Magellan Project Manager
MAGELLAN STATUS REPORT
October 4, 1991
The Magellan spacecraft is performing nominally. All starcals (star
calibrations) and desats (desaturations) yesterday were successful.
Spacecraft temperatures continue creep upward, as expected in this phase
of Cycle 2. The DMS-B (Data Management Subsystem) tape recorder head now
reaches 34.6 degrees C, about one degree above yesterday's peaks.
Spacecraft controllers uploaded the M1277 command sequence late yesterday.
It will begin execution this afternoon. They also performed a memory readout
to determine the exact time of the two most recent TWTA (high power
transmitter) SSO's (Spurious Shutoff's).
The new command sequence is a one-week sequence which uses two 25 minute
cooling periods in each orbit. This shortens the radar mapping swaths to
about 54% of their normal length. Mapping begins at about 6 degrees north
latitude and extends to the South Pole.
The results of the Magellan mission continue to reach the science
community and the general public. Jeff Plautt gave a lecture Sept. 26th to the
San Fernando Chapter of the American Society of Materials, and Jeff Miller
spoke on Magellan at the IEEE International SOI Conference in Vail, Colorado on
October 1st.
The distribution of mosaicked photo-products is progressing. 227 MIDRs
(Mosaicked Image Data Record) have been shipped by DMAT (Data Management and
Archive Team) to the National Space Science Data Center and the Regional
Planetary Image Facilities.
Digital compact disks, containing mosaicked images from the first
four months of Cycle 1 have been delivered to the Radar Investigations
Group. Most of the 22 CD-ROMs will be approved for distribution to
scientists in October. The next 26 CD-ROMS, containing the second four
months of images, will be delivered in late 1991 and early 1992. Ten
CD-ROMs containing the altimetry and radiometer data will start
production in October.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 301-355 Telos | For every rule, there is
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | an exception. There is no
|_____|/ |_|/ |_____|/ | exception to this rule.
Article: 17347
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.astro
Subject: Re: A *third* Magellan picture of the suspected landslide region?
Date: 7 Oct 91 20:25:09 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
In article <2453@mpirbn.mpifr-bonn.mpg.de>,
p515dfi@mpirbn.mpifr-bonn.mpg.de (Daniel Fischer) writes...
>Sky & Telescope claims in its Nov.1991 issue on page 463, regarding the
>suspected landslide on Venus, in a caption to the two well-known radar
>pictures of what looks like the first change detected on this planet (but
>what others think could be a radar illumination artefact):
>
>] A third image of the area, not shown here, virtually rules out the
>] possibility that the feature is an illusion caused by the illumination
>] angle of the spacecraft's radar system.
>
>Is that true? When was that picture taken - and what does it show? The latest
>info available from printed media (esp. AW&ST) as well as Ron Baalke was that
>about 50% of the Magellan scientists thought it was a real change, the other
>half thought it was a layover artefact. Noone ever mentioned a third picture
>or even the possibility that there could be one. How could Magellan have made
>it, given it's prescribed orbit around the planet? The only way I could
>think of would have been taking another picture of the interesting region from
>a very slant angle in a special attempt to see it again - but if that would
>have taken place, it would have been a major event for the s/c, so why would
>only S&T have learned about it? So I suspect that the editors mistook the
>remark that a third picture is badly needed as a hint that it already exists.
There is a third image, and it was taken about 3 hours after July 1991
image (the second image). Each of the orbital strip images taken by
Magellan overlap each other, and it just so happened that the
landslide area was in the overlap area of two adjacent strips. So,
there are two nearly identical images of the landslide area taken in
July 1991. The third image only proved that something was definitely
there, but the general consensus among the Magellan scientists now is
that it is a layover effect.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 301-355 Telos | For every rule, there is
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | an exception. There is no
|_____|/ |_|/ |_____|/ | exception to this rule.
|
| 456.396 | Update - October 7-8 | MTWAIN::KLAES | All the Universe, or nothing! | Wed Oct 09 1991 13:34 | 75 |
| Article: 17368
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 10/07/91
Date: 8 Oct 91 23:17:02 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from Anthony Spear, Magellan Project Manager
MAGELLAN STATUS REPORT
October 7, 1991
The Magellan spacecraft is performing well. All systems are
nominal and performing as expected for this phase of the mission.
On Friday, the spacecraft began execution of the M1277 command
sequence. This one-week sequence is very similar to the prior 2-week
sequence, except that the two cooling periods in each orbit have been
increased to 25 minutes.
On Saturday, Magellan performed a radio science experiment in
which the High Gain Antenna was maneuvered to adjust for the
refraction of the radio signal as the craft passed behind Venus as
viewed from Earth. The three orbit experiment returned excellent data
and did not interrupt the radar mapping.
This gives a very precise measure of the atmospheric density at
various levels above the surface. Scientists are looking at changes
from previous atmospheric measurements, especially in the amount of
sulfuric acid, as an indication of changes in volcanic activity on the
planet.
Later today, controllers will send up the routine update to the
radar control parameter file.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 301-355 Telos | For every rule, there is
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | an exception. There is no
|_____|/ |_|/ |_____|/ | exception to this rule.
Article: 17370
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 10/08/91
Date: 8 Oct 91 23:20:09 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from Anthony Spear, Magellan Project Manager
MAGELLAN STATUS REPORT
October 8, 1991
The Magellan spacecraft is performing nominally. All starcals
(star calibrations) yesterday were successful and temperatures are
remaining stable at acceptable levels.
Yesterday, spacecraft controllers sent up the weekly update to
the radar control parameters. No commanding is scheduled for today.
Magellan is continuing to map Venus in a right-look mode,
covering the area from 6 degrees south latitude to the South Pole in
the eastern portion of Aphrodite Terra near 180 degrees longitude. It
has completed 2,743 mapping orbits.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 301-355 Telos | For every rule, there is
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | an exception. There is no
|_____|/ |_|/ |_____|/ | exception to this rule.
|
| 456.397 | Update - October 9 | MTWAIN::KLAES | All the Universe, or nothing! | Thu Oct 10 1991 16:08 | 42 |
| Article: 17407
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 10/09/91
Date: 10 Oct 91 04:11:07 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from:
PUBLIC INFORMATION OFFICE
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIF. 91109. TELEPHONE (818) 354-5011
MAGELLAN STATUS REPORT
October 9, 1991
The Magellan spacecraft is performing normally. All star
calibrations Tuesday were successful.
The spacecraft continues to operate under a command sequence
which includes two 25-minute cooling periods in each orbit, and
offpointing of the solar panels, for thermal control.
Another command sequence will be uplinked tomorrow to begin
execution Friday. The two-week sequence also has two cooling periods
in each orbit and they will be of 30 minutes each, but one period will
be shortened to 25 minutes to begin mapping early.
The longer mapping swath strategy was designed to map a feature
on Venus called Maat Mons. The Magellan scientists are especially
interested in that area of canyons and domes, centered on the equator
in the eastern part of Aphrodite Terra.
_____
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 301-355 Telos | For every rule, there is
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | an exception. There is no
|_____|/ |_|/ |_____|/ | exception to this rule.
|
| 456.398 | Update - October 10 | MTWAIN::KLAES | All the Universe, or nothing! | Fri Oct 11 1991 14:01 | 39 |
| Article: 17418
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 10/10/91
Date: 11 Oct 91 02:51:41 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from Anthony Spear, Magellan Project Manager
MAGELLAN STATUS REPORT
October 10, 1991
The Magellan spacecraft is performing nominally. All starcals (star
calibrations) yesterday were successful.
The spacecraft continues to operate under the M1277 command sequence
which includes two 25-minute cooling periods in each orbit, and offpointing
of the solar panels for thermal control.
Late tomorrow, controllers will uplink command sequence M1284 which will
begin execution on Friday. This sequence is a 2-week sequence and will include
two cooling periods in each orbit.
The cooling periods are nominally 30 minutes each, but the first is being
shortened to 25 minutes in order to begin mapping early. The five minutes has
been added to the second cooling period.
The early turn to mapping was added to the sequence in order to map a
feature on Venus called Maat Mons. This interesting area of canyons and domes
is centered on the equator in the eastern part of Aphrodite Terra.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 301-355 Telos | For every rule, there is
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | an exception. There is no
|_____|/ |_|/ |_____|/ | exception to this rule.
|
| 456.399 | Update - October 11 | MTWAIN::KLAES | All the Universe, or nothing! | Mon Oct 14 1991 21:43 | 37 |
| Article: 17449
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 10/11/91
Date: 12 Oct 91 03:05:35 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from Anthony Spear, Magellan Project Manager
MAGELLAN STATUS REPORT
October 11, 1991
The Magellan spacecraft is performing nominally. All starcals
(star calibrations) yesterday were successful.
Controllers uplinked command sequence M1284 which will begin
execution today. This sequence is a 2-week sequence and will include
two cooling periods in each orbit.
Controllers also uplinked an AACS (Attitude and Articulation
Control Subsystem) telemetry support field data gathering change to
better characterize body rates seen in the solar array drive mechanism
slip situation. The original command file specified the wrong data to
be gather and was regenerated and uplinked successfully the second time.
The solar panel power performance and pointing continues to be nominal.
Magellan has now completed 2765 mapping orbits, 1089 since the
start of Cycle 2.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 301-355 Telos | For every rule, there is
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | an exception. There is no
|_____|/ |_|/ |_____|/ | exception to this rule.
|
| 456.400 | Update - October 14 | MTWAIN::KLAES | All the Universe, or nothing! | Tue Oct 15 1991 16:39 | 37 |
| Article: 17477
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 10/14/91
Date: 15 Oct 91 03:21:35 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from Anthony Spear, Magellan Project Manager
MAGELLAN STATUS REPORT
October 14, 1991
The Magellan spacecraft performance is excellent. All starcals
(star calibrations) during the weekend were successful. The SSO
(Spurious Shutoff) counter incremented by two yesterday indicating two
brief shutoffs of the high power transmitter, but no data was lost.
Magellan is operating under a command sequence which includes two
30-minute cooling periods, but the first is being shortened to 25
minutes in order to begin mapping early. The five minutes has been
added to the second cooling period.
The early turn to mapping was added to the sequence in order to
map a feature on Venus called Maat Mons, a young volcanic feature
which may be the site of present or recent surface forming activity.
The early turn shifts the swath about 17 degrees north, starting
near the equator and ending at 83 degrees south latitude.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 301-355 Telos | For every rule, there is
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | an exception. There is no
|_____|/ |_|/ |_____|/ | exception to this rule.
|
| 456.401 | Update - October 15 | MTWAIN::KLAES | All the Universe, or nothing! | Wed Oct 16 1991 19:05 | 32 |
| Article: 17504
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 10/15/91
Date: 16 Oct 91 04:41:03 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from Anthony Spear, Magellan Project Manager
MAGELLAN STATUS REPORT
October 15, 1991
The Magellan spacecraft is performing nominally. All starcals
(star calibrations) yesterday were successful and temperatures are
remaining stable at acceptable levels.
Yesterday, spacecraft controllers sent up an update to the radar
control parameters, and will send another update later today in order
to optimize the radar performance while mapping the volcano Maat Mons.
Magellan is continuing to map Venus in a right-look mode,
covering the area from the equator to about 83 degrees south latitude
in the eastern portion of Aphrodite Terra.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 301-355 Telos | Everything should be as
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | simple as possible, but no
|_____|/ |_|/ |_____|/ | simpler. --Albert Einstein
|
| 456.402 | Update - October 16 | MTWAIN::KLAES | All the Universe, or nothing! | Thu Oct 17 1991 15:47 | 40 |
| Article: 17533
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 10/16/91
Date: 17 Oct 91 02:22:56 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from Anthony Spear, Magellan Project Manager
MAGELLAN STATUS REPORT
October 16, 1991
The Magellan spacecraft is performing nominally. All starcals
(star calibrations) yesterday were successful.
The spacecraft continues to operate under the M1284 command sequence
which includes cooling periods of 25 and 35 minutes in each orbit.
Yesterday, spacecraft controllers performed another update of the
radar control parameters to optimize the mapping of Maat Mons. This
morning they are sending up commands to remove the solar panel
offpoint. For the past series of weeks the panels have been tilted 45
degrees away from the sun line during the mapping pass in order to
reduce the amount of electrical power being produced.
The solar panels are designed to produce more electrical energy
than is needed for the spacecraft and radar. The excess is dissipated
in the form of heat through the shunt radiator. During this period of
adverse thermal conditions, it was better to reduce the sources of
heat to keep the cooling periods as short as possible and maximize the
radar mapping swaths.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 301-355 Telos | Everything should be as
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | simple as possible, but no
|_____|/ |_|/ |_____|/ | simpler. --Albert Einstein
|
| 456.403 | Magellan Status Reports 10/17/91, 10/18/91, 10/21/91 | PRAGMA::GRIFFIN | Dave Griffin | Mon Oct 21 1991 21:32 | 87 |
| MGN REPORT 10/17
AJS
10-17-91
9:00 AM
MAGELLAN STATUS REPORT
1. The Magellan spacecraft is performing nominally. Starcals
continue to be very successful, with only one partial
update in the past week.
2. The spacecraft continues to operate under the M1284
command sequence which includes cooling periods of 25 and
35 minutes in each orbit.
3. Yesterday controllers sent up commands to remove the solar
panel offpoint. We are now in a period of increasing
solar occultations; that is, Magellan is passing into the
shadow of Venus on each orbit. So temperatures are
moderating and the spacecraft needs full solar panel
output while in the sunlight.
4. The S/C Team reports that the Solar Array Drive Mechanism
slip, which had averaged about 0.5 degree per day, has now
dropped to zero. Tomorrow they plan to reset the SADM
commanded position and re-enable the SADM control loss
fault protection.
MGN REPORT 10/18
AJS
10-18-91
9:00 AM
MAGELLAN STATUS REPORT
1. The Magellan spacecraft is performing nominally. Starcals
continue to be very successful, with only one partial
update in the past week.
2. The temperature of Bay 7 on the spacecraft, containing the
CDS, is reported at 48.6xC with a cycle depth of 10.5xC.
3. The spacecraft continues to operate under the M1284
command sequence which includes cooling periods of 25 and
35 minutes in each orbit.
4. Yesterday controllers sent up the routine "tweak," with an
update to the Mapping Quaternion Polynomial Coefficients
file Today they plan to reset the SADM commanded position
and re-enable the SADM control loss fault protection.
MGN REPORT 10/21
AJS
10-21-91
9:00 AM
MAGELLAN STATUS REPORT
1. The Magellan spacecraft is performing nominally. Starcals
continue to be very successful, with only two partial
updates over the weekend.
2. The temperature of Bay 7 on the spacecraft, containing the
CDS, is reported at 48.6xC with a cycle depth of slightly
less than 12xC.
3. The spacecraft continues to operate under the M1284
command sequence which includes cooling periods of 25 and
35 minutes in each orbit.
4. Last Friday, commands were sent to the spacecraft to reset
the SADM commanded position and re-enable the SADM control
loss fault protection. Today, a new RCPF will be uplinked
|
| 456.404 | Updates - October 22-23 | MTWAIN::KLAES | All the Universe, or nothing! | Thu Oct 24 1991 19:48 | 67 |
| Article: 17781
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 10/22/91
Date: 24 Oct 91 06:42:06 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from Anthony Spear, Magellan Project Manager
MAGELLAN STATUS REPORT
October 22, 1991
The Magellan spacecraft is performing nominally. Magellan is continuing
to map Venus in a right-look mode, covering the area from the equator to
about 80 degrees south latitude in the eastern portion of Aphrodite Terra.
The spacecraft is in a period of increasing sun occultations; that is, it
is passing deeper into the shadow of Venus. This helps to lower the
temperatures of critical units. As a result of the sun occultations, the time
spent hiding in the shadow of the High Gain Antenna will be reduced during the
next four weeks.
Command sequence M1298, which will begin execution on Friday, will include
two 25-minute cooling periods.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 301-355 Telos | Everything should be as
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | simple as possible, but no
|_____|/ |_|/ |_____|/ | simpler. --Albert Einstein
Article: 17782
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 10/23/91
Date: 24 Oct 91 06:43:28 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from Anthony Spear, Magellan Project Manager
MAGELLAN STATUS REPORT
October 23, 1991
The Magellan spacecraft is performing nominally. All starcals (star
calibrations) yesterday were successful.
The spacecraft continues to operate under the M1284 command sequence
which includes cooling periods of 25 and 35 minutes in each orbit.
The spacecraft is in a period of increasing sun occultations;
that is, it is passing deeper into the shadow of Venus. This helps to
lower the temperatures of critical units.
Command sequence M1298 will begin execution on Friday. As a
result of the sun occultations, the time spent hiding in the shadow of
the High Gain Antenna will be reduced to 25 minutes.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 301-355 Telos | Everything should be as
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | simple as possible, but no
|_____|/ |_|/ |_____|/ | simpler. --Albert Einstein
|
| 456.405 | Magellan science briefing set for October 29th | PRAGMA::GRIFFIN | Dave Griffin | Thu Oct 24 1991 20:22 | 23 |
| Paula Cleggett-Haleim
NASA Headquarters, Washington, D.C. October 24, 1991
EDITORS NOTE: N91-73
Recent scientific discoveries from the Magellan mission will be
presented at a news conference Tuesday, Oct. 29, at 1 p.m. ET in the NASA
Headquarters auditorium, 400 Maryland Ave., S.W., Washington, D.C. Stereo
imagery of Venus' surface, a new global image view and a new three-
dimensional perspective video will be presented.
Speakers will include Dr. Wes Huntress, Director of NASA's Solar
System Exploration Division; Dr. Steve Saunders, Magellan Project
Scientist; Dr. John Wood, Smithsonian Astrophysical Observatory; Dr.
Gordon Pettengill, Massachusetts Institute of Technology.
A 2-minute video will be played at the end of the briefing. After the
briefing, the new Magellan photographs will be available from the Audio
Visual Branch, room 6035.
The briefing will be carried live on NASA Select television, Satcom
F2R, transponder 13, C-band, 72 degrees west longitude, frequency 3960
MHz.
|
| 456.406 | Update - October 24 | MTWAIN::KLAES | All the Universe, or nothing! | Fri Oct 25 1991 19:23 | 59 |
| Article: 17809
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 10/24/91
Date: 25 Oct 91 04:18:14 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from:
PUBLIC INFORMATION OFFICE
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIF. 91109. TELEPHONE (818) 354-5011
MAGELLAN STATUS REPORT
October 24, 1991
The Magellan spacecraft is performing normally. All star
calibrations Tuesday were successful.
The spacecraft continues to operate under a command sequence which
includes one 25-minute and one 35-minute cooling period in each orbit.
The spacecraft is in a period of increasing sun occultations;
that is, it is passing deeper into the shadow of Venus. That helps to
lower the temperatures of critical units.
A new command sequence will begin execution Friday, Oct. 25. As a
result of the sun occultations, the time spent hiding in the shadow of
the high-gain antenna will be reduced by 10 minutes -- to two
25-minute periods in each orbit.
_____
Forwarded from Anthony Spear, Magellan Project Manager
MAGELLAN STATUS REPORT
October 24, 1991
The Magellan spacecraft is performing nominally. Starcals (star
calibrations) continue to be very successful, with only one partial
update yesterday.
The spacecraft is nearing the end of the M1284 command sequence
which had cooling periods of 25 and 35 minutes in each orbit.
Late today, controllers will send up the M1298 command sequence
which will control the spacecraft for the next two weeks. It will
include two 25-minute cooling periods in each orbit. The sequence
will also return to mapping swaths which begin about 5 degrees south
of the equator and extend to the South Pole.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 301-355 Telos | Everything should be as
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | simple as possible, but no
|_____|/ |_|/ |_____|/ | simpler. --Albert Einstein
|
| 456.407 | MAGELLAN Venus Maps to be released | MTWAIN::KLAES | All the Universe, or nothing! | Mon Oct 28 1991 18:56 | 65 |
| Article: 17881
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Large Scale Maps of Venus to be Released
Date: 28 Oct 91 21:48:33 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Paula Cleggett-Haleim
Headquarters, Washington, D.C. October 28, 1991
(Phone: 202/453-1547)
Jim Doyle
Jet Propulsion Laboratory, Pasadena, Calif.
(Phone: 818/354-5011)
RELEASE: 91-177
LARGE SCALE MAPS OF VENUS TO BE RELEASED
Large-scale hemispheric maps of Venus will be released at a news
conference at NASA Headquarters, Washington, D.C., at 1 p.m. EST,
Tuesday, Oct. 29. The maps were made from the radar data acquired by
the Magellan spacecraft in its first, 8-month long, mapping cycle.
The processing of the "cycle 1" data sets, for both imagery and
altimetry, was completed recently.
Magellan Project Scientist Dr. Steve Saunders, Jet Propulsion
Laboratory, Pasadena, Calif., also will show a three-dimensional
perspective video at the press briefing. The video illustrates the
fractured and rifted terrain of Venus.
Dr. John Wood, Smithsonian Astrophysical Observatory, one of the
Magellan science team members who has studied rock weathering on
Venus, will discuss the volcano Maat Mons, which he says may be of
very recent origin.
"The Magellan test stereo data appear to be the best radar stereo data
ever obtained by any program," Saunders said. Saunders will discuss
the images and release a new stereo image along with the video and
other products.
Other members of the science team will present results of a radio
occultation experiment that looked at the planet's atmosphere using
the spacecraft's radio signal. Saunders said the radio science data
looks very "clean" and will provide information about the distribution
of sulfuric acid vapor down to about 20.5 miles above the surface, much
lower than previous spacecraft experiments have been able to measure.
Dr. Gordon Pettengill, Massachusetts Institute of Technology Principal
Investigator for the radar experiment, will discuss completion of the
global Venus altimetry and radiometry data sets from Magellan's first
mapping cycle.
The news conference will be carried live on NASA Select Television.
The Jet Propulsion Laboratory manages the Magellan Project for NASA's
Office of Space Science and Applications.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 301-355 Telos | Everything should be as
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | simple as possible, but no
|_____|/ |_|/ |_____|/ | simpler. --Albert Einstein
|
| 456.408 | Availability? | CRATE::HAZEL | Marvin the Paranoid Android was right | Tue Oct 29 1991 05:22 | 5 |
| Does anyone know when (or if) these maps will become generally
available to the public? In particular, will they be for sale outside
the US?
Dave Hazel
|
| 456.409 | Some info on the radar maps | MTWAIN::KLAES | All the Universe, or nothing! | Tue Oct 29 1991 10:45 | 53 |
| Article: 17903
From: pgf@space.mit.edu (Peter G. Ford)
Newsgroups: sci.astro
Subject: Re: Large Scale Maps of Venus to be Released
Date: 29 Oct 91 05:16:56 GMT
Sender: news@athena.mit.edu (News system)
Organization: MIT Center for Space Research
In article <1991Oct28.204829.5717@cs.UAlberta.CA>
martin@space.ualberta.ca (Martin Connors) writes:
>In article <1991Oct28.164548.5539@elroy.jpl.nasa.gov>
>baalke@kelvin.jpl.nasa.gov (Ron Baalke) writes:
>> LARGE SCALE MAPS OF VENUS TO BE RELEASED
>> Large-scale hemispheric maps of Venus will be released at a
>> news conference at NASA Headquarters, Washington, D.C., at 1
>> p.m. EST, Tuesday, Oct. 29. The maps were made from the
>> radar data acquired by the Magellan spacecraft in its first,
>> 8-month long, mapping cycle. The processing of the "cycle 1" data
>> sets, for both imagery and altimetry, was completed recently.
>This perhaps obsoletes my request for Pioneer Venus altimetry digital data
>to help me prepare a reference aid for CDROM users of Magellan data. I had
>no idea the processing of Magellan data was complete to the degree to allow
>such maps to be made. I guess I should now ask if the data forming the bases
>of these maps is available in low-res digital form...
Two types of altimetric Magellan data, processed here at MIT,
will be released in January to complement the 48 CD-ROM radar image
disks. Firstly there will be 10 ARCDR ("altimetry and radiometry
composite data") disks, containing about 1 Kbyte of data on
each of 4 million altimeter "foot-prints", and about 250 bytes of
data on 6 million radiometer "footprints". The footprint size
depends chiefly on spacecraft altitude. Each disk con- tains
C-language source code to read the binary data files on a variety of
UNIX platforms + VAX/VMS. So far, the only higher level software
available for browsing the ARCDR and overlaying the footprints on
side-looking images runs under SunView on Sun SparcStations. It is
called MGMDQE and is the same software we used to prepare the data.
Information on how to order MGMDQE is contained on the disks.
The second type of altimetric data is the GxDR ("global topography,
emissivity, slope, and reflectivity data record"). This fits on a
single GxDR CD-ROM disk, and consists of images of these four
surface data types, derived by resampling the individual ARCDR
footprints and removing certain systematic errors. The pixel size is
about 5x5 kilometers, and each data type is represented by four
different map projections: sinusoidal, Mercator, and north and south
polar stereographic. Like the side-looking image files, GxDRs are in
JPL's VICAR2 format.
Peter Ford
MIT and Magellan Project
|
| 456.410 | Maat Mons volcano may be active | MTWAIN::KLAES | All the Universe, or nothing! | Wed Oct 30 1991 11:27 | 112 |
| Article: 2123
From: clarinews@clarinet.com (WILLIAM HARWOOD, UPI Science Writer)
Newsgroups: clari.tw.science,clari.tw.space
Subject: Global maps of Venus released
Date: 30 Oct 91 00:13:32 GMT
The first global maps of cloud-shrouded Venus were unveiled
Tuesday showing a tortured, hellish planet wracked by enigmatic
geological forces, long-lived impact craters and dozens of volcanoes,
including at least one that might still be erupting.
Based on radar images taken by NASA's remarkably successful
Magellan probe, the six global maps -- two polar views and four
hemispheric shots -- provide more detail about Venus than cartographers
have ever gathered about Earth, three quarters of which is under water.
[Should we orbit a MAGELLAN-type satellite around Earth then? Yes, I
know about SEASAT, but it ceased functioning prematurely in 1978 and
has not been replaced, to my knowledge. - LK]
``Magellan has now collected high resolution radar imagery of
about 92 percent of the surface of (Venus),'' said Wesley Huntress,
director of NASA's solar system exploration division. ``The results
have permitted a new view of the planet that is most like the Earth in
the solar system. [I thought that distinction belonged to Mars? - LK]
``Magellan has really revealed a new Venus globe just as its
namesake, Magellan the [human] explorer, revealed a new planet when he
circumnavigated (Earth).''
At a Washington news conference carried by NASA's satellite
television network, the space agency released a spectacular video
showing Venus slowly rotating in space, the first high-resolution
global view of the second planet from the Sun.
Resembling a bright orange pizza, Venus is girdled by vast
networks of fractures and channels and dotted with a bewildering
variety of volcanoes and steep mountain ranges.
Earth's crust is believed to be made up of continental plates
that ``float'' on a mantle of molten rock. In some areas, such as the
mid-Atlantic Ocean, upwelling material from the interior of the
planet adds to Earth's crust. In other places, plates plunge back into
the interior.
No signs of such ``plate tectonics'' or ``continental drift''
have been conclusively discovered by Magellan on Venus, but scientists
are increasingly confident the planet is geologically active.
John Wood, a Magellan radar investigator with the Smithsonian
Astrophysical Observatory, said an equatorial volcano named Maat Mons
is the best candidate yet for an active volcano on Venus.
Given the chemical makeup of Venus's atmosphere and the
900-degree surface temperature, scientists believe weathering on Venus
-- the chemical alteration of surface material into other minerals --
may proceed at a very rapid rate.
Virtually all of the volcanoes studied so far on Venus show
signs of such weathering, summits covered with highly radar reflecting
minerals that otherwise might not be present. But the summit of Maat
Mons is remarkably non-reflective, indicating the absence of minerals
produced by weathering.
``Why would the business end of the Maat volcano...be radar
dark unlike the other peaks on Venus? If weathering is what produces
the mineral that makes the other peaks radar bright, the most obvious
answer is the summit of Maat Mons has not been weathered,'' Wood said.
``And why wouldn't it have been weathered? Most likely because
it hasn't had time to be weathered; fresh lava has poured out onto the
summit relatively recently.''
How recently? Possibly within the past decade, Wood said.
``The volcano may still be active,'' he said. ``We consider
this structure as the best candidate for finding a currently active
volcano on the surface of Venus.''
Scientists currently are examining new radar images to search
for ``fingers'' of lava or other changes that might have occurred since
Magellan's last pass that could resolve the matter once and for all.
``I don't know if we'll find it or not,'' Wood said. ``In an
average year's span you probably would not see a new flow on the
island of Hawaii. It's really a rather long shot that we're going to
see something this time, but hope springs eternal.''
Magellan, launched from the Shuttle Atlantis on May 4, 1989,
began mapping the planet on Sept. 16, 1990. The first ``cycle'' of
mapping operations ended May 15 after one Venusian ``day'' -- 243
Earth days.
During that period, Magellan mapped most of the planet in
unprecedented detail, using radar beams instead of visible light to
``see'' through the thick clouds that perpetually block the planet's
surface from view.
The resulting data can be processed by computers on Earth to
create photograph-like images of Venus's surface, showing features as
small as 350 feet across -- about the size of a football field -- and
10 times better than the best previous data. The data also can be used
to make dramatic movies.
The spacecraft currently is mapping Venus's south polar region
and filling in gaps that were missed earlier. If all goes well, a
third cycle of observations will be conducted next year to generate
stereo views of the planet.
When all is said and done, Magellan is expected to beam back
enough data to fill some 500,000 library books -- enough to fill a
shelf 10 miles long -- and keep researchers busy for years to come.
|
| 456.411 | Science Briefing notes; how its radar works | MTWAIN::KLAES | All the Universe, or nothing! | Wed Oct 30 1991 11:29 | 436 |
| Article: 17927
From: leech@mahler.cs.unc.edu
Newsgroups: sci.space,sci.astro
Subject: Notes from 10/29 Magellan Science Briefing
Date: 29 Oct 91 19:32:48 GMT
Sender: news@cs.unc.edu
Organization: University Of North Carolina, Chapel Hill
Having an NTSC monitor next to my workstation, I can now watch
NASA Select while "working". Here are notes I typed in from today's
Magellan briefing. Please don't ask me for further details, because I
can't provide them. I do not vouch for the absolute accuracy of this
material, I'm not a stenographer and it was going by pretty quickly.
Jon (leech@cs.unc.edu)
__@/
Notes from Magellan Science Briefing on NASA Select - 10/29/91
Wes Huntress - Division Director, Solar System & Exploration Division
Venus superficially similar to Earth, but "stunningly different".
Magellan good for understanding geological differences from Earth and
verifying theories about why it's different.
Project has completed processing first cycle data. 1/2 mapping
data available on 22 CD-ROMS, remainder by end of year. "Digital
treasure chest."
More than halfway through second cycle; filling in gaps. Looking
at new angles to clarify interpretation. Conducting special tests: 3D
stereo radar imagery. Very successful, plan to cover 70% in 3D stereo
in cycle 3 starting Jan. 15.
Measuring internal structure by mapping gravity field.
Maat Mons lacks radar reflective surface - is it a new structure?
New surface maps from radar altimeter + radio science to study
deep into atmosphere.
Steve Saunders, JPL - Magellan Project Scientist
Cycle 2 mapping south pole - about 3/4 done. Fill in gap at
superior conjunction (about 80% done). On orbit 3000 since starting
mapping.
Global mosaic & projection onto a sphere, looking down from N.
pole. Topography + other properties from altimetry data set. Can see
geologic patterns on a global basis. 6 maps: N/S/4 hemispheres.
Large equatorial fracture system including largest volcanoes -
Matt Mons, Beta Regio - like rift systems on Earth. Totally different
features elsewhere - small scale scarp features like subduction scarps
in W. Pacific - seeing stretching & compression - brittle structure
case -> buckling.
Global look at volcanic features. Prof. Hedd & students @ Brown
Smallest domes to largest shield volcanoes.
Jerry Schwaber (sp?) mapped impact craters - randomly distributed.
[they look to number in low hundreds on slide - Jon] Are we seeing
catastrophically resrufaced Venus (~800 My) or continuing process with
small amounts of vulcanism?
Mapped fracture zones. Map major parts giving only an equatorial
distribution - what's going on? Puzzle. More extensional features in
N/S, compressional in E/W. Another puzzle - would expect them to be
paired.
Landslides - Peter Ford of MIT produced cycle 1/cycle 2 (low
incidence) image. Still somewhat ambiguous; investigators favor radar
layover explanation. (Two possible interpretations for left-looking
data, right looking hard to match up). i) Steep slope, top closer to
radar appears overlapping ii) Actual slumping.
Stereo pair - L sensitive to albedo variation, R to volcanic domes.
Another presentation form - anaglyph - R/B prints (in press
package). Giant trought 800m deep, 10km across.
Channels on plains - intruiging feature. plains are 85% of
surface, history of plains is history of Venus in last few 100 My as
far as we can see. Apparently carved by some sort of fluid lava. Don't
see on Earth, certainly not of this length (100s of kms, longest 800
km). Similar morphology along their entire lengths.
Perspective views to understand relationship of some features -
combine imaging & topography & reproject in computer. Same technique
used for video. Crater farm, Gula Mons (sp?) 3km high. Matt Mons - 9km
high. Recent lava flows pouring over plains. Surface of volcano is not
bright; this is an exception.
Corona Artemis - circular feature 2600km in diameter. Little
relief in interior, margin is trough 150 km across, 3-4 km deep.
Flyaround animation coming. Other chasms to N like Pacific
subductionareas.
Zooming in on trough in next few slides. "Amazingly uniform
feature." Models include mantle plumes rising & spreading, interacting
with external part of crust causing subduction-like patterns.
Computer generated film of radar mapping results - Artemis &
eastern Aphrodite Terra. Simulated color & radarclinometry to enhance
small scale features. Mitchell crater into trough, Diana, Dali chasms.
Ascend for view of Artemis @ end.
Artemis first seen in radar @ Goldstone. Complex topograhy
(arcuate scarps) at margin. 20x vertical exaggeration. One of the most
useful scientific videos for visualizing scientific videos.
John Woods, SAO - Radar Investigator.
Maxwell Montes - highest on Venus. Generally displays very high
reflectivity (observed by Pioneer Venus, confirmed by Magellan).
Appears to require that surface has some special mineral component
which helps reflectivity - opposite of Stealth Bomber. Where would
mineral have come from? Most surface material is not rock; has
weathered into soil (exposed to warm, chemically reactive atmosphere
for 100My forming different minerals). On Earth, turns into clay &
quartz & oxides (soil). On Venus, different kind of soil. Venus is
much hotter at low altitude than on mountaintops (170 degrees F) which
controls composition of minerals in soil. Helps explain different
radar reflectivity behavior. Pyritite (iron sulfide) appears only at
>5km above plains. Electrically conductive mineral -> increase
reflectivity, appears to be responsible to radar bright summits of
high mountaintops.
All except Maat Mons (volcanic peak at E end of Aphrodite Terra,
second highest peak on planet).
Slide of confusing region - Maat Mons + Alpha Regio. Much higher
than surrounding bright region, yet it's dark. Can clearly see
volcanic outflows - no question it's a volcanic edifice, unlike
Maxwell, which is a tectonic structure. Has a radar bright area at low
altitudes; highest are quite radar dark. Why would this be the case?
Hypothesis: Maat Mons has not been weathered. Why not? Hasn't had time
- fresh lava poured out relatively recently. High temp -> very young
(may still be active). Best candidate for currently active volcano.
High priority given to examining second cycle images taken just last
week. Images being processed now.
Gordon Pettengill, MIT - Principal Investigator
First global topography map; contrasted to Pioneer Venus. About
10x resolution, covering further into S and N than PV did.
Distinictive feature - Aphrodite Terra ("Scorpion" for two jaws),
lowest region, Maxwell (W. edge showing rise of 7-8 km with steep
slopes (> 30 degrees) - obvious result of strong tectonic forces).
Maat is ~8km above mean. Can now see true height of such small
volcanic features that weren't resolved by Pioneer. Putting material
into context, allows understanding of interconnections.
Next slide shows global emissivity - related to brightness from
temperature & ability to emit - inverse of reflectivity. A few deep
blue areas (~30% emissivity, corresponding to ~70% reflectivity),
related to Dr. Wood's discussion. Still some S. polar gaps, which will
be filled in.
Special experiment done on Oct. 5 - using telemetry at 2-3 cm
X-Band and 10 cm S-band (normally used for tracking & radar data) to
probe atmosphere (beam bent by atmosphere). At ~32km (20 mi) up,
density gradient so high that curvature of ray matches curvature of
planet - ray is captured! Can get close to this. Advantage compared to
earlier observations is about 10x more sensitivity with Magellan's
large antenna & higher transmited power in X-band - goes several km
lower than previously achieved, and more sensitive to attentuation.
Hope to place levels on sulfuric acid vapor and monitor amount
(indicating amount of volcanic activity). Adds info on vertical
structure and hope to get handle on a different constituent of
atmosphere.
Q&A session:
Plate tectonics controversy?
Saunder: Don't think they've seen features predicted from
pre-Magellan data. Not plate spreading, but subduction & folding.
Probably doesn't go on in quite the same way as on Earth, where plates
are dragged along, but it may be taking up some of the spreading
motions seen at ridges.
Amount of data? Interpretation of radar overlay -> what confidence
in correct interpretation of radar data?
Saunders: 8 orbits of test data analyzed by radar experts &
geologists. Layover almost nonexistent in chosen geometries except in
a few areas, a very small fraction of data set.
Terabits of data - approaching double amount of imaging data.
Better global map of Venus than of the Earth (oceans poorly mapped).
[Q about weathering I didn't catch - Jon]
Wood: Weathering of Maat Mons would proceed in just a few years
(<10). Controversial view. Wouldn't bet a lot on it. Not only
candidate for active volcano, just most prominent - high, stands out.
May be many others that don't come to attention as rapidly.
Can quantify reflectivity vs. other materials?
Gordon: need dielectric of ~80. Only normal candidate is water.
Require unusual mineral, like metallic meterorites.
What are 5-6 most interesting spots for onsite analysis?
Saunders: Alpha Regio, parts of Aphrodite Terra that stand up high
- may be ancient crustal materials formed by differentiation. Finding
feldspar would be interesting. Typical plains area - fundamentally
different from volcanoes, much more extensive, will tell much more
about geochemistry of planet. Pancake volcanoes - steep sided
features. Very dark areas - what are they? Glassy material? Fine
powder? What interaction of surface is going on?
Guess on when we might see landers?
Huntress: Next century. No particular plans to return to Venus in
this decade. Waiting on results of Magellan before deciding what next
step should be. Measure trace elements/isotopic ratios in atmosphere?
Geological sites/geochemistry? Both at once? As we learn more, will
develop ideas on what to do next.
Future Magellan plans?
Gravity data. Measure crust. Models indicate thick crust, but
they're just models.
What has been learned that wouldn't be known 3 years ago?
Saunders: Knew a lot from Pioneer & Venera at 1-2 km resolution.
Now have global picture to 120m resolution. Details of vulcanism &
tectonic features seen fuzzily before. Have focused on details of
processes, know types of volcanoes, can categorize, know there are
impact craters. Confidence in determining relative surface age
globally. Know there are surface wind patterns caused by slow,
sluggish surface winds moving sand and dust around.
What surprises seen in planet as a whole?
Saunders: impact crater morphology - appears very unmodified from
oldest to youngest, for as much as 500-700My or more. Use craters for
determining relative ages of terrains on other bodies. Expected to
find crater aging on Venus, but seems well preserved everywhere.
Will we see new volcanic flows?
Wood: probably not. Timescale too short even for active volcanoes.
Evidence for continuous vs. catastrophic evolution?
We see a random distribution of impact crater. Both sides use same
data. Similar crater morphology, 5-6% at most showing modification
from volcanic activity, 10% by tectonics. Enormous amounts of
modification by plains volcanic activity. Support resurfacing over
large regions continually, OR very large event (duration up to 100My)
covering entire planet, followed by small amounts of modification.
What further evidence to support one or the other?
Sophisticated development of statistical arguments, depending on
detailed geologic arguments & mapping that haven't been done yet. Will
take many scientist & student hours to develop evidence.
Start/stop dates for 1/2/3 mapping cycles?
Saunders:
9/16/90 - start mapping
5/15/91 - end cycle 1
1/15/92 - end cycle 2
cycle 3 will do left-side mapping - similar viewing geometries to
cycle 1. right now in low-shade geometries, don't get as much
mapping time. Will get stereo & quantitative data.
9/15/92 - end that phase. Could lower periapsis to 185 km & do
gravity tracking - would get 360 degrees of tracking
(geophysicists want this).
Health of spacecraft & budget for cycle 3 & beyond?
Saunders: Spacecraft is very healthy, no problems. One tape
recorder lost. Lost exciter for 1 X-Band transmitter. Would not have
redundancy if lost another, would lose radar mapping but not gravity.
One reason to wait for thermally benvolent cycle 3 to do more imaging.
Plenty of hydrazine for any kind of manuever desired. 120 kg
initially, 100 kg left.
Huntress - budgets decided on year-by-year basis. Came out in
fairly good shape for '92. Plan to continue through 3rd cycle. For FY
'93, depends on OMB and Congress.
Status of Pioneer Venus? Doing co-observations?
Pettengill - orbiter will reenter in late '92. Very interested in
revealed variability & height structure of atmosphere - may use drag
to circularize Magellan orbit.
If active volcanoes, will Magellan see it in real time like Voyager?
Saunders: radar gives a snapshot. Image once/8 months and look for
changes - can't see motion directly. Io vulcanism seen in profile
looking at planet limb, radar looks down.
Shape of typical ejecta in terms of dipole length, reflective
characteristics? What is special about Magellan that allowed
discovering Maat Mons?
Wood: Maat Mons is right at equator. Venera didn't go that far
south. Pioneer had too low resolution to see it.
Pettengill - might have seen from Earth-based radar, but geometry
was poor.
Galileo gives indirect evidence for lightning. How does this
correlate with Maat Mons being active?
Saunders: Galileo scientists don't feel there's any correlation.
No link from scientific view.
What would cause rapid weathering?
Wood: weathering is chemical transformation. Igneous rock not in
equilibrium after it cools. Weathering -> change in chemical
character. Erosion -> change in physical character. Speed
exponentially dependent on temperature, Venus is very hot and
atmosphere is reactive (SO2, high water content (~1/10 atm. H20 vapor
pressure)). These tend to accelerate reactions.
What does Magellan say about past existence of oceans on Venus?
Saunders: craters indicate surface is unchanged for as far back as
we can see. Smallest are ~3km -> size of smallest bodies that can get
through thick atmosphere -> suggests atmosphere unchanged for ~800My
with greenhouse at 900 degrees F, disallowing open water.
What is impact of budget pressures on new probes?
Huntress: CRAF survived FY '92 process, but allocated far less
than requested, mandating delay in both CRAF (1 year) and Cassini
(depending on FY '93) 1-2 years, with no effect on Saturn arrival
date. Mars Observer on track for 9/92 launch, has operating budget.
Magellan planned continuing operations. Galileo working on getting
antenna to unfold. CRAF penetrator deleted 1 year ago.
--
Jon Leech (leech@cs.unc.edu) __@/
``You looked so innocent and vulnerable, I wanted to use
everything I knew about radar astronomy to protect you.''
- Dr. Steve Mills in _My Stepmother is an Alien_
Article: 17940
From: pgf@space.mit.edu (Peter G. Ford)
Newsgroups: sci.space,sci.astro
Subject: Re: Stereo radar mapping of Venus
Date: 30 Oct 91 06:36:13 GMT
Sender: news@athena.mit.edu (News system)
Organization: MIT Center for Space Research
In article <1991Oct29.172743.4410@colorado.edu>
privette@boulder.Colorado.EDU (Jeff Privette) writes:
>In article <1991Oct29.013023.7421@unocal.com>, rick@xing.unocal.com
>(Richard Ottolini) writes:
>|> phase inferometry of two nearby passes. The latter is like stereo, but
>|> uses a different part of the signal. It also requires access to a
>|> pre-image part of the radar signal, which aren't as widely available
>|> as the images.
>This sounds interesting -- could someone give a little more detailed
>info on how this technique works (and what information pre-image data
>contains)? Thanks very much.
Unlike optical imaging, radar transmits coherent radiation and detects
the reflected signal with a phase-sensitive receiver so there is
potential information in the phase of the echo, not just in its
magnitude. After initial ground processing, the data is focused into a
2-dimensional image in which each pixel is a complex number
characterizing the echo received from a part of the planetary surface
at a given time delay and frequency shift (i.e. slant range and
azimuth), but, since the planetary surface represented by that pixel
usually contains many wavelength-sized scatterers, the phase is a
random rapidly-varying function of time and antenna location. For the
same reason, the magnitude also contains a large random component--a
phenomenon known as "speckle noise". To reduce the speckle, it is
usual to average together several magnitude images taken in rapid
sequence.
In contrast, interferometric imaging relies on being able to compare
raw complex radar images made by pairs of antennae that are spatially
separated at right angles to the direction of motion. Provided the
antenna separation is small, the phase of a pixel in one image will be
correlated with the phase of the corresponding pixel in the other.
Magellan has only one SAR antenna, but it can use measurements made on
different orbits to simulate a pair of antennae. The orbital tracks
come close enough to each other (no more than a few 100 meters) in
two situations--near the poles on consecutive orbits, and for orbits
separated by exactly 243.02 days--the Venus rotation period.
Having selected a pair of tracks, the two sets of radar data are
processed into pairs of complex images--retaining both amplitude and
phase for each pixel. Then corresponding blocks of pixels in the
images are correlated against one another to estimate the phase
difference for each part of the scene. Provided the orbital paths are
known--from Earth-based tracking--the relative elevation of each pixel
may be derived from the phase differences via some simple trigonometry.
Now for the fun part. Each phase difference is ambiguous since you
can add or subtract 360 degrees from each and get an identical phase
correlation. So you ask a computer to compute the cumulative phase
differences along a series of paths in the 2-dimensional images. The
total phase around each closed path must be zero, and this is usually
sufficient to allow you to figure out where to add and subtract the
360 degree factors.
There are a couple of wrinkles in this technique--first of all, it is
the ultimate CPU hog, and should only be attempted if you have lots of
free CRAY time. Second, Magellan tracking position errors are of the
order of a kilometer, so you may have to process lots of data before
you're lucky enough to find pixels that correlate. Worse than this,
the Magellan radar operates in "bursts"--short groups of pulses
repeated several times a second. To be able to correlate the pixels,
the bursts must be synchronized to a few milliseconds, even though the
orbits may be separated by months or years.
In spite of the formidable technical obstacles, the technique has been
demonstrated on Earth (with spectacular results) by radars carried on
the Shuttle and on high-flying aircraft, so we're hoping that it will
work for Venus during Magellan's extended mission. If it *does*, it
should be capable of determining the relative elevations of some of
Magellan's 120x120 meter image pixels to an accuracy of a few meters
or better. Stick around!
Peter Ford
MIT and Magellan Project
|
| 456.412 | Updates - October 28-31; CDROMs available | MTWAIN::KLAES | All the Universe, or nothing! | Fri Nov 01 1991 13:20 | 146 |
| Article: 17963
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 10/28/91 to 10/30/91
Date: 31 Oct 91 10:01:33 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from Anthony Spear, Magellan Project Manager
MAGELLAN STATUS REPORT
October 28, 1991
The Magellan spacecraft is performing nominally. Starcals (star
calibrations) continue to be very successful, with only two partial
updates over the weekend.
The M1298 command sequence took effect Friday about noon PDT. It
includes two 25-minute cooling periods in each orbit. This sequence
returns to mapping swaths which begin about 5 degrees south of the
equator and extend to the South Pole.
MAGELLAN STATUS REPORT
October 29, 1991
The Magellan spacecraft is performing nominally. Starcals
continue to be very successful.
A new radar command file, was uplinked Monday afternoon. This
file will remain in effect until Friday, November 1st.
MAGELLAN STATUS REPORT
October 30, 1991
The Magellan spacecraft is performing nominally. Starcals
continue to be very successful.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 301-355 Telos | Everything should be as
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | simple as possible, but no
|_____|/ |_|/ |_____|/ | simpler. --Albert Einstein
Article: 17973
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 10/31/91
Date: 1 Nov 91 03:42:48 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from Anthony Spear, Magellan Project Manager
MAGELLAN STATUS REPORT
October 31, 1991
The Magellan spacecraft is performing nominally. All starcals
(star calibrations) yesterday were successful.
The spacecraft is operating under the M1298 command sequence
which includes two 25-minute cooling periods in each orbit. This
results in mapping swaths which begin about 5 degrees south of the
equator and extend to the South Pole.
This morning controllers sent up a command to reset the solar
panel drive mechanism control loss threshhold to 20 degees C.
As of 10:30 AM PST, Magellan has completed its 2913th mapping
orbit of Venus.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 301-355 Telos | Everything should be as
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | simple as possible, but no
|_____|/ |_|/ |_____|/ | simpler. --Albert Einstein
Article: 17969
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro,sci.geo.geology,sci.misc,sci.research
Subject: Magellan/Viking CDROMs Available
Date: 31 Oct 91 23:20:34 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
=====================================
Magellan & Viking Orbiter CD-ROMs
October 31, 1991
=====================================
Sixteen new Magellan CD-ROMs have been released by the Magellan
project. A total of 22 Magellan CD-ROMs has now been released. Also,
two new Viking Orbiter CD-ROMs has been released bringing their total
to 4. The CD-ROMs can be obtained from the National Space Science
Data Center (NSSDC) at the Goddard Space Flight Center.
The "nominal" charge is $20 for the first CD-ROM, and $6 for any
additional CD-ROM in an order. However, NSSDC waives this charge for
bona fide research users, teachers who indicate that they would be
unable to use the material if they were required to pay, government
laboratories, etc. Researchers funded by NASA's Solar System Exploration
Division can also obtain the CD-ROMs through the Planetary Data System
at JPL.
NSSDC's address is:
National Space Science Date Center
Goddard Space Flight Center
Greenbelt, Maryland 20771
Tel: (301) 286-6695
Email address: request@nssdca.gsfc.nasa.gov
You can also reach NSSDC by logging on to their computer. To log
onto the NSSDC computer, telnet to NSSDC.GSFC.NASA.GOV [128.183.36.25]
and give the username "NSSDC". You will then be connected to a menu
system which allows you to use the "Master Directory". You can also
leave questions and orders for the NSSDC staff. If this is the first
time you have used the NSSDC "NODIS" system, it will ask you for
information (name, address, ...) to keep a database of NSSDC users.
NSSDC also provides the following software to display the images:
o IMDISP (IBM PC)
o Browser (Macintosh)
o Pixel Pusher (Macintosh)
o True Color (Macintosh)
The Magellan CD-ROMs are also available via anonymous ftp at
AMES.ARC.NASA.GOV [128.102.18.3]. The Ames site has two CD-ROM drives
and they are accessible through the pub/SPACE/CDROM and pub/SPACE/CDROM2
directories. The CD-ROMs will be rotated on a weekly basis.
The Magellan project is continuing to produce CD-ROMs at the rate
of 8 per month. The current 22 CD-ROMs cover the first 4 months of
mapping, or roughly half of the planet. The full planet will be
available by February in a set of about 50 CD-ROMs.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 301-355 Telos | Everything should be as
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | simple as possible, but no
|_____|/ |_|/ |_____|/ | simpler. --Albert Einstein
|
| 456.413 | Update - November 1 | JVERNE::KLAES | All the Universe, or nothing! | Sun Nov 03 1991 17:52 | 33 |
| Article: 18012
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 11/01/91
Date: 2 Nov 91 11:53:27 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from Anthony Spear, Magellan Project Manager
MAGELLAN STATUS REPORT
November 1, 1991
The Magellan spacecraft is performing nominally. Starcals (star
calibrations) continue to be very successful, with only one missed
star yesterday.
No commanding is planned from today through Monday. The
spacecraft is operating under the M1298 command sequence which
includes two 25-minute cooling periods in each orbit. This results in
mapping swaths which begin about 5 degrees south of the equator and
extend to the South Pole.
As of 10:30 AM PST, Magellan has completed its 2920th mapping
orbit of Venus and is now 70% of the way through Cycle 2.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 301-355 Telos | The two hardest things to
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | handle in life are success
|_____|/ |_|/ |_____|/ | and failure.
|
| 456.414 | Update - November 4 | MTWAIN::KLAES | All the Universe, or nothing! | Tue Nov 05 1991 19:49 | 33 |
| Article: 18031
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 11/4/91
Date: 5 Nov 91 04:06:44 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from Anthony Spear, Magellan Project Manager
MAGELLAN STATUS REPORT
November 4, 1991
The Magellan spacecraft performance is excellent. All systems
are nominal and all starcals (star calibrations) during the weekend
were successful except for two partial updates.
Later today, controllers will send up the weekly "tweak", the
routine update to the radar control parameters.
Magellan is in the second week of operating under a command
sequence M1298 which includes two 25-minute cooling periods. The
spacecraft is presently mapping an area of Venus from just south of
the equator to the South Pole at about 225 degrees longitude which
includes a feature called Imdr Regio.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 301-355 Telos | The two hardest things to
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | handle in life are success
|_____|/ |_|/ |_____|/ | and failure.
|
| 456.415 | Updates - November 5-6 | MTWAIN::KLAES | All the Universe, or nothing! | Thu Nov 07 1991 13:17 | 73 |
| Article: 18081
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 11/05/91
Date: 7 Nov 91 09:09:25 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from Anthony Spear, Magellan Project Manager
MAGELLAN STATUS REPORT
November 5, 1991
The Magellan spacecraft is performing nominally. Magellan is
continuing to map Venus in a right-look mode, covering the area from 5
degrees south of the equator to the South Pole at about 230 degrees
longitude.
Starting early yesterday, controllers noted that the Star Tracker
Unit was failing the self-tests performed on each orbit. After
analysis, it was determined that the present geometry placed the edge
or limb of Venus in the STU field of view during the test causing the
erroneous alarm code.
This condition is expected to continue through the next command
sequence, M1312, which will be unplinked on Thursday, so the
Spacecraft Team has recommended inhibiting the STU self-test for the
next several weeks. Approval of this action is expected at the
Engineering Review Board meeting this morning.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 301-355 Telos | The two hardest things to
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | handle in life are success
|_____|/ |_|/ |_____|/ | and failure.
Article: 18082
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 11/06/91
Date: 7 Nov 91 09:12:33 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from Anthony Spear, Magellan Project Manager
MAGELLAN STATUS REPORT
November 6, 1991
The Magellan spacecraft continues its excellent performance. All
subsystems are nominal, temperatures are in the acceptable range, and
pointing accuracy remains precise.
The Star Tracker Unit (STU) has continued to indicate failed
self-tests on each orbit because the present geometry places the edge
or limb of Venus in the STU field of view during the test. As a
result, the spacecraft switches to the alternate STU and continues its
star calibration maneuver.
This condition is expected to continue for the next several
weeks, so the Spacecraft Team recommended inhibiting the STU self-test
through the next two command sequences. The Engineering Review Board
approved the action yesterday and it will be implemented on the M1312
command upload on Thursday.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 301-355 Telos | The two hardest things to
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | handle in life are success
|_____|/ |_|/ |_____|/ | and failure.
|
| 456.416 | Venus maps and videos | MTWAIN::KLAES | All the Universe, or nothing! | Thu Nov 07 1991 13:18 | 122 |
| Article: 37098
From: fod@elroy.jpl.nasa.gov (Frank O'Donnell)
Newsgroups: sci.space
Subject: Re: Magellan maps and video
Date: 6 Nov 91 22:12:37 GMT
Organization: Jet Propulsion Laboratory
Scott Miller (jsmill01@ulkyvx.bitnet) asks:
> Would it be possible for someone from JPL or NASA to
> tell me if it is possible to get copies of the maps
> and/or video that is mentioned in this news release
> [recent Magellan imagery]?
For the October 29 press conference, two still images and a video were
released. The still images were:
P39224 -- Northern hemisphere of Venus
P39225 -- View of planet centered at equator
The video was titled "Artemis" and is AVC-92-024C1D.
You may also be interested in three still images of Venus that will be
released later this week:
P39380, P39381 -- Views of surface
P39375 -- False color mercator projection of entire planet
The still images can be purchased from Newell Colour in Los Angeles,
telephone (213) 380-2980. The video is available from the Videotape
Company in North Hollywood, (818) 985-1666.
You should wait a few days before inquiring about the pictures to be
released later this week; there is usually a lag of 2 to 3 days before
they are available through the outside supplier.
Frank
fod@elroy.jpl.nasa.gov
Article: 37132
From: yee@trident.arc.nasa.gov (Peter E. Yee)
Newsgroups: sci.space
Subject: Current CD-ROMS on the Ames archives
Date: 7 Nov 91 05:01:19 GMT
Sender: usenet@news.arc.nasa.gov
Organization: NASA Ames Research Center, Moffett Field, CA
I've swapped out the two CD-ROMs being offered for anonymous ftp
access on ames. Current discs are the new Magellan Volume 4, and by
popular request, Voyager Volume 4, which contains Saturn images. The
software found on the CD-ROMs is probably out of date -- Ron Baalke at
JPL has been making some wonderful modifications to IMDISP, and an up-
to-date version can be found on ames, in the pub/SPACE/SOFTWARE directory.
Questions and queries should be sent to me, although since I'll be on
travel through the 19th, I may not be able to answer them immediately.
-Peter Yee
yee@ames.arc.nasa.gov
PS - For those of you who aren't aware of the archive, Ron Baalke and
I maintain a selection of NASA news articles, JPL updates, planetary
probe and manned space images, and other assorted goodies on
ames.arc.nasa.gov. You can access these via anonymous ftp (ftp to
ames, login as user anonymous, use any password (not your own!)) and
then change directory to pub/SPACE. Everything is laid out from there.
Article: 37130
From: HIGGINS@FNAL.BITNET (Bill Higgins-- Beam Jockey)
Newsgroups: sci.space
Subject: Planetary Globes (was RE: SPACE Digest V14 #398)
Date: 7 Nov 91 07:31:00 GMT
Sender: daemon@ucbvax.BERKELEY.EDU
Organization: The Internet
Dale:
>The recent posting about Venus made me wonder about globes of other worlds.
>I've already got a lunar one in my study...
I've asked a few experts about this. If my information is in error,
I'd welcome corrections.
MOON: Not too rare. Replogle makes a lunar globe, and perhaps other
companies do, too. Contact Edmund Scientific, or science-teaching
supply houses.
MARS: There is one globe of Mars available. Sky Publishing sells it
(see full-page ads in *Sky & Telescope*) in the States for US$89.95.
VENUS: Once upon a time, Replogle made a small number of globes of
Mars (from Mariner 9? Viking?) and Venus (from Pioneer Venus
altimetry) for NASA and such outfits. I've seen them at JPL and the
Lunar and Planetary Institute, but they're now unobtainable. My advice
on Venus: Sit tight. When Magellan has completed its third or fourth
pass, say end of 1992, NASA will have a complete high-resolution map
of Venus. Wait another year, and I'm sure somebody will offer a
commercial globe based on it.
PHOBOS: A German company makes a globe of Phobos. Looks like a lump
of coal the size of a watermelon. Costs $500. I don't have details,
but if you're *seriously* interested, I could track them down.
OTHER PLANETS AND SATELLITES: Globes don't exist in any commercial
version. The U.S. Geological Survey has many fine flat maps and
atlases of Mercury, Venus, Mars, and satellites of the gas giants.
Information on them is posted regularly by Jon Leech in the FAQ series
in sci.space/Space Digest and sci.astro. (I realize you know this,
Dale, but I'm gonna post this to the net too.)
I enjoy walking into a store and examining the globes.
"May I help you, sir?"
"Yes, please. Is this the only planet you've got?"
Bill Higgins | "Treat your password like
Fermi National Accelerator Laboratory | your toothbrush. Don't let
Bitnet: HIGGINS@FNALB.BITNET | anybody else use it--
Internet: HIGGINS@FNAL.FNAL.GOV | and get a new one every
43011::HIGGINS | six months." - Cliff Stoll
|
| 456.417 | Updates - November 7-11 | MTWAIN::KLAES | All the Universe, or nothing! | Tue Nov 12 1991 11:26 | 74 |
| Article: 18098
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 11/07/91
Date: 7 Nov 91 23:39:48 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from:
PUBLIC INFORMATION OFFICE
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIF. 91109. TELEPHONE (818) 354-5011
MAGELLAN STATUS REPORT
November 7, 1991
The Magellan spacecraft continues its excellent performance. All
subsystems are nominal, temperatures are in the acceptable range and
pointing accuracy remains precise.
The spacecraft continues mapping in the right-look mode, covering
the area from 5 degrees south of the equator to the south pole.
Earlier this week, controllers noted the star tracker unit was
failing a self-test performed on each orbit. Analysis showed the
present geometry placed the edge, or limb, of Venus in the unit's
field of view during the test. The situation is expected to continue
for the next several weeks, so the Engineering Review Board approved a
plan to discontinue the self-test through the next two command
sequences, beginning today.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 301-355 Telos | The two hardest things to
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | handle in life are success
|_____|/ |_|/ |_____|/ | and failure.
Article: 18125
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 11/11/91
Date: 12 Nov 91 03:17:17 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from Anthony Spear, Magellan Project Manager
MAGELLAN STATUS REPORT
November 11, 1991
The Magellan spacecraft performance is excellent. All systems
are nominal and all starcals (star calibrations) during the weekend
were successful except for four partial updates.
Later today, controllers will send up the weekly "tweak", the
routine update to the radar control parameters.
On Friday, Magellan began execution of command sequence M1312
which includes two 40-minute cooling periods. This has produced some
cooling to portions of the spacecraft. For example, Bay 7 which
contains the CDS (Command Data Subsystem), has cooled from 50 degrees
C to 46.5 degrees C, and the temperature cycle depth has decreased
from 12 degrees C to 7 degrees C.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 301-355 Telos | The two hardest things to
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | handle in life are success
|_____|/ |_|/ |_____|/ | and failure.
|
| 456.418 | Updates - November 7-8 | MTWAIN::KLAES | All the Universe, or nothing! | Wed Nov 13 1991 13:24 | 63 |
| Article: 18172
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 11/07/91
Date: 9 Nov 91 02:58:58 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from Anthony Spear, Magellan Project Manager
MAGELLAN STATUS REPORT
November 7, 1991
The Magellan spacecraft is performing nominally. All starcals (star
calibrations) yesterday were successful.
Today, controllers will send up the M1312 command sequence which
includes two 40-minute cooling periods in each orbit.
As of noon PST, Magellan has completed its 2965th mapping orbit of Venus.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 301-355 Telos | The two hardest things to
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | handle in life are success
|_____|/ |_|/ |_____|/ | and failure.
Article: 18171
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 11/08/91
Date: 9 Nov 91 02:00:46 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from Anthony Spear, Magellan Project Manager
MAGELLAN STATUS REPORT
November 8, 1991
The Magellan spacecraft is performing nominally. Starcals (star
calibrations) continue to be very successful, with only one missed star
yesterday.
No commanding is planned from today through Monday.
The spacecraft will begin operating under the M1312 command
sequence at about 10:45 AM PST today. This sequence includes two
40-minute cooling periods in each orbit, which results in mapping
swaths which begin about 45 degrees south of the equator and extend to
the South Pole.
As of 11:00 AM PST, Magellan has completed its 2972nd mapping
orbit of Venus and is now 73% of the way through Cycle 2.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 301-355 Telos | The two hardest things to
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | handle in life are success
|_____|/ |_|/ |_____|/ | and failure.
|
| 456.419 | Updates - November 12-13 | MTWAIN::KLAES | All the Universe, or nothing! | Fri Nov 15 1991 13:01 | 65 |
| Article: 37315
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space
Subject: Magellan Update - 11/12/91
Date: 14 Nov 91 03:08:04 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
MAGELLAN STATUS REPORT
November 12, 1991
The Magellan spacecraft is performing nominally. Magellan is
continuing to map Venus in a right-look mode, covering the area from
45 degrees south of the equator to the South Pole at about 240 degrees
longitude.
The spacecraft is operating under sequence M1312 which includes
two 40-minute cooling periods. During the cooling periods, the
attitude is biased 20-25 degrees off the sun line to provide added
cooling and reduced temperature cycle depth to Bay 7 which contains
the CDS (Command Data Subsystem).
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 301-355 Telos | The two hardest things to
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | handle in life are success
|_____|/ |_|/ |_____|/ | and failure.
Article: 18224
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 11/13/91
Date: 14 Nov 91 03:10:44 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from Anthony Spear, Magellan Project Manager
MAGELLAN STATUS REPORT
November 13, 1991
The Magellan spacecraft continues its excellent performance. All
subsystems are nominal, temperatures are in the acceptable range, and
pointing accuracy remains precise.
Magellan is continuing to map Venus in a right-look mode,
covering the area from 45 degrees south of the equator to the South
Pole at about 240 degrees longitude.
The spacecraft is operating under sequence M1312 which includes
two 40-minute cooling periods. During the cooling periods, the
attitude is biased 20-25 degrees off the sun line to provide added
cooling and reduced temperature cycle depth to Bay 7 which contains
the CDS (Command Data Subsystem).
As of 2:27 PM PST, Magellan has completed 3010 mapping orbits of Venus.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 301-355 Telos | The two hardest things to
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | handle in life are success
|_____|/ |_|/ |_____|/ | and failure.
|
| 456.420 | Updates - November 14-15 | MTWAIN::KLAES | All the Universe, or nothing! | Mon Nov 18 1991 20:22 | 69 |
| Article: 18316
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 11/14/91
Date: 15 Nov 91 03:33:38 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from Anthony Spear, Magellan Project Manager
MAGELLAN STATUS REPORT
November 14, 1991
The Magellan spacecraft continues its excellent performance. All
subsystems are nominal, temperatures are in the acceptable range, and pointing
accuracy remains precise.
Magellan is continuing to map Venus in a right-look mode, covering the
area from 45 degrees south of the equator to the South Pole at about 240
degrees longitude.
The spacecraft is operating under sequence M1312 which includes two
40-minute cooling periods. During the cooling periods, the attitude is biased
20-25 degrees off the sun line to provide added cooling and reduced temperature
cycle depth to Bay 7 which contains the CDS (Command Data Subsystem).
Commands were successfully uplinked to the S/C to modify the emergency
over temperature fault protection routine to protect DMS-B (Data Management
Subsystem) from potential damage due to high temperatures. A Pseude-Tweak
upload is planned for Thursday, November 14.
As of 10:15 PM PST, Magellan has completed 3016 mapping orbits of Venus.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 301-355 Telos | The two hardest things to
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | handle in life are success
|_____|/ |_|/ |_____|/ | and failure.
Article: 18286
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 11/15/91
Date: 16 Nov 91 02:37:27 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from Anthony Spear, Magellan Project Manager
MAGELLAN STATUS REPORT
November 15, 1991
The Magellan spacecraft continues its excellent performance. All
subsystems are nominal, temperatures are in the acceptable range, and pointing
accuracy remains precise.
The Pseude-Tweak upload was successfully uplinked Thursday, November 14.
It will take effect Friday morning, November 15.
As of 10:15 PM PST, Magellan has completed 3023 mapping orbits of Venus.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 301-355 Telos | The two hardest things to
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | handle in life are success
|_____|/ |_|/ |_____|/ | and failure.
|
| 456.421 | Updates - November 18-20 | MTWAIN::KLAES | All the Universe, or nothing! | Fri Nov 22 1991 15:36 | 127 |
| Article: 18334
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 11/18/91
Date: 21 Nov 91 06:11:30 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from Anthony Spear, Magellan Project Manager
MAGELLAN STATUS REPORT
November 18, 1991
The Magellan spacecraft continues its excellent performance. All
subsystems are nominal, temperatures are in the acceptable range, and
pointing accuracy remains precise. These were only two partial
STARCALS (star calibrations) over the weekend the other 18 being
totally successful.
A Pseude-Tweak upload is planned later today and will become
active on Tuesday, November 19. Note that revised uplink processes
now include a two-week sequence load that is subject to a Pseudo-Tweak
three times on approximately one-half week intervals.
As of 10:15 PM PST, Magellan has completed 3046 mapping orbits of Venus.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 301-355 Telos | The two hardest things to
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | handle in life are success
|_____|/ |_|/ |_____|/ | and failure.
Article: 18342
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 11/19/91
Date: 21 Nov 91 07:13:25 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from Anthony Spear, Magellan Project Manager
MAGELLAN STATUS REPORT
November 19, 1991
The Magellan spacecraft continues its excellent performance. The
star scanner accepted a bad update this morning, and express commands
were uplinked to open up the innovation bounds and disable bias update
processing. The next star scan was successful and express commands
were uplinked to close the innovation bounds back to .07 degrees and
to re-enable bias.
The Traveling Wave Tube Amplifier experienced its nineteenth
Spurious Shut Off (SSO) in flight this morning. Fault Protection
recovery was nominal. No mapping data was lost as the SSO happened
while the spacecraft was off Earth point.
The Pseude-Tweak upload was uplinked on Monday and became active on
Tuesday, November 19.
As of 10:15 PM PST, Magellan has completed 3053 mapping orbits of Venus.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 301-355 Telos | The two hardest things to
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | handle in life are success
|_____|/ |_|/ |_____|/ | and failure.
Article: 18344
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 11/20/91
Date: 21 Nov 91 07:15:01 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from Anthony Spear, Magellan Project Manager
MAGELLAN STATUS REPORT
November 20, 1991
The Magellan spacecraft continues its excellent performance. All
subsystems are nominal, with temperatures within acceptable limits.
As of 10:15 AM PST, Magellan has completed 3061 mapping orbits of Venus.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 301-355 Telos | The two hardest things to
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | handle in life are success
|_____|/ |_|/ |_____|/ | and failure.
Article: 18376
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Re: Magellan Update - 11/18/91
Date: 21 Nov 91 22:15:56 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
In article <2563@mpirbn.mpifr-bonn.mpg.de>,
p515dfi@mpirbn.mpifr-bonn.mpg.de (Daniel Fischer) writes...
>In article <1991Nov21.011159.20866@elroy.jpl.nasa.gov>
>baalke@kelvin.jpl.nasa.gov writes:
>> MAGELLAN STATUS REPORT
>> November 18, 1991
>> A Pseude-Tweak upload is planned later today and will become active on
> ^^^^^^^^^^^^^^
>There's this pseude(o?)-tweak again. WHAT IS IT?
Magellan has its normal sequence load uploaded every two weeks. A
provision was put it to tweak the radar mapping control parameters on
a weekly basis, if necessary. The pseudo-tweak in this case is a
change to some of the parameters in the fault protection to adjust for
thermal changes in the environment around Magellan.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 301-355 Telos | The two hardest things to
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | handle in life are success
|_____|/ |_|/ |_____|/ | and failure.
|
| 456.422 | Updates - November 21-25 | MTWAIN::KLAES | All the Universe, or nothing! | Wed Nov 27 1991 13:43 | 89 |
| Article: 18545
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 11/21/91
Date: 26 Nov 91 06:27:29 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from Anthony Spear, Magellan Project Manager
MAGELLAN STATUS REPORT
November 21, 1991
The Magellan spacecraft continues its excellent performance. All
subsystems are nominal, with temperatures within acceptable limits. Star
scans continue to be very successful.
Today's planned uplink is the M1326 sequence. The sequence, which will
go active on Friday, November 22, continues the two 40 minute hides with
nominal right-looking mapping.
As of 10:15 AM PST, Magellan has completed 3068 mapping orbits of Venus.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 301-355 Telos | The two hardest things to
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | handle in life are success
|_____|/ |_|/ |_____|/ | and failure.
Article: 18546
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 11/22/91
Date: 26 Nov 91 06:30:17 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from Anthony Spear, Magellan Project Manager
MAGELLAN STATUS REPORT
November 22, 1991
The Magellan spacecraft continues its excellent performance. All
subsystems are nominal, with temperatures within acceptable limits.
Star scans continue to be very successful, with only 1 partial update
occuring last night.
The M1326 sequence was successfully uplinked last night and will go
active today at 10:09 AM PST.
As of 10:15 AM PST, Magellan has completed 3076 mapping orbits of Venus.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 301-355 Telos | The two hardest things to
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | handle in life are success
|_____|/ |_|/ |_____|/ | and failure.
Article: 18547
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 11/25/91
Date: 26 Nov 91 05:32:06 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from Anthony Spear, Magellan Project Manager
MAGELLAN STATUS REPORT
November 25, 1991
The Magellan spacecraft performance is excellent. All systems are
nominal and attitude control remains precise.
Later today, controllers will send up the weekly "tweak," the routine
update to the radar control parameters.
On Friday, Magellan began execution of command sequence M1326 which
continues the two 40-minute cooling periods.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 301-355 Telos | The two hardest things to
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | handle in life are success
|_____|/ |_|/ |_____|/ | and failure.
|
| 456.423 | Updates - November 26-27 | MTWAIN::KLAES | All the Universe, or nothing! | Tue Dec 03 1991 12:57 | 69 |
| Article: 18600
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 11/26/91
Date: 28 Nov 91 04:29:08 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from Anthony Spear, Magellan Project Manager
MAGELLAN STATUS REPORT
November 26, 1991
The Magellan spacecraft is performing nominally. Magellan is continuing
to map Venus in a right-look mode, covering the area from 45 degrees south of
the equator to the South Pole at about 250 degrees longitude.
The spacecraft is operating under sequence M1326 which includes two
40-minute cooling periods. During the cooling periods, the attitude is biased
20-25 degrees off the sun line to provide added cooling and reduced temperature
cycle depth to Bay 7 which contains the CDS (Command Data Subsystem). The
biased hide has reduced the CDS temperature about 4 degrees C.
Preparations are being made to reset the Solar Array Drive Mechanism
(SADM) commanded position tomorrow. This will provide margin in the SADM slip
to allow for the long holiday weekend.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 301-355 Telos | The two hardest things to
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | handle in life are success
|_____|/ |_|/ |_____|/ | and failure.
Article: 18603
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 11/27/91
Date: 28 Nov 91 04:34:47 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from Anthony Spear, Magellan Project Manager
MAGELLAN STATUS REPORT
November 27, 1991
The Magellan spacecraft continues its excellent performance. All
subsystems are nominal, temperatures are in the acceptable range, and pointing
accuracy remains precise.
Magellan is continuing to map Venus in a right-look mode, covering the
area from 45 degrees south of the equator to the South Pole at about 260
degrees longitude.
The spacecraft is operating under sequence M1326 which includes two
40-minute cooling periods. During the cooling periods, the attitude is biased
20-25 degrees off the sun line to provide added cooling and reduced temperature
cycle depth to Bay 7 which contains the CDS (Command Data Subsystem).
As of 2:10 PM PST, Magellan has completed 3113 mapping orbits of Venus.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 301-355 Telos | The two hardest things to
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | handle in life are success
|_____|/ |_|/ |_____|/ | and failure.
|
| 456.424 | Update - December 2 | MTWAIN::KLAES | All the Universe, or nothing! | Tue Dec 03 1991 15:35 | 30 |
| Article: 18652
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 12/02/91
Date: 3 Dec 91 03:49:21 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from Anthony Spear, Magellan Project Manager
MAGELLAN STATUS REPORT
December 2, 1991
The Magellan spacecraft performance is excellent. All systems
are nominal and attitude control remains precise. The spacecraft is
presently on orbit #3638 and has completed 3148 radar mapping orbits.
It has finished 82% of its second cycle of Venus.
Later today, controllers will send up the weekly "tweak," the
routine update to the radar control parameters. Magellan continues to
operate under the M1326 command sequence which includes two 40-minute
cooling periods.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3602 Telos | There's no limit to what
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | can be done if it doesn't
|_____|/ |_|/ |_____|/ | matter who gets the credit.
|
| 456.425 | Updates - December 3-6 | MTWAIN::KLAES | All the Universe, or nothing! | Mon Dec 09 1991 18:50 | 166 |
| Article: 18774
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 12/03/91
Date: 8 Dec 91 11:03:56 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from Anthony Spear, Magellan Project Manager
MAGELLAN STATUS REPORT
December 3, 1991
The Magellan spacecraft is performing nominally. Magellan is continuing
to map Venus in a right-look mode, covering the area from 45 degrees south of
the equator to the South Pole at about 270 degrees longitude.
The spacecraft is operating under sequence M1326 which includes two
40-minute cooling periods. During the cooling periods, the attitude is biased
20-25 degrees off the sun line to provide added cooling and reduced temperature
cycle depth to Bay 7 which contains the CDS (Command Data Subsystem).
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3602 Telos | There's no limit to what
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | can be done if it doesn't
|_____|/ |_|/ |_____|/ | matter who gets the credit.
Article: 18776
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 12/04/91
Date: 8 Dec 91 11:08:22 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from:
PUBLIC INFORMATION OFFICE
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIF. 91109. TELEPHONE (818) 354-5011
MAGELLAN STATUS REPORT
December 4, 1991
The Magellan spacecraft continues its excellent performance with
all subsystems normal, temperatures in the acceptable range, and
pointing accuracy remains precise.
Magellan continues to map Venus in a right-look mode, covering
the area from 45 degrees south to the south pole.
Spacecraft controllers have prepared to change the reference
stars used during the star calibration maneuvers on each orbit and
they also will update the solar array drive mechanism commanded position.
Those changes are scheduled for the uplink of the next command
sequence, Thursday, Dec. 5. That sequence will reduce the two cooling
periods per orbit from 40 minutes each to 30 minutes.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3602 Telos | There's no limit to what
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | can be done if it doesn't
|_____|/ |_|/ |_____|/ | matter who gets the credit.
Article: 18777
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update #2 - 12/04/91
Date: 8 Dec 91 11:10:17 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from Anthony Spear, Magellan Project Manager
MAGELLAN STATUS REPORT
December 4, 1991
The Magellan spacecraft continues its excellent performance. All
subsystems are nominal, temperatures are in the acceptable range, and pointing
accuracy remains precise.
Magellan is continuing to map Venus in a right-look mode, covering the
area from 45 degrees south of the equator to the South Pole.
Spacecraft controllers have updated the Kalman gains in preparation for
changing the reference stars used during the star calibration maneuvers on each
orbit. They will also be updating the Solar Array Drive Mechanism commanded
postion.
Most of these changes are in preparation for the uplink of the M1340
command sequence tomorrow. This sequence will reduce the two cooling periods
in each orbit to 30 minutes.
As of 12:23 PM PST, Magellan has completed 3164 mapping orbits of Venus.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3602 Telos | There's no limit to what
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | can be done if it doesn't
|_____|/ |_|/ |_____|/ | matter who gets the credit.
Article: 18779
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 12/05/91
Date: 8 Dec 91 12:14:01 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from Anthony Spear, Magellan Project Manager
MAGELLAN STATUS REPORT
December 5, 1991
The Magellan spacecraft is performing nominally. Magellan is continuing
to map Venus in a right-look mode, covering the area from 45 degrees south of
the equator to the South Pole.
The M1340 command sequence will be uplinked this evening. This sequence
will reduce the two cooling periods in each orbit to 30-minutes.
As of 11:00 AM PST, Magellan has completed 3171 mapping orbits of Venus.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3602 Telos | There's no limit to what
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | can be done if it doesn't
|_____|/ |_|/ |_____|/ | matter who gets the credit.
Article: 18783
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 12/06/91
Date: 8 Dec 91 11:26:46 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from Anthony Spear, Magellan Project Manager
MAGELLAN STATUS REPORT
December 6, 1991
The Magellan spacecraft is performing nominally. The M1340 command
sequence was successfully uplinked Thursday evening. It will go active at
10:00 AM PST. This sequence contains two 30-minute cooling periods per orbit.
The M1340 sequence is a return to left-looking mapping mode. This return
to left-look is to fill in some of the gaps from late in cycle 1 where 2-hide
mapping began.
As of 1:00 PM PST, Magellan has completed 3179 mapping orbits of Venus.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3602 Telos | There's no limit to what
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | can be done if it doesn't
|_____|/ |_|/ |_____|/ | matter who gets the credit.
|
| 456.426 | Updates - December 9-12 | MTWAIN::KLAES | All the Universe, or nothing! | Sat Dec 14 1991 18:38 | 157 |
| Article: 18857
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 12/09/91
Date: 12 Dec 91 07:47:28 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from Anthony Spear, Magellan Project Manager
MAGELLAN STATUS REPORT
December 9, 1991
The Magellan spacecraft is performing nominally. The M1340 sequence,
with two 30-minute cooling periods, is currently active.
On Friday, an extra pseudo-tweak Radar Control Parameter (RCPF) was
uplinked to go active Saturday morning. This extra uplink was needed to take
out some timing errors induced from the previous sequence, M1326.
This afternoon, the next planned pseudo-tweak RCPF, D1344, will be
uplinked.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | There's no limit to what
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | can be done if it doesn't
|_____|/ |_|/ |_____|/ | matter who gets the credit.
Article: 18858
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 12/10/91
Date: 12 Dec 91 06:51:51 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from Anthony Spear, Magellan Project Manager
MAGELLAN STATUS REPORT
December 10, 1991
The Magellan spacecraft is performing nominally. The M1340 sequence,
with two 30-minute cooling periods, is currently active.
On Monday afternoon the pseudo-tweak RCPF (Radar Control Paramater File),
D1344, was successfully uplinked. The RCPF went active this morning.
A non-standard command to change some parameters in the AACS (Attitude
and Articulation Control Subsystem) telemetry support fields was also uplinked
this morning. The parameters changed are to gather gyro net counts at a faster
rate than normal telemetry.
As of 11:00 am PST, Magellan has completed 3208 mapping orbits of Venus.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | There's no limit to what
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | can be done if it doesn't
|_____|/ |_|/ |_____|/ | matter who gets the credit.
Article: 18859
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 12/11/91
Date: 12 Dec 91 07:53:05 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from Anthony Spear, Magellan Project Manager
MAGELLAN STATUS REPORT
December 11, 1991
The Magellan spacecraft is performing nominally. The M1340 sequence,
with two 30-minute cooling periods, is currently active.
Three non-standard commands were uplinked this morning. These commands
updated gyro static fault protection parameters and enabled the gyro static
fault protection.
As of 11:20 am PST, Magellan has completed 3216 mapping orbits of Venus.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | There's no limit to what
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | can be done if it doesn't
|_____|/ |_|/ |_____|/ | matter who gets the credit.
Article: 18884
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 12/12/91
Date: 13 Dec 91 04:45:43 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from:
PUBLIC INFORMATION OFFICE
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIF. 91109. TELEPHONE (818) 354-5011
MAGELLAN STATUS REPORT
December 12, 1991
The Magellan spacecraft is operating normally. The current
sequence contains two 30-minute cooling periods when the spacecraft is
in the shade of the high-gain antenna.
Three non-standard commands were uplinked Wednesday to provide
gyro static fault protection.
Magellan has to date completed more than 3,200 mapping orbits of
Venus and by the end of the year will have mapped more than 93 percent
of the planet. The current mapping cycle ends Jan. 15, 1992.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | There's no limit to what
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | can be done if it doesn't
|_____|/ |_|/ |_____|/ | matter who gets the credit.
Article: 18891
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update #2 - 12/12/91
Date: 13 Dec 91 07:28:59 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from Anthony Spear, Magellan Project Manager
MAGELLAN STATUS REPORT
December 12, 1991
The Magellan spacecraft is performing nominally. The spacecraft is
operating under the M1347 command sequence which includes two 30-minute cooling
periods in each orbit and left-look radar mapping.
At about 10:35 PM PST today, Magellan will perform a four orbit polarimetry
test, then resume normal mapping.
As of noon PST, Magellan has completed its 3223rd mapping orbit of Venus.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | There's no limit to what
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | can be done if it doesn't
|_____|/ |_|/ |_____|/ | matter who gets the credit.
|
| 456.427 | Update - December 13 | MTWAIN::KLAES | All the Universe, or nothing! | Sun Dec 15 1991 12:50 | 31 |
| Article: 18965
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 12/13/91
Date: 15 Dec 91 12:37:51 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from Anthony Spear, Magellan Project Manager
MAGELLAN STATUS REPORT
December 13, 1991
The Magellan spacecraft is performing nominally. The spacecraft
is operating under the M1347 command sequence which includes two
30-minute cooling periods in each orbit and left-look radar mapping.
The four orbit polarimetry test started at 10:35 pm PST Thursday
night and will be completed this morning at 11:35 am PST. This test
rotated the High Gain Antenna during the mapping pass in order to send
and receive the radar signals in the vertical linear polarization plane.
As of 10:45 am, Magellan has completed its 3230rd mapping orbit of Venus.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | There's no limit to what
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | can be done if it doesn't
|_____|/ |_|/ |_____|/ | matter who gets the credit.
|
| 456.428 | MAGELLAN radar image files available | MTWAIN::KLAES | All the Universe, or nothing! | Mon Dec 30 1991 14:43 | 106 |
| Article: 38746
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.geo.geology,alt.cd-rom
Subject: More Magellan Goodies Available
Date: 20 Dec 91 21:22:46 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
MAGELLAN CAPTION FILES
MAGELLAN DATABASE PROGRAM
December 20, 1991
Caption files of the Magellan images and an IBM PC database program that
is a companion program for the Magellan CDROMS are now available.
CAPTION FILES
A complete set of the captions for the Magellan images which have been
publicly released is now available. It can serve as a useful database to
identify P-numbered images of specific features by searching for the
feature name. The caption files are in ASCII format, IBM Wordperfect 5.1
format and a Macintosh Word format compressed with the Stuffit program.
The files are available via anonyous ftp at:
ftp: ames.arc.nasa.gov (128.102.18.3)
user: anonymous
cd: pub/SPACE/MAGELLAN
files: captions.txt (ASCII)
capswp.zip (IBM PC Wordperfect 5.1 -> PKZIP)
caps_txt.sit (Macintosh ASCII -> Stuffit)
caps_word.sit (Macintosh Word -> Stuffit)
HOW TO OBTAIN THE MAGELLAN IMAGES
Each of the caption files reference a P number. Using this P number you
can obtain the Magellan image from:
Newell Color Lab
221 N. Westmoreland Avenue
Los Angeles CA 90064
telephone (213) 380-2980
fax (213) 739-6984
The images can also be obtained from the National Space Science Data
Center (NSSDC). NSSDC's address is:
National Space Science Date Center
Goddard Space Flight Center
Greenbelt, Maryland 20771
Tel: (301) 286-6695
Email address: request@nssdca.gsfc.nasa.gov
Some of the caption files along with their corresponding images are also
available at Ames in VICAR and GIF formats.
ftp: ames.arc.nasa.gov (128.102.18.3)
user: anonymous
cd: pub/SPACE/VICAR
files: *.img (Magellan images in VICAR format)
*.txt (Caption files in ASCII format)
cd pub/SPACE/GIF
files: *.gif (Magellan images in GIF format)
MERGED PROGRAM
An IBM PC database program which is to be used with the Magellan CDROMs
is now available. This program will:
o find the latitude/longitude of named features on Venus; or
o given a latitude/longitude, find the mosaics which lie atop
that point and the CDROMs on which they are found.
The database used by the program is in the RBase format, and the search
logic is readable in the file "merged.app". The two tables in the
database are also found as LOTUS 123 worksheets, in case anyone wishes to
put them into a different database or use them differently.
ftp: ames.arc.nasa.gov (128.102.18.3)
user: anonymous
cd: pub/SPACE/SOFTWARE
file: merged.zip
A Macintosh equivalent program is under development.
HOW TO OTBAIN THE MAGELLAN CDROMs
There are currently 22 Magellan CDROMs available to the public. The
CDROMs may be obtained from the same NSSDC mentioned earlier.
The Magellan CD-ROMs are also available via anonymous ftp at Ames. The
Ames site has two CDROM drives and the CDROMs are rotated on a weekly
basis.
ftp: ames.arc.nasa.gov (128.102.18.3)
user: anonymous
cd: pub/SPACE/CDROM, pub/SPACE/CDROM2
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | There's no limit to what
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | can be done if it doesn't
|_____|/ |_|/ |_____|/ | matter who gets the credit.
|
| 456.429 | Re: .428 | PRAGMA::GRIFFIN | Dave Griffin | Mon Dec 30 1991 18:27 | 4 |
| All available in pragma::public:[nasa.magellan]
- dave
|
| 456.430 | Update - December 27 | MTWAIN::KLAES | All the Universe, or nothing! | Mon Dec 30 1991 18:33 | 48 |
| Article: 28
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space.news
Subject: Magellan Status for 12/27/91 (Forwarded)
Date: 28 Dec 91 00:06:39 GMT
Sender: usenet@news.arc.nasa.gov
Organization: Jet Propulsion Laboratory
[A special thanks to Glenn S. Johnson of JPL for forwarding these
reports while Ron is on vacation. -PEY]
MAGELLAN STATUS REPORT
27 December 1991
1. The Magellan spacecraft is performing nominally. Starcals
continue to be very successful.
2. The spacecraft is operating under the M1354 command
sequence which began on December 20th. This sequence
includes two 30-minute cooling periods in each orbit, and
continues the left-look mapping to fill-in areas missed
near the end of Cycle 1.
3. As of 11:23 AM PST, Magellan has completed 3331 mapping
orbits of Venus and is now 93% of the way through Cycle 2.
Article: 29
From: yee@trident.arc.nasa.gov (Peter E. Yee)
Newsgroups: sci.space.news
Subject: Currently mounted CD-ROMs on the Ames SPACE Archive
Date: 28 Dec 91 01:18:28 GMT
Sender: usenet@news.arc.nasa.gov
Organization: NASA Ames Research Center, Moffett Field, CA
I have mounted two new CD-ROMs on the Ames SPACE Archive. They are
available via anonymous FTP to ames.arc.nasa.gov in the following
directories:
pub/SPACE/CDROM: Magellan, Volume 8
pub/SPACE/CDROM2: Magellan, Volume 9
I will be working through the Magellan discs at a rate of two per week.
After that, I will repeat the Voyager and Viking discs, or put discs on
by demand.
-Peter Yee
yee@ames.arc.nasa.gov
|
| 456.431 | Update - December 30 | MTWAIN::KLAES | All the Universe, or nothing! | Tue Dec 31 1991 11:57 | 32 |
| Article: 33
From: JOHNSON@KELVIN.JPL.NASA.GOV (Glenn S. Johnson)
Newsgroups: sci.space.news
Subject: Magellan Status Report - 12/30/91
Date: 31 Dec 91 04:36:09 GMT
Sender: usenet@news.arc.nasa.gov
Organization: Jet Propulsion Laboratory
Forwarded from Anthony Spear, Magellan Project Manager
MAGELLAN STATUS REPORT
30 December 1991
The Magellan spacecraft performance is excellent. All systems
are nominal and attitude control remains precise.
The spacecraft is presently on orbit #3844 and has completed 3355
radar mapping orbits. It has finished 94% of its second cycle of Venus.
Later today, controllers will send up the weekly "pseudo-tweak,"
the routine update to the radar control parameters.
Magellan continues to operate under the M1354 command sequence which
includes two 30-minute cooling periods and left-look radar mapping to fill
in areas missed during Cycle 1 due to thermal constraints.
********************************************************************
Glenn S. Johnson, NASA's Jet Propulsion Laboratory
Internet: johnson@kelvin.jpl.nasa.gov, gjohnson@coil.cco.caltech.edu
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|
| 456.432 | Updates - December 31 to January 3 | MTWAIN::KLAES | All the Universe, or nothing! | Mon Jan 06 1992 15:31 | 92 |
| Article: 34
From: yee@trident.arc.nasa.gov (Peter E. Yee)
Newsgroups: sci.space.news
Subject: Magallan Status for 12/31/91 (Forwarded)
Date: 31 Dec 91 23:00:12 GMT
Sender: usenet@news.arc.nasa.gov
Organization: NASA Ames Research Center, Moffett Field, CA
PUBLIC INFORMATION OFFICE
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIF. 91109. TELEPHONE (818) 354-5011
MAGELLAN STATUS REPORT
December 31, 1991
The Magellan spacecraft performance is excellent. All systems
are normal and attitude control remains precise.
The spacecraft has completed more than 3,360 mapping orbits
and has finished 94 percent of its second mapping cycle of Venus,
which ends Jan. 15.
Magellan continues to operate under a command sequence which
includes two 30-minute cooling periods and left-look radar
mapping to fill in areas missed during the first cycle due to
thermal constraints.
Article: 39
From: johnson@kelvin.jpl.nasa.gov (Glenn S. Johnson)
Newsgroups: sci.space.news
Subject: Magellan Update - 1/2/92
Date: 4 Jan 92 01:43:38 GMT
Sender: usenet
Organization: Jet Propulsion Laboratory
Forwarded from: Anthony Spear, Magellan Project Manager
MAGELLAN UPDATE
2 January 1992
The Magellan spacecraft is performing nominally.
The spacecraft is operating under the M1354 command sequence which
includes two 30-minute cooling periods in each orbit and left-look radar
mapping.
Tomorrow evening, the M2004 command sequence will be uplinked to the
spacecraft and will begin execution mid-day on Saturday.
As of 1:00 PM PST, Magellan has completed 3378 mapping orbits of
Venus, 1880 orbits in left-look mode and 1498 in right-look mode.
********************************************************************
Glenn S. Johnson, NASA's Jet Propulsion Laboratory
Internet: johnson@kelvin.jpl.nasa.gov, gjohnson@coil.cco.caltech.edu
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SPAN: JPLLSI::GJOHNSON
Article: 40
From: johnson@kelvin.jpl.nasa.gov (Glenn S. Johnson)
Newsgroups: sci.space.news
Subject: Magellan Update - 1/3/92
Date: 4 Jan 92 01:44:10 GMT
Sender: usenet
Organization: Jet Propulsion Laboratory
Forwarded from: Anthony Spear, Magellan Project Manager
MAGELLAN UPDATE
3 January 1991
The Magellan spacecraft is performing nominally. Starcals continue
to be very successful.
The spacecraft is nearing the end of the M1354 command sequence which
began on December 20th. This sequence included two 30-minute cooling periods
in each orbit, and continues the left-look mapping to fill-in areas missed
near the end of Cycle 1.
Late today, controllers will send up the M2004 sequence, which has two
20-minute cooling periods and will continue to the end of Cycle 2 on January
17th with only periodic tweaks.
As of 12:49 PM PST, Magellan has completed 3385 mapping orbits of Venus.
********************************************************************
Glenn S. Johnson, NASA's Jet Propulsion Laboratory
Internet: johnson@kelvin.jpl.nasa.gov, gjohnson@coil.cco.caltech.edu
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|
| 456.433 | | STAR::HUGHES | Captain Slog | Tue Jan 07 1992 14:28 | 6 |
| I heard a news item this morning to the effect that JPL have lost
contact with Magellan. The tone of the item was that Magellan had
already far exceeded its mission goals, suggesting that something
serious is wrong.
gary
|
| 456.434 | Magellan Transmitter Component Fails | PRAGMA::GRIFFIN | Dave Griffin | Tue Jan 07 1992 14:53 | 37 |
| Paula Cleggett-Haleim
Headquarters, Washington, D.C. January 6, 1992
Jim Doyle
Jet Propulsion Laboratory, Pasadena, Calif.
RELEASE: 92-1
After completing 15 months and 3,880 orbits of successfully mapping
over 95 percent of the surface of Venus, the Magellan spacecraft appears to
have suffered a component failure in one of its two downlink transmitters.
This problem has temporarily halted the reception of mapping data.
This loss of mapping data occurred at 7:39 a.m. PST on Saturday, Jan.
4 following a routine star calibration. Engineering data is still being
received, however, and the spacecraft is in good health.
Spacecraft controllers switched to the back-up transmitter turned off
in March 1991, because of degraded performance. The backup transmitter
was operated for 25 minutes and returned good mapping data. As is normal,
the transmitter temperatures rose. At higher temperatures, the backup
transmitter was previously responsible for degraded performance. Near the
end of the test period, signal strength from the back up transmitter showed
some indication of decreasing, a symptom also seen before when the unit
was at higher temperature.
The backup transmitter was turned off and the prime transmitter was
turned back on. Controllers and project officials were meeting Monday to
work out a strategy for use of the backup transmitter for mapping data.
At launch, the primary mission objective was to map 70 percent of the
planet's surface. The Magellan spacecraft completed its prime radar
mapping mission on March 15, 1991. On Jan. 15, 1992, the spacecraft will
have completed its second mapping cycle. Magellan has mapped to date
more than 95 percent of the planet with high-resolution radar. The
transmitter problem does not endanger the gravity mapping objective
planned for later this year.
|
| 456.435 | UPI: NASA's Magellan probe suffers radio problem | PRAGMA::GRIFFIN | Dave Griffin | Tue Jan 07 1992 20:22 | 63 |
| From: clarinews@clarinet.com (WILLIAM HARWOOD, UPI Science Writer)
Newsgroups: clari.tw.space,clari.news.military,clari.news.aviation,clari.news.urgent
Subject: NASA's Magellan probe suffers radio problem
Message-ID: <magellanU2J6505pc@clarinet.com>
Date: 6 Jan 92 22:51:22 GMT
Problems with a critical radio transmitter aboard NASA's remarkably
successful Magellan probe have forced engineers to interrupt the $550
million spacecraft's mapping of cloud-shrouded Venus, officials said
Monday.
The trouble developed Saturday and while the solar-powered spacecraft
is equipped with a backup ``X-band'' transmitter, that unit has a
tendency to overheat, which degrades the quality of the science data
that is beamed back to Earth.
``They appeared to have lost a component on the main downlink
transmitter, that's the X-band,'' said James Doyle, a spokesman for
NASA's Jet Propulsion Laboratory in Pasadena, Calif. ``That stopped
mapping.''
When engineers switched to the backup transmitter, it overheated
after about 25 minutes of operation. Last March, engineers discovered
that the backup radio had a tendency to draw more power than expected,
generating unwanted heat. Since then, Magellan has been using its
primary transmitter to relay data back to Earth.
``The spacecraft is in good health in every other way,'' Doyle said.
``They're going to study this apparently for quite a while. They've got
to find out exactly what happened.''
At least one of the two Motorola-built transmitters -- each one is
believed to have cost at least $1 million -- is required to relay photo-
like radar images of Venus back to Earth. Similar radios are in service
aboard nearly two dozen other spacecraft, according to Magellan builder
Martin Marietta Astronautics Group of Denver.
Doyle said if the primary transmitter cannot be fixed, engineers
would attempt to work around the backup radio's tendency to overheat.
Should both transmitters ultimately prove inoperable, Magellan would be
unable to continue mapping the surface of Venus.
The 2,880-pound Magellan accomplished the primary goal of its mission
last May 15, when it completed a 243-day radar mapping sequence covering
more than 80 percent of the planet's once-hidden surface.
Since then, engineers at the Jet Propulsion Laboratory have been
using the spacecraft to fill in blanks in coverage and to map the
planet's south polar region. As of Saturday, Magellan had mapped more
than 95 percent of Venus during more than 3,880 orbits.
By any standards, the Magellan project repressents one of NASA's most
successful missions, generating a flood of data that has allowed
planetary scientists to create maps of Venus that are more accurate than
those of Earth, where oceans prevent precise seabed mapping.
NASA hopes to operate Magellan for nearly two more years at least,
and while a failure now would deeply disappoint space scientists,
program officials said enough data already has been returned to keep
researchers busy for years to come.
Launched from the shuttle Atlantis on May 4, 1989, Magellan slipped
into orbit around Venus on Aug. 19, 1990. The spacecraft uses radar
beams instead of visible light to ``see'' through the thick clouds that
block the planet's surface from view.
After getting off to a shaky start -- a faulty computer memory knocked
the craft out of contact with Earth several times during initial
operations -- Magellan has been steadily mapping the hidden surface of
Venus, stripping away the veils of mystery that have shrouded Earth's
sister planet since antiquity.
The tortured planet revealed by Magellan's radar imaging system is a
hellish world dotted with giant volcanoes, impact craters, lava flows,
mountain ranges and tremendous fault systems, a violent planet that
appears to be active to this day.
|
| 456.436 | | DECWIN::FISHER | I *hate* questionnaires--Worf | Wed Jan 08 1992 10:54 | 9 |
| Does anyone know if this same transmitter is used to drive the radar itself? I
know that the radar dish is the same one used for the downlink, but how about
the transmitter?
I would assume that if they are careful with the backup transmitter, they can
still fill in some high priority areas (the missing 5% and stuff that they want
to get from a different angle, for example).
Burns
|
| 456.437 | just starting to look at alternatives | ZENDIA::REITH | Jim Reith DTN 226-6102 - LTN2-1/F02 | Wed Jan 08 1992 12:14 | 7 |
| It's also possible that they could tape the mappings and then send it
back in 10 minute bursts to allow the Tx to cool in between
transmissions.
Lots of options still and they did say that is didn't effect the
gravity experiment that was planned for the next phase. Telemetry is
still coming in uninterrupted.
|
| 456.438 | Updates - January 6-8 | MTWAIN::KLAES | All the Universe, or nothing! | Thu Jan 09 1992 13:11 | 104 |
| From: DECWRL::"usenet-space-news-request@ames.arc.nasa.gov" 8-JAN-1992
14:33:55.30
To: sci-space-news@ames.arc.nasa.gov
Subj: Magellan Update - 1/6/92
Forwarded from: Anthony Spear, Magellan Project Manager
MAGELLAN STATUS REPORT
6 January 1991
On Saturday, January 4, the Magellan spacecraft experienced the loss
of X-band subcarrier modulation. At 7:39 AM PST, the Deep Space Net Station
12 at Goldstone (34 meter antenna) was unable to re-establish X-band data
acquisition after the routine star calibration maneuver.
Spacecraft controllers switched to Transmitter B, and after initial
satisfactory performance for about 25 minutes, the controllers switched back
to Transmitter A. There was an degradation of carrier strength near the end
of time on Transmitter B.
Tape Recorder B was turned off (since no science data is being relayed
to Earth) to limit the operating time on the recorder.
So, although Magellan continues to operate under the M2004 command
sequence, no science data is presently being received. Project is meeting
this morning to assess the options for again obtaining science data.
The current scenario is to allow the spacecraft to continue in its
present status through the end of the M2004 sequence and the scheduled battery
reconditioning in the M2014 sequence, then resume radar mapping on January
24th with a modified thermal strategy which keeps the Transmitter B
temperature low enough to avoid the signal degradation.
Another possible scenario is to use a modification of sequence M2004 to
obtain limited science data with Transmitter B before the battery
reconditioning and continue to perform the battery reconditioning sequence
M2017 as planned. Then the following sequence would be revised to begin using
Transmitter B below 30-deg C.
********************************************************************
Glenn S. Johnson, NASA's Jet Propulsion Laboratory
Internet: johnson@kelvin.jpl.nasa.gov, gjohnson@coil.cco.caltech.edu
X.400:(C:USA, ADMD:TELEMAIL, PRMD:NASAMAIL, O:NASA, UN:GSJOHNSON)
SPAN: JPLLSI::GJOHNSON
From: DECWRL::"usenet-space-news-request@ames.arc.nasa.gov" 8-JAN-1992
20:31:37.92
To: sci-space-news@ames.arc.nasa.gov
Subj: Magellan Status for 01/07/92 (Forwarded)
MAGELLAN STATUS REPORT
1. The Magellan mission continues in a state of suspended
science operations, following the malfunction of X-band
Transmitter A on Saturday morning.
2. Late yesterday spacecraft controllers first turned off
the 960 Khz subcarrier, and then the X-band engineering
data to further analyze the performance of Transmitter A.
These additional commands to Transmitter A did not yield
new information. A "tweak" of the command sequence on-
board is being prepared for uplink which will do a
characterization test of Transmitter B on Friday.
3. Several reconfiguration commands are scheduled for uplink
today in preparation for the M2017 command load which
includes the battery reconditioning sequence.
4. All systems other than the transmitters are nominal. DMS-B
is turned off. Temperatures and spacecraft pointing are good.
From: DECWRL::"usenet-space-news-request@ames.arc.nasa.gov" 8-JAN-1992
20:31:44.70
To: sci-space-news@ames.arc.nasa.gov
Subj: Magellan Status for 01/08/92 (Forwarded)
MAGELLAN STATUS REPORT
1. The Magellan mission continues in a state of suspended
science operations, as spacecraft controllers prepare to
test the performance of Transmitter B later today.
2. All systems other than the transmitters are nominal. DMS-B
is turned off. Temperatures and spacecraft pointing are good.
3. A sequence called the "2008 tweak" will be sent to the
spacecraft. Initially Transmitter-A will remain on. Later in
the week Transmitter-B will be turned on. The normal mapping
sequence has been modified so that the transmitter is not
turned off at the end of each playback period.
4. It is hoped that, by allowing the transmitter to reach an
equilibrium temperature (rather than cycling up and down), it
will stabilize so that it can be used operationally.
5. Contingency commands to turn the spacecraft to a hide
position (with the High Gain Antenna to the sun) have been
prepared in the event that the characterization test
threatens the health of the spacecraft.
6. Several reconfiguration commands are being uplinked this
morning in preparation for the M2017 command load which
includes the battery reconditioning sequence.
|
| 456.439 | | DECWIN::FISHER | I *hate* questionnaires--Worf | Thu Jan 09 1992 14:31 | 7 |
| I guess that implies that there are different transmitters used for radar and
downlink. That's good.
It also implies that xmitter A can send a carrier. Hmm. I wonder if there is
some clever way to modulate A's carrier if B totally dies.
Burns
|
| 456.440 | Update - January 9 | MTWAIN::KLAES | All the Universe, or nothing! | Fri Jan 10 1992 18:52 | 74 |
| Article: 65
From: yee@trident.arc.nasa.gov (Peter E. Yee)
Newsgroups: sci.space.news
Subject: Magellan Status for 01/09/92 (Forwarded)
Date: 10 Jan 92 02:23:28 GMT
Sender: usenet
Organization: NASA Ames Research Center, Moffett Field, CA
PUBLIC INFORMATION OFFICE
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIF. 91109. TELEPHONE (818) 354-5011
MAGELLAN STATUS REPORT
January 9, 1992
The Magellan mission continues with science operations
suspended following the failure last weekend of the prime
transmitter. All systems other than the transmitters are normal.
Temperatures and spacecraft pointing are good.
A new sequence was prepared for uplink which will keep
transmitter A on. Later in the week, the backup, transmitter B,
will be turned on and the normal mapping sequence has been
modified so that the transmitter is not turned off at the end of
each playback period.
Spacecraft controllers said they hope that by allowing the
backup transmitter to reach an equilibrium temperature (rather
than cycling up and down), it will stabilize so that it can be
operated normally.
Among commands which will be uplinked in a new command load
will be one for battery reconditioning which was planned earlier.
Article: 66
From: yee@trident.arc.nasa.gov (Peter E. Yee)
Newsgroups: sci.space.news
Subject: Magellan Status for 01/09/92 [#2] (Forwarded)
Date: 10 Jan 92 02:23:40 GMT
Sender: usenet
Organization: NASA Ames Research Center, Moffett Field, CA
1/9/92
MAGELLAN STATUS REPORT
1. The Magellan spacecraft is performing nominally, except for
the X-band transmitters. All starcals yesterday were successful.
2. Yesterday, controllers sent up changes to the launch variable
packet in preparation for the M2017 sequence which includes
the battery reconditioning.
3. They also uplinked the "P2008 Tweak," which includes a
characterization test of Transmitter B later this week. The
test is designed to see if leaving the transmitter on (to
reduce temperature cycling) will lead to a configuration of
the telecommunications system which permits high rate data to
again be relayed to Earth. Transmitter-A has reached a stable
temperature of 45-deg. C with a cycle depth of less than one
degree.
4. The telecommunications engineers are hopeful that, at a more
stable temperature and an alternate subcarrier frequency, the
signal spur which forced them to turn off Transmitter B last
March will be eliminated or reduced.
5. As of 3:00 PM PST today, about 40 orbits of mapping data have
been lost due to the transmitter problem. However, Magellan has
completed 3391 mapping orbits of Venus, 1893 orbits in left-
look mode and 1498 in right-look mode.
|
| 456.441 | Update - January 10 | MTWAIN::KLAES | All the Universe, or nothing! | Sat Jan 11 1992 16:46 | 42 |
| Article: 73
From: yee@trident.arc.nasa.gov (Peter E. Yee)
Newsgroups: sci.space.news
Subject: Magellan Update - 1/10/92
Date: 11 Jan 92 01:47:30 GMT
Sender: usenet
Organization: NASA Ames Research Center, Moffett Field, CA
Forwarded from: Anthony Spear, Magellan Project Manager
MAGELLAN STATUS REPORT
1/10/92
1. This morning, the Magellan spacecraft is performing a
characterization test of Transmitter-B.
2. The test was scheduled to begin at 6:50 AM PST, by commanding
a switch from Transmitter A to B, turning on Tape Recorder
B, and slewing to the beginning of the tape. However, the
uplink was unsuccessful due to a temperature-induced shift in
the receiver frequency.
3. A second uplink attempt at 9:16 AM was successful.
4. Next, telecommunications engineers monitored the rise in
temperature of Transmitter-B to see if it stabilized in the
expected range, and to look for the signal spur. The spur
reappeared as the temperature reached 31.8 degrees C.
5. The characterization test is expected to last through most of
the weekend. The engineers are hopeful that, at a stable
temperature and an alternate subcarrier frequency, the signal
spur which forced them to turn off Transmitter-B last March
will be moved away from the subcarrier, thus allowing radar
mapping to resume.
********************************************************************
Glenn S. Johnson, NASA's Jet Propulsion Laboratory
Internet: johnson@kelvin.jpl.nasa.gov, gjohnson@coil.cco.caltech.edu
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SPAN: JPLLSI::GJOHNSON
|
| 456.442 | Signal spur? | PRAGMA::GRIFFIN | Dave Griffin | Sat Jan 11 1992 18:21 | 5 |
| Would anyone familiar with radio, etc. care to provide a layman's
description of "signal spur"? (It sounds like a sudden amplitude jump/drop
in response to some other aspect of the signal (e.g., frequency or something)).
- dave
|
| 456.443 | | DECWIN::FISHER | I *hate* questionnaires--Worf | Mon Jan 13 1992 14:53 | 7 |
| I don't know the term, but since they said they were hoping it would "move away
from the subcarrier", I would infer that it was some unwanted modulation of the
carrier which was close to the frequency of some subcarrier. If the "spur"
changes frequency to a region where there is no important info, they can filter
it out.
Burns
|
| 456.444 | Update - January 13 | MTWAIN::KLAES | All the Universe, or nothing! | Tue Jan 14 1992 18:33 | 32 |
| From: DECWRL::"usenet-space-news-request@ames.arc.nasa.gov" 13-JAN-1992
20:17:12.81
To: sci-space-news@ames.arc.nasa.gov
Subj: Magellan Update - 01/13/92
Forwarded from Anthony Spear, Magellan Project Manager
MAGELLAN STATUS REPORT
January 13, 1992
The Transmitter B characterization test continued over the weekend. In
the course of the test spacecraft controllers send up 20 non-standard commands.
A configuration which will permit the relay of radar data at 115.2 kbps was
found during the testing.
Presently all systems are nominal and temperatures in the acceptable
range. Transmitter B is at 43 degrees C, with a cycle depth of 0.7 degrees C.
Antenna pointing remains good, with all starcals (star calibrations)
successful.
Controllers are preparing a M2014A command sequence to resume radar
mapping tomorrow. The specific hide times and radar mapping latitudes will be
given in the next status report, but the switch to 115.2 kbps would limit data
to about 42% of the normal radar data collection.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Don't wait for your ship
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | to come in, paddle out to
|_____|/ |_|/ |_____|/ | it.
|
| 456.445 | Update - January 14 | MTWAIN::KLAES | All the Universe, or nothing! | Wed Jan 15 1992 12:53 | 36 |
| From: DECWRL::"usenet-space-news-request@ames.arc.nasa.gov" 14-JAN-1992
19:44:44.78
To: sci-space-news@ames.arc.nasa.gov
Subj: Magellan Update - 01/14/92 (Magellan resumes mapping)
Forwarded from Anthony Spear, Magellan Project Manager
MAGELLAN STATUS REPORT
January 14, 1992
The Magellan spacecraft resumed radar mapping of Venus at 6:23 AM
PST on orbit #3954.
Yesterday and this morning, controllers uplinked the radar
control parameters and a "tweak" of the command sequence. They also
commanded on the 115.2 kbps data rate on the 360 kHz subcarrier, and
switched the S-band engineering telemetry to 40 bps.
The radar data will be relayed from the Deep Space Network
stations to JPL via ground communications, and processed into test
images to see if the radar is affected by the S-band transmitter.
In order to stabilize the temperature of X-band Transmitter B,
both the S and X-band transponders are kept on. The S-band signal is
directed to the medium gain antenna during the radar mapping pass to
reduce interference with the S-band radar beam.
In the present mapping mode, Magellan will perform left-look
scans from about 25 degrees north latitude to 79 degress south.
However, only about 42% of this data will be received on Earth due to
the reduced playback rate.
If all goes well, Magellan will continue mapping until orbit
3976, the end of Cycle 2, at 9:20 AM PST on Friday, leaving a gap of
73.5 orbits to mark the Transmitter anomaly.
|
| 456.446 | Magellan Press Release - Resuming Mapping | PRAGMA::GRIFFIN | Dave Griffin | Wed Jan 15 1992 23:03 | 55 |
| Michael Braukus
Headquarters, Washington, D.C. January 15, 1992
Jim Doyle
Jet Propulsion Laboratory, Pasadena, Calif.
RELEASE: 92-8
The Magellan spacecraft will use its backup transmitter to
resume mapping the surface of Venus with imaging radar on Jan. 24,
following a week of routine battery recharging, project officials at
NASA's Jet Propulsion Laboratory, Pasadena, Calif., said today.
The primary transmitter failed Jan. 4, an official said. The
backup transmitter had been turned off since last March because of a
noise problem which interfered with the mapping data.
Mission Director Doug Griffith said tests over the past several
days, however, have confirmed that mapping data can be received very
well by the backup transmitter using a lower rate to transmit the
data back to Earth.
"One small uncertainty remains with respect to some noise in the
downlink mapping signal," he said. "To account for this, the signal
is being reduced to 115 thousand bits per second, 43 percent of the
normal rate. Despite this uncertainty, we're confident that Magellan
will be operating in a routine mapping mode by the 24th of January."
Project Scientist Steve Saunders said his team was anxious to
resume mapping and planned to gather images from a northern latitudes
area missed during the spacecraft's first cycle because of superior
conjunction, when Earth and Venus were on opposite sides of the sun
and mapping was interrupted.
Magellan's primary mission, to map 70 percent of the planet, was
completed before the end of the first cycle on May 15, 1991. To date
it has mapped more than 95 percent of Venus. The next major target
will be Maxwell Montes, the highest mountain range on Venus.
Magellan today began its third 243-day mapping cycle which will
emphasize stereoscopic mapping. Each mapping cycle represents one
Venus day or 243 Earth days, while the planet rotates beneath
Magellan's orbit. Images taken earlier in the mission can be viewed
along with new images to reveal stereo views of high resolution
topography, Saunders said.
Features can be imaged in stereo by looking at them twice at
angles at least 15 degrees apart. Magellan's imaging radar looks to
the side on each orbit to see the surface. "Stereo imaging, which
produces a three-dimensional picture, increases our ability to
interpret the images many fold," Saunders said.
Magellan is managed by the Jet Propulsion Laboratory for NASA's
Office of Space Science and Applications, Washington, D.C.
|
| 456.447 | Update - January 15; new CD-ROMs | MTWAIN::KLAES | All the Universe, or nothing! | Thu Jan 16 1992 18:57 | 114 |
| Article: 111
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space.news
Subject: Magellan Update #2 - 01/15/92
Date: 16 Jan 92 00:36:35 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from Anthony Spear, Magellan Project Manager
MAGELLAN STATUS REPORT
January 15, 1992
Magellan resumed radar mapping operations yesterday morning and
the data looks good. All systems other than the transmitters are
nominal. Temperatures and antenna pointing are good. Transmitter B
is presently at 45 degrees C.
The present operating mode requires some non-standard commanding
to maintain the telecommunications configuration. Magellan is
presently transmitting radar data at 115.2 kbps on the 360 kHz X-band
subcarrier, and engineering telemetry at 40 bps on S-band.
Last night the spacecraft experienced a spurious shutoff of the
high power amplifier (TWTA SSO). The on-board fault protection
sequence automatically restarted the TWTA, but switched to the 960 kHz
subcarrier. Some radar data was lost due to noise on this subcarrier
and controllers had to send commands reset the proper configuration.
The Radar System Engineering Team reports no apparent
interference or image degradation from having the transmitters on
during the mapping pass.
Magellan is now just 15 orbits from the end of Cycle 2. The
M2017 sequence, which will be uplinked tomorrow and go active on
Friday morning, will suspend mapping for about one week while the
on-board batteries are reconditioned as previously planned.
Cycle 3 radar mapping will begin on January 24, with an emphasis
on obtaining left-look stereoscopic images of the region around
Maxwell Montes.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Don't wait for your ship
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | to come in, paddle out to
|_____|/ |_|/ |_____|/ | it.
From: DECWRL::"usenet-space-news-request@ames.arc.nasa.gov" 16-JAN-1992
16:53:50.98
To: sci-space-news@ames.arc.nasa.gov
Subj: Magellan CD-ROMs
=====================================
MAGELLAN CD-ROMs
January 16, 1992
=====================================
Twenty new Magellan CD-ROMs have been released by the Magellan
project. A total of 42 Magellan CD-ROMs has now been released. The
CD-ROMs contain the radar images taken by the Magellan spacecraft
during its first 8 month mapping cycle of the planet Venus. The
CD-ROMs can be obtained from the National Space Science Data Center
(NSSDC) at the Goddard Space Flight Center.
The "nominal" charge is $20 for the first CD-ROM, and $6 for any
additional CD-ROM in an order. However, NSSDC may waive this charge
for a small amount of data requested by bona fide research users,
government laboratories, etc. School teachers who are unable to pay
may be helped on a case by case basis, and/or as resources permit.
Researchers funded by NASA's Solar System Exploration Division can
also obtain the CD-ROMs through the Planetary Data System at JPL.
NSSDC's address is:
National Space Science Date Center
Goddard Space Flight Center
Greenbelt, Maryland 20771
Tel: (301) 286-6695
Email address: request@nssdca.gsfc.nasa.gov
You can also reach NSSDC by logging on to their computer. To log
onto the NSSDC computer, telnet to NSSDC.GSFC.NASA.GOV [128.183.36.25]
and give the username "NSSDC". You will then be connected to a menu
system which allows you to use the "Master Directory". You can also
leave questions and orders for the NSSDC staff. If this is the first
time you have used the NSSDC "NODIS" system, it will ask you for
information (name, address, ...) to keep a database of NSSDC users.
NSSDC also provides the following software to display the images:
o IMDISP (IBM PC)
o Browser (Macintosh)
o Pixel Pusher (Macintosh)
o True Color (Macintosh)
The Magellan CD-ROMs are also available via anonymous ftp at
AMES.ARC.NASA.GOV [128.102.18.3]. The Ames site has two CD-ROM drives
and they are accessible through the pub/SPACE/CDROM and pub/SPACE/CDROM2
directories. The CD-ROMs will be rotated on a weekly basis.
The Magellan project is continuing to produce CD-ROMs at the rate
of 8 per month. The full planet will be available by February in a
set of about 50 CD-ROMs.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Don't wait for your ship
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | to come in, paddle out to
|_____|/ |_|/ |_____|/ | it.
|
| 456.448 | Update - January 16 | MTWAIN::KLAES | All the Universe, or nothing! | Mon Jan 20 1992 21:26 | 38 |
| Article: 121
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space.news
Subject: Magellan Update - 01/16/92
Date: 17 Jan 92 01:16:56 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from Anthony Spear, Magellan Project Manager
MAGELLAN STATUS REPORT
January 16, 1992
After receiving radar mapping data for about eight orbits, Magellan
controllers decided yesterday to return the radar system to standby mode in
order to further characterize the X-band Transmitter B.
As the temperature of Transmitter B increased from 43 to 45 degrees C,
the signal spur began to affect the 360 kHz subcarrier and it became more
difficult for the DSN (Deep Space Network) stations to lock up on the data.
The Spacecraft team plans to use the remaining time in the present
command sequence to analyze the temperature range in which Transmitter B can
be used successfully.
Later today, they plan to uplink the M2017 sequence which will put
Magellan into a one-week battery reconditioning phase.
Cycle 3 radar mapping will begin on January 24, with an emphasis on
obtaining left-look stereoscopic images of the region around Maxwell Montes.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Don't wait for your ship
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | to come in, paddle out to
|_____|/ |_|/ |_____|/ | it.
|
| 456.449 | Updates - January 17-20 | MTWAIN::KLAES | All the Universe, or nothing! | Wed Jan 22 1992 22:20 | 73 |
| Article: 137
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space.news
Subject: Magellan Update - 01/17/92
Date: 21 Jan 92 00:30:15 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: NASA Ames Research Center, Moffett Field, CA
Forwarded from Anthony Spear, Magellan Project Manager
MAGELLAN STATUS REPORT
January 17, 1992
The Magellan spacecraft is performing nominally as we begin execution of
the M2017 command sequence. All starcals (star calibrations) yesterday were
successful.
The radar sensor is in standby status and will remain so through the next
week as the spacecraft performs a battery reconditioning process. Radar
mapping will resume on January 24th.
Yesterday, controllers uplinked 32 non-standard commands to set the
telecommunications system in various configurations to further characterize the
performance.
The spacecraft also experienced another high power amplifier spurious
shutoff (TWTA SSO), which was corrected by on-board fault correction
procedures.
During the coming week, telecommunication engineers will be analyzing the
results to plan the optimum configuration and temperature contraints for
stereo radar mapping in Cycle 3.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Don't wait for your ship
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | to come in, paddle out to
|_____|/ |_|/ |_____|/ | it.
Article: 141
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space.news
Subject: Magellan Update - 01/20/92
Date: 21 Jan 92 22:26:06 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from Anthony Spear, Magellan Project Manager
MAGELLAN STATUS REPORT
January 20, 1992
Magellan is presently performing a week-long battery reconditioning
process. Radar mapping has been suspended, as planned for this transitional
period between cycles 2 and 3. Presently all systems are nominal and
temperatures in the acceptable range. Engineering telemetry is being received
at 40 bps.
Telecommunications engineers are analyzing the transmitter performance
from the characterization tests last Thursday. They are still confident that a
configuration has been demonstrated which will permit stereo imaging of various
Venus features of special scientific interest during Cycle 3. A transmitter
technical working group is being held on January 21 and 22 in Denver with
results to be presented at a status review on January 23rd.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Don't wait for your ship
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | to come in, paddle out to
|_____|/ |_|/ |_____|/ | it.
|
| 456.450 | MAGELLAN uses VOYAGER spare parts | MTWAIN::KLAES | All the Universe, or nothing! | Tue Jan 28 1992 18:27 | 63 |
| Article: 39612
From: seds%7977@Fedex.Msfc.Nasa.Gov
Newsgroups: sci.space
Subject: JPL Interplanetary Probes
Date: 25 Jan 92 20:49:00 GMT
Sender: st17a@judy.uh.edu (University Space Society)
Organization: University of Houston
In article <8770@ksr.com>, clj@ksr.com (Chris Jones) writes...
>In article <15JAN199215242521@judy.uh.edu>, seds%7977 writes:
>> Look at Magellan. It is a reengineered spare Voyager that was
>>meat for deep space and now is in orbit around Venus. Look at Galialieo (sp).
>>It also is a reengineered Voyager. I am an Engineer.
>
>(Dammit, I'm an ENGINEER, not an historian (or grammarian)).
>
>Magellan uses a Voyager high gain antenna to do its radar mapping and the bulk
>of its earth transmissions. Other than that, I don't think it has much in
>common with the Voyagers (it uses solar panels for power, for example, instead
>of RTGs). If a tire swing can be considered to be a reengineered car, then I
>guess Magellan can be considered to be a reengineered Voyager. (I mean no
>insult to the Magellan project, which I consider to be the most cost-effective
>planetary project ever undertaken by us -- it's just a comment on the
>commonality between the two projects).
Actually there is much more in common than that. The CPU and memory
from Voyager is also used on Magellan. The Voyager "bus" meaning all
of the mechanical and electrical interfaces were used on Magellan, and
from what I remember about reading Magellan design info, are simply
Voyager spares. The Voyager HGA was used because Congress would no
fund the developement costs of the Synthetic Aperature Radar that JPL
wanted to use. This would have given Magellan a 10 meter resolution
compared to its current 110 meter resolution.
The use of the Voyager bus also explains why they are having so many
problems relating to temperature relative to the other operational
satellite in Venusian orbit (Pioneer Venus is there and still
operational since 1978).
>Galileo, I think, also cannot be called a reengineered Voyager. It draws on
>the experience gained with Voyager (and other deep space probes), but it's the
>culmination of (ahem) multiple design and redesign efforts. Galileo is a
>reengineered reengineered Galileo, in my opinion.
Galileo also uses the Voyager bus. The only difference was to increase
the onboard memory and a few other changes that I don't remember. JPL
has not done a new design from the ground up in twenty years. The
Mariner Mark II which is under development now is the first since
then. Correction on that the Mars Observer is also a new design,
optomized for the Martian environs. The Mariner Mark II is however,
JPL's basline for new interplanetary robotic spacecraft.
I would appreciate anyone from JPL either amplifying that or
correcting it. I go to JPL at least once a year to talk to folks there
and my information usually comes from Engineers there who may not know
all of the facts. The info on Magellan however is from the NASA facts
sheet on the project and my reccollections on the funding problems
they had with Congress.
Dennis Wingo UAH
reply to: seds%7977.span@Fedex.Msfc.Nasa.Gov
|
| 456.451 | RE 456.450 | MTWAIN::KLAES | All the Universe, or nothing! | Tue Jan 28 1992 19:40 | 41 |
| Article: 39625
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space
Subject: Re: JPL Interplanetary Probes
Date: 26 Jan 92 09:14:45 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
In article <1992Jan26.005524.30137@uokmax.ecn.uoknor.edu>,
jabishop@uokmax.ecn.uoknor.edu (Jonathan A. Bishop) writes...
>In article <8770@ksr.com>, clj@ksr.com (Chris Jones) writes...
>
>>Magellan uses a Voyager high gain antenna to do its radar mapping and the bulk
>>of its earth transmissions. Other than that, I don't think it has much in
>>commonality between the two projects).
>
>Why was the Voyager HGA used for Magellan rather than the TDRS antenna used
>on Galileo? (Not complaining, mind you :) )
Galileo was to use a new hard structure HGA, but due to the change
from a direct Jupiter trajectory to a VEEGA trajectory, the HGA had to
be folded up for thermal protection while the spacecraft was less than
1 AU from the Sun. Magellan was a scoped down mission, and to help
reduce costs an old Voyager HGA spare was used. This HGA is painted
with a special paint that helps it withstand and reflect the sunlight.
In addition to Voyager's HGA, Magellan also has Voyager's Low Gain
Antenna, Voyager's equipment bus and Voyager's small thruster rockets.
The Medium Gain Antenna was a spare from the Mariner 8/9 spacecraft,
and that's going back 20 years. The main computer (CDS) and the
attitude control computer (AACS) hardware are identical to that used
by Galileo.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Don't wait for your ship
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | to come in, paddle out to
|_____|/ |_|/ |_____|/ | it.
|
| 456.452 | Magellan begins third Venus mapping cycle | PRAGMA::GRIFFIN | Dave Griffin | Tue Jan 28 1992 23:11 | 88 |
| Paula Cleggett-Haleim
Headquarters, Washington, D.C. January 28, 1992
Jim Doyle
Jet Propulsion Laboratory, Pasadena, Calif.
RELEASE: 92-14
The Magellan spacecraft began its third radar mapping
cycle of the surface of Venus on Friday, Jan. 24, and
controllers at NASA's Jet Propulsion Laboratory, Pasadena,
Calif., said today mapping was successful despite earlier
transmitter problems.
The second mapping cycle ended Jan. 15, and controllers
then successfully performed a planned week of battery
recharging.
The spacecraft experienced difficulty with one of its
radio transmitters earlier this month. Mission Director Doug
Griffith reported that the project will now use the backup
transmitter to continue mapping. The backup transmitter was
turned off last year because of a spurious signal that degraded
data transmission back to Earth.
Mapping is now continuing, Griffith said, after a new
operational mode was devised for the backup transmitter which
reduced the data transmission rate from 268,000 to 115,000 bits
per second.
Mission controllers also had to contend with
interference on the spacecraft's radio signal caused by the
spurious signal. That problem is being managed by choosing one
of the two possible data carrier tones to avoid the spurious
signal frequency.
For the first five orbits starting on Jan. 24,
controllers tested various configurations of the data carrier
tones to analyze the spurious signal. Finally, the spurious
signal settled at a frequency which allowed satisfactory radar
data to be transmitted.
The transmitter problem is still under investigation by
a special radio anomaly team that is trying to determine the
most probable failure mechanism in both transmitters and devise
additional methods to optimize use of the backup transmitter.
Now that mapping is continuing, stereo mapping of
selected targets as well as mapping of areas not previously
imaged are underway. The first stereo imaging target is Maxwell
Montes, the highest mountain on Venus.
Additionally, Project Scientist Steve Saunders said a
global survey based on the data acquired during the first two
cycles has found that about 85 percent of the planet is covered
by volcanic rocks, mostly lava flows that form the great plains.
Much of the remaining 15 percent, he said, is high
standing, chaotic material that is faulted and fractured.
"Little can be determined about the composition or nature of the
rocks that form these highlands," he said.
One possible explanation is that the highland rock
represents crustal material that formed soon after the final
accretion of the planet 4.6 billion years ago, Saunders said.
The high, ridged material is seen in the continent- like
terrains such as Aphrodite Terra and Maxwell Montes. "These
regions often appear as islands surrounded by the more recent
lavas that form the volcanic plains," Saunders said.
All of the terrestrial planets appear to have formed
relatively low density crusts, Saunders said. "Little of the
ancient crust remains on Earth because of the constant churning
of plate tectonics." While Venus does not have Earth-like
tectonic plates, it has a long, complex history of deformation
with many episodes of tectonics and faulting.
"The Magellan data will provide the key to understanding
that complex history and perhaps to the understanding of many of
Earth's geologic puzzles," Saunders said.
Magellan already has mapped over 95 percent of Venus.
The primary objective for the Magellan mission called for one
mapping cycle to obtain images of 70 percent of the planet. The
Jet Propulsion Laboratory manages the Magellan Project for
NASA's Office of Space Science and Applications.
|
| 456.453 | Really bad news | CARROL::LEPAGE | Jinky rules!!! | Wed Jan 29 1992 14:22 | 6 |
| I heard on the news this morning that Cycle 3 will be the last one
for Magellan. Because of the lack of funds, Magellan will be shut down
at the end of this mapping cycle.
Drew
|
| 456.454 | Updates - January 22-23 | MTWAIN::KLAES | All the Universe, or nothing! | Wed Jan 29 1992 17:51 | 72 |
| Article: 155
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space.news
Subject: Magellan Update - 01/22/92
Date: 25 Jan 92 22:05:27 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from Tony Spear, Magellan Project Manager
MAGELLAN STATUS REPORT
January 22, 1992
Magellan is presently performing a week-long battery reconditioning
process. Radar mapping has been suspended, as planned for this transitional
period between cycles 2 and 3.
The reconditioning of Battery #1 has been completed. Battery #2 is
presently being discharged offline. It is expected to be recharged and back
online tomorrow.
Presently all systems are nominal and temperatures in the acceptable
range. Starcals (star calibrations) are being performed on every fourth orbit.
Late tomorrow, the M2024 command sequence will be sent to the spacecraft
and radar mapping of Venus, with emphasis on stereo imaging of selected target
area, will resume on Friday afternoon with orbit #4030.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Don't wait for your ship
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | to come in, paddle out to
|_____|/ |_|/ |_____|/ | it.
Article: 168
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space.news
Subject: Magellan Update - 01/23/92
Date: 25 Jan 92 22:45:39 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from Tony Spear, Magellan Project Manager
MAGELLAN STATUS REPORT
January 23, 1992
Magellan continues to perform a week-long battery reconditioning process.
Radar mapping has been suspended, as planned for this week. The
reconditioning of Battery #1 has been completed. Battery #2 is presently
being recharged and will be reconnected to the main spacecraft electical bus
about noon today. All systems are nominal and temperatures in the acceptable
range. Starcals (star calibrations) are being performed on every fourth
orbit.
Late today, the M2024 command sequence will be sent to the spacecraft and
radar mapping of Venus, with emphasis on stereo imaging of selected target
area, will resume on Friday afternoon with orbit #4030.
This weekend, the spacecraft and radar teams will be closely monitoring
the performance of the telecommunications subsystem as mapping is resumed.
The radar mapping data will be relayed directly to JPL via 115 kbps data lines
and will be processed into test images to evaluate the quality.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Don't wait for your ship
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | to come in, paddle out to
|_____|/ |_|/ |_____|/ | it.
|
| 456.455 | Updates - January 24-27 | MTWAIN::KLAES | All the Universe, or nothing! | Thu Jan 30 1992 13:22 | 96 |
| Article: 19940
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 01/24/92
Date: 28 Jan 92 09:24:13 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from the Magellan Project
MAGELLAN STATUS REPORT
January 24, 1992
The Magellan spacecraft battery reconditioning has been completed and
both batteries are back on-line. All systems are nominal and temperatures in
the acceptable range. Starcals (star calibrations) are being performed on
every fourth orbit.
Later today, the M2024 command sequence will begin execution and the
spacecraft will resume radar mapping of Venus. Magellan will first perform a
turn to point its High Gain Antenna at earth, and do a memory readout of the
battery reconditioning events.
The first radar mapping orbit will start at 5:06 PM PST with orbit #4031.
The mapping strategy will include two 20-minute cooling periods in each orbit,
which limits the mapping pass to about 15 minutes. The radar mapping data will
be relayed directly to JPL via 115 kbps data lines and will be processed into
test images to evaluate the quality. This will provide an image swath which
covers an area from 76 degrees to 17.6 degrees north latitude. The
left-looking mapping will provide stereo pairs will images collected during
Cycle 1.
This weekend, the spacecraft and radar teams will be closely monitoring
the performance of the telecommunications subsystem as mapping is resumed.
Non-standard commands have been prepared to change the subcarrier and/or data
rate to minimize the effect of the signal spur in Transmitter B as it shifts in
frequency or amplitude.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Don't wait for your ship
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | to come in, paddle out to
|_____|/ |_|/ |_____|/ | it.
Article: 19947
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 01/27/92
Date: 28 Jan 92 09:27:44 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from the Magellan Project
MAGELLAN STATUS REPORT
January 27, 1992
Late Friday Magellan began execution of the M2024 command sequence which
resumed left-look radar mapping of Venus. As the spacecraft transitioned to
the new sequence, several starcals (star calibrations) were partially
successful. Starcals for the past two days, however, have been successful.
Spacecraft controllers turned off the radio subcarriers to analyze the
signal spur. Initial attempts to relay radar data using the 360 kHz subcarrier
at 115.2 kbps were affected by the spur, so they switched to the 960 kHz
subcarrier and achieved satisfactory results.
The present mode of operation requires that the telecommunications
engineers monitor the frequency of the signal spur and switch subcarriers as
necessary. Non-standard commands have been prepared and tested for this mode.
During the weekend, radar data was relayed from the DSN (Deep Space
Network) stations to JPL via the 115 kbps land lines and processed by the SAR
(Synthetic Aperture Radar) Data Processing Team into test images. Most have
been satisfactory.
The spacecraft team is presently watching the temperatures of critical
subsystems. The CDS (Command Data Subsystem) is now at 55.7 degrees C (with a
normal operating limit of 55 degrees C) and the S-band transmitter is at 47.1
degrees C (desired limit 45 degrees C). Commands to adjust the battery heater
set points may be uplinked to correct this.
The radar mapping strategy includes two 20-minute cooling periods in each
orbit, which limits the mapping pass to about 15 minutes. This will provide
an image swath which covers an area from 76 degrees to 17.6 degrees north
latitude. The left-looking mapping will provide stereo pairs with images
collected during Cycle 1.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Don't wait for your ship
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | to come in, paddle out to
|_____|/ |_|/ |_____|/ | it.
|
| 456.456 | Update - January 29 | VERGA::KLAES | All the Universe, or nothing! | Mon Feb 03 1992 16:22 | 45 |
| Article: 19968
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Magellan Update - 01/29/92
Date: 29 Jan 92 23:24:39 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from the Magellan Project
MAGELLAN STATUS REPORT
January 29, 1992
Magellan continues to map Venus under the M2024 command sequence which
started last Friday. All systems are nominal and pointing accuracy of the
antenna is excellent.
The telecommunications continue to be satisfactory using the 960 kHz
subcarrier at 115.2 kbps. The 115 kbps data rate also permits the radar
science data to be relayed from the DSN (Deep Space Network) stations to JPL
via land lines rather than shipping tapes.
The radar mapping orbits include two 20-minute cooling periods, which
limit the mapping pass to about 15 minutes. This provide an image swath which
covers an area from 76 degrees to 17.6 degrees north latitude. Test image
swaths from the Cycle 3 orbits have been produced and excellent stereo pairs
have been made with Cycle 1 images.
For the next week the focus is on Maxwell Montes, a 36,000 ft high
mountain on Venus, which will be stereo imaged. During Cycle 1, scientists
were amazed by altimeter readings which jumped 7000 meters from one swath to
the next. Altimeter swaths are about 10 km apart. Stereo images of the area
will provide greater precision in plotting the topography.
If indeed Maxwell has such a massive steep slope, it would have important
implications about the age and composition of the surface features, as well as
the internal structures which support such landforms.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Don't wait for your ship
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | to come in, paddle out to
|_____|/ |_|/ |_____|/ | it.
|
| 456.457 | Update - January 31 | VERGA::KLAES | All the Universe, or nothing! | Wed Feb 05 1992 00:25 | 48 |
| Article: 223
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space.news
Subject: Magellan Update - 01/31/92
Date: 1 Feb 92 00:38:27 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from the Magellan Project
MAGELLAN STATUS REPORT
January 31, 1992
1. Magellan continues to map Venus under the M2024 command
sequence which started a week ago. All systems are nominal
and pointing accuracy of the antenna is excellent.
2. The DSN (Deep Space Network) stations continue to receive
satisfactory high rate data using the 360 kHz subcarrier at
115.2 kbps. The 115 kbps data rate also permits the radar
science data to be relayed from the DSN stations to JPL via
land lines.
3. Test images from the Cycle 3 orbits have been produced, and
excellent stereo pairs have been made with Cycle 1 images.
4. The radar mapping swaths covers an area from 76 degrees to 17.6
degrees north latitude. For the next week the focus is on
obtaining stereo images of Maxwell Montes, an 11,000 km high
mountain on Venus.
5. During Cycle 1, scientists were amazed by altimeter readings
which jumped 7000 meters from one swath to the next. Each
altimeter swath is 10 km wide. Stereo images of the area
will provide greater precision in plotting the topography.
6. If indeed Maxwell has such a massive steep slope, it would
have important implications about the age and composition of
the surface features, as well as the internal structures
which support such landforms.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Don't wait for your ship
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | to come in, paddle out to
|_____|/ |_|/ |_____|/ | it.
|
| 456.458 | Latest MAGELLAN radar images | VERGA::KLAES | All the Universe, or nothing! | Wed Feb 05 1992 02:33 | 133 |
| Article: 20075
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro,sci.geo.geology,comp.graphics,sci.misc
Subject: New Magellan Images Available
Date: 2 Feb 92 08:01:36 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
===================
MAGELLAN IMAGES
February 1, 1992
===================
The Magellan project has released three new images taken by the
Magellan spacecraft, and the images are available via anonymous ftp at
the Ames SPACE archives. These new images are in a VICAR format and
have corresponding caption files which describes the images in detail.
I've appended the caption files to the end of this message. Make
sure you are in binary mode when transferring the image files, and in
ASCII mode when transferring the caption files.
ftp: ames.arc.nasa.gov (128.102.18.3)
user: anonymous
cd: pub/SPACE/VICAR
files: split.img (Image of a crater split by a fault)
split.txt (Caption file)
twoticks.img (Image of two "ticks")
twoticks.txt (Caption file)
volctail.img (Volcano with a comet-like tail)
volctail.txt (Caption file)
I've also converted the same images into GIF format in 640x480
resolution with 256 colors.
ftp: ames.arc.nasa.gov (128.102.18.3)
user: anonymous
cd: pub/SPACE/GIF
files: split.gif (Image of a crater split by a fault)
split1.gif (Closeup of the crater)
twoticks.gif (Image of two "ticks")
twotick1.gif (Closeup of the left dome)
twotick2.gif (Closeup of the right dome)
volctail.gif (Volcano with a comet-like tail)
Each of the images are assigned a P number:
split.img P-38741
twoticks.img P-38811
volctail.img P-38810
With this P number you can order the images as lithographs from
one of the following places:
Newell Color Lab
221 N. Westmoreland Avenue
Los Angeles CA 90064
Telephone: (213) 380-2980
Fax: (213) 739-6984
OR
National Space Science Date Center
Goddard Space Flight Center
Greenbelt, Maryland 20771
Telephone: (301) 286-6695
Email address: request@nssdca.gsfc.nasa.gov
The VICAR images can be viewed on an IBM PC computer with the
IMDISP program stored in a zip file called imdisp77.zip, located in
the pub/SPACE/SOFTWARE directory at the same Ames site. IMDISP is the
same program distributed with the Voyager and Magellan CDROMs. Since
I am one of the programmers for IMDISP, I would welcome any feedback
on the program.
Ron Baalke
baalke@kelvin.jpl.nasa.gov
-----------------------------------------------------------------------------
SPLIT.TXT P-38741
This remarkable "half crater" is located in the rift between Rhea and
Theia Montes in Beta Regio. Radar illumination is from the left. The
as yet unnamed crater is 37 (23 miles) kilometers in diameter and is
located at latitude 29.91 degrees north, longitude 282.9 degrees east.
It has been cut by many fractures or faults since it was formed by
the impact of a large asteroid. The eastern half of the crater has
been completely destroyed during the formation of a fault-valley that
is up to 20 kilometers (12 miles) wide and apparently quite deep.
A north-south profile through the very center of this crater is
visible as a result of the downdropping and removal of the eastern
half of the crater. This "profile view" gives a third dimension to
the crater. Thus it will be beneficial to "illuminate" this area from
the opposite side (right-looking) with the Magellan SAR during a later
mapping cycle, permitting an even more detailed view of the geologic
structure of this feature.
-----------------------------------------------------------------------------
TWOTICKS.TXT P-38811
Two unusual volcanic domes are shown in this Magellan full- resolution
mosaicked image. The image covers an area 180 by 240 kilometers (120
by 160 miles) centered at 18.1 degrees north latitude, 303.52 degrees
east longitude, just east of Beta Regio. The dome in the south center
of the image is about 45 kilometers (30 miles) across, with a 20
kilometer (13 mile) caldera, or volcanic collapse crater, in the
center. The dome in the northwest corner of the image is about 30
kilometers (20 miles) across with a small (5 kilometer or 3 mile)
summit crater; the very bright radar return from the western flank of
this dome indicates that it has steep slopes. The flanks of these
volcanoes display prominent gullies which may have been formed by
slumping of surface material or thermal erosion by lava flows.
Variation in the brightness within the surrounding plains show the
extent of lava flows which originated at these volcanoes. Arcuate
fractures surrounding the southern edifice indicate that there has
been subsidence (down-warping) of the dome following eruptive activity.
-----------------------------------------------------------------------------
VOLCTAIL.TXT P-38810
The comet-like tail trending northeast from this volcanic edifice is a
relatively radar-bright deposit. The volcano, whose basal diameter is
5 kilometers (about 3 miles), is a local topographic high that has
slowed down northeast trending winds enough to cause deposition of
this material. The streak is 35 kilometers (about 22 miles) long and
10 kilometers (about 6 miles) wide. The volcano is located at the
western end of Parga Chasma at 9.4 degrees south latitude, 247.5
degrees east longitude.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Don't wait for your ship
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | to come in, paddle out to
|_____|/ |_|/ |_____|/ | it.
|
| 456.459 | | DECWIN::FISHER | I *hate* questionnaires--Worf | Wed Feb 05 1992 15:12 | 9 |
| re .453:
I'm not sure I understand this, but the Feb3 AvWeek indicates that if no more
money is forthcoming, Magellin will shut down after the *4th* cycle, not the 3rd.
Perhaps they are stretching out the money that they do have over the extra time,
even though it crosses a NASA fiscal year?
Burns
|
| 456.460 | Update - February 3 | VERGA::KLAES | All the Universe, or nothing! | Sat Feb 08 1992 18:33 | 41 |
| Article: 249
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space.news
Subject: Magellan Update - 02/03/92
Date: 4 Feb 92 01:16:51 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from the Magellan Project
MAGELLAN STATUS REPORT
February 3, 1992
1. Magellan is into its second week of stereo radar mapping
under the M2024 command sequence. All systems are nominal and
the antenna pointing remains precise.
2. The DSN (Deep Space Network) stations continue to receive
satisfactory high rate data using the 360 kHz subcarrier at
115.2 kbps. The 115 kbps data rate also permits the radar
science data to be relayed from the DSN stations to JPL via
land lines.
3. The radar mapping swaths covers an area from 76 to 17.6
degrees north latitude. This week the focus is on obtaining
stereo images of Maxwell Montes, an 11,000 m high mountain
on Venus.
4. During Cycle 1, scientists were amazed by altimeter readings
which jumped 7000 meters from one swath to the next. Each
altimeter swath is 10 km wide. Stereo images of the area
will provide greater precision in plotting the topography.
The critical orbits for this observation were last Saturday.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Don't wait for your ship
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | to come in, paddle out to
|_____|/ |_|/ |_____|/ | it.
|
| 456.461 | Re: .458 -- images available | PRAGMA::GRIFFIN | Dave Griffin | Mon Feb 10 1992 00:25 | 6 |
| The images mentioned are available in the archives along with the
other Magellan images:
pragma::public:[nasa]mgn_*.gif
- dave
|
| 456.462 | Updates - February 4-6 | VERGA::KLAES | All the Universe, or nothing! | Fri Feb 14 1992 20:14 | 71 |
| Article: 267
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space.news
Subject: Magellan Update - 02/04/92
Date: 5 Feb 92 01:21:44 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from the Magellan Project
MAGELLAN STATUS REPORT
February 4, 1992
1. Magellan continues to map Venus under the M2024 command
sequence. All systems are nominal and all starcals (star
calibrations) yesterday were successful.
2. The DSN (Deep Space Network) stations continue to receive
satisfactory high rate data using the 360 kHz subcarrier
at 115.2 kbps.
3. The radar mapping swaths covers an area from 76 to 17.6
degrees north latitude.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Don't wait for your ship
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | to come in, paddle out to
|_____|/ |_|/ |_____|/ | it.
Article: 295
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space.news
Subject: Magellan Update - 02/06/92
Date: 7 Feb 92 02:51:10 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from the Magellan project.
MAGELLAN STATUS REPORT
February 6, 1992
1. Magellan continues to map Venus under the M2024 command
sequence which started almost two weeks ago. All systems are
nominal and pointing accuracy of the antenna is excellent.
2. The DSN (Deep Space Network) stations continue to receive
satisfactory high rate data using the 360 kHz subcarrier at
115.2 kbps.
3. Today spacecraft controllers plan to uplink an update to the
Solar Array Drive Mechanism commanded position and the M2038
command sequence which will begin execution tomorrow. The
new command sequence will have two 16.5 minute cooling periods.
4. For the next week the focus of the radar mapping is on
obtaining stereo images in eastern Ishtar Terra.
5. A special meeting of the Project Science Group has been
called for next Monday in Washington D.C. to review the
impact of recent NASA budget decisions.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Don't wait for your ship
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | to come in, paddle out to
|_____|/ |_|/ |_____|/ | it.
|
| 456.463 | Update - February 13 | VERGA::KLAES | All the Universe, or nothing! | Sun Feb 16 1992 17:02 | 40 |
| Article: 318
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space.news
Subject: Magellan Update - 02/13/92
Date: 15 Feb 92 01:04:53 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from the Magellan Project
MAGELLAN STATUS REPORT
February 13, 1992
1. Magellan continues to map Venus under the M2038 command
sequence which started last Friday. All systems are nominal
and pointing accuracy of the antenna is excellent.
2. The telecommunications continue to be satisfactory using
the 360 kHz subcarrier at 115.2 kbps.
3. Spacecraft controllers tried switching the transmitter control
units to see if some improvement in communication might
result. However, they forgot that Control Unit A was
configured for 1200 bps telemetry, and the DSN (Deep Space
Network) stations were unable to lock up to the signal.
Telemetry was restored when the telemetry rate was returned
to 40 bps.
4. The radar mapping orbits include two 16.5-minute cooling
periods, and the playback duration is limited by apoapsis
occultation which provides an image swath from 17.5 degrees
north latitude to 18.5 south latitude.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Don't wait for your ship
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | to come in, paddle out to
|_____|/ |_|/ |_____|/ | it.
|
| 456.464 | Updates - February 17-18 | VERGA::KLAES | All the Universe, or nothing! | Fri Feb 21 1992 21:09 | 72 |
| Article: 333
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space.news
Subject: Magellan Update - 02/17/92
Date: 18 Feb 92 06:21:56 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from the Magellan Project
MAGELLAN STATUS REPORT
February 17, 1992
1. The Magellan Project continues to plan for a phase-down which
would provide the necessary carry-over funds for obtaining
gravity data during Cycle 4 (Sept '92 to May '93). Various
options, including early termination of Cycle 3 stereo
imaging, are being discussed.
2. Meanwhile, Magellan continues to map Venus under the M2038
command sequence which started last Friday. All systems are
nominal and the DSN (Deep Space Network) stations continue to
receive satisfactory high rate data using the 360 kHz subcarrier
at 115.2 kbps.
3. Presently the radar image coverage is constrained by the two
16.5 minute cooling periods in each orbit, the reduced
playback rate, and by reduced playback time due to earth
occultation at apoapsis. Each image swath now extends from
17.5 degrees north latitude to 18.5 degrees south.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Don't wait for your ship
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | to come in, paddle out to
|_____|/ |_|/ |_____|/ | it.
Article: 336
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space.news
Subject: Magellan Update - 02/18/92
Date: 19 Feb 92 04:38:05 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from the Magellan Project
MAGELLAN STATUS REPORT
February 18, 1992
1. Magellan continues to map Venus under the M2038 command
sequence. All systems are nominal and all but one of the
starcals (star calibrations) yesterday were successful.
2. The temperatures remain fairly constant, with Bay 7 at 54
degrees C and Transmitter B varying between 48.5 and 49.2 C.
3. The DSN (Deep Space Network) stations continue to receive
satisfactory high rate data using the 360 kHz subcarrier at
115.2 kbs.
4. The radar mapping swaths covers an area from 17.6 degrees
north latitude to 18.5 degrees south.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | In the middle of difficulty
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | lies opportunity --
|_____|/ |_|/ |_____|/ | Albert Einstein
|
| 456.465 | How they map Venus via MAGELLAN | CCA001::KLAES | All the Universe, or nothing! | Tue Feb 25 1992 20:11 | 50 |
| Article: 40759
From: pgf@mgn1.mit.edu (Peter G. Ford)
Newsgroups: sci.space
Subject: Re: Magellan/MO NAV Question
Date: 24 Feb 92 21:01:02 GMT
Sender: news@athena.mit.edu (News system)
Organization: MIT Center for Space Research
In article <29A93564.3D5@deneva.sdd.trw.com>, hangfore@backinblack (John
Stevenson) writes:
> How are the images taken (planned) for Magellan (Mars Orbiter to be)
> registered to the reference globe of their respective planets?
I'll answer this for Magellan. Perhaps someone who is more familiar
with MO geodesy can complete it. Pixel location in Magellan images
depends only on the location and velocity of the spacecraft (its
ephemeris), and on the topography of the planetary surface, not on the
direction in which the antenna is pointing. In a synthetic aperture
radar, the function of the antenna is to concentrate the power and to
reject anomalous echoes, not to focus the individual pixels.
For more than 2 hours out of each 3.25 hour orbit period, Magellan is
transmitting the recorded radar data back to Earth. During this time,
the down-link carrier frequency is carefully recorded and its Doppler
shift, due to line-of-sight motion, is derived. Every 8 orbits or so,
the navigation team computes the spacecraft orbit, using the Doppler
shifts, Keppler's equations, and various perturbation models, e.g.
Venus gravitational inhomogeneities (noted by Pioneer Venus and Venera
orbiters), solar wind pressure and solar gravitational torques. The
resulting ephemerides have been good enough, thus far, that the
individual radar images could be directly transformed to latitude and
longitude and layed down on a "reference globe", whose topography was
derived from radar altimeters flown on the Pioneer Venus and Venera 15
and 16 missions, without noticeable distortion.
As you point out, pixels can be more accurately located if landmark
points are measured in overlapping images. This is being done for
Magellan images by groups at JPL and at the Rand Corp, (a) to better
determine the Venus pole location and spin rate, (b) to generate
better ephemerides, e.g. when Venus is close to the Sun or the axis of
the Magellan orbit is parallel to the line-of-sight from Earth, or (c)
to assist in stereoscopic processing of overlapping images. All three
tie-pointing efforts have been successful, but the technique hasn't
been applied to all possible landmarks because it is very expensive in
human or CPU power.
Peter Ford
MIT and Magellan Project
|
| 456.466 | Updates - February 21-24 | VERGA::KLAES | All the Universe, or nothing! | Thu Feb 27 1992 15:16 | 77 |
| Article: 362
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space.news
Subject: Magellan Update - 02/21/92
Date: 21 Feb 92 22:44:05 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from the Magellan Project
MAGELLAN STATUS REPORT
February 21, 1992
1. Magellan continues to map Venus to provide stereo images of
an equatorial region near Sappho Patera. So far in Cycle 3,
the spacecraft has mapped about 3.5% of the surface
2. All spacecraft systems are nominal and pointing accuracy of
the antenna remains excellent. Transmitter B is peaking at
49.2 degrees C. and Bay 7 (which contains the Command and
Data Subsystem) reaches 52.2 degrees.
3. The DSN (Deep Space Network) stations continue to receive
satisfactory high rate data using the 360 kHz subcarrier at
115.2 kbps.
4. Yesterday, spacecraft controllers uplinked some routine
reconfigurations as well as the M2052 command sequence which
goes active at 10:13 AM PST this morning.
5. Magellan has now completed 3590 mapping orbits of Venus, 202
orbits since the resumption of mapping in Cycle 3.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | In the middle of difficulty
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | lies opportunity --
|_____|/ |_|/ |_____|/ | Albert Einstein
Article: 377
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space.news
Subject: Magellan Update - 02/24/92
Date: 25 Feb 92 01:14:23 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from the Magellan Project
MAGELLAN STATUS REPORT
February 24, 1992
1. Magellan continues to map Venus to provide stereo images of
an equatorial region near Sappho Patera. So far in Cycle 3,
the spacecraft has mapped about 3.5% of the surface
2. All spacecraft systems are nominal and pointing accuracy of
the antenna remains excellent. Only one star was missed
during starcals (star calibrations) over the weekend.
3. Bay 7 (which contains the Command and Data Subsystem) peaked
at 56.7 degrees C during the weekend, but now seems to be cooling.
4. The DSN (Deep Space Network) stations continue to receive satisfactory
high rate data using the 360 kHz subcarrier at 115.2 kbps.
5. Magellan has now completed 3611 mapping orbits of Venus, 225
orbits since the resumption of mapping in Cycle 3.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | In the middle of difficulty
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | lies opportunity --
|_____|/ |_|/ |_____|/ | Albert Einstein
|
| 456.467 | MAGELLAN Venus Images Available | VERGA::KLAES | All the Universe, or nothing! | Thu Feb 27 1992 15:18 | 134 |
| Article: 376
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space.news
Subject: Magellan Images (Macintosh)
Date: 25 Feb 92 00:55:17 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
=============================
MAGELLAN IMAGES (Macintosh)
February 24, 1992
=============================
Two Magellan images are now available that can be displayed on the older
black-and-white Machintoshes. One image if of the pancake volcanos, and the
other is the crater image split by a fault. If the images are placed in the
System folder of the computer and named "StartupScreen", the images will
automatically be displayed when the computer is turned on. The images have
been dithered to replace the grey values with varying densities of black and
white and are stored in the MacBinary format. Obviously, the image quality is
not as good as a grey scale display, but it surprisingly good. The
same images can also be made and displayed as MacPaint files. The images can
be retrieved from the Ames site using anonymous ftp.
ftp: ames.arc.nasa.gov (128.102.18.3)
user: anonymous
cd: pub/SPACE/MAGELLAN
files: pancakes.mac (MacBinary format)
splitcrater.mac (MacBinary format)
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | In the middle of difficulty
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | lies opportunity --
|_____|/ |_|/ |_____|/ | Albert Einstein
Article: 379
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space.news
Subject: Magellan Data Products Available
Date: 25 Feb 92 03:18:40 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
============================
MAGELLAN DATA PRODUCTS
February 24, 1992
============================
NASA's Magellan mission has mapped almost all of the planet Venus using a
high resolution radar instrument. Thousands of images, more than 42 CD-ROMs,
and many other products from Magellan are available to the public from the
National Space Science Data Center (NSSDC) at the Goddard Space Flight Center.
NSSDC is the principal archive and distribution center for all NASA missions.
The following Magellan materials are currently available from NSSDC:
o Fact sheets
o 35 mm slide set (20 slides)
o Lithographed prints of images
o Publicly released (press release) images (10x10 B/W glossies)
o CD-ROMs (standard map mosaic images in digital form)
o Display software for use with the CD-ROMs
o Videotape (1 tape with three animations)
NSSDC's principal charter is to support data distribution to researchers.
Requests from NASA centers, Federal, State, and local governments, and
NASA-funded researchers are supplied without charge. Other requests are
supplied at a nominal charge. NSSDC also has the equipment necessary to
supply special requests, such as photographic enlargements, making viewgraphs
and slides, etc. It has a limited staff able to assist with enquiries about
the products or the identification of products showing a specific feature. It
is not, however, able to support requests for extensive research. NSSDC can
be contacted at:
National Space Science Date Center
Goddard Space Flight Center
Greenbelt, Maryland 20771
Telephone: (301) 286-6695
Email address: request@nssdca.gsfc.nasa.gov
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | In the middle of difficulty
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | lies opportunity --
|_____|/ |_|/ |_____|/ | Albert Einstein
Article: 389
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space.news
Subject: Magellan Caption Files
Date: 26 Feb 92 06:52:38 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
==========================
MAGELLAN CAPTION FILES
February 25, 1992
==========================
A new version of the caption files for the Magellan images is now
available. These caption files are the text that goes along with each of the
public released Magellan images, and gives a detailed description of each
image. The caption files are provided in four formats: ASCII format, IBM
Wordperfect 5.1 format, IBM Word format, and a Macintosh Word format
compressed with the Stuffit program. The files are available via anonymous
ftp at:
ftp: ames.arc.nasa.gov (128.102.18.3)
user: anonymous
cd: pub/SPACE/MAGELLAN
files: captions.txt (ASCII)
caps_wp5.zip (IBM PC Wordperfect 5.1 -> PKZIP)
caps_wrd.zip (IBM PC Word -> PKZIP)
captions.sit (Macintosh Word -> Stuffit)
Each caption is identified by a P number. With this P number you can
order the corresponding image as a lithograph from the National Space Science
Data Center.
National Space Science Data Center
Goddard Space Flight Center
Greenbelt, Maryland 20771
Telephone: (301) 286-6695
Email address: request@nssdca.gsfc.nasa.gov
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | In the middle of difficulty
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | lies opportunity --
|_____|/ |_|/ |_____|/ | Albert Einstein
|
| 456.468 | More MAGELLAN Venus images | VERGA::KLAES | All the Universe, or nothing! | Thu Mar 05 1992 12:05 | 641 |
| Article: 425
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space.news
Subject: Magellan 3D Images
Date: 1 Mar 92 02:49:03 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
====================
MAGELLAN 3D IMAGES
February 29, 1992
====================
The Magellan project has released three new images. These are 3-D
perspective images of the area around Sif and Gula Montes on Venus. The images
were produced at the JPL Multimission Image Processing Laboratory and are
single frames from a video released at the March 5, 1991, JPL news conference.
A color look-up table, 3d.lut, is also included for displaying the images in
false color.
A couple of general comments about the perspective views. First, the
colors are false -- the orange hues were chosen because the attenuated sunlight
at the surface as seen from the Venera landers gives an orange hue to the
Venera images. However, the Magellan images have had color added to liven up
what would be an otherwise drab greytone image. No scientific analysis should
be based on these colors.
Similarly, the sky as seen from Venus's actual surface is also a murky
orange. The sky in these images is black, to contrast against the tones of
the surface. Again, no scientific analysis should be based on the colors in
these scenes.
Finally, all the topography in these scenes has been exaggerated by 22.5
times. That is, vertical differences between features are not in the proper
perspective. Vertical exaggeration is commonly used to emphasize differences
in remote sensing data (e.g., airborne stereographic photo surveys). However,
the viewer of these images would be mistaken to assume that these perspective
views realistically represent what an observer on the surface (or just above
the surface) would see. Please keep in mind that the exaggerations in these
new images are intended to accentuate subtle differences in the topography
and geology of the Venusian surface.
About the specific images:
o eistla.img (P-38724) shows a portion of W. Eistla Regio, with
the viewpoint located 1100 km NE of Gula Mons at an elevation of 7.5
km above the surface. Lava flows extend for 100s of km across
fractured plains shown in the foreground at the base of Gula. Gula
is to the left and Sif is to the right in this image.
o gularif.img (P-39163) has a viewpoint 725 km SE of Gula Mons at an
elevation 1.2 km above the surface. In the foreground, a rift valley
extends to the base of Gula Mons, a 3 km high volcano.
o gulacun.img (P-38720) has a viewpoint 1310 km SW of Gula Mons at
an elevation of 0.78 km. The 48.5 km diameter crater Cunitz sits on
patterned plains. The crater is named for astronomer and
mathematician Maria Cunitz.
The images are available from the Ames SPACE archives using anonymous ftp.
These images are in a VICAR format and are about 1.25 megabytes in size. Each
image has corresponding caption file which provides a detailed description of
the image. Make sure you are in binary mode when transferring the image files,
and in ASCII mode when transferring the caption files.
ftp: ames.arc.nasa.gov (128.102.18.3)
user: anonymous
cd: pub/SPACE/VICAR
files: eistla.img (3D view of Gula Mons & Sif Mons)
eistla.txt (Caption file)
gularif.img (3D view of a rift valley)
gularif.txt (Caption file)
gulacun.img (3D view of Cunitz Crater)
gulacun.txt (Caption file)
3d.lut (Color palette)
I've also converted the same images into GIF format in 640x480 resolution
with 256 colors.
ftp: ames.arc.nasa.gov (128.102.18.3)
user: anonymous
cd: pub/SPACE/GIF
files: eistla.gif (3D view of Gula Mons & Sif Mons)
gularif.gif (3D view of a rift valley)
gulacun.gif (3D view of Cunitz Crater)
Note that each of these images are assigned a P number. With this P
number you can order the images as lithographs from one of the following
places:
Newell Color Lab
221 N. Westmoreland Avenue
Los Angeles CA 90064
Telephone: (213) 380-2980
Fax: (213) 739-6984
OR
National Space Science Data Center
Goddard Space Flight Center
Greenbelt, Maryland 20771
Telephone: (301) 286-6695
Email address: request@nssdca.gsfc.nasa.gov
NSSDC can also supply display software to view the images as well as the
video that the images came from.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | In the middle of difficulty
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | lies opportunity --
|_____|/ |_|/ |_____|/ | Albert Einstein
Article: 413
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space.news
Subject: Magellan Public Release Images
Date: 28 Feb 92 06:40:29 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
===================================
Magellan Public Released Images
February 27, 1992
===================================
Appended to the end of this message are two lists that show all the
Magellan images released to the press, copies of which are available to the
public through the National Space Science Data Center (NSSDC) and through
JPL's Public Information Office contractor, Newell. The "P-HQ" list shows all
the released image P-numbers and the corresponding NASA Headquarters
photographic library black-and-white and color identification numbers. The
"HQ-P" list inverts the sort to show only those images in the NASA HQ library.
These lists correspond to the new Magellan caption files recently distributed.
NASA Headquarters maintains a library of publicly released images from
all NASA programs, including Magellan. Requests from the press or requests
from publishers or authors preparing books for print can be provided without
charge as 4x5 inch positive color or black and white transparencies. Requests
for other formats or requests from other members of the public may be supplied
at nominal cost. Visitors can browse through the collection to select images.
Requests by mail or telephone for assistance in obtaining images can be
supported to a limited extent.
National Space Science Data Center
Goddard Space Flight Center
Greenbelt, Maryland 20771
Telephone: (301) 286-6695
Email: request@nssdca.gsfc.nasa.gov
Newell Colour
221 North Westmoreland Avenue
Los Angeles, California 90064
Telephone: (213) 380-2980
NASA Headquarters
Photographic Library
Code PMD
Washington, DC 20546
Telephone: (202) 453-8375
-------------------------------------------------------------------
This is a list of the P-numbers for all the released Magellan images
and the corresponding NASA Headquarters photographic library numbers.
It can serve both to check which images have been released and to
request materials from HQ for publication uses. It corresponds with
the captions files recently placed in the pub/SPACE/MAGELLAN directory
at ames.arc.nasa.gov.
P-NUMBER HQ-B&W HQ-COLOR
36521 90-H-544
36522 90-H-545
36523 90-H-546
36529
36530
36531
36532
36533
36545 90-H-553
36546 90-H-554
36547 90-H-590
36548 90-H-591
36611 90-H-613
36612 90-H-614
36613 90-H-615
36642 90-H-630
36643 90-H-632
36644 90-H-631
36655
36656
36657
36658
36697 90-H-633
36698 90-H-634
36699 90-H-635
36700
36701
36702
36703
36704
36705
36706
36707
36708
36709
36710
36711 90-H-636
36735
36837
36838
36850
36908 91-H-147
36909
37047
37125 90-H-748
37128 91-H-146
37129
37130
37131
37132
37135
37137 90-H-753 90-HC-680
37138 90-H-749
37139 90-H-750
37140 90-H-751
37141 90-H-752
37236 90-H-784
37264 90-H-783
37265 90-H-782
37266 90-H-781
37296 91-H-145
37322 91-H-59
37342 90-H-827 90-HC-740
37375 ***
37431 91-H-47 91-HC-47
37484 91-H-62 91-HC-57
37492 91-H-60
37493 91-H-61
37500 91-H-65
37501 91-H-64
37554 91-H-81
37598 91-H-100
37599 91-H-129
37600 ***
37601 91-H-130
37651 91-H-134
37706 91-H-131
37707 91-H-132
37708 91-H-133
37786 91-H-135
37787 91-H-136
37788 91-H-137
37789 91-H-138
37824 91-H-175
37831 91-H-176
37944 91-H-181
37945 91-H-346
37946 91-H-182
37947 91-H-183
37948 91-H-184
38054 91-H-254
38055 91-H-251
38056 91-H-252
38088 91-H-340
38089 91-H-341
38098 91-H-253 91-HC-222
38101 91-H-342
38102 91-H-343
38103 91-H-344
38104 91-H-345
38139 91-H-296
38140 91-H-297
38141 91-H-298
38142 91-H-299
38143 91-H-300
38156 91-H-390
38160 91-H-301
38169 91-H-347
38170 91-H-521
38171 91-H-348
38172 91-H-349
38173 91-H-350
38177 91-H-302
38197 91-H-351
38218 91-H-352 91-HC-301
38269 91-H-522
38281 91-H-507
38283 91-H-508
38284 91-H-509
38285 91-H-510
38286 91-H-511
38287 91-H-512
38288 91-H-513
38290 91-H-514
38291 91-H-515
38292 91-H-618
38293 91-H-592
38294 91-H-630
38295 91-H-619
38296 91-H-620
38297 91-H-516
38298 91-H-517
38299 91-H-593
38300 91-H-598
38301 91-H-599
38302 91-H-594
38303 91-H-600
38304 91-H-621
38335 91-H-523
38338 91-H-391
38339 91-H-392
38340 91-H-393
38341 91-H-394
38346 91-H-845 91-HC-745
38359 91-H-444 91-HC-387
38360 91-H-445 91-HC-388
38387 91-H-524
38388 91-H-525
38434 91-H-518
38449 91-H-504 91-HC-441
38450 91-H-505 91-HC-442
38451 91-H-506 91-HC-443
38452 91-H-519
38471 91-H-520
38515 91-H-595
38548 91-H-596
38605 91-H-631
38606 91-H-632
38607 91-H-633
38608 91-H-634
38609 91-H-635
38610 91-H-636
38611 91-H-601
38665 91-H-622
38690 91-H-637
38691 91-H-638
38707 91-H-639
38720 91-H-798 91-HC-702
38721 91-H-801 91-HC-705
38722 91-H-793 91-HC-699
38723 91-H-794 91-HC-700
38724 91-H-809 91-HC-710
38741 91-H-640
38809 91-H-641
38810 91-H-642
38811 91-H-643
38827 91-H-648
38828 91-H-649
38850 91-H-748
38851 91-H-683
38852 91-H-729 91-HC-628
38853 91-H-730 91-HC-629
38856 91-H-681
38857 91-H-680
38870 91-H-682 91-HC-585
38889 91-H-684
38890 91-H-685
38975 91-H-716
39065 91-H-746
39066 91-H-747
39092 91-H-836 91-HC-736
39093 91-H-837 91-HC-737
39144 91-H-792 91-HC-698
39145 91-H-791 91-HC-697
39146 91-H-805 91-HC-709
39147 91-H-807
39163 92-H-31 92-HC-28
39164 91-H-838 91-HC-738
39165 91-H-839 91-HC-739
39166 91-H-840 91-HC-740
39167 92-H-32 92-HC-29
39168 92-H-33 92-HC-30
39175 91-H-795
39191 91-H-796
39194 91-H-802 91-HC-706
39195 91-H-800 91-HC-704
39196 91-H-804 91-HC-708
39224 91-H-799 91-HC-703
39225 91-H-797 91-HC-701
39226 91-H-806
39230 91-H-808
39326 91-H-803 91-HC-707
39342 91-H-869
39374 91-H-841 91-HC-741
39375 91-H-842 91-HC-742
39380 91-H-843 91-HC-743
39381 91-H-844 91-HC-744
39570 92-H-34 92-HC-31
39571 92-H-35 92-HC-32
39572 92-H-36 92-HC-33
39573 92-H-37 92-HC-34
39631 92-H-81
39632 92-H-82
39633 92-H-83
39634 92-H-84
39635 92-H-85
39636 92-H-86
39657 92-H-41 92-HC-38
39658 92-H-42 92-HC-39
39659 92-H-40 92-HC-37
39715 92-H-78 92-HC-71
39716 92-H-79
39717 92-H-80
--------------------------------------------------------------------
This is a list of all the released Magellan images currently at the
NASA Headquarters photographic library and their corresponding
black and white, color, and P-number identifications. It is smaller
than the list of released images, since it excludes the early AV
images which were not placed in the HQ library.
HQ-B&W HQ-COLOR P-NUMBER
90-H-544 36521
90-H-545 36522
90-H-546 36523
90-H-553 36545
90-H-554 36546
90-H-590 36547
90-H-591 36548
90-H-613 36611
90-H-614 36612
90-H-615 36613
90-H-630 36642
90-H-631 36644
90-H-632 36643
90-H-633 36697
90-H-634 36698
90-H-635 36699
90-H-636 36711
90-H-748 37125
90-H-749 37138
90-H-750 37139
90-H-751 37140
90-H-752 37141
90-H-753 90-HC-680 37137
90-H-781 37266
90-H-782 37265
90-H-783 37264
90-H-784 37236
90-H-827 90-HC-740 37342
91-H-47 91-HC-47 37431
91-H-59 37322
91-H-60 37492
91-H-61 37493
91-H-62 91-HC-57 37484
91-H-64 37501
91-H-65 37500
91-H-81 37554
91-H-100 37598
91-H-129 37599
91-H-130 37601
91-H-131 37706
91-H-132 37707
91-H-133 37708
91-H-134 37651
91-H-135 37786
91-H-136 37787
91-H-137 37788
91-H-138 37789
91-H-145 37296
91-H-146 37128
91-H-147 36908
91-H-175 37824
91-H-176 37831
91-H-181 37944
91-H-182 37946
91-H-183 37947
91-H-184 37948
91-H-251 38055
91-H-252 38056
91-H-253 91-HC-222 38098
91-H-254 38054
91-H-296 38139
91-H-297 38140
91-H-298 38141
91-H-299 38142
91-H-300 38143
91-H-301 38160
91-H-302 38177
91-H-340 38088
91-H-341 38089
91-H-342 38101
91-H-343 38102
91-H-344 38103
91-H-345 38104
91-H-346 37945
91-H-347 38169
91-H-348 38171
91-H-349 38172
91-H-350 38173
91-H-351 38197
91-H-352 91-HC-301 38218
91-H-390 38156
91-H-391 38338
91-H-392 38339
91-H-393 38340
91-H-394 38341
91-H-444 91-HC-387 38359
91-H-445 91-HC-388 38360
91-H-504 91-HC-441 38449
91-H-505 91-HC-442 38450
91-H-506 91-HC-443 38451
91-H-507 38281
91-H-508 38283
91-H-509 38284
91-H-510 38285
91-H-511 38286
91-H-512 38287
91-H-513 38288
91-H-514 38290
91-H-515 38291
91-H-516 38297
91-H-517 38298
91-H-518 38434
91-H-519 38452
91-H-520 38471
91-H-521 38170
91-H-522 38269
91-H-523 38335
91-H-524 38387
91-H-525 38388
91-H-592 38293
91-H-593 38299
91-H-594 38302
91-H-595 38515
91-H-596 38548
91-H-598 38300
91-H-599 38301
91-H-600 38303
91-H-601 38611
91-H-618 38292
91-H-619 38295
91-H-620 38296
91-H-621 38304
91-H-622 38665
91-H-630 38294
91-H-631 38605
91-H-632 38606
91-H-633 38607
91-H-634 38608
91-H-635 38609
91-H-636 38610
91-H-637 38690
91-H-638 38691
91-H-639 38707
91-H-640 38741
91-H-641 38809
91-H-642 38810
91-H-643 38811
91-H-648 38827
91-H-649 38828
91-H-680 38857
91-H-681 38856
91-H-682 91-HC-585 38870
91-H-683 38851
91-H-684 38889
91-H-685 38890
91-H-716 38975
91-H-729 91-HC-628 38852
91-H-730 91-HC-629 38853
91-H-746 39065
91-H-747 39066
91-H-748 38850
91-H-791 91-HC-697 39145
91-H-792 91-HC-698 39144
91-H-793 91-HC-699 38722
91-H-794 91-HC-700 38723
91-H-795 39175
91-H-796 39191
91-H-797 91-HC-701 39225
91-H-798 91-HC-702 38720
91-H-799 91-HC-703 39224
91-H-800 91-HC-704 39195
91-H-801 91-HC-705 38721
91-H-802 91-HC-706 39194
91-H-803 91-HC-707 39326
91-H-804 91-HC-708 39196
91-H-805 91-HC-709 39146
91-H-806 39226
91-H-807 39147
91-H-808 39230
91-H-809 91-HC-710 38724
91-H-836 91-HC-736 39092
91-H-837 91-HC-737 39093
91-H-838 91-HC-738 39164
91-H-839 91-HC-739 39165
91-H-840 91-HC-740 39166
91-H-841 91-HC-741 39374
91-H-842 91-HC-742 39375
91-H-843 91-HC-743 39380
91-H-844 91-HC-744 39381
91-H-845 91-HC-745 38346
91-H-869 39342
92-H-31 92-HC-28 39163
92-H-32 92-HC-29 39167
92-H-33 92-HC-30 39168
92-H-34 92-HC-31 39570
92-H-35 92-HC-32 39571
92-H-36 92-HC-33 39572
92-H-37 92-HC-34 39573
92-H-40 92-HC-37 39659
92-H-41 92-HC-38 39657
92-H-42 92-HC-39 39658
92-H-78 92-HC-71 39715
92-H-79 39716
92-H-80 39717
92-H-81 39631
92-H-82 39632
92-H-83 39633
92-H-84 39634
92-H-85 39635
92-H-86 39636
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | In the middle of difficulty
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | lies opportunity --
|_____|/ |_|/ |_____|/ | Albert Einstein
Article: 412
From: yee@trident.arc.nasa.gov (Peter E. Yee)
Newsgroups: sci.space.news
Subject: Currently mounted CD-ROMs in the Ames SPACE Archive
Date: 28 Feb 92 04:52:50 GMT
Sender: usenet
Organization: NASA Ames Research Center, Moffett Field, CA
I've just mounted Magellan, Volumes 18 and 19 in the CD-ROM drives. Access
is via anonymous ftp to ames.arc.nasa.gov (128.102.18.3), in the
pub/SPACE/CDROM and pub/SPACE/CDROM2 directories.
I will be requesting a set of the IRAS discs (for those interested), and will
make them available when I receive them.
-Peter Yee
yee@ames.arc.nasa.gov
|
| 456.469 | MAGELLAN Fact Sheet | VERGA::KLAES | All the Universe, or nothing! | Thu Mar 05 1992 12:09 | 204 |
| Article: 418
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space.news
Subject: Magellan Fact Sheet
Date: 28 Feb 92 22:34:34 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
=====================
MAGELLAN FACT SHEET
February 28, 1992
=====================
*** MISSION SUMMARY ***
The Magellan spacecraft, named after the sixteenth-century Portuguese
explorer whose expedition first circumnavigated the Earth, was launched
May 4, 1989, and arrived at Venus on August 10, 1990. Magellan's solid
rocket motor placed it into a near-polar elliptical orbit around the planet.
During the first 8-month mapping cycle around Venus, Magellan collected
radar images of 84 percent of the planet's surface, with resolution 10 times
better than that of the earlier Soviet Venera 15 and 16 missions. Altimetry
and radiometry data also measured the surface topography and electrical
characteristics. During subsequent cycles the map will be completed,
filling gaps in coverage from the first cycle and imaging the south polar
region for the first time. Precision radio tracking of the spacecraft will
measure Venus' gravitational field to show the planet's internal mass
distribution and the forces which have created the surface features.
Magellan's data will permit the first global geological understanding of
Venus, the planet most like Earth in our solar system.
*** VENUS ***
Distance from Sun: 1.1 x 108 km
Orbit Period: 225 Earth days
Radius: 6051 km
Rotational Period (sidereal): 243 Earth days
Average Density: 5.2 g/cm3
Surface Gravity: .907 times that of Earth
(8.87 m/s2)
Surface Temperature: 850 F (730 K)
Surface Atmospheric Pressure: 90 times that of Earth
(90 q 2 bar)
Atmospheric Composition: Carbon dioxide (96%); nitrogen
(3+%); trace amounts of sulfur
dioxide, water vapor, carbon
monoxide, argon, helium, neon,
hydrogen chloride, hydrogen
fluoride
*** MAJOR MISSION CHARACTERISTICS ***
Interplanetary Cruise: May 4, 1989, to August 10, 1990
First Mapping Cycle: September 15, 1990 to May 15, 1991
Orbit Period: 3.25 hours
Orbit Inclination: 86 degrees
Radar Mapping Per Orbit: 37.2 minutes
Planetary Coverage: 84%
Extended Mission Plan: May 16, 1991 to May 15, 1993
Cycle 2: Image the south pole region and
gaps from Cycle 1
Cycle 3: Fill remaining gaps and collect
stereo imagery
Cycle 4: Measure Venus' gravitational field
*** MISSION OBJECTIVES ***
Obtain near-global radar images of Venus' surface, with resolution
equivalent to optical imaging of 1 km per line pair.
Obtain a near-global topographic map with 50km spatial and 100m vertical
resolution.
Obtain near-global gravity field data with 700km resolution and 2-3
milligals accuracy.
Develop an understanding of the geological structure of the planet,
including its density distribution and dynamics.
*** MAGELLAN TEAM ***
NASA/Solar System Exploration Division
- Elizabeth E. Beyer, Program Manager
- Joseph M. Boyce, Program Scientist
- David J. Okerson, Program Engineer
JPL
- James F. Scott, Project Manager
- R. Stephen Saunders, Project Scientist
- Douglas G. Griffith, Mission Director
Principal Investigators
- Radar: Gordon Pettengill (MIT)
- Gravity: William Sjogren (JPL)
Georges Balmino (France)
System Contractors
- Spacecraft: Martin Marietta/Denver
F. McKinney, Manager
- Radar: Hughes Aircraft
B. Dagarin, Manager
*** KEY SPACECRAFT CHARACTERISTICS ***
Single radar instrument operates simultaneously (by interleaving) in
Synthetic Aperture Radar (SAR), altimeter, and radiometer modes.
High Gain Antenna (3.7m diameter) is used as both the radar and
telecommunications antenna.
X-band downlink data rate of 268.8 or 115 kbps.
Coherent X- and S-band radio subsystem used for gravity field measurement
by precision tracking of the spacecraft's orbit.
Spacecraft on-orbit dry mass of 1035 kg.
Monopropellant hydrazine thruster system (0.9 to 445N thrust).
Powered by solar panels with rechargeable batteries.
Three orthogonal electrically powered reaction wheels used for spacecraft
pointing control.
*** KEY RADAR CHARACTERISTICS ***
Synthetic Aperture Radar (SAR)
- Frequency 2.385 GHz
- Peak Power 325 W
- Pulse Length 26.5 microsecond
- PRF 4400-5800 Hz
- Swath Width 25 km (variable)
- Data Acquisition Rate 806 kbps
- Downlink Quantization 2 bits
Operates in SAR, altimeter, and radiometer modes
- SAR Resolution 150m range/150m azimuth
- Altimeter Resolution 30m
- Radiometer Accuracy 2 C
Operating parameters controlled by ground command
*** KEY SCIENTIFIC RESULTS ***
A preliminary assessment of the Magellan high-resolution global images is
providing evidence to understand the role of impacts, volcanism, and
tectonism in the formation of Venusian surface structures.
The surface of Venus is mostly covered by volcanic materials. Volcanic
surface features, such as vast lava plains, fields of small lava domes, and
large shield volcanoes are common.
There are few impact craters on Venus, suggesting that the surface is, in
general, geologically young - less than 800 million years old.
The presence of lava channels over 6,000 kilometers long suggests river-like
flows of extremely low-viscosity lava that probably erupted at a high rate.
Large pancake-shaped volcanic domes suggest the presence of a type of lava
produced by extensive evolution of crustal rocks.
The typical signs of terrestrial plate tectonics - continental drift and
basin floor spreading - are not in evidence on Venus. The planet's
tectonics is dominated by a system of global rift zones and numerous broad,
low domical structures called coronae, produced by the upwelling and
subsidence of magma from the mantle.
Although Venus has a dense atmosphere, the surface reveals no evidence of
substantial wind erosion, and only evidence of limited wind transport of
dust and sand. This contrasts with Mars, where there is a thin atmosphere,
but substantial evidence of wind erosion and transport of dust and sand.
*** FOR MORE INFORMATION ON DATA ***
Photographic images, digital data (CD ROMs) and display software, and
videotapes showing computer-generated flights over Venus are available to
researchers, educators, and the public through the National Space Science
Data Center, Goddard Space Flight Center, Mail Code 933.4, Greenbelt,
MD 20771, (301) 286-6695, Fax: (301) 286-4952.
Digital data and detailed catalog information are available to researchers
funded by NASA's Solar System Exploration Division through the Planetary
Data System, Geosciences Node, Earth and Planetary Remote Sensing
Laboratory, Washington University, St. Louis, MO 63130-4899, (314) 935-5493,
Fax: (314) 935-7361.
Photographic imagery, CD-ROMs, and videotapes are available for browsing at
NASA's 15 Regional Planetary Image Facilities.
For additional information, call Mary Ann Harger at the Lunar and Planetary
Institute at (713) 486-2136 or -2172, Fax: (713) 486-2153.
Teachers can obtain information about Magellan, including copies of the
videotapes, through NASA's Teacher Resource Centers. For more information,
call the Jet Propulsion Laboratory's Teacher Resource Center at
(818) 354-6916, Fax: (818) 354-8080.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | In the middle of difficulty
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | lies opportunity --
|_____|/ |_|/ |_____|/ | Albert Einstein
|
| 456.470 | Update - March 4 | VERGA::KLAES | All the Universe, or nothing! | Wed Mar 11 1992 15:36 | 38 |
| Article: 471
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space.news
Subject: Magellan Update - 03/04/92
Date: 9 Mar 92 12:14:48 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from:
PUBLIC INFORMATION OFFICE
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIF. 91109. TELEPHONE (818) 354-5011
MAGELLAN STATUS REPORT
March 4, 1992
The Magellan spacecraft continues to map Venus under a command
sequence which started last Friday. All systems are normal and
pointing accuracy of the antenna is excellent.
The telecommunications signal level decreased last Sunday and the
Deep Space Network was unable to receive the high rate data. Tests
indicated a temperature problem caused by a recent change in the solar
panel position.
Controllers made the appropriate changes and the high data rate
was received again as of Wednesday morning and stereo mapping of key
surface features was resumed.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | In the middle of difficulty
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | lies opportunity --
|_____|/ |_|/ |_____|/ | Albert Einstein
|
| 456.471 | Updates - February 24 to March 13 | VERGA::KLAES | All the Universe, or nothing! | Mon Mar 16 1992 20:34 | 309 |
| Article: 510
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space.news
Subject: Magellan Updates - 02/24/92 to 03/12/92
Date: 14 Mar 92 01:39:28 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from the Magellan Project.
Magellan Status Reports, February 24, 1992 through March 12, 1992
MAGELLAN STATUS REPORT - Monday, 2-24-92
1. Magellan continues to map Venus to provide stereo images of
an equatorial region near Sappho Patera. So far in Cycle 3, the
spacecraft has mapped about 3.5% of the surface.
2. All spacecraft systems are nominal and pointing accuracy of the
antenna remains excellent. Only one star was missed during
starcals (star calibrations) over the weekend. 3. Bay 7 (which
contains the Command and Data Subsystem) peaked at 56.7 degrees C
during the weekend, but now seems to be cooling.
4. The DSN (Deep Space Network) stations continue to receive
satisfactory high rate data using the 360 kHz subcarrier at 115.2 kbps.
5. Magellan has now completed 3611 mapping orbits of Venus, 225
orbits since the resumption of mapping in Cycle 3 .
MAGELLAN STATUS REPORT - Tuesday, 2-25-92
1. Magellan continues to map Venus to provide stereo images of
an equatorial region near Sappho Patera.
2. All spacecraft systems are nominal and pointing accuracy of
the antenna remains excellent. Bay 7 (which contains the Command
and Data Subsystem) peaked at 56.7 C degrees during the weekend, but now
seems to be cooling.
4. The DSN stations continue to receive satisfactory high rate
data using the 360 kHz subcarrier at 115.2 kbps.
5. Magellan has now completed 3618 mapping orbits of Venus, 233
orbits since the resumption of mapping in Cycle 3. So far in
Cycle 3, the spacecraft has mapped about 3.5% of the surface.
MAGELLAN STATUS REPORT - Wednesday, 2-26-92
1. No Report
MAGELLAN STATUS - Thursday, February 27, 1992:
1. Magellan continues to map Venus under the M2052 command
sequence which started a week ago. All systems are nominal and
pointing accuracy of the antenna is excellent.
2. Magellan is sending high rate data using the 360 kHz subcarrier
at 115.2 kbps, and the signal-to-noise ratio remains acceptable.
MAGELLAN STATUS - Friday, February 28, 1992:
1. Magellan continues to map Venus under the M2052 command
sequence which started a week ago. All systems are nominal and
pointing accuracy of the antenna is excellent.
2. Magellan is sending high rate data using the 360 kHz subcarrier
at 115.2 kbps, and the signal-to-noise ratio remains acceptable.
3. Magellan has now completed 492 days of radar mapping,
completing 3642 mapping orbits. Approximately 97% of the Venus
surface has been imaged, with about 45% doubly covered with
right-look or stereo imagery.
MAGELLAN STATUS REPORT - Monday, March 2, 1992:
1. Magellan continues to map Venus under the M2052 command
sequence which started last Friday. All systems are nominal and
the DSN stations continue to receive satisfactory high rate data
using the 360 kHz subcarrier at 115.2 kbps.
2. Magellan has now completed 3641 mapping orbits of Venus.
Nearly all of the 255 orbits completed in Cycle 3 have provided
stereo coverage of areas mapped during Cycle 1. However, part of
the present command sequence is designed to fill part of the
small gaps remaining from Cycle 1.
MAGELLAN STATUS - Tuesday, March 3, 1992: No Report
MAGELLAN STATUS - Wednesday, March 4, 1992:
1. Magellan continues to map Venus under the M2052 command
sequence which started last Friday. All systems are nominal and
pointing accuracy of the antenna is excellent.
2. The telecommunications signal level decreased on Sunday to
where the DSN stations were unable to lock-up on the high rate
data. Yesterday, four uploads were sent to the spacecraft to
characterize the main carrier signal and the subcarriers.
3. As of this morning, we are again receiving high rate data
using the 360 kHz subcarrier at 115.2 kbps. The signal-to-noise
ratio is averaging .7, with a range from .2 to 1.2. We are also
receiving 40 bps engineering telemetry.
4. Temperatures on the -X side of the Forward Equipment Module
(FEM) have risen about 2 degrees C. This is caused by a recent
change in the solar panel offpoint from 45 degrees to zero.
5. Spacecraft controllers plan to uplink commands tomorrow to
adjust the Solar Array Drive Mechanism commanded position.
MAGELLAN STATUS - Thursday, March 5, 1992: No Report
MAGELLAN STATUS - Friday, March 6, 1992:
1. Magellan continues to map Venus under the M2052 command
sequence which started a week ago last Friday. All systems are
nominal and pointing accuracy of the antenna is excellent.
2. Magellan is sending high rate data using the 360 kHz
subcarrier at 115.2 kbps, although there have been some problems
at the DSN stations related to weather. During the past two days,
lightning strikes have affected equipment at the Madrid and
Canberra stations, and Goldstone station 15 has had trouble
locking up this morning due to a storm moving through Southern
California.
3. Yesterday spacecraft controllers uplinked commands to switch
off the subcarrier for five minutes in order to obtain spectrum
plots of the main carrier, and to update the Solar Array Drive
Mechanism commanded position.
4. For the past week Magellan has been in a period of increasing
solar occultations, i.e. time in the shadow of Venus. The
temperature changes affect the frequency of the signal spur and
its harmonics which, in turn, limit the performance of
Transmitter B, so telecommunications engineers will continue to
take daily spectrum plots to closely monitor the
telecommunications system.
MAGELLAN STATUS - Monday, March 9, 1992:
1. Magellan continues to map Venus near the end of the M2052
command sequence which started 17 days ago. All systems are
nominal and pointing accuracy of the antenna is excellent.
2. Magellan is sending high rate data using the 360 kHz
subcarrier at 115.2 kbps, although the signal-to-noise ratio
remains marginal. The DSN stations report high error counts in
the data. The data improves as the Transmitter B temperature
rises during playback periods.
3. On Friday spacecraft controllers uplinked commands to change
the radar heater set points. Radar system temperatures are now
between 29 and 30 degrees C. Transmitter B is at 47 degrees C.
4. Later today the M2070 command sequence will be sent to
Magellan and will go active tomorrow at 11:30 AM PST. This
sequence will map from 42 degrees north latitude to 45 degrees
south latitude.
5. For the past two weeks Magellan has had increasing solar
occultations, i.e. time in the shadow of Venus, so cooling
periods ("hides") are not required in the M2070 sequence.
MAGELLAN STATUS - Tuesday, March 10, 1992:
1. Magellan continues to map Venus as we approach the start of
the M2070 command sequence this morning. All systems are nominal
and pointing accuracy of the antenna is excellent.
2. During the past 24 hours the spacecraft had another spurious
shutoff of the Traveling Wave Tube Amplifier (TWTA). The
automatic restart process configures the telecommunications to
the 960 kHz subcarrier, so we lost about two orbits of data
before we were able to obtain engineering telemetry and correct
the configuration.
3. Magellan is sending high rate data using the 360 kHz
subcarrier at 115.2 kbps, but the DSN stations are able to
maintain two-way lock up only about 50% of the time.
4. The M2070 command sequence which will go active today at 11:30
AM PST will map from 42 degrees north latitude to 45 degrees
south latitude.
5. For the past two weeks Magellan has had increasing solar
occultations, i.e. time in the shadow of Venus, so cooling
periods ("hides") are not required in the M2070 sequence. The
solar occultations are presently about 55 minutes long .
MAGELLAN STATUS - Wednesday, March 11, 1992:
1. Magellan continues to map Venus under the M2070 command
sequence which started yesterday. All systems are nominal and
pointing accuracy of the antenna is excellent. The present
mapping passes are from 42 degrees north latitude to 45 degrees
south latitude.
2. Magellan is sending high rate data using the 360 kHz
subcarrier at 115.2 kbps, but the DSN stations are able to
maintain two-way lock up only about 50% of the time. The signal-
to-noise ratio is presently .8.
3. For the past three weeks Magellan has had increasing solar
occultations, i.e. time in the shadow of Venus, so cooling
periods ("hides") are not required in the M2070 sequence. The
solar occultations are presently about 55 minutes long.
4. Earth occultations (that is, periods when the orbit passes
behind Venus as views from Earth) ended yesterday.
MAGELLAN STATUS - Thursday, March 12, 1992:
1. Magellan continues to map Venus under the M2070 command
sequence which started Tuesday. All systems are nominal and
pointing accuracy of the antenna is excellent. The present
mapping passes are from 42 degrees north latitude to 45 degrees
south latitude.
2. Yesterday, spacecraft controllers sent commands to raise the
radar system heater set points to 35 degrees C. This, in turn,
raised the Transmitter B temperature to 49-50 degrees and
improved the performance slightly.
3. Currently the signal-to-noise ratio for the high rate data is
averaging 0 db, and the SNR for the 40 bps engineering telemetry
is 3-6 db.
4. Magellan continues to send high rate data using the 360 kHz
subcarrier at 115.2 kbps, and as long as we have a positive SNR
the data is processable into images.
5. Later today, controllers will send up a "pseudo-tweak," a
routine update to the radar mapping parameters. They also plan to
send up commands to perform a two-orbit test of 1200 bps
telemetry tomorrow. A switch to 1200 bps from the present 40 bps
rate would greatly improve the information available to the
spacecraft team for monitoring Magellan's health.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | In the middle of difficulty
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | lies opportunity --
|_____|/ |_|/ |_____|/ | Albert Einstein
Article: 513
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space.news
Subject: Magellan Update - 03/13/92
Date: 14 Mar 92 03:31:58 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from the Magellan project.
MAGELLAN STATUS REPORT
March 13, 1992
1. Magellan continues to map Venus under the M2070 command
sequence which started Tuesday.
2. Yesterday, spacecraft controllers sent routine commands to
configure the fault protection and the "pseudo-tweak." This
morning, commands were sent to switch the engineering telemetry
to 1200 bps for two orbits.
3. Currently the signal-to-noise ratio for the high rate data is
averaging 0 db, and the SNR for the 40 bps engineering telemetry
is 3-6 db.
4. Fred Linkchorst of the Radar Team has analyzed the
correlation between SNR and the percent of usable radar data in
the record. When the SNR is above -.5, then 70% of the burst
headers are present and 95% of the radar composite data frames
are present.
5. The telecommunications engineers now believe we can keep the
SNR in the desired range if Transmitter B is maintained at about
49-50 degrees. The Transmitter is presently at 49.8 degrees C.,
with a cycle of three degrees.
6. Yesterday, Project Scientist Steve Saunders gave a briefing
to the Magellan flight team, showing the exciting results of imaging
to date and some of the puzzling differences between Cycle 1, 2
and 3 images.
7. Sasha Basilevsky, guest investigator from the Russian
Republic, described some of the studies matching Magellan mosaics
to Venera landing sites.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | In the middle of difficulty
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | lies opportunity --
|_____|/ |_|/ |_____|/ | Albert Einstein
|
| 456.472 | MAGELLAN items available | VERGA::KLAES | All the Universe, or nothing! | Mon Mar 16 1992 20:36 | 77 |
| Article: 482
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space.news
Subject: More Magellan Goodies Available (Macintosh)
Date: 12 Mar 92 02:13:42 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
===============================
MAGELLAN PRODUCTS (Macintosh)
March 11, 1992
===============================
The following Magellan items are now available for the Macintosh
computer at the Ames site using anonymous ftp:
o Magellan Image Atlas program
o Five Magellan StartupScreen images
o Magellan captions file in Hypercard 2.1 format
A Macintosh version of the Magellan Image Atlas program if now available.
It has been compressed with STUFFIT and uploaded in Macbinary format. The file
contains an application program which can find the location (lat/long) of named
features on Venus, and the CD-ROM and mosaic which lie on any given lat/long
on Venus.
ftp: ames.arc.nasa.gov (128.102.18.3)
user: anonymous
cd: pub/SPACE/SOFTWARE
files: magellan.sit (Stuffit, MacBinary format)
Five more Magellan images are now available that can be displayed on the
older black-and-white Machintoshes. Each image 22 KB each and show parts of
the Gula Rift 3D image (gula.mac, gula_rift.mac, sif.mac), the "tick"
(tick.mac) and Alcott crater (alcott.mac). If the images are placed in the
System folder of the computer and named "StartupScreen", the images will
automatically be displayed when the computer is turned on. The images have
been dithered to replace the grey values with varying densities of black and
white and are stored in the MacBinary format. Obviously, the image quality is
not as good as a grey scale display, but it is surprisingly good. The same
images can also be displayed as MacPaint files.
ftp: ames.arc.nasa.gov (128.102.18.3)
user: anonymous
cd: pub/SPACE/MAGELLAN
files: alcott.mac (MacBinary format)
gula.mac (MacBinary format)
gula_rift.mac (MacBinary format)
sif.mac (MacBinary format)
tick.mac (MacBinary format)
The captions files for the Magellan images is now in another format.
The file "captions.hqx" is a BINHEX converted file of a Hypercard 2.1 stack
compressed with STUFFIT. (That is, to get the original back, download the
captions.hqx, open the STUFFIT program, unencode the BINHEX file, and then
open the resulting *.SIT file.) The STUFFED file contains the program
Hypercard 2.1 and a stack which lets you find and read the Magellan captions.
These caption files are the text that goes along with each of the public
released Magellan images, and provides a detailed description of each
image. The caption files are also provided in other formats.
ftp: ames.arc.nasa.gov (128.102.18.3)
user: anonymous
cd: pub/SPACE/MAGELLAN
files: captions.hqx (BINEX, Hpercard 2.1 -> Stuffit)
captions.txt (ASCII)
caps_wp5.zip (IBM PC Wordperfect 5.1 -> PKZIP)
caps_wrd.zip (IBM PC Word -> PKZIP)
captions.sit (Macintosh Word -> Stuffit)
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | In the middle of difficulty
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | lies opportunity --
|_____|/ |_|/ |_____|/ | Albert Einstein
|
| 456.473 | The Flat Venus Society | VERGA::KLAES | All the Universe, or nothing! | Mon Mar 16 1992 21:30 | 30 |
| Article: 21043
From: martin@space.ualberta.ca (Martin Connors)
Newsgroups: sci.space,sci.astro,sci.geo.geology
Subject: Flat Venus Society
Date: 16 Mar 92 17:44:09 GMT
Sender: news@kakwa.ucs.ualberta.ca
Organization: University Of Alberta, Edmonton Canada
The March 3, 1992 issue of EOS has a letter from David Morrison
(NASA Ames) proposing formation of a "Flat-Venus Society" to combat
the impression given by JPL flyover videos of a very mountainous
Cytherian terrain. The 20-23 times vertical exagerration used
certainly does give that impression. In fact Venus is an incredibly
flat place by terrestrial standards, the only precipitous area I can
think of offhand being the western slopes of Maxwell Montes. Ellen
Stofan rebuts that the exagerrated images are used in analysis and
should not be "watered down" for public consumption.
Interesting enough, in a recent talk to the local astronomy club,
I made exactly that point about vertical exagerration and backed it up
by showing Pioneer Venus global topography. I think it is important
that one stress this in talking to the public, but on the other hand
the vertical exagerration is clearly very helpful in seeing detail.
And if soaring peaks and enhanced valleys excite people about space,
let's use them!
Martin Connors
Space Research
University of Alberta
|
| 456.474 | Magellan to orbit just above Venus' dense atmosphere | PRAGMA::GRIFFIN | Dave Griffin | Mon Mar 16 1992 23:29 | 58 |
| Paula Cleggett-Haleim
Headquarters, Washington, D.C.
Jim Doyle
Jet Propulsion Laboratory, Pasadena, Calif.
RELEASE: 92-36
The Magellan spacecraft's orbit around Venus will be lowered later this
year to just above the planet's dense atmosphere to conduct gravity studies of
Venus, it was announced today at the Lunar and Planetary Science Conference in
Houston.
Magellan continues to map a region near the Equator of Venus to provide
three-dimensional, high-resolution views of the highlands of Aphrodite Terra.
The stereo mapping phase, which began Jan. 26 near Maxwell Montes, the
highest mountain on Venus, will end in mid- September, said Project Scientist
Dr. Stephen Saunders. The orbit at its closest point to the planet will be
lowered later that month. Magellan is in its third mapping cycle around Venus.
The spacecraft's closest approach to Venus will be moved downward from
186 miles to 111 miles above the surface for maximum sensitivity to variations
in the gravity field, he said.
Gravity is mapped by analyzing slight variations in Magellan's radio
signal sent back to Earth. Gravity mapping is planned for a complete 243- day
cycle, or one Venus rotation, during the fourth cycle around Venus.
In the first 243-day mapping cycle, Magellan mapped 84 percent of Venus
and at the end of the second cycle, had mapped 94 percent, providing a
near-global view. This map revealed wind patterns from the distribution of
wind-blown deposits of sand and dust.
Although no Earth-like plate tectonic features have been identified,
Saunders said, the global distribution of fractures and various terrain types
can be determined.
In the second cycle, Magellan pointed its imaging radar to the opposite
side, mapping to the right. Most of the features look similar, but some appear
very different from the opposite angle, he said. The right- pointing imaging
also allowed the first views of Venus' south polar region.
A thick volcanic lava field has been measured from opposite sides
revealing a thickness of about 3,000 feet of congealed lava. The lava was once
a thick, viscous molten rock that poured from the subsurface of Venus.
Impact craters on Venus also can produce flows that resemble volcanic
flows. One of the puzzles is why some large impact craters appear to have
produced large volumes of lava-like flows and others do not produce flows at
all, Saunders said.
Detailed shapes of impact craters also are being determined from
opposite side images and stereo.
JPL manages the Magellan Project for NASA's Office of Space Science and
Applications.
|
| 456.475 | Misc Magellan files | PRAGMA::GRIFFIN | Dave Griffin | Mon Mar 16 1992 23:41 | 15 |
| I have retrieved 2 of the 3 3D GIF files, the 3rd one should be here soon
(I just forgot that there were 3 of them!).
Look for mgn_*_3D.gif in pragma::public:[nasa]
I normally don't go after the Mac bitonal stuff, so if you want them send
me mail (there are Mac utilities that can convert GIF files just fine so I
really don't see the need for them.) PDS files can also be obtained by
asking (subject to my schedule, etc.).
FYI,
- dave
|
| 456.476 | Update - March 19; new CD-ROMs | VERGA::KLAES | All the Universe, or nothing! | Mon Mar 23 1992 22:30 | 108 |
| Article: 553
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space.news
Subject: Magellan Update - 03/19/92
Date: 20 Mar 92 05:30:46 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from:
PUBLIC INFORMATION OFFICE
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIF. 91109. TELEPHONE (818) 354-5011
MAGELLAN STATUS REPORT
March 19, 1992
The Magellan spacecraft continues to map the western portion
of Aphrodite Terra on Venus from 42 degrees north latitude to 45
degrees south. Those images when coupled with cycle 1 coverage,
provide stereo pairs of the area and enable scientists to do
precise three-dimensional analysis of surface features.
Spacecraft systems remain normal. A new sequence will be
uplinked later today to begin execution Friday morning. It will
include a new look at the so-called "landslide," an area of
possible surface change discovered in the first eight-orbit
stereo radar test during cycle 2.
The new look may help resolve whether the area was indeed a
landslide as some scientists first thought, or an artifact of
radar imaging as other experts believed.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | People will believe
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | anything if you whisper it.
|_____|/ |_|/ |_____|/ |
Article: 561
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space.news
Subject: Magellan CD-ROMs
Date: 21 Mar 92 06:39:39 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
=====================================
MAGELLAN CD-ROMs
March 20, 1992
=====================================
Six more Magellan CD-ROMs (volumes 43 through 48) have been released by
the Magellan project. A total of 48 Magellan CD-ROMs has now been released.
The CD-ROMs contain the radar images taken by the Magellan spacecraft during
its first 8 month mapping cycle of the planet Venus. The Magellan project is
continuing to produce CD-ROMs at the rate of about 8 per month. The full set
of the Cycle 1 radar images will consist of 52 CD-ROMs, plus an additional 10
CD-ROMs for the altimeter data which will be released later in the year.
The CD-ROMs can be obtained from the National Space Science Data Center
(NSSDC) at the Goddard Space Flight Center. The "nominal" charge is $20 for
the first CD-ROM, and $6 for any additional CD-ROM in an order. However,
NSSDC may waive this charge for a small amount of data requested by bona fide
research users, government laboratories, etc. School teachers who are unable
to pay may be helped on a case by case basis, and/or as resources permit.
Researchers funded by NASA's Solar System Exploration Division can also obtain
the CD-ROMs through the Planetary Data System at JPL.
NSSDC's address is:
National Space Science Data Center
Goddard Space Flight Center
Greenbelt, Maryland 20771
Tel: (301) 286-6695
Email address: request@nssdca.gsfc.nasa.gov
You can also reach NSSDC by logging on to their computer. To log onto the
NSSDC computer, telnet to NSSDC.GSFC.NASA.GOV [128.183.36.25] and give the
username "NSSDC". You will then be connected to a menu system which allows
you to use the "Master Directory". You can also leave questions and orders for
the NSSDC staff. If this is the first time you have used the NSSDC "NODIS"
system, it will ask you for information (name, address, ...) to keep a database
of NSSDC users.
NSSDC also provides the following software to display the images:
o IMDISP (IBM PC)
o Browser (Macintosh)
o Pixel Pusher (Macintosh)
o True Color (Macintosh)
The Magellan CD-ROMs are also available via anonymous ftp at the Ames
Research Center: ames.arc.nasa.gov [128.102.18.3]. The Ames site has two
CD-ROM drives and they are accessible through the pub/SPACE/CDROM and
pub/SPACE/CDROM2 directories. The CD-ROMs are rotated on a weekly basis.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | People will believe
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | anything if you whisper it.
|_____|/ |_|/ |_____|/ |
|
| 456.477 | Updates - March 16-25 | VERGA::KLAES | All the Universe, or nothing! | Thu Mar 26 1992 20:30 | 445 |
| Article: 575
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space.news
Subject: Magellan Update - 03/16/92
Date: 24 Mar 92 08:17:11 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from the Magellan Project.
MAGELLAN STATUS REPORT
March 16, 1992
1. Magellan continues to map Venus under the M2070 command
sequence which started last week. All systems are nominal
and pointing accuracy of the antenna is excellent. Only
one star calibration was missed over the weekend.
2. Magellan is sending radar image data using the 360 kHz
subcarrier at 115.2 Currently the signal-to-noise ratio
for the high rate data ranges between 0 and +2 db.
3. The Radar System Engineering Team displayed a radar image
this morning in which the SNR ranges between -2.5 and -0.5
db. It demonstrates that very useful images can be
obtained when the SNR is -1 db or higher.
4. Later today spacecraft controllers will uplink the "pseudo-tweak,"
a routine update of the radar control parameters.
5. The attached table shows some Magellan mission statistics
for today, March 16, 1992.
------------------------------------
MAGELLAN IMAGE COVERAGE
FROM SEPTEMBER 15, 1990 TO MARCH 16, 1992:
DAYS
TOTAL DAYS . . . . . . . . . . . . . . . . .. . . . 545 DAYS
SUPERIOR CONJUNCTION - 15
TRANSMITTER ANOMALY (JAN. 1992) - 19
BATTERY RECONDITIONING (JAN. 1992) - 7
DAYS OF MAPPING . . . . . . . . . . . . . . . . . . 504
ORBITS
TOTAL ORBITS . . . . . . . . . . . . . . . . . . . . 4037 ORBITS
SUPERIOR CONJUNCTION -110
ORBIT TRIM MANEUVER (5-17-91) - 4
BATTERY RECONDITIONING - 54
TRANSMITTER ANOMALY (JAN-MAR 1992) -122
MAPPING ORBITS . . .. . . . . . . . . . . . . . . . . 3746
PERCENTAGE OF VENUS SURFACE AREA
TOTAL AREA SWEPT BY ORBITS (CYCLE 1) . . . . . . . . . .100.0%
SUPERIOR CONJUNCTION GAP - 6.2%
SOUTH POLAR GAP - 1.5%
AREA COVERED BY MAPPING ORBITS . . . . . . . . . . . . 92.3%
LOSSES IN CYCLE 1 - 8.6% *
TOTAL CYCLE 1 COVERAGE: . . . 83.7%
TOTAL CYCLE 2 COVERAGE: 54.5%
TOTAL CYCLE 3 COVERAGE TO DATE 3.3%
NEW CYCLE 2 COVERAGE:
SOUTH POLAR GAP: +1.3%
SUPERIOR CONJ. GAP: 5.2%
RECOVERY OF DMS-A GAPS 1.4%
RECOVERY OF TWO-HIDE GAPS 2.6%
SOUTH OCCULTED MAPPING GAP .8%
MISCELLANEOUS RECOVERED GAPS 2.2% .+13.3%
PERCENTAGE OF VENUS SURFACE IN CAPTURED DATA . . . . . . 97.2%
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | People will believe
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | anything if you whisper it.
|_____|/ |_|/ |_____|/ |
Article: 576
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space.news
Subject: Magellan Update - 03/17/92
Date: 24 Mar 92 08:23:39 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from the Magellan Project.
MAGELLAN STATUS REPORT
March 17, 1992
1. Magellan continues to map Venus under the M2070 command
sequence which started last week. All systems are
nominal, temperatures of critical systems are stable, and
all starcals yesterday were successful.
2. Magellan continues to send radar image data using the 360
kHz subcarrier at 115.2 Currently the signal-to-noise
ratio for the high rate data ranges 12 db. The Radar Team
has demonstrated that very useful images can be obtained
when the SNR is -1 db or higher.
3. Yesterday spacecraft controllers uplinked the "pseudo-
tweak," a routine update of the radar control parameters.
No commanding is scheduled for today.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | People will believe
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | anything if you whisper it.
|_____|/ |_|/ |_____|/ |
Article: 577
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space.news
Subject: Magellan Update - 03/18/92
Date: 24 Mar 92 08:24:55 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from the Magellan Project.
MAGELLAN STATUS REPORT
March 18, 1992
1. Magellan continues to map Venus under the M2070 command
sequence which started March 10. All systems are nominal
and pointing accuracy of the antenna is excellent. The
present mapping passes are from 42 degrees north latitude
to 45 degrees south latitude.
2. Magellan is sending high rate data using the 360 kHz
subcarrier at 115.2 kbps and the signal-to-noise ratio
remains satisfactory.
3. However, DSN station 15 (Goldtone 34 meter antenna) has a
problem this morning with its antenna subreflector controller,
so Station 12 (Goldtone's other 34 meter antenna) was requested
as back-up. Following the Voyager tracking pass this morning,
Station 12 was scheduled to support a Giotto GDS (Ground Data Systems)
test, but it has been released.
4. The spacecraft temperatures have remained stable, with
Transmitter B holding at 49.8 degrees C. The cycle depth
is still 3.5 degrees C.
5. This week, many of the Magellan Science Team members are
attending the Lunar & Planetary Science Conference in
Houston, where our mission results are being presented in
several sessions.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | People will believe
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | anything if you whisper it.
|_____|/ |_|/ |_____|/ |
Article: 578
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space.news
Subject: Magellan Update - 03/19/92
Date: 24 Mar 92 08:26:15 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from the Magellan Project.
MAGELLAN STATUS REPORT
March 19, 1992
1. Magellan continues to map the western portion of Aphrodite
Terra on Venus, from 42 degrees north latitude to 45
degrees south. These images provide stereo pairs of the
area when coupled with Cycle 1 coverage and enable scientists
to do precise 3-dimensional analysis of surface features.
2. The spacecraft remains nominal. The Transmitter B
temperature has risen slightly, to 50.5 degrees C.
3. Late today, spacecraft controllers will uplink the M2080
command sequence which begins execution at 9:50 AM PST tomorrow.
4. This new sequence will include a new look at the so-called
"Landslide," an area of possible surface change discovered
in the first 8-orbit stereo radar test during Cycle 2.
5. Scientists were excited by what appeared to be a massive
landslide, when comparing Cycle 1 and 2 images. Other
experts believed the feature could be an artifact of radar
imaging called "layover." The new look will help to
resolve this issue.
6. The Magellan mission is approaching Superior Conjunction,
when Venus is on the far side of the Sun from Earth and
communications become difficult. During Cycle 1, this
period caused a gap of 110 orbits, most of which was
covered in Cycle 2.
7. This year, Superior Conjunction occurs on June 14 and the
nominal "gap" in radar mapping is predicted to extend from
June 4 thru 24. However, with the noisy performance of
Transmitter B, the gap could be as much as 12 weeks.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | People will believe
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | anything if you whisper it.
|_____|/ |_|/ |_____|/ |
Article: 579
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space.news
Subject: Magellan Update - 03/20/92
Date: 24 Mar 92 08:27:56 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from the Magellan Project.
MAGELLAN STATUS REPORT
March 20, 1992
1. Magellan continues to map the western portion of Aphrodite
Terra on Venus, from 42 degrees north latitude to 45
degrees south. These images provide stereo pairs of the
area when coupled with Cycle 1 coverage and enable scientists
to do precise 3-dimensional analysis of surface features.
2. The spacecraft remains nominal. The Transmitter B
temperature has risen slightly, to 50.5 degrees C.
3. Yesterday, spacecraft controllers uplinked the M2080
command sequence which began execution at 9:50 AM PST today.
4. This new sequence includes a new look at the so-called
"Landslide," an area of possible surface change
discovered in the first 8-orbit stereo radar test during
Cycle 2. Scientists were excited by what appeared to be
a massive landslide, when comparing Cycle 1 and 2 images.
Other experts believed the feature could be an artifact of
radar imaging called "layover."
5. The new look, to be obtained on Sunday, will help to
resolve this issue.
6. The Magellan mission is approaching Superior Conjunction,
when Venus is on the far side of the Sun from Earth and
communications become difficult. During Cycle 1, this
period caused a gap of 110 orbits, most of which was
covered in Cycle 2.
7. This year, Superior Conjunction occurs on June 14 and the
nominal "gap" in radar mapping is predicted to extend from
June 4 thru 24. However, with the noisy performance of
Transmitter B, the gap could be as much as 12 weeks.
8. Following the period of Superior Conjunction, radar
mapping will be resumed and will continue at least through
the end of Cycle 3 on Sept. 15, 1992.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | People will believe
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | anything if you whisper it.
|_____|/ |_|/ |_____|/ |
Article: 580
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space.news
Subject: Magellan Update - 03/23/92
Date: 24 Mar 92 08:29:22 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from the Magellan Project.
MAGELLAN STATUS REPORT
March 23, 1992
1. Magellan continues to map Venus under the M2080 command
sequence which started last week. All systems are nominal
and all starcals (star calibrations) over the weekend were
successful.
2. Magellan is sending radar image data using the 360 kHz
subcarrier at 115.2 kbps. Transmitter B is presently at
51.2 degrees C. and has peaked at 51.9, but the signal-to-
noise ratio for the high rate data continues to be satisfactory.
3. Yesterday, spacecraft controllers uplinked special radar
control parameters to perform imaging of the so-called
'landslide' during orbits 4456 thru 4458.
4. The test was apparently successful and will provide a new
look at an area which seemed to show a major landslide
during the 7 month period between Cycle 1 and 2.
5. One possibility is that the landslide is simply an
artifact of radar image processing called 'layover'.
If, however, the new image confirms that it is a recent
surface change, it would indicate that the geologic
processes on Venus are very active.
6. Magellan's results were a major topic at last week's Lunar
& Planetary Science Conference in Houston, with six
sessions (plus a poster session) devoted to presentations
by Magellan scientists and other investigators using
Magellan data.
7. Ellen Stofan, Deputy Project Scientist, was one of the
featured lecturers at the 1st Harold Masursky public
lectures, a memorial to the world-reknown planetary
scientist who died in 1990. Ellen spoke on "The Geology
of Venus from Masursky to Magellan.
8. The National Space Science Data Center (NSSDC) reports that over
4500 Magellan CD-ROMs have been delivered by NSSDC to
researchers. These are in addition to those delivered by
PDS (Planetary Data Systems) to existing planetary scientists.
9. Magellan has now completed 430 mapping orbits in its third
mapping cyle of Venus and is 28% of the way through the cycle.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | People will believe
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | anything if you whisper it.
|_____|/ |_|/ |_____|/ |
Article: 591
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space.news
Subject: Magellan Update - 03/24/92
Date: 25 Mar 92 07:15:05 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from the Magellan Project.
MAGELLAN STATUS REPORT
March 24, 1992
1. Magellan continues to map Venus under the M2080 command
sequence which started last week. All systems are
nominal, temperatures of critical systems are stable, and
all starcals (star calibrations) yesterday were successful.
2. Magellan continues to send radar image data using the 360 kHz
subcarrier at 115.2 .
3. No commanding is scheduled for today, but controllers are
planning to uplink changes to the fault protection
configuration tomorrow.
4. During two recent spurious shutoffs of the Travelling Wave
Tube Amplifier (TWTA SSO's), there was a short delay in
re-establishing communications because the automatic
restart process selected the 960 kHz subcarrier.
5. Since we are now using the 360 kHz subcarrier to avoid the
signal spur on Transmitter B, the fault protection needs
to be reconfigured to automatically select this subcarrier.
6. The 15th meeting of the Brown-Vernadsky Microsymposium on
Venus is occuring this week at Brown University. The
workshops will focus on:
a. The cratering record and models for Venus crustal
resurfacing processes,
b. Volcanic resurfacing processes and styles, and rates of
crustal formation,
c. Scales, styles, and periodicity of mantle convection
and relation to crustal formation and evolution,
d. Chemical differentiation and mantle source region
evolution on Venus,
e. Planetary comparisons: the Lunar highland crust,
f. A discussion of speculations on the thermal and
crustal evolution of Venus.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | People will believe
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | anything if you whisper it.
|_____|/ |_|/ |_____|/ |
Article: 595
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space.news
Subject: Magellan Update - 03/25/92
Date: 26 Mar 92 05:40:25 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from the Magellan Project.
MAGELLAN STATUS REPORT
March 25, 1992
1. Magellan continues to map Venus under the M2080 command
sequence which started March 20. All systems are nominal
and pointing accuracy of the antenna is excellent. The
present mapping passes are from 42 degrees north latitude
to 45 degrees south latitude.
2. Magellan is sending high rate data using the 360 kHz
subcarrier at 115.2 kbps and the signal-to-noise ratio
remains satisfactory.
3. Spacecraft temperatures have warmed slightly, with
Transmitter B now reaching 52.6 degrees C. This is a result of
decreasing periods of solar occultation, i.e. time in the
shadow of Venus. Spacecraft controllers plan to turn off
the radar system heaters to keep the Transmitter B
temperature below 55 degrees C.
4. As reported yesterday, controllers are uplinking changes
to the fault protection this morning. This will assure
that the telecommunication system restarts in its present
configuration in the event of a TWTA (Traveling Wave Tube)
SSO (Spurious Shutoff).
5. Last Friday two global photos were shipped to
investigators; one showing the emissivity of the Venus
surface for 180 degrees of longitude, and the second
showing topography through 360 degrees. A third global
photo, showing surface slope distribution over 360 degrees
will be shipped this week. Only the global emissivity and
reflectivity photo maps remain to be delivered.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | People will believe
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | anything if you whisper it.
|_____|/ |_|/ |_____|/ |
|
| 456.478 | Update - March 25 | VERGA::KLAES | All the Universe, or nothing! | Tue Mar 31 1992 21:05 | 36 |
| Article: 612
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space.news
Subject: Magellan Update #2 - 03/25/92
Date: 28 Mar 92 03:15:44 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from:
PUBLIC INFORMATION OFFICE
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIF. 91109. TELEPHONE (818) 354-5011
MAGELLAN STATUS REPORT
March 25, 1992
The Magellan spacecraft continues to map Venus under a command
sequence which started March 20. All systems work well and pointing
accuracy of the antenna is excellent. The present mapping passes are
from 42 degrees north latitude to 45 degrees south latitude.
Spacecraft temperatures have warmed slightly, with transmitter B
now reaching 52.6 degrees Celsius (126.6 Fahrenheit). That is the
result of decreasing periods of solar occultation, that is, time in
the shadow of Venus. Spacecraft controllers plan to turn off the radar
system heaters to keep the transmitter below 55 degrees C. (131 degrees F.).
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | People will believe
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | anything if you whisper it.
|_____|/ |_|/ |_____|/ |
|
| 456.479 | Updates - March 26 to April 6 | VERGA::KLAES | All the Universe, or nothing! | Wed Apr 08 1992 21:47 | 365 |
| Article: 643
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space.news
Subject: Magellan Update - 03/26/92
Date: 1 Apr 92 08:00:28 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from the Magellan Project.
MAGELLAN STATUS REPORT
March 26, 1992
1. Magellan continues to map the western portion of Aphrodite
Terra on Venus, from 42 degrees north latitude to 45 degrees south.
2. These images provide stereo pairs of the area when coupled
with Cycle 1 coverage and enable scientists to do precise 3 -
dimensional analysis of surface features. The area now being
stereo-mapped is of particular interest for such 3-dimensional
analysis because of vast chasms and ridges.
3. The spacecraft remains nominal. The Transmitter B
temperature has risen slightly, to 52.6 degrees C.
4. Later today, spacecraft controllers will uplink a command to
turn off one of the two radar heaters. The second heater
will be turned off tomorrow.
5. The heaters are not needed now because we are coming out of a
period of solar occultations, that is, when the spacecraft
orbit passes through the shadow of Venus.
6. The time in the shadow of Venus is now less than 50 minutes
per orbit and will diminish rapidly between now and late
Tuesday, when the occultations end.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | People will believe
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | anything if you whisper it.
|_____|/ |_|/ |_____|/ |
Article: 645
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space.news
Subject: Magellan Update - 03/27/92
Date: 1 Apr 92 08:01:47 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from the Magellan Project.
MAGELLAN STATUS REPORT
March 27, 1992
1. Magellan continues to map the Ovda Regio portion of Venus,
from 42 degrees north latitude to 45 degrees south.
2. The spacecraft remains nominal. The Transmitter B
temperature remains at 52.6 degrees C. and the radar is at
33 degrees C.
3. Yesterday, spacecraft controllers turned off one of the
radar system heaters to compensate for a warming trend as
the periods in the shadow of Venus grow shorter. Today
they plan to turn off the remaining radar heater.
4. The heaters are not needed now because we are coming out
of a period of solar occultations, that is, when the
spacecraft orbit passes through the shadow of Venus.
5. The solar occultations are now less than 40 minutes per
orbit and will diminish rapidly between now and late
Tuesday, when the occultations end.
6. Spacecraft controllers are also planning to switch to
1200 bps telemetry and perform some memory readouts to
provide more visibility into the health of various
spacecraft subsystems. This will preclude receiving
science data for one and a half orbits today.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | People will believe
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | anything if you whisper it.
|_____|/ |_|/ |_____|/ |
Article: 646
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space.news
Subject: Magellan Update - 03/31/92
Date: 1 Apr 92 08:04:15 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from the Magellan Project.
MAGELLAN STATUS REPORT
March 31, 1992
1. Magellan continues to map Venus under the M2080 command
sequence . All systems are nominal, temperatures of critical
systems are stable, and all starcals (star calibrations)
yesterday were successful.
2. Magellan continues to send radar image data using the 360 kHz
subcarrier at 115.2 .
3. Abstracts of forty-nine technical papers submitted to the
Journal of Geophysical Research were distributed to Magellan
investigators, staff, and representatives. These papers on
Magellan findings constitute the Magellan Six-Month Report
and are mostly based on Cycle 1 observations.
4. Magellan has now completed 3857 mapping orbits of Venus. Due
to the lower playback rate (115.2 vs 268.8 kbps), each orbit
covers about 50% of the area mapped during the Cycle 1 orbits.
5. At the time Transmitter A failed and we switched to
Transmitter B, it was stated that we would be able to get
only 43% of each mapping swath (115.2 v 268.8 = 42.9%).
6. However, the spacecraft does not travel at a uniform speed
during the mapping pass. By mapping during the portion
closest to periapsis, we can maximize the coverage at about 52%.
7. For example: Cycle 1 full swaths extended from the North Pole
to 78 degrees south latitude (168 degrees). Cycle 3 swaths
extend from 42 north to 45 south (87 degrees). 87 v 168 = 51.8%
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | People will believe
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | anything if you whisper it.
|_____|/ |_|/ |_____|/ |
Article: 680
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space.news
Subject: Magellan Update - 04/01/92
Date: 4 Apr 92 07:11:34 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from the Magellan Project.
MAGELLAN STATUS REPORT
April 1, 1992
1. Magellan continues to map Venus under the M2080 command
sequence which started March 20.
2. On orbit #4522 yesterday morning, the spacecraft performed
an incorrect update during the star calibration and has
missed all starcals during the six orbits since that time.
This has put the Star Data Invalid Counter in to alarm state.
3. Controllers are working to re-establish the correct
attitude reference. This normally involves sending
commands to reset that attitude reference values and
widening the limits for the update from the star calibration.
4. Spacecraft temperatures have continued to climb since the
end of solar occultations 14 hours ago, with Transmitter B
now reaching 55.4 degrees C.
5. Controllers are uplinking changes this morning to offpoint
the solar panels by 45 degrees. This is expected to
stabilize the temperatures within an acceptable range.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | People will believe
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | anything if you whisper it.
|_____|/ |_|/ |_____|/ |
Article: 684
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space.news
Subject: Magellan Update - 04/02/92
Date: 4 Apr 92 07:13:25 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from the Magellan Project.
MAGELLAN STATUS REPORT
April 2, 1992
1. Magellan continues to map Venus under the M2080 command
sequence which started March 20.
2. Yesterday morning, spacecraft controllers successfully
commanded Magellan back to its correct attitude
references. They raised the "Innovation Bound" (the limit
placed on attitude updates) temporarily to 0.2 degree. A
successful Swath 1 starcal was completed on orbit 4529 at
about 10:45 AM PST, and a successful Swath 2 on the next
orbit. The innovation bound was then returned to its
normal value of 0.07 degree.
3. Telemetry indicates that the antenna pointing was never
off by more than 0.25 degree, but this is enough to make
the science data communication marginal. During the seven
orbits of missed starcals (star calibrations), the DSN
(Deep Space Network) stations were shifting in and out of
lock on the high rate signal.
4. Spacecraft temperatures have dropped slightly as a result
of changing the voltage/temperature curve and offpointing
the solar panels by 45 degrees. Transmitter B now reaches
52.6 degrees C. and the battery is at 18.5 degrees C.
5. Later today controllers are uplinking the M2094 command
sequence. Tomorrow they plan to uplink the radar control
parameters and mapping quaternions for a polarimetry test
on Monday.
6. The March 28, 1992 issue of Science News includes two good
articles on Magellan results presented at the Lunar &
Planetary Science Conference in Houston. One reports Jeff
Plaut's findings of possible sand dunes over a 264,000
square kilometer area, based on comparison of Cycle 1 and
Cycle 2 images. The other reports on Russian experiments
to simulate the dark halos which appear around some impact craters.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | People will believe
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | anything if you whisper it.
|_____|/ |_|/ |_____|/ |
Article: 672
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space.news
Subject: Magellan Update - 04/03/92
Date: 4 Apr 92 04:46:30 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from:
PUBLIC INFORMATION OFFICE
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIF. 91109. TELEPHONE (818) 354-5011
MAGELLAN STATUS REPORT
April 3, 1992
The Magellan spacecraft is continuing to map Venus, having
completed 3,879 mapping orbits. This includes 490 orbits of
stereo data in the present eight-month cycle. Stereo imaging
matches current data with images of the same areas obtained in
the first mapping cycle, 16 months ago. So far Magellan has
completed stereo coverage of about 14 percent of the planet, from
42 degrees north to 45 degrees south latitude.
Spacecraft performance is nominal. The period of solar
occultations (when the orbit passes through the shadow of Venus)
ended on Tuesday, and spacecraft temperatures began to rise as
expected. Magellan's controllers corrected for this by changing
the voltage/temperature controls and re-orienting the solar
panels to be 45 degrees from the sun line.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | People will believe
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | anything if you whisper it.
|_____|/ |_|/ |_____|/ |
Article: 682
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space.news
Subject: Magellan Update #2 - 04/03/92
Date: 4 Apr 92 07:14:58 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from the Magellan Project.
MAGELLAN STATUS REPORT
April 3, 1992
1. Magellan continues to map the Ovda Regio portion of Venus,
from 42 degrees north latitude to 45 degrees south.
2. The spacecraft remains nominal. All starcals (star
calibrations) since yesterday were successful except two
which were partially successful with one missed star.
3. The Transmitter B temperature is now down to 51.9 degrees
C and the TWTA (Traveling Wave Tube) is at 57-58 degrees C.
4. The M2094 command sequence will go into effect this
morning. This sequence will be very much like the last
two, except the spacecraft will perform a 5-orbit
polarimetry test on Monday afternoon. The radar mapping
parameters for the test are scheduled to be uplinked later
today, with contingency command windows on Sunday and Monday.
5. Magellan is now almost a third of the way through Cycle 3.
In spite of problems with the on-board transmitter which
reduced the playback data rate, we have obtain stereo
coverage of about 14% of the Venus surface.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | People will believe
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | anything if you whisper it.
|_____|/ |_|/ |_____|/ |
Article: 706
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space.news
Subject: Magellan Update - 04/06/92
Date: 8 Apr 92 04:09:27 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from the Magellan project.
MAGELLAN STATUS REPORT
April 6, 1992
1. Magellan continues to map Venus under the M2094 command
sequence which started Friday. All systems are nominal
and pointing accuracy of the antenna is excellent. Only
one star calibration was missed over the weekend.
2. Magellan is sending radar image data using the 360 kHz
subcarrier at 115.2.
3. The spacecraft temperatures are remaining stable, with
Transmsitter B now at 51.2 degrees C with a cycle depth
of q2 degrees.
4. Early this afternoon the spacecraft will perform a 5-orbit
polarimetry test. The radar mapping parameters for the
test were uplinked Friday. While the test is in progress,
new radar parameters will be uplinked to return the
spacecraft to normal, left-looking radar mapping at the
end of the polarimetry test about 3:40 pm tomorrow.
5. Magellan is now over a third of the way through Cycle 3.
In spite of problems with the on-board transmitter which
reduced the playback data rate, we have obtain stereo
coverage of about 14% of the Venus surface and may reach
35 to 40% by the end of Cycle 3.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | People will believe
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | anything if you whisper it.
|_____|/ |_|/ |_____|/ |
|
| 456.480 | Update - April 8 | VERGA::KLAES | All the Universe, or nothing! | Fri Apr 10 1992 19:49 | 45 |
| Article: 718
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space.news
Subject: Magellan Update - 04/08/92
Date: 9 Apr 92 07:00:06 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from:
PUBLIC INFORMATION OFFICE
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIF. 91109. TELEPHONE (818) 354-5011
MAGELLAN STATUS REPORT
April 8, 1992
Magellan continues to map Venus under a command sequence sent to
the spacecraft April 3. All systems are working well and pointing
accuracy of the antenna is excellent.
Superior conjunction begins June 14 and as it approaches there
will be a need for increased use of the High Efficiency (HEF) Deep
Space Network stations and 70-meter antennas, but the need will have
to be balanced with other DSN tracking commitments. As during cycle
1, there will be a point prior to June 14 when communications cannot
be maintained because the sun will be between Earth and Venus and
there will be another "superior conjunction gap".
Spacecraft temperatures remain stable with the transmitter now at
51.2 C (124 F). The present geometry causes the solar panels to do an
180 degree shift as the spacecraft goes from mapping to playback. This
has accelerated the solar array drive mechanism "slip," an
accumulating difference between the array position as indicated by the
stepper motors and the onboard computer reference. At the present slip
rate, a correction command will be needed before the weekend.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | People will believe
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | anything if you whisper it.
|_____|/ |_|/ |_____|/ |
|
| 456.481 | Updates - April 8-16 | VERGA::KLAES | All the Universe, or nothing! | Fri Apr 17 1992 19:16 | 323 |
| Article: 791
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space.news
Subject: Magellan Update - 04/08/92
Date: 15 Apr 92 05:38:16 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from the Magellan Project
MAGELLAN STATUS REPORT
April 8, 1992
1. Magellan continues to map Venus under the M2094 command
sequence which started Friday, April 3rd. All systems are
nominal and pointing accuracy of the antenna is excellent.
2. Magellan is sending radar image data using the 360 kHz
subcarrier at 115.2 kbps. The signal-to-noise ratio at
the standard DSN (Deep Space Network) stations is varying
between -1 and -3 db (which is probably too low for satisfactory
images), but reception at the High Efficiency (HEF) DSN stations
has an SNR between 0 and +1 db.
3. As we approach Superior Conjunction on June 14, increased
use of the HEF and 70 meter antennas is desirable, but has
to be balanced with other DSN tracking commitments. As
during Cycle 1, we will reach a point prior to June 14
when communications cannot be maintained, causing another
"Superior Conjunction Gap."
4. The spacecraft temperatures are remaining stable, with
Transmsitter B now at 51.2 degrees C with a cycle depth of
q 2 degrees. Following yesterday's 8-orbit polarimetry test, in
which the spacecraft rolled 90 degrees, temperatures returned to
what they were before the test.
5. The present geometry causes the solar panels to do an 180
degree shift as the spacecraft goes from mapping to
playback. This has accelerated the Solar Array Drive
Mechanism (SADM) "slip," an accumulating difference
between the array position as indicated by the stepper
motors vs the on-board computer reference.
6. This is corrected by commands to reset the referenced
position. At the present slip rate, a correction will be
needed before this weekend.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | People will believe
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | anything if you whisper it.
|_____|/ |_|/ |_____|/ |
Article: 794
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space.news
Subject: Magellan Update - 04/09/92
Date: 15 Apr 92 05:39:32 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from the Magellan Project.
MAGELLAN STATUS REPORT
April 9, 1992
1. Magellan continues to map Venus under the M2094 command
sequence which started April 3. All systems are nominal
and all starcals (star calibrations) yesterday were successful.
2. Spacecraft temperatures have dropped slightly, with
Transmitter B now at 50.5 degrees C., but are expected to
begin rising again as we approach the end of the present
command sequence during the coming week.
3. Controllers are proposing to switch the telemetry to 1200
bps during orbit 4588 this morning in order to better
characterize the performance of the Radio Frequency
Subsystem (specifically Transmitter B) in relation to the
present temperature cycle
4. This will cause the loss of science data for at least one
orbit, but the SNR has been from -.5 to -3 db even over the
DSN (Deep Space Network) HEF (High Efficiency) stations, so it
is more important to work on improving the communications than
to collect more marginal data.
5. Reports from Washington included the good news that the
House Appropriations Committee included $10M for FY93
Magellan operations in the NASA funding bill which it plans
to present for House approval.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | People will believe
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | anything if you whisper it.
|_____|/ |_|/ |_____|/ |
Article: 729
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space.news
Subject: Magellan Update - 04/10/92
Date: 11 Apr 92 05:53:01 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Fowarded from the Magellan Project.
MAGELLAN STATUS REPORT
April 10, 1992
1. Magellan continues to map Venus under the M2094 command
sequence including the bi-weekly psuedo tweak uplinked
yesterday. All systems are nominal and all starcals
(star calibrations) yesterday were successful.
2. Spacecraft temperatures have dropped slightly again, with
Transmitter B now at 50 degrees C. The Transmitter B
performance for controlling x-band modulation continues
to be very sensitive to temperature and temperature changes.
3. A test ran yesterday by switching to 1200 bps engineering
telemetry during orbit 4588, show that the character of
the spurious radio system signal spur is very dependant on
Transmitter B temperature. An additional test is being
performed today on orbit 4596 during which time the radio
spectrum will be video recorded for further analysis.
4. Science radar data acquisition continues to be marginally
acceptable over DSN (Deep Space Network) 34 meter HEF
(High Efficiency) stations and very poor over DSN
34 meter standard stations. Additional station coverage
upgrades are being planned in coming months, with the
addition of array passes, and a few DSN 70 meter stations
for special tests.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | People will believe
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | anything if you whisper it.
|_____|/ |_|/ |_____|/ |
Article: 793
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space.news
Subject: Magellan Update - 04/13/92
Date: 15 Apr 92 05:40:51 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from the Magellan Project.
MAGELLAN STATUS REPORT
April 13, 1992
1. Magellan continues to map Venus under the M2094 command
sequence which started ten days ago. All systems are
nominal and pointing accuracy of the antenna is excellent.
2. Magellan is sending radar image data using the 360 kHz
subcarrier at 115.2 kbps, but most science data received
over the weekend is not usable.
3. Most DSN (Deep Space Network) tracking has been over the 34
meter stations, but 70 meter stations may be required to get
usable science data. SNR's over the 34 meter stations are
ranging from -1 to -4 db for the 115.2 kbps rate.
4. On Friday spacecraft controllers switched the engineering
telemetry to 1200 bps for one orbit, then switched to
carrier only, in order to further characterize the
performance of the transmitter in its present temperature
environment. The data obtained in this test and the
weekend performance indicates that Transmitter B's X-band
performance is continuing to degrade.
5. The spacecraft temperatures are remaining stable, with
Transmsitter B now at 51.2 degrees C with a cycle depth of q 2 degrees.
6. Magellan is now 37% of the way through Cycle 3.
7. On Friday, several present and former Magellan managers,
attended a banquet in Washington, D.C., where the project was
awarded the Robert Goddard Memorial Trophy.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | People will believe
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | anything if you whisper it.
|_____|/ |_|/ |_____|/ |
Article: 792
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space.news
Subject: Magellan Update - 04/14/92
Date: 15 Apr 92 05:42:37 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from the Magellan Project
MAGELLAN STATUS REPORT
April 14, 1992
1. Magellan continues to map Venus under the M2094 command
sequence . All systems are nominal, temperatures of critical
systems are stable, and all starcals (star calibrations)
yesterday were successful.
2. Magellan is sending radar image data using the 360 kHz
subcarrier at 115.2 kbps, but most science data received over
by the 34 meter DSN (Deep Space Network) stations is not usable.
3. Today spacecraft controllers will be sending updates to the
Kalman gains and reference star pair in preparation for
Thursday's uplink of the M2108 command sequence. The new
command sequence will go active on Friday, and will include
gravity data collection on every eighth orbit starting April 22nd.
4. During last week's festivities in Washington, when Magellan
was honored with the Goddard trophy, Dr. Steve Saunders also
gave a science briefing for NASA Headquarters, emphasizing
the recent results and potential studies in future cycles.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | People will believe
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | anything if you whisper it.
|_____|/ |_|/ |_____|/ |
Article: 807
Newsgroups: sci.space.news
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Subject: Magellan Update - 04/15/92
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Date: Fri, 17 Apr 1992 06:42:45 GMT
Forwarded from the Magellan Project
MAGELLAN STATUS REPORT
April 15, 1992
1. Magellan continues to map Venus under the M2094 command
sequence which started Friday, April 3rd. All systems are
nominal and pointing accuracy of the antenna is excellent.
The spacecraft temperatures are remaining stable.
2. Magellan is sending radar image data using the 360 kHz
subcarrier at 115.2 kbps. The signal-to-noise ratio at
the DSN (Deep Space Network) stations is varying between
0 and -3 db.
3. As we approach Superior Conjunction on June 14, increased
use of the 70 meter antennas is desirable, but may only be
possible for targetted areas. As during Cycle 1, we will
reach a point prior to June 14 when com-munications cannot
be maintained, causing another "Superior Conjunction Gap."
4. The Solar Array Drive Mechanism (SADM) "slip," an
accumulating difference between the array position as
indicated by the stepper motors vs the on-board computer
reference, will be corrected by ground commands tomorrow..
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Denial is always the first
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | sympton.
|_____|/ |_|/ |_____|/ |
Article: 808
Newsgroups: sci.space.news
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Subject: Magellan Update - 04/16/92
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Date: Fri, 17 Apr 1992 06:44:04 GMT
Forwarded from the Magellan Project
MAGELLAN STATUS REPORT
April 16, 1992
1. Magellan continues to map Venus under the M2094 command
sequence which started April 3. All systems are nominal
and all starcals (star calibrations) yesterday were successful.
2. Spacecraft temperatures are warming slightly, although
Transmitter B remains at 50.5 degrees C.
3. The spacecraft experienced a spurious shutoff (SSO) of
TWTA-A (Traveling Wave Tube Amplifier) this morning at
about 7:19 AM PDT. Controllers were already planning
to switch to TWTA-B today. If the performance is satisfactory,
the fault protection will be reconfigured to bring up this
TWTA and the 360 kHz subcarrier at 115.2 kbps in the event
of another SSO.
4. The slip in the Solar Array Drive Mechanism has remained
at -6.8 degrees for several days, so the update to the
commanded position has been postponed to next week.
5. The M2108 command sequence is scheduled to be uplinked
late today and begin execution mid-morning tomorrow. This
sequence is similar to the present one, with mapping from
42 degrees north to 45 degrees south latitude, but
includes gravity data collection on every eighth orbit
starting Wednesday, April 22nd.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Denial is always the first
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | sympton.
|_____|/ |_|/ |_____|/ |
|
| 456.482 | Updates - April 19-24 | VERGA::KLAES | All the Universe, or nothing! | Sat Apr 25 1992 20:29 | 471 |
| Article: 824
Newsgroups: sci.space.news
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Subject: Magellan Atlas Program
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Date: Mon, 20 Apr 1992 08:22:41 GMT
MAGELLAN ATLAS PROGRAM
April 19, 1992
An updated version of the Magellan Atlas program has been released by the
Magellan project. This program was designed to be used with the Magellan
CDROMs. This program will do the following (new features denoted by *):
o find the latitude/longitude of named features on Venus
o given a latitude/longitude, find the mosaics which lie atop
that point and the CDROMs on which they are found.
*o the atlas now includes CDROMs up through 69
*o the named feature descriptions now includes a short description
of the meaning (origin) of the name
*o find all the named features which lie in (or on) a specific mosaic
has been added, in order to help those who wish to work with a
specific CD-ROM or mosaic. (This should be helpful to teachers, who
may have only a limited set of CD-ROMs.)
There is both an IBM PC and Macintosh version of the Magellan Atlas
program. The programs are available using anonymous ftp at:
ftp: ames.arc.nasa.gov (128.102.18.3)
user: anonymous
cd: pub/SPACE/SOFTWARE
files: magellan.zip (IBM PC version -> PKZIP)
magellan.sit (Macintosh version -> Stuffit, MacBinary format)
Also, the database for the Magellan Atlas is available in ASCII format.
A description of each field is included at the beginning of each file.
The database files are available at:
ftp: ames.arc.nasa.gov (128.102.18.3)
user: anonymous
cd: pub/SPACE/MAGELLAN
files: names.txt
midr.txt
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Denial is always the first
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | sympton.
|_____|/ |_|/ |_____|/ |
Article: 831
Newsgroups: sci.space.news
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Subject: Magellan Update - 04/20/92
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Date: Tue, 21 Apr 1992 02:39:10 GMT
Forwarded from the Magellan Project
MAGELLAN STATUS REPORT
April 20, 1992
1. Magellan continues to map Venus under the M2108 command
sequence which started Friday. All systems are nominal
and pointing accuracy of the antenna is excellent.
2. After the start of the M2108 sequence on Friday,
spacecraft temperatures unexpectedly dropped a couple of
degrees, with Transmsitter B now varying between 48-49
degrees C. This has had a degrading effect on communications,
which were already marginal due to the noise spur in the
Transmitter and the increasing distance to earth.
3. On Friday controllers switched on the radar heaters to
raise the temps, and are considering switching the command
receivers. At the moment, the 360 kHz subcarrier has been
turned off and no science data is being received.
4. Starting this Wednesday, the spacecraft will operate in a
gravity data collection mode on every eight orbit.
Instead of turning to map the surface of Venus as it
approaches periapsis, Magellan will remain pointed at
earth. This will allow the DSN (Deep Space Network)
stations to collect very precise tracking data.
5. This data allows scientists to look for the subtle effects
of gravitational anomalies on the orbit of Magellan. For
this purpose we need only a good carrier signal, so the
present transmitter modulation (on TX-A) and noise spur
problems will not prevent the gravity data collection.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Denial is always the first
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | sympton.
|_____|/ |_|/ |_____|/ |
Article: 833
Newsgroups: sci.space.news
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Subject: Magellan Press Conference
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Date: Wed, 22 Apr 1992 02:04:08 GMT
Forwarded from:
PUBLIC INFORMATION OFFICE
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIF. 91109. TELEPHONE (818) 354-5011
EDITOR'S ADVISORY
Magellan News Conference
Wednesday, April 22, 1992
The Magellan Project will hold a news conference Wednesday,
April 22, at 10 a.m. PDT at the Jet Propulsion Laboratory's von
Karman Auditorium. Theme of the conference will be "The Mountains
and Volcanoes of Venus."
New stereo images will be shown, and on April 22, Magellan
begins to collect gravity data for the first time; the importance
of gravity data will be discussed.
Separate 10-minute presentations will be given by
Project Manager Jim Scott; Project Scientist Steve Saunders; and
science team members Drs. Gordon Pettengill and Jim Head. Martin-
Marietta spacecraft team representative Julie Webster will be
available for questions.
Four images will be released including side-by-side images.
Large differences are seen between Cycle 1 and Cycle 2 images and
the science team members are assessing possible causes.
The news conference will be carried over NASA Select television.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Denial is always the first
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | symptom.
|_____|/ |_|/ |_____|/ |
Article: 834
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space.news
Subject: Magellan Update - 04/21/92
Date: 22 Apr 92 04:07:02 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from the Magellan Project
MAGELLAN STATUS REPORT
April 21, 1992
1. Magellan continues to orbit Venus under the M2108 command
sequence . All systems are nominal, temperatures of
critical systems are stable, and all starcals (star
calibrations) yesterday were successful.
2. The high rate subcarrier has been turned off since Friday,
when the temperature of Transmitter B dropped unexpectedly
to 44 degrees C. The transmitter performance was degraded
such that no science data was being received.
3. On Saturday the radar heaters were turned on and raised
the Transmitter temp to 49.2 degrees C. There was some
increase in performance, but not enought to permit a
return to mapping.
4. A change in the mapping control parameters, which will
roll the spacecraft 90 degrees about the High Gain Antenna
and raise the transmitter temperature another 3 degrees,
is planned for today. This is expected to return Magellan
to radar mapping by tomorrow.
5. Starting with orbit 4683 at 8:36 AM PDT tomorrow, we will
begin collecting gravity data on every eighth orbit.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Denial is always the first
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | symptom.
|_____|/ |_|/ |_____|/ |
Article: 835
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space.news
Subject: Space Science News Briefings
Date: 22 Apr 92 07:24:21 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Paula Cleggett-Haleim
NASA Headquarters, Washington, D.C. April 21, 1992
(Phone: 202/453-1547)
NOTE TO EDITORS: N92-31
SPACE SCIENCE NEWS BRIEFINGS
MAGELLAN
The mountains and volcanoes of Venus will be the subject of a
Magellan briefing, originating from the Jet Propulsion Laboratory,
Pasadena, Calif., Wednesday April 22, 1:00 pm EDT. Media can
monitor the briefing from the NASA auditorium, 400 Maryland
Avenue, S.W. Washington, D.C.
Participants will include Jim Scott, project manager; Julie
Webster, Martin-Marietta spacecraft team representative; Steve
Saunders, project scientist; and Drs. Gordon Pettengill and Jim
Head, science team members.
This event will be carried live on NASA Select Television
(Satcom F-2R, Transponder 13, 72 degrees West longitude, frequency
3960.0 MHz, audio 6.8 MHz). Questions will be entertained from
reporters at Headquarters and at NASA Centers.
EDITOR'S NOTE: Four Magellan images are available to
illustrate this story, through NASA's audio visual branch: 92-H-
241; 92-H-242; 92-H-243; 92-H-244.
COSMIC BACKGROUND EXPLORER
Scientists will present new information from the Cosmic
Background Explorer at 12:00 noon Thursday, April 23, at the
American Physical Society meetings, held at the Ramada Renaissance
Techworld, in Washington, D.C. The media briefing will be held in
room 6 of the hotel/office complex, which is located at 999 9th
Street N.W.
Participants will include members of the Differential
Microwave Radiometer (DMR) team. The DMR instrument was designed
to search for temperature variations across the sky of the relic
cosmic microwave background radiation from the Big Bang.
EDITOR'S NOTE: An artist's concept depicting crucial periods
in the development of the universe and a map of the sky taken by
COBE's DMR are available at the American Physical Society meetings
and through NASA's audio/visual branch, on Thursday April 23.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Denial is always the first
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | symptom.
|_____|/ |_|/ |_____|/ |
Article: 836
Newsgroups: sci.space.news
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Subject: Magellan Caption Files
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Date: Wed, 22 Apr 1992 08:17:32 GMT
==========================
MAGELLAN CAPTION FILES
April 21, 1992
==========================
An updated version of the caption files for the Magellan images is now
available. These caption files are the detailed descriptive text that goes
along with each of the public released Venus images taken by the Magellan
spacecraft. The caption files are provided in four formats: ASCII format,
IBM Wordperfect 5.1 format, IBM Word format, and a Macintosh Word format
compressed with the Stuffit program (MacBinary format). The files are
available using anonymous ftp at:
ftp: ames.arc.nasa.gov (128.102.18.3)
user: anonymous
cd: pub/SPACE/MAGELLAN
files: captions.txt (ASCII)
capswp5.zip (IBM PC Wordperfect 5.1 -> PKZIP)
capswrd.zip (IBM PC Word -> PKZIP)
captions.sit (Macintosh Word -> Stuffit)
Each caption is identified by a P number. With this P number you can
order the corresponding lithograph photograph from the National Space Science
Data Center.
National Space Science Data Center
Goddard Space Flight Center
Greenbelt, Maryland 20771
Telephone: (301) 286-6695
Email address: request@nssdca.gsfc.nasa.gov
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Denial is always the first
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | symptom.
|_____|/ |_|/ |_____|/ |
Article: 839
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space.news
Subject: Magellan Update - 04/22/92
Date: 23 Apr 92 04:37:25 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from the Magellan Project
MAGELLAN STATUS REPORT
April 22, 1992
1. Magellan continues to orbit Venus under the M2108 command
sequence . The spacecraft is operating in a carrier-only, 40 bps
engineering telemetry mode.
2. Since yesterday the spacecraft has also experienced a number
of spurious interrupts during star calibration maneuvers. Both
stars were missed on Orbit 4680, and one star was missed on
several other orbits. The star invalid counter stands at four,
with an alarm limit of six. However, no bad updates to the
attitude control have occurred.
3. The temperature of Transmitter B has risen slightly since the
spacecraft was rolled -90 degrees late yesterday, but the
performance still does not permit switching on the 360 kHz
subcarrier with science data.
4. Yesterday commands were sent to turn on the 960 kHz
subcarrier, then the 360 kHz subcarrier, followed by X-band
engineering telemetry at 1200 bps. These tests were to permit
further characterization of the communications at Transmitter B
warms up.
5. Starting with orbit 4683 at 8:36 AM PDT today, Magellan will
switch to 1200 bps X-band engineering telemetry on every eighth
orbit, as we will begin collecting gravity data.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Denial is always the first
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | symptom.
|_____|/ |_|/ |_____|/ |
Article: 843
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space.news
Subject: Magellan Update - 04/23/92
Date: 24 Apr 92 05:28:02 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from the Magellan Project
MAGELLAN STATUS REPORT
April 23, 1992
1. Magellan continues to orbit Venus under the M2108 command
sequence . The spacecraft is sending science data at 115.2 kbps
using the 360 kHz subcarrier, plus the 40 bps X-band engineering
telemetry data.
2. All starcals (star calibrations) since yesterday have been successful,
with only one missed star. The filter activity (when the attitude control
computer rejects spurious readings from the star tracker) has
diminished, and the attitude updates are in the expected range.
3. The temperature of Transmitter B has risen slightly and is
now at 51.5 degrees C.
4. Following the first gravity data collection orbit yesterday
morning, the on-board sequence automatically turned on the 360
kHz subcarrier and switched from 1200 bps engineering data to 40
bps. However, the signal-to-noise ratio (SNR) is still too
low to receive usable science data.
5. This sequence will continue on every eighth orbit for the
next two and a half weeks. At the start of a gravity data
collection orbit the subcarrier is switched off and the
engineering telemetry is set to 1200 bps. On the next seven
orbits, Magellan performs a normal mapping pass and sends the
data on the 360 kHz subcarrier at 115.2 kbs. The engineering
telemetry is automatically switched to 40 bps.
6. Later today, controllers are planning to uplink mapping
parameters which will roll the spacecraft 180 degrees and
switch from Receiver A to Receiver B. The actual swap of
receivers will occur tomorrow morning. This is expected to
produce some slight warming of Transmitter B.
7. Yesterday, Jim Scott, Steve Saunders, Gordon Pettengill, Jim
Head and Julie Webster participated in a Magellan press
conference in which recent results of our Venus observations were
presented along with a new "over-flight" video of Maat Mons and
Sapas Mons, two shield volcanos in Alta Regio.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Denial is always the first
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | symptom.
|_____|/ |_|/ |_____|/ |
Article: 848
Newsgroups: sci.space.news
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Subject: Magellan Update - 04/24/92
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Date: Sat, 25 Apr 1992 05:53:39 GMT
Forwared from the Magellan Project
MAGELLAN STATUS REPORT
April 24, 1992
1. Magellan continues to orbit Venus under the M2108 command
sequence . All starcals (star calibrations) since yesterday
have been successful, with nominal attitude updates. The filter
activity remains low.
2. Yesterday a series of commands were sent, the first to
perform a test on tape recorder A (DMS-A) and the rest
aimed at raising the temperature of Transmitter B by about
2 degrees C.
3. Preliminary results from the DMS-A test indicate its
performance is unchanged.
4. The actions associated with raising the temperature of
Transmitter B included a 180 degree roll and a switch from
Receiver A to Receiver B. Following the roll, temps
dropped to 48 degrees C., and the SNR ranged from -1 to -9 dn.
5. The switch to Receiver B brought the temps back up 3 to 4
degrees. The SNR has improved - presently the SNR of the
1200 bps engineering data went from zero to +7.5 dn
6. Controllers are now planning to turn on the 360 kHz
subcarrier for the second playback this morning at about
10:30 AM PDT. This is followed by a gravity data
collection orbit. Then, the on-board sequence will
automatically return to the 360 kHz subcarrier with 115.2
kbps science data and 40 bps engineering data. .
7. The performance of Transmitter B during this week
indicates that we have to operate in a narrow temperature
band in the low 50's. If we get too much above 55, we
risk destroying a critical component and losing the
transmitter. When we allow the temps to drop below 50,
the signal spur wipes out all usable data.
8. Transmitter A, which lost its subcarrier modulation in
January, is still usable for the gravity data collection
planned for Cycle 4.
9. Preliminary analysis of doppler data collected during the
gravity orbit indicates higher than anticipated noise,
likely caused by increased sun activity.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Denial is always the first
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | symptom.
|_____|/ |_|/ |_____|/ |
|
| 456.483 | Updates - April 27 to May 1 | VERGA::KLAES | All the Universe, or nothing! | Fri May 01 1992 21:51 | 227 |
| Article: 856
Newsgroups: sci.space.news
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Subject: Magellan Update - 04/27/92
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Date: Tue, 28 Apr 1992 04:36:37 GMT
Forwarded from the Magellan Project
MAGELLAN STATUS REPORT
April 27, 1992
1. Magellan continues to map Venus under the M2108 command sequence
which started ten days ago. However, communication of high rate science
data continues to be marginal or poor.
2. There were seven partially successful starcals (star calibration) and
one failed starcal over the weekend, but the antenna pointing remains precise.
3. The temperature of Transmitter B peaks at 51.9 degrees C during mapping
orbits, and 53.3 degrees during gravity orbits, but the SNR on the high rate
(115.2 kbps) data is running from -2 to -3 db.
4. A "pseudo-tweak," the routine weekly update to radar control parameters, is
scheduled for later today.
5. A Science Briefing for Magellan team members in Denver is being given
today. Tomorrow, there will be a Technical Interchange Meeting to discuss
spacecraft performance and options for continued operations.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Denial is always the first
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | symptom.
|_____|/ |_|/ |_____|/ |
Article: 862
Newsgroups: sci.space.news
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Subject: Magellan Update - 04/29/92
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Date: Thu, 30 Apr 1992 02:55:20 GMT
Forwarded from the Magellan Project
MAGELLAN STATUS REPORT
April 29, 1992
1. Magellan continues to map Venus under the M2108 command
sequence. Communication of high rate science
data, however, continues to be marginal or poor.
2. There were four partially successful starcals (star calibratons)
yesterday. The other three starcals were successful.
3. The temperature of Transmitter B varies between at 52.6
and 53.3 degrees C during mapping orbits, and peaks at 54
degrees during gravity orbits.
4. The DSN (Deep Space Network) stations succeeded in occasionally
locking up to the high rate science data yesterday, but the SNR
is -1.3 db at best. Previous analysis by the Radar System
Engineering Team indicates that we need an SNR of -.5 db
or better to obtain usable radar images.
5. Today controllers are uplinking some changes to the
battery fault protection thresholds and will send up the
M2122 command sequence later today.
6. Yesterday, Kenny Starnes of Martin-Marietta gave a noon-
time talk in von Karman on Magellan's use of the flight
spare Galileo CDS (Command Data Subsystem) hardware and software.
7. Thirteen months of Magellan CD-ROM development was
completed with the distribution of ten ARCDR-CD's
(Altimetry-Radiometry Composite Data Record - Compact
Disks) and one GxDR-CD (Global Altimetry/Radiometry Data
Record Compact Disk) to the Magellan investigators.
8. In addition, four more MIDRCD's (Mosaicked Image Data Record
Compact Disks - No.s 49-52) were distributed to the investigators.
9. It is expected that all of the CD-ROM's will be approved
for distribution to the science community at the Data
Products Working Group and Project Science Group meetings
on 18-20 May 1992, with actual distribution in mid-June 1992.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Denial is always the first
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | symptom.
|_____|/ |_|/ |_____|/ |
Article: 870
Newsgroups: sci.space.news
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Subject: Magellan Update - 04/30/92
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Date: Fri, 1 May 1992 02:27:30 GMT
Forwarded from the Magellan Project
MAGELLAN STATUS REPORT
April 30, 1992
1. Magellan continues to orbit Venus under the M2108 command
sequence . The spacecraft is sending science data at
115.2 kbps using the 360 kHz subcarrier, plus the 40 bps
X-band engineering telemetry data.
2. All starcals (star calibrations) since yesterday have been
successful, with only one missed star. The attitude updates
are in the expected range.
3. The temperature of Transmitter B is steady at 52.6 to 53.3
degrees C, and although it is in the range desired by the
spacecraft engineers, the SNR on the high rate signal is
still -1.3 db. At this level, science data quality is questionable.
4. Additional test are being conducted by the project,
Division 33 personnel, and the Deep Space Network to determine
if other methods of handling the corrupted Magellan
spacecraft radio signal with ground station equipment are
feasible. These tests are being performed at Goldstone
today and Friday.
5. The Spacecraft Team is also weighing various options,
including turning off the transmitter and allowing it to
cool down to about 30 degrees, to analyze its performance
as it warms up. It's performance in this mode last
January was satisfactory.
6. If this was determined to be the only operating mode, it
would further limit the amount of radar image data which
could be collected and transmitted to earth.
7. Magellan has completed seven gravity data collection
orbits since last week, these orbits are interleaved on
every eighth orbit with radar data collection. Preliminary
checks of the gravity data indicate excellent performance.
8. Later today, controllers are planning to uplink the M2122
command sequence, which will continue the present mode of
interleaved radar and gravity data collection. The radar
mapping swaths are from 42 degrees north to 45 degrees
south latitude.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Denial is always the first
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | symptom.
|_____|/ |_|/ |_____|/ |
Article: 909
Newsgroups: sci.space.news
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Subject: Magellan Update - 05/01/92
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Date: Sat, 2 May 1992 04:58:07 GMT
Forwarded from the Magellan Project
MAGELLAN STATUS REPORT
May 1, 1992
1. Magellan continues to orbit Venus and began execution of
the M2122 command sequence at 9:54 AM PDT today. All
starcals (star calibrations) since yesterday have been
successful, with only one missed star.
2. The temperature of Transmitter B is steady at 52.6 to 54
degrees C, and although it is in the range desired by the
spacecraft engineers, the SNR on the high rate signal is
still -1.5 db. Earlier tests by the Radar System
Engineering Team show that science data at such a low
level is unusable.
3. Yesterday and today, tests are being conducted by the
project, Division 33 personnel, and the Deep Space Network
to determine if other methods of handling the corrupted
Magellan spacecraft radio signal with ground station
equipment are feasible. Tests performed at Goldstone
yesterday gave a preliminary indication that positive SNRs
can be achieved.
4. Magellan has completed eight gravity data collection
orbits since last week. These orbits are interleaved on
every eighth orbit with radar data collection.
Preliminary checks of the gravity data indicate excellent
performance.
5. On the gravity orbits the spacecraft remains pointed at
the Earth during the periapsis portion of the orbit. This
allows the precise measurement of doppler shifts caused by
variations in the density of Venus. After extracting
orbital changes caused by other forces such as solar wind,
the doppler residuals can be mapped to reveal
concentrations of mass in the planet.
6. Transmitter A, which lost its subcarrier modulation in
January, is still usable for the gravity data collection
planned for Cycle 4 in the event Transmitter B can no
longer return usable radar data.
7. Magellan has now completed 4084 mapping orbits of Venus,
794 orbits (45%) of Cycle 3. We have achieved stereo
mapping of about 15% of the surface.
8. We have not added to the 97% total coverage because the
unmapped areas are either outside the latitudes being
covered now or will not be in view of Magellan until the
last weeks of Cycle 3 in September.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Denial is always the first
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | symptom.
|_____|/ |_|/ |_____|/ |
|
| 456.484 | Updates - May 4-6 | VERGA::KLAES | All the Universe, or nothing! | Thu May 07 1992 22:00 | 138 |
| Article: 921
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space.news
Subject: Magellan Update - 05/04/92
Date: 5 May 92 07:02:43 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from:
MAGELLAN STATUS REPORT
May 4, 1992
1. Magellan continues to map Venus under the M2122 command
sequence which started Friday. All systems are nominal
and high rate science data is being successfully received.
2. There were six partially successful starcals (star calibrations)
out of the 22 performed over the weekend, and the attitude control
remains precise.
3. The communication tests performed at Goldstone on Thursday
and Friday produced a 3 db improvement in the signal-to-
noise ratio (SNR) of the high rate data. The SNR is
presently running 1.5 to 2 db.
4. This improvement was accomplished by making a baseband
phase adjustment. Plans to implement this change at the
other DSN (Deep Space Network) stations are presently being pursued.
5. The Science Support Team reported on Friday that, except
for a few orbits after the TWTA (Traveling Wave Tube
Amplifier) swap on April 16, the science data from the last
175 orbits appears unusable due to the degraded performance
of Transmitter B.
6. However, now that a correction to the communication
problems has been found, the Project expects to collect
good science data for the remainder of Cycle 3 except for
the 20 day Superior Conjunction gap around June 14, 1992.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Denial is always the first
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | symptom.
|_____|/ |_|/ |_____|/ |
Article: 932
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space.news
Subject: Magellan Update - 05/05/92
Date: 6 May 92 08:19:57 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from the Magellan Project
MAGELLAN STATUS REPORT
May 5, 1992
1. Magellan continues to collect radar and gravity data at
Venus under the M2122 command sequence. All systems are
nominal and all starcals (star calibrations) were successful,
with only one missed star.
2. The Solar Array Drive Mechanism (SADM) slip has remained
unchanged for most of the past week.
3. The temperature of Transmitter B peaks at 52.6 degrees C
during mapping orbits. This has remained steady for the past week.
4. The base band phase adjustment has been implemented at the
DSN (Deep Space Network) stations, with mixed results. The
SNR at standard stations remains low, at about -1.5 db, while
the High Efficiency (HEF) stations have achieved positive SNR's
of 1.5 to 2 db.
5. As the mission approaches Superior Conjunction (when Venus
and Earth are on opposite sides of the sun) on June 14,
the SNR was predicted to lose about .5 db during the next three weeks.
6. As the path of the radio signal passes deeper into the
solar corona, X-band communications will become too noisy
to maintain lock on the signal. The predicted Superior
Conjunction gap is from June 4 thru June 24.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Denial is always the first
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | symptom.
|_____|/ |_|/ |_____|/ |
Article: 942
Newsgroups: sci.space.news
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Subject: Magellan Update - 05/06/92
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Date: Thu, 7 May 1992 05:55:09 GMT
Forwarded from the Magellan Project
MAGELLAN STATUS REPORT
May 6, 1992
1. Magellan continues to collect radar and gravity data at
Venus under the M2122 command sequence. All systems are
nominal and essentially unchanged since yesterday.
2. The temperature of Transmitter B peaks at 52.6 degrees C
during mapping orbits, and 53.3 deg. during each gravity
orbit. This reflects a very slight cooling trend.
3. As reported yesterday, the base band phase adjustment at
the DSN (Deep Space Network) High Efficiency (HEF) stations
have achieved positive SNR's of 1.5 to 2 db. This brings
the high rate data into the range where usable images can
be produced.
4. However, some of the Magellan tracking passes are over
standard DSN stations and, although some improvement in
communications was seen at these stations, the SNR remains
too low for receiving usable radar data.
5. Magellan continues to perform left-look radar mapping
passes from 42 deg. north latitude to 45 deg. south on
seven consecutive orbits, then keeps the high gain antenna
pointed to Earth during the eighth orbit to provide gravity data.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Denial is always the first
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | symptom.
|_____|/ |_|/ |_____|/ |
|
| 456.485 | Updates - May 7-13 | VERGA::KLAES | All the Universe, or nothing! | Wed May 13 1992 21:45 | 220 |
| Article: 947
Newsgroups: sci.space.news
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Subject: Magellan Update - 05/07/92
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Date: Fri, 8 May 1992 04:47:57 GMT
Forwarded from the Magellan Project
MAGELLAN STATUS REPORT
May 7, 1992
1. Magellan continues to collect radar and gravity data at
Venus under the M2122 command sequence. All systems are
nominal and essentially unchanged since yesterday.
2. The base band phase adjustment at the DSN (Deep Space
Network) High Efficiency (HEF) stations continue to achieve
positive SNR's of 1.5 to 2 db. This brings the high rate
data into the range where usable images can be produced
anytime HEF stations are tracking. Magellan currently has
about 70 to 80 percent tracking coverage with HEF stations.
3. Magellan continues to perform left-look radar mapping
passes from 42 deg. north latitude to 45 deg. south on
seven consecutive orbits, then keeps the high gain antenna
pointed to Earth during the eighth orbit to provide gravity data.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Denial is always the first
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | symptom.
|_____|/ |_|/ |_____|/ |
Article: 954
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space.news
Subject: Magellan Update - 05/08/92
Date: 9 May 92 05:06:42 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from the Magellan Project
MAGELLAN STATUS REPORT
May 8, 1992
1. Magellan continues to orbit Venus under the M2122 command
sequence. The spacecraft is sending science data at 115.2
kbps using the 360 kHz subcarrier, plus the 40 bps X-band
engineering telemetry data.
2. All starcals (star calibrations) since yesterday have been
successful, with only one missed star. The attitude updates
are in the expected range.
3. The temperature of Transmitter B is steady at 52.6 to 53.3 degrees C.
4. Science data communication continues to be satisfactory
over the DSN (Deep Space Network) HEF (High Efficiency) stations,
but marginal during "standard" tracking passes.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Denial is always the first
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | symptom.
|_____|/ |_|/ |_____|/ |
Article: 987
Newsgroups: sci.space.news
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Subject: Magellan Update - 05/11/92
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Date: Tue, 12 May 1992 02:47:30 GMT
Forwarded from the Magellan Project
MAGELLAN STATUS REPORT
May 11, 1992
1. Magellan continues to map Venus under the M2122 command
sequence which started May 1. All systems are nominal and
high rate science data is being successfully received.
2. Twenty of the 22 starcals (star calibrations) performed over
the weekend were fully successful, so the attitude control
remains precise.
3. The base band phase adjustments made at the DSN (Deep Space
Network) stations last week continue to produce a 3 to 4 db
improvement in the signal-to-noise ratio (SNR) of the high
rate data. The SNR at station 65 (Madrid 34 meter antenna)
is presently running +2 to 3 db.
4. Peak temperature of Transmitter B is at 52.6 degrees C on
radar mapping passes and 53.3 degrees on gravity orbits.
This temperature has been stable for about a week and is
expected to remain so until May 22, when the orbit begins
to dip into the shadow of Venus at periapsis.
5. Later today, controllers will uplink the routine weekly
update to the radar control parameters and reset of the
command loss timer.
6. At about midnight (PDT) Thursday, Magellan will start
orbit #4850 which marks the midway point in Cycle 3.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Denial is always the first
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | symptom.
|_____|/ |_|/ |_____|/ |
Article: 989
Newsgroups: sci.space.news
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Subject: Magellan Update - 05/12/92
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Date: Wed, 13 May 1992 02:09:38 GMT
Forwarded from the Magellan Project
MAGELLAN STATUS REPORT
May 12, 1992
1. Magellan continues to map Venus under the M2122 command
sequence which started May 1. All systems remain unchanged
and high rate science data is being successfully received.
2. The star tracker continues to miss a star occasionally,
but even with two partial updates since yesterday the
attitude control remains precise.
3. The DSN (Deep Space Network) stations are still achieving
positive signal-to-noise ratio (SNR) of the high rate data.
The Radar and SAR (Synthetic Aperture Radar) Data Processing
Teams have demonstrated that good images can be produced so
long as the SNR is -.5 db or higher.
4. Peak temperature of Transmitter B is still 52.6 degrees C
on radar mapping passes and 53.3 degrees on gravity
orbits. This temperature has been stable for about a week
and is expected to remain so until May 22, when the orbit
begins to dip into the shadow of Venus at periapsis.
5. Yesterday, controllers uplinked the routine weekly update
to the radar control parameters ("pseudo-tweak") and reset
of the command loss timer.
6. At about midnight (PDT) Thursday, Magellan will start
orbit #4850 which marks the midway point in Cycle 3.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Denial is always the first
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | symptom.
|_____|/ |_|/ |_____|/ |
Article: 1018
Newsgroups: sci.space.news
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Subject: Magellan Update - 05/13/92
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Date: Thu, 14 May 1992 04:43:38 GMT
Forwarded from the Magellan Project
MAGELLAN STATUS REPORT
May 13, 1992
1. Magellan continues to map Venus as it approaches the end
of the M2122 command sequence which started May 1. All
systems remain unchanged and high rate science data is
being successfully received.
2. There has been a flurry of foreground rejects during the
starcals (star calibrations). These are probably due to
protons from increased solar activity. There were five
rejects on orbit #4830 yesterday, and both stars were missed.
However the attitude control remains precise.
3. Yesterday, the spacecraft started a new period of periapsis
earth occultations, when the low part of the orbit passes
behind Venus as viewed from Earth. As of this morning the
time behind Venus is up to five minutes. Since this is
the portion of the orbit for gathering the best gravity
data, we will stop gravity data collection as we start the
next command sequence on Friday.
4. Since April 22nd Magellan has been performing gravity data
collection on every eighth orbit. This involves keeping
the spacecraft pointed to Earth during the periapsis
portion of the orbit to allow for very precise tracking.
5. As of Friday, May 15th, we will have completed 21 gravity
orbits. Gravity data collection will resume at the start
of Cycle 4, 124 days from now. During that cycle
periapsis will be visible for the full 243 days, allowing
gravity data to be collected all the way around Venus.
6. The M2136 command sequence will be uplinked tomorrow and
begin execution on Friday. It will control Magellan for
18 days in a radar mapping only mode. Then we will suspend
radar operations on June 4th as we go into Superior Conjunction.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Denial is always the first
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | symptom.
|_____|/ |_|/ |_____|/ |
|
| 456.486 | Magellan Status, May 19-21 | PRAGMA::GRIFFIN | Dave Griffin | Thu May 21 1992 22:27 | 146 |
| Status report of Magellan for Tuesday, May 19, 1992:
1. Magellan continues to map Venus under the M2136 command
sequence which started May 15. All systems remain
unchanged and high rate science data is being successfully
received.
2. Following the mapping pass on orbit #4881 this morning,
DSS 61 was unable to lock up to either X-band or S-band
signal at the predicted acquisition time of 5:28 AM PDT.
The signal was acquired at 6:12 AM, about 40 minutes late.
3. The playback period which followed appeared normal. The
spacecraft performed its star calibration and returned to
earth point for the second playback period.
4. The problem was traced to equipment failure at DSS 61,
which has requested time to repair the maser,(a microwave
amplifier analogous to a laser, i.e. Microwave
Amplification by Stimulated Emission of Radiation -
MASER).
5. At the start of the next tracking period, DSS-15 had a
problem with their Telemetry Processor Assembly (TPA), but
this was quickly solved and the scheduled tracking array
with DSS-12 was established.
6. Peak temperature of Transmitter B still ranges from 53.3
to 54 degrees C. (This may seem like a strange interval,
but the engineering telemetry reports the temperature in
increments of .7 deg.)
7. The Project Science Group and associated working groups
are meeting this week at JPL.
8. Ray Arvidson, Magellan Radar Investigator, is giving a
Science Briefing on "Venus Surface Processes" tomorrow at
10 AM in von Karman auditorium.
-------------------------------------------------------------------
MGN REPORT 5-20
Magellan Status
Status report of Magellan for Wednesday, May 20, 1992:
1. Magellan continues to map Venus under the M2136 command
sequence which started May 15. All systems remain
unchanged and high rate science data is being successfully
received.
2. Peak temperature of Transmitter B still ranges from 53.3
to 54 degrees C.
3. No spacecraft commanding is planned for today. The
routine update to the radar control parameters (the so-
called "pseudo-tweak") will be uplinked tomorrow.
4. Magellan has now completed 935 orbits in Cycle 3. Usable
radar image data has been received from at least 735
orbits (78.6%), yielding stereo coverage of approximately
20% of the surface of Venus.
5. Ray Arvidson, Magellan Radar Investigator, is giving a
Science Briefing on "Venus Surface Processes" today at 10
AM in von Karman auditorium.
-------------------------------------------------------------------
Magellan Status 5/21/92
PUBLIC INFORMATION OFFICE
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIF. 91109
MAGELLAN STATUS REPORT
May 21, 1992
Magellan continues to map Venus under a command sequence
which started May 15. All systems remain unchanged and high rate
science data are being successfully received. All star
calibrations were successful.
Later today, controllers will uplink a special set of
commands for a three-orbit high resolution altimetry test to be
conducted on Sunday. Commands to return to the left-look mode for
stereo imaging will be approved today and sent to the spacecraft
at the conclusion of the test.
The remaining primary mission objective is the collection
and analysis of high resolution gravity data. The data will
enable scientists to infer the internal structures of Venus which
correlate with the surface features.
Magellan has completed 4,232 mapping orbits of Venus. More
than 97 percent of the surface has been imaged. About 35 percent
of the surface has been imaged in both right and left-look modes
and about 20 percent has been imaged in different, left-look
incidence angles yielding stereo coverage.
_____
MGN REPORT 5/21
Magellan Status
Status report of Magellan for Thursday, May 21, 1992:
1. Magellan continues to map Venus under the M2136 command
sequence. (For those not familiar with the sequence
designations, the M2136 means (M) it is a radar Mapping
sequence. The '2' is the last digit of the year (1992).
This is followed by the day of the year that the sequence
began execution: 136, (May 15).
2. All systems remain unchanged and high rate science data is
being successfully received. All starcals were
successful.
3. Later today the "pseudo-tweak" will be uplinked.
Controllers will also uplink a special set of control
parameters for a 3-orbit High Resolution Altimetry Test to
be performed on Sunday. Commands to return to left-look
(stereo) imaging will be approved today for sending to the
spacecraft at the conclusion of the test.
4. The remaining primary mission objective is the collection
and analysis of high resolution gravity data. This data
will enable scientists to infer the internal structures of
Venus which correlate with the surface features.
5. The proposed plan to aerobrake Magellan into a circular
orbit following Cycle 4 would provide a unique opportunity
to gather high resolution gravity data on a global scale,
as well as improved radar imaging of targetted areas of
scientific interest.
6. Magellan has now completed 4232 mapping orbits of Venus.
Over 97% of the surface has been imaged About 35% of the
surface has been imaged in both right and left-look modes,
and about 20% has been imaged in different, left-look
incidence angles yielding stereo coverage.
|
| 456.487 | Landslides on Venus | CARROL::LEPAGE | Jinky rules!!! | Fri May 29 1992 14:05 | 112 |
| Paula Cleggett-Haleim
NASA Headquarters, Washington, D.C. May 28, 1992
(Phone: 202/453-1547)
Jim Doyle
Jet Propulsion Laboratory, Pasadena, Calif.
(Phone: 818/354-5011)
RELEASE: 92-76
LARGE LANDSLIDES FOUND ON VENUS
Large landslides have been identified on Venus by
Magellan Project scientists at NASA's Jet Propulsion
Laboratory, Pasadena, Calif. They are similar to landslides
that have been known for some time to occur on Earth and
Mars, a project spokesperson said.
Four images, being released today, show evidence of the
landslide process. One image clearly shows rubble beneath a
cliff.
Project Scientist Dr. Steve Saunders said the large
landslides could occur on Venus about as frequently as they
do on Earth, about once a year, but they usually are larger
than terrestrial slides, he said.
Landslides occur on steep slopes that have formed by
faults and on the slopes of volcanoes and generally are
triggered by seismic activity or quakes.
The most dramatic landslides on Venus are seen beneath
the slopes of volcanoes and may have formed much like the
Mount St. Helens eruption in Washington state in 1980,
Saunders said.
"The Mount St. Helens eruption is an example of the
formation of an avalanche caldera where a large portion of
the volcano collapsed and flowed downslope," he said, "but
the avalanche calderas on Venus are much larger."
The larger landslides on Venus spread 18 miles across
the surface. Most Venusian landslides have a rough, hummocky
appearance that is typical of all landslides, he said. They
are made of a jumble of rock fragments of all sizes that
broke up during the violent downhill journey in the few
minutes it takes to form the slides.
Saunders said the size of a landslide depends on the
height of the slope from which it comes and the longest
landslides come from the highest slopes.
The longest known landslides are found on Earth.
Undersea slides reach more than 200 miles in length. Martian
landslides are next in size, with lengths of 60 miles and
more. The largest Venusian landslides extend only about 30
miles.
Since erosion rates on Venus are so low due to the lack
of water on the surface, landslides are an important
mechanism in wearing down mountain regions on Venus. The
rounded hills of the complexly deformed tessera, or tile-
like, terrain on Venus have probably been modified by
numerous landslides, he said.
Magellan has mapped more than 97 percent of the planet,
with about 35 percent of the surface imaged in both right and
left-look modes and about 20 percent imaged in stereo using
different look angles.
JPL manages the Magellan Project for NASA's Office of
Space Science and Applications.
- end -
NOTE TO EDITORS: Magellan images are available to news media
representatives through NASA's Broadcast and Imaging Branch
on 202/453-8375. The photo numbers for images depicting this
landslide activity are: 92-H-364, 92-H-365, 92-H-366 and 92-
H-367.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | The Finagle Factor:
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | Changing the universe to
|_____|/ |_|/ |_____|/ | fit the equation.
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% Subject: Large Landslides Found on Venus
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|
| 456.488 | Magellan Status Reports (5/22/92 - 5/28/92) | PRAGMA::GRIFFIN | Dave Griffin | Mon Jun 01 1992 12:23 | 135 |
|
MAGELLAN STATUS
Status report of Magellan for Friday, May 22, 1992
1. Mapping is continuing at a slightly reduced signal-to-
noise ratio, due to a transmitter temperature decrease of
about 0.7o C. The temperature change was expected as a
result of periapsis occultations which began yesterday.
Occultation duration has reached about 7 minutes per
orbit. Cooling is being experienced in all spacecraft
components.
2. An increase in the on-board radar heater setpoints was
completed this morning to offset the expected cooling
resulting from the occultations. The radar heaters are
being used to warm the adjacent transmitter area to more
precisely control its temperature. Additional warming
will be generated by a solar panel offpoint removal
planned for Tuesday.
3. On-board reception of last night's "pseudo-tweak" required
two attempts. The approaching superior conjunction, when
Venus and Magellan will be behind the sun, is beginning to
interfere with the S-band uplink. One message out of 27
was rejected, so the "pseudo-tweak" was re-sent. The
second attempt was successful.
4. The High-Resolution Altimetry Test is planned to be
performed Sunday. All preparations are on schedule.
5. The quarterly meeting of the PSG concluded Wednesday, May
20. Highlights included presentations on the status of
the Stereo Working Group, results from the recent gravity
experiment over Artemis Chasma, and preliminary results
from the analysis of the radio science experiment
conducted last October.
MGN REPORT 5-26
Magellan Status
Status report of Magellan for Tuesday, May 26, 1992:
1. Magellan continues to map Venus under the M2136 command
sequence which started May 15. All systems are nominal
and high rate science data is being successfully received.
2. All of the starcals performed over the long weekend were
successful, with only one missed star, so the attitude
control remains precise.
3. The 3-orbit High Resolution Altimetry Test was performed
on Sunday. The results will be analyzed after the data
returns to JPL from the DSN stations.
4. The temperature of Transmitter B varies from 53.3 to 54
degrees C. This temperature has been maintained by
changing the radar heater set points such that they remain
on continuously.
5. However, the solar occultations (periods in the shadow of
Venus) are now up to 17 minutes of each orbit and the
temperature of Transmitter B is expected to drop about .7
of a degree during each three days. The effect on
performance will be carefully monitored.
6. We are now about one week from the planned suspension of
radar mapping due to Superior Conjunction. The sun-earth-
Magellan angle is now 5 degrees and will drop below 3
degrees next Tuesday. This is the predicted limit for X-
band communications.
7. During this Superior Conjunction, Venus will actually pass
behind the sun as viewed from Earth. (The November 1991
event saw Venus pass less than 2 degrees from the sun.)
MGN REPORT 5/27
Magellan Status
Status report of Magellan for Wednesday, May 27, 1992:
1. Magellan continues to map Venus under the M2136 command sequence which
started May 15. All systems are nominal and high rate science data is being
successfully received.
2. The temperature of Transmitter B has risen overnight to peak at 56.1
degrees C. The temperature was expected to drop as we entered a season of solar
occultations last Thursday.
3. Spacecraft controllers countered the predicted temperature drop by changing
the radar heater set points and removing the solar panel offpoint, but today
they are discussing a plan to return the solar panels to a 45 degree offpoint
to bring the temperature back down to the preferred range of 52 to 54 degrees.
There is some indication that the temp has leveled off at 55.4 or 56.1 degrees
and may begin to decrease as predicted.
4. The periods in the shadow of Venus are now up to 18 minutes of each orbit.
and the temperature of Transmitter B is expected to drop about .7 degree during
each three days. The effect on performance will be carefully monitored.
5. We are now just 45 orbits from the planned suspension of radar mapping due
to Superior Conjunction. The Sun-Earth-Magellan angle is now 4.8 degrees and
will drop below 3 degrees (the predicted limit for X-band communications)
next Tuesday.
MGN REPORT 5/28
Magellan Status
Status report of Magellan for Thursday, May 28, 1992:
1. Magellan continues to map Venus under the M2136 command
sequence which started May 15. All systems are nominal
and high rate science data is being successfully received.
2. The periods in the shadow of Venus are now up to 18
minutes of each orbit. and the temperature of Transmitter
B has dropped to 53.3 degrees C.
3. We are now just 36 orbits from the planned suspension of
radar mapping due to Superior Conjunction. The Sun-Earth-
Magellan angle is now 4.5 degrees and will drop below 3
degrees (the predicted limit for X-band communica-tions)
next Tuesday.
|
| 456.489 | New MAGELLAN images on CD-ROMs | VERGA::KLAES | All the Universe, or nothing! | Mon Jun 15 1992 15:45 | 119 |
| Article: 44715
Newsgroups: sci.space
From: pgf@space.mit.edu (Peter G. Ford)
Subject: New Magellan Disks Available
Sender: news@athena.mit.edu (News system)
Organization: MIT Center for Space Research
Date: Fri, 5 Jun 1992 18:55:23 GMT
11 new Magellan disks released
------------------------------
NASA's Magellan Project has released a further set of 11 CD-ROMs of
Venus data. Unlike the previous releases of side-looking radar images,
the new disks contain topographic and surface-property data from the
altimetric and radiometric modes of the Magellan instrument. The data
were processed at MIT's Center for Space Research and the disks were
pre-mastered by NASA's Planetary Data System at the Jet Propulsion
Laboratory. They are of two types of disk:
[1] Global Altimetry & Radiometry Data Records (GxDR)
-------------------------------------------------
A single CD-ROM disk labeled USA_NASA_JPL_MG_3001 containing
global images of Venus in four data types:
* Topography (planetary radius) obtained by timing the round-trip
time of altimeter echoes and subtracting the resulting range from
the distance to the Venus center of mass as determined from
Doppler tracking.
* Meter-scale Surface Slope, determined from the time-dispersion
of the altimeter echoes.
* Radar Power Reflection Coefficient, a measure of the surface
composition, obtained from the strength of the altimeter echoes.
* Microwave Emissivity, another measure of the surface composition,
derived from the microwave noise power received from the hot
planetary surface by the Magellan radiometer.
Each data type is represented by four images: a global sinusoidal
projection, an equatorial Mercator projection, and north and south
polar stereographic projections. Each image is in VICAR format and
is divided into 1024x1024 pixel framelets. The pixel size is 5x5
kilometers. The disk contains software for viewing the images from
MS-DOS, Macintosh, and "generic" X11R4.
[2] Altimetry & Radiometry Composite Data Records (ARCDR)
-----------------------------------------------------
10 disks labeled USA_NASA_JPL_MG_2001 through USA_NASA_JPL_MG_2010,
containing all radar-altimeter echoes and radiometer readings from
the first 8 months of mapping, sorted by date and time of measure-
ment. The data fields are a mixture of binary integers and VAX
floating-point numbers. They are NOT images, so you need special
software to access them.
Each disk contains copies of MS-DOS and Macintosh versions of a
program called ARCDRLST that lists the most important fields, along
with C-language source code for ARCDRLST that will compile on many
UNIX and VMS systems. More serious users of ARCDR disks will want
to obtain a copy of the more powerful MGMDQE program which overlays
ARCDR data on other Magellan datasets on Sun SPARC workstations.
Up to date versions of ARCDRLST and MGMDQE are available from an
Internet server at MIT, as described in the next section.
On-Line Access:
--------------
Internet users can examine the GxDR disk, along with several other
Magellan data sets, in the "mgn" directory of the "delcano.mit.edu"
server [18.75.0.80]. If you don't have access to this machine via
"anonymous ftp", a "mail server" is available -- send a message to
"mgn-listserver@space.mit.edu" containing a single line of text:
help
and the server will send you instructions about how to access the
database. Some useful "mgn" sub-directories are:
Bibliography: Information about Venus and Magellan
Bulletins: Magellan news releases
DATA/GxDR: The GxDR CD-ROM (when mounted)
DATA/GIF: Some GxDR images in GIF format
Hyperware: Macintosh documents
bin: Software (ARCDRLST, MGMDQE, etc.)
How to order the CD-ROMs:
------------------------
The CD-ROM disks may be ordered from the National Space Science
Data Center at the Goddard Space Flight Center, as follows:
* via e-mail -- send a mail message to the Coordinated Request and
User Support Office (CRUSO) at:
Internet: request@nssdca.gsfc.nasa.gov
NIS/Decnet: NCF::REQUEST or NSSDCA::REQUEST
* by phone: (301) 286-6695
* by datafax: (301) 286-4952
* by letter (from the USA only):
National Space Science Data Center
CRUSO
Code 933.4
Goddard Space Flight Center
Greenbelt, MD 20771
* by letter (from outside the USA):
World Data Center A for Rockets and Satellites
CRUSO
Code 930.2
Greenbelt, MD 20771
USA
---------------------------------------------------------------------------
Peter G. Ford <pgf@space.mit.edu>
MIT and Magellan Project
|
| 456.490 | Updates - June 9-16 | VERGA::KLAES | All the Universe, or nothing! | Tue Jun 16 1992 22:35 | 276 |
| Article: 1158
Newsgroups: sci.space.news
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Subject: Magellan Update - 06/09/92
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Date: Wed, 10 Jun 1992 02:17:45 GMT
Forwarded from the Magellan Project
MAGELLAN STATUS REPORT
June 9, 1992
1. Magellan has now completed one week of the 23-day Superior
Conjunction period. The spacecraft is operating normally
in a non-mapping mode.
2. The spacecraft remains pointed to Earth, except for star
calibration maneuvers on every fourth orbit. A desaturation
of the momentum wheels is performed on every other orbit.
3. The two starcals yesterday had attitude updates of .023
and .022 degs. The second starcal was partially
successful, with a magnitude reject of one star. That
starcal also set a record for the number of rejects on a
single star scan: 11 foreground filter rejects and 8
background rejects.
4. Transmitter B varies from 52.6 to 54 degress C., with
slightly longer times at the lower temp. The periods in
the shadow of Venus are about 19 minutes of each orbit.
5. Magellan also spends 23 minutes of each orbit in earth
occultation, that is, behind Venus as viewed from Earth.
6. The Sun-Earth-Magellan angle is now 1.27 degrees, so we
are approaching the limits of the uplink X-band communications.
The downlink engineering telemetry remains satisfactory.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Pound for pound,
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | grasshoppers are 3 times as
|_____|/ |_|/ |_____|/ | nutritious as beef.
Article: 1167
Newsgroups: sci.space.news
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Subject: Magellan Update - 06/10/92
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Date: Thu, 11 Jun 1992 04:41:22 GMT
Forwarded from the Magellan Project
MAGELLAN STATUS REPORT
June 10, 1992
1. Magellan is now just 4 days from Superior Conjunction,
when Venus is on the far side of the Sun from Earth. The
spacecraft is operating normally in a non-mapping mode.
Yesterday's starcals were satisfactory.
2. The Sun-Earth-Magellan angle is now less than 1.0 degree.
The downlink engineering telemetry remains satisfactory.
3. The spacecraft remains pointed to Earth, except for star
calibration maneuvers on every fourth orbit. A desaturation
of the momentum wheels is performed on every other orbit.
4. Magellan spends 24 minutes of each orbit in earth
occultation, that is, behind Venus as viewed from
Earth. Transmitter B varies from 52.6 to 54 degress C.,
with slightly longer times at the lower temp. During most
of each earth occultation the spacecraft is also in solar
occultation, that is, in the shadow of Venus.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Pound for pound,
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | grasshoppers are 3 times as
|_____|/ |_|/ |_____|/ | nutritious as beef.
Article: 1190
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space.news
Subject: Magellan Update - 06/11/92
Date: 12 Jun 92 05:18:52 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from the Magellan Project.
MAGELLAN STATUS REPORT
June 11, 1992
1. Magellan is operating normally in a non-mapping mode as it
approaches Superior Conjunction on June 14th. It is
continuously pointed to Earth except for the starcal
(star calibration) maneuver on every fourth orbit. The two
starcals yesterday were successful.
2. The Sun-Earth-Magellan angle is now 0.7 degree. With the
radio signal passing so close to the Sun, it is
increasingly difficult for the DSN (Deep Space Network)
stations to maintain lock on downlink engineering telemetry.
The High Efficiency (HEF) receivers have been able to lock up on
the 40 bps telemetry, with an SNR of 9 to 11 dB, but the
standard stations frequently lose lock. Presently Goldstone
DSS-15 (34 meter antenna) is in lock with an SNR of 8.2 dB.
3. On Saturday, about 20 hours before Superior Conjunction,
Venus will pass behind the disk of the sun. For a period
of several days communication will not be possible.
4. Magellan will continue to operate on its on-board
sequence, and in the event of a spacecraft anomaly, will
switch to on-board fault protection procedures.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Pound for pound,
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | grasshoppers are 3 times as
|_____|/ |_|/ |_____|/ | nutritious as beef.
Article: 1195
Newsgroups: sci.space.news
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Subject: Magellan Update - 06/12/92
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Date: Sat, 13 Jun 1992 04:45:50 GMT
Forwarded from the Magellan Project.
MAGELLAN STATUS REPORT
June 12, 1992
1. Magellan is operating normally in a non-mapping mode as it
approaches Superior Conjunction. It is continuously
pointed to Earth except for the starcal (star calibration)
maneuver on every fourth orbit.
2. Yesterday evening the received signal strength at DSS-45
(Canberra 34 meter antenna) dropped abruptly. It was soon
confirmed that the 360 kHz subcarrier had turned on, indicating
that the spacecraft had experienced another spurious shutoff
(SSO) of the high power amplifier (TWTA). The on-board fault
protection automatically restarts the TWTA and selects the
360 kHz subcarrier.
3. However, we are at a time in the Superior Conjunction
period when we prefer to have the subcarrier off in order
to maximize the 40 bps engineering telemetry. The effect
of turning on the high rate subcarrier was to drop the
telemetry signal "into the mud." Normally the corrective
action would be to uplink express commands to turn the
subcarrier off, but we are below the threshhold for a
reliable command uplink.
4. Controllers decided that the prudent approach would be to
wait until Magellan comes out from behind Venus next Tuesday,
rather than attempting to command the subcarrier off.
5. The Sun-Earth-Magellan angle is now less than 0.4 degrees.
The angle is measured through the centers of the planets,
so we have actually passed the angle at which Magellan is
behind the limb of Venus as viewed from Earth. And,
contrary to what we have stated for the past several
weeks, the smallest angle (i.e. Superior Conjunction)
occurs at 6:00 AM PDT tomorrow, June 13th. At that time
the Sun-Earth-Magellan angle will be 0.1507 deg.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Pound for pound,
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | grasshoppers are 3 times as
|_____|/ |_|/ |_____|/ | nutritious as beef.
Article: 1204
Newsgroups: sci.space.news
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Subject: Magellan Update - 06/15/92
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Date: Tue, 16 Jun 1992 02:06:41 GMT
Forwarded from the Magellan Project
MAGELLAN STATUS REPORT
June 15, 1992
1. Magellan is operating normally in a non-mapping mode as the
mission comes out of its second Superior Conjunction period.
2. Venus passed behind the Sun on Saturday, June 13th, and is
now about .4 deg away from the center point of the Sun.
Since the Sun has a radius of about .25 deg, this places
Venus about .15 deg. from the limb of the solar disk.
3. This geometry means that we have not received any
information about the spacecraft for several days.
Controllers are planning to uplink express commands
tomorrow to turn off the 360 kHz subcarrier. This is
expected to increase the power of the 40 bps X-band
engineering telemetry and allow the Spacecraft Team to
again monitor the health of the spacecraft.
4. The DSN (Deep Space Network) stations are able to detect
Magellan's radio signal, however, confirming that it remains
pointed to Earth (except for the starcal (star calibration)
on every fourth orbit).
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Pound for pound,
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | grasshoppers are 3 times as
|_____|/ |_|/ |_____|/ | nutritious as beef.
Article: 1214
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space.news
Subject: Magellan Update - 06/16/92
Date: 17 Jun 92 03:52:11 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from the Magellan Project
MAGELLAN STATUS REPORT
June 16, 1992
1. Magellan has now completed two weeks of the 23-day
Superior Conjunction period. The spacecraft is apparently
operating normally in a non-mapping mode
2. The spacecraft remains pointed to Earth, except for star
calibration maneuvers on every fourth orbit. A
desaturation of the momentum wheels is performed on every
other orbit.
3. Due to Superior Conjunction we have been unable to obtain
engineering telemetry since Thursday, except for a brief
lockup by one of the 70-m DSN (Deep Space Network) stations
last night.
4. That bit of telemetry indicated that the TWTA (Traveling
Wave Tube Amplifier) may have experienced two spurious shutoffs.
The result would be the same, the TWTA would be restarted and
the 360 kHz subcarrier set to "on." This has the effect of
draining signal strength from the 40 bps engineering telemetry
and dropping it below the lockup threshhold for most DSN stations.
5. Tomorrow morning controllers plan to send commands to
reset the command loss timer to 17 days and to turn off
the 360 kHz subcarrier. The commands will be repeated
five times to increase the probability of being
successfully received by Magellan.
6. Magellan also spends 25 minutes of each orbit in earth
occultation, that is, behind Venus as viewed from Earth.
7. The Sun-Earth-Magellan angle is now back up to 0.76 degrees
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Pound for pound,
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | grasshoppers are 3 times as
|_____|/ |_|/ |_____|/ | nutritious as beef.
|
| 456.491 | Updates - June 17-19 | VERGA::KLAES | All the Universe, or nothing! | Sat Jun 20 1992 19:46 | 188 |
| Article: 1224
Newsgroups: sci.space.news
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Subject: Magellan Update - 06/17/92
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Date: Thu, 18 Jun 1992 04:16:16 GMT
Forwarded from the Magellan Project
MAGELLAN STATUS REPORT
June 17, 1992
1. Magellan is back in communication with the DSN (Deep Space
Network) stations following Superior Conjunctions on Saturday.
Engineering telemetry indicates that all systems are nominal.
2. Early this morning controllers successfully uplinked
commands to reset the command loss timer and to turn off
the 360 kHz subcarrier. This brought the signal to noise
(SNR) of the engineering telemetry back up to 16 db and
enabled the spacecraft engineers to assess the health of
the subsystems.
3. Preliminary indications are that the spacecraft did
experience another TWTA (Traveling Wave Tube Amplifier)
SSO (Spurious Shutoff), in addition to the one last
Thursday which caused the loss of communications. A
readout of the the tape recorded starcal (star calibration)
results will be performed in a few days.
4. The spacecraft remains pointed to Earth, except for star
calibration maneuvers on every fourth orbit. A
desaturation of the momentum wheels is performed on every
other orbit. Transmitter B is stable at 52.6 degrees C.
5. Magellan will resume radar mapping about June 26 when the
X-band communications are expected to be good enough for
high rate science data.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Pound for pound,
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | grasshoppers are 3 times as
|_____|/ |_|/ |_____|/ | nutritious as beef.
Article: 1225
Newsgroups: sci.space.news
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Subject: Magellan Update #2 - 06/17/92
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Date: Thu, 18 Jun 1992 07:32:32 GMT
Forwarded from:
PUBLIC INFORMATION OFFICE
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIF. 91109. TELEPHONE (818) 354-5011
MAGELLAN STATUS REPORT
June 17, 1992
Magellan has resumed communication with the Deep Space Network
stations following a superior conjunction blackout last weekend.
Engineering telemetry indicates that all systems are normal. In
superior conjunction Venus and Earth are on opposite sides of the sun
and communication is interrupted.
Magellan will resume radar mapping on June 26 when the X-band
communications are expected to be good enough for high rate science data.
Early today controllers sent commands to reduce the noise in the
radio carrier signal so engineers could assess the health of the
subsystems. The noise resulted from an apparent spurious shutoff, and
then automatic reactivation, of the transmitter last Thursday.
The spacecraft remains pointed toward Earth, except for star
calibration maneuvers every fourth orbit. A readout of the tape-
recorded star calibration results will be performed in a few days.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Pound for pound,
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | grasshoppers are 3 times as
|_____|/ |_|/ |_____|/ | nutritious as beef.
Article: 1234
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space.news
Subject: Magellan Update - 06/18/92
Date: 19 Jun 92 09:01:10 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from the Magellan Project
MAGELLAN STATUS REPORT
June 18, 1992
1. Magellan is operating normally in a non-mapping mode
following Superior Conjunction on Saturday. Engineering
telemetry indicates that all systems are nominal. Transmitter
B is stable, toggling between 52.6 and 53.3 degrees C.
2. The spacecraft remains pointed to Earth, except for star
calibration maneuvers on every fourth orbit. Of the two
starcals performed since yesterday, one was successful and
the other was partially successful.
3. During the star calibration maneuver, Magellan sweeps its
star scanner across a selected portion of the sky looking
for starlight matching the magnitude of its specified
reference star. It is programmed to reject other glints
of light from dust particles or the effects of energetic
protons from the sun. The light of the reference star
must be detected crossing two slits to be "successful."
4. The detected position of the star is compared to where the
attitude control system expected to find it, and if the
difference is within the innovation bound (normally 0.07
degree), the attitude control data is updated.
5. The process is then repeated with a second reference star
at approximate right angle to the first. If one of these
scans fails to find its reference star, or rejects the
update, the starcal is "partially successful."
6. Magellan will resume radar mapping about June 26 when the
X-band communications are expected to be good enough for
high rate science data.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Pound for pound,
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | grasshoppers are 3 times as
|_____|/ |_|/ |_____|/ | nutritious as beef.
Article: 1240
Newsgroups: sci.space.news
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Subject: Magellan Update - 06/19/92
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Date: Sat, 20 Jun 1992 01:24:17 GMT
Forwarded from the Magellan Project
MAGELLAN STATUS REPORT
June 19, 1992
1. Magellan is operating normally in a non-mapping mode as
the mission approaches the end of its second Superior
Conjunction period. Engineering telemetry indicates that
all systems are nominal. Transmitter B is stable,
toggling between 52.6 and 53.3 degrees C.
2. The spacecraft remains pointed to Earth, except for star
calibration maneuvers on every fourth orbit.
3. Magellan will resume radar mapping about June 26 when the
X-band communications are expected to be good enough for
high rate science data.
4. On Wednesday, Dr. Saunders gave a talk titled "Mysterious
Venus - A Planetary Puzzle" to the Caltech Associates. He
gave illustrated examples of a variety of Venusian
geologic features, while explaining why Venus provides
some profoundly enigmatic views of all the planets. For
example, one river-like channel a mile wide meanders
across the Venusian plains for more than 4000 miles. This
channel is longer than the Nile river, but unlike the
Nile, it was not carved by running water, but by some
unknown liquid. Saunders also talked about large impact
craters, volcanoes, and curious streaks produced by winds
that have scoured the landscape.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Pound for pound,
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | grasshoppers are 3 times as
|_____|/ |_|/ |_____|/ | nutritious as beef.
|
| 456.492 | New images available | PRAGMA::GRIFFIN | Dave Griffin | Tue Jun 23 1992 14:56 | 14 |
| Two new 3D images are available:
MGN_GLOBE_x_3D.GIF - Venus hemisphere (3D perspective)
MGN_LADA_TERRA_x_3D.GIF - Lada Terra region (true 3D -- requires glasses)
Both have .INFO files. The _x_ is 1 or 2 -- different resolutions.
In the archive at pragma::public:[nasa]
I find the GLOBE images to be rather dim. XV can be used to brighten it
up a bit.
- dave
|
| 456.493 | Updates - June 22 to July 9 | VERGA::KLAES | Slaves to the Metal Hordes | Fri Jul 10 1992 16:51 | 747 |
| Article: 1250
Newsgroups: sci.space.news
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Subject: Magellan 3D Images Available
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Date: Mon, 22 Jun 1992 13:53:47 GMT
======================
MAGELLAN 3D IMAGES
June 21, 1992
======================
Four 3D images taken by the Magellan spacecraft of the planet
Venus are now available in GIF and JPEG format. One set of images are
stereo images of the Lada Tera Region on Venus. Red and blue tinted
glasses are needed to properly view these images. The other set of
images are a single frame of the Venus globe taken from a JPL
animation. There are also accompanying captions files which I've
appended to the end of this message. Make sure you are in binary mode
when transferring the image files, and in ASCII mode when transferring
the caption files. The images are available using anonymous ftp at:
ftp: ames.arc.nasa.gov (128.102.18.3)
user: anonymous
cd: pub/SPACE/GIF
files:
3d.gif (steroe image of Lada Tera Region on Venus)
3d_b.gif (Same as 3d.gif but at a different resolution)
3d.txt (Caption file)
globe.gif (Venus globe)
globe1.gif (Same as globe.gif but at a different resolution)
globe.txt (Caption file)
cd: pub/SPACE/JPEG
files:
3d.jpg (steroe image of Lada Tera Region on Venus)
3d_b.jpg (Same as 3d.jpg but at a different resolution)
3d.txt (Caption file)
globe.jpg (Venus globe)
globe1.jpg (Same as globe.jpg but at a different resolution)
globe.txt (Caption file)
---------------------------------------------------------------------------
3D.TXT
PUBLIC INFORMATION OFFICE
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIF. 91109
PHOTO CAPTION MAGELLAN
P-39195
Oct. 29, 1991
This full-resolution mosaic centered at 59.1 degrees south latitude,
86.5 degrees east longitude in the Lada Terra Region on Venus is an
anaglyph, or combined image, consisting of two data sets slightly
displaced from each other and projected in red and blue. This
produces a 3-dimensional or stereo effect when viewed through red and
blue tinted glasses. Magellan "looked" at the surface from different
incidence angles (20 and 14 degrees from a line perpendicular to the
surface) as it passed over the same part of the surface in the first
and second mapping cycles (November 1990 and July 1991, respectively).
The ability to see both the radar image and differences in elevation
together is valuable for geologic interpretation. The image is of an
area approximately 100 kilometers (62 miles) on a side and shows a
deep trough approximately 110 kilometers (68 miles) long, and 8 to 12
kilometers (5 to 7 miles) wide. Analysis of geometric distortions in
the two images shows the trough to be about 800 meters (0.5 mile) deep.
-----------------------------------------------------------------------
GLOBE.TXT
PUBLIC INFORMATION OFFICE
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIF. 91109. TELEPHONE (818) 354-5011
PHOTO CAPTION MAGELLAN
P-39225 MGN 81
Oct. 29, 1991
This global view of the surface of Venus is centered at 180 degrees
east longitude. Magellan synthetic aperture radar mosaics from the
first cycle of Magellan mapping are mapped onto a computer-simulated
globe to create this image. Data gaps are filled with Pioneer-Venus
Orbiter data, or a constant mid-range value. Simulated color is used
to enhance small-scale structure. The simulated hues are based on
color images recorded by the Soviet Venera 13 and 14 spacecraft. The
image was produced by the Solar System Visualization project and the
Magellan Science team at the JPL Multimission Image Processing
Laboratory, and is a single frame from a video released at the October
29, 1991, JPL news conference.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Pound for pound,
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | grasshoppers are 3 times as
|_____|/ |_|/ |_____|/ | nutritious as beef.
Article: 1252
Newsgroups: sci.space.news
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Subject: Magellan Update - 06/22/92
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Date: Tue, 23 Jun 1992 01:33:23 GMT
Forwarded from the Magellan Project
MAGELLAN STATUS REPORT
June 22, 1992
1. Magellan is operating normally in a non-mapping mode as
the mission approaches the end of its second Superior
Conjunction period. Engineering telemetry indicates that
all systems are nominal. Transmitter B is stable,
toggling between 51.9 and 53.3 degrees C.
2. The spacecraft remains pointed to Earth, except for star
calibration maneuvers on every fourth orbit. All star
calibrations were successful over the weekend.
3. Magellan will resume radar mapping on June 26 when the X-
band communications are expected to be good enough for
high rate science data.
4. A special Magellan Project Internal Awards ceremony will
take place on Tuesday, 23 June, 167 Conference Room, 3:00 - 5:00 P.M.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Pound for pound,
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | grasshoppers are 3 times as
|_____|/ |_|/ |_____|/ | nutritious as beef.
Article: 1255
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space.news
Subject: Magellan Update - 06/23/92
Date: 24 Jun 92 05:13:13 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from the Magellan Project
MAGELLAN STATUS REPORT
June 23, 1992
1. Magellan has now completed 21 days of the 23-day Superior
Conjunction period. The spacecraft is operating normally
in a non-mapping mode
2. The spacecraft remains pointed to Earth, except for star
calibration maneuvers on every fourth orbit. A desaturation
of the momentum wheels is performed on every other orbit.
3. Spacecraft controllers will reset the Command Loss Timer
to 96 hours later today.
4. On Thursday, new Kalman gains and a resetting of the Star
Data Invalid counter threshhold will be uplinked in
preparation for the M2178 command sequence to be sent to
Magellan later that day.
5. The M2178 sequence will resume radar mapping, with a
specific target area of Stowe Crater. This is a region
which showed distinct differences between the Cycle 1
left-look images and the Cycle 2 right-look views.
6. To assure coverage of the Stowe Crater area, the radar
mapping passes will be skewed to the south, starting at
2.5 degrees north latitude and extending to 51 degrees south.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Pound for pound,
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | grasshoppers are 3 times as
|_____|/ |_|/ |_____|/ | nutritious as beef.
Article: 1271
Newsgroups: sci.space.news
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Subject: Magellan Update - 06/24/92
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Date: Thu, 25 Jun 1992 03:37:19 GMT
Forwarded from the Magellan Project
MAGELLAN STATUS REPORT
June 24, 1992
1. Magellan has now completed 22 days of the 23-day Superior
Conjunction period. The spacecraft is operating normally
in a non-mapping mode
2. The spacecraft remains pointed to Earth, except for star
calibration maneuvers on every fourth orbit. A
desaturation of the momentum wheels is performed on every
other orbit.
3. This morning spacecraft controllers are resetting the
Command Loss Timer to 96 hours. Tomorrow, new Kalman
gains and a resetting of the Star Data Invalid counter
threshhold will be uplinked in preparation for the M2178
command sequence to be sent to Magellan later that day.
4. The M2178 sequence will resume radar mapping, with a
specific target area of Stowe Crater. This is a region
which showed distinct differences between the Cycle 1
left-look images and the Cycle 2 right-look views.
5. To assure coverage of the Stowe Crater area, the radar
mapping passes will be skewed to the south, starting at
2.5 degrees north latitude and extending to 51 degrees south.
6. When Magellan resumes radar mapping on Friday a few
minutes before 2 PM PDT, it will be ending the longest
non-mapping period since it arrived at Venus in 1990. For
23 days and 180 orbits, the spacecraft "stood down" while
Venus passed on the far side of the sun.
7. The stereo imaging of the planet is then scheduled to
continue for 147 days, through the first six weeks of Cycle 4.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Pound for pound,
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | grasshoppers are 3 times as
|_____|/ |_|/ |_____|/ | nutritious as beef.
Article: 1274
Newsgroups: sci.space.news
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Subject: Macintosh Images
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Date: Thu, 25 Jun 1992 12:19:46 GMT
=============================
MACINTOSH IMAGES
June 24, 1992
=============================
Two images are now available that can be displayed on the older
black-and-white Machintoshes. One image is of the "new" NASA logo, and the
other image is the Venus globe put together from the data from the Magellan
spacecraft. If the images are placed in the System folder of the computer and
named "StartupScreen", the images will automatically be displayed when the
computer is turned on. The images have been dithered to replace the grey
values with varying densities of black and white and are stored in the
MacBinary format. The images can be retrieved from the Ames site using
anonymous ftp.
ftp: ames.arc.nasa.gov (128.102.18.3)
user: anonymous
cd: pub/SPACE/MAGELLAN
files: nasalogo.mac (MacBinary format)
venus.mac (MacBinary format)
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Pound for pound,
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | grasshoppers are 3 times as
|_____|/ |_|/ |_____|/ | nutritious as beef.
Article: 1276
Newsgroups: sci.space.news
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Subject: Magellan Update #2 - 06/24/92
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Date: Thu, 25 Jun 1992 23:49:21 GMT
Forwarded from:
PUBLIC INFORMATION OFFICE
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIF. 91109. TELEPHONE (818) 354-5011
MAGELLAN STATUS REPORT
June 24, 1992
Magellan is operating normally in a non-mapping mode.
Tomorrow marks the end of the 23-day superior conjunction period,
when Earth and Venus are on opposite sides of the sun.
The spacecraft remains pointed toward Earth except for star
calibration maneuvers on every fourth orbit. A new command
sequence is to be uplinked to the spacecraft tomorrow to resume
mapping Friday with a specific target area of Stowe Crater. That
is a region which showed distinct differences between the left-
look images in cycle one and the right-look images in cycle two.
To assure coverage of the crater area the radar mapping
passes will be skewed to the south so mapping will start at 2.5
degrees north latitude and extend to 51 degrees south latitude.
Stereo imaging of Venus will continue for 147 days, through
the first six weeks of cycle 4. When Magellan resumes mapping it
will end the longest non-mapping period since it arrived at Venus
in 1990; for 23 days and 180 orbits, the spacecraft waited while
Venus passed on the far side of the sun.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Pound for pound,
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | grasshoppers are 3 times as
|_____|/ |_|/ |_____|/ | nutritious as beef.
Article: 1304
Newsgroups: sci.space.news
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Subject: Magellan Update - 06/26/92
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Date: Sat, 27 Jun 1992 06:07:35 GMT
Forwarded from the Magellan Project
MAGELLAN STATUS REPORT
June 26, 1992
1. Magellan will end its 23-day "vacation" from radar mapping
at 2:42 PM PDT today.
2. The M2178 command sequence is successfully on-board and
the spacecraft has been configured to resume mapping.
Magellan will return to performing a starcal (star
calibration) on every orbit and a desaturation of the
momentum wheels on every other orbit.
3. Mapping will begin just east of Atla Region at the eastern
end of Aphrodite Terra and will extend from 2.5 degrees
north latitude to 51 degrees south.. This includes the
area of Stowe Crater which showed distinct differences
between the Cycle 1 left-look images and the Cycle 2
right-look views.
4. All spacecraft systems are performing nominally. The
temperature of Transmitter B continues to cycle between
52.6 and 54 deg. C.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Pound for pound,
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | grasshoppers are 3 times as
|_____|/ |_|/ |_____|/ | nutritious as beef.
Article: 1323
Newsgroups: sci.space.news
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Subject: Magellan Update - 06/29/92
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Date: Tue, 30 Jun 1992 01:41:55 GMT
Forwarded from the Magellan Project
MAGELLAN STATUS REPORT
June 29, 1992
1. Magellan has resumed radar mapping of Venus and is
operating normally The spacecraft began mapping again
with orbit #5164 on Friday afternoon and has completed 20
orbits since then.
2. In the mapping mode, Magellan performs a starcal (star
calibration) on every orbit. Since Friday afternoon there
have been about ten partially successful starcals, but the
pointing accuracy remains precise.
3. The DSN (Deep Space Network) stations are successfully locking
up to the 115 kbps science data, with signal-to-noise ratios
as high as +2 dB. However, the earthquakes on Sunday disrupted
operations at Goldstone and we're not expecting to receive
X-band data there today.
4. There are preliminary indications that we received good
data for the orbits which re-image the area of Stowe
Crater. This is a region which showed distinct
differences between the Cycle 1 left-look images and the
Cycle 2 right-look views.
5. Transmitter B is varying between 54.7 and 55.4 degress C.
6. The present radar mapping passes start at 2.5 degrees north
latitude and extend to 51 degrees south latitude in the region
souteast of Atla Regio.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Pound for pound,
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | grasshoppers are 3 times as
|_____|/ |_|/ |_____|/ | nutritious as beef.
Article: 1340
Newsgroups: sci.space.news
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Subject: Magellan Update - 06/30/92
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Date: Wed, 1 Jul 1992 02:37:34 GMT
Forwarded from the Magellan Project
MAGELLAN STATUS REPORT
June 30, 1992
1. Magellan has resumed radar mapping of Venus and is
operating normally. The spacecraft began mapping again
with orbit #5164 on Friday afternoon and has completed 28
orbits since then.
2. All starcals (star calibrations) yesterday were successful.
Transmitter B is varying between 54.7 and 55.4 degress C and
peaks briefly to 56.1 before each mapping pass.
3. The DSN (Deep Space Network) stations are successfully locking
up to the 115 kbps science data, with signal-to-noise ratios
as high as +5 dB.
4. This morning the Radar System Engineering Team reported
that the EDR's (Experiment Data Record) of the orbits covering
the area of Stowe Crater look good. Processing of these records
into images is being expedited and the results are expected by
early afternoon.
5. This is a region which showed distinct differences between
the Cycle 1 left-look images and the Cycle 2 right-look
views. The orbits at the start of this sequence were
designed to duplicate the look angles of Cycle 1 in order
to compare the area's appearance now versus 16 months ago.
6. Spacecraft controller are planning to return to the stereo
look angles on Thursday.
7. The present radar mapping passes start at 2.5 degrees
north latitude and extend to 51 degrees south latitude in
the region southeast of Atla Regio.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Pound for pound,
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | grasshoppers are 3 times as
|_____|/ |_|/ |_____|/ | nutritious as beef.
Article: 1346
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space.news
Subject: Magellan Update - 07/01/92
Date: 2 Jul 92 01:08:59 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from the Magellan Project
MAGELLAN STATUS REPORT
July 1, 1992
1. Magellan continues to map Venus and is operating normally.
The spacecraft began mapping following its second Superior
Conjunction with orbit #5164 on Friday afternoon and has
completed 36 orbits since then.
2. All starcals (star calibrations) yesterday were successful
except for one missed star. Transmitter B is varying between
54.7 and 55.4 degress C. The peaks to 56.1 reported yesterday
were seen in the delayed engineering data (DED) relayed to
earth. No memory readouts of DED were obtained yesterday.
3. Later today spacecraft controllers will uplink the radar
mapping parameters to return to the stereo look angles.
The orbits at the start of this sequence were designed to
duplicate the look angles of Cycle 1 in order to compare
the Stowe Crater area's appearance now versus 16 months ago.
4. Yesterday a significant number of Magellan Project
personnel, past and present, were honored with individual
and group awards during the annual NASA Honor Awards
ceremony at JPL.
5. MIT has completed the processing of Cycle 2 altimetry and
radiometry data, which will be published as a set of six
CD-ROMs to complement the eleven previous altimetry/radiometry
CDs released to the science community in June.
6. The Cycle 2 data fills gaps in the southern hemisphere.
In addition, due to the orbit trim maneuver at the end of
Cycle 1 which interleaved the ground track with the
earlier tracks, the new altimetry measurements improve the
resolution of the topographic and surface data sets for
more than 50% of the Venus surface.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | In 1991 there were 16 names
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | listed on the FBI's ten
|_____|/ |_|/ |_____|/ | most wanted list.
Article: 1363
Newsgroups: sci.space.news
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Subject: Magellan Update - 07/02/92
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Date: Fri, 3 Jul 1992 05:44:30 GMT
Forwarded from the Magellan Project
MAGELLAN STATUS REPORT
July 2, 1992
1. Magellan has resumed radar mapping of Venus and is
operating normally. The spacecraft began mapping again
with orbit #5164 on Friday afternoon and has completed 43
orbits since then.
2. All starcals (star calibration) yesterday were successful,
with the exception of one partial starcal.
3. With the successful completion of the Stowe Crater area,
commands were uplinked to the spacecraft to return to the
Cycle 3 stereo look angle.
4. Transmitter B temperatures continue to vary between 54.7
to 56.1 degrees C. Because the temperatures are slightly
higher than pre-Superior Conjunction and because the 115
kbps SNR's haven't been as high as expected, commands are
being uplinked to the spacecraft to lower the Radar Heater
Set points. This should result in a lowering of
Transmitter B's temperature by 1-1.5 degrees C.
5. The present radar mapping passes start at 2.5 degrees
north latitude and extend to 51 degrees south latitude in
the region southeast of Atla Regio.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | In 1991 there were 16 names
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | listed on the FBI's ten
|_____|/ |_|/ |_____|/ | most wanted list.
Article: 1375
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space.news
Subject: Magellan Update - 07/06/92
Date: 7 Jul 92 04:38:01 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from the Magellan Project
MAGELLAN STATUS REPORT
July 6, 1992
1. Magellan continues to perform mapping operations but high
rate data recovery over the weekend was marginal except
one 70 meter and one 34 meter array pass. Most starcals
(star calibrations) were successful and the spacecraft
continues in good engineering condition.
2. Because transmitter B temperatures were running somewhat
high last week, 54 to 55 degrees C, commands were uplinked
to reduce the temperatures. Over the weekend temperatures
dropped to a 52 to 53 degree C range. This seems to have
had an adverse effect on the high rate 115 kbps data
recovery except for a few passes. Previously this lower
temperature range yielded good data most of the time.
3. As Magellan continues to return from the recent superior
conjunction, signal levels will improve. Other steps on
temperature control are also being considered at this time.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | In 1991 there were 16 names
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | listed on the FBI's ten
|_____|/ |_|/ |_____|/ | most wanted list.
Article: 1393
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space.news
Subject: Magellan Update - 07/07/92
Date: 8 Jul 92 03:03:18 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from the Magellan Project
MAGELLAN STATUS REPORT
July 7, 1992
1. Magellan continues to operate normally, performing stereo
mapping of Venus, but the radio signal remains marginal to
poor at the DSN (Deep Space Network) stations.
2. Since last Thursday, when commands were sent to change the
radar heater set points, Transmitter B is varying between
52.6 and 53.3 degrees C. Prior to Superior Conjunction
this was a satisfactory temperature range for obtaining
high rate science data, but the present signal-to-noise
ratio is from -1 to 0 dB.
3. An engineering review meeting this morning discussed
options for improving the telecommunications, including
raising the transmitter temperature into the high 50's. A
primary goal is to restore radar data reception in time to
fill the coverage gap which remains at the end of the cycle,
while preserving capabilities for gravity data collection.
4. The third quarterly release of photo products for the year
occurred on July 1. The list included 144 products and
will be distributed by DMAT (Data Management and Archive
Team) during July and August.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | In 1991 there were 16 names
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | listed on the FBI's ten
|_____|/ |_|/ |_____|/ | most wanted list.
Article: 1405
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space.news
Subject: Magellan Update - 07/08/92
Date: 9 Jul 92 01:55:34 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from the Magellan Project
MAGELLAN STATUS REPORT
July 8, 1992
1. Magellan continues to operate normally, performing stereo
mapping of Venus, but the radio signal remains marginal to
poor at the DSN (Deep Space Network) stations.
2. Since yesterday the Star Data Invalid counter incremented
by two, indicating two missed stars. Transmitter B is
peaking at 54.7 degrees C. Prior to Superior Conjunction
this was a satisfactory temperature range for obtaining
high rate science data, but the present signal-to-noise
ratio is from -2 to 0 dB.
3. Today spacecraft controllers plan to uplink a software
"patch" to make it easier to reset the radar system
heaters. This will consist of nine non-standard commands.
The actual implementation of the software patch is planned
for next Monday.
4. The Spacecraft Team is looking for a way to maintain
closer control of spacecraft temperatures, especially
Transmitter B, the the hope of finding an operating range
which will restore radar data reception in time to fill
the coverage gap which remains at the end of the cycle.
5. Tomorrow the M2192 command sequence will be uplinked, to
take effect on Friday at 11:16 AM PDT. This sequence
would shift the radar mapping swaths to cover the area
from 28 north latitude to 31 south, sweeping across Hecate
and Parga chasms, but no science data is expected until
the telecommunications are improved.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | In 1991 there were 16 names
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | listed on the FBI's ten
|_____|/ |_|/ |_____|/ | most wanted list.
Article: 1415
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space.news
Subject: Magellan Update - 07/09/92
Date: 10 Jul 92 01:49:11 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from the Magellan Project
MAGELLAN STATUS REPORT
July 9, 1992
1. Magellan continues to operate normally, performing stereo
mapping of Venus, but the signal-to-noise ratio at the DSN
(Deep Space Network) stations remains below 0 dB.
2. Yesterday controllers sent twelve non-standard commands,
most related to the software patch to facilitate control
of the radar heater setpoints. In the process, they
turned off the 360 kHz subcarrier and turned on 1200 bps
engineering telemetry to provide more visibility to the
spacecraft systems.
3. At this stage they discovered that the attitude control
system had accepted a bad update of .14 degree, so they
suspended the process of putting the software patch
onboard while they corrected the attitude. This required
disabling the gyro bias temporarily until the spacecraft
completed two successful starcals (star calibrations) on
the subsequent orbits.
4. The uplink of the software patch was completed and memory
readouts performed to verify that it was correctly loaded
into the onboard computer. One portion of the readout was
suspect, so the MRO will be repeated late today. The
software patch is to be enabled on Monday.
5. The 360 kHz subcarrier and 40 bps engineering telemetry
were turned on.
6. Today the M2192 command sequence will be uplinked, to take
effect tomorrow at 11:16 AM PDT. This sequence will shift
the radar mapping swaths to cover the area from 28 north
latitude to 31 south, but no science data is expected
until the telecommunications are improved.
7. At 4:30 PM PDT today there will be a retirement party for
Jim Scott, Magellan Project Manager. Jim has been at JPL
for over 35 years and we wish him a glorious retirement!
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | In 1991 there were 16 names
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | listed on the FBI's ten
|_____|/ |_|/ |_____|/ | most wanted list.
|
| 456.494 | Updates - July 10-16 | VERGA::KLAES | Slaves to the Metal Hordes | Fri Jul 17 1992 18:31 | 269 |
| Article: 1426
Newsgroups: sci.space.news
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Subject: Magellan Update - 07/10/92
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Date: Sat, 11 Jul 1992 04:14:47 GMT
Forwarded from the Magellan Project
MAGELLAN STATUS REPORT
July 10, 1992
1. At Jim Scott's retirement party yesterday, Dr. Ed Stone
announced that Magellan had been named the recipient of
the Smithsonian's 1992 Air & Space Award.
2. Magellan continues to operate normally, performing stereo
mapping of Venus, but the signal-to-noise ratio at the DSN
(Deep Space Network) stations remains below 0 dB. Magellan
has completed 4890 orbits since it began mapping on
September 15, 1990.
3. Yesterday controllers uplinked the M2192 command sequence
which will take effect 11:16 AM PDT. This sequence will
shift the radar mapping swaths to cover the area from 28
north latitude to 31 south, but no science data is
expected until the telecommunications are improved.
4. The memory readout (MRO) of the software patch uplinked
Wednesday was completed and is being analyzed. Another
software patch related to the Star Data Invalid Counter
was uplinked, but its MRO indicates some bit errors so the
patch will be uplinked again.
5. The final announcement of the International Colloquium on
Venus was released June 25th. The 3-day event will be
held at Caltech from August 10 through 12, 1992. Many
papers based on analysis of Magellan data will be presented.
6. A public lecture by Dr. A. T. "Sasha" Basilevsky, from the
Vernadsky Institute, Russian Academy of Sciences, on "View
of Venus: An Historical Perspective" will be hosted by the
Planetary Society on August 10 in association with the Colloquium.
7. Magellan's data management and archive team (DMAT)
announced on July 3 that the total number of distributed
products to the public and science community is 128,844.
This includes 86,566 photoproducts, 28,161 CDs, and 12,186
digital tapes.
8. Dr. Jeffrey Plaut of the Magellan Science Team gave a tour
through the Magellan science area to DSN managers and trainees.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | In 1991 there were 16 names
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | listed on the FBI's ten
|_____|/ |_|/ |_____|/ | most wanted list.
Article: 1438
Newsgroups: sci.space.news
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Subject: Magellan Update - 07/13/92
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Date: Tue, 14 Jul 1992 02:38:56 GMT
Forwarded from the Magellan Project
MAGELLAN STATUS REPORT
July 13, 1992
1. Magellan continues to operate normally under the M2192
command sequence, performing stereo mapping of Venus, but
the signal-to-noise ratio at the DSN (Deep Space Network)
stations remains below 0 dB.
2. The Star Data Invalid Counter incremented by nine over the
weekend, indicating that number of missed stars during
routine star calibration maneuvers. The Spacecraft Team
is studying when the misses occured and what effect they
had on the attitude control.
3. Today controllers are planning to implement the software
patch to control the radar heater setpoints. It has been
decided that the heaters will be turned off to bring the
spacecraft temperatures back down. Transmitter B is now
at 53.3 deg. C.
4. In order to save transmitter lifetime for high priority
radar mapping in early September, a plan has been set up
to swap from Transmitter B to Transmitter A. The swap is
expected to be completed by Wednesday, July 15.
5. This will cause a temporary interuption in SAR (Synthetic
Aperture Radar) data acquisition while the Project formulates
the best Transmitter B operational mode for filling the one
remaining gap in surface image coverage.
6. Gravity data acquisition during Cycle 4 is unaffected by
selection of either transmitter since only the carrier
signal is required.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | In 1991 there were 16 names
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | listed on the FBI's ten
|_____|/ |_|/ |_____|/ | most wanted list.
Article: 1460
Newsgroups: sci.space.news
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Subject: Magellan Update - 07/14/92
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Date: Wed, 15 Jul 1992 04:50:44 GMT
Forwarded from the Magellan Project
MAGELLAN STATUS REPORT
July 14, 1992
1. Magellan continues to operate under the M2192 command
sequence, but due to degradation of high rate
telecommunications the 360 kHz subcarrier has been turned off.
2. Both stars were missed on orbit #5288 yesterday and one
was missed on orbit #5292 last night, but the attitude
control remains precise.
3. Yesterday controllers implemented the software patch to
control the radar heater setpoints. Transmitter B is now
at 49.8 deg. C.
4. Later today they expect to swap the High Gain Antenna to
S-band and swap from Receiver B to Receiver A. Early tomorrow,
a swap from Transmitter B to Transmitter A is planned.
5. All of these spacecraft reconfigurations are designed to
preserve Transmitter B performance for high priority radar
mapping in early September.
6. This has required a temporary interuption in SAR (Synthetic
Aperture Radar) data acquisition while the Project formulates
the best Transmitter B operational mode for filling the one
remaining gap and for later mapping operations.
7. Recovery of this so-called "Thermal/Transmitter Gap" would
add about 1.5% to the Venus surface coverage of the
Magellan mission, bringing the total to about 99%. The
primary mission objective was to achieve at least 70%.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | In 1991 there were 16 names
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | listed on the FBI's ten
|_____|/ |_|/ |_____|/ | most wanted list.
Article: 1465
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space.news
Subject: Magellan Update - 07/15/92
Date: 16 Jul 92 02:49:15 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from the Magellan Project
MAGELLAN STATUS REPORT
July 15, 1992
1. Magellan continues to operate under the M2192 command
sequence, but due to degradation of high rate
telecommunications the 360 kHz subcarrier has been turned off.
2. Yesterday controllers continued the process of
reconfiguring the spacecraft by swapping the High Gain
Antenna to S-band and swapping from Receiver B to Receiver A.
3. The swap from Transmitter B to Transmitter A was completed
early today. Transmitter B continues to cool and is now
down to 28.2 deg. C.
4. All of these spacecraft reconfigurations are designed to
preserve Transmitter B performance for high priority radar
mapping in early September and for later mapping operations.
5. Recovery of this so-called "Thermal/Transmitter Gap" would
add about 1.5% to the Venus surface coverage of the
Magellan mission, bringing the total to about 99%. The
primary mission objective was to achieve at least 70%.
6. Magellan's objective of obtaining a full cycle of gravity
data during Cycle 4 is unaffected by the transmitter
concerns because only the carrier signal is required.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | In 1991 there were 16 names
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | listed on the FBI's ten
|_____|/ |_|/ |_____|/ | most wanted list.
Article: 1475
Newsgroups: sci.space.news
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Subject: Magellan Update - 07/16/92
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Date: Fri, 17 Jul 1992 02:02:20 GMT
Forwarded from the Magellan Project
MAGELLAN STATUS REPORT
July 16, 1992
1. Magellan continues to operate under the M2192 command
sequence, but due to degradation of high rate
telecommunications we are not presently receiving radar
image data at the DSN (Deep Space Network) stations.
2. This means that the spacecraft is performing its normal
radar mapping maneuvers, collecting the echoes from the
surface of Venus, and recording the data on the spacecraft
tape recorder. The spacecraft maneuvers to playback
attitude and plays the data from the tape recorder. But
at that point the process stops because the transmitter in
use cannot put the data onto the carrier signal for
sending to Earth.
3. Yesterday controllers continued the process of
reconfiguring the spacecraft by swapping from Transmitter
B to Transmitter A and adjusting the on-board fault
protection routines. The Transmitter B temperature has
settled between 29.7 and 30.4 deg. C.
4. This status of the mission is expected to continue until
about August 21 when controllers will again attempt to use
Transmitter B. Either they will design the mapping
sequence to keep the transmitter temperature low by power
cycling, or allow the temperature to stabilize in the high
50's as it was during mapping operations after Superior
Conjunction in June.
5. Both of these approaches have demonstrated satisfactory
performance at some time since we switched to Transmitter
B in January, but the mechanism causing the noise spur is
still being studied and what works one week may not work
the next.
6. All of these spacecraft reconfigurations are designed to
preserve Transmitter B performance for high priority radar
mapping in early September and for later mapping operations.
7. Magellan's objective of obtaining a full cycle of gravity
data during Cycle 4 is unaffected by the transmitter
concerns because only the carrier signal is required.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Most of the things you
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | worry about will never
|_____|/ |_|/ |_____|/ | happen.
|
| 456.495 | Updates - July 17-24 | VERGA::KLAES | Slaves to the Metal Hordes | Fri Jul 24 1992 22:04 | 235 |
| Article: 1483
Newsgroups: sci.space.news
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Subject: Magellan Update - 07/17/92
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Date: Sat, 18 Jul 1992 06:02:00 GMT
Forwarded from the Magellan Project
MAGELLAN STATUS REPORT
July 17, 1992
1. Magellan continues to operate under the M2192 command
sequence, but due to degradation of high rate
telecommunications we are not presently receiving radar
image data at the DSN (Deep Space Network) stations. The
Transmitter B temperature continues at about 30 degrees C.
There were two partially successful starcals (star
calibrations) yesterday. No commanding of the spacecraft
is planned between now and Monday.
2. The present status of the mission is expected to continue
until about August 21 when controllers will again attempt
to use Transmitter B for radar mapping. One of the
options is to design the mapping sequence to keep the
transmitter temperature low by power cycling. This means
the transmitter would be turned on to send radar data to
Earth and turned off while data is being collected.
Another option would be to allow the temperature of
Transmitter B to stabilize in the high 50's. (The
qualification temperature of the transmitter is 65 degrees C.)
3. Both of these approaches have demonstrated satisfactory
performance at some time since we switched to Transmitter
B in January. JPL telecommunications engineers are
working hard to model the mechanism causing the noise spur
so that the most effective option can be chosen.
4. On Tuesday, Jeff Miller presented a talk titled "Managing
the Magellan Data Firehose" in the continuing SSORCE
series of Lessons Learned seminars. He spoke about the
Data Management and Archive Team, the centralized approach
to data management unique to Magellan, and the lessons
learned during development and operations.
5. This week project scientist, Dr. Stephen Saunders, and
investigators, Dr. Jim Head, and Dr. Gordon Petengill
attended the Vernadsky-Brown Microsymposium in Moscow.
6. On July 14 deputy project scientist, Dr. Ellen Stofan
inverviewed with Dr. Jeff Kirsch of the Reuben Fleet Space
Theater and Science Center in San Diego. On July 15 Dr.
Stofan gave a tour of the Magellan science area to Rene
Pellat, Advisor to the Director General of CNES for
Science and Technology. She gave a briefing on Magellan
to the Young Presidents group on Friday July 17.
7. On Thursday, July 16 Tommy Thompson, Science and Mission
Planning Office Manager gave a talk in San Jose to Cosmo
Com, a group of amatuer astronomers.
8. Two intern students, Victoria Hamilton of Occidental and
Kristin Cotugno of Univ. of Massachussets in Amherst, are
spending the summer analyzing certain regions of the
surface by creating geologic maps and studying specific
aspects of Venusian geology such as the nature of corona chains.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Most of the things you
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | worry about will never
|_____|/ |_|/ |_____|/ | happen.
Article: 1497
Newsgroups: sci.space.news
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Subject: Magellan Update - 07/20/92
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Date: Tue, 21 Jul 1992 02:48:36 GMT
Forwarded from the Magellan Project
MAGELLAN STATUS REPORT
July 20, 1992
1. Magellan continues to operate under the M2192 command
sequence, but due to degradation of high rate
telecommunications we are not presently receiving radar
image data at the DSN (Deep Space Network) stations.
All starcals (star calibrations) over the weekend were
successful.
2. The Transmitter B temperature continues at about 30 degrees C.
Spacecraft controllers are planning to lower the radar
heater set points to effectively turn off the heaters, and
to offpoint the solar panels to minimize the excess
electrical power which must be radiated to space as heat.
The effect of these changes will be to further drop the
Transmitter B temperature.
3. The present status of the mission is expected to continue
until about August 21 when controllers will again attempt
to use Transmitter B for radar mapping. One of the
options is to design the mapping sequence to keep the
transmitter temperature low by power cycling. This means
the transmitter would be turned on to send radar data to
Earth and turned off while data is being collected.
Another option would be to allow the temperature of
Transmitter B to stabilize in the high 50's. (The
qualification temperature of the transmitter is 65 deg.
C.) Both of these approaches have demonstrated
satisfactory performance at some time since we switched to
Transmitter B in January.
4. The objective is to obtain radar images of the only
significant gap in Magellan's global coverage of Venus, a
10-day mapping segment at the end of the cycle.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Most of the things you
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | worry about will never
|_____|/ |_|/ |_____|/ | happen.
Article: 1510
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space.news
Subject: Magellan Caption Files
Date: 22 Jul 92 06:02:52 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
==========================
MAGELLAN CAPTION FILES
July 21, 1992
==========================
An updated version of the caption files for the Magellan images is now
available. These caption files contain detailed descriptive text of the public
released Venus images taken by the Magellan spacecraft. The caption files are
provided in four formats: ASCII format, IBM Wordperfect 5.1 format, IBM Word
format, and a Macintosh Word format compressed with the Stuffit program
(MacBinary format). The files are available using anonymous ftp at:
ftp: ames.arc.nasa.gov (128.102.18.3)
user: anonymous
cd: pub/SPACE/MAGELLAN
files: captions.txt (ASCII)
capstxt.zip (ASCII -> PKZIP)
capswp5.zip (IBM PC Wordperfect 5.1 -> PKZIP)
capswrd.zip (IBM PC Word -> PKZIP)
captions.sit (Macintosh Word -> Stuffit)
Each caption is identified by a P number. With this P number you can
obtain the corresponding photograph from one of the following places:
Newell Color Lab
221 N. Westmoreland Avenue
Los Angeles CA 90064
Telephone: (213) 380-2980
Fax: (213) 739-6984
OR
National Space Science Data Center
Goddard Space Flight Center
Greenbelt, Maryland 20771
Telephone: (301) 286-6695
Email address: request@nssdca.gsfc.nasa.gov
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Most of the things you
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | worry about will never
|_____|/ |_|/ |_____|/ | happen.
Article: 1540
Newsgroups: sci.space.news
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Subject: Magellan Update - 07/24/92
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Date: Sat, 25 Jul 1992 02:47:54 GMT
Forwarded from the Magellan Project
MAGELLAN STATUS REPORT
July 24, 1992
1. Since Monday, July 20, Magellan has continued to perform
a normal mapping command sequence, but with transmission
of radar data back to earth suspended. Today a new
sequence, M2206, will be started which will keep the High
Gain Antenna pointed toward Earth to support maximum
gravity measurements using Transponder A.
2. Since turn off, Transponder B has cooled to about 24 C
with the temperature reductions obtained this week by
completion of radar heater turn off and offpointing the
solar panels to eliminate excess electrical power. These
actions have prepared Magellan for a Transponder B test
next week (July 28) when the transmitter will be turned
on to observe the behavior of its x-band signal as the
transmitter warms up. Information on cold mode and warm
mode of operations will be tested. This test will be
stopped after two days and transponder B will be turned off.
3. After the transponder B test, normal gravity tracking
operations will resume with transponder A while
transponder B test results are analyzed in preparation
for future radar mapping operations in early September.
4. Plans for the gravity Orbit Trim Maneuver on September
14, 1992 continue on schedule to begin Cycle-4 operations
from a lower orbital periapsis to enhance gravity data collection.
5. The Data Management and Archive Team has completed the
second delivery of Magellan data product catalog
information to the Planetary Data System for their use in
cataloging Magellan data products. This delivery
represents Magellan data collected from 15 September 1990
through 17 May 1991, which includes 6,513 data products.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Most of the things you
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | worry about will never
|_____|/ |_|/ |_____|/ | happen.
|
| 456.496 | International Venus Colloquium, August 10-12 | VERGA::KLAES | Slaves to the Metal Hordes | Fri Jul 31 1992 14:40 | 55 |
| Article: 25140
Newsgroups: sci.space,sci.astro
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Subject: International Venus Colloquium
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Date: Fri, 31 Jul 1992 06:09:54 GMT
This is being forwarded from a Magellan team member.
*****************************************************
From August 10-12, 1992, an "International Venus Colloquium" will
be help at the California Institute of Technology's Ramo Auditorium in
Pasadena. More than 100 scientific researchers from around the world
will present their results based on data from NASA's Magellan and
Pioneer Venus missions and on earlier Soviet missions to Venus. The
colloquium will be particularly timely, as Magellan has almost
completed its third radar mapping cycle around Venus, while Pioneer
Venus is nearing its final entry into the planet's atmosphere.
The Lunar and Planetary Institute is providing organization for
the colloquium. Pam Jones (telephone 713-486-2150, facsimile
713-486-2160) is the point of contact for registration or logistics
questions.
The conveners of the scientific program are Dr. R. Stephen
Saunders at JPL (telephone 818-393-0877, facsimile 818-393-0530) and
Dr. Sean C. Solomon at MIT (telephone 617-253-3786, facsimile
617-253-1699).
Registration before August 3 through LPI is $40 (students $20).
At the colloquium, registration will be $50 (students $30). A free
public lecture hosted by the Planetary Society will be held on Monday
evening, August 10 at 8:00 PM. Dr. A. T. Basilevsky from the
Vernadsky Institute, of the Russian Academy of Sciences will speak on
"Views of Venus: An Historical Perspective".
Those interested in more information about this colloquium or any
of a broad range of other planetary programs in which the Lunar and
Planetary Institute is involved may use an electronic bulletin board
over the national computer networks. On SPAN (DECNET), set host to
LPI::. On Internet, connect by "telnet" to "lpi.jsc.nasa.gov"
(192.101.147.11). On either network, give the username "lpi". Among
many other topics, this system gives access to the latest announcement
and registration form for the Venus colloguium. It also provides access
to the full set of abstracts for the papers which will be presented.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Most of the things you
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | worry about will never
|_____|/ |_|/ |_____|/ | happen.
|
| 456.497 | Updates - July 27-30 | VERGA::KLAES | Slaves to the Metal Hordes | Fri Jul 31 1992 21:14 | 163 |
| Article: 1553
Newsgroups: sci.space.news
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Subject: Magellan Update - 07/27/92
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Date: Tue, 28 Jul 1992 02:01:38 GMT
Forwarded from the Magellan Project
MAGELLAN STATUS REPORT
July 27, 1992
1. Magellan continues to operate under the M2206 command
sequence, which consists of a starcal (star calibration)
on every orbit and a reaction wheel desaturation on every
other orbit. No radar mapping is being performed.
2. Later today the spacecraft controllers start preliminary
command activity for a test of the transmitter which will
start tomorrow.
3. The objective is to find an operating mode which will
allow radar mapping in early September to fill the only
significant gap in Magellan's global coverage of Venus, a
10-day mapping segment at the end of the cycle.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Most of the things you
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | worry about will never
|_____|/ |_|/ |_____|/ | happen.
Article: 1559
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space.news
Subject: Magellan Update - 07/28/92
Date: 29 Jul 92 01:41:29 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
MAGELLAN STATUS REPORT
July 28, 1992
1. Magellan continues to operate under the M2206 command
sequence, which consists of only starcals (star calibrations)
and desats (desaturations of the reaction wheels). No
radar mapping is being performed.
2. Yesterday spacecraft controllers uplinked commands for a
test of Transmitter B which is being performed today.
3. The objective of the test is to find an operating mode
which will allow radar mapping in early September to fill
the only significant gap in Magellan's global coverage of
Venus, a 10-day mapping segment at the end of the cycle.
Obtaining this coverage would raise the percentage of
Venus surface imaged to about 99%.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Most of the things you
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | worry about will never
|_____|/ |_|/ |_____|/ | happen.
Article: 1577
Newsgroups: sci.space.news
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Subject: Magellan Update - 07/29/92
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Date: Thu, 30 Jul 1992 05:00:45 GMT
Forwarded from the Magellan Project
MAGELLAN STATUS REPORT
July 29, 1992
1. Magellan continues to operate under the M2206 command
sequence, which consists of only starcals (star calibrations)
and desats (desaturations of the reaction wheels). No
radar mapping is being performed.
2. During yesterday's power cycle test of Transmitter B, the
transmitter was turned on near the start of the Goldstone
tracking pass. The transmitter temperature was at 23.4
degrees C as the power cycle test began, and the carrier AGC
(Automatic Gain Control) at DSS-15 (Goldstone 34 meter
antenna) was -140 dB (the predicted value).
3. The purpose was to test a transmitter operating mode in
which the temperature was kept low by turning the
transmitter on only during playback periods. This test
continues today and tomorrow.
4. Magellan scientists are hoping to fill the only
significant gap in Magellan's global coverage of Venus, a
10-day mapping segment at the end of the cycle. Obtaining
this coverage would raise the percentage of Venus surface
imaged to about 99%.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Most of the things you
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | worry about will never
|_____|/ |_|/ |_____|/ | happen.
Article: 1584
Newsgroups: sci.space.news
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Subject: Magellan Update - 07/30/92
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Date: Fri, 31 Jul 1992 02:57:35 GMT
Forwarded from the Magellan Project
MAGELLAN STATUS REPORT
July 30, 1992
1. Magellan continues to operate under the M2206 command
sequence, which consists of only starcals (star
calibrations) and desats (desaturations of the reaction
wheels). No radar mapping is being performed.
2. Yesterday spacecraft controllers repeated the power cycle
test of Transmitter B. This mode replicated the
conditions experienced by the transmitter when is was
first used in January. At that time the performance was
perfect until the temperature reached 30 degrees C, then was
affected by the signal spur.
3. During this week's tests, however, the spur appeared
immediately at turn on, drawing power from the carrier and
preventing the DSN (Deep Space Network) station from locking
onto the signal. This appears to rule out this mode of
operation for mapping in September.
4. Transmitter B has been left on and is being allowed to
continue warming as the telecommunications engineers watch
for a stable regime for transmitting data. During the
period following Superior Conjunction in June, science
data was being received at 115 kbps with the transmitter
at 57 degrees C. Transmitter B is presently at 42.9 degrees C.
5. This effort is directed at filling the only significant
gap in Magellan's global coverage of Venus, a 10-day
mapping segment at the end of the cycle. The prime
mission goal of obtaining global gravity coverage between
September 1992 and May 1993 is not affected by the
transmitter problem because only the X-band carrier signal
is required.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Most of the things you
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | worry about will never
|_____|/ |_|/ |_____|/ | happen.
|
| 456.498 | Updates - July 31 to August 6 | VERGA::KLAES | Slaves to the Metal Hordes | Fri Aug 07 1992 20:24 | 298 |
| Article: 1598
Newsgroups: sci.space.news
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Subject: Magellan Update - 07/31/92
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Date: Sat, 1 Aug 1992 05:53:21 GMT
Forwarded from the Magellan Project
MAGELLAN STATUS REPORT
July 31, 1992
1. Magellan continues to operate under the M2206 command
sequence, which consists of only starcals (star
calibrations) and desats (desaturations of the reaction
wheels). No radar mapping is being performed.
2. Transmitter B has been left on and is being allowed to
continue warming as the telecommunications engineers watch
for a stable regime for transmitting data. Transmitter B
is presently at 42.9 degrees C and warming.
3. The strategy for the near future will be to configure the
spacecraft so as to gradually raise the temperature into
the range of 50 to 60 degrees C. During the period following
Superior Conjunction in June, science data was being
received at 115 kbps with the transmitter at 57 degrees C.
4. This effort is directed at finding a radar operating mode
which will allow filling the only significant gap in
Magellan's global coverage of Venus, a 10-day mapping
segment at the end of the cycle.
5. The prime mission goal of obtaining global gravity
coverage between September 1992 and May 1993 is not
affected by the transmitter problem because only the
X-band carrier signal is required.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Most of the things you
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | worry about will never
|_____|/ |_|/ |_____|/ | happen.
Article: 1619
Newsgroups: sci.space.news
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Subject: Magellan Update - 08/03/92
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Date: Tue, 4 Aug 1992 03:37:05 GMT
Forwarded from the Magellan Project.
MAGELLAN STATUS REPORT
August 3, 1992
1. Magellan continues to operate under the M2206 command
sequence, which consists of only starcals (star calibrations)
and desats (desaturations of the reaction wheels). No
radar mapping is being performed.
2. Transmitter B has been turned off and operations resumed
on Transmitter A. On Friday, controllers alos swapped
from Receiver A to B to allow a gradual cool down of
Transmitter B.
3. The strategy to configure the spacecraft so as to
gradually raise the temperature into the range of 50 to 60
degrees C when Transmitter B is turned back on in late
August. Only the hot mode of operation can be used since
last week's test ruled out the cold/power cycling mode.
4. This effort is directed at finding a radar operating mode
which will allow filling the only significant gap in
Magellan's global coverage of Venus, a 10-day mapping
segment at the end of the cycle.
5. The prime mission goal of obtaining global gravity
coverage between September 1992 and May 1993 is not
affected by the transmitter problem because only the X-
band carrier signal is required.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | You can't hide brocolli in
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | a glass of milk -
|_____|/ |_|/ |_____|/ | anonymous 7-year old.
Article: 1633
Newsgroups: sci.space.news
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Subject: Magellan Update - 08/04/92
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Date: Wed, 5 Aug 1992 01:53:01 GMT
MAGELLAN STATUS REPORT
August 4, 1992
1. Magellan continues to operate under the M2206 command
sequence, which consists of only starcals (star calibrations)
and desats (desaturations of the reaction wheels). No
radar mapping is being performed.
2. Transmitter B has been turned off and operations resumed
on Transmitter A.
3. When Transmitter B is turned back on in late August, the
spacecraft controllers are planning to configure the
spacecraft so as to gradually raise the temperature into
the range of 50 to 60 degrees C. Only the hot mode of
operation can be used since last week's test ruled out the
cold/power cycling mode. The present plan is to perform
left-look radar mapping from September 3 to the end of
Cycle 3 on September 14.
4. Then Magellan will be commanded to perform an Orbit Trim
Maneuver (OTM) to lower the periapsis. This increases the
effect of gravitational variations as the spacecraft
passes close to Venus. The Magellan mission will focus on
obtaining global gravity coverage between September 1992
and May 1993.
5. Magellan has explored Venus for 726 days and has orbitted
the planet 5340 times. The spacecraft has performed radar
mapping on 4417 orbits or 82.6% of the total. The radar
images cover 97.5% of the total surface area.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | You can't hide broccoli in
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | a glass of milk -
|_____|/ |_|/ |_____|/ | anonymous 7-year old.
Article: 1645
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space.news
Subject: Magellan Update - 08/05/92
Date: 6 Aug 92 02:33:21 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from:
PUBLIC INFORMATION OFFICE
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIF. 91109. TELEPHONE (818) 354-5011
MAGELLAN STATUS REPORT
August 5, 1992
Two tests were conducted on Magellan's transmitter B last
week at its minimum temperature of 23.4 C (74 F) to see if high
rate data could be received. Both tests showed a continuing
noise spur at various temperatures which has prevented the
transmission back to Earth of mapping data with transmitter B in
the low temperature mode. The alternate transmitter, A, failed
last January.
It was thought that turning the transmitter off and
permitting it to cool until needed would prevent the noise spur
from occurring. Since it was not successful, controllers said,
the project will return to the mode of leaving the transmitter on
when it resumes testing on August 21. That command sequence,
which runs until September 3, will be a dress rehearsal and high
temperature stabilization period for the next sequence, September
3 to 14, designed to map the last significant coverage gap, about
1.5 percent, in the global map of Venus.
In the meantime, transmitter B has been turned off and daily
operations have been resumed on transmitter A which can be used
for gravity and engineering data. The orbit adjustment burn to
reduce periapsis altitude to 182.5 kilometers (113.15 miles) is
still planned for September 14, marking the beginning of cycle 4.
That cycle will be dedicated to global gravity data with some
targeted mapping. Both transmitters can be used for gravity
mission operations, but only transmitter B can be used for mapping.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | You can't hide broccoli in
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | a glass of milk -
|_____|/ |_|/ |_____|/ | anonymous 7-year old.
Article: 1646
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space.news
Subject: Magellan Update #2 - 08/05/92
Date: 6 Aug 92 02:36:22 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from the Magellan Project
MAGELLAN STATUS REPORT
August 5, 1992
1. Magellan continues to operate normally, performing only
starcals (star calibrations) and desats (desaturations of
reaction wheels).
2. When Transmitter B is turned back on in late August, the
spacecraft controllers are planning to gradually raise the
temperature into the range of 50 to 60 degrees C, watching
for a hot but stable mode of operation. The present plan
is to perform left-look radar mapping from September 3 to
September 14, and for several targetted areas during the
first half of Cycle 4.
3. Magellan will be commanded to perform an Orbit Trim
Maneuver (OTM) to lower the periapsis in September. This
increases the effect of gravitational variations as the
spacecraft passes close to Venus. The Magellan mission
will focus on obtaining global gravity coverage between
September 1992 and May 1993.
4. Magellan has explored Venus for 726 days and has orbitted
the planet 5340 times. The spacecraft has performed radar
mapping on 4417 orbits or 82.6% of the total. The radar
images cover 97.5% of the total surface area.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | You can't hide broccoli in
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | a glass of milk -
|_____|/ |_|/ |_____|/ | anonymous 7-year old.
Article: 1657
Newsgroups: sci.space.news
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Subject: Magellan Update - 08/06/92
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Date: Fri, 7 Aug 1992 02:15:32 GMT
Forwarded from the Magellan Project
MAGELLAN STATUS REPORT
August 6, 1992
1. Magellan continues to operate normally, performing only
starcals (star calibrations) and desats (desaturations
of the reaction wheels).
2. Today controllers plan to send a non-standard command to
turn off DMS-A (tape recorder in the Data Management
Subsystem), then later in the day the M2220 command sequence.
This sequence will be essentially the same as M2206,
performing only starcals and desats.
3. The status of Magellan will remain unchanged until about
August 21 when Transmitter B will be turned on and
configured for the "warm-stable' mode of operation.
4. As part of the International Colloquium on Venus being
held at Caltech next week, Dr. Alexander Basilevsky will
give a public presentation, "Some Like It Hot! - A History
of Venus Exploration." Basilevsky is a Magellan guest
investigator from the Vernadsky Institute, and has been
involved in the Russian lunar and planetary program since
1968. The free presentation will be on Monday, August 10
at 8 pm in Ramo Auditorium, Caltech.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | You can't hide broccoli in
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | a glass of milk -
|_____|/ |_|/ |_____|/ | anonymous 7-year old.
Article: 1665
Newsgroups: sci.space.news
From: yee@trident.arc.nasa.gov (Peter E. Yee)
Subject: Currently mounted CD-ROMs in the Ames SPACE Archive
Sender: usenet@news.arc.nasa.gov
Organization: NASA Ames Research Center, Moffett Field, CA
Date: Fri, 7 Aug 1992 08:28:11 GMT
I've just mounted Magellan, volumes 32 and 33 in the Ames SPACE
Archive. Now that I'm out of other new discs, this I will be loading
Magellan at a rate of 2 per week in an attempt to catch up. Lucky for
me, Magellan is not transmitting science data at the moment, so I may
actually make it. Not so good for Magellan though. I've got the
Magellan discs through volume 48. Hopefully, one of these days, my
order for 14 Pioneer 6 platter CD-ROM drives will go through. Then I
hope to have 84 discs on-line simultaneously. Holding my breath!
-Peter Yee
yee@atlas.arc.nasa.gov
|
| 456.499 | Updates - August 7-14 | VERGA::KLAES | Slaves to the Metal Hordes | Fri Aug 14 1992 20:55 | 123 |
| Article: 1673
Newsgroups: sci.space.news
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Subject: Magellan Update - 08/07/92
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Date: Sat, 8 Aug 1992 08:05:22 GMT
Forwarded from the Magellan Project
MAGELLAN STATUS REPORT
August 7, 1992
1. Magellan continues to operate normally, performing only
starcals (star calibrations) and desats (desaturations
of the reaction wheels).
2. The M2220 command sequence was uplinked yesterday and
begins execution today at a minute before 11 am. This
sequence is essentially the same as M2206, performing only
starcals and desats.
3. The status of Magellan will remain unchanged until August
21 when Transmitter B will be turned on and radar mapping
is attempted in the "warm-stable' mode of operation.
4. Magellan team members, their spouses and friends will want
to attend the free public audio-visual presentation by Dr.
Alexander Basilevsky of the Vernadsky Institute titled
"Some Like It Hot! - A History of Venus Exploration."
Basilevsky is a Magellan guest investigator and has been
involved in Russian lunar and planetary missions since
1968. The presentation will be on Monday, August 10 in
Ramo Auditorium, Caltech. Doors open at 7:45 pm.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | You can't hide broccoli in
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | a glass of milk -
|_____|/ |_|/ |_____|/ | anonymous 7-year old.
Article: 1705
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space.news
Subject: Magellan Update - 08/13/92
Date: 14 Aug 92 04:30:57 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from the Magellan Project
MAGELLAN STATUS REPORT
August 13, 1992
1. Magellan continues to operate normally, performing only
starcals (star calibrations) and desats (desaturations of
the reaction wheels).
2. A week from now, Transmitter B will be turned back on and
the temperature gradually raised into the range of 50 to
60 degrees C. It is hoped that this operating mode which
will allow the return of radar data at 115 kbps in order
to fill the only significant gap in Magellan's global
coverage of Venus.
3. The critical period, a 10-day mapping segment at the end
of the cycle, begins on September 3 and is included in the
M2247 command sequence.
4. The International Colloquium on Venus was concluded
yesterday at Caltech. The meeting included over 120
technical papers on Venus research, many based on Magellan
data. The colloquium ended with six "summarizers" who
emphasized the areas for further Venus research and a
panel discussion of prospects for future missions. It was
generally agreed that the highest priority was for a
continuation of the Magellan mission and continued funding
for research using the Magellan data.
5. Magellan has explored Venus for 734 days.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | You can't hide broccoli in
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | a glass of milk -
|_____|/ |_|/ |_____|/ | anonymous 7-year old.
Article: 1710
Newsgroups: sci.space.news
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Subject: Magellan Update - 08/14/92
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Date: Sat, 15 Aug 1992 02:20:16 GMT
Forwarded from the Magellan Project
MAGELLAN STATUS REPORT
August 14, 1992
1. Magellan continues to operate normally, performing only
starcals (star calibrations) and desats (desaturations of
the reaction wheels).
2. The Magellan Project Science Group is meeting today at
JPL, reviewing plans for Cycle 4 and continued studies of
the Magellan data.
3. The second anniversary of Magellan's arrival at Venus
passed somewhat quietly on Monday. Attention was focussed
on the International Colloquium on Venus and the giant
leap in our knowledge of the planet which has resulted
from the Magellan mission.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | You can't hide broccoli in
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | a glass of milk -
|_____|/ |_|/ |_____|/ | anonymous 7-year old.
|
| 456.500 | Updates - August 14-20 | VERGA::KLAES | Slaves to the Metal Hordes | Fri Aug 21 1992 22:07 | 200 |
| Article: 1710
Newsgroups: sci.space.news
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Subject: Magellan Update - 08/14/92
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Date: Sat, 15 Aug 1992 02:20:16 GMT
Forwarded from the Magellan Project
MAGELLAN STATUS REPORT
August 14, 1992
1. Magellan continues to operate normally, performing only
starcals (star calibrations) and desats (desaturations of
the reaction wheels).
2. The Magellan Project Science Group is meeting today at
JPL, reviewing plans for Cycle 4 and continued studies of
the Magellan data.
3. The second anniversary of Magellan's arrival at Venus
passed somewhat quietly on Monday. Attention was focussed
on the International Colloquium on Venus and the giant
leap in our knowledge of the planet which has resulted
from the Magellan mission.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | You can't hide broccoli in
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | a glass of milk -
|_____|/ |_|/ |_____|/ | anonymous 7-year old.
Article: 1733
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space.news
Subject: Magellan Update - 08/17/92
Date: 18 Aug 92 08:02:38 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from the Magellan Project
MAGELLAN STATUS REPORT
August 17, 1992
1. Magellan continues to operate normally, performing only
starcals (star calibrations) and desats (desaturations
of the reaction wheels).
2. The spacecraft experienced another spurious shutoff of the
TWTA (Traveling Wave Tube Amplifier) on Saturday, but the
on-board fault protection quickly restored communications.
3. The mission is now in the final week of this non-mapping
mode. When the M2234 command sequence starts on Friday,
Transmitter B will be turned on and allowed to warm to the
range of 50-60 degrees C.
4. It is hoped that this will result in an operating mode
which permits high-rate science data to be received on Earth
as was the case just after Superior Conjunction in June.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Optimists live longer
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | than pessimists.
|_____|/ |_|/ |_____|/ |
Article: 1736
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space.news
Subject: Magellan Update - 08/18/92
Date: 19 Aug 92 01:51:02 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from the Magellan Project
MAGELLAN STATUS REPORT
August 18, 1992
1. Magellan continues to operate normally, performing only
starcals (star calibrations) and desats (desaturations
of the reaction wheels).
2. The spacecraft spends a portion of each orbit in solar and
Earth occultation, that is, in the shadow of Venus and
behind the planet as viewed from Earth. Earth
occultations have now peaked at 23 minutes and will
diminish between now and September 14.
3. When Magellan comes out of Earth occultation season
and begins Cycle 4, we will have a full cycle of 243 days
in which periapsis - the part of the orbit closest to
Venus - is visible from Earth. This is the ideal
condition for gathering gravity data because the
gravitational effects are most pronounced near periapsis.
4. However, before we enter Cycle 4 we are hoping to gather
radar image data for 10 days in early September to fill
the one significant gap in surface coverage.
5. If a satisfactory radar operating mode is found, mission
planners have retained the option of performing some
imaging of selected target areas during Cycle 4.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Optimists live longer
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | than pessimists.
|_____|/ |_|/ |_____|/ |
Article: 1746
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space.news
Subject: Magellan Update - 08/19/92
Date: 20 Aug 92 04:57:06 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from the Magellan Project
MAGELLAN STATUS REPORT
August 19, 1992
1. Magellan continues to operate normally, performing only
starcals (star calibrations) and desats (desaturations
of the reaction wheels).
2. Tomorrow the M2234 command sequence will be uplinked to
the spacecraft. During this sequence, Transmitter B will
be turned on and the "hot stable" mode of operation tested.
3. The spacecraft spends a portion of each orbit in solar and
Earth occultation, that is, in the shadow of Venus and
behind the planet as viewed from Earth. The Earth
occultations are now 22 minutes and diminishing. The
solar occultations will end tomorrow.
4. Magellan guest investigator Sasha Basilevsky and science
team member Cathy Weitz are presenting a Lab-wide science
seminar today at 10 am in von Karman auditorium.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Optimists live longer
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | than pessimists.
|_____|/ |_|/ |_____|/ |
Article: 1750
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space.news
Subject: Magellan Update - 08/20/92
Date: 21 Aug 92 05:24:58 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from the Magellan Project
MAGELLAN STATUS REPORT
August 20, 1992
1. Magellan continues to operate normally, performing only
starcals (star calibrations) and desats (desaturation
of the reaction wheels).
2. Later today the M2234 command sequence will be uplinked to
the spacecraft. During this sequence, Transmitter B will
be turned on and the "hot stable" mode of operation tested
in preparation for the M2247 sequence when we plan to fill
one of the few remaining gaps in surface image coverage.
3. The spacecraft spends a portion of each orbit in solar and
Earth occultation, that is, in the shadow of Venus and
behind the planet as viewed from Earth. The Earth
occultations are now 22 minutes and diminishing. The
solar occultations will end early this afternoon.
4. Yesterday's Lab-wide Science briefing by Russian guest
investigator Sasha Basilevsky and science team member
Cathy Weitz was well received. Basilevsky presented
surface composition and images from the Venera and Vega
landers, and Weitz showed Magellan images and geologic
maps corresponding to each landing area. Four of the six
spacecraft apparently landed on the smooth basaltic
plains, while Veneras 8 and 13 landed on somewhat altered
basalts (perhaps even one of the pancake domes).
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Optimists live longer
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | than pessimists.
|_____|/ |_|/ |_____|/ |
|
| 456.501 | Status Reports - August 21-25 | PRAGMA::GRIFFIN | Dave Griffin | Wed Aug 26 1992 13:49 | 83 |
| Magellan Status
Status report of Magellan for Friday, August 21, 1992:
1. Magellan continues to operate normally, performing only starcals and
desats.
2. The M2234 command sequence was uplinked to the spacecraft yesterday and
began execution at 7:06 AM PDT. During this sequence, Transmitter B will be
turned on and the "hot stable" mode of operation tested in preparation for
the M2247 sequence when we plan to fill one of the few small remaining gaps
in surface image coverage.
3. Magellan has completed 743 days at Venus, orbiting the planet 5465 times
and mapping over 97% of the surface.
------------------------------------------------------------------------------
Magellan Status
Status report of Magellan for Monday, August 24, 1992:
1. Magellan continues to operate normally, performing only
starcals and desats. All starcals over the weekend were
successful, with two partially successful.
2. Since the M2234 command sequence began execution on
Friday, spacecraft temperatures have followed their
predicted values. The new sequence includes two "heats,"
periods in each orbit when the spacecraft is placed in an
attitude to warm portions of the spacecraft.
3. Magellan is presently operating on Transmitter A, which is
at 51.8 deg. C. The electronic equipment bays 7 through
10 are at 53.5 to 65.9 deg C. These temperatures are
within the predicted range for this phase of the sequence.
4. The radar is currently in standby mode and will be turned
"on" this Wednesday. That is, the radar transmitter will
send out pulses of energy. No mapping will be attempted.
The prime purpose is to find a hot, stable mode of
operation.
5. Controller plan to switch from Transmitter A to B on
Thursday, and will closely monitor the signal spur as the
transmitter temperature rises into the mid-50's.
6. If all goes well, Magellan will resume mapping during the
M2247 sequence which begins September 3rd.
-------------------------------------------------------------------------------
Magellan Status
Status report of Magellan for Tuesday, August 25, 1992:
1. Magellan continues to operate normally, performing only
starcals and desats. The present command sequence
includes radar mapping commands, but the radar system
remains in standby mode.
2. The principal activity for this week is to gradually warm
the transmitter to a stable operating mode. The sequence
includes two "heat" periods in each orbit when the
spacecraft is placed in an attitude to warm portions of
the spacecraft.
3. The radar will be turned "on" tomorrow and a swap from
Transmitter A to B on Thursday. Then controllers will
closely monitor the signal spur as the transmitter
temperature rises into the mid-50's. If all goes well,
Magellan will resume mapping during the M2247 sequence
which begins September 3rd.
4. Yesterday the Magellan Project hosted 18 students and 4
teachers of the "Space Ship Dunbar" from Dunbar High
School in Washington, D.C. After a status update from
Doug Griffith, Project Manager, the group participated in
a Venus geology exercise led by Jeff Plaut. After their
visit at JPL the group had a barbeque and swim party at
Phil Allin's, with the food donated by various Magellan
team members.
|
| 456.502 | Updates - August 24-28 | VERGA::KLAES | All the Universe, or nothing! | Tue Sep 01 1992 19:34 | 238 |
| Article: 1785
Newsgroups: sci.space.news
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Subject: Magellan Update - 08/24/92
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Date: Tue, 25 Aug 1992 02:34:22 GMT
Forwarded from the Magellan Project
MAGELLAN STATUS REPORT
August 24, 1992
1. Magellan continues to operate normally, performing only
starcals (star calibrations) and desats (desaturation
of the reaction wheels). All starcals over the weekend were
successful, with two partially successful.
2. Since the M2234 command sequence began execution on
Friday, spacecraft temperatures have followed their
predicted values. The new sequence includes two "heats,"
periods in each orbit when the spacecraft is placed in an
attitude to warm portions of the spacecraft.
3. Magellan is presently operating on Transmitter A, which is
at 51.8 degrees C. The electronic equipment bays 7 through
10 are at 53.5 to 65.9 degrees C. These temperatures are
within the predicted range for this phase of the sequence.
4. The radar is currently in standby mode and will be turned
"on" this Wednesday. That is, the radar transmitter will
send out pulses of energy. No mapping will be attempted.
The prime purpose is to find a hot, stable mode of operation.
5. Controller plan to switch from Transmitter A to B on
Thursday, and will closely monitor the signal spur as the
transmitter temperature rises into the mid-50's.
6. If all goes well, Magellan will resume mapping during the
M2247 sequence which begins September 3rd.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Optimists live longer
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | than pessimists.
|_____|/ |_|/ |_____|/ |
Article: 1781
Newsgroups: sci.space.news
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Subject: Magellan Update - 08/25/92
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Date: Wed, 26 Aug 1992 07:02:32 GMT
Forwarded from the Magellan Project
MAGELLAN STATUS REPORT
August 25, 1992
1. Magellan continues to operate normally, performing only
starcals (star calibrations) and desats (desaturation of
the reaction wheels). The present command sequence includes
radar mapping commands, but the radar system remains in
standby mode.
2. The principal activity for this week is to gradually warm
the transmitter to a stable operating mode. The sequence
includes two "heat" periods in each orbit when the
spacecraft is placed in an attitude to warm portions of
the spacecraft.
3. The radar will be turned "on" tomorrow and a swap from
Transmitter A to B on Thursday. Then controllers will
closely monitor the signal spur as the transmitter
temperature rises into the mid-50's. If all goes well,
Magellan will resume mapping during the M2247 sequence
which begins September 3rd.
4. Yesterday the Magellan Project hosted 18 students and 4
teachers of the "Space Ship Dunbar" from Dunbar High
School in Washington, D.C. After a status update from
Doug Griffith, Project Manager, the group participated in
a Venus geology exercise led by Jeff Plaut. After their
visit at JPL the group had a barbeque and swim party at
Phil Allin's, with the food donated by various Magellan
team members.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Optimists live longer
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | than pessimists.
|_____|/ |_|/ |_____|/ |
Article: 1787
Newsgroups: sci.space.news
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Subject: Magellan Update - 08/26/92
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Date: Thu, 27 Aug 1992 05:30:48 GMT
Forwarded from the Magellan Project
MAGELLAN STATUS REPORT
August 26, 1992
1. Magellan continues to operate normally, performing only
starcals (star calibrations) and desats (desaturation
of the reaction wheels).
2. Today the radar will be turned on and will radiate pulses.
The purpose of this step is to gradually warm electronic
components in preparation for radar mapping in early September.
3. Tomorrow a swap from Transmitter A to B will be
commanded, and controllers will closely monitor the signal
spur as the transmitter temperature rises into the mid-50s.
4. The Magellan telecommunications engineers are trying to
establish a stable operating mode for the transmitter
which will allow the recovery of radar image data from an
area of Venus south of the equator between 284 and 330
degrees longitude.
5. Among the major features of this area are Ushas Mons,
Innini Mons, and Hathor Mons, three mountains west of
Alpha Regio.
6. This area was missed on Cycle 1 because the radar swaths
had to be shortened for thermal control. It was missed
during Cycle 2 because Transmitter A lost its subcarrier
modulation capability and we had to swap to Transmitter B
and find a solution to its signal spur.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Optimists live longer
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | than pessimists.
|_____|/ |_|/ |_____|/ |
Article: 1795
Newsgroups: sci.space.news
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Subject: Magellan Update - 08/27/92
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Date: Fri, 28 Aug 1992 04:21:38 GMT
Forwarded from the Magellan Project
MAGELLAN STATUS REPORT
August 27, 1992
1. Magellan continues to operate normally, performing radar
mapping maneuvers and collecting data on its tape
recorder, as well as the routine starcals (star calibrations)
and desats (desaturation of the reaction wheels).
2. The spacecraft experienced another spurious shutoff of the
TWTA (Traveling Wave Tube Amplifier) this morning, but the
on-board fault protection quickly restarted the high power
amplifier.
3. A swap from Transmitter A to B was commanded at 8:26 AM
PDT, and controllers are closely monitoring the signal
spur as the transmitter temperature rises.
4. The telecommunications engineers are trying to establish a
stable operating mode for the transmitter which will allow
the recovery of radar image data. So the next few days will
be critical for determining our capability for radar mapping.
5. Among the major features in the area to be mapped are
Ushas Mons, Innini Mons, and Hathor Mons, three mountains
west of Alpha Regio. This area was missed on Cycle 1
because the radar swaths were shortened by the "two-hide"
strategy for thermal control. It was missed during Cycle
2 because Transmitter A lost its subcarrier modulation
capability and we had to swap to Transmitter B and find a
solution to its signal spur.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Optimists live longer
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | than pessimists.
|_____|/ |_|/ |_____|/ |
Article: 1802
Newsgroups: sci.space.news
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Subject: Magellan Update - 08/28/92
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Date: Sat, 29 Aug 1992 02:37:54 GMT
Forwarded from the Magellan Project
MAGELLAN STATUS REPORT
August 28, 1992
1. Magellan continues to operate normally, performing radar
mapping maneuvers and routine starcals (star calibrations)
and desats (desaturation of the reaction wheels).
2. Following the swap from Transmitter A to B yesterday, the
transmitter warmed from 33 to 57.5 degrees C. During this
phase the receiver AGC (Automatic Gain Control) at the DSN
(Deep Space Network) stations remained at -142 dn. In
order to successfully receive radar image data at 115 kbps
the AGC needs to improve to -135 dn or higher.
3. This morning the spacecraft controllers plan to turn on
the 360 kHz subcarrier for about 30 minutes to obtain
spectrum plots of the modulated signal. Commands to
increase the radar heater set points to raise the
temperatures another 1.5 degrees will be sent later today.
4. The commands to turn on the 360kHz subcarrier for 30
minutes will be repeated tomorrow. No further tests or
commanding are planned until Monday, when power cycling of
the transmitter may be performed.
5. The Spacecraft Team is continuing to search for a
satisfactory operating mode which will allow radar mapping
of an area southwest of Alpha Regio.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Optimists live longer
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | than pessimists.
|_____|/ |_|/ |_____|/ |
|
| 456.503 | | DECWIN::FISHER | I *hate* questionnaires--Worf | Fri Sep 11 1992 16:18 | 4 |
| Anyone heard if they found the "hot stable" mode, and if they were able to map
the previously missing area?
Burns
|
| 456.504 | | DECWIN::FISHER | I *hate* questionnaires--Worf | Tue Sep 15 1992 16:15 | 6 |
| This week's AvWeek indicates in a brief paragraph that they did successfully
start mapping last week to get the last major gap covered. They were scheduled
to turn off mapping yesterday (I think). That may be the last radar mapping
done my Magellan.
Burns
|
| 456.505 | Magellan Begins Gravity Mapping | CXDOCS::J_BUTLER | E poi, si muove... | Wed Sep 16 1992 18:33 | 83 |
| Article 1958 of sci.space.news:
Newsgroups: sci.space.news
Path: nntpd2.cxo.dec.com!nntpd.lkg.dec.com!news.crl.dec.com!deccrl!caen!uakari.primate.wisc.edu!ames!dont-send-mail-to-path-lines
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Subject: Magellan Begins Gravity Mapping of Venus
Message-ID: <1992Sep15.203749.11882@news.arc.nasa.gov>
Followup-To: sci.space
News-Software: VAX/VMS VNEWS 1.3-4
Keywords: Magellan, JPL
Sender: news@elroy.jpl.nasa.gov (Usenet)
Nntp-Posting-Host: kelvin.jpl.nasa.gov
Reply-To: baalke@kelvin.jpl.nasa.gov
Organization: Jet Propulsion Laboratory
Date: Wed, 16 Sep 1992 04:36:31 GMT
Approved: sci-space-news@ames.arc.nasa.gov
Lines: 64
Michael Braukus
Headquarters, Washington, D.C. September 15, 1992
(Phone: 202/358-1547)
Jim Doyle
Jet Propulsion Laboratory, Pasadena, Calif.
(Phone: 818/354-5011)
RELEASE: 92-148
NASA SPACECRAFT BEGINS GRAVITY MAPPING OF VENUS
The Magellan spacecraft's orbit at its closest approach
to Venus was lowered Monday and today it began a full 243-
day cycle of gravity mapping, project officials at NASA's
Jet Propulsion Laboratory, Pasadena, Calif., said.
Magellan has now completed three cycles of mapping
with its radar, covering 99 percent of the surface of
Venus. Monday, controllers ordered a 1-hour orbit
adjustment burn to lower its periapsis -- closest approach
to the planet -- altitude from 160 miles (258 kilometers)
to 113 miles (182 kilometers).
"That will help us obtain the best possible resolution
in the equatorial latitude gravity map," Project Manager
Doug Griffith said.
The objective of cycle 4, which extends to May 15,
1993, is to obtain a global map of the Venus gravity field
from the elliptical orbit. The orbit apoapsis, or furthest
point from the planet, remains the same, 5,296 miles (8,543
kilometers).
During this fourth cycle, variations in the
gravitational pull experienced by the spacecraft are being
recorded by carefully tracking the Doppler shift of a radio
signal that Magellan will constantly beam to the Deep Space
Network tracking stations.
When Magellan passes over a dense region of Venus'
interior, for example, the spacecraft accelerates in its
orbit and the location of the denser region is mapped.
Over the course of the 243-day cycle, one rotation of
Venus, variations in the planet's density will be mapped at
a resolution much higher than achieved by previous
missions.
Looking at the interior with gravity observations is
expected to provide an improved understanding of the forces
of tectonics and volcanism that shape the planet.
Magellan is managed by the Jet Propulsion Laboratory
for NASA's Office of Space Science and Applications,
Washington, D.C.
- end -
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Quiet people aren't the
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | only ones who don't say
|_____|/ |_|/ |_____|/ | much.
|
| 456.506 | Magellan Status - 9/14/92 - 9/16/92 | PRAGMA::GRIFFIN | Dave Griffin | Thu Sep 17 1992 12:51 | 64 |
|
Magellan Status
Status report of Magellan for Monday, September 14, 1992:
1. Magellan completed the latest radar mapping operations
over the weekend bringing total Venus mapped area to 99
percent of the planet. The radar has been put in standby
mode to prepare for gravity operations.
2. Early Monday morning, 14 September, final spacecraft
configuration changes were made for the orbit trim
maneuver (OTM) to be performed between 12:54 and 01:48 pm
PDT. The OTM is targeted to lower the orbit periapsis
altitude from 258 to 182 kilometers. This will enhance
gravity data collection for the beginning of Cycle-4 on
15 September 1992.
---------------------------------------------------------------------------
Magellan Status
Status report of Magellan for Tuesday, September 15, 1992:
1. Magellan successfully performed a major Orbit Trim Maneuver (OTM)
yesterday. A 54 minute thruster burn lowered Magellan's periapsis from
258 kilometers to 184.7 kilometers. The telemetered data indicates the
burn was accurate to about one percent, but the final altitude
corresponds to a 3% underburn. Results are well within expected error
limits.
2. Gravity science data collection is currently underway, marking the
beginning of the predominant activity of Cycle 4.
---------------------------------------------------------------------------
Magellan Status
Status report of Magellan for Wednesday, September 16, 1992:
1. Magellan continues to operate normally, following its
successful orbit trim maneuver on Monday. The radar
system will remain in standby mode until later in Cycle 4
2. Later today the M2261 command sequence will be sent to the
spacecraft. This includes a one-week battery
reconditioning similar to one performed at the start of
Cycle 3 last January
3. The primary science activity from now to the end of Cycle
4 on May 15, 1993 will be the collection of very precise
tracking data from which gravity measurements can be
extracted.
4. By studying the extremely subtle variations in Magellan's
orbit, scientists can map the density distribution of
Venus, correlate the variations of mass with surface
features, and model the possible internal structure of the
planet.
|
| 456.507 | Magellan Status - 9/17/92, 9/21/92 | PRAGMA::GRIFFIN | Dave Griffin | Tue Sep 22 1992 17:08 | 67 |
| Magellan Status
Status report of Magellan for Thursday, September 17, 1992:
1. Magellan continues to operate normally, performing only
starcals and desats as the spacecraft begins a week-long
battery reconditioning sequence.
2. The battery reconditioning sequence was successfully
uplinked to the spacecraft yesterday.
3. Early this morning, on orbit #5772, the spacecraft
experienced a triple spurius shutoff (SSO) of the TWTA.
On-board fault protection quickly restored normal
operations, but express commands were needed to turn off
the 360 kHz subcarrier which is not being used during
present operations.
4. Yesterday's playback of tape recorded engineering data
from Monday's orbit trim maneuver and other spacecraft
telemetry was unsuccessful due to the inability of the DSN
stations to lock up to the spacecraft signal. This is a
result of the cooling of Transmitter B following the 10-
day mapping period which ended September 13.
5. Primary science activity from now to the end of Cycle 4 on
May 15, 1993 will be the collection of very precise
doppler tracking data from which gravity measurements can
be extracted.
---------------------------------------------------------------------------
Magellan Status
Status report of Magellan for Monday, September 21, 1992:
1. Magellan continues to operate normally, performing the
battery reconditioning sequence.
2. The reconditioning sequence on battery #1 was completed
over the weekend. The battery achieved a 96% depth of
discharge, with the battery voltage at 23.2 volts. This
is somewhat better than the first battery reconditioning
in January 1992. On Sunday morning, battery #1 was
reconnected to the spacecraft electrical bus.
3. Command to reconfigure the power system relays for
reconditioning battery #2 were uplinked this morning and
the start of the discharge process was confirmed. The
reconditioning of battery #2 will be completed by
Wednesday.
4. Late yesterday the spacecraft experienced another TWTA
SSO. The on-board fault protection quickly returned the
telecommunication system to its normal state. This
required controllers to send an express command to turn
off the high rate subcarrier.
5. Since the 360kHz subcarrier will not be needed for gravity
data collection through the end of Cycle 4, controllers
are planning to change the fault protection later this
week so that the spacecraft will return to "Carrier only
plus X-band telemetry" in the event of a TWTA SSO.
6. Spacecraft temperatures remain in the expected range
(slightly warming) and there were three partially
successful starcals over the weekend. Starcals and desats
are performed on every 3.2-hour orbit.
|
| 456.508 | Updates - September 22-23; atlas info | VERGA::KLAES | All the Universe, or nothing! | Thu Sep 24 1992 16:52 | 229 |
| Article: 1901
Newsgroups: sci.space.news
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Subject: Magellan Science Results Published
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Date: Fri, 11 Sep 1992 14:52:07 GMT
The "Journal of Geophysical Research - Planets" has dedicated two issues
of their journal to the science results of the Magellan mission. I
have just received Part 1 today in the mail (Volume 97, Number E8, dated
August 25, 1992). This hefty issue consists of 27 articles and over
600 pages.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Anything is impossible if
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | you don't attempt it.
|_____|/ |_|/ |_____|/ |
Article: 1916
Newsgroups: sci.space.news
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Subject: Magellan Caption Files
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Date: Mon, 14 Sep 1992 23:31:54 GMT
==========================
MAGELLAN CAPTION FILES
September 14, 1992
==========================
An updated version of the caption files for the Magellan images is now
available. These files contain descriptions of the public released Venus
images taken by the Magellan spacecraft. The caption files are provided in
four formats: ASCII format, IBM Wordperfect 5.1 format, IBM Word
format, and a Macintosh Word format compressed with the Stuffit program
(MacBinary format). The files are available using anonymous ftp at:
ftp: ames.arc.nasa.gov (128.102.18.3)
user: anonymous
cd: pub/SPACE/MAGELLAN/CAPTIONS
files: captions.txt (ASCII)
caps_txt.zip (ASCII -> PKZIP)
caps_wp5.zip (IBM PC Wordperfect 5.1 -> PKZIP)
caps_wrd.zip (IBM PC Word -> PKZIP)
captions.sit (Macintosh Word -> Stuffit)
Each caption refers to a P number. By using this P number you can
obtain the corresponding photograph from one of the following places:
Newell Color Lab
221 N. Westmoreland Avenue
Los Angeles CA 90064
Telephone: (213) 380-2980
Fax: (213) 739-6984
OR
National Space Science Data Center
Goddard Space Flight Center
Greenbelt, Maryland 20771
Telephone: (301) 286-6695
Email address: request@nssdca.gsfc.nasa.gov
#####
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Anything is impossible if
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | you don't attempt it.
|_____|/ |_|/ |_____|/ |
Article: 2027
Newsgroups: sci.space.news
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Subject: Magellan Update - 09/22/92
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Date: Wed, 23 Sep 1992 03:39:46 GMT
Forwarded from the Magellan Project
MAGELLAN STATUS REPORT
September 22, 1992
1. Magellan continues to operate normally, performing the
battery reconditioning sequence.
2. Commands to reconfigure the power system relays for
reconditioning battery #2 were uplinked yesteray morning
and the 55-hour discharge process was started. The
reconditioning of battery #2 will be completed by tomorrow.
3. In the next few days controllers are planning to change
the fault protection routines which handle recovery from a
spurious shutoff of the Traveling Wave Tube Amplifier
(TWTA). Since the 360kHz subcarrier will not be needed
for gravity data collection through the end of Cycle 4,
the spacecraft will return to "Carrier only plus X-band
telemetry" in the event of a TWTA SSO.
4. The next command sequence will be uplinked on Friday.
Through most of the mission-to-date the sequences have
been prefixed with an "M" to denote a Mapping sequence.
During Cycle 4, the letter "G" will be used to denote
Gravity data collection. The letter is followed by a
digit denoting the year, i.e. "2" (for 1992), and the day-
of-year, i.e. 269. Thus the next command sequence is G2269.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Quiet people aren't the
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | only ones who don't say
|_____|/ |_|/ |_____|/ | much.
Article: 2033
Newsgroups: sci.space.news
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Subject: Magellan Update - 09/23/92
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Date: Thu, 24 Sep 1992 03:08:33 GMT
Forwarded from the Magellan Project
MAGELLAN STATUS REPORT
September 23, 1992
1. Magellan continues to operate normally, performing the
battery reconditioning sequence.
2. The discharge process on battery #2 is continuing and
should be completed shortly before 4 PM PDT this
afternoon. After a recharging period lasting about 6
hours, the battery will be reconnected to the spacecraft
electrical bus. The present voltages of both batteries
are in the expected range.
3. This morning controllers have uplinked commands to change
the fault protection routines which handle recovery from a
spurious shutoff of the Traveling Wave Tube Amplifier
(TWTA). Since the 360kHz subcarrier will not be needed
for gravity data collection through the end of Cycle 4,
the spacecraft will return to "Carrier only plus X-band
telemetry" in the event of a TWTA SSO.
4. The primary science data being gathered during Magellan's
Cycle 4 is gravimetric measurements, i.e. fluctuations in
the orbit caused by variations in the local density of
Venus. These measurements have a resolution of about 200
km near periapsis and 1000 km at high latitudes.
5. Since Venus rotates only 20 km from one orbital pass to
the next, it is not necessary to collect gravity data on
every orbit. The current mission requirement is to obtain
gravity data from at least every fourth orbit.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Quiet people aren't the
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | only ones who don't say
|_____|/ |_|/ |_____|/ | much.
Article: 2040
Newsgroups: sci.space.news
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Subject: Magellan Atlas Program
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Date: Thu, 24 Sep 1992 22:58:53 GMT
==========================
MAGELLAN ATLAS PROGRAM
September 24, 1992
==========================
An updated version of the Magellan Atlas program has been released by the
Magellan project. This program was designed to be used with the Magellan
CDROMs. This program will do the following:
o find the latitude/longitude of named features on Venus
o given a latitude/longitude, find the mosaics which lie atop
that point and the Magellan CDROMs on which they are found.
o the atlas now includes CDROMs up through 69
o the named feature descriptions includes a short description
of the meaning (origin) of the name, and adds the diameter and
crater type information listing in Schaber's "JGR - Planets"
article of August 25, 1992. Diameters for some coronae are also
listed.
o find all the named features (numbering 824) which lie in (or on) a
specific mosaic has been added, in order to help those who wish to
work with a specific CD-ROM or mosaic. (This should be helpful
to teachers, who may have only a limited set of CD-ROMs.)
There is both an IBM PC and Macintosh version of the Magellan Atlas
program. The programs are available using anonymous ftp at:
ftp: ames.arc.nasa.gov (128.102.18.3)
user: anonymous
cd: pub/SPACE/SOFTWARE
files: magellan.zip (IBM PC version -> PKZIP)
magellan.sit (Macintosh version -> STUFFIT, MacBinary format)
magellan-sit.hqx (Macintosh version -> BINEX -> STUFFIT)
Also, the database files used by the Magellan Atlas program are available.
A description of each field is included at the beginning of each file.
The underlying databases include the center latitude/longitude given in
Schaber's article also, but they are not displayed by the atlas program to
avoid confusion. The database files are available at:
ftp: ames.arc.nasa.gov (128.102.18.3)
user: anonymous
cd: pub/SPACE/MAGELLAN
files: names.txt (ASCII)
midr.txt (ASCII)
mgn-dbf.zip (2 DBase files -> PKZIP)
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Quiet people aren't the
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | only ones who don't say
|_____|/ |_|/ |_____|/ | much.
|
| 456.509 | MAGELLAN papers in JGR-Planets | VERGA::KLAES | All the Universe, or nothing! | Thu Sep 24 1992 17:57 | 646 |
| Article: 1944
Newsgroups: sci.space.news
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Subject: JGR-Planets Magellan Articles
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Date: Tue, 15 Sep 1992 05:09:20 GMT
JGR-Planets Special Magellan Issues
August 25 and October 25, 1992
This is a list of the Magellan articles published in the two special
issues of "JGR-Planets" this fall and shows the mailing address of the
senior authors, as well as the issue in which each paper will be printed.
"JGR-Planets" is available to members of AGU for $42 for the entire
year or $20 for single issues. Reprints of single papers for research
or teaching purposes are $3.50 for the first, and $1 for additional copies.
AGU can be contacted at:
American Geophysical Union
2000 Florida Avenue, N. W.
Washington, DC 20009
(202) 462-6900
Facsimile: (202) 328-0566
*****
Mg01: August, 1992
"Joints in Venusian Lava Flows"
C. Johnson, D. Sandwell
David Sandwell or Catherine Johnson
Geological Research Division
Scripps Inst. of Oceanography
La Jolla, CA 92093-0220
*****
Mg02: August, 1992
"Aeolian Features on Venus: Preliminary Magellan Results"
R. Greeley, Arvidson, Elachi, Geringer, Plaut, Saunders,
Schubert, Stofan, Thouvenot, Wall, Weitz
Ronald Greeley
Arizona State Univ.
Dept. of Geology
Tempe, AZ 85287-1404
*****
Mg03: August, 1992
"Reflection and Emission Properties in Alpha Regio"
K. Tryka, D. Muhleman
Duane Muhleman
M/S 17025
California Institute of Technology
Pasadena, CA 91125
*****
Mg04: August, 1992
"An Unusual Volcano on Venus"
H.J. Moore, Plaut, Schenk, Head
Henry Moore
354 Middlefield Road,
M/S 975
U. S. Geological Survey
Menlo Park, CA 94025
*****
Mg05: October, 1992
"Pancakelike Domes on Venus"
D. McKenzie, Ford, Liu, Pettengill
Dan McKenzie
Institute of Theoretical Geophysics
Bullard Laboratories
Madingley Road
Cambridge CB3 0EZ, U.K.
*****
Mg06: August, 1992
"Features on Venus Generated by Plate Boundary Processes"
D. McKenzie, Ford, Johnson, Parsons, Sandwell, Saunders, Solomon
Dan McKenzie
Institute of Theoretical Geophysics
Bullard Laboratories
Madingley Road
Cambridge CB3 0EZ, U.K.
*****
Mg07: August, 1992
"The Morphology and Evolution of Coronae on Venus"
Squyres, Janes, Baer, Bindschadler, Schubert, Sharpton, Stofan
Steven Squyres
326 Space Sciences Bldg.
Cornell University
Ithaca, NY 14853-6801
*****
Mg08: August, 1992
"Plains Tectonism on Venus: The Deformation Belts of Lavinia Planitia"
Squyres, Jankowski, Simons, Solomon, Hager, McGill
Steven Squyres
326 Space Sciences Bldg.
Cornell University
Ithaca, NY 14853-6801
*****
Mg09: August, 1992
"Fluid Outflows from Venus Impact Craters: Analysis from Magellan Data"
Asimow, Wood
John Wood
60 Garden Street
Smithsonian Astrophysical Observatory.
Cambridge, MA 02139
*****
Mg10: August, 1992
"Critical Taper Wedge Mechanics of Fold and Thrust Belts on Venus:
Initial Results from Magellan"
Suppe, Connors
John Suppe
Department of Geological and Geophysical Science
Princeton University
Princeton, NJ 085441003
*****
Mg11: August, 1992
"The Geology and Distribution of Impact Craters on Venus:
What Are They Telling Us?"
Schaber, Strom, Moore, Soderblom, Kirk, Chadwick, Dawson, Gaddis,
Boyce, Russell
Gerald Schaber
US Geological Survey
Geologic Division
2255 North Gemini Drive
Flagstaff, AZ 86001
*****
Mg12: August, 1992
"Images and Topographic Relief at the North Pole of Venus"
Leberl, Maurice, Thomas, Leff, Wall
Franz W. Leberl
Vexcel Corp.
2477 55th St.
Boulder, CO 80301
*****
Mg13: August, 1992
"Magellan Observations of Alpha Regio: Implications for Formation
of Complex Ridged Terrains on Venus"
Bindschadler, deCharon, Head, Beratan, Smrekar
Duane Bindschadler
Dept. Earth and Space Sciences
University of California
Los Angeles, CA 90024-1567
*****
Mg14: October, 1992
"Small Volcanic Edifices and Volcanism in the Plains of Venus"
Guest, Bulmer, Aubele, Beratan, Greeley, Head, Michaels, Weitz,
Wiles
John Guest
Mill Hill Park
University of London Observatory
University College London
London, England NW72QS U.K.
*****
Mg15: October, 1992
"Mineral Equilibria and The High Radar Reflectivity of Venus
Mountaintops"
Klose, Wood, Hashimoto
John Wood
60 Garden Street
Smithsonian Astrophysical Observatory.
Cambridge, MA 02139
*****
Mg16: October, 1992
"Analysis of Volcanic Surface Morphology on Venus from Comparison
of Arecibo, Magellan, and Terrestrial Airborne Radar Data"
B. Campbell & D. Campbell
Donald Campbell
Space Sciences Building
Department of Astronomy
Cornell University
Ithaca, NY 14853
*****
Mg17: August, 1992
"The Rotation Period, Direction of the North Pole, and Geodetic
Control Network of Venus"
Davies, Colvin, Rogers, Chodas, Sjogren, Akim, Stepanyantz,
Vlasova, and Zakharov
Merton Davies
1700 Main Street
The RAND Corporation
Santa Monica, CA 90406
*****
Mg18: October, 1992
"Styles of Deformation in Ishtar Terra and Their Implications"
Kaula, Bindschadler, Grimm, Hansen, Roberts, Smrekar
William M. Kaula
Dept. Earth and Space Sciences
University of California
Los Angeles, CA 90024-1567
*****
Mg19: October, 1992
"Flexural Ridges, Trenches and Outer Rises Around Venus Coronae"
Sandwell, Schubert
David Sandwell
Geological Research Division
A020
Scripps Inst. of Oceanography
La Jolla, CA 92093
*****
Mg20: October, 1992
"Mylitta Fluctus, Venus: Rift Related, Centralized Volcanism and
the Emplacement of Large Volume Flow Units"
Magee Roberts, Guest, Head, Lancaster
Kari Magee Roberts
Dept. Geological Sciences
Box 1846
Brown University
Providence, RI 02912
*****
Mg21: August, 1992
"Channels and Valleys on Venus: Preliminary Analysis of Magellan Data"
Baker, Komatsu, Parker, Gulick, Kargel, Lewis
Vic Baker
Dept. Of Geosciences
Building #77
University of Arizona
Tucson, AZ 85721
*****
Mg22: October, 1992
"Magellan Observations of Extended Impact Crater Related Features
on the Surface of Venus"
Campbell, Stacy, Newman, Arvidson, Jones, Musser, Roper, Schaller
Donald Campbell
Space Sciences Building
Department of Astronomy
Cornell University
Ithaca, NY 14853
*****
Mg23: August, 1992
"Global Distribution and Characteristics of Coronae and Related
Features on Venus: Implications for Origin and Relation to Mantle
Processes"
Stofan, Sharpton, Schubert, Baer, Bindschadler, Janes, Squyres
Ellen Stofan
JPL, MS 230-225
4800 Oak Grove Dr.
Pasadena, CA 91109
*****
Mg24: August, 1992
"Scattering Properties of Venus' Surface: Preliminary Results from Magellan"
Tyler, Simpson, Maurer, Holmann
G. Leonard Tyler
Center for Radar Astronomy
Stanford University
Stanford, CA 94305-4055
*****
Mg25: August, 1992
"Fractal Analysis of Venus Topography in Tinatin Planitia and Ovda Regio"
Kucinskas, Turcotte, Huang, Ford
Algis B. Kucinskas or Donald Turcotte
2122 Snee Hall
Department of Geological Sciences
Cornell University
Ithaca, NY 14853
*****
MG26: August, 1992
"Coldspots and Hotspots: Global Tectonics and Mantle Dynamics of Venus"
Bindschadler, Schubert, Kaula
Duane Bindschadler
Dept. Earth and Space Sciences
University of California
Los Angeles, CA 90024-1567
*****
Mg27: October, 1992
"Dyke Emplacement on Venus and on the Earth"
McKenzie, McKenzie, Saunders
Dan McKenzie
Institute of Theoretical Geophysics
Bullard Laboratories
Madingley Road
Cambridge CB3 0EZ, U.K.
*****
Mg28: October, 1992
"Comparison of Goldstone and Magellan Radar Data in the
Equatorial Plains of Venus"
Plaut, Arvidson
Jeff Plaut
JPL, MS 230-225
4800 Oak Grove Dr.
Pasadena, CA 91109
*****
Mg29: October, 1992
"Gravitational Spreading of High Terrain in Ishtar Terra, Venus"
Smrekar, Solomon
Sue Smrekar
MIT
Dept. Earth Atmospheric and Planetary Sci.
Building 54, Room 522
Cambridge, MA 02139
*****
Mg30: August, 1992
"Surface Modification of Venus As Inferred From Magellan
Observations of Plains and Tesserae"
Arvidson, Greeley, Malin, Saunders, Izenberg, Plaut, Stofan
Ray Arvidson
Dept. Earth and Planetary Sciences
Campus Box 1169
Washington University
St. Louis, MO 63130-4899
*****
Mg31: (Later issue)
"Cleopatra Crater on Venus: A Happy End to the Impact-Volcanic
Controversy"
Kirk, Schaber, Ivanov, Potapov, Basilevsky
Alexandr Basilevsky
Kosygin Street 19
Academy of Sciences
Vernadsky Institute of Geochemistry
Moscow, 11975 USSR
or
Gerald Schaber
US Geological Survey
Geologic Division
2255 North Gemini Drive
Flagstaff, AZ 86001
*****
Mg32: October, 1992
"Mass Movements on Venus: Preliminary Results from Magellan Cycle I
Observations"
Malin
Michael Malin
Malin Space Science Systems
3535 General Atomics Court
Suite 250
San Diego, CA 92121
*****
Mg33: August, 1992
"Venus: Topography and Kilometer Scale Slopes"
Ford, Pettengill
Peter Ford
Building 37, Room 601
Dept. of Space Sciences
MIT
Cambridge, MA 02139
*****
Mg34: August, 1992
"Steepsided Domes on Venus: Characteristics, Geologic Setting,
and Eruption Conditions from Magellan Data"
Pavri, Head, Klose, Wilson
Betina Pavri
Dept. Geological Sciences
Box 1846
Brown University
Providence, RI 02912
*****
Mg35: August, 1992
"Regional Topographic Rises on Venus: Geology of Western Eistla
Regio and Comparison to Beta Regio and Atla Regio"
Senske, Schaber, Stofan
Dave Senske
Dept. Geological Sciences
Box 1846
Brown University
Providence, RI 02912
*****
Mg36: (Probably a later issue)
"Atmospheric Effects on Cratering on Venus"
Takata, Ahrens, Hornung, Phillips
Toshiko Takata
M/S 25221
California Institute of Technology
Pasadena, CA 91125
*****
Mg37: October, 1992
"Geological Correlations with the Interior Density Structure of
Venus"
Herrick, Phillips
Robert Herrick
Department of Geological Sciences
Southern Methodist University
Dallas, TX 75275
or
Roger Phillips
Dept. Earth and Planetary Sciences
Campus Box 1169
Washington University
St. Louis, MO 63130-4899
*****
Mg38: October, 1992
"Impact Crater Distribution on Venus: Implications for Planetary
Resurfacing History"
Phillips, Raubertas, Arvidson, Sarkar, Herrick, Izenberg, Grimm,
Roger Phillips
Dept. Earth and Planetary Sciences
Campus Box 1169
Washington University
St. Louis, MO 63130-4899
*****
Mg39: October, 1992
"Anatomy of a Venusian Hotspot: Geology, Gravity, and Mantle
Dynamics of Eistla Regio"
Grimm, Phillips
Robert Grimm
Dept. Geology
ASU
Tempe, AZ 85287-1404
*****
Mg40: October, 1992
"Impact Cratering on Venus: Physical and Mechanical Models"
Ivanov, Nemchinov, Svetsov, Provalov, Khazins, Phillips
B. A. Ivanov
Kosygin street, 19
Schmidt Institute of Earth Physics
Moscow, 123810 USSR
*****
Mg41: October, 1992
"Atmospheric Effects on Ejecta Emplacement and Crater Formation
on Venus from Magellan"
Schultz
Peter Schultz
Dept. Geological Sciences
Box 1846
Brown University
Providence, RI 02912
*****
Mg42: August, 1992
"Venus Tectonics: An Overview of Magellan Observations"
Solomon, Smrekar, Bindschandler, Saunders, Schubert, Squyres,
Stofan
Sean Solomon
MIT
Dept. Earth Atmospheric and Planetary Sci.
Building 54, Room 522
Cambridge, MA 02139
Mg43:L August, 1992
"Magellan: Mission Summary"
Saunders, et al.
R. Stephen Saunders
JPL, MS 230-225
4800 Oak Grove Dr.
Pasadena, CA 91109
*****
Mg44: October, 1992
"Geophysical Models for the Formation and Evolution of Corona on
Venus"
Janes, Bindschadler, Baer, Schubert, Sharpton, Squyres, Stofan
Daniel Janes
420 Space Sciences Bldg.
Cornell University
Ithaca, NY 14853-6801
*****
Mg45: October, 1992
"Small Scale Fracture Patterns on the Volcanic Plains of Venus"
Banerdt & Sammis
Bruce Banerdt
4800 Oak Grove Drive
Jet Propulsion Laboratory
Mail Stop 183-501
Pasadena, CA 91108
*****
Mg46: August, 1992
"Initial Results from the Magellan Stereo Experiment"
Leberl, Thomas, Maurice
Franz W. Leberl
Vexcel Corp.
2477 55th St.
Boulder, CO 80301
*****
Mg47: October, 1992
"Geology of the Venera 8 Landing Site Region from Magellan Data:
Morphological and Geochemical Considerations"
Basilevsky, Nikolayeva, Weitz
Alexandr Basilevsky
Kosygin Street, 19
Academy of Sciences
Vernadsky Institute of Geochemistry
Moscow, 11975 USSR
*****
Mg48: August, 1992
"Venus Volcanism: Classification of Volcanic Features and
Structures, Associations, and Global Distribution from Magellan Data"
Head, Crumpler, Aubele, Guest, Saunders
James W. Head
Dept. Geological Sciences
Box 1846
Brown University
Providence, RI 02912
*****
Mg49: August, 1992
"Venus Surface Radiothermal Emission"
Pettengill, Ford, Wilt
Gordon Pettengill
Center for Space Research
Building 37, Room 641
MIT
Cambridge, MA 02139
*****
October, 1992
"Enhanced Visualization for Interpretation of Magellan Radar
Data: Supplement to Magellan Special Issue"
Randy Kirk
US Geological Survey
Geologic Division
2255 North Gemini Drive
Flagstaff, AZ 86001
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Anything is impossible if
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | you don't attempt it.
|_____|/ |_|/ |_____|/ |
|
| 456.510 | How MAGELLAN radar-maps Venus | VERGA::KLAES | All the Universe, or nothing! | Fri Oct 02 1992 17:17 | 52 |
| Article: 49597
Newsgroups: sci.space
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Subject: Re: Magellan
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Date: Fri, 2 Oct 1992 15:17:41 GMT
In article <1992Oct1.224613.29180@unocal.com>, stgprao@st.unocal.COM
(Richard Ottolini) writes...
>How does Magellan move its radar attena to transmit results to earth?
>Is it an electric motor powered by solar power or thrusters?
>Is this the ultimate limitation on Magellan's lifetime then, barring
>breakdowns?
The entire spacecraft is turned towards Earth twice on each orbit to
transmit the radar mapping data back to Earth. The turns are done by
using three spinning reactions wheels (one for each axis of rotation).
The wheels are spun at different speeds to turn the spacecraft using
the transfer of momentum principle, and this is all done without using
any propellant. The reaction wheels do pick up excessive speed from
the solar wind and the gravity of Venus, so this excessive speed is
bled off by firing the thrusters briefly twice a day (referred to as
desats in the Magellan status reports).
Magellan has been a busy little beaver in sending back its data to
Earth. On a typical mapping orbit, the antenna is pointed towards
Venus and bounces the radar off the planet and records it onto the
tape recorders. It then turns towards Earth using the reaction wheels
and transmits half the data back to Earth for about an hour. Magellan
then turns away from Earth to lock on two reference stars with its
star scanner to see if its attitude position has drifted any, and if
so, then makes a minor attitude adjustment with the reaction wheels.
This is called a star calibration. It then turns back to Earth and
sends the remaining data from the tape recorder. The spacecraft has
now completed one orbit and turns back to Venus to start the next
mapping pass.
This pirouette around the planet is repeated every 3.26 hours, and is
done day in and day out, 24 hours a day, for most of the 2+ years that
Magellan has been orbiting Venus. It is an amazing engineering feat
that has mostly gone unnoticed, and a lot of credit goes to the
spacecraft designers who made it work so well.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Einstein's brain is stored
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | in a mason jar in a lab
|_____|/ |_|/ |_____|/ | in Wichita, Kansas.
|
| 456.511 | Updates - September 24 to October 1 | VERGA::KLAES | All the Universe, or nothing! | Fri Oct 02 1992 19:58 | 257 |
| Article: 2043
Newsgroups: sci.space.news
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Subject: Magellan Update - 09/24/92
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Date: Fri, 25 Sep 1992 02:42:02 GMT
Forwarded from the Magellan Project
MAGELLAN STATUS REPORT
September 24, 1992
1. Magellan continues to operate normally, performing the
battery reconditioning sequence which was completed on
schedule last night.
2. Yesterday controllers uplinked commands to perform a
memory readout of the triple TWTA (Traveling Wave
Tube Amplifier) SSO (Spurious Shutoff) which occured late
Sunday. The results of the readout are still being analyzed.
3. Tomorrow the G2269 command sequence will be uplinked to the spacecraft.
4. The primary science data being gathered during Magellan's
Cycle 4 is gravimetric measurements, i.e. fluctuations in
the orbit caused by variations in the local density of
Venus. These measurements have a resolution of about 200
km near periapsis and 1000 km at high latitudes.
5. Since Venus rotates only 20 km from one orbital pass to
the next, it is not necessary to collect gravity data on
every orbit. The current mission requirement is to obtain
gravity data from at least every fourth orbit.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Quiet people aren't the
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | only ones who don't say
|_____|/ |_|/ |_____|/ | much.
Article: 2058
Newsgroups: sci.space.news
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Subject: Magellan Update - 09/25/92
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Date: Sat, 26 Sep 1992 09:36:32 GMT
Forwarded from the Magellan Project
MAGELLAN STATUS REPORT
September 25, 1992
1. Magellan continues to operate normally, performing gravity
data collection in its fourth cycle of Venus.
2. Yesterday controllers uplinked the G2269 command sequence
which began execution at 9:42 AM PDT.
3. Magellan has now completed the battery reconditioning
sequence and is 86 orbits into the 1790 orbit cycle of
gathering gravimetric measurements, i.e. fluctuations in
the orbit caused by variations in the local density of Venus.
4. These measurements will enable scientists to map the
variations in the density of Venus and correlate these
variations with surface features. This will reveal the
internal structure of the planet and help scientists to
confirm the processes which produced the extensive
highlands and volcanic features.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Quiet people aren't the
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | only ones who don't say
|_____|/ |_|/ |_____|/ | much.
Article: 2066
Newsgroups: sci.space.news
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Subject: Magellan Update - 09/28/92
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Date: Tue, 29 Sep 1992 08:03:58 GMT
Forwarded from the Magellan Project
MAGELLAN STATUS REPORT
September 28, 1992
1. Magellan continues to operate normally, performing a
starcal (star calibration) and desat (desaturation of
the reaction wheels) on every orbit, and transmitting a
carrier signal which is precisely tracked by the DSN
(Deep Space Network) stations to provide gravity data to
scientists.
2. Since Friday, when the spacecraft began execution of G2269
command sequence, only one star has been missed during the
starcals. The new sequence included a new star pair for
the calibration maneuvers.
3. On Saturday the DSN station had difficulty locking up to
the 1200 bps X-band downlink signal. It was determined
that the low AGC (Automatic Gain Control) was a result of
the transmitter temperature being down to 53.3 degrees C.
Controllers raised the radar system heater set points to
25-27 degrees and the tracking has been normal since.
The transmitter presently varies between 54 and 55 degrees C.
4. Magellan has completed 5744 orbits of Venus, 107 in Cycle 4.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Quiet people aren't the
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | only ones who don't say
|_____|/ |_|/ |_____|/ | much.
Article: 2082
Newsgroups: sci.space.news
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Subject: Magellan Update - 09/29/92
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Date: Thu, 1 Oct 1992 00:24:09 GMT
Forwarded from the Magellan Project
MAGELLAN STATUS REPORT
September 29, 1992
1. Magellan continues to operate normally, performing a
starcal (star calibration) and desat (desaturation of
the reaction wheels) on every orbit, and transmitting a
carrier signal which is precisely tracked by the DSN
(Deep Space Network) stations to provide gravity data to
scientists.
2. The transmitter is presently peaking at 55 degrees C,
which seems to be the right temperature for maintaining
the x-band communications.
3. Today at noon, Julie Webster from MMC (Martin Marietta)
presented a talk on "Operating the Magellan Telecommunications
Subsystem" in von Karman auditorium. This was part of the SSORCE
series to share the lessons learned from JPL flight projects.
4. The Magellan Lunchtime Seminar featuring Dr. Tommy
Thompson, speaking on "Radar Studies of the Moon," has
been rescheduled to this Friday, Oct. 2.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Quiet people aren't the
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | only ones who don't say
|_____|/ |_|/ |_____|/ | much.
Article: 2087
Newsgroups: sci.space.news
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Subject: Magellan Update - 09/30/92
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Date: Thu, 1 Oct 1992 04:57:25 GMT
Forwarded from the Magellan Project
MAGELLAN STATUS REPORT
September 30, 1992
1. Magellan continues to operate normally, performing a
starcal (star calibration) and desat (desaturation of
the reaction wheels) on every orbit. All starcals during
the past two days have been successful.
2. The transmitter continues to peak at 55 degrees C, with a
thermal cycle of 1.4 deg.
3. Magellan is transmitting an X-band carrier signal which is
precisely tracked by the DSN (Deep Space Network) stations
to provide gravity data to scientists.
4. The current elliptical orbit resolution diminishes
significantly above 40 degrees of latitude. Global
gravity mapping at the 200 km resolution would require a
circular orbit.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Quiet people aren't the
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | only ones who don't say
|_____|/ |_|/ |_____|/ | much.
Article: 26968
Newsgroups: sci.space,sci.astro,alt.sci.planetary
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Subject: Magellan Update - 10/01/92
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Date: Fri, 2 Oct 1992 03:18:47 GMT
Forwarded from the Magellan Project
MAGELLAN STATUS REPORT
October 1, 1992
1. Magellan continues to operate normally, performing a
starcal (star calibration) and desat (desaturation of
the reaction wheels) on every orbit.
2. The transmitter continues to peak at 55 degrees C, with a
thermal cycle of 1.4 deg.
3. The present mission cycle offers the unique opportunity to
observe the periapsis of Magellan's orbit for 243 days,
one full rotation of Venus. Since the gravitational
effects on the orbit are governed by the "Inverse Square
Law," that the force of gravity is proportional the the
masses (of Venus and the spacecraft) and inversely
proportional to the square of the distance between them,
the low portion of the orbits is the best for measuring
the gravity variations.
4. Magellan came out of the last period of periapsis
occultations at the end of Cycle 3. This also provided a
unique opportunity for atmospheric scientists because,
just as the low part of the orbit became "visible" to the
DSN (Deep Space Network) tracking stations, the radio signal
was passing through the atmosphere of Venus. Fluctuations
in the signal provided a measure of density variations in the
atmosphere.
5. These measurements will complement data from the Pioneer-
Venus Orbiter, which is dipping into the upper atmosphere
of Venus on a "death spiral" which is expected to end in
December.
6. Tomorrow, October 2nd, Tommy Thompson will present a
"Brown Bag" Seminar on "Radar Studies of the Moon,"
describing earth-based radar observations of the world's
natural satellite. This presentation was postponed from
Sept. 25 due to the press conference which followed the
Mars Observer launch.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Quiet people aren't the
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | only ones who don't say
|_____|/ |_|/ |_____|/ | much.
|
| 456.512 | Updates - October 2-12 | VERGA::KLAES | All the Universe, or nothing! | Tue Oct 13 1992 22:14 | 207 |
| Article: 2110
Newsgroups: sci.space.news
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Subject: Magellan Update - 10/02/92
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Date: Sat, 3 Oct 1992 15:45:53 GMT
Forwarded from the Magellan Project
MAGELLAN STATUS REPORT
October 2, 1992
1. Magellan continues to operate normally, performing a
starcal (star calibration) and desat (desaturation
of the reaction wheels) on every orbit and transmitting
a good signal to the DSN (Deep Space Network) stations
for gravity data collection.
2. The transmitter continues to peak at 55 degrees C, with a
thermal cycle of 1.4 deg.
3. The present mode of operation will continue through the
end of Cycle 4 on May 15, 1993.
4. Software Interface Specifications (SIS) have been made for
all digitized synthetic aperture radar (SAR) and altimetry
data products. SISs are detailed instructions for users
of digitized data products including optical disks and CDs.
5. As part of the special visitor activities surrounding the
Mars Observer launch, Dr. R. Stephen Saunders, the
Magellan Project Scientist; Craig Leff, the Magellan
Science Data Coordinator; and Dave Doody, the Mission
Control Team Deputy Team Chief gave presentations about
the Magellan mission and its findings.
6. Tommy Thompson presented a "Brown Bag" Seminar on "Radar
Studies of the Moon," describing Earth-based radar
observations and how they related to Venus radar studies.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Einstein's brain is stored
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | in a mason jar in a lab
|_____|/ |_|/ |_____|/ | in Wichita, Kansas.
Article: 2116
Newsgroups: sci.space.news
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Subject: Magellan Update - 10/05/92
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Date: Tue, 6 Oct 1992 05:18:49 GMT
Forwarded from the Magellan Project.
MAGELLAN STATUS REPORT
October 5, 1992
1. The Magellan spacecraft, now in its fourth 243-day cycle
at Venus, continues to operate normally. The principal
activity is two-way X-band communication with Earth which
provides precise doppler measurements of the signal when
Magellan is in the low part of its orbit (periapsis).
This activity will continue until May 15, 1993.
2. By studying the variations in the doppler shift, gravity
scientists can plot the variations in the density of Venus
and map the variations in relation to surface topography.
This provides another dimension to the radar, altimetry,
and emissivity data which has been gathered to date.
3. The transmitter continues to peak at 55.5 degrees C, with
a thermal cycle of 1.4 deg.
4. Here on Earth, the principal Magellan activity has been to
get the science products into the hands of the science
community and investigators. Ninety-five more mosaiced
images were released October 1. Fourteen new compact
disks of mosaics were approved for distribution to the
general science community during October, bringing to 66
the total available. The next ten CDs are scheduled for
distribution in early 1993.
5. Production has started on five new CD's containing the
Altimetry-Radiometry data, bring this total to fifteen
when released to the community in early 1993.
6. To date, 347 of the 378 orbits corrupted by the
deterioration of DMS-A (one of the spacecraft tape
recorders) during Cycle 1 have been processed into usable
Experiment Data Records (EDRs) through special processing
on the Magellan High Rate computer. About 200 of these
EDRs have been further processed into Full-resolution
Basic Image Data Records (F-BIDRs) by the SAR (Synthetic
Aperture Radar) Data Processing Team.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Einstein's brain is stored
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | in a mason jar in a lab
|_____|/ |_|/ |_____|/ | in Wichita, Kansas.
Article: 2135
Newsgroups: sci.space.news
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Subject: Magellan Update - 10/06/92
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Date: Wed, 7 Oct 1992 07:41:21 GMT
Forwarded from the Magellan Project
MAGELLAN STATUS REPORT
October 6, 1992
1. The Magellan spacecraft, now in its fourth 243-day cycle
at Venus, continues to operate normally. All starcals
(star calibrations) yesterday were successful and the
transmitter continues to peak at 55.4 degrees C.
2. Yesterday controllers sent express commandss to perform a
memory readout of the on-board fault protection records.
This verified that a double TWTA (Traveling Wave Tube
Amplifier) SSO (Spurious Shutoff) had occurred on Sunday.
3. Throughout the mission-to-date, Magellan has had 25 SSOs
on TWTA-A and 39 on TWTA-B. With the current fault
protection configuration, the spacecraft immediately
returns to normal operations, with no commanding from the ground.
4. The following is a statistical summary of the mission to date:
DAYS
TOTAL DAYS . . . . . . . . . . . . . . . . .. . . . 791 DAYS
DAYS OF SCIENCE DATA ACQUISITION . . . . . . 596
ORBITS
TOTAL ORBITS . . . . . . . . . . . . . . . . . . . .5550 ORBITS
MAPPING ORBITS . . . . . . . . . . . . . . 4828
GRAVITY DATA ONLY ORBITS . . . . . . . . . .192
PERCENTAGE OF VENUS SURFACE AREA IMAGED
TOTAL CYCLE 1 COVERAGE: 83.7%
TOTAL CYCLE 2 COVERAGE: 54.5%
TOTAL CYCLE 3 (STEREO) 22.8%
TOTAL CYCLE 4 (GRAVITY) 9.3% **
MISCELLANEOUS RECOVERED GAPS +14.6%
PERCENTAGE OF VENUS SURFACE IN CAPTURED DATA . 99.0%
** Percent of the total planned orbits in Cycle 4. Gravity
data requirement is for one in every four orbits.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Einstein's brain is stored
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | in a mason jar in a lab
|_____|/ |_|/ |_____|/ | in Wichita, Kansas.
Article: 2182
Newsgroups: sci.space.news
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Subject: Magellan Update - 10/12/92
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Date: Tue, 13 Oct 1992 07:24:58 GMT
Forwarded from the Magellan Project
MAGELLAN STATUS REPORT
October 12, 1992
1. The Magellan spacecraft continues to operate normally.
2. The G2283 command sequence which began execution on Friday
contains 40-minute cooling periods. This has brought the
spacecraft temperatures down to the range planned for this
phase of Cycle 4.
3. However, with Transmitter B ranging between 50.4 and 52.5
degrees C, the DSN (Deep Space Network) stations have been
unable to lockup on the 1200 bps engineering telemetry. So
an express command was uplinked to switch to 40 bps, and that
is the present status.
4. Spacecraft controllers are planning to change the radar
heater set points to bring the transmitter back up to its
preferred operating temperature near 55 degrees C.
5. The Magellan Project office managers concluded a
successful planning retreat on Friday. The project's
principle goals and activities through the End-of Project
will be communicated to Flight Team members soon.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Einstein's brain is stored
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | in a mason jar in a lab
|_____|/ |_|/ |_____|/ | in Wichita, Kansas.
|
| 456.513 | Updates - October 14-26 | VERGA::KLAES | All the Universe, or nothing! | Tue Nov 03 1992 17:24 | 234 |
| Article: 2198
Newsgroups: sci.space.news
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Subject: Magellan Update - 10/14/92
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Date: Thu, 15 Oct 1992 06:50:51 GMT
Forwarded from the Magellan Project
MAGELLAN STATUS REPORT
October 14, 1992
1. The Magellan spacecraft continues to operate normally,
performing two 40-minute cooling periods, a starcal
(star calibration) and desat (desaturation of the
reaction wheels) in each 3-hour orbit, and transmitting
a carrier signal which is precisely tracked by the DSN
(Deep Space Network) stations to extract gravity data.
2. Due to the temperature drop which resulted from the longer
cooling periods, the X-band telemetry signal was degraded.
The DSN stations were unable to lock up to the 1200 bps
engineering, so a switch to 40 bps telemetry was made.
3. Today, October 14, the Project provided responses on the
history, management, and development phases of
VOIR/VRM/Magellan to a Project Planning Panel appointed by
the NASA Administrator.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Einstein's brain is stored
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | in a mason jar in a lab
|_____|/ |_|/ |_____|/ | in Wichita, Kansas.
Article: 2219
Newsgroups: sci.space.news
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Subject: Magellan Update - 10/19/92
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Date: Tue, 20 Oct 1992 07:04:59 GMT
Forwarded from the Magellan Project
MAGELLAN STATUS REPORT
October 19, 1992
1. The Magellan spacecraft continues to operate normally,
performing two 40-minute cooling periods, a starcal
(star calibration) and desat (desaturation of the
reaction wheels) in each 3-hour orbit, and transmitting
a carrier signal which is precisely tracked by the DSN
(Deep Space Network) stations to extract gravity data.
2. All of the starcals over the weekend were successful
except two, which were partially successful. This means
the star tracker failed to detect one of the two stars during
the scan, but the attitude control remains very precise.
3. The spacecraft continues to send engineering telemetry at
40 bps. Due to thermal cycling of transmitter B the DSN
stations are unable to lock up to the 1200 bps signal.
4. Magellan is now passing through the shadow of Venus during
the apoapsis portion of each orbit. Since it travels
slower while more distant from Venus, it spends nearly an
hour of each orbit in the shadow.
5. At last Friday's ceremony in Washington, D.C., at which
the Magellan Team received the Smithsonian Air & Space
award for current achievement, the IMAX film, "Magellan at
Venus," again had a sensational impact on the attendees,
including NASA Administrator Dan Goldin, JPL Director Ed
Stone, Assistant Lab Director for Flight Projects John
Casani and several hundred other invited dignitaries.
Note: Effective with this report, the Magellan Status will be
issued only on Mondays and Fridays.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | If God had wanted us to
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | have elections, he would
|_____|/ |_|/ |_____|/ | have given us candidates.
Article: 2224
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space.news
Subject: Mars & Magellan Images
Date: 20 Oct 92 12:42:42 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
==========================
MARS & MAGELLAN IMAGES
October 19, 1992
==========================
Two Mars images and line drawings of the Magellan spacecraft are now
available at the anonymous ftp site at ames.arc.nasa.gov. The Mars images
are in both GIF and JPEG format, and show two views of the Mars globe as
constructed by USGS from the Viking Orbiter images.
ftp: ames.arc.nasa.gov (128.102.18.3)
user: anonymous
cd: pub/SPACE/GIF
files: mars1.gif
mars2.gif
cd: pub/SPACE/JPEG
files: mars1.jpg
mars2.jpg
The "Magellan" drawing is quite accurate. The "VGRAM" drawing has
been used frequently in Magellan publications, but actually represents
an early spacecraft design. In the flight hardware, the attachment of
the propulsion thrusters was to a separate "propulsion equipment module",
rather than to the bus itself, as VGRAM shows. The Magellan images are
available in GIF format and as Macintosh StartupScreen files.
cd: pub/SPACE/GIF
files: magellan.gif
vgram.gif
cd: pub/SPACE/MAGELLAN/CAPTIONS
files: magellan.bin (Macintosh StartupScreen files, MacBinary)
magellan.hqx (Macintosh StartupScreen files -> BinHex)
vgram.bin (Macintosh StartupScreen files, MacBinary)
vgram.hqx (Macintosh StartupScreen files -> BinHex)
#######
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | If God had wanted us to
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | have elections, he would
|_____|/ |_|/ |_____|/ | have given us candidates.
Article: 2265
Newsgroups: sci.space.news
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Subject: Magellan Update - 10/23/92
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Date: Sat, 24 Oct 1992 02:38:30 GMT
Forwarded from the Magellan Project
MAGELLAN STATUS REPORT
October 23, 1992
1. Magellan continues to operate normally, performing a
starcal (star calibration) and desat (desaturation of
the reaction wheels) on each orbit and transmitting a
carrier plus 40 bps X-band signal.
2. The craft has completed 5930 orbits of Venus. 295 orbits
have been completed in Cycle 4. Since the science
requirement is to collect gravity data on at least one
out of every four orbits, we have about 75 orbits of
gravity. This represents about 17.6% of the coverage we
expect to get during Cycle 4 (or 63 degrees of longitude
out of the 360 degrees).
3. The G2297 command sequence was uplinked to the spacecraft
late yesterday. In addition to the normal operations,
this sequence includes a calibration of the Attitude
Reference Unit and scale factor check of the gyros to be
performed this weekend.
4. Magellan is now passing through the shadow of Venus
during the apoapsis portion of each orbit. Since it
travels slower while more distant from Venus, it spends
nearly an hour of each orbit in the shadow.
5. Dr. Steve Saunders, Jerry Clark, Phil Allin, Greg
Michaels, Mona Jasnow, and Neil Nickle are among the
Magellan team members attending the 1992 Geological
Society of America Convention in Cincinnati from October
25 through 28. The theme of the meeting is "From
Columbus to Magellan," and an exhibit of the Magellan
results at Venus will be set up and staffed by the team.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | If God had wanted us to
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | have elections, he would
|_____|/ |_|/ |_____|/ | have given us candidates.
Article: 2302
Newsgroups: sci.space.news
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Subject: Magellan Update - 10/26/92
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Date: Tue, 27 Oct 1992 05:31:33 GMT
Forwarded from the Magellan Project
MAGELLAN STATUS REPORT
October 26, 1992
1. The command sequence G2297 started execution on Friday,
October 23rd with a switch to backup gyro channels. This
was necessary to perform a long awaited gyro scale factor
check and complete Attitude Reference Unit (ARU)
calibration while on backup channels.
2. Redundant scale factor checks and ARU calibrations were
successfully performed, but required ground commanded
attitude error corrections three times during the
weekend. Error corrections were required due to nature
of gyro scale factor test.
3. Magellan continues to operate normally, performing a
starcal (star calibration) and desat (desaturation of
the reaction wheels) on each orbit and transmitting a
carrier plus 40 bps x-band signal.
4. Final reconfiguration from this weekends gyro test will
take place today with the switch to primary gyro channels.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | If God had wanted us to
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | have elections, he would
|_____|/ |_|/ |_____|/ | have given us candidates.
|
| 456.514 | Updates - October 30 to November 2; CD-ROM info | VERGA::KLAES | All the Universe, or nothing! | Fri Nov 13 1992 19:25 | 252 |
| Article: 2322
Newsgroups: sci.space.news
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Subject: Magellan Update - 10/30/92
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Date: Sat, 31 Oct 1992 05:55:59 GMT
Fowarded from the Magellan Project
MAGELLAN STATUS REPORT
October 30, 1992
1. Magellan continues to operate normally, performing a
starcal (star calibration) and desat (desaturation of
the reaction wheels) on each orbit and transmitting a
carrier plus 40 bps X-band signal.
2. No commanding of the spacecraft is planned for today or
the weekend. Magellan continues to pass through the
shadow of Venus during the apoapsis portion of each orbit.
3. The craft has completed 5982 orbits of Venus, just 18
orbits from the 6000 mark. 346 orbits have been completed
in Cycle 4. Since the science requirement is to collect
gravity data on at least one out of every four orbits, we
have about 86 orbits of gravity. This represents about 70
degrees of longitude out of the 360 degree coverage planned.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | If God had wanted us to
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | have elections, he would
|_____|/ |_|/ |_____|/ | have given us candidates.
Article: 2366
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space.news
Subject: Magellan Update - 11/02/92
Date: 3 Nov 92 04:25:27 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
MAGELLAN STATUS REPORT
November 2, 1992
1. Magellan continues to operate normally, performing a
starcal (star calibration) and desat (desaturation of
the reaction wheels) on each orbit and transmitting a
carrier plus 40 bps X-band signal.
2. Presently the spacecraft performs two "hides" (periods in
the shadow of the High Gain Antenna) as well as time in
the shadow of Venus. The temperature of Bay 7 which
contains the CDS (Command Data Subsystem) peaks at
47 degrees C with a 9 to 10 degree cycle.
3. The spacecraft controllers are planning to switch the
engineering telemetry to 1200 bps and perform a memory
readout of a portion of the CDS in preparation for
uplinking some changes to the on-board fault protection.
A series of thirteen non-standard and express commands
will be send early tomorrow.
4. Magellan passed the 6000 orbit mark yesterday at 5:46 PM
PST. 368 orbits have been completed in Cycle 4, 20% of
the cycle coverage planned.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Give people a second
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | chance, but not a third.
|_____|/ |_|/ |_____|/ |
Article: 2381
Newsgroups: sci.space.news
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Subject: Magellan CD-ROMs
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Date: Fri, 6 Nov 1992 11:26:08 GMT
=====================================
MAGELLAN CD-ROMs
Cycle 2
November 5, 1992
=====================================
Fourteen more Magellan CD-ROMs (volumes 53 through 66) have now
been released by the Magellan project. A total of 77 Magellan CD-ROMs
are now available: 66 CD-ROMs containing radar images, and 11 CD-ROMs
containing altimetry data. Volumes 1 through 52 contain the radar
images taken by the Magellan spacecraft during Cycle 1, the first 8
month mapping of the planet Venus. Volumes 53 through 66 are the
first release of the Cycle 2 radar data.
The CD-ROMs can be obtained from the National Space Science Data
Center (NSSDC) at the Goddard Space Flight Center. The "nominal"
charge is $20 for the first CD-ROM, and $6 for any additional CD-ROM
in an order. However, NSSDC may waive this charge for a small amount
of data requested by bona fide research users, government
laboratories, etc. School teachers who are unable to pay may be
helped on a case by case basis, and/or as resources permit.
Researchers funded by NASA's Solar System Exploration Division can
also obtain the CD-ROMs through the Planetary Data System at JPL.
NSSDC's address is:
National Space Science Data Center
Goddard Space Flight Center
Greenbelt, Maryland 20771
Tel: (301) 286-6695
Email address: request@nssdca.gsfc.nasa.gov
You can also reach NSSDC by logging on to their computer. To log
onto the NSSDC computer, telnet to NSSDC.GSFC.NASA.GOV and give the
username "NSSDC". You will then be connected to a menu system which
allows you to use the "Master Directory". You can also leave
questions and orders for the NSSDC staff. If this is the first time
you have used the NSSDC "NODIS" system, it will ask you for
information (name, address, ...) to keep a database of NSSDC users.
NSSDC also provides the following software to display the images:
o IMDISP (IBM PC)
o Browser (Macintosh)
o Pixel Pusher (Macintosh)
o True Color (Macintosh)
The Magellan CD-ROMs will also be available at the anonymous ftp
site at the Ames Research Center: ames.arc.nasa.gov [128.102.18.3].
The Ames site has two CD-ROM drives and they are accessible through
the pub/SPACE/CDROM and pub/SPACE/CDROM2 directories.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Give people a second
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | chance, but not a third.
|_____|/ |_|/ |_____|/ |
Article: 2442
Newsgroups: sci.space.news
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Subject: Magellan Atlas Program
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Date: Fri, 13 Nov 1992 00:56:38 GMT
==========================
MAGELLAN ATLAS PROGRAM
November 12, 1992
==========================
An updated version of the Magellan Atlas program has been released by the
Magellan project. This program was designed to be used with the Magellan
CDROMs. This program will do the following:
o Find the latitude/longitude of named features on Venus
o Given a latitude/longitude, find the mosaics which lie atop
that point and the Magellan CDROMs on which they are found.
o The named feature descriptions includes a short description
of the meaning (origin) of the name, and adds the diameter and
crater type information listing in Schaber's "JGR - Planets"
article of August 25, 1992. Diameters for some coronae are also
listed.
o Find all the named features (numbering 824) which lie in (or on) a
specific mosaic has been added, in order to help those who wish to
work with a specific CD-ROM or mosaic. (This should be helpful
to teachers, who may have only a limited set of CD-ROMs.)
o The atlas now includes CDROMs up through Volume 66 including the
newly released CD-ROMs.
o A new capability has been added to find named features inside a
chosen latitude/longitude rectangle.
The new feature of finding named features inside an arbitrary
latitude/longitude rectangle is intended to show whether a feature which has
been located on a mosaic possesses a name. The rectangle can be a single
latitude/longitude "point" - features whose maximum and minimum coordinates
overlap the point will be found. The rectangle can also wrap around the 360
longitude boundary. For example, to find all features near 0 longitude, one
could search for latitude between +90 and -90 and longitude between 355 and
365. Features near the equator could be found by searching latitude from
+5 to - 5, longitude from 0 to 360.
There is both an IBM PC and Macintosh version of the Magellan Atlas
program. The programs are available using anonymous ftp at:
ftp: ames.arc.nasa.gov (128.102.18.3)
user: anonymous
cd: pub/SPACE/SOFTWARE
files: magellan.zip (IBM PC version -> PKZIP)
magellan.sit (Macintosh version -> STUFFIT, MacBinary format)
magellan.hqx (Macintosh version -> BINEX -> STUFFIT)
The database files used by the Magellan Atlas program are also available.
A description of each field is included at the beginning of each file.
The underlying databases include the center latitude/longitude given in
Schaber's article also, but they are not displayed by the atlas program to
avoid confusion. Also, two new data fields have been added, the first and last
orbit numbers included in a mosaic. The capability of finding products by
orbit number is not available in the "Magellan" program itself, but the data
is available in the database files. The database files are available at:
ftp: ames.arc.nasa.gov (128.102.18.3)
user: anonymous
cd: pub/SPACE/MAGELLAN
files: names.txt (ASCII)
midr.txt (ASCII)
mgn-dbf.zip (2 DBase files -> PKZIP)
#####
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Give people a second
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | chance, but not a third.
|_____|/ |_|/ |_____|/ |
Article: 28627
Newsgroups: sci.astro
From: pgf@mit.edu (Peter G. Ford,601,6485,6610868)
Subject: Re: Magellan image reader for mac
Sender: news@athena.mit.edu (News system)
Organization: MIT Center for Space Research
Date: Fri, 13 Nov 1992 15:30:12 GMT
NASA's Planetary Data System has made the changes to the popular (and
free) NIH Image application necessary to access Magellan images. It is
distributed on one of the Magellan disks - MG_3001 (Global Altimetry
and Radiometry Image Data Record) - in the binhex/stuffit archive file
"software/mac/image.hqx". This file is also available via anonymous ftp
from the following Internet hosts:
server address file
---------------------------------------------------------
starhawk.jpl.nasa.gov 137.79.108.113 pub/image4pds.hqx
delcano.mit.edu 18.75.0.80 mgn/bin/image.hqx
Copy the file to your Macintosh in ASCII mode, run the Stuffit program
to unpack the "Image4pds" application and MS-WORD documentation, read
the documentation (but we don't insist), and run the program. Display
Magellan images by choosing "Open..." from the "File" menu, selecting
one of the ".lbl" files from a Magellan CD-ROM. Don't select an ".img"
file or use the "Import..." method for Magellan images.
Peter G. Ford
MIT and Magellan Project
|
| 456.515 | Updates - November 13-23 | VERGA::KLAES | All the Universe, or nothing! | Wed Nov 25 1992 17:59 | 130 |
| Article: 2458
Newsgroups: sci.space.news
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Subject: Magellan Update - 11/13/92
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Date: Sat, 14 Nov 1992 11:52:19 GMT
Forwarded from the Magellan Project
MAGELLAN STATUS REPORT
November 13, 1992
1. Magellan continues to operate normally, performing a
starcal (star calibration) and desat (desaturation of
the reaction wheels) on each orbit and transmitting a
carrier plus 40 bps X-band signal.
2. On Wednesday Magellan ended its period of apoapsis
occultations in which it passed through the shadow of
Venus on each orbit. Temperatures are expected to
increase gradually, requiring adjustment of the radar
heaters and the length of "hides" (periods in the shadow
of the High Gain Antenna).
3. The craft has completed 6086 orbits of Venus. So far in
Cycle 4 the spacecraft has completed 450 orbits which is
almost exactly 25% of the orbits in a 243 cycle.
4. The gravity data collected during the first ten days of
Cycle 4 was affected by some residual effects of the Orbit
Trim Maneuver to lower the periapsis, so the Mission
Planning Team has recommended extending the gravity data
collection to May 25, 1993.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Give people a second
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | chance, but not a third.
|_____|/ |_|/ |_____|/ |
Article: 2498
Newsgroups: sci.space.news
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Subject: Magellan Update - 11/20/92
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Date: Sat, 21 Nov 1992 07:25:26 GMT
Forwarded from the Magellan Project
MAGELLAN STATUS REPORT
November 20, 1992
1. Magellan continues to operate normally, performing a
starcal (star calibration) and desat (desaturation of
the reaction wheels) on each orbit and transmitting a
carrier plus 40 bps X-band signal.
2. The spacecraft has completed 6136 orbits of Venus; 500 so
far in Cycle 4, which will end on May 25, 1993.
3. Tuesday, November 17, the project conducted a design
review of an aerobraking experiment to be conducted at
the end of Cycle 4. Preliminary modeling of dynamic
pressures, temperatures and attitude control indicate
that circularizing the orbit on an aerobraking plan which
proceeds aggressively for the first several weeks, and
backs off in the later stages, appears to be very feasible.
4. A Spacecraft Team Technical Interchange Meeting (TIM) was
held on Thursday. The spacecraft performance has been
excellent since the last TIM although there have been 12
TWTA (Traveling Wave Tube Ampilfier) SSOs (Spurious Shutoffs),
including five on Tuesday, and there has been some increase
in the slippage of the Solar Array Drive Mechanism since the
end of the apoapsis occultation season.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Learn to recognize the
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | inconsequential, then
|_____|/ |_|/ |_____|/ | ignore it.
Article: 2515
Newsgroups: sci.space.news
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Subject: Magellan Update - 11/23/92
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Date: Tue, 24 Nov 1992 11:40:31 GMT
Forwarded from the Magellan Project
MAGELLAN STATUS REPORT
November 23, 1992
1. Magellan continues to operate normally, transmitting a
carrier plus 40 bps X-band signal which is precisely
tracked by the DSN (Deep Space Network) stations to
provide gravity data.
2. The G2325 command sequence was successfully uplinked and
began execution Friday morning. Later this morning, commands
will be sent to change the star pair used for starcals.
3. Early this morning, there was a triple TWTA SSO (spurious
shutoff of the traveling wave tube amplifier). The
spacecraft recovers automatically from these events.
4. The spacecraft has completed 6160 orbits of Venus; 524 so
far in Cycle 4, which will end on May 25, 1993.
5. At 10 am this morning, Dr. David Senske, Magellan Research
Associate, will speak on Magellan's Gravity Mission and
Venus' Geophysical Patterns.
6. A Magellan award ceremony to issue NASA Group Award
certificates will be held Tuesday, Nov. 24, 1992 at 3:00
pm in Von Karman Auditorium.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Learn to recognize the
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | inconsequential, then
|_____|/ |_|/ |_____|/ | ignore it.
|
| 456.516 | Updates - November 30 to December 7 | VERGA::KLAES | I, Robot | Fri Dec 11 1992 15:27 | 143 |
| Article: 2543
Newsgroups: sci.space.news
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Subject: Magellan Update - 11/30/92
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Date: Tue, 1 Dec 1992 05:55:03 GMT
Forwarded from the Magellan Project
MAGELLAN STATUS REPORT
November 30, 1992
1. Magellan continues to operate normally, transmitting a
carrier plus 40 bps X-band signal which is precisely
tracked by the DSN (Deep Space Network) stations to
provide gravity data.
2. The spacecraft continues to operate under the G2325
command sequence. All except two starcals (star
calibrations) over the 4-day holiday were successful.
On board counters indicate the occurance of another
double TWTA (Traveling Wave Tube Amplifier) SSO
(Spurious Shutoff).
3. Spacecraft temperatures remain in the expected range. Bay
7, which contains the CDS (Command Data Subsystem), is at
51 degrees C with a cycle depth of 6 degrees. Transmitter B
is at 52.7 degrees C which is below the temperature where
satisfactory performance at 1200 bps is found.
4. The spacecraft has completed 6211 orbits of Venus; 575 so
far in Cycle 4, which will end on May 25, 1993.
5. Doug Griffith, Project Manager, left Saturday for Nagoya,
Japan, where he will present at paper at the 1993
International Space Symposium.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Learn to recognize the
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | inconsequential, then
|_____|/ |_|/ |_____|/ | ignore it.
Article: 2627
Newsgroups: sci.space.news
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Subject: Magellan Update - 12/04/92
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Date: Thu, 10 Dec 1992 01:13:20 GMT
Forwarded from Doug Griffith, Magellan Project Manager
MAGELLAN STATUS REPORT
December 4, 1992
1. Magellan continues to operate normally, transmitting a carrier
plus 40 bps X-band signal which is precisely tracked by the DSN
(Deep Space Network) stations to provide gravity data.
2. Yesterday the G2339 command sequence was successfully uplinked to
the spacecraft and will begin execution this morning on orbit #6352.
This sequence is similar to the previous two-week control sequences,
but contains a radio science experiment to be performed on Sunday night.
3. Spacecraft temperatures remain in the expected range. Bay 7,
which contains the CDS (Command Data Subsystem), is at 51 degrees C
with a cycle depth of 6 degrees. Transmitter B is at 52.7 degrees C
which is below the temp where satisfactory performance at 1200 bps is
found.
4. The spacecraft has completed 6240 orbits of Venus; 604 so far in
Cycle 4, which will end on May 25, 1993. Cycle 4 is now one-third complete.
5. Doug Griffith, Project Manager, traveled to Nagoya, Japan, where
he presented a paper at the 1993 International Space Symposium. He
will return to Southern California today, and will be back in the
office on Monday, Dec. 7th.
6. The project received a letter from NASA Headquarters assuring
$3.0M for funding of additional processing and archiving of Magellan
science data. In addition to FY93 investigator contracts, the funding
covers radar processing to correct dynamic range and geometric
distortions in Cycle 2 F-BIDRs, the production of 30 additional
compact disks containing mosaicked images, the development of a "tool
kit" for analysis of stereo images, and the completion of data product
deliveries to PDS (Planetary Data Systems) and NSSDC (National Space
Science Data Center).
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | The 3 things that children
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | find the most fascinating:
|_____|/ |_|/ |_____|/ | space, dinosaurs and ghosts.
Article: 2628
Newsgroups: sci.space.news
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Subject: Magellan Update - 12/07/92
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Date: Thu, 10 Dec 1992 01:19:01 GMT
Forwarded from Doug Griffith, Magellan Project Manager
MAGELLAN STATUS REPORT
December 7, 1992
1. Magellan continues to operate normally, transmitting a carrier plus
40 bps X-band signal which is precisely tracked by the DSN (Deep Space
Network) stations to provide gravity data.
2. Late last night, the spacecraft performed a radio science
experiment on orbits #6369 and 6370. For 22 minutes, as the
spacecraft passed behind Venus (as viewed from Earth), Magellan
performed a limb-tracking maneuver. In this way, the received signal
was passing deeper and deeper through the atmosphere of Venus as it
was refracted around the limb.
3. By measuring the attenuation and doppler shift of both the S and
X-band carrier signals, scientists can study to relative abundances of
H2SO4 (sulfuric acid) and CO2 (carbon dioxide), as well as other
measures of the atmosphere.
4. Spacecraft temperatures remain in the expected range. Bay 7, which
contains the CDS (Command Data Subsystem), is at 51 degrees C with a
cycle depth of 65 degrees. During the radio science experiment the
temperature increased somewhat, but stayed below the operational limit
of 55 degrees C. The transmitter B peaked at 52 degrees C.
5. The spacecraft has completed 6263 orbits of Venus; 627 so far in
Cycle 4, which will end on May 25, 1993.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | The 3 things that children
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | find the most fascinating:
|_____|/ |_|/ |_____|/ | space, dinosaurs and ghosts.
|
| 456.517 | Update - December 11 | VERGA::KLAES | I, Robot | Tue Dec 15 1992 14:46 | 39 |
| Article: 2656
Newsgroups: sci.space.news
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Subject: Magellan Update - 12/11/92
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Date: Sat, 12 Dec 1992 05:05:29 GMT
Forwarded from Doug Griffith, Magellan Project Manager
MAGELLAN STATUS REPORT
December 11, 1992
1. Magellan continues to operate normally, transmitting a carrier plus
40 bps X-band signal which is precisely tracked by the DSN (Deep Space Network
stations to provide gravity data.
2. The present command sequence is designed to automatically shift the
telemetry to the 1200 bps rate if the tracking pass is over a 70 m
station, based on the DSN station allocation schedule as of the time
the reference file was prepared. In the event the station assignment
is changed, some telemetry may be lost because the 34 m stations
cannot successfully receive the 1200 bps rate due to the Transmitter B
noise spur.
3. Spacecraft temperatures remain in the expected range. Bay 7, which
contains the CDS (Command Data Subsystem), is at 51 degrees C with a cycle
depth of 65 degrees.
4. The spacecraft has completed 6294 orbits of Venus; 658 so far in
Cycle 4, which will end on May 25, 1993.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | The 3 things that children
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | find the most fascinating:
|_____|/ |_|/ |_____|/ | space, dinosaurs and ghosts.
|
| 456.518 | Update - December 14 | VERGA::KLAES | I, Robot | Wed Dec 16 1992 18:28 | 38 |
| Article: 2669
Newsgroups: sci.space.news
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Subject: Magellan Update - 12/14/92
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Date: Tue, 15 Dec 1992 05:41:43 GMT
Forwarded from Doug Griffith, Magellan Project Manager
MAGELLAN STATUS REPORT
December 14, 1992
1. Magellan continues to operate normally, transmitting a carrier
plus 40 bps X-band signal which is precisely tracked by the DSN
(Deep Space Network) stations to provide gravity data.
2. The spacecraft performs a star calibration and reaction wheel
desaturation on each orbit. Since Friday at this time, it has
performed 21 sets of these operations. Two of the starcals were
partially successful, which means that the star tracker failed to
identify one of the two stars being scanned. All other starcals and
desats were successful.
3. Spacecraft temperatures remain in the expected range. Bay 7,
which contains the CDS (Command Data Subsystem), is at 51.5 degrees C
with a cycle depth of 6 degrees. Transmitter B peaks at 50.6 degrees C.
4. The spacecraft has completed 6315 orbits of Venus; 670 so far in
Cycle 4, which will end on May 25, 1993.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | The 3 things that children
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | find the most fascinating:
|_____|/ |_|/ |_____|/ | space, dinosaurs and ghosts.
|
| 456.519 | Updates - December 21-29 | VERGA::KLAES | I, Robot | Thu Dec 31 1992 17:52 | 98 |
| Article: 2743
Newsgroups: sci.space.news
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Subject: Magellan Update - 12/21/92
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Date: Mon, 28 Dec 1992 15:14:31 GMT
Forwarded from Doug Griffith, Magellan Project Manager
MAGELLAN STATUS REPORT
December 21, 1992
1. The Magellan spacecraft continues to operate normally, performing
a starcal (star calibration) and desat (desaturation of the reaction
wheels) in each 3-hour orbit and transmitting a carrier signal (plus
X-band telemetry) which is precisely tracked by the DSN (Deep Space
Network) stations to extract gravity data.
2. On Sunday, December 20, the spacecraft performed the second radio
science experiment of recent weeks on orbits #6471 and 6472. As the
spacecraft passed behind Venus (as viewed from Earth), Magellan
performed a limb-tracking maneuver on both ingress and egress. In
this way, the received signal passed through the atmosphere of Venus
as it was refracted around the limb.
3. By measuring the attenuation and doppler shift of both the S- and
X-band carrier signals, scientists can study the relative abundances
of H2SO4 (sulfuric acid) and CO2 (carbon dioxide), as well as other
measures of the atmosphere.
4. Following the radio science experiment, controllers turned on the
360 kHz subcarrier and performed a Very Long Baseline Interferometry
(VLBI) experiment for two orbits. Then the spacecraft was commanded
back to the carrier plus X-band mode.
5. Spacecraft temperatures remain in the expected range: Bay 7 is 48
degrees C and Transmitter B is at 51.2 degrees C, with a cycle depth of 1.5
degrees. The commanded position of the Solar Array Drive Mechanism will
be updated today in preparation for the holiday period.
6. The spacecraft has completed 6367 orbits of Venus; 731 so far in
Cycle-4, which will end on May 25, 1993. Cycle-4 is 39.5% complete.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Choose a job you love, and
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | you'll never have to work
|_____|/ |_|/ |_____|/ | a day in your life.
Article: 2758
Newsgroups: sci.space.news
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Subject: Magellan Update - 12/29/92
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Date: Wed, 30 Dec 1992 00:14:00 GMT
Forwarded from Doug Griffith, Magellan Project Manager
MAGELLAN STATUS REPORT
December 29, 1992
1. The Magellan spacecraft continues to operate normally, performing
a desat (desaturation of the reaction wheels) in each 3-hour orbit,
a starcal (star calibration) on every other orbit, and transmitting
a carrier signal (plus X-band telemetry) which is precisely tracked
by the DSN (Deep Space Network) stations to extract gravity data.
2. On Sunday, December 20, the spacecraft performed two radio
occultation experiments. As the spacecraft passed behind Venus (as
viewed from Earth), the S- and X-band signals were carefully monitored
at the DSS-14 station at Goldstone.
3. Magellan performed a limb-tracking maneuver on both ingress and
egress. In this way, the received signal passed through the
atmosphere of Venus as it was refracted around the limb. S-band
communication was maintained through the entire period of occultation.
The X-band signal was tracked partway through both in entry and exit
portions of the occultations.
4. Radio science investigators Dr. Paul Steffes of Georgia Tech, and
Dr. Jon Jenkins of the SETI Institute/NASA Ames Research Center,
expect the data to yield information on the thermal structure and
abundance of sulfuric acid vapor as well as average electron density
profiles of the Venus atmosphere.
5. The spacecraft has completed 6426 orbits of Venus; 790 so far in
Cycle-4, which will end on May 25, 1993. Cycle-4 is 43% complete.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Choose a job you love, and
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | you'll never have to work
|_____|/ |_|/ |_____|/ | a day in your life.
|
| 456.520 | Updates - January 4-11 | VERGA::KLAES | I, Robot | Tue Jan 12 1993 20:42 | 130 |
| Article: 2779
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space.news
Subject: Magellan Update - 01/04/93
Date: 5 Jan 93 01:37:00 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Forwarded from Doug Griffith, Magellan Project Manager
MAGELLAN STATUS REPORT
January 4, 1993
1. The Magellan spacecraft continues to operate normally,
performing a desat (desaturation of the reaction wheels) in each
3-hour orbit, a starcal (star calibration) on every other orbit, and
transmitting a carrier signal (plus X-band telemetry) which is
precisely tracked by the DSN (Deep Space Network) stations to extract
gravity data.
2. The spacecraft is about halfway through a 4-week command sequence
which allowed control of the mission through the holiday period.
3. Air conditioning and power was lost at the Denver Mission Support
Area over this past weekend, so the display terminals were shut down.
Magellan continued to be tracked by the DSN stations, and telemetry on
the status of the spacecraft was monitored and maintained on the
Central Database at JPL.
4. A check of critical data this morning revealed that the Star Data
Invalid Counter had incremented by only three, indicating good
starcals and attitude control. Another triple spurious shutoff of the
TWTA (Traveling Wave Tube Amplifier) occurred this morning, but this has
become routine. Telecommunications are satisfactory, with X-band telemetry
at 1200 bps.
5. The spacecraft has completed 6470 orbits of Venus; 834 so far in
Cycle-4, which will end on May 25, 1993. The midway point of Cycle-4
will be on January 19.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Choose a job you love, and
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | you'll never have to work
|_____|/ |_|/ |_____|/ | a day in your life.
Article: 2786
Newsgroups: sci.space.news
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Subject: Magellan Update - 01/05/93
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Date: Tue, 5 Jan 1993 23:44:00 GMT
Forwarded from:
PUBLIC INFORMATION OFFICE
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIF. 91109. TELEPHONE (818) 354-5011
MAGELLAN STATUS REPORT
January 5, 1993
The Magellan spacecraft continues to operate normally,
orbiting Venus 50 times each week and transmitting a carrier
radio signal which is precisely tracked by the Deep Space Network
stations to extract gravity data.
By analyzing the subtle changes in the Magellan orbit,
scientists are able to map the variations in the interior of the
planet, and compare those variations with surface features.
Unlike Earth, there is a strong correlation between the internal
concentrations of mass at Venus and its surface topography.
Magellan arrived at Venus August 10, 1990 and has completed
6,478 orbits; 842 orbits have been completed so far in this
fourth 243-day cycle which ends on May 25, 1993.
_____
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Choose a job you love, and
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | you'll never have to work
|_____|/ |_|/ |_____|/ | a day in your life.
Article: 2832
Newsgroups: sci.space.news
From: baalke@kelvin.Jpl.Nasa.Gov (Ron Baalke)
Subject: Magellan Update - 01/11/93
Sender: digester@news.arc.nasa.gov
Organization: Jet Propulsion Laboratory
Date: Mon, 11 Jan 1993 18:50:00 GMT
Forwarded from Doug Griffith, Magellan Project Manager
MAGELLAN STATUS REPORT
January 11, 1993
1. The Magellan spacecraft continues to operate normally, orbiting
Venus 50 times per week and transmitting a carrier signal (plus X-band
telemetry) which is precisely tracked by the DSN (Deep Space Network)
stations to extract gravity data.
2. Temperatures remain in the expected range. Bay 7 which contains
the CDS (Command Data Subsystem), is at 46 degrees C with a cycle depth
of 4 degrees. Transmitter B is at 49.2 degrees with a variation of 0.7
degrees.
3. Attitude control continues to be precise. All starcals (star
calibrations) over the weekend were successful with only one partial scan.
4. Magellan has completed 6523 orbits; 887 so far in Cycle-4 which
will end on May 25, 1993.
5. Following the end of Cycle-4, the Magellan mission will begin a
"Transition Experiment" in which the periapsis will be intentionally
lowered to allow the atmospheric drag to slow the spacecraft's
velocity. This aerobraking maneuver will enable the mission planners
to circularize the orbit and gather high-resolution gravity data
closer to the poles of Venus.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Choose a job you love, and
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | you'll never have to work
|_____|/ |_|/ |_____|/ | a day in your life.
|
| 456.521 | MAGELLAN Venus article in February NATIONAL GEOGRAPHIC | VERGA::KLAES | I, Robot | Fri Jan 15 1993 19:05 | 7 |
| The February 1993 issue of NATIONAL GEOGRAPHIC magazine has an
article on the MAGELLAN space probe mission to Venus. Included are
some excellent radar and computer-generated images of the Venerian
surface, and a comparison of the geologies of Venus and Earth.
Larry
|
| 456.522 | Update - January 18 | VERGA::KLAES | I, Robot | Tue Jan 26 1993 17:17 | 36 |
| Article: 2883
Newsgroups: sci.space.news
From: baalke@kelvin.Jpl.Nasa.Gov (Ron Baalke)
Subject: Magellan Update - 01/18/93
Sender: digester@news.arc.nasa.gov
Organization: Jet Propulsion Laboratory
Date: Mon, 18 Jan 1993 23:40:00 GMT
Forwarded from Doug Griffith, Magellan Project Manager
MAGELLAN STATUS REPORT
January 18, 1993
1. The Magellan spacecraft continues to operate normally.
2. All starcals (star calibrations) and desats (desaturation of the
reaction wheels) over the weekend were successful, with two partial scans.
3. The TWTA (Traveling Wave Tube Amplifier) experienced another
spurious shutoff which was corrected automatically. A memory readout
was commanded early this morning to determine the time of the TWTA SSO.
No further commanding is scheduled for today.
4. The Magellan Project continues a systematic process of archiving
its scientific data products and other records. The radar images,
altimetry/radiometry, and gravity data represents a data set many
times the volume of all previous planetary missions, but the process of
distributing this data to the science community has gone extremely well.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Every once in a while,
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | try pushing your luck.
|_____|/ |_|/ |_____|/ |
|
| 456.523 | Magellan Update -- 01/29/93 | PONIL::J_BUTLER | E pur, si muove... | Mon Feb 01 1993 14:23 | 46 |
| Article 2969 of sci.space.news:
Newsgroups: sci.space.news
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From: baalke@kelvin.Jpl.Nasa.Gov (Ron Baalke)
Subject: Magellan Update - 01/29/93
Message-ID: <29JAN199319514672@kelvin.jpl.nasa.gov>
To: sci-space-news@ames.arc.nasa.gov
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Forwarded from Doug Griffith, Magellan Project Manager
MAGELLAN STATUS REPORT
January 29, 1993
1. It was another quiet week for the Magellan spacecraft as it
continues to operate normally transmitting a carrier signal plus
1200 bps X-band telemetry. All temperatures are in the expected range.
2. The spacecraft has completed 6655 orbits of Venus and is now 55%
complete on its gravity data collection in Cycle-4.
3. Dr. Steve Saunders gave a presentation on the results of the
Magellan Venus Mapping Mission at NASA Headquarters on Wednesday,
January 27. It will be aired on NASA Select at a later date.
4. The Project continues its systematic archiving of science data. A
complete validated catalog of data from the first 243-day mapping
cycle has been delivered to the Planetary Data System Central Node at
JPL and to the PDS Geosciences Node at Washington University.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Every once in a while,
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | try pushing your luck.
|_____|/ |_|/ |_____|/ |
|
| 456.524 | Magellan Update -- 02/01/93 | PONIL::J_BUTLER | E pur, si muove... | Wed Feb 03 1993 13:18 | 48 |
| Article 2990 of sci.space.news:
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From: baalke@kelvin.Jpl.Nasa.Gov (Ron Baalke)
Newsgroups: sci.space.news
Subject: Magellan Update - 02/01/93
Keywords: Magellan, JPL
Message-ID: <2FEB199321224419@kelvin.jpl.nasa.gov>
Date: 2 Feb 93 21:22:00 GMT
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Forwarded from Doug Griffith, Magellan Project Manager
MAGELLAN STATUS REPORT
February 1, 1992
1. The Magellan spacecraft is continuing to operate satisfactorily,
collecting gravity science data and performing normal housekeeping
activities such as momentum wheel desaturations and star calibration
scans. The spacecraft continues to provide engineering telemetry at
1200 bps on the X-band downlink.
2. On 2-2-93, the hydrazine propellant tank will be repressurized
which will allow the performance of the thrusters to be restored to
nominal levels.
3. Magellan has completed 6,788 orbits.
4. Dr. Steve Saunders, the Magellan Project Scientist, presented a
Magellan summary to an enthusiastic audience of about 300 at the
University of Wisconsin Geology department on Friday, 1/26/93.
5. An IMAX segment is being filmed in the Magellan science area which
recreates the retrieval of the first data.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Never yell "Movie!" in a
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | crowded fire station.
|_____|/ |_|/ |_____|/ |
|
| 456.525 | Ron Baalke explains fuel tank repressurization | DECWIN::FISHER | I *hate* questionnaires--Worf | Mon Feb 08 1993 15:32 | 26 |
| I asked Ron about the thruster repressurization mentioned in the status report.
Here is his response:
From: US2RMC::"BAALKE@KELVIN.JPL.NASA.GOV" "Ron Baalke" 8-FEB-1993 12:06:25.14
To: decwin::fisher
CC:
Subj: RE: Magellan
Hello Burns,
Magellan carries a small tank of helium at about 3000 psi which is connected
to the main tank. The main tank contains hydrazine and a bladder wall is
used to separate the hydrazine from the helium. The helium used as a
pressurant. When the pyros are blown on the valve connecting the helium to
the main tank, this allows the helium to flow into the bladder in the main
tank, raising the pressure there from about 300 psi to 450 psi.
The higher pressure in the main tank allows more pressure
to be put through the thrusters, as needed. This was all designed in
anticipation of aerobraking maneuvers, which require more vigorous thruster
firings, and in greater numbers.
Regards,
Ron Baalke
|
| 456.526 | Magellan Update -- 02/05/93 | PONIL::J_BUTLER | E pur, si muove... | Mon Feb 08 1993 18:40 | 42 |
| Article 3017 of sci.space.news:
Newsgroups: sci.space.news
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From: baalke@kelvin.Jpl.Nasa.Gov (Ron Baalke)
Subject: Magellan Update - 02/05/93
Message-ID: <8FEB199307515517@kelvin.jpl.nasa.gov>
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Forwarded from Doug Griffith, Magellan Project Manager
MAGELLAN STATUS REPORT
February 5, 1993
1. The Magellan spacecraft continues to operate normally, transmitting
a carrier signal plus 1200 bps X-band telemetry.
2. On Tuesday, the hydrazine tank of the propulsion system was
repressurized in preparation for the orbit trim maneuvers which will
be performed as part of the aerobraking experiment starting in late
May.
3. The spacecraft has completed 6707 orbits of Venus and is now 58%
complete on its gravity data collection in Cycle-4. We are now 108
days away from the start of the Transition Experiment.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Never yell "Movie!" in a
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | crowded fire station.
|_____|/ |_|/ |_____|/ |
|
| 456.527 | Magellan Update -- 02/08/93 | PONIL::J_BUTLER | E pur, si muove... | Thu Feb 11 1993 13:13 | 42 |
| Article 3039 of sci.space.news:
Newsgroups: sci.space.news
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From: baalke@kelvin.Jpl.Nasa.Gov (Ron Baalke)
Subject: Magellan Update - 02/08/93
Message-ID: <10FEB199323135392@kelvin.jpl.nasa.gov>
To: sci-space-news@ames.arc.nasa.gov
Followup-To: sci.space
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Forwarded from Doug Griffith, Magellan Project Manager
MAGELLAN STATUS REPORT
February 8, 1993
1. The Magellan spacecraft continues to operate normally, transmitting
a carrier signal plus 1200 bps X-band telemetry.
2. The spacecraft has completed 6727 orbits of Venus and is now 58%
complete on its gravity data collection in Cycle-4. We are now 105
days away from the start of the Transition Experiment.
3. The Radar Sensor Test Bed has been moved to Bldg. 198 and the
space reconfigured for the Data Management Team. These steps are in
preparation for releasing approximately 1400 Sq. ft. of 230-2nd floor
to the new Rapid Protyping Test Bed.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Never yell "Movie!" in a
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | crowded fire station.
|_____|/ |_|/ |_____|/ |
|
| 456.528 | Magellan Update -- 02/12/93 | PONIL::J_BUTLER | E pur, si muove... | Mon Feb 15 1993 19:04 | 50 |
| Article 3063 of sci.space.news:
Newsgroups: sci.space.news
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From: baalke@kelvin.Jpl.Nasa.Gov (Ron Baalke)
Subject: Magellan Update - 02/12/93
Message-ID: <12FEB199322290371@kelvin.jpl.nasa.gov>
To: sci-space-news@ames.arc.nasa.gov
Followup-To: sci.space
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Forwarded from Doug Griffith, Magellan Project Manager
MAGELLAN STATUS REPORT
February 12, 1993
1. The Magellan spacecraft continues to operate normally, transmitting
a carrier signal plus 1200 bps X-band telemetry.
2. The TWTA (Traveling Wave Tube Amplifier) experienced another spurious
shut-off (SSO) Thursday, which was corrected automatically. A memory readout
was commanded to determine the time of the TWTA SSO.
3. The G3034 command sequence was uplinked late Thursday and began
execution at 11:15 AM PST on Friday. It is a 4-week sequence similar
to the past several loads.
4. The Magellan Project continues a systematic process condensing its
operations and preparing for the Lean Mean Gravity Team phase of the
mission. Approximately 1400 sq. ft. of the MGN MSA (Magellan Mission
Science Area) has been vacated to provide space for the Rapid Prototyping
Test Bed.
5. The spacecraft has completed 6760 orbits of Venus and is now 61%
complete on its gravity data collection in Cycle-4.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Never yell "Movie!" in a
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | crowded fire station.
|_____|/ |_|/ |_____|/ |
|
| 456.529 | Magellan Update -- 02/15/93 | PONIL::J_BUTLER | E pur, si muove... | Tue Feb 16 1993 12:25 | 54 |
| Article 3081 of sci.space.news:
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From: baalke@kelvin.Jpl.Nasa.Gov (Ron Baalke)
Subject: Magellan Update - 02/15/93
Message-ID: <15FEB199321043958@kelvin.jpl.nasa.gov>
To: sci-space-news@ames.arc.nasa.gov
Followup-To: sci.space
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Forwarded from Doug Griffith, Magellan Project Manager
MAGELLAN STATUS REPORT
February 15, 1993
1. The Magellan spacecraft continues to operate normally under the
G3034 command sequence. All starcals (star calibrations) and desats
(desaturation of the reaction wheels) over the weekend were successful.
The spacecraft experienced a triple TWTA (Traveling Wave Tube Amplifier)
SSO (Spurious Shutoff) on Friday, but recovered automatically as in all
recent events.
2. Bay 7 (which contains the CDS (Command Data Subsystem)) is at
43 degrees C with a cycle depth of 4.5 degrees. Other spacecraft temperatures
are also in the expected range.
3. Magellan has completed 6781 orbits of Venus since August 10, 1990.
The spacecraft has traveled about 222 million kilometers (139 million
miles) in its orbital path around Venus, in addition to the 400
million kilometers it traveled getting from Earth to Venus.
4. The Magellan Project continues a systematic process condensing its
operations and preparing for the Lean Mean Gravity Team (LMGT) phase
of the mission. Plans for housing the LMGT in the 230-260 (Science)
area were presented at the Mission Director's meeting on February
9th.
Magellan is 99 days from the end of Cycle 4.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | If you don't stand for
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | something, you'll fall
|_____|/ |_|/ |_____|/ | for anything.
|
| 456.530 | Magellan Update -- 02/19/93 | PONIL::J_BUTLER | E pur, si muove... | Mon Feb 22 1993 19:00 | 70 |
| Article 3115 of sci.space.news:
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From: baalke@kelvin.Jpl.Nasa.Gov (Ron Baalke)
Subject: Magellan Update - 02/19/93
Message-ID: <20FEB199300204363@kelvin.jpl.nasa.gov>
To: sci-space-news@ames.arc.nasa.gov
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Forwarded from Doug Griffith, Magellan Project Manager
MAGELLAN STATUS REPORT
February 19, 1993
1. The Magellan spacecraft is operating normally under the G3043
command sequence. Starcals (star calibrations) and desats (desaturation
of the reaction wheels) continue to be very successful. Spacecraft
temperatures are in the expected range.
2. A Design Review of the Transition Experiment (TEX) was held in
Denver on Thursday. TEX will begin May 25, 1993, with an OTM (Orbit
Trim Maneuver) to lower the periapsis from 170 to 146 km. This will be
followed by a series of small OTMs to "walk in" to the nominal aerobraking
corridor.
3. The aerobraking corridor has been designed to minimize the time
required to achieve a near-circular orbit while keeping below the
temperature and dynamic pressure limits of the spacecraft. The
corridor design also has to take into account the uncertainty and
variability of Venus' atmosphere.
4. Periapsis will be kept within this corridor by enabling OTMs during
the aerobraking period, which is expected to take 70-80 days. The
preloaded OTM parameters provide eight variations to orbit
corrections, four up and four down.
5. During TEX the orbit period is continually shrinking, so the
spacecraft is controlled by a looping sequence which contains a series
of mini-blocks separated by pause periods. The length of the pause
periods are controlled by global variables which can be updated by
ground command.
6. The preparations for TEX are going well. Engineers and mission
planners are confident that the analyses and design have a high
probability of success.
7. A Spacecraft Technical Interchange Meeting was held on Friday in
Denver to review the spacecraft performance since last fall. All
activities have gone very smoothly. There was some discussion of the
upcoming high-rate gyro calibration (March 1993) and the analyses of
differences in solar panel output.
8. Magellan is 95 days from the end of Cycle 4.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | If you don't stand for
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | something, you'll fall
|_____|/ |_|/ |_____|/ | for anything.
|
| 456.531 | Magellan Update -- 02/26/93 | PONIL::J_BUTLER | E pur, si muove... | Mon Mar 01 1993 13:17 | 56 |
| Article 3145 of sci.space.news:
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From: baalke@kelvin.Jpl.Nasa.Gov (Ron Baalke)
Subject: Magellan Update - 02/26/93
Message-ID: <27FEB199300285975@kelvin.jpl.nasa.gov>
To: sci-space-news@ames.arc.nasa.gov
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Forwarded from Doug Griffith, Magellan Project Project
MAGELLAN STATUS REPORT
February 26, 1993
1. The Magellan spacecraft is operating normally under the G3043
command sequence. Starcals (star calibrations) and desats (desaturation
of the reaction wheels) continue to be very successful. Spacecraft
temperatures are in the expected range.
2. During the tracking pass over the Canberra DSN (Deep Space Network)
station Thursday morning, the Magellan telemetry signal was suddenly lost.
The station personnel reported an increased receiver temperature and
speculated that it looked like the uplink was bouncing off the moon.
A quick check by Eileen Dukes of the Spacecraft Team, using a planetary
ephemeris program on her personal computer, verified that the moon had
indeed occulted Venus and the Magellan signal.
3. The Magellan Project has been requested to work with the MESUR
(Mars Environmental Survey) Project in finding facility space on the
second floor of Bldg. 230 to co-locate the MESUR personnel in the
next few months. The Project is working a plan to accommodate this change
with minimal impact to preparations for TEX (Transition Experiment) and
LMGT (Lean Mean Gravity Team).
4. Magellan has completed 6863 orbits of Venus since August 10, 1990.
We are now 88 days from the end of Cycle-4 and the start of the
Transition Experiment.
Magellan is 88 days from the end of Cycle 4.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | If you don't stand for
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | something, you'll fall
|_____|/ |_|/ |_____|/ | for anything.
|
| 456.532 | Magellan Update -- 03/01/93 | PONIL::J_BUTLER | E pur, si muove... | Wed Mar 03 1993 14:40 | 59 |
| Article 3180 of sci.space.news:
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From: baalke@kelvin.Jpl.Nasa.Gov (Ron Baalke)
Subject: Magellan Update - 03/01/93
Message-ID: <2MAR199318015373@kelvin.jpl.nasa.gov>
To: sci-space-news@ames.arc.nasa.gov
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Forwarded from Doug Griffith, Magellan Project Manager
MAGELLAN STATUS REPORT
March 1, 1993
1. The Magellan spacecraft is operating normally under the G3034
command sequence.
2. Late last week, controllers uplinked parameters or a new star pair
to be used for the attitude control system. Then on Friday, the
spacecraft missed both stars on a starcal (star calibration). The limit
on the attitude updates was increased, and this was followed by a series
of successful starcals. But when the innovation bound was reset to
0.07 degrees on Saturday, the next starcal missed both stars. The limit
is presently widened to 0.3 degrees.
3. The Spacecraft Team is analyzing the star calibration parameters to
see if there is some minor error. The swath one starcals produce
attitude updates which average 0.1 deg. This is higher than the
normal setting of the innovation bound. The swath two starcals (which
scan the same two stars in the opposite direction) result in updates
which average only 0.01 deg.
4. The antenna pointing remains sufficiently accurate for the gravity
data collection, and there is little danger of triggering the fault
protection with the increased attitude update limit.
5. Bay 7, containing the CDS (Command Data Subsystem), is at
41 degrees C with a 5-degree cycle depth. Transmitter B is at
51.2 degrees C.
6. Magellan has completed 6886 orbits of Venus since August 10, 1990.
Magellan is 85 days from the end of Cycle 4.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | It's kind of fun to do
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | the impossible.
|_____|/ |_|/ |_____|/ | Walt Disney
|
| 456.533 | Venus globe graphics | PRAGMA::GRIFFIN | Dave Griffin | Thu Mar 04 1993 17:13 | 12 |
| Available from the archives at pragma::public:[nasa]
mgn_venus*.*
There is an info file describing the files in more detail. I do not have
the time (or probably the hardware) to test the integrity of all of these files,
so if there is something wrong with any of them - send me some mail.
- dave
|
| 456.534 | MAGELLAN Venus Globe Animation | VERGA::KLAES | Life, the Universe, and Everything | Fri Mar 05 1993 15:34 | 89 |
| From: DECWRL::"baalke@kelvin.Jpl.Nasa.Gov" "Ron Baalke" 2-MAR-1993
To: sci-space-news@ames.arc.nasa.gov
CC:
Subj: Magellan Venus Globe Animation
================================
MAGELLAN VENUS GLOBE ANIMATION
March 1, 1993
================================
A Venus Globe animation has been released by the Magellan project, and
is available at the Ames Space Archives. The animation consists of 72
frames derived from data from the Magellan CD-ROMs, and has been converted to
different formats so that it can be run on the IBM PC and Macintosh computers.
Additional versions of the animation have been created to run under the
After Dark program. The animation is available using anonymous ftp to:
ftp: ames.arc.nasa.gov (128.102.18.3)
user: anonymous
cd: pub/SPACE/ANIMATION
files:
venus.zip - Venus Globe Animation in FLI format
venus.bmp - Venus Globe Animation in Windows bitmap format,
may be used with After Dark
venus.hqx - Venus Globe Animation, Mac version, Binhex format
venus.cpt - Venus Globe Animation, Mac version, MacBinary
format
venus.txt - Animation Documentation (see below)
A viewer to play the animation on an IBM PC is also available at Ames:
cd: pub/SPACE/SOFTWARE
files:
play.zip
--------------------------------------------------------------------------
venus.txt
The "venus.zip" contains a compressed animated "rotating globe" of
Venus based on the topography (surface elevation) data collected
by NASA's Magellan mission. The animation is in FLI format and consists
of 72 frames of 200x200 pixels every 5 degrees around the planet's equator.
The surface elevation is color coded so that the highest elevations
appear bright, while the lowest appear dark. The colors approximate
the colors actually seen on the surface by the Soviet Venera landers.
The venus.zip file was compressed with PKZIP. The frames were created
by re-projecting the sinusoidal "browse" image of surface topography from
the GxDR CD-ROM of Magellan's data from Cycle 1. Some data from Cycle 2 is
included in this browse image to partly fill gap in Cycle 1 coverage caused
by Superior Conjunction. The dark areas represent regions not yet
mapped at the time the CD-ROM was made.
The "venus.bmp" file is a Windows "bitmap" file which can be used with the
Windows version of "After Dark" with the "Globe" module to create a
rotating, drifting Venus globe similar to the Macintosh version.
There are 2 different versions of the animation for the Macintosh:
"venus.cpt" is in Macbinary, while "venus.hqx" has been "binhexed" so that
it can be transferred as a text file. Both versions have been compressed
with Compact Pro. The color scheme on the Macintosh versions is different
than that on the DOS version. Rather than using the same color lookup
table used on the previous JPL computer flyovers, a 32-color table from
the "NIH Image" was used, which was shifted "down" by one step to make the
background black. The result is to show a "blue planet" which, although not
typical of Venus surface colors, seemed to capture the range of topography
well. The surface elevation has been color coded, with red representing the
highest elevation and blue the lowest. The Macintosh version consists of
72 frames of175x175 pixels, one every 5 degrees around the planet's equator.
The frames were produced similarly to that of the DOS version.
The Macintosh files contains a compressed copy of a PICS "stack" which
can be used with either "NIH Image" or with the "After Dark" screen
saver module "PICS Player". The Macintosh files has been compressed with
the "Compact Pro" program. The de-compressed files can be opened directly
as a "stack" with "Image", and one can modify the size, color lookup table,
or rate or rotation. To use it as a screen saver, select the "PICS Player"
module in "After Dark" and then select this movie as the file to be used.
The altimetry CD-ROM, like all other Magellan CD-ROMs, may be obtained from
NASA's National Space Science Data Center at Goddard Space Flight Center
(request@nssdc.gsfc.nasa.gov).
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | It's kind of fun to do
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | the impossible.
|_____|/ |_|/ |_____|/ | Walt Disney
|
| 456.535 | Where MAGELLAN's parts came from | VERGA::KLAES | Life, the Universe, and Everything | Sat Mar 06 1993 18:04 | 76 |
| Article: 58356
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space
Subject: Re: Jupiter and Venus followons
Date: 6 Mar 1993 04:45 UT
Organization: Jet Propulsion Laboratory
In article <1n8ce4INNktd@access.digex.com> prb@access.digex.com (Pat) writes:
>Whose bus did Magellan use? Mariner derived? I know at that point in
>NASA's mind-set all vehicles were designed based upon previous history
>and commonality.
Here are all of the "spare" parts that Magellan is comprised of:
Medium Gain Antenna - Mariner
High and Low Gain Antennas - Voyager
Equipment Bus - Voyager
Star Scanner Design - IUS (Inertial Upper Stage)
Radio frequency TWTA - Ulysses
Attitude Control Computer - Galileo
CDS (Main Computer) - Galileo
Thruster Rockets - Voyager
Electric Power Dist. Unit - Galileo
Pyrotechnic Control - Galileo
Solid Rocket Motor Design - Space Shuttle PAM
Propellant Tank Design - Space Shuttle Auxiliary Power Unit.
Also, about 45% of the code for the main computer was lifted unchanged from
Galileo.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | It's kind of fun to do
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | the impossible.
|_____|/ |_|/ |_____|/ | Walt Disney
Article: 58358
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space
Subject: Re: Jupiter and Venus followons
Date: 6 Mar 1993 05:12 UT
Organization: Jet Propulsion Laboratory
The Grand Plan for exploring the solar system is a simple four step process:
1. Flyby
2. Orbiter
3. Unmanned Landing
4. Manned Landing
We've already done all four steps with the moon. The other bodies in
the solar system take a little longer because they are farther away,
and they each follow their own individual time scale.
If you look at this closely, you'll realize that the Galileo and
Cassini missions are the second step in the Grand Plan and are the
follow ons to Voyager. With Venus, we sent the flyby missions with
Mariner 2 and Mariner 10; we've done the orbiters with Pioneer Venus
and Magellan, so the next logical step would be to send a lander (the
Soviets have sent landers, but the US hasn't).
The Fast Pluto Flyby mission is the start of the first step for Pluto.
The proposed MESUR mission is step 3 for Mars and will eventually help
pave the way to a manned landing. It may not always be obvious but
there is plan, and it has been in effect for over 30 years.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | It's kind of fun to do
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | the impossible.
|_____|/ |_|/ |_____|/ | Walt Disney
|
| 456.536 | Venus Map to be unveiled | VERGA::KLAES | Life, the Universe, and Everything | Fri Mar 12 1993 17:53 | 67 |
| Article: 3242
Newsgroups: sci.space.news
From: baalke@kelvin.Jpl.Nasa.Gov (Ron Baalke)
Subject: Venus Map
Sender: digester@news.arc.nasa.gov
Organization: Jet Propulsion Laboratory
Date: Fri, 12 Mar 1993 01:58:00 GMT
Forwarded from:
PUBLIC INFORMATION OFFICE
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIF. 91109. TELEPHONE (818) 354-5011
Contact: Jim Doyle/JPL
FOR IMMEDIATE RELEASE March 10, 1993
#1496
A final map of the topography of the surface of Venus will be
presented before the 24th Lunar and Planetary Science Conference in
Houston, Texas, March 15-19 by Magellan Project scientists.
The map was prepared for the Magellan project, managed by NASA's
Jet Propulsion Laboratory, by the Center for Space Research at
Massachusetts Institute of Technology in Cambridge.
The map depicts the shapes of Venusian mountains, canyons and
other surface features with higher resolution than has ever been seen
before on a global scale.
Other new global maps based on Magellan data have also been
produced showing variations in surface properties such as radar
reflectivity, roughness and emissivity -- a measure of how well the
surface radiates heat.
Magellan Project Scientist Dr. Steve Saunders will lead a morning
session on March 15 called "The Geology of Venus: A Tribute to Valery
Barsukov," dedicated to the late Russian planetary scientist.
Other sessions on Monday and Tuesday, March 15-16, will cover
Venus volcanism, tectonics and recently obtained gravity data from
Magellan.
The Magellan spacecraft continues in operation, with about two
months left in its fourth 243-day cycle. The spacecraft has traveled
about 258 million kilometers (160 million miles) in its orbits around
Venus, in addition to the 1.26 billion kilometers (788 million miles)
it traveled from Earth to Venus.
As of March 15, Magellan will have circled Venus 7,889 times
since August 10, 1990; it has collected images of 98 percent of the
planet. There also will have been 1,000 orbits of gravity data
collection. Magellan's research will be presented in four separate
sessions of the four-day conference.
Magellan is managed by JPL for NASA's Office of Space Science and
Applications.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | It's kind of fun to do
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | the impossible.
|_____|/ |_|/ |_____|/ | Walt Disney
|
| 456.537 | Magellan Update -- 03/15/93 | PONIL::J_BUTLER | E pur, si muove... | Tue Mar 16 1993 15:18 | 42 |
| Article 3271 of sci.space.news:
Newsgroups: sci.space.news
Path: nntpd2.cxo.dec.com!pa.dec.com!decwrl!ames!dont-send-mail-to-path-lines
From: baalke@kelvin.Jpl.Nasa.Gov (Ron Baalke)
Subject: Magellan Update - 03/15/93
Message-ID: <16MAR199301465592@kelvin.jpl.nasa.gov>
To: sci-space-news@ames.arc.nasa.gov
Followup-To: sci.space
News-Software: VAX/VMS VNEWS 1.41
Keywords: Magellan, JPL
Sender: digester@news.arc.nasa.gov
Nntp-Posting-Host: kelvin.jpl.nasa.gov
Organization: Jet Propulsion Laboratory
Date: Tue, 16 Mar 1993 01:46:00 GMT
Approved: sci-space-news@ames.arc.nasa.gov
Lines: 23
Forwarded from Doug Griffith, Magellan Project Manager
MAGELLAN STATUS REPORT
March 15, 1993
1. The Magellan spacecraft continues to operate normally, gathering
gravity data in its fourth 243-day cycle of Venus.
2. Magellan has completed 6989 orbits of Venus since August 10, 1990.
3. The spacecraft has traveled about 258 million kilometers (160
million miles) in its orbits around Venus, in addition to the 400
million kilometers (248 million miles) it traveled getting from Earth
to Venus.
Magellan is 71 days from the end of Cycle-4.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Don't ever take a fence
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | down until you know the
|_____|/ |_|/ |_____|/ | reason it was put up.
|
| 456.538 | MAGELLAN Venus Map | VERGA::KLAES | Life, the Universe, and Everything | Fri Mar 19 1993 15:31 | 39 |
| From: DECWRL::"baalke@kelvin.Jpl.Nasa.Gov" "Ron Baalke" 14-MAR-1993
To: sci-space-news@ames.arc.nasa.gov
CC:
Subj: Magellan Venus Map
==========================
Magellan Venus Map
March 14, 1993
==========================
The Magellan Venus map in now available in GIF and JPEG formats. The
Venus map shows the complete altimeter topography coverage from all 3
Magellan radar mapping cycles (24 months of operation) in Mercator
projection. The un-mapped areas are shown in grey filled with the
Pioneer Venus altimeter map. The areas mapped by Magellan are
color-coded, with red marking the highest areas such as Maxwell Mons
and Maat Mons, and blue marking the lowest areas. Synthetic
"shadowing" has also been added to enhance the visibility of features.
This image has been greatly reduced in resolution to permit easy
transmission and display. The full-resolution imagery will be
distributed on a new altimeter/radiometer CD-ROM through the Planetary
Data System and the National Space Science Data Center later in 1993.
The image is available using anonymous ftp to:
ftp: ames.arc.nasa.gov (128.102.18.3)
user: anonymous
cd: pub/SPACE/GIF
files: gtdr.gif
cd: pub/SPACE/JPEG
files: gtdr.jpg
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | It's kind of fun to do
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | the impossible.
|_____|/ |_|/ |_____|/ | Walt Disney
|
| 456.539 | Magellan Update -- 03/19/93 | CXDOCS::J_BUTLER | E pur, si muove... | Tue Mar 23 1993 14:43 | 44 |
| Article: 3312
Newsgroups: sci.space.news
From: baalke@kelvin.Jpl.Nasa.Gov (Ron Baalke)
Subject: Magellan Update - 03/19/93
Sender: digester@news.arc.nasa.gov
Organization: Jet Propulsion Laboratory
Date: Sat, 20 Mar 1993 02:58:00 GMT
Forwarded from Doug Griffith, Magellan Project Manager
MAGELLAN STATUS REPORT
March 19, 1993
1. The Magellan spacecraft is operating normally, performing a desat
(desaturation of the reaction wheels) on every orbit and a starcal
(star calibration) every other orbit. The High Gain Antenna is kept
pointed toward Earth (except during the starcal) in order to acquire
gravity data, especially around periapsis. Engineering telemetry is
being received at 1200 bps.
2. The Magellan Project continues to implement the plan to collocate
50 MESUR (Mars Enviromental Survey project) members on the second floor
of Bldg. 230, while minimizing impact to MGN preparations for TEX
(Transition Experiment) and LMGT (Lean Mean Gravity Team). About half
of the offices being vacated by MGN team members have been cleared, and
the remaining moves will be complete by March 31st. Significant amounts
of excess paper have been eliminated, and unneeded equipment has been
surplused.
3. Several members of the Magellan science team were in Houston,
Texas, this week for the Lunar and Planetary Science Conference. An
Exhibit of Magellan results was presented, as well as technical
papers.
4. Magellan completed its 7000 orbit of Venus shortly before midnight
(PST) on Tuesday. We are now 67 days from the end of Cycle-4 and the
start of the Transition Experiment.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Don't ever take a fence
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | down until you know the
|_____|/ |_|/ |_____|/ | reason it was put up.
|
| 456.540 | Magellan Update -- 03/22/93 | CXDOCS::J_BUTLER | E pur, si muove... | Tue Mar 23 1993 14:44 | 51 |
| Article: 3322
Newsgroups: sci.space.news
From: baalke@kelvin.Jpl.Nasa.Gov (Ron Baalke)
Subject: Magellan Update - 03/22/93
Sender: digester@news.arc.nasa.gov
Organization: Jet Propulsion Laboratory
Date: Mon, 22 Mar 1993 21:56:00 GMT
Forwarded from Doug Griffith, Magellan Project Manager
MAGELLAN STATUS REPORT
March 22, 1993
1. The Magellan spacecraft continues to operate normally, gathering
gravity data in its fourth 243-day cycle of Venus. All starcals (star
calibrations) over the weekend were successful. There was a TWTA
(Traveling Wave Tube Amplifier) spurious shut-off earlier this morning,
which was corrected automatically.
2. There was no commanding of the spacecraft since Friday, and none is
planned for today. Tomorrow the high rate gyro biases will be
uplinked in the preparation for the high rate gyro calibration test
starting Wednesday.
3. Magellan has operated using low rate gyro biases through most of
the mission to date, so it has not been necessary to calibrate the
gyros in high rate mode. But the aerobraking experiment which will
start in late May has a moderate probability of pushing the attitude
control into the range where the high rate mode is needed.
4. The 24th Lunar and Planetary Science Conference in Houston was
attended by several Magellan scientists who presented technical
papers. The Magellan exhibit was of considerable interest to the
conference participants.
5. A memorial session on the Geology of Venus was held on Monday in
tribute to Valery Leonidovich Barsukov, the late director of the V. I.
Vernadsky Institute in Moscow. The session was chaired by J. W. Head
and R. S. Saunders. Academician Basurkov was very active in promoting
international cooperation in planetary exploration and made possible
the sharing of Russian data on Venus exploration.
6. Magellan has completed 7042 orbits of Venus since August 10, 1990.
Magellan is 64 days from the end of Cycle-4.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Don't ever take a fence
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | down until you know the
|_____|/ |_|/ |_____|/ | reason it was put up.
|
| 456.541 | MAGELLAN Venus Map | VERGA::KLAES | Life, the Universe, and Everything | Tue Mar 30 1993 21:16 | 136 |
| Article: 3367
Newsgroups: sci.space.news
From: baalke@kelvin.Jpl.Nasa.Gov (Ron Baalke)
Subject: Magellan Venus Maps
Sender: digester@news.arc.nasa.gov
Organization: Jet Propulsion Laboratory
Date: Tue, 30 Mar 1993 00:33:00 GMT
==========================
Magellan Venus Maps
March 29, 1993
==========================
Three more Magellan Venus maps are now available in GIF and JPEG formats.
These maps are courtesy of Peter Ford from MIT, working on the Magellan
Project. They were made from the altimeter and radiometer data from
all 3 Magellan radar mapping cycles (24 months of operation). The maps
are shown in Mercator projection for the regions of the planet between
69 degrees north and 69 degrees south latitude, and in stereographic
projections for the polar regions. The images have been anti-aliased
in order to make their embedded text readable, and have been reduced to
820x820 pixel, 256 color resolution. Caption files accompanying the
images are also included. The images are available using anonymous ftp
to:
ftp: ames.arc.nasa.gov (128.102.18.3)
user: anonymous
cd: pub/SPACE/GIF
files: gedrp3v2.gif (Microwave Emissivity Map)
gedrp3v2.txt
gsdrp3v2.gif (Average Meter-Scale Slope Map)
gsdrp3v2.txt
gtdrp3v2.gif (Topography Map)
gtdrp3v2.txt
cd: pub/SPACE/JPEG
files: gedrp3v2.jpg (Microwave Emissivity Map)
gedrp3v2.txt
gsdrp3v2.jpg (Average Meter-Scale Slope Map)
gsdrp3v2.txt
gtdrp3v2.jpg (Topography Map)
gtdrp3v2.txt
---------------------------------------------------------------------
gedrp3v2.txt
These maps of Venus show how well various regions of the surface
radiate heat compared to a perfect radiator. They display in color a
quantity called emissivity, observed using a Magellan Synthetic
Aperture Radar (SAR) receiver during its 24 months of systematic
mapping in Venus orbit. Color is used to code the emission efficiency
(see color bar). Red corresponds to the highest, blue to the lowest
values of emissivity. The upper image shows the portion of the planet
between 69 degrees north and 69 degrees south latitude in Mercator
projection; beneath it are the two polar regions covering latitudes
above 44 degrees in stereographic projection. The horizontal
resolution varies with latitude, being determined solely by the
"footprint" of Magellan's high-gain SAR antenna beam. Near the equator
the surface resolution is about 20 kilometers (12.4 miles) but at high
latitudes it degrades to as much as 100 kilometers (62 miles).
Emissivity of the surface is a measure of how well the surface radiates
heat. Higher regions, such as the Maxwell Montes (at top left center)
and Aphrodite Terra (along the equator at right center), usually show
lower values of emissivity than are typical of lower-lying areas. On a
cooler planet, such as Earth or Mars, water or ice might explain the
puzzling observations but at the surface temperature of Venus -- 470
degrees C (878 F) -- neither can be present. Some theories call for
the presence of an electrically-conducting mineral such as pyrite (the
minerals have an electrical field when illuminated by radar); others
suggest a material as yet unidentified that has an extremely low
electrical loss. The data shown here were compiled and analyzed at the
Center for Space Research, Massachusetts Institute of Technology.
---------------------------------------------------------------------
gsdrp3v2.txt
These images display the meter-scale roughness of the Venus surface
(characterized by its root-mean-square average slope), as observed by
the Magellan radar altimeter during its 24 months of systematic
mapping. The lightest shades locate areas having the highest values of
roughness, while darker shades indicate areas that are smoother. The
upper image shows that part of the planet between 69 degrees north and
69 degrees south latitude in Mercator projection; beneath it are the
two polar regions covering latitudes above 44 degrees in stereographic
projection. Easterly longitudes run across the Mercator map from left
to right, and around the periphery of the polar stereographic
projections. Resolution of the surface varies with spacecraft
altitude, being about 10 kilometers near the equator and degrading to
as much as 25 kilometers at high latitudes. Black areas indicate where
data were not obtained by Magellan.
There is a tendency for elevated regions, e.g. the Maxwell Montes (at
top center) and Aphrodite Terra (along the equator at right), to show
steeper meter-scale slopes than are typical of lower-lying areas. The
steeper slopes probably result from disruption of the surface
associated with tectonic activity in these regions. Note the large
2300-kilometer (1400-mile) diameter circular feature (Artemis Chasma)
in the lower right of the Mercator image. This feature is thought to
have been caused by a gigantic plume of heated rock rising from the
planet's interior. The data shown here were compiled and analyzed at
the Center for Space Research, Massachusetts Institute of Technology.
---------------------------------------------------------------------
gtdrp3v2.txt
This map of the topography of Venus was obtained by the Magellan radar
altimeter during its 24 months of systematic mapping. Color is used to
code elevation (see color bar), and simulated shading to emphasize
relief. Red corresponds to the highest, blue to the lowest
elevations. The upper image shows the portion of the planet between 69
degrees north and 69 degrees south latitude in Mercator projection;
beneath it are the two polar regions covering latitudes above 44
degrees in stereographic projection. Height accuracy is better than 50
meters; horizontal ("footprint") resolution of the surface depends on
spacecraft altitude, with a resolution of about 10 kilometers (6 miles)
near the equator and as much as 25 kilometers (15.5 miles) at higher
latitudes. The Magellan altimeter acquired topography data over 98
percent of the planet's surface. Gray areas show the coarser results
from the Pioneer Venus (1978) and Venera 15/16 (1983) radar altimeters,
and indicate where data were not obtained by Magellan. The elevated
region in the north is Ishtar Terra, dominated by Maxwell Montes (the
planet's highest mountains) which rise 11 kilometers (36,000 feet)
above the planetary mean elevation. Southwest of Ishtar are the
highlands of Beta Regio and Phoebe Regio, which are bisected by a major
north-south trending rift zone. The scorpion-shaped feature extending
along the equator between 70 and 210 degrees longitude is Aphrodite
Terra, a continent-like highland that contains several spectacular
volcanoes at its eastern limit: Maat, Ozza and Sapas Montes. The
altimetric data shown here were compiled and analyzed at the Center for
Space Research, Massachusetts Institute of Technology.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Don't ever take a fence
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | down until you know the
|_____|/ |_|/ |_____|/ | reason it was put up.
|
| 456.542 | Venus craters database | VERGA::KLAES | Life, the Universe, and Everything | Thu Apr 01 1993 18:53 | 41 |
| Article: 3378
Newsgroups: sci.space.news
From: baalke@kelvin.Jpl.Nasa.Gov (Ron Baalke)
Subject: Venus Craters Database
Sender: digester@news.arc.nasa.gov
Organization: Jet Propulsion Laboratory
Date: Thu, 1 Apr 1993 17:32:00 GMT
==========================
VENUS CRATERS DATABASE
April 1, 1993
==========================
The latest database of impact craters on Venus is now available at the
Ames Space Archives. The database catalogs all impact craters on the 99
percent of Venus imaged by the Magellan spacecraft. Included are the latitude,
longitude, and diameter of the crater, as well as a classification. The names
given are either formal IAU names or in the process of submission through the
U.S. Geological Survey. This database was assembled by Dr. Gerald Schaber at
the U.S. Geological Survey in Flagstaff, Arizona.
The database is available in two formats. The craters.txt is an ASCII
file with the data in columns separated by spaces. The craters.asc has the
data in comma-delimited format and should permit it to easily be loaded into
any database program.
The files are available using anonymous ftp at:
ftp: ames.arc.nasa.gov (128.102.18.3)
user: anonymous
cd: pub/SPACE/MAGELLAN
files: craters.txt (ASCII version)
craters.asc (Generic database version)
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Don't ever take a fence
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | down until you know the
|_____|/ |_|/ |_____|/ | reason it was put up.
|
| 456.543 | | PRAGMA::GRIFFIN | Dave Griffin | Thu Apr 01 1993 21:36 | 10 |
| The GIF files (maps) and Crater database mentioned in .541 and .542
(respectively) are available from the archive at:
pragma::public:[nasa]
Files named as stated in the note, but have a MGN_ prefix (e.g., mgn_gtdrp3v2.*)
- dave
|
| 456.544 | Magellan Update -- 04/02/93 | PONIL::J_BUTLER | E pur, si muove... | Mon Apr 05 1993 13:55 | 40 |
| Article 3402 of sci.space.news:
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From: baalke@kelvin.Jpl.Nasa.Gov (Ron Baalke)
Subject: Magellan Update - 04/02/93
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Forwarded from Doug Griffith, Magellan Project Manager
MAGELLAN STATUS REPORT
April 2, 1993
1. The Magellan spacecraft is operating normally in Venus orbit,
transmitting a signal which is used to collect gravity data.
2. Preparations for aerobraking continue to go well. Changes to the
on-board attitude control software were uplinked this week and are
being verified by memory readout.
3. Magellan has completed 7122 orbits of Venus and is now 53 days from
the end of Cycle 4 and the start of the Transition Experiment.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Being cynical never helps
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | to correct the situation
|_____|/ |_|/ |_____|/ | and causes more aggravation
| instead.
|
| 456.545 | Keeping MAGELLAN alive | VERGA::KLAES | Life, the Universe, and Everything | Mon Apr 05 1993 20:53 | 39 |
| Article: 34225
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro,alt.sci.planetary
Subject: Keeping Magellan Alive (Was Re: Mars Observer Update - 03/29/93)
Date: 2 Apr 1993 23:08 UT
Organization: Jet Propulsion Laboratory
In article <C4tv82.DJJ@skates.gsfc.nasa.gov> abdkw@stdvax (David Ward) writes:
>$70 million seems awfully high to keep any mission going. Where
>do your numbers come from and is there something I'm missing in
>the translation between planetary spacecraft and Earth orbiters?
The $70 million is an old number used a couple of years ago to fund
Magellan through 7 cycles into 1995. This included DSN resources,
aerobraking lasting about a cycle (200-300 days), a full science team
and operations support and SAR processing of the radar data. The
amount of data already returned has been a bit overwhelming, three
times the amount of all the data returned from all the previous
planetary missions combined.
Now to keep Magellan going this year, only 8 million dollars is need.
The aerobraking has been reduced to about 70 days, the science team
has been reduced, and the operations team has been reduced as well.
The mission is running at a higher risk factor with the reduced
operations team, by the way. The emphasis is now on obtaining the
improved gravity data after the aerobraking, which is much cheaper to
obtain than the radar data. I don't think there is much hope on
getting any more radar data from Magellan, with the primary
transmitter out of commission and a flaky backup transmitter.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Being cynical never helps
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | to correct the situation
|_____|/ |_|/ |_____|/ | and causes more aggravation
| instead.
|
| 456.546 | Magellan Update -- 04/09/93 | PONIL::J_BUTLER | E pur, si muove... | Tue Apr 13 1993 16:50 | 47 |
| Article 3462 of sci.space.news:
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From: baalke@kelvin.Jpl.Nasa.Gov (Ron Baalke)
Subject: Magellan Update - 04/09/93
Message-ID: <9APR199319531314@kelvin.jpl.nasa.gov>
To: sci-space-news@ames.arc.nasa.gov
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Forwarded from Doug Griffith, Magellan Project Manager
MAGELLAN STATUS REPORT
April 9, 1993
1. The Magellan mission at Venus continues normally, gathering
gravity data which will be correlated to surface topography.
Spacecraft performance is nominal.
2. Magellan has completed 7173 orbits of Venus and is now 46 days
from the end of Cycle 4 and the start of the Transition Experiment.
3. The Project has completed the current phase of office
consolidation to assist in the collocation of the MESUR Project on the
230-2nd floor.
4. Preparations for aerobraking continue to go well. As presently
planned, the Transition Experiment will begin with a 785-second Orbit
Trim Maneuver (OTM) on May 26, 1993 during orbit #7626 at about 10:40
AM PDT. This will lower the periapsis from 170 km to 147 km above the
surface of Venus.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Being cynical never helps
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | to correct the situation
|_____|/ |_|/ |_____|/ | and causes more aggravation
| instead.
|
| 456.547 | Magellan to Start Aerobraking in May | PONIL::J_BUTLER | E pur, si muove... | Tue Apr 13 1993 16:52 | 57 |
| Article 3465 of sci.space.news:
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From: baalke@kelvin.Jpl.Nasa.Gov (Ron Baalke)
Subject: Magellan to Start Aerobraking in May
Message-ID: <9APR199320161852@kelvin.jpl.nasa.gov>
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From the "JPL Universe"
April 9, 1993
Magellan will change orbit, attempt aerobraking in May
The Magellan spacecraft, which has mapped the surface of
Venus with imaging radar, will be put into a near-circular orbit
in a process called "aerobraking" beginning in late May, said
Magellan Project Manager Doug Griffith.
Griffith explained the process in a noontime lecture in von
Karman Auditorium March 26. The essence of the aerobraking
process requires the spacecraft"s lowest orbital point,
periapsis, to be placed in the upper Venus atmosphere. That
allows atmosphere-induced "aerodynamic drag" to reduce the
spacecraft velocity and circularize the orbit.
It will be the first time a NASA spacecraft has been
aerobraked at a distant planet, and the experiment is expected to
provide valuable information for future missions.
Magellan, which completed mapping the planet last September,
is making gravity observations in its fourth 243-day cycle around
Venus. At the end of the cycle, on May 25, spacecraft controllers
will perform an orbit trim maneuver to lower Magellan's periapsis
altitude. Aerobraking operations will then start, and the process
is expected to take about 70 days.
The near-circular orbit would be from 200 kilometers to 300
kilometers (124 to 186 miles).
After circularization has been accomplished, Griffith said,
the project will perform high-resolution gravity studies, pending
NASA approval, through October 1994. Funding has been requested
to extend the mission for that period, he said.
###
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Being cynical never helps
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | to correct the situation
|_____|/ |_|/ |_____|/ | and causes more aggravation
| instead.
|
| 456.548 | | SKYLAB::FISHER | That's right...you were there for the grovelling | Tue Apr 13 1993 17:19 | 7 |
| > It will be the first time a NASA spacecraft has been
>aerobraked at a distant planet, and the experiment is expected to
>provide valuable information for future missions.
I guess in a sense, it was done by Pioneer Venus last fall.
Burns
|
| 456.549 | Magellan Seminar on NASA Select 4/21/93 | PONIL::J_BUTLER | E pur, si muove... | Wed Apr 21 1993 13:58 | 44 |
| Article 3514 of sci.space.news:
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From: baalke@kelvin.Jpl.Nasa.Gov (Ron Baalke)
Subject: Magellan Seminar on NASA Select
Message-ID: <16APR199321092841@kelvin.jpl.nasa.gov>
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The following has been re-scheduled for NASA Select TV, uplinked from JPL:
Magellan Science Seminar (replay - taped April 14, 1993)
Wednesday, April 21, 1993
12:00 noon - 1:00 p.m. PDT (3:00 p.m. - 4:00 p.m EDT)
Speaker: Dr. Thomas W. Thompson
Magellan Science Manager
Topic: "Summary of Magellan Results"
Synopsis: Magellan is revealing unusual and interesting features on Venus
from its tectonic styles to its volcanic and impact crater
forms.
NASA Select TV is carried on GE Satcom F2R, transponder 13,
C-Band, 72 degrees West Longitude, transponder frequency is 3960
MHz, audio subcarrier is 6.8 MHz, polarization is vertical.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | The aweto from New Zealand
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | is part caterpillar and
|_____|/ |_|/ |_____|/ | part vegetable.
|
| 456.550 | Magellan Update -- 04/16/93 | PONIL::J_BUTLER | E pur, si muove... | Wed Apr 21 1993 14:01 | 44 |
| Article 3532 of sci.space.news:
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From: baalke@kelvin.Jpl.Nasa.Gov (Ron Baalke)
Subject: Magellan Update - 04/16/93
Message-ID: <19APR199320243068@kelvin.jpl.nasa.gov>
To: sci-space-news@ames.arc.nasa.gov
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Forwarded from Doug Griffith, Magellan Project Manager
MAGELLAN STATUS REPORT
April 16, 1993
1. The Magellan mission at Venus continues normally, gathering gravity
data which provides measurement of density variations in the upper
mantle which can be correlated to surface topography. Spacecraft
performance is nominal.
2. Magellan has completed 7225 orbits of Venus and is now 39 days from
the end of Cycle-4 and the start of the Transition Experiment.
3. No significant activities are expected next week, as preparations
for aerobraking continue on schedule.
4. On Monday morning, April 19, the moon will occult Venus and
interrupt the tracking of Magellan for about 68 minutes.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | The aweto from New Zealand
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | is part caterpillar and
|_____|/ |_|/ |_____|/ | part vegetable.
|
| 456.551 | Magellan Update -- 04/23/93 | PONIL::J_BUTLER | E pur, si muove... | Mon Apr 26 1993 13:43 | 53 |
| Article 3546 of sci.space.news:
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From: baalke@kelvin.Jpl.Nasa.Gov (Ron Baalke)
Subject: Magellan Update - 04/23/93
Message-ID: <23APR199320331733@kelvin.jpl.nasa.gov>
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Forwarded from Doug Griffith, Magellan Project Manager
MAGELLAN STATUS REPORT
April 23, 1993
1. The Magellan spacecraft continues to operate normally, gathering
gravity data to plot the density variations of Venus in the
mid-latitudes. The solar panel offpoint was returned to zero degrees
and spacecraft temperatures dropped 2-3 degrees C.
2. An end-to-end test of the Delayed Aerobraking Data readout
process was conducted this week in preparation for the Transition
Experiment. There was some difficulty locking up to the data frames,
and engineers are presently checking whether the problem was in
equipment at the tracking station.
3. Magellan has completed 7277 orbits of Venus and is now 32 days
from the end of Cycle 4 and the start of the Transition Experiment.
4. Magellan scientists were participating in the Brown-Vernadsky
Microsymposium at Brown University in Providence, RI, this week. This
joint meeting of U.S. and Russian Venus researchers has been
continuing for many years.
5. A three-day simulation of Transition Experiment aerobraking
activities is planned for next week, including Orbit Trim Maneuvers
and Starcal (Star calibration) Orbits.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | The aweto from New Zealand
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | is part caterpillar and
|_____|/ |_|/ |_____|/ | part vegetable.
|
| 456.552 | Magellan Update -- 04/30/93 | PONIL::J_BUTLER | E pur, si muove... | Tue May 04 1993 19:00 | 70 |
| Article 3678 of sci.space.news:
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From: baalke@kelvin.Jpl.Nasa.Gov (Ron Baalke)
Subject: Magellan Update - 04/30/93
Message-ID: <4MAY199315513977@kelvin.jpl.nasa.gov>
To: sci-space-news@ames.arc.nasa.gov
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Forwarded from Doug Griffith, Magellan Project Manager
MAGELLAN STATUS REPORT
April 30, 1993
1. The Magellan spacecraft continues to operate normally, gathering
gravity data to plot the density variations of Venus in the
mid-latitudes.
2. Gyro A1 began to show increase in motor current and bias error
last weekend. On Monday, gyro B1 was powered up, and after a day of
verifying its performance, a gyro swap was commanded.
P.S. Sunday, 5/2/93, noon update: Due to additional increases in
Gyro A1 motor currents over the weekend, personnel were called in to
turn Gyro A1 off at 10:30 A.M. PDT on Sunday, 5/2/93. Magellan
continues to operate nominally on the minimum required two gyros, that
now being the A2 and B1 pair. However, problems have now been
experienced with the other redundant gyros, the A1 and B2 pair.
3. A three-day interteam operations simulation of aerobraking was
conducted this week. It successfully demonstrated the readiness of
the Magellan Flight Team for the Transition Experiment which will
start May 25th.
4. Yesterday an aerobraking atmospheric test was successfully
conducted in which the spacecraft is maneuvered to the attitude for
the drag pass during the Transition Experiment.
5. At the NASA Award Ceremony on Friday, April 30, several present
and former Magellan team members were honored: Phil Allin, Nick
Climes, Anne-Marie Krause, Steve Ogle, Jon Osoro, Gene Reiz, Ellen
Stofan, Linda (Granata) Welz; from Hughes, Bob Mullen, Howard
Nussbaum; from Martin Marietta: Owen Short, Kenny Starnes.
6. A second aerobraking atmospheric test will be conducted Monday,
May 3.
7. On Tuesday, May 4, Magellan will celebrate its 4th operational year
since launch.
8. On Thursday, May 6, Magellan will celebrate its 1000th day of
Venus orbital operations. At 9:33 AM PDT (the time of Venus Orbit
Insertion), Magellan will have completed 7374.378 orbits.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Once a year, go someplace
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | you've never been before.
|_____|/ |_|/ |_____|/ |
|
| 456.553 | Magellan/DSN Radio Science | PONIL::J_BUTLER | E pur, si muove... | Mon May 10 1993 13:41 | 110 |
| Article 3709 of sci.space.news:
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From: baalke@kelvin.Jpl.Nasa.Gov (Ron Baalke)
Subject: Magellan's Radio Science Experiments
Message-ID: <7MAY199320405277@kelvin.jpl.nasa.gov>
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From the "JPL Universe"
May 7, 1993
Magellan, DSN join forces on radio science experiments
JPL's Deep Space Network (DSN) has joined forces with the
Magellan spacecraft in performing three types of radio science
experiments.
Magellan, which has been orbiting Venus since August 1990
and has mapped more than 98 percent of the planet, has utilized
its downlink capabilities to probe Venus' upper atmosphere and
the sun's plasma. Using open-loop receivers at the DSN stations,
signals were received from the spacecraft, digitized and recorded
on tape.
"The radio science instrument, which is comprised of a
transmitter aboard the spacecraft and a ground-based receiver, is
unique because it is distributed between the spacecraft and DSN
stations; it is at the latter where the data observables are
actually generated," explained Dr. Nick Renzetti, manager of the
Telecommunications and Data Acquisition Science Office.
"Six Magellan radio science experiments have been conducted
over the last two years," said Magellan Project Manager Doug
Griffith. "Three of them studied the atmosphere of Venus, one is
an ongoing gravity-field data-collection campaign, and the other
two have studied the scintillations in the solar wind and the
Faraday rotation effect in the solar corona," he said.
(Scientists can discern the nature of the corona's magnetic field
by understanding how much a signal polarization rotates.)
"Magellan's large High Gain Antenna and powerful X- and
S-band downlink, as well as its ability to accurately maneuver to
track the Earth through the refracting atmosphere, allowed radio
occultation measurements deeper than ever before into Venus'
atmosphere," explained Dr. Steve Saunders, Magellan project
scientist.
When the radio signal transmitted by the spacecraft traveled
through Venus' atmosphere on its way to Earth -- a geometrical
configuration called occultation -- it was changed in phase and
attenuated in amplitude by the gases forming Venus' atmosphere.
These perturbations were recorded by specialized equipment at the
DSN stations. The data produced highly accurate profiles of
atmospheric refractivity and absorptivity that, in turn, produced
temperature and pressure profiles of the Venusian atmosphere. Of
special interest to investigators Paul Steffes of Georgia Tech
University and Jon Jenkins of NASA's Ames Research Center is a
study of the abundance of sulfur dioxide, carbon dioxide and
sulfuric acid vapor in the Venusian atmosphere.
In order for the DSN to remain in communication with the
spacecraft, even as it went behind the planet, Griffith said "a
complicated limb-track maneuver was performed to maintain the
radio link as long as possible while the signal was refracted in
the atmosphere." The maneuver, he said, which was designed and
implemented jointly by JPL's Magellan team and the spacecraft
team at Martin Marietta -- in combination with the strength of
the transmitted signal and accurate predictions of the DSN
receiving equipment -- enabled Venus' atmosphere to be probed to
depths of 35 kilometers at the 3.6 centimeter wavelength radio
signal (X-band) and 33 kilometers at the 13 centimeter signal
(S-band).
During superior conjunction in late spring 1992, a
four-month solar-wind radio-scintillation experiment was
conducted to investigate the near-sun solar-wind region not yet
explored by direct spacecraft, according to Principal
Investigator Richard Woo of the Radio Frequency and Microwave
Subsystems Section. For part of the experiment, data were also
generated to study the Faraday rotation effect in the solar
corona. Michael Bird of Germany's University of Bonn will obtain
information about the electron density and magnetic field in the
corona.
In its current cycle around Venus, Magellan and the DSN --
in a third investigation -- are measuring the planet's
gravitational field. Accelerations of the spacecraft are tracked,
according to gravity field investigator William Sjogren of the
Navigation Systems Section. Using the DSN to communicate with the
spacecraft and record the returned signals, small changes in the
X- and S-band Doppler signatures can be seen. (The Doppler effect
is the change in frequency due to relative motion of either the
transmitter or receiver.) These changes are caused by
perturbations in the spacecraft's orbit that result from
irregularities in the mass distribution of the planet.
"The gravity data will allow geophysical models to examine
the internal structure and dynamics of Venus, as well as look
below the surface for the forces that have created the geologic
features that Magellan has mapped," Saunders said.
###
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Once a year, go someplace
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | you've never been before.
|_____|/ |_|/ |_____|/ |
|
| 456.554 | Magellan Update -- 05/07/93 | PONIL::J_BUTLER | E pur, si muove... | Mon May 10 1993 13:42 | 47 |
| Article 3711 of sci.space.news:
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From: baalke@kelvin.Jpl.Nasa.Gov (Ron Baalke)
Subject: Magellan Update - 05/07/93
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Forwarded from Doug Griffith, Magellan Project Manager
MAGELLAN STATUS REPORT
May 7, 1993
1. The Magellan spacecraft continues to operate normally, gathering
gravity data to plot the density variations of Venus in the
mid-latitudes.
2. The final command sequence of Cycle 4 was uplinked and went active
Friday morning. Battery reconditioning was also started on Friday morning.
3. Tuesday, May 4th, marked the fourth anniversary of the Magellan launch.
4. An Operations Readiness Review for the Transition Experiment will
be held on Thursday, May 13th, to assess preparations for aerobraking.
5. On Friday, May 14th, Magellan will pass the nominal end of Cycle 4.
The cycle was extended by 10 days to re-acquire gravity data which
was affected by passage of the radio signal through the atmosphere of
Venus early in the cycle.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Once a year, go someplace
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | you've never been before.
|_____|/ |_|/ |_____|/ |
|
| 456.555 | Magellan Update -- 05/14/93 | CXDOCS::J_BUTLER | E pur, si muove... | Tue May 18 1993 13:53 | 38 |
| Article: 3751
Newsgroups: sci.space.news
From: baalke@kelvin.Jpl.Nasa.Gov (Ron Baalke)
Subject: Magellan Update - 05/14/93
Sender: digester@news.arc.nasa.gov
Organization: Jet Propulsion Laboratory
Date: Sat, 15 May 1993 04:42:00 GMT
Forwarded from Doug Griffith, Magellan Project Manager
MAGELLAN STATUS REPORT
May 14, 1993
1. The Magellan spacecraft continues to operate normally, gathering
gravity data to plot the density variations of Venus in the
mid-latitudes.
2. Battery reconditioning was completed on Friday, May 14th.
3. Friday, May 14th, marked the nominal end of Cycle-4. The cycle
was extended by 10 days to re-acquire gravity data which was affected
by passage of the radio signal through the atmosphere of Venus early
in the cycle.
4. An Operations Readiness Review for aerobraking was held Thursday,
May 13th. Several action items were identified, but all indications
were that the spacecraft and flight team are ready to begin the
Transition Experiment (TEX) on May 25th.
5. A follow-up TEX Operations Simulation will be conducted on May
19th.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Once a year, go someplace
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | you've never been before.
|_____|/ |_|/ |_____|/ |
|
| 456.556 | MAGELLAN to test Venerean aerobraking | VERGA::KLAES | Life, the Universe, and Everything | Tue May 18 1993 20:12 | 100 |
| From: US1RMC::"baalke@kelvin.Jpl.Nasa.Gov" "Ron Baalke" 18-MAY-1993
To: sci-space-news@ames.arc.nasa.gov
CC:
Subj: Magellan to Test Aerobraking in Venus Atmosphere
Paula Cleggett-Haleim
Headquarters, Washington, D.C.
(Phone: 202/358-1547)
Franklin O'Donnell
Jet Propulsion Laboratory, Pasadena, Calif.
(Phone: 818/354-5011)
RELEASE: 93-89
MAGELLAN TO TEST AEROBRAKING MANEUVER IN VENUS ATMOSPHERE
NASA's Magellan spacecraft will dip into the atmosphere of Venus
beginning May 25 in a first-of-its-kind "aerobraking" maneuver, lowering the
spacecraft's orbit to start a new experiment.
The aerobraking technique will use the drag created by Venus'
atmosphere to slow the spacecraft and circularize Magellan's orbit. Currently
Magellan is looping around Venus in a highly elliptical orbit.
"This aerobraking technique has never been used before on a NASA
planetary mission," said Douglas Griffith, Magellan project manager at NASA's
Jet Propulsion Laboratory, Pasadena, Calif.
"Magellan has been highly successful in completing all of its primary
mission goals," said Alphonso V. Diaz, Deputy Associate Administrator for
NASA's Office of Space Science. "The new orbit will enhance the scientific
return from what is already one of NASA's most successful space science
missions."
According to Griffith, aerobraking is the only way to make such a large
change in Magellan's orbit because the spacecraft does not have enough thruster
fuel onboard for the change. "Although aerobraking creates some risk of losing
the spacecraft, the scientific benefits make the risk worthwhile," he said.
The benefit of changing the orbit is to make possible better
measurements of Venus's gravity field, particularly at latitudes near the
planet poles, said Dr. R. Stephen Saunders of JPL, the Magellan Project
Scientist.
For the past 8 months, Magellan has been collecting data on Venus'
gravity. However, measurements from the current elliptical orbit are blurred
at high latitudes by the height of the spacecraft above the surface -- about
1,300 miles (2,100 kilometers) near the north pole and 1,700 miles (2,800
kilometers) near the south pole.
Scientists also hope to study Venus's atmosphere using data collected
during the aerobraking experiment itself. And another objective is to gain the
engineering experience that may allow future missions to use aerobraking to
enter planetary orbit or to change orbit without using large thrusters.
Launched in May 1989, Magellan will complete its fourth 243-day orbital
cycle at Venus on May 25. During each of the 8-month cycles, Magellan orbits
from north to south while the planet turns once underneath the spacecraft.
During earlier cycles, Magellan used its radar to map Venus's surface
with a resolution as fine as 250 feet (75 meters). Data was obtained on the
elevation slope, radar reflectivity and radar emissivity over 98 percent of
the planet.
In the upcoming maneuver, flight controllers hope to lower the
spacecraft from a low point near 100 miles (170 kilometers) and high point of
5,300 miles (8,500 kilometers). The target orbit is 125 by 375 miles (200 by
600 kilometers). This would alter orbit time from 3-1/4 hours to 90 minutes.
The aerobraking experiment will start at 1:30 p.m. EDT May 25, when the
spacecraft makes the first maneuver. By controlling the orbit altitude, the
drag and heat generated on the spacecraft will be kept within tolerable limits.
Completing the change will take about 80 days. The short period of
drag on each orbit, a few minutes at the start to about 20 minutes near the
end, will lower the orbital high point by about 6 miles (10 kilometers) on
every orbit.
Measuring Venus's gravity field permits scientists to measure the
pattern of heavier and lighter regions under the planet's surface. It is the
only technique currently possible to look inside Venus and provides
information like that gained using seismometers to probe inside a planet.
Similar measurements on Earth helped reveal plate tectonics, Earth's
fundamental geologic process.
"Without better measurements from a lower orbit, it would remain very
hard to understand Venus's internal geology and why it is so different from
Earth," said Saunders.
JPL manages the Magellan mission for NASA's Office of Space Science,
Headquarters, Washington, D.C.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Never laugh at anyone's
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | dreams.
|_____|/ |_|/ |_____|/ |
|
| 456.557 | RE 456.556 | VERGA::KLAES | Life, the Universe, and Everything | Wed May 19 1993 21:03 | 56 |
| Article: 63058
Newsgroups: sci.space
From: seale@possum.den.mmc.com (Eric H Seale)
Subject: Re: Magellan to Test Aerobraking in Venus Atmosphere
Sender: news@den.mmc.com (News)
Organization: Martin Marietta Astronautics, Denver
Date: Wed, 19 May 1993 15:52:33 GMT
baalke@kelvin.jpl.nasa.gov (Ron Baalke) writes:
>... There is some
>risk involved with the aerobraking. The spacecraft will experience some
>heating as it passes through the atmosphere, most of which will be
>dissipated through the solar arrays and the back of the High Gain Antenna.
>The aerobraking will not only help circularize the orbit, but valuable data
>will also be collected on the aerobraking itself that can be used by
>future missions.
Other risks of aerobraking:
1) On the drag passes, the spacecraft will see a substantial flux of
high-energy atomic-oxygen. There is some concern as to the effects
of this on the spacecraft's surface (in particular, on the electrical
interconnects between cells in the solar panels).
2) Aerodynamic torques during aerobraking passes will be considerable.
The aerobraking attitude itself is aerodynamically stable, but if
some (say, hardware) problem arises on the spacecraft during
aerobraking, and the spacecraft tries to "call home" for help, it is
considered doubtful that the spacecraft could maintain an Earth-
pointed attitude over an orbit.
3) Venus' atmosphere is not as well-characterized as the Earth's.
Particularly during the "end-game" where Magellan's orbit is rapidly
approaching its circular "target", any unpredicted (and
unpredictable) "blooms" in the atmosphere could cause serious
problems.
The long and the short of it: aerobraking is doable, but not without
risk. Most folks I've talked to feel Magellan will be skating pretty
close to the cliff, but probably far enough away to pull this off.
The biggest concern is that this scheme leaves no margin for error --
any hardware failures during aerobraking, and Magellan's goose is
probably cooked (figuratively and literally).
Of course, Congress is getting bored with Magellan anyway (now let's
see -- if a program fails, they whine because of the failure; if a
program succeeds, they whine because they have to keep funding it...
;-) ). My understanding is that without aerobraking, Magellan's
operations funding would have been cancelled anyway, and the bird
would have been turned off. If Magellan doesn't make it through
aerobraking in one piece, at least she'll go down with her boots on.
Eric Seale
seale@pogo.den.mmc.com
|
| 456.558 | Magellan Update -- 05/21/93 | CXDOCS::J_BUTLER | E pur, si muove... | Fri May 21 1993 20:49 | 44 |
| Article: 1326
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro,alt.sci.planetary
Subject: Magellan Update - 05/21/93
Date: 21 May 1993 20:19 UT
Organization: Jet Propulsion Laboratory
Forwarded from Doug Griffith, Magellan Project Manager
MAGELLAN STATUS REPORT
May 21, 1993
1. The Magellan spacecraft continues to operate normally as the
mission is just four days from the end of Cycle-4 and the start of the
Transition Experiment (TEX).
2. The Magellan Project Quarterly Review was held on Monday.
3. Meetings of the Science Working Groups and the Project Science
Group were held on Monday and Tuesday.
4. A follow-up TEX Operations Simulation was conducted on May 19th.
Magellan Significant Events for Next Week
1. Cycle-4 will end and the Transition Experiment (TEX) will begin
Tuesday at 10:31 AM PDT with Orbit Trim Maneuver #3. OTM-3 will lower
periapsis to a target altitude of 149.4 km.
2. During the next four days a series of corridor-adjusting OTMs
will lower Magellan into the exact level of the atmosphere for
aerobraking.
3. A Magellan Press Conference at NASA Headquarters will be
broadcast on NASA Select on Wednesday, March 26th, starting at 10:00
AM PST.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Never laugh at anyone's
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | dreams.
|_____|/ |_|/ |_____|/ |
|
| 456.559 | Magellan Update -- 05/25/93 | CXDOCS::J_BUTLER | E pur, si muove... | Wed May 26 1993 03:18 | 52 |
| Article: 1335
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro,alt.sci.planetary
Subject: Magellan Update - 05/25/93 (Aerobraking Started)
Date: 25 May 1993 21:43 UT
Organization: Jet Propulsion Laboratory
Forwarded from:
PUBLIC INFORMATION OFFICE
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIF. 91109. TELEPHONE (818) 354-5011
MAGELLAN STATUS REPORT
May 25, 1993
The Magellan spacecraft was lowered into the top of the
Venus atmosphere today for an "aerobraking" maneuver, the first
of its kind in planetary exploration, to begin the process of
circularizing its highly elliptical orbit.
The operation began at 10:31 a.m. Pacific Daylight Time with
a thruster burn lasting until 10:41 a.m. to slightly slow the
spacecraft. The high-gain antenna was turned toward Earth at
10:54 a.m. and the spacecraft first struck the outer atmosphere
at 12:00 noon. The atmospheric contact on the first orbit lasted
until 12:36 p.m.
The operation, to continue over about 80 days, will slowly
bring the spacecraft from its current orbit ranging between 170
kilometers (105 miles) and 8,500 kilometers (5,300 miles) from
Venus, to a new, more circularized orbit of 200 by 600 kilometers
(125 by 375 miles). The change will alter the time taken by each
orbit from 3 hours, 15 minutes to about 90 minutes.
If the maneuver is successful, the new orbit will permit
high-resolution gravity studies at Venus's poles as well as at
its equatorial latitudes.
The second "drag pass," when the spacecraft will again dip
into the atmosphere to continue the circularizing process, was
scheduled for 3:14 p.m. to 3:50 p.m. PDT today.
#####
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Never laugh at anyone's
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | dreams.
|_____|/ |_|/ |_____|/ |
|
| 456.560 | Magellan Update #2 -- 05/25/93 | CXDOCS::J_BUTLER | E pur, si muove... | Wed May 26 1993 03:19 | 44 |
| Article: 1337
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro,alt.sci.planetary
Subject: Magellan Update #2 - 05/25/93
Date: 25 May 1993 23:00 UT
Organization: Jet Propulsion Laboratory
Forwarded from Doug Griffith, Magellan Project Manager
MAGELLAN STATUS REPORT
May 25, 1993
1. The Magellan spacecraft started its Transition Experiment this
morning at 10:31 AM PDT with an Orbit Trim Maneuver (OTM) which lowered
its periapsis (closest approach to Venus) to 149.4 km.
2. Telemetry indicated that the 11.3 minute burn of the thrusters was
normal, but the spacecraft engineers had to wait another two hours for
the results of the first passage through the upper atmosphere.
3. Following the first atmospheric drag pass, all subsystems were
reported to be nominal. Temperatures are in the expected range and
the attitude control system reports the expected number of gyro
pulses.
4. The target altitude was selected so that the spacecraft would
experience about 20% of the maximum allowable dynamic pressure, so the
temperatures and torques on the spacecraft at this stage are minimal.
5. During the next four days a series of walk-in trim maneuvers will
further lower the periapsis until the spacecraft is in the desired
corridor.
6. This evening, following analysis by the Navigation Team of the
first two orbits of aerobraking, the exact magnitude for the next OTM
will be decided. That corridor-adjustment OTM is scheduled for
5:46 AM PDT tomorrow.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Never laugh at anyone's
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | dreams.
|_____|/ |_|/ |_____|/ |
|
| 456.561 | Magellan Update #3 -- 05/25/93 | CXDOCS::J_BUTLER | E pur, si muove... | Wed May 26 1993 17:19 | 61 |
| Article 3807 of sci.space.news:
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From: baalke@kelvin.Jpl.Nasa.Gov (Ron Baalke)
Subject: Magellan Update #3 - 05/25/93
Message-ID: <26MAY199315521221@kelvin.jpl.nasa.gov>
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Forwarded from Doug Griffith, Magellan Project Manager
MAGELLAN STATUS REPORT
May 25, 1993
8:30 PM PDT
1. The Magellan spacecraft started its Transition Experiment this
morning at 10:31 AM PDT with an Orbit Trim Maneuver which lowered its
periapsis (closest approach to Venus) to 149.4 km.
2. Telemetry indicated that the 11.3 minute burn of the thrusters was
normal, and the resulting periapsis altitude was 149.7 km.
3. Following the first atmospheric drag pass, all subsystems were
reported to be nominal. Temperatures of the solar panels increased by
about 7 to 9 degrees C as a result of atmospheric friction. This is
about half the expected value.
4. The attitude control system generated about 2800 thruster pulses
as the control shifted from reaction wheel control to thrusters and
back during the pass. Much of this activity is caused by the residual
momentum from the wheels being transferred to the body of the craft.
5. Power and Telecom were nominal.
6. Nearly identical telemetry measurements were received following
the next two drag passes (Orbits 7628, 7629).
7. During the next four days a series of walk-in trim maneuvers will
further lower the periapsis until the spacecraft is in the desired
corridor.
8. Based on the present navigation and spacecraft data, the next two
OTMs (Orbit Trim Maneuvers) will be the "double down" magnitude. The
first of the corridor-adjustment OTMs is scheduled for 5:46 AM PDT tomorrow.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Never laugh at anyone's
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | dreams.
|_____|/ |_|/ |_____|/ |
|
| 456.562 | Magellan Update -- 05/26/93 | CXDOCS::J_BUTLER | E pur, si muove... | Thu May 27 1993 14:33 | 54 |
| Article 3812 of sci.space.news:
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From: baalke@kelvin.Jpl.Nasa.Gov (Ron Baalke)
Subject: Magellan Update - 05/26/93
Message-ID: <26MAY199322541069@kelvin.jpl.nasa.gov>
To: sci-space-news@ames.arc.nasa.gov
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Forwarded from Doug Griffith, Magellan Project Manager
MAGELLAN STATUS REPORT
May 26, 1993
3:30 PM PDT
1. The Magellan spacecraft continued its Transition Experiment this
morning at 5:46 AM PDT with another Orbit Trim Maneuver (OTM) which
further lowered its periapsis (closest approach to Venus) to 146.2 km.
2. The spacecraft has now made nine atmospheric drag passes and all
subsystems were reported to be nominal. Temperatures of the solar
panels increased by about 12 to 15 degrees C as a result of
atmospheric friction. They reach a peak of 39 degrees C. (compared to
a design max of about 160 degrees C.)
3. The attitude control system continues to control the position of
the spacecraft during the drag pass by generating thruster pulses as
the control shifted from reaction wheel control to thrusters and back
during the pass. Much of this activity is caused by the residual
momentum from the wheels being transferred to the body of the craft.
4. Power reports that the solar panels generate some small amount of
electricity during the last part of each drag pass.
5. Based on the present navigation and spacecraft data, the next OTM
will be the "double down" magnitude. The second of the
corridor-adjustment OTMs is scheduled for 2:07 PM PDT tomorrow.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Never laugh at anyone's
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | dreams.
|_____|/ |_|/ |_____|/ |
|
| 456.563 | Magellan Update -- 05/27/93 | CXDOCS::J_BUTLER | E pur, si muove... | Wed Jun 02 1993 21:30 | 50 |
| Article: 3815
Newsgroups: sci.space.news
From: baalke@kelvin.Jpl.Nasa.Gov (Ron Baalke)
Subject: Magellan Update - 05/27/93
Sender: digester@news.arc.nasa.gov
Organization: Jet Propulsion Laboratory
Date: Thu, 27 May 1993 20:06:00 GMT
Forwarded from Doug Griffith, Magellan Project Manager
MAGELLAN STATUS REPORT
May 27, 1993
10:00 AM PDT
1. The Magellan Transition Experiment continues as the flight team
carefully maneuvers the spacecraft toward the desired aerobraking
corridor.
2. The spacecraft has now made fifteen atmospheric drag passes with
periapsis below 150 km and all subsystems were reported to be nominal.
3. As the spacecraft approaches the low part of the orbit, the
attitude control system switches from reaction wheel control to the
thrusters. Depending on the amount of attitude error when this switch
occurs, the thrusters have used from 0.013 to 0.023 kg of fuel to
maintain the position within 10! of the velocity vector. The expected
fuel consumption is 0 to 0.3 kg per orbit.
4. Shortly before orbit 7638 last night, an update to the periapsis
time table was sent to Magellan. An error in the coded data was
rejected by the on-board computer, and the spacecraft apparently went
through the atmospheric drag pass in the wrong attitude. Spacecraft
systems responded as designed and there was no damage to the craft.
5. The solar panels were facing the sun and stayed near 60 degrees C.
(instead of cooling to 25 and then warming to 39 during the drag
pass). Attitude control stayed in phase plane D, and used about 0.046
kg of fuel during the pass. From orbit 7639 on the spacecraft
performance has been normal.
6. Based on the present navigation and spacecraft data, the next OTM
(Orbit Trim Maneuver) will be the "double down" magnitude. The second
of the corridor-adjustment OTMs is scheduled for 2:07 PM PDT today.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Never laugh at anyone's
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | dreams.
|_____|/ |_|/ |_____|/ |
|
| 456.564 | Magellan Update #2 -- 05/27/93 | CXDOCS::J_BUTLER | E pur, si muove... | Wed Jun 02 1993 21:31 | 44 |
| Article: 3817
Newsgroups: sci.space.news
From: baalke@kelvin.Jpl.Nasa.Gov (Ron Baalke)
Subject: Magellan Update #2 - 05/27/93
Sender: digester@news.arc.nasa.gov
Organization: Jet Propulsion Laboratory
Date: Thu, 27 May 1993 23:39:00 GMT
Forwarded from Doug Griffith, Magellan Project Manager
MAGELLAN STATUS REPORT
May 27, 1993
3:00 PM PDT
1. The Magellan Transition Experiment continues as the flight team
carefully maneuvers the spacecraft toward the desired aerobraking
corridor. The second "double down" trim maneuver was performed at
2:07 PM PDT today to lower the periapsis to 143 km.
2. At the Mission Director meeting early this afternoon, a "single
down" OTM was approved for execution on Saturday. This will lower
the periapsis by 1.6 km.
3. All spacecraft subsystems continue to report nominal performance.
There have been some difficulties with transfer of 1200 bps telemetry
between JPL and Denver.
4. On the incident of orbit 7638 last night, Attitude Control
estimates that the spacecraft performed the drag pass about 120 deg.
off the proper attitude. Spacecraft systems responded as designed and
there was no damage to the craft.
5. The solar panels were facing the sun and stayed near 85 degrees C.
(instead of cooling to 25 and then warming to 39 during the drag
pass). Attitude control stayed in phase plane D, and used about 0.046
kg of fuel during the pass. From orbit 7639 on the spacecraft
performance has been normal.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Never laugh at anyone's
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | dreams.
|_____|/ |_|/ |_____|/ |
|
| 456.565 | Magellan Update -- 05/28/93 | CXDOCS::J_BUTLER | E pur, si muove... | Wed Jun 02 1993 21:33 | 44 |
| Article: 3823
Newsgroups: sci.space.news
From: baalke@kelvin.Jpl.Nasa.Gov (Ron Baalke)
Subject: Magellan Update - 05/28/93
Sender: digester@news.arc.nasa.gov
Organization: Jet Propulsion Laboratory
Date: Sat, 29 May 1993 00:01:00 GMT
Forwarded from Doug Griffith, Magellan Project Manager
MAGELLAN STATUS REPORT
May 28, 1993
3:00 PM PDT
1. The Magellan Transition Experiment continues to successfully
maneuver the spacecraft toward the desired aerobraking corridor. The
spacecraft has now made 24 atmospheric drag passes with periapsis
below 150 km and all subsystems were reported to be nominal.
Periapsis is presently at 143 km.
2. The performance of the spacecraft during the atmospheric drag
passes as well as analysis of orbital changes continue to indicate an
atmosphere which is 13% above the "Single CO2" model.
3. Currently the solar panel temperature increases by 25 degrees C
during the drag pass, reaching a peak of 47.5 degrees. The design
limit is about 160 degrees. All other spacecraft temps are well
within the expected range.
4. The next OTM (Orbit Trim Maneuver) will be a "single down" scheduled
for Saturday at 10:52 AM PDT. Based on the present navigation predictions,
this would place the spacecraft at the upper edge of the desired corridor.
5. The periapsis altitude will continue to drift downward over the
next week or more, and the first "up" OTM is expected on Sunday, June
6th. Based on orbit changes early next week, the actual OTM will be
placed on Saturday or Monday.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Never laugh at anyone's
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | dreams.
|_____|/ |_|/ |_____|/ |
|
| 456.566 | Magellan Update -- 05/29/93 | TINCUP::J_BUTLER | E pur, si muove... | Thu Jun 03 1993 14:25 | 55 |
| Article 3880 of sci.space.news:
Newsgroups: sci.space.news
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From: baalke@kelvin.Jpl.Nasa.Gov (Ron Baalke)
Subject: Magellan Update - 05/29/93
Message-ID: <1JUN199317205579@kelvin.jpl.nasa.gov>
To: sci-space-news@ames.arc.nasa.gov
Followup-To: sci.space
News-Software: VAX/VMS VNEWS 1.41
Keywords: Magellan, JPL
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Date: Tue, 1 Jun 1993 17:20:00 GMT
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Lines: 36
Forwarded from Doug Griffith, Magellan Project Manager
MAGELLAN STATUS REPORT
May 29, 1993
3:00 PM PDT
1. The Magellan Transition Experiment continues to successfully
maneuver the spacecraft toward the desired aerobraking corridor. The
spacecraft has now made 31 atmospheric drag passes with the periapsis
below 150 km and all subsystems are reported to be nominal.
2. Corridor Orbit Trim Maneuver (COTM) #3 was performed at 10:57 AM
PDT this morning and lowered the periapsis to 141.1 km. The dynamic
pressure at this altitude is 0.23 N/M2. The nominal range for the
desired aerobraking corridor is from 0.25 to 0.32 N/M2.
3. The performance of the spacecraft during the atmospheric drag
passes as well as analysis of orbital changes now indicate an
atmosphere which is 17.5% above the "Single CO2" model.
4. Currently the solar panels increase by 35 degrees C during the
drag pass, reaching a peak of 50 degrees C. The aerobraking limit is
about 160 degrees. The estimated temperature of the HGA is 85 degrees C.
(with a limit of about 180 deg.)
5. The periapsis altitude will continue to drift downward over the
next week or more, and the first "1/2 up" COTM is expected about June
5-7th. If the drift is slower that expected, a small (1/2n) "down"
COTM may be considered for early next week.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | The tuatara, a lizard-like
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | reptile from New Zealand,
|_____|/ |_|/ |_____|/ | has three eyes.
|
| 456.567 | Magellan Update -- 05/30/93 | TINCUP::J_BUTLER | E pur, si muove... | Thu Jun 03 1993 14:26 | 62 |
| Article 3881 of sci.space.news:
Newsgroups: sci.space.news
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From: baalke@kelvin.Jpl.Nasa.Gov (Ron Baalke)
Subject: Magellan Update - 05/30/93
Message-ID: <1JUN199317222209@kelvin.jpl.nasa.gov>
To: sci-space-news@ames.arc.nasa.gov
Followup-To: sci.space
News-Software: VAX/VMS VNEWS 1.41
Keywords: Magellan, JPL
Sender: digester@news.arc.nasa.gov
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Date: Tue, 1 Jun 1993 17:22:00 GMT
Approved: sci-space-news@ames.arc.nasa.gov
Lines: 43
Forwarded from Doug Griffith, Magellan Project Manager
MAGELLAN STATUS REPORT
May 30, 1993
2:30 PM PDT
1. The Transition Experiment continues to successfully maneuver the
Magellan spacecraft toward the desired aerobraking corridor. The
spacecraft has now made 39 atmospheric drag passes and the periapsis
is now at 141 km. All subsystems are reported to be nominal.
2. The main purpose of this aerobraking experiment is to lower the
apoapsis of Magellan's orbit under 700 km. At the start of
aerobraking, apoapsis was at 8460 km. As of today (May 30) it is at
8200 km and will cross the 8000 km distance on June 2nd. The current
prediction is that we will achieve the 700 km apoapsis about August
4th, leaving a nine-day margin in the Transition Experiment.
3. The performance of the spacecraft during the atmospheric drag
passes as well as analysis of orbital changes now indicate an
atmosphere which is 17.5 to 20% above the "Single CO2" VIRA (Venus
International Reference Atmosphere) model.
4. The solar panels continue to increase by 35 degrees C during the
drag pass, reaching a peak of 58 to 60 degrees C. The aerobraking limit
is about 160 degrees. The estimated temperature of the HGA is 94 degrees
C. (with a limit of about 180 degrees)
5. The periapsis altitude will continue to drift downward over the
next week or more, and the first "1/2 up" COTM (Corridor Orbit Trim Maneuver)
is expected about June 5-7th. This will be followed by a series of 1/2 up
COTMs at intervals of 4 to 9 days as the general drift continues downward.
COTM = Corridor Orbit Trim Maneuver
VIRA = Venus International Reference Atmosphere
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | The tuatara, a lizard-like
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | reptile from New Zealand,
|_____|/ |_|/ |_____|/ | has three eyes.
|
| 456.568 | Magellan Update -- 05/31/93 | TINCUP::J_BUTLER | E pur, si muove... | Thu Jun 03 1993 14:28 | 54 |
| Article 3882 of sci.space.news:
Newsgroups: sci.space.news
Path: nntpd2.cxo.dec.com!pa.dec.com!decwrl!ames!dont-send-mail-to-path-lines
From: baalke@kelvin.Jpl.Nasa.Gov (Ron Baalke)
Subject: Magellan Update - 05/31/93
Message-ID: <1JUN199318270928@kelvin.jpl.nasa.gov>
To: sci-space-news@ames.arc.nasa.gov
Followup-To: sci.space
News-Software: VAX/VMS VNEWS 1.41
Keywords: Magellan, JPL
Sender: digester@news.arc.nasa.gov
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Organization: Jet Propulsion Laboratory
Date: Tue, 1 Jun 1993 18:27:00 GMT
Approved: sci-space-news@ames.arc.nasa.gov
Lines: 35
Forwarded from Doug Griffith, Magellan Project Manager
MAGELLAN STATUS REPORT
May 31, 1993
1. The Transition Experiment continues successfully as the Magellan
spacecraft has completed its "walk-in" phase to the desired
aerobraking corridor. The spacecraft has now made 46 atmospheric drag
passes and the periapsis is now under 141 km. All subsystems are
reported to be nominal.
2. The performance of the spacecraft during the atmospheric drag
passes as well as navigation data now indicate an atmosphere which is
17 to 30% above the "Single CO2" VIRA model.
3. The solar panels continue to increase by 35-40 degrees C during
the drag pass, reaching a peak of 62 degrees C. The aerobraking limit is
about 160 degrees. The panel experience higher temperatures during
other portions of the orbit while facing the sun.
4. The periapsis altitude will continue to drift downward at about
0.2 km per day over the next week or more, and the first "1/2 up" COTM
is now planned for early June 4th. This will be followed by a series
of 1/2 up COTMs at intervals of 4 to 9 days as the general drift
continues downward.
COTM = Corridor Orbit Trim Maneuver
VIRA = Venus International Reference Atmosphere
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | The tuatara, a lizard-like
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | reptile from New Zealand,
|_____|/ |_|/ |_____|/ | has three eyes.
|
| 456.569 | Magellan Update -- 06/01/93 | TINCUP::J_BUTLER | E pur, si muove... | Thu Jun 03 1993 14:31 | 64 |
| Article 3886 of sci.space.news:
Newsgroups: sci.space.news
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From: baalke@kelvin.Jpl.Nasa.Gov (Ron Baalke)
Subject: Magellan Update - 06/01/93
Message-ID: <2JUN199300043437@kelvin.jpl.nasa.gov>
To: sci-space-news@ames.arc.nasa.gov
Followup-To: sci.space
News-Software: VAX/VMS VNEWS 1.41
Keywords: Magellan, JPL
Sender: digester@news.arc.nasa.gov
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Date: Wed, 2 Jun 1993 00:04:00 GMT
Approved: sci-space-news@ames.arc.nasa.gov
Lines: 45
Forwarded from Doug Griffith, Magellan Project Manager
MAGELLAN STATUS REPORT
June 1, 1993
1. The Magellan Transition Experiment continues to go extremely well.
The spacecraft has completed its "walk-in" phase to the desired
aerobraking corridor. The spacecraft has made 54 atmospheric drag
passes and the periapsis is now under 140.8 km. All subsystems are
reported to be nominal.
2. The solar panels continue to increase by 35-40 degrees C during
the drag pass, reaching a peak of 62 degrees C.
3. As the spacecraft approaches a drag pass, the attitude control
shifts from reactions wheels to the thrusters and, instead of holding
the position within less than one degree, each axis is given 10
degrees of latitude on either side of the nominal position. Depending
on the residual error as the shift occurs, the spacecraft may turn or
roll to the limits before the thrusters move it back.
4. Then as the aerodynamic forces begin to act on the spacecraft,
these motions in the X and Y axes are damped out. The motions in the
roll axis (Z) often continue, and may go through several cycles back
and forth during the pass.
5. All motions are reduced by the thrusters as control shifts back to
the reaction wheels. The amount of propellant used for attitude
control during the drag pass varies from 0.02 to 0.06 kg.
6. The periapsis altitude will continue to drift downward at about
0.2 km per day over the next week or more, and the first "1/2 up" COTM
is now planned for orbit #7702 at 10:24 AM June 4th. This will be
followed by a series of 1/2 up COTMs at intervals of 4 to 9 days as
the general drift continues downward.
COTM = Corridor Orbit Trim Maneuver
VIRA = Venus International Reference Atmosphere
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | The tuatara, a lizard-like
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | reptile from New Zealand,
|_____|/ |_|/ |_____|/ | has three eyes.
|
| 456.570 | Magellan Update -- 06/02/93 | CXDOCS::J_BUTLER | E pur, si muove... | Sun Jun 06 1993 11:34 | 45 |
| Article: 3897
Newsgroups: sci.space.news
From: baalke@kelvin.Jpl.Nasa.Gov (Ron Baalke)
Subject: Magellan Update - 06/02/93
Sender: digester@news.arc.nasa.gov
Organization: Jet Propulsion Laboratory
Date: Wed, 2 Jun 1993 23:33:00 GMT
Forwarded from Doug Griffith, Magellan Project Manager
MAGELLAN STATUS REPORT
June 2, 1993
1. The Magellan Transition Experiment continues to go extremely well.
The spacecraft has completed its "walk-in" phase to the desired
aerobraking corridor. The spacecraft has made 62 atmospheric drag
passes and the periapsis is now under 140.6 km and the apoapsis has
been reduced below 7900 km. All subsystems are reported to be
nominal.
2. The solar panels continue to increase by 40 degrees C during the
drag pass, reaching a peak of 62 degrees C.
3. Spacecraft controllers are continuing to study the attitude
control during the drag pass. Both the attitude and rate errors are
well within the desired limits, and the average propellant usage is
under the 0.05 kg allocation, but controllers are considering
performing the desat (desaturation of the reaction wheels) shortly
before the drag pass in order to reduce the residual momentum and the
resulting thruster activity.
4. The periapsis altitude will continue to drift downward at about
0.2 km per day for the next few days, and the first "1/2 up" COTM is
now planned for orbit #7702 at 10:24 AM PDT June 4th. This will be
followed by a series of 1/2 up COTMs at intervals of 4 to 9 days as
the general downward drift continues.
COTM = Corridor Orbit Trim Maneuver
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | The tuatara, a lizard-like
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | reptile from New Zealand,
|_____|/ |_|/ |_____|/ | has three eyes.
|
| 456.571 | Poem | VERGA::KLAES | Life, the Universe, and Everything | Sun Jun 06 1993 18:49 | 42 |
| Date: 4 Jun 1993 18:24 UT
From: Ron Baalke <baalke@kelvin.jpl.nasa.gov>
Subject: Magellan Poem
Newsgroups: sci.space
From the "New Yorker", May 31, 1993
By John Updike
MONTES VENERIS
Thanks to Magellan's radar, we
Have maps of Venus and can see,
The "National Geographic" claims,
Whole mountainscapes, complete with names.
Beneath sulfuric acid clouds
That never lift their poison shrouds
Heat like an oven's, turned to CLEAN,
Bakes Theia Mons, sere and serene.
Sif Mons, and Gula Mons, and Maat
And Sapas Mons are where it's at
For altitude, equatorwise.
Up north, on Ishtar Terra, lies
The Lakshmi Planum, right next door
The Maxwell Montes upward soar
And boast a lava peak whose crest
Out-towers our Mt. Everest.
Heights innocent of snow or ice
Or hikers seeking edelweiss,
They rise through hellish murk and are
Subsumed within the evening star.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | The tuatara, a lizard-like
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | reptile from New Zealand,
|_____|/ |_|/ |_____|/ | has three eyes.
|
| 456.572 | Magellan Update -- 06/03/93 | CXDOCS::J_BUTLER | E pur, si muove... | Mon Jun 07 1993 14:55 | 54 |
| Article 3903 of sci.space.news:
Newsgroups: sci.space.news
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From: baalke@kelvin.Jpl.Nasa.Gov (Ron Baalke)
Subject: Magellan Update - 06/03/93
Message-ID: <3JUN199322535459@kelvin.jpl.nasa.gov>
To: sci-space-news@ames.arc.nasa.gov
Followup-To: sci.space
News-Software: VAX/VMS VNEWS 1.41
Keywords: Magellan, JPL
Sender: digester@news.arc.nasa.gov
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Date: Thu, 3 Jun 1993 22:53:00 GMT
Approved: sci-space-news@ames.arc.nasa.gov
Lines: 35
Forwarded from Doug Griffith, Magellan Project Manager
MAGELLAN STATUS REPORT
June 3, 1993
1. The Magellan Transition Experiment continues to go extremely well.
The spacecraft has completed its "walk-in" phase to the desired
aerobraking corridor. The spacecraft has made 70 atmospheric drag
passes and the periapsis is now under 140.4 km and the apoapsis has
been reduced below 7800 km. All subsystems are reported to be
nominal.
2. The solar panels continue to increase by 40-45 degrees C during
the drag pass, reaching a peak of 64 degrees C.
3. Spacecraft controllers are considering performing the desat
(desaturation of the reaction wheels) shortly before the drag pass in
order to reduce the residual momentum and the resulting thruster activity.
This may reduce the propellant usage during the drag pass, even though
the present usage is under the allocated amount.
4. The periapsis altitude will be raised about 800 meters by the
first "1/2 up" COTM now planned for orbit #7702 at 10:20 AM
tomorrow. However, it will continue its downward drift and require a
series of 1/2 up COTMs at intervals of 4 to 9 days as the general
downward drift continues.
COTM = Corridor Orbit Trim Maneuver
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | The tuatara, a lizard-like
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | reptile from New Zealand,
|_____|/ |_|/ |_____|/ | has three eyes.
|
| 456.573 | Magellan Update -- 06/04/93 | CXDOCS::J_BUTLER | E pur, si muove... | Wed Jun 09 1993 15:16 | 48 |
| Article 3911 of sci.space.news:
Newsgroups: sci.space.news
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From: baalke@kelvin.Jpl.Nasa.Gov (Ron Baalke)
Subject: Magellan Update - 06/04/93
Message-ID: <4JUN199322592282@kelvin.jpl.nasa.gov>
To: sci-space-news@ames.arc.nasa.gov
Followup-To: sci.space
News-Software: VAX/VMS VNEWS 1.41
Keywords: Magellan, JPL
Sender: digester@news.arc.nasa.gov
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Date: Fri, 4 Jun 1993 22:59:00 GMT
Approved: sci-space-news@ames.arc.nasa.gov
Lines: 29
Forwarded from Doug Griffith, Magellan Project Manager
MAGELLAN STATUS REPORT
June 4, 1993
1. The Magellan Transition Experiment continues to go extremely well.
The spacecraft has made 78 atmospheric drag passes and the periapsis
is now at 141.1 km following COTM4 this morning. The apoapsis has
been reduced below 7700 km. All subsystems are reported to be
nominal.
2. The solar panels continue to increase by 40-45 degrees C during
the drag pass, reaching a peak of 64 degrees C.
3. The periapsis altitude will continue its downward drift and
require a series of 1/2 up COTMs at approximately weekly intervals for
the next 6 or 7 weeks of aerobraking.
4. The total aerobraking period is estimated to be 71 days with about
16 COTMs, either up or down to maintain the proposed corridor.
COTM = Corridor Orbit Trim Maneuver
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | The tuatara, a lizard-like
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | reptile from New Zealand,
|_____|/ |_|/ |_____|/ | has three eyes.
|
| 456.574 | Magellan Update -- 06/07/93 | CXDOCS::J_BUTLER | E pur, si muove... | Thu Jun 10 1993 14:38 | 59 |
| Article 3929 of sci.space.news:
Newsgroups: sci.space.news
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From: baalke@kelvin.Jpl.Nasa.Gov (Ron Baalke)
Subject: Magellan Update - 06/07/93
Message-ID: <7JUN199322574955@kelvin.jpl.nasa.gov>
To: sci-space-news@ames.arc.nasa.gov
Followup-To: sci.space
News-Software: VAX/VMS VNEWS 1.41
Keywords: Magellan, JPL
Sender: digester@news.arc.nasa.gov
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Date: Mon, 7 Jun 1993 22:57:00 GMT
Approved: sci-space-news@ames.arc.nasa.gov
Lines: 40
Forwarded from Doug Griffith, Magellan Project Manager
MAGELLAN STATUS REPORT
June 7, 1993
1. The Magellan Transition Experiment continues to go well. As of
11:30 this morning the spacecraft had made 100 atmospheric drag passes
and the apoapsis has been reduced below 7430 km. All subsystems are
nominal.
2. The orbit period is now under 3 hours, and shrinks by 10-12
seconds on every orbit. This changing period requires frequent
updates to the on-board timing reference files, so that spacecraft
commands are executed at the proper time in the orbit.
3. The solar panels continue to increase by 40-45 degrees C during
the drag pass, reaching a peak of 64 degrees C, but this about 20 deg
less than the predicted heating from atmospheric friction. The
estimated max temperature of the High Gain Antenna is 102 degrees C.
4. Spacecraft controllers have deferred plans to perform the desat
(desaturation of the reaction wheels) shortly before the drag pass in
order to reduce the residual momentum and the resulting propellant usage.
The present error in the spin rate of the reaction wheels is below the
threshold level for a desat.
5. COTM5, the next periapsis raise maneuver is now scheduled for
orbit #7762 at 8:06 PM PDT next Friday evening. It will be another
"1/2 up" COTM. The periapsis will continue its downward drift and
require a series of 1/2 up COTMs at intervals of 4 to 9 days over the
next several weeks.
COTM = Corridor Orbit Trim Maneuver
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | The tuatara, a lizard-like
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | reptile from New Zealand,
|_____|/ |_|/ |_____|/ | has three eyes.
|
| 456.575 | Magellan Update -- 06/14/93 | TINCUP::J_BUTLER | E pur, si muove... | Tue Jun 15 1993 14:26 | 51 |
| Article 3987 of sci.space.news:
Newsgroups: sci.space.news
Path: nntpd2.cxo.dec.com!pa.dec.com!decwrl!ames!dont-send-mail-to-path-lines
From: baalke@kelvin.Jpl.Nasa.Gov (Ron Baalke)
Subject: Magellan Update - 06/14/93
Message-ID: <14JUN199323545498@kelvin.jpl.nasa.gov>
To: sci-space-news@ames.arc.nasa.gov
Followup-To: sci.space
Forwarded from Doug Griffith, Magellan Project Manager
MAGELLAN STATUS REPORT
June 14, 1993
1. The Magellan Transition Experiment continues to go exceptionally
well. As of midday the spacecraft had made 158 atmospheric drag
passes and the apoapsis has been reduced below 6600 km. All
subsystems are nominal.
2. The orbit period is now under two hours, 48 minutes and shrinks
by 10-12 seconds on every orbit.
3. The solar panels continue to increase by 45-48 degrees C during
the drag pass, reaching a peak of 76.5 degrees C, but the limit is 160
degrees. The estimated maximum temperature of the High Gain Antenna
is 120 degrees C against a limit of 180 degrees.
4. Late last week spacecraft controllers reduced the drag pass
timing in order to shorten the period during which the thrusters are
used to maintain attitude control. This has dramatically reduced the
propellant usage. It now averages 0.015 kg/orbit, compared with 0.04
prior to the change.
5. COTM5, the next periapsis raise maneuver, has now been scheduled
for orbit #7800 early Wednesday. Even with the delay, the dynamic
pressure is not expected to reach the new "trigger point" at 0.35
N/m2.
6. Mission Planning Team has not yet recalculated the aerobraking
duration, based on the new 0.35 N corridor, but estimates the present
margin at 15 days, completing the experiment by July 30.
COTM = Corridor Orbit Trim Maneuver
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | The tuatara, a lizard-like
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | reptile from New Zealand,
|_____|/ |_|/ |_____|/ | has three eyes.
|
| 456.576 | Magellan Update -- 06/21/93 | CXDOCS::J_BUTLER | E pur, si muove... | Wed Jun 23 1993 19:36 | 52 |
|
Forwarded from Doug Griffith, Magellan Project Manager
MAGELLAN STATUS REPORT
June 21, 1993
1. With 27 days elapsed in the 80-day Transition Experiment, the
Magellan mission still has a margin of 15 days in the estimated
completion of aerobraking.
2. The spacecraft has made 220 drag passes in the upper atmosphere,
and the apoapsis has been reduced by over 2700 km. The apoapsis will
be reduced by almost 8000 km by the end of the Transition Experiment.
All subsystems are nominal.
3. Corridor Orbit Trim Maneuver #6 was executed early Sunday morning,
raising the periapsis by about 700 m. COTM7 is expected by Wednesday
or Thursday of this week.
4. The move of COTM6 by four days from its original predicted time
illustrates the uncertainty of these aerobraking operations. COTM
predictions are based on our best models of the atmosphere, local
gravity fields, and the effects of small forces. As the spacecraft
controllers compare the actual performance with the predictions,
adjustments are made to the plan.
5. The atmospheric model includes the effect of local solar time,
that is, the angle of the sun where Magellan makes its drag pass.
Currently, the local solar time is nearing 1:30 PM and will pass to
the night side of Venus before aerobraking is completed. There is
greater uncertainty about the nightside atmosphere.
6. The local gravity field seems to match closely the R50x50S
Magellan gravity field model rather than an earlier gravity model
which had been used for planning the aerobraking experiment.
7. The "small forces" are primarily the thruster firings used to
maintain attitude control during the drag pass. Although these forces
are measured in millimeters/sec relative to Magellan's velocity in orbit,
they have to be considered when predicting the spacecraft's orbit several
days in the future.
8. The continuous refinement in our predictions is helping the
spacecraft team maintain a "safe" corridor for Magellan's aerobraking
experiment.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Don't outlive your money.
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 |
|_____|/ |_|/ |_____|/ |
|
| 456.577 | Magellan Update -- 06/28/93 | CXDOCS::J_BUTLER | E pur, si muove... | Mon Jun 28 1993 21:43 | 49 |
|
Forwarded from:
PUBLIC INFORMATION OFFICE
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIF. 91109. TELEPHONE (818) 354-5011
MAGELLAN STATUS REPORT
June 28, 1993
The Magellan Transition Experiment to circularize the
spacecraft's orbit by lowering it into the top of the Venusian
atmosphere to create drag is going very well, project officials
said today.
As of last Friday, June 25, the spacecraft had made 260
atmospheric drag passes and the apoapsis, or furthest point from
the planet, had been lowered below 5,300 kilometers (3,286 miles)
from its original orbital apoapsis of 8,540 kilometers (5,294
miles).
The spacecraft's closest point to the planet, or periapsis,
is being maintained at between 138 and 140 kilometers altitude
(about 86 to 88 miles).
The spacecraft also is being maintained in a specific
corridor on its closest passes to the planet. Plans were being
made to execute a corridor orbit trim maneuver, or COTM, Thursday
to slightly raise the altitude at periapsis and maintain a steady
course during the upcoming July 4th holiday weekend.
It is expected the orbit will be sufficiently changed by
early August so that only fine-tuning the orbit will be needed to
achieve the desired, nearly circular orbit required for high-
resolution gravity studies of Venus.
This is the first time a spacecraft's orbit has been changed
at another planet by "aerobraking", or using the planet's
atmosphere to create drag.
_____
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Don't outlive your money.
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 |
|_____|/ |_|/ |_____|/ |
|
| 456.578 | Book: "The Evening Star: Venus Observed" | CXDOCS::J_BUTLER | E pur, si muove... | Mon Jun 28 1993 21:44 | 47 |
|
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Subject: New Magellan Book
Henry Cooper's book about Magellan has been published. It should
now, or very soon, be in book stores near you. (If you doubt
whether your local store will get it, it can usually be ordered.
Your local library might also benefit from getting a copy.)
The bibliographic details are:
Author: Henry S.F. Cooper
Title: The Evening Star: Venus Observed
Publisher: Farrar, Straus, Giroux
ISBN: 0-374-15000-1
To quote from the dust jacket:
"In "The Evening Star", Henry S.F. Cooper, Jr., veteran
science and space reporter for "The New Yorker", tracks the
Magellan spacecraft that has been mapping Venus from orbit since
August, 1990. In eloquent, vivid prose, Cooper introduces us to
the engineers who have nursed the spacecraft's fragile
electronics and the scientists who have used the spacecraft's
data to assemble a picture of this strange new world.
..
With a keen eye for irony and a knack for making the most
sophisticated technology eminently accessible, Cooper highlights
the continued importance of NASA space missions and the tenuous
politics of their administration. An evocative narrative of the
people who do science and of the challenges that confront them,
"The Evening Star" is an illuminating portrait not only of
Venus's character but of Earth's as well, and of the place of the
two siblings in the family of planets.
Henry S.F. Cooper, Jr., has been a staff writer for "The New
Yorker" for over twenty-five years. He is the author of
"Thirteen: The Flight That Failed", "A House in Space", and "The
Search for Life on Mars". He lives in New York City."
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Don't outlive your money.
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 |
|_____|/ |_|/ |_____|/ |
|
| 456.579 | Magellan Update -- 06/28/93 | CXDOCS::J_BUTLER | E pur, si muove... | Fri Jul 02 1993 14:25 | 36 |
|
Forwarded from Doug Griffith, Magellan Project Manager
MAGELLAN STATUS REPORT
June 28, 1993
1. With 34 days elapsed in the 80-day Transition Experiment,
aerobraking continues to go extremely well.
2. The spacecraft has made 289 drag passes in the upper atmosphere,
and the apoapsis has been reduced by over 3500 km. The apoapsis will
be reduced by almost 8000 km by the end of the Transition Experiment.
All subsystems are nominal.
3. The periapsis continues to drift downward, requiring periodic up
maneuvers to maintain the desired position in the aerobraking
corridor. Corridor Orbit Trim Maneuver #9 will be executed Wednesday
or Thursday and will be a full up maneuver in order to maintain the
corridor through the Independence Day weekend.
4. The downward drift is primarily an effect of the local gravity
field. In mid-July this will reverse, and the trend will be upward.
The present margin in the schedule may allow spacecraft controllers to
ride the trend out to the end of July with no down maneuvers.
5. The solar panels reach a peak temperature of 82 degrees C during
the drag pass, which translates to a High Gain Antenna temperature
peak of 124 degrees C. Both of these peaks are well below the
aerobraking limits.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Don't outlive your money.
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 |
|_____|/ |_|/ |_____|/ |
|
| 456.580 | Magellan Update -- 06/30/93 | CXDOCS::J_BUTLER | E pur, si muove... | Fri Jul 02 1993 14:26 | 47 |
|
Forwarded from Doug Griffith, Magellan Project Manager
MAGELLAN STATUS REPORT
June 30, 1993
1. The Magellan Transition Experiment continues to go well after 309
orbits of dragging through Venus' atmosphere.
2. Over the past 24 hours the atmospheric density has increased more
rapidly than expected, so the Orbit Trim Maneuver (OTM) planned for
tomorrow afternoon has been rescheduled for 5:07 PM PDT today.
3. The spacecraft's looping command sequence is designed to include
an OTM on any even-numbered orbit, and pre-set parameters are on-board
for eight variations of the maneuver, so the spacecraft controllers
can enable an "unplanned OTM" within a few hours.
4. Based on doppler tracking data, the Navigation Team calculated the
dynamic pressure for a series of orbits to be over 0.36 N/m2. Even
the 11-orbit average reached the trigger point of 0.35 N/m2.
5. This increase in the atmosphere was also evident in the
temperatures on the solar panels which peaked near 87 degrees C. This
translates to a High Gain Antenna temperature peak of 130 degrees C.
6. The Navigation Team had noticed a similar rise in the atmospheric
density at the same local solar time during Cycle-4. The reason for
the atmospheric "blooming" is not well-understood, but it could
continue for several weeks.
7. Since today's OTM will be a "full up" maneuver, mission planners
still expect COTM10 to occur on July 8. It will also have the effect
of stretching out the aerobraking period so that the orbital period
does not shrink below 102 minutes by July 27.
8. July 27th is the day Magellan will switch to a new pair of stars
for attitude control. The new star pair takes into account the
changing orbit period and geometry as the mission goes into circular
orbit operations.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Don't outlive your money.
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 |
|_____|/ |_|/ |_____|/ |
|
| 456.581 | Magellan Update -- 07/06/93 | CXDOCS::J_BUTLER | E pur, si muove... | Wed Jul 07 1993 12:44 | 49 |
| Forwarded from:
PUBLIC INFORMATION OFFICE
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIF. 91109. TELEPHONE (818) 354-5011
MAGELLAN STATUS REPORT
July 6, 1993
The Magellan spacecraft continues successfully to
circularize its orbit around Venus. The Transition Experiment to
lower the orbit by dragging it through the top of the Venusian
atmosphere has gone well since its first "drag pass" May 25,
project officials said.
As of today, July 6, the apoapsis, or furthest point in the
elliptical orbit, has been reduced from 8,460 to 3,850 kilometers
(5,245 to 2,387 miles).
The periapsis, or lowest point in the orbit, has gone from
180 to 137 kilometers (112 to 85 miles). The last trim maneuver
was June 30. The next maneuver is scheduled for July 14.
By the end of the experiment in early August, the
spacecraft's orbit will be between 500 and 700 kilometers (310 to
434 miles) at apoapsis and between 134 and 200 kilometers (83 to
124 miles) at periapsis.
The spacecraft also has gone from 7.3 orbits per day to 11.2
orbits and by the end of the experiment will be making 15 orbits
of the planet each Earth day.
Magellan has been performing gravity mapping studies and the
new orbit will permit higher resolution mapping at the poles and
the higher and lower latitudes.
This is the first time a spacecraft's orbit has been changed
at another planet by "aerobraking", or using the planet's
atmosphere to create drag.
_____
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | There is no such thing as
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | a "temporary" tax increase.
|_____|/ |_|/ |_____|/ |
|
| 456.582 | Magellan Atlas Program | CXDOCS::J_BUTLER | E pur, si muove... | Fri Jul 09 1993 15:20 | 64 |
|
==========================
MAGELLAN ATLAS PROGRAM
July 8, 1993
===========================
An updated version of the Magellan Atlas program has been released by
the Magellan project. This program was designed to be used with the Magellan
CDROMs and runs on IBM PC computers. This program will do the following:
o Find the CD-ROMs and mosaics which cover a specified
latitude/longitude on Venus;
o Find the latitude/longitude of named features on Venus, as
well as a short description of the origin of the name (that
is, for whom the feature is named);
o Find the named features contained in (or lying on) a
specific mosaic. (This should help those who have only one
or a small number of CD-ROMs and wish to learn which
features they show.)
o Find named feature contained in (or lying on) a specified
region in latitude/longitude. (This should help identify
features whose names are not known, but whose approximate
latitude/longitude are.)
This updated version of the program covers the Magellan CD-ROMs
1-80. A corresponding Macintosh program will also be available soon.
The program has been compressed with PKZIP into the file
MAGELLAN.ZIP. In order to de-compress it, copy both files on the
disk into a subdirectory on your hard disk. Move to that
subdirectory and type "PKUNZIP MAGELLAN". After de-compressing
the files, the two original files (MAGELLAN.ZIP and PKUNZIP.EXE)
can be erased to save space. In order to run the program, move to
the subdirectory in which you have placed it and type "MAGELLAN".
The Magellan Atlas program is available using anonymous ftp to:
ftp: ames.arc.nasa.gov (128.102.18.3)
user: anonymous
cd: pub/SPACE/SOFTWARE
files: magellan.zip (IBM PC version -> PKZIP)
For those who wish to work in more detail with this data, the
database files used in this program are also available. A description
of each field is included at the beginning of each file. The database
files are available at:
ftp: ames.arc.nasa.gov (128.102.18.3)
user: anonymous
cd: pub/SPACE/MAGELLAN
files: names.txt (ASCII)
midr.txt (ASCII)
mgn-dbf.zip (2 DBase files -> PKZIP)
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | There is no such thing as
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | a "temporary" tax increase.
|_____|/ |_|/ |_____|/ |
|
| 456.583 | Magellan Update -- 07/09/93 | CXDOCS::J_BUTLER | E pur, si muove... | Fri Jul 09 1993 19:30 | 43 |
|
Forwarded from Doug Griffith, Magellan Project Manager
MAGELLAN STATUS REPORT
July 9, 1993
1. The Magellan Transition Experiment continues to go well after 390
orbits of aerobraking in the Venus atmosphere. All subsystems are
reported to be nominal. The apoapsis has been reduced below 3600 km
(from its original 8460 km).
2. Atmospheric density has decreased since COTM9 a week ago which has
resulted in dynamic pressure staying below 0.30 N/m2. Prior to COTM9,
the spacecraft had been routinely operated at dynamic pressures in the
0.30 to 0.35 N/m2 range.
3. It is now predicted that Magellan will achieve an orbital period
of 103 minutes by July 27 without any further COTMs. However, if the
atmosphere continues to "drop away," some down maneuvers may be
considered to assure an orbital period close to 102 minutes on that
date.
4. Magellan missed a series of starcals (star calibrations) late in
the week due to a high angular change from earthpoint to the start of
the starcal sweep, but this has been corrected.
Magellan Significant Events for Next Week
1. The periapsis altitude will continue to drift downward until
mid-July, then upward. No further COTMs are expected.
2. The "end game" phase of aerobraking is now targeted for the period
between July 27 and August 8 with a final orbit 200 km and 600 km from
the surface of Venus. Exact altitude values are still being refined.
COTM = Corridor Orbit Trim Maneuver
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | There is no such thing as
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | a "temporary" tax increase.
|_____|/ |_|/ |_____|/ |
|
| 456.584 | Magellan Update -- 07/12/93 | CXDOCS::J_BUTLER | E pur, si muove... | Wed Jul 14 1993 21:11 | 42 |
|
Forwarded from Doug Griffith, Magellan Project Manager
MAGELLAN STATUS REPORT
July 12, 1993
1. The Magellan Transition Experiment continues to go well after 48
days and 440 orbits of aerobraking in Venus' atmosphere. The apoapsis
has been reduced below 3200 km from a starting point of 8460 km.
2. The orbit period has been reduced from 194 minutes to 124 minutes,
so we now perform 11.5 orbits per day.
3. This week Magellan is passing through a phase in which the local
gravity field changes, causing the periapsis drift to reverse from the
downward trend we have seen since the start of aerobraking to an
upward drift.
4. It now appears that we will perform a "1/2 down" COTM10 on
Thursday morning in order to keep the orbit change on course for
achieving a 102 minutes orbit by July 27th.
5. On that date we begin the End Game which will place Magellan in
the desired orbit for collecting gravity data in the high latitude
regions of Venus. The End Game adjustments are designed to achieve an
orbit which varies form 200 to 650 km from the planet's surface, with
a period of 94 minutes.
6. All spacecraft systems are nominal. The solar panels still peak
about 70 degrees C which translates to a High Grain Antenna maximum of
105 degrees C. Propellant usage is now running between 10 and 20
grams per orbit, and there is currently a 17 kg margin (enough
propellant to maintain Magellan through several Venus cycles).
COTM = Corridor Orbit Trim Maneuver
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | There is no such thing as
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | a "temporary" tax increase.
|_____|/ |_|/ |_____|/ |
|
| 456.585 | Magellan Update -- 07/14/93 | CXDOCS::J_BUTLER | E pur, si muove... | Fri Jul 16 1993 13:42 | 53 |
|
Forwarded from:
PUBLIC INFORMATION OFFICE
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIF. 91109. TELEPHONE (818) 354-5011
MAGELLAN STATUS REPORT
July 14, 1993
The Magellan spacecraft, after more than 450 orbits of
aerobraking, continues successfully to circularize its orbit
around Venus. The Transition Experiment to lower the orbit by
dragging it through the top of the Venusian atmosphere began May
25.
As of today, July 14, the apoapsis, or furthest point in the
elliptical orbit, has been reduced from 8,460 to below 3,200
kilometers (5,245 to 1,904 miles).
The orbit period has been reduced from 194 minutes to 124
minutes. There are now 11.5 orbits per day.
This week, Magellan is passing through a phase in which the
local gravity field changes. That has caused the spacecraft, at
its closest point to the planet, to drift upward instead of
toward the planet.
Project officials said they planned to perform a maneuver
Thursday (July 15) to keep the orbit change on course for
achieving a 102-minute orbit by July 27.
At the time, the "end game" will begin to place Magellan in
the desired orbit for collecting gravity data in the higher
latitudes of Venus. The fine tuning adjustments of the end game
are designed to achieve an orbit which varies from 200 to 650
kilometers (124 to 403 miles) from the surface with an orbital
period of 94 minutes.
All spacecraft systems remained normal with temperatures
well within expected ranges. Propellant usage was running between
10 and 20 grams per orbit, and there was a 17-kilogram (37.5
pounds) margin -- enough thruster propellant to maintain Magellan
through several Venus cycles.
_____
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | There is no such thing as
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | a "temporary" tax increase.
|_____|/ |_|/ |_____|/ |
|
| 456.586 | Magellan Update -- 07/16/93 | CXDOCS::J_BUTLER | E pur, si muove... | Fri Jul 16 1993 22:35 | 34 |
|
Forwarded from Doug Griffith, Magellan Project Manager
MAGELLAN STATUS REPORT
July 16, 1993
1. The Magellan Transition Experiment continues to go well after 52
days of aerobraking in the Venus atmosphere. All subsystems are
reported to be nominal. The apoapsis has been reduced below 2700 km
(from its original 8460 km).
2. Atmospheric density has continued to decrease since COTM9 two
weeks ago, so COTM10, a 1/2 down maneuver, was performed early
Thursday to keep the orbit change on track for achieving a 102-minute
orbit on July 27th.
Magellan Significant Events for Next Week
1. The periapsis altitude will drift upward until late July, then
downward. Another full down COTM is planned for Tuesday.
2. The "end game" phase of aerobraking is now targeted for the period
between July 27 and August 8, with a final orbit 200 km and 650 km
from the surface of Venus.
COTM = Corridor Orbit Trim Maneuver
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Common sense is not very
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | common.
|_____|/ |_|/ |_____|/ |
|
| 456.587 | Magellan Update -- 07/28/93 | CXDOCS::J_BUTLER | E pur, si muove... | Fri Jul 30 1993 14:17 | 19 |
|
MAGELLAN STATUS REPORT
July 28, 1993
On July 27, 1993 at 1941Z, DSS-42 (Canberra 34 meter antenna) was
unable to achieve receiver lock from the HGA (High Gain Antenna) of the
Magellan spacecraft. The project reported the HGA was off Earth point.
Using DSS-63 (Madrid 70 meter antenna), the project commanded several
attitude adjustments via the MGA (Medium Gain Antenna) and were able to
lock up on the data from the HGA on July 28, 1993 at 1043Z. The project
requested additional DSS-63 support from the Pioneer 10 project which
Ames Research Center agreed to.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Common sense is not very
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | common.
|_____|/ |_|/ |_____|/ |
|
| 456.588 | Magellan Update -- 08/02/93 | CXDOCS::J_BUTLER | E pur, si muove... | Tue Aug 03 1993 03:13 | 29 |
|
Forwarded from Doug Griffith, Magellan Project Manager
MAGELLAN STATUS REPORT
August 2, 1993
1. Aerobraking continues to go extremely well. The apoapsis has been now
reduced to below 600 km and the orbit period to 95 minutes. We now perform
15 orbits per day. Atmospheric drag is reducing the apoapsis by about 10 km
per orbit.
2. EOTM #1 (Exit Orbit Trim Maneuver #1), the first of 5 EOTM's to raise
Magellan's periapsis, is scheduled for early tomorrow morning. This will raise
the spacecraft out of the outer atmosphere and end the aerobraking. EOTM #1
will occur at 4:40 AM PDT on orbit 8355. At that time the apoapsis will be
about 523 km from the surface, and the periapsis will be at 134.8 km.
EOTM #2 will follow on the next orbit to further raise the periapsis to 160 km.
3. Up to three more EOTM's will be performed in the next few days to put
Magellan in the final near cicurlar orbit for high latitude gravity data
acquisition. The final orbit is expected to be 200 x 525 km measured
from Venus' surface.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | When given a choice between
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | two exciting things, choose
|_____|/ |_|/ |_____|/ | the one you haven't tried.
|
| 456.589 | Magellan Update -- 08/03/93 ...Aerobraking ended; periapsis now out of the atmosphere | SKYLAB::FISHER | Carp Diem : Fish the Day | Tue Aug 03 1993 18:43 | 33 |
|
Forwarded from Doug Griffith, Magellan Project Manager
MAGELLAN STATUS REPORT
August 3, 1993
1. The EOTM #1 (Exit Orbit Trim Maneuver #1), the first of five EOTM's to
raise Magellan's periapsis, was performed at 4:40 AM PDT this morning. This
raised the spacecraft by 14 km out the upper atmosphere and ended aerobraking.
At the end of aerobraking, the apoapsis had been reduced to about 540 km
from a starting distance of 8470 km, and the orbit period shortened by 100
minutes.
2. EOTM #2 was performed on the following orbit to further raise the
periapsis to 160 km. Up the three more EOTM's will be performed on Thursday
to put Magellan in a near cicurlar final orbit for high latitude gravity data
acquisition. The final orbit is expected to be 200 x 540 km measured from
Venus' surface.
3. The Magellan Transition Experiment demonstrates a significent new maneuver
technology by achieving a major orbit change with minimal propellant and
enabling new scientific observations near the poles of Venus. It represents
an impressive effort by the Magellan flight team to adapt the attitude control,
thermal constraints and limited telemetry capability of an aging spacecraft to
the unforseen challenge of aerodynamic flight in a highly variable upper
atmosphere of another planet. It has been successfully accomplished, and we
congratulate them.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | When given a choice between
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | two exciting things, choose
|_____|/ |_|/ |_____|/ | the one you haven't tried.
|
| 456.590 | Magellan Update -- 08/05/93 | TINCUP::J_BUTLER | E pur, si muove... | Tue Aug 10 1993 13:41 | 37 |
| Forwarded from Doug Griffith, Magellan Project Manager
MAGELLAN STATUS REPORT
August 5, 1993
1. EOTMs 3, 4 and 5 (Exit Orbit Trim Maneuvers) to further raise Magellan's
periapsis will be performed today on three consecutive orbits beginning at
about 11AM PDT. Each EOTM will raise the periapsis by 14 km with a final
level at 205 km.
2. All spacecraft subsystems are nominal. The solar panels shows no effects
from the 70 days of exposure to the harsh environment of drag passes.
3. The Magellan Transition Experiment demonstrates a significent new maneuver
technology by achieving a major orbit change with minimal propellant and
enabling new scientific observations near the poles of Venus.
4. Circular orbit operations will begin August 16th with a command sequence
with emphasizes data gravity acquisition near the poles of Venus. Although
the final orbit following the EOTMs is relatively stable, it will change in
response to local gravity and atmospheric variations. Over the 14 months
proposed for the Lean Mean Gravity Team extended mission, the perapsis will
drift from 200 down to 155 km and back up to 194 km. The orbit period will
vary by as much as 20 seconds. This orbit will extend the excellent gravity
data collected by Magellan near Venus' equatorial lattitudes to the whole
globe.
5. As of next Tuesday, August 10, the 3rd anniversary of Magellan's arrival
at Venus, the spacecraft will have orbited 8350 times and travelled almost
550 million kilometers around the planet.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | When given a choice between
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | two exciting things, choose
|_____|/ |_|/ |_____|/ | the one you haven't tried.
|
| 456.591 | Magellan Update -- 08/06/93 | TINCUP::J_BUTLER | E pur, si muove... | Tue Aug 10 1993 13:42 | 36 |
|
Forwarded from Doug Griffith, Magellan Project Manager
MAGELLAN STATUS REPORT
August 6, 1993
1. Aerobraking the Magellan spacecraft into a near circular orbit on
Venus was successfully completed on Tuesday, 8/3/93. The apoapsis was
reduced from 8460 to 540 km, and the orbit period to 94 minutes.
2. Magellan's periapsis was lifted out of the upper atmosphere by a
series of five Exit OTMs (Orbit Trim Maneuvers) which began early Tuesday
and finished on Thursday. The final orbit is 540 x 197 km.
3. The Magellan Transition Experiment demonstrates a significant new
maneuver technology by achieving a major orbit change with minimal
propellant and enabling new scientific observations near the poles of
Venus.
Magellan Significant Events for Next Week
1. A press conference on Magellan's successful aerobraking will be
held at JPL on Tuesday, August 10 at 10:00 A.M., and broadcast on
NASA-Select.
2. Tuesday also marks the 3rd anniversary of MagellanUs arrival at
Venus.
3. Circular orbit operations will officially begin on August 16th.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | When given a choice between
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | two exciting things, choose
|_____|/ |_|/ |_____|/ | the one you haven't tried.
|
| 456.592 | Aerobraking a success | VERGA::KLAES | Quo vadimus? | Thu Aug 12 1993 20:55 | 102 |
| From: US1RMC::"baalke@kelvin.Jpl.Nasa.Gov" "Ron Baalke" 10-AUG-1993
To: sci-space-news@uunet.uu.net
CC:
Subj: Magellan Aerobraking at Venus a Success
Paula Cleggett-Haleim
Headquarters, Washington, D.C.
August 10, 1993
(Phone: 202/358-0883)
Jim Doyle
Jet Propulsion Laboratory, Pasadena, Calif.
(Phone: 818/354-5011)
RELEASE: 93-144
MAGELLAN AEROBRAKING AT VENUS A SUCCESS
Magellan Project officials at NASA's Jet Propulsion Laboratory,
Pasadena, Calif., today announced the successful first-of-a-kind experiment
to "aerobrake" a spacecraft by dipping it into the atmosphere of a planet.
The Magellan spacecraft's orbit was changed from highly elliptical to
nearly circular by dragging it through the top of the thick Venusian
atmosphere repeatedly over a period of 70 days, ending on Aug. 3, 1993.
Magellan was the first orbiting planetary spacecraft to use atmospheric
drag, or aerobraking, to change its orbit. Launched in May 1989, Magellan was
placed in an orbit with a closest approach, or periapsis, of 186 miles (300
kilometers), on Aug. 10, 1990. Its furthest distance from the planet, or
apoapsis, was 5,270 miles (8,500 kilometers).
Starting on May 25, 1993, with carefully controlled rocket firings,
project engineers were able to lower the periapsis to about 87 miles (140
kilometers) which is just skimming the thin upper atmosphere.
The purpose was to reduce the orbital high point, apoapsis, using the
atmospheric drag to slow the spacecraft rather than the limited fuel
available for the small rocket thrusters, which was not enough for the desired
change.
Magellan's orbit was successfully modified from a 3-hour, 15-minute
elliptical orbit to a nearly circular 94-minute orbit, about the same as
orbital periods of Space Shuttle flights around Earth.
Additionally, the project was able to gather significant new information
about the planet's atmosphere.
In its new orbit, Magellan is positioned to profile the planet's gravity
at the mid and higher latitudes and the poles to give scientists a better
picture of Venus' interior.
"A historic first for planetary spacecraft has been achieved by
demonstrating the innovative aerobraking technique to change orbits," said
Project Manager Doug Griffith. "The Magellan flight team has done this on a
shoestring budget in the best spirit of cheaper-better-faster."
Project Scientist Steve Saunders said that with the circular orbit, "We
will begin collecting valuable gravity data around the poles for the first
time."
By mapping key areas at the higher latitudes, he said, scientists will be
able to compare gravity anomalies of surface features to understand how those
features are caused by interior processes.
"We will see global patterns that will help us understand the origin of
major surface features such as mountains and plateaus," he said.
Aerobraking in the atmosphere of Venus also provided a better
understanding of planetary atmospheric response to the 11-year sun spot cycle,
said Dr. Gerald Keating, Senior Research Scientist from NASA's Langley
Research Center, Hampton, Va.
"We are learning from Venus about greenhouse heating near the surface and
exceptionally strong cooling of the upper atmosphere, processes which may
affect Earth in the future," Keating said.
During the aerobraking, he said, it was found that aerodynamic heating
of the spacecraft was much less than expected. The Venus atmosphere also was
less disturbed than expected.
"These findings indicate that future spacecraft may be able to safely fly
lower in carbon dioxide atmospheres than previously believed, making
aerobraking a more effective technique and thus, improving the designs of
future Mars and Venus missions," Keating said.
Magellan finished its radar mapping of the surface of Venus on Sept.
14, 1992, returning images of 98 percent of the planet. It subsequently
mapped the gravity of Venus with high resolution in the equatorial band for a
full cycle, which is 1 Venus day or 243 Earth days.
The aerobraking experiment began on May 25. High resolution gravity
mapping of the mid and high latitude regions and the poles will begin Aug. 16
from the near-circular orbit.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | When given a choice between
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | two exciting things, choose
|_____|/ |_|/ |_____|/ | the one you haven't tried.
|
| 456.593 | Magellan Update -- 08/13/93 | TINCUP::J_BUTLER | E pur, si muove... | Mon Aug 16 1993 14:01 | 30 |
|
Forwarded from Doug Griffith, Magellan Project Manager
MAGELLAN STATUS REPORT
August 13, 1993
1. A press conference on Magellan's successful aerobraking was held
at JPL on Tuesday, August 10 at 10:00 A.M. and broadcast on
NASA-Select. The presenters were Doug Griffith, Ann Tavormina, Gerry
Keating and Steve Saunders.
2. The Magellan aerobraking experiment demonstrated a significant new
maneuver technology by achieving a major orbit change with minimal
propellant and enabling new scientific observations near the poles of
Venus.
3. Tuesday the Project marked the third anniversary of Magellan's
arrival at Venus with an evening party attended by about 90 present
and former team members, science investigators and friends.
Magellan Significant Events for Next Week
1. Circular orbit operations will officially begin on August 16th.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | When given a choice between
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | two exciting things, choose
|_____|/ |_|/ |_____|/ | the one you haven't tried.
|
| 456.594 | Earth to help MAGELLAN radar map Venus | VERGA::KLAES | Quo vadimus? | Tue Aug 17 1993 12:49 | 45 |
| From: US1RMC::"baalke@kelvin.Jpl.Nasa.Gov" "Ron Baalke" 17-AUG-1993
To: sci-space-news@uunet.uu.net
CC:
Subj: Magellan May Conduct Bistatic Radar Experiment
Aviation Week & Space Technology
August 16, 1993
Magellan May Conduct Bistatic Experiment
Magellan scientists may attempt the first bistatic radar mapping
of Venus on October 6, using the spacecraft to illuminate the planet
and 70-meter diameter Deep Space Network antennas to listen.
The bistatic technique allows reflected energy to be measured off
the transmitter axis, which can give clues about the composition of
the planet's surface. Some areas on Venus are puzzling because they
retroreflect radar waves more strongly than a diffuse surface would.
The mapping has not been approved yet and has to be scheduled
with the Deep Space Network. On October 6, Earth, Magellan and an
interesting area in Venus are in line, so that measurements can be
made around the transmitter angle. There are several other
opportunities through 1994. Magellan is no longer capable of radar
mapping by itself because failed communications equipment cannot
transmit the imagery data fast enough.
Illumination would be from the spacecraft's X-band and S-band
communications transmitters simultaneously. The X-band signal is
circularly polarized and the S-band is linearly polarized. Having a
range of reflection angles, frequencies, and polarizations will help
the experiment, Gordon H. Pettengill, Magellan radar principal
investigator, said.
The signal should be about 6 dB. louder than noise at Earth when
near the transmitter axis, Pettengill said, and he hopes to be able to
detect the signal when 10 degress off axis.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | The hardest thing to learn
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | in life is which bridge to
|_____|/ |_|/ |_____|/ | cross and which to burn.
|
| 456.595 | Magellan Update -- 08/20/93 | PONIL::J_BUTLER | E pur, si muove... | Mon Aug 23 1993 13:42 | 32 |
|
Forwarded from Doug Griffith, Magellan Project Manager
MAGELLAN STATUS REPORT
August 20, 1993
1. Full-up circular orbit gravity operations began on Monday, August
16th, as the Magellan spacecraft was returned to the High Gain Antenna
(HGA) configuration. In the interim, circular orbit gravity data had
been received via the Medium Gain Antenna (MGA) from August 6th to the
16th.
2. The spacecraft is now performing better thermally than before
aerobraking. It appears that during aerobraking, the spacecraft got a
"cleaning" due to atmospheric scrubbing by atomic oxygen species.
3. As a result of the better thermal performance, cooling periods
using the High Gain Antenna to "hide" the spacecraft from the sun have
been reduced.
Magellan Significant Events for Next Week
1. Last of the High Gain Antenna "hide" periods will be deleted from
the spacecraft orbital profile.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | The hardest thing to learn
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | in life is which bridge to
|_____|/ |_|/ |_____|/ | cross and which to burn.
|
| 456.596 | Magellan Update -- 08/27/93 | PONIL::J_BUTLER | E pur, si muove... | Fri Aug 27 1993 19:09 | 21 |
|
Forwarded from Doug Griffith, Magellan Project Manager
MAGELLAN STATUS REPORT
August 27, 1993
1. Circular orbit gravity operations continue as planned.
2. Spacecraft health and performance remain excellent.
3. As a result of better thermal performance than expected, cooling
periods using the High Gain Antenna to "hide" the spacecraft from the
sun have been eliminated, yielding more gravity data per orbit.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | The hardest thing to learn
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | in life is which bridge to
|_____|/ |_|/ |_____|/ | cross and which to burn.
|
| 456.597 | Aerobraking cleaned the probe | VERGA::KLAES | Quo vadimus? | Wed Sep 15 1993 14:59 | 112 |
| Article: 69994
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space
Subject: Re: Magellan Update - 08/20/93
Date: 22 Aug 1993 18:16 UT
Organization: Jet Propulsion Laboratory
In article <wa2iseCC4DpD.70B@netcom.com>, wa2ise@netcom.com (Robert
Casey) writes...
>In article <20AUG199317104467@kelvin.jpl.nasa.gov>
>baalke@kelvin.Jpl.Nasa.Gov (Ron Baalke) writes:
>>2. The spacecraft is now performing better thermally than before
>>aerobraking. It appears that during aerobraking, the spacecraft got a
>>"cleaning" due to atmospheric scrubbing by atomic oxygen species.
>
>What sort of "dirt" got "cleaned" off the spacecraft? Do spacecraft "grow"
>a "fuzz"? Or solar wind particles chemically react with the skin of the
>probe, and the atomic oxygen removed this?
I'm forwarding these comments from someone on the Magellan team (who
wants to remain anonymous) about Magellan's thermal control:
1. The part of Magellan's thermal control system which would
have the most effect on temperature if its absorbtivity-to-
emissivity ratio changed is the "OSR" tiles, "optically
selective reflectors" which are simultaneously good at
radiating heat and good at reflecting sunlight. It is a
change in these components, possibly due to the darkening
of a layer of oil on their surface due to ultraviolet
radiation damage, which is the suspected cause of Magellan
needing to use shading to control its temperature. Because
of the special behavior of the OSRs, changes in their
surface properties have *much* more effect on the spacecraft
temperature than any credible change in the multilayer
insulation, tape, or paint.
2. OSRs are used on much of the spacecraft's main body and on
both the front and back of the solar arrays. It has not been
possible to find a good explanation of the apparent
contamination of the OSRs from either pre-flight operations
or contamination during the Shuttle launch or IUS burn. One
particularly oddity is that the OSRs on the solar arrays,
which were glued in place using slightly different procedures,
seem to be working normally. while the absorbtivity of the OSRs
on the spacecraft body is much too high. (That is, the OSRs
are absorbing too much sunlight. Their ability to emit
infrared energy appears not to have changed.)
3. Determining whether the OSR behavior has actually changed
after aerobraking may take some time. The circular orbit
operation sequence is new and different from previous
orbital operations. As the relative orientation of the
Earth, Sun, and Venus changes. sunlight will fall on different
parts of the spacecraft. This will allow a comparison of the
observed temperatures with those predicted by the computer
model with differing OSR parameters.
Put simply: It may be premature to say that the OSR parameters
or other characteristics of the thermal control system have
been changed by aerobraking.
On the other hand, it is not physically impossible that
atomic oxygen bombardment during aerobraking might act to
clean the surfaces of the quartz tile OSRs of any contamination.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | The hardest thing to learn
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | in life is which bridge to
|_____|/ |_|/ |_____|/ | cross and which to burn.
Article: 69947
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space
Subject: Re: Magellan Update - 08/20/93
Date: 22 Aug 1993 03:35 UT
Organization: Jet Propulsion Laboratory
In article <wa2iseCC4DpD.70B@netcom.com>, wa2ise@netcom.com (Robert
Casey) writes...
>In article <20AUG199317104467@kelvin.jpl.nasa.gov>
>baalke@kelvin.Jpl.Nasa.Gov (Ron Baalke) writes:
>>2. The spacecraft is now performing better thermally than before
>>aerobraking. It appears that during aerobraking, the spacecraft got a
>>"cleaning" due to atmospheric scrubbing by atomic oxygen species.
>
>What sort of "dirt" got "cleaned" off the spacecraft? Do spacecraft "grow"
>a "fuzz"? Or solar wind particles chemically react with the skin of the
>probe, and the atomic oxygen removed this?
Thermal control is performed on Magellan by wrapping the electronics
housings in thermal blankets that insulate and reflect light. Most of
the rest of the spacecraft is painted with a special inorganic paint
to withstand and reflect the solar light. The temperatures on the
spacecraft was higher than expected, so the spacecraft had to shade
itself periodically from the Sun using the High Gain Antenna. Exactly
why Magellan was experiencing the higher than expected temperatures is
not really known, but it may have been due to discoloring of the paint
or the astroquartz (the outer layer of the thermal blankets). Whatever
the cause, repeated passes of the spacecraft through the upper atmosphere
during the aerobraking has improved its thermal protection.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | The hardest thing to learn
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | in life is which bridge to
|_____|/ |_|/ |_____|/ | cross and which to burn.
|
| 456.598 | New radar images | VERGA::KLAES | Quo vadimus? | Thu Sep 30 1993 14:58 | 48 |
| From: US1RMC::"DOKERSON@hq.nasa.gov" "MAIL-11 Daemon" 29-SEP-1993 21:27:27.42
To: sci-space-news@ames.arc.nasa.gov
CC:
Subj: New Magellan JPEGs available
Ten new image mosaics from NASA's Magellan mission to Venus have been
placed online for anonymous FTP access at ames.arc.nasa.gov in
pub/SPACE/JPEG. These images show the "browse" images from the most
recently released Magellan CD-ROM, CD-80. On the CD itself, these images
are in VICAR format, and provide low-resolution overviews of the areas
shown in 56 tiles for each mosaic.
Since these are direct digital-to-digital images, their quality is
excellent. Each image is 1024x768 pixels. The JPEG format allows each
image to be stored in only about 200 kilobytes; the corresponding GIF
images are about four times larger. Each image corresponds to a Magellan
"full resolution" mosaic, with 75 meter spacing between pixels (in the CD
tiles). The file names are each of the form "f10n032.jpg", indicating the
mosaic type, latitude, north or south, and the (east) longitude of the
mosaic's center.
The VICAR originals provide an ASCII "header", which allows display
software to show, for example, the latitude/longitude of individual pixels,
but this information is not provided by these JPEG files. The brightness
values for these JPEG images have been linearly stretched to produce a good
contrast range. Thus, these files do not preserve the "calibration" of the
original files, for which a specific pixel value corresponds to a
particular radar reflectivity.
Magellan CD-ROMs of radar images, altimeter, and radiometer data can be
requested through e-mail to request@nssdc.gsfc.nasa.gov. NSSDC also has a
wide range of other Magellan materials, including photographs, maps, and
computer flyover videotapes. Magellan mapped over 98 percent of Venus's
surface during its first 3 mapping cycles (24 months). NSSDC also has the
measurements of Venus's gravity field collected during the fourth cycle.
The Magellan spacecraft is currently collecting measurements of Venus's
gravity field from its new near-circular orbit. These measurements show
the distribution of dense and light regions inside the planet, with equal
resolution and sensitivity over the entire globe. This variation in
internal density reflects principally variations in temperature, and thus
will reveal the internal structure and motions responsible for the surface
features already mapped. Magellan is also measuring the density of the
planet's high atmosphere through drag and torque on the spacecraft. On
October 6, a special "bistatic" radar experiment is planned, illuminating
Venus's surface with the X and S-band radio downlinks from the spacecraft
and receiving the reflection on Earth.
|
| 456.599 | MAGELLAN data software available | VERGA::KLAES | Quo vadimus? | Tue Nov 02 1993 14:26 | 99 |
| From: US1RMC::"VOLCANO%ASUACAD.BITNET@uga.cc.uga.edu" "VOLCANO"
2-NOV-1993 11:22:07.97
To: Multiple recipients of list VOLCANO
<VOLCANO%ASUACAD.BITNET@uga.cc.uga.edu>
CC:
Subj: Magellan Software Announcement
The Geoscience Node of the Planetary Data System is pleased to announce
the release of the following peer-reviewed software for the scientific
analysis of Magellan data sets on the Apple Macintosh [see notes 1,2].
________________________________________________________________
Title: Magellan HyperMap and Experimenters' NotePad
Format: Hypercard stacks
Requires: Apple Macintosh with OS system 6.0.7 or 7.x
At least 1 Mbyte RAM (2 Mbytes for system 7.x)
3.4 megabytes of disk space
Claris Hypercard version 2.1 (or later)
Optional: Image display program, e.g. Image4pds, PixelPusher
________________________________________________________________
The HyperMap and NotePad are a pair of Hypercard "stacks", i.e.
interactive hypertext databases, containing much useful information
about Venus surface features, Magellan data sets, and radar instrument
parameters. They can be used alone -- e.g. to locate MIDR, BIDR,
GxDR, or ARCDR products by feature name or by latitude and longitude
-- or, if a suitable image display program is available -- e.g.
NIH/Image or PixelPusher -- they can display the selected images
directly.
Write to the address below for a copy of this software on a 3.5"
high-density (1.4 Mbyte) floppy disk. Alternatively, and preferable
to us, you can copy it directly [see note 3] via anonymous FTP:
Host: delcano.mit.edu [18.75.0.80]
Userid: anonymous
Password: any (please use your e-mail address)
Directory: mgn/software/hyperware
File: hypermap.hqx
This is a compressed file containing only ASCII characters. The file
"hypermap.txt" in the same directory describes how to unpack it onto
your Macintosh, and the file "hypermap.notes" lists the current status
of all known problems. If you find a bug in these stack, or wish to
suggest improvements, please send mail or e-mail to:
Dr. Peter G. Ford
Center for Space Research
MIT 37-601
Cambridge, MA 02138
USA
____________________________
Datafax: 1-617-253-0861
Internet: pgf@space.mit.edu
NASAMAIL: PFORD (or ID:PFORD,PRMD:NASAMAIL,ADMD:TELEMAIL,C:USA)
NSI/DECNET: JPLPDS::PFORD
_________________________________________________________________________
Notes:
[1] The HyperMap and NotePad contain a subset of the data that are stored
in the "Magellan Standard Products Catalog", an on-line database which
you can reach via "telnet" or "rlogin" to:
Host: wufs.wustl.edu [128.252.144.28]
Userid: mgnuser
Password: ?magellan
This catalog also includes an "order" option, whereby you can place
orders for the delivery of Magellan data sets as magnetic tapes, compact
disks (CD-ROM), and photographic prints.
[2] MS-DOS users should also be aware of the following database, with many
of the features of the HyperMap and NotePad, available via anonymous FTP:
Host: ames.arc.nasa.gov [128.102.18.3]
Userid: anonymous
Password: any (please use your e-mail address)
Directory: /pub/SPACE/SOFTWARE
File: magellan.zip
[3] NSI/DECNET (i.e. SPAN) users without Internet access can receive the
software by specifying the following source pathname in a VMS COPY
command:
EAST"ftp@delcano.mit.edu passwd"::"mgn/software/hyperware/hypermap.hqx"
where the quotes are essential and "passwd" should be replaced with
a current e-mail address, e.g "host::user".
_________________________________________________________________________
% ====== Internet headers and postmarks (see DECWRL::GATEWAY.DOC) ======
% Date: Tue, 2 Nov 1993 09:18:09 MST
% Sender: VOLCANO <VOLCANO%ASUACAD.BITNET@uga.cc.uga.edu>
% From: "Peter G. Ford" <pgf@space.mit.edu>
% Subject: Magellan Software Announcement
% To: Multiple recipients of list VOLCANO
|
| 456.600 | Magellan Update 11/12/93 | PONIL::J_BUTLER | E pur, si muove... | Thu Nov 18 1993 18:10 | 26 |
|
Magellan Significant Events for Week Ending 11-12-93:
1. The Magellan spacecraft performance is nominal and continues to
provide a good radio signal for doppler tracking to obtain high-
resolution gravity data.
2. A successful bistatic radar experiment was performed on November 9
and the quasi-specular signal reflection from the Venusian surface was
seen in the DSN open loop receivers.
3. The 43rd meeting of the Project Science Group was held on Tuesday,
November 9.
4. Over 50 Magellan friends attended the party honoring "three famous
scientists" - Project Scientist Steve Saunders, Deputy Project Scientist
Ellen Stofan, and Science and Mission Planning Office Manager Tommy
Thompson - on Monday evening. Also being honored was David Okerson,
Program Engineer at NASA Headquarters. These key individuals have moved
on to new assignments.
Magellan Significant Events for Next Week:
1. The spacecraft batteries will be reconditioned for the third time.
|
| 456.601 | Magellan Update 11/19/93 | PONIL::J_BUTLER | E pur, si muove... | Mon Nov 22 1993 12:38 | 29 |
|
Magellan Significant Events for Week Ending 11-19-93:
1. The Magellan spacecraft performance is nominal and continues to
obtain high-resolution gravity data.
2. The third spacecraft battery reconditioning maintenance activity
started on November 15 with Battery #1. Battery #1 activity was
completed on schedule and returned to service on November 19. At that
time reconditioning of Battery No. 2 was started.
3. A successful NO-RAMP uplink test was carried out on November 18
between the DSN and Magellan spacecraft. This is an effort to improve
the radio uplink acquisition process on Magellan. This process is
expected to be simpler and more reliable while still meeting Magellan
uplink requirements. A decision on changing the uplink process will
be made next week after final tracking data evaluation.
Magellan Significant Events for Next Week:
1. Spacecraft battery reconditioning will be completed on Tuesday,
November 23.
2. On Friday, November 26, Magellan will complete ten thousand (10000)
orbits about Venus.
3. There will be NO Magellan Significant Events report for Thanksgiving
week unless unexpected events occur.
|
| 456.602 | Magellan Update 12/03/93 | CXDOCS::J_BUTLER | E pur, si muove... | Sun Dec 05 1993 12:12 | 19 |
|
Magellan Significant Events for Week Ending 12/03/93
1. The Magellan spacecraft performance is nominal and continues to
obtain high-resolution gravity data.
2. The spacecraft continues to perform a maneuver on every other orbit
to warm the critical electronic systems. Transmitter B is maintained at
51 deg. C. and gyro A2 is at 55 deg. C.
3. The no-ramp procedure for establishing communcation lock between the
DSN and Magellan spacecraft has resulted in improved processing of the
doppler data to extract the gravity signature. By maintaining a constant
frequency during the tracking pass, the calculations are simplified.
Magellan Significant Events for Next Week
1. High-resolution gravity data acquisition will continue.
|
| 456.603 | Update - December 10 | VERGA::KLAES | Quo vadimus? | Mon Dec 13 1993 18:10 | 27 |
| Article: 5129
Newsgroups: sci.space.news
From: sdd@larc.nasa.gov (Steve Derry)
Subject: Magellan Status 12/10/93
Sender: digester@news.arc.nasa.gov
Organization: NASA Langley Research Center, Hampton, VA USA
Date: Fri, 10 Dec 1993 20:48:21 GMT
Magellan Significant Events for Week Ending 12/10/93
*1. The Magellan spacecraft performance is nominal and continues to obtain
high-resolution gravity data. Temperatures are in the expected range.
2. As of today Magellan has obtained high-resolution gravity data over
187 degrees of longitude or 52% of the global coverage.
*3. Results of the gravity mission to date were presented in a press
conference at the American Geophysical Union meeting in San Francisco on
Tuesday. Principal investigator William Sjogren was the featured presenter.
4. Magellan has completed 10,214 orbits since entering Venus orbit in
August 1990. It orbits 15.3 times per Earth day.
Magellan Significant Events for Next Week
1. Magellan is expected to continue nominal operations.
|
| 456.604 | Spring 1994 AGU Session on Venus volcanoes | VERGA::KLAES | Quo vadimus? | Thu Dec 23 1993 15:09 | 55 |
| From: US1RMC::"VOLCANO@asuvm.inre.asu.edu" "VOLCANO" 22-DEC-1993 21:22:52.82
To: Multiple recipients of list VOLCANO <VOLCANO@asuvm.inre.asu.edu>
CC:
Subj: Please Post - Spring AGU Session
Roger Phillips and I are organizing the following session for Spring
AGU. The abstract deadline is March 3. Many of the issues here are
related to volcanology and the volcanic record on Venus. Even if you
are not a planetary volcanology person, I encourage you to attend
because many of these issues may be extremely relevant to the early
Earth. Please contact me if you want any further information. - Jim Head
P01 Is Venus Past It's Prime? - Joint with T,V
Venus is apparently not what it used to be. A wide variety of
evidence suggests that what we observe on this planet may be a relic
of a volcanic and tectonic style that is not operating today. The
style of volcanism seems to have changed from plains or flood to
constructional. Tesserae may underlie much of the plains indicating
that at one time this terrain type dominated the surface of the
planet. Crater studies indicate that much of the high-standing
tesserae are older than the mean age of the planet. The rate of
planetary resurfacing seems to have declined. Gravity studies indicate
that much of the topography may be supported in the lithosphere,
overturning earlier results indicating a large component of deep
dynamic support for many features.
The purpose of the session is to bring together views from different
disciplines to focus on this question from observational studies,
modeling, and theoretical considerations. Contributions synthesizing a
variety of approaches into a coherent model of the secular behavior of
Venus over the past billion years are especially encouraged.
Conveners: Roger J. Phillips, Dept. of Earth & Planetary Sciences,
Washington Univ., Box 1169, St. Louis, MO, 63130, tel.: (314)
935-6356, fax: (314) 935-7361, e-mail: phillips@wustite.wustl.edu;
James W. Head III, Dept. of Geological Sciences, Brown Univ., P.O. Box
1846, Providence, RI 02912, tel.: (401) 863-2526, fax: (401) 863-3978,
E-mail: head@pggipl.geo.brown.edu
---------------------------------------------------------------------------
Dr. James W. Head III
Department of Geological Sciences
Brown University, Box 1846
Providence, Rhode Island 02912
Span/DecNet PGGIPL::Head
Internet HEAD@PGGIPL.GEO.BROWN.EDU
% ====== Internet headers and postmarks (see DECWRL::GATEWAY.DOC) ======
% Date: Wed, 22 Dec 1993 19:17:43 -0700 (MST)
% From: Jim Head <HEAD@PGGIPL.GEO.BROWN.EDU>
% Subject: Please Post - Spring AGU Session
% Sender: VOLCANO <VOLCANO@asuvm.inre.asu.edu>
% To: Multiple recipients of list VOLCANO <VOLCANO@asuvm.inre.asu.edu>
|
| 456.605 | Magellan Update -- 01/07/94 | CXDOCS::J_BUTLER | E pur, si muove... | Sun Jan 09 1994 11:30 | 16 |
|
Magellan Significant Events for Week Ending 1/07/94
1. The Magellan spacecraft performance is nominal, and all starcals
during the holiday period were successful. The spacecraft will pass
through Superior Conjunction on Jan. 16th, at which time the SEP angle
will be 0.9 degrees.
2. The spacecraft is in a period of apoapsis solar occultation which
started Dec. 7, and spends 58 minutes of alternate 94-minute orbits in
an attitude to heat the -X face of the spacecraft to assure proper
operating temperatures for the gyros.
3. As of today Magellan has completed 10640 orbits of Venus, 2396
orbits since achieving a near circular orbit on Aug. 3, 1993.
|
| 456.606 | MAGELLAN data location | VERGA::KLAES | Quo vadimus? | Tue Jan 11 1994 21:35 | 86 |
| Article: 81140
From: pgf@space.mit.edu (Peter G. Ford)
Newsgroups: sci.space
Subject: Re: Venus data
Date: 11 Jan 1994 17:06:12 GMT
Organization: MIT Center for Space Research
In article 1@cs.cmu.edu, RPHMBRUS@idbsu.idbsu.edu (Micky kBrus) writes:
>Can anyone tell me the name of the file that contains the Magellan
>telemetry data? I think it is at Ames Research Center..about 15 MB worth
>of data. I've seen it before but lost the name and location. Also, about
>a year ago someone posted that he had tried to plug the data into a flight
>simulator and it actually placed him on the surface of Venus, although the
>frame rate was very slow. Please let me know if any one else has tried this.
You won't find any Magellan "telemetry" data sets on-line -- they are
rather indigestible. Instead, there are a number of processed data sets
out there, most of them MUCH larger than 15 Mbytes.
The current set of Magellan CD-ROMs comprises 123 image disks (mg_0001
through mg_0123), 19 raw altimetry disks (mg_2001 through mg_2019), and
one topographic image disk (mg_3002). A disk containing polar images is
scheduled for release later this year. All can be purchased from the
National Space Science Data Center which you can reached by telnet to
"nssdca.gsfc.nasa.gov" (log in as "nodis"), or by sending e-mail to
"request@nssdca.gsfc.nasa.gov" or by or using WWW software to view
"http://hypatia.gsfc.nasa.gov/CRUSO/cdrom.html".
Some of these CD-ROMs are also available on-line...
Look in the "cdrom/magellan" sub-directory of explorer.arc.nasa.gov.
Each sub-directory is an entire CD-ROM. Currently mg_0001-mg_0048 and
mg_2001-mg_2010 are mounted. Each radar image disk contains ten image
frames, each frame is sub-divided into 56 framelets, and each framelet
contains 1024x1024 pixels.
The topographic and surface-property disk, mg_3002, is permanently
mounted as "mgn/DATA/GxDR" on delcano.mit.edu. The disk contains 4
types of image: topography, emissivity, roughness, and reflectivity.
Each type is represented by four images: equatorial, polar, and
whole-planet, a total of 72 framelets, each of 1024x1024 pixels.
Low-resolution GIF versions of several of these images are located in
"mgn/DATA/GIF". Look in the "mgn/doc" directory for more details.
At some future time, we hope to make more Magellan data available,
starting with the high-resolution image strips that were used to
construct the radar mosaics, and the raw altimetry telemetry.
A number of people have asked us how to load the topography images into
3-D simulators, e.g. VistaPro. We have been unable to help them since
we are unfamiliar with these products. If anyone out there has been
successful, please post to the net, or mail us the details so we can
help others.
Peter G. Ford
Microwave Subnode
NASA Planetary Data System.
<pgf@space.mit.edu>
Article: 81151
Newsgroups: sci.space
From: martin@space.ualberta.ca (Martin Connors)
Subject: Re: Venus data
Sender: news@kakwa.ucs.ualberta.ca
Organization: University Of Alberta, Edmonton Canada
Date: Tue, 11 Jan 1994 19:09:58 GMT
You are probably referring to the explorer.arc.nasa.gov machine, where
magellan data is kept in cdrom/magellan (other probes' data in other
directories). There are 48 image disks or roughly 31 Gigabytes of data
for images, and about 5-6 gigs of ARCDR which is fairly close to
telemetry for various RADAR parameters (elevation, etc.). Clearly a
major problem is accessing the data you want and there are tools to do
this to be found on ames.arc.nasa.gov - you'll need to get their index.
It is not clear how any of this would go into a flight simulator. It
may be possible to put elevation files into VistaPro, but as far as I
know this CDROM (GxDR) is not mounted at explorer.arc.nasa.gov.
Hope this helps.
--
Martin Connors |
Space Research | martin@space.ualberta.ca (403) 492-2526
University of Alberta | "the Secretary will disavow any knowledge..."
|
| 456.607 | Magellan Update -- w/e 01/14/94 | CXDOCS::J_BUTLER | E pur, si muove... | Tue Jan 25 1994 10:50 | 27 |
|
Magellan Significant Events for Week Ending January 14, 1994
1. The Magellan spacecraft continues to perform well in its 161st day
of circular orbit operations at Venus and will pass through Superior
Conjunction next Sunday afternoon (Jan. 16th).
2. The spacecraft temperatures remain in the predicted range. The
radar heaters have been turned off to conserve power, because the
spacecraft spends almost half of every orbit in the shadow of Venus.
Also, the spacecraft spends 58 minutes of every other orbit in a
heating attitude to allow the sun to warm the critical electronic
equipment in Bay 7.
3. The spacecraft team and mission planners are presently designing
the End-of-Mission experiments which will be performed either at the
end of April or October this year, depending on project funding.
4. As of noon today Magellan has completed 10746 orbits of Venus. It
will complete its fifth cycle of Venus on April 17, 1994, and its 5th
year in space on May 5th.
Events Expected Next Week
1. Magellan will pass within 0.9 degrees of the the solar disk on
January 16th.
|
| 456.608 | Magellan Update -- w/e 01/28/94 | PONIL::J_BUTLER | E pur, si muove... | Mon Jan 31 1994 13:11 | 18 |
|
Magellan Significant Events for Week Ending 1/28/94
1. The Magellan spacecraft has resumed high-resolution gravity data
acquisition and continues to perform nominally.
2. Approximately 10 to 14 days of usable doppler tracking data was lost
during Superior Conjunction as the Sun-Earth-Probe angle reached its
minimum of 0.9 degree on January 16th.
3. The spacecraft team and mission planners are continuing to design the
End-of-Mission experiments which will be performed either at the end of
April or September this year, depending on project funding.
4. Magellan was again honored with the Aviation Week 1993 Laurels award
for the unique planetary aerobraking maneuvers performed between May and
August 1993. Magellan was previously honored in 1989.
|
| 456.609 | February 18 | VERGA::KLAES | Quo vadimus? | Mon Feb 21 1994 17:42 | 24 |
| Article: 5379
Newsgroups: sci.space.news
From: sdd@larc.nasa.gov (Steve Derry)
Subject: Magellan Status 2/18/94
Sender: digester@news.arc.nasa.gov
Organization: NASA Langley Research Center, Hampton, VA USA
Date: Fri, 18 Feb 1994 20:45:49 GMT
Magellan Significant Events for Week Ending 02/18/94
1. The Magellan spacecraft continues high-resolution gravity data
acquisition and is performing nominally.
2. Following the unsuccessful test of the subcarrier modulation on
transmitter B, the mission planners decided to cancel the high-resolution
altimetry experiment proposed for early June.
3. The primary science objective for the remainder of the Magellan
mission is the filling of high-resolution gravity coverage, especially
during the August to November period.
4. As of noon Friday, February 18th, Magellan has completed 11280 orbits
of Venus, including 3037 circular-gravity orbits.
|
| 456.610 | MAGELLAN stays alive | VERGA::KLAES | Quo vadimus? | Mon Feb 21 1994 17:46 | 89 |
| From: US1RMC::"Admin@ccmail.jpl.nasa.gov" "JPL Public Information"
21-FEB-1994 14:43:33.37
To: sci-space-news@uunet.uu.net
CC:
Subj: JPL/Magellan funding extended
PUBLIC INFORMATION OFFICE
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIF. 91109. TELEPHONE (818) 354-5011
Contact: Jim Doyle
FOR IMMEDIATE RELEASE February 21, 1994
NASA's Magellan mission to Venus has received additional
funding in fiscal year 1994 to complete gravity studies of
Earth's sister planet through September.
Magellan has exceeded its original mission goals, and NASA
plans to cease operations at the completion of gravity mapping.
The money will allow the flight team to acquire high-
resolution gravity data over 90 percent of the planet as well as
to conduct atmospheric and radio science experiments, said Doug
Griffith, Magellan project manager at NASA's Jet Propulsion
Laboratory.
Deputy Project Scientist Dr. Ellen Stofan told an American
Association for the Advancement of Science meeting in San Francisco
that the funding would provide for continued gravity mapping.
She also described possible future new steps in Venus
exploration -- possibly with rovers, landers and high-tech
devices capable of operating in the forbidding Venus environment.
Griffith said the project team hopes to reduce ongoing
operational costs to enable spacecraft operations to continue
through October, thereby obtaining high-resolution gravity
coverage of 97 percent of Venus.
The high-resolution gravity data were made possible as a
result of a daring maneuver, called aerobraking, which placed the
spacecraft into a near-circular orbit last summer.
Magellan was the first orbiting planetary spacecraft to use
atmospheric drag, or aerobraking, to change its orbit. The
aerobraking technique pioneered by Magellan will be used by the
NASA/JPL Mars Surveyor orbiter -- planned for launch in 1996 --
to lower its orbit when it arrives at Mars in November 1997.
Mars Surveyor is a new mission included in President
Clinton's budget for fiscal year 1995, which begins next October.
Launched in May 1989 from the space shuttle Atlantis, the
Magellan spacecraft arrived 15 months later at Venus. It was
placed in a highly elliptical orbit from which it used imaging
radar to map 98 percent of the planet's surface.
Starting in May 1993, thruster firings were used to lower
Magellan's periapsis -- the point in its orbit closest to Venus
-- from 300 kilometers (185 miles) to 140 kilometers (87 miles),
just skimming the planet's thin upper atmosphere.
Carefully controlled atmospheric drag over the next 70 days
was then used to lower Magellan's apoapsis -- the outermost point
in its orbit -- from 8,340 kilometers (5,170 miles) to 540
kilometers (335 miles).
With the near-circular orbit, Magellan was positioned to
make gravity measurements at the planet's mid- and higher
latitudes as well as at equatorial regions.
Magellan completed its original primary mission between
August 1990 and May 1991 by returning radar images covering at
least 70 percent of Venus's surface. The mission exceeded that
goal and went on to map 98 percent of the planet. Magellan ended
the radar mapping portion of its operation in September 1992.
Gravity mapping began in the planet's equatorial band for a
full 243-day orbital cycle, or one Venus day. Gravity mapping in
the near-circular orbit began August 16, 1993.
#####
2-18-94 JJD
#9411
|
| 456.611 | Wearing down | JVERNE::KLAES | Be Here Now | Wed Mar 16 1994 17:54 | 159 |
| Article: 54074
From: sdd@larc.nasa.gov (Steve Derry)
Newsgroups: sci.space,sci.astro,alt.sci.planetary
Subject: Re: Why stop now? (was Re: Magellan Mission Extended)
Date: 10 Mar 1994 23:26:10 GMT
Organization: NASA Langley Research Center, Hampton, VA USA
The reasons for shutting down Magellan fall into two categories:
technical problems on the spacecraft, and budgetary constraints.
Magellan's radar is (as far as I know) still fully functional, although
it is no longer being used. The (technical) problems with using the
radar are in transmitting the radar back to Earth. One transmitter has a
noise problem -- a spurious signal which interferes with the high-rate
data subcarrier. The other transmitter's high-rate modulator has failed
entirely. This transmitter can still send a perfectly good carrier for
tracking, which is used for the gravity mapping. So technically, getting
any SAR (synthetic aperture radar) data back to Earth is very
challenging, if not impossible. Several bistatic radar experiments have
been performed, and several others are proposed over the balance of the
mission. With bistatic radar, Magellan sends a signal towards the
surface of Venus such that it reflects back toward Earth. The reflected
signal is then received by ground stations.
The real reason for shutting down Magellan is cost. Operating the SAR,
even if it were possible, requires significant staff (equals significant
dollars). For this reason alone, SAR operations are out. The Magellan
team has been pared down to the core so that the current gravity-mapping
operations are being conducted with minimal staff on a minimal budget.
Once the high-resolution gravity mapping is complete, it is not clear
where any significant new science can be accomplished with Magellan in
its present condition. With upcoming budgets getting increasingly
tighter, it only makes sense to stop funding a mission which has
successfully completed its mission but has little else that it can do
that it hasn't already done.
By the way, Magellan just got an extension a couple months ago to
complete the high-res gravity mapping because the project was able to
demonstrate that it can produce meaningful results at minimal cost. That
job will be finished in October. Afterwards, a few end-of-mission
experiments are being looked at. (Anybody have any details?)
--
Steve Derry
<s.d.derry@larc.nasa.gov>
Article: 54206
From: malin@esther.la.asu.edu (Mike Malin)
Newsgroups: sci.astro
Subject: Re: Magellan Mission Extended
Date: 12 Mar 94 16:36:46
Organization: TES Project, ASU, Tempe AZ
To the question, "Why not continue Venus mapping with Magellan?",
James Acker wrote "I'm pretty sure the mapping radar instrument
essentially burned out." Richard Ottolini responded "No. Congress
deleted it from the budget." Both are correct: the SAR is no longer
operational and at the end of roughly September all but 1 or 2% of the
gravity field will have been mapped from the low circular orbit (and
that 1-2% will have been mapped from slight higher altitude, and hence
slightly lower resolution). In anticipation of winding down at the
end of the mission, NASA has not requested additional funds nor has
Congress authorized them. This, of course, does not address past
differences between what scientists wanted to do, what NASA wanted to
do, and what Congress wanted to do. But at this point, I believe,
everyone is pretty much in accord.
Mike Malin
ex-Mars Observer Camera Principal Investigator
sometime Magellan Guest Investigator
Article: 54233
From: pgf@space.mit.edu (Peter G. Ford)
Newsgroups: sci.space,sci.astro,alt.sci.planetary
Subject: Re: Magellan Mission Extended
Date: 14 Mar 1994 00:08:45 GMT
Organization: MIT Center for Space Research
In article <2lq6g1$4s@paperboy.gsfc.nasa.gov>
jgacker@news.gsfc.nasa.gov (James G. Acker) writes:
>Richard Ottolini (stgprao@st.unocal.COM) wrote:
>: In article <2lntue$d6n@paperboy.gsfc.nasa.gov>,
>: James G. Acker <jgacker@news.gsfc.nasa.gov> wrote:
>: > I'm pretty sure the mapping radar instrument (the SAR)
>: >essentially burned out. The gravity mission is just based on
>: >altitude above the surface.
>: No. Congress deleted it from the budget. It would have cost another
>: $40M to collect and process the data. Not much compared to a billion
>: mission, but too much for Congress.
> You're right. Even though the radar was malfunctioning, it
>was still usable. So they went with the cheaper gravity mission and
>snuck it through. Sorry to have been mis-informative.
Still not quite right! The radar aboard Magellan has functioned
flawlessly from start to finish. It is dual-string redundant, i.e. it
is built in 7 sections, each of which is duplicated and can be used in
case the primary unit fails. None ever failed. Half of the radar was
never even switched on!
The major failure occurred in the modulation units of the two telemetry
transmitters, which are part of the spacecraft system and have nothing
to do with the radar. These units take the radar signals from the
on-board tape recorder (originally two of them, but one failed), and
encode them on the downlink transmitter carriers.
One of the modulators died and the other went into parasitic
oscillations (a so-called "frequency spur") which scrambled the
downlink data transmissions and robbed power from what little signal
got through. The degradation was progressive. It had become so bad by
September 1992 that the Project decided to switch it off and
concentrate on gravity mapping, which uses the downlink transmitters
but without the modulators.
Sure, we could try to use the modulator again, but the chances of
getting any useful data back are rather slim. In these times of
planetary belt-tightening, many people argue that the money is
better spent analyzing the existing data.
Peter Ford
MIT and Magellan Project
Article: 54364
Newsgroups: sci.space,sci.astro,alt.sci.planetary
From: henry@zoo.toronto.edu (Henry Spencer)
Subject: Re: Magellan Mission Extended
Date: Tue, 15 Mar 1994 20:18:13 GMT
Organization: U of Toronto Zoology
In article <CMH5r7.3v6@unocal.com> stgprao@st.unocal.COM (Richard
Ottolini) writes:
>At some point Magellan would have run out of manuevering fuel.
>The same attenna for collecting radar data was used to transmit the
>results to earth, so Magellan turned to face earth every orbit.
Yes, but it used reaction wheels for the turns. It used fuel only to
counteract long-term "secular" (non-cyclic) torques, from things like
atmospheric drag and light pressure. Its fuel supply is finite, but
that doesn't currently look like a serious limitation.
As others have said, the big problem is that getting radar data back
to Earth, through the ailing modulator, requires drastic measures that
imply nursing the spacecraft along very carefully. There have been one
or two proposals to do a little bit of this for high-priority targets,
but any major resumption of mapping is out of the question. The effort
is out of proportion to the value of the data.
So Magellan is pretty much restricted to doing things that don't require
returning radar data to Earth. And Magellan, unlike traditional NASA
planetary missions, is basically a single-instrument spacecraft. There
are a few things that can be done with the radar without returning radar
data, like gravity mapping and occasional bistatic radar work (when the
geometry is favorable). Once you finish with those, you've pretty much
exhausted Magellan's scientific usefulness.
--
Belief is no substitute | Henry Spencer @ U of Toronto Zoology
for arithmetic. | henry@zoo.toronto.edu utzoo!henry
|
| 456.612 | Magellan Update -- w/e 04 Mar 1994 | CXDOCS::J_BUTLER | E pur, si muove... | Sun Apr 03 1994 11:15 | 19 |
|
Magellan Significant Events for Week Ending 03/04/94
1. The Magellan spacecraft continues high-resolution gravity data
acquisition and is performing nominally.
2. Mission operations are now expected to continue to the end of
October. A decision on the mission ending "windmill" experiment and
ending state of the spacecraft is still pending.
3. Mission planners predict that we will achieve 97% high-resolution
gravity data coverage of Venus in circular orbit by early October.
Events Expected Next Week
1. In addition to continuing gravity data collection, two Orbital Trim
Maneuvers (OTMs) will be performed on March 10th to lower periapsis by 22
km in order to provide better aeronomy data.
|
| 456.613 | Magellan Update -- w/e 11 March 1994 | CXDOCS::J_BUTLER | E pur, si muove... | Sun Apr 03 1994 11:16 | 13 |
|
Magellan Significant Events for Week Ending 03/11/94
1. The Magellan spacecraft continues high-resolution gravity data
acquisition and is performing nominally.
*2. Thursday, March 10th, two Orbit Trim Maneuvers were successfully
performed to lower the periapsis by about 24 km to provide improved
aeronomy data.
3. Magellan has completed 11600 orbits of Venus since it arrived at the
planet on August 10, 1990.
|
| 456.614 | Magellan Update -- 18 March 1994 | CXDOCS::J_BUTLER | E pur, si muove... | Sun Apr 03 1994 11:17 | 14 |
|
Magellan Significant Events for Week Ending 03/18/94
1. The Magellan spacecraft continues to perform nominally and gather
high-resolution gravity data.
2. The Magellan "end-of-mission plan" has received preliminary verbal
concurrence by Code SL. The plan must still be approved by Code S and
Code A. Under this plan we would continue high-resolution gravity data
collection, radio science and aeronomy through early October, followed by
a "windmill experiment" which will cause the spacecraft to enter and burn
up in Venus' atmosphere. Mission operations would end by October 31,
1994 and the project closed down by late January 1995.
|
| 456.615 | Magellan Update -- w/e 25 March 1994 | CXDOCS::J_BUTLER | E pur, si muove... | Sun Apr 03 1994 11:18 | 18 |
|
Magellan Significant Events for Week Ending 03/25/94
1. The Magellan spacecraft continues to perform nominally.
2. Following the OTMs on March 10, spacecraft controllers noticed small
fluctuations in the motor current for gyro B1. The B1 motor current has
now returned to a steady and expected performance.
3. Similar fluctuations have been seen on other gyros and, in some
cases, led to declining performance which required switching to redundant
units. The loss of any one of the remaining gyros would very likely end
the mission.
4. As of noon Friday, Magellan has completed 11825 orbits (78%) of the
15140 orbits it is expected to complete by the End-of-Mission (October
31, 1994).
|
| 456.616 | Magellan Update -- w/e 01 April 1994 | CXDOCS::J_BUTLER | E pur, si muove... | Sun Apr 03 1994 12:46 | 36 |
| Article: 5488
From: sdd@larc.nasa.gov (Steve Derry)
Newsgroups: sci.space.news
Subject: Magellan Status - 04/01/94
Date: 2 Apr 1994 08:28:57 -0800
Organization: NASA Langley Research Center, Hampton, VA USA
Sender: daemon@news.arc.nasa.gov
Magellan Significant Events for Week Ending 04/01/94
1. The Magellan spacecraft went into CDS safing on Monday, March 28th,
when it tried to execute an invalid instruction. The spacecraft was back
in normal operations with S-band communications by mid-Monday, and X-band
communications were restored on Tuesday.
2. The incident was caused by a delayed command uplink to perform a
memory readout which over-wrote a portion of active memory earlier on
March 16th. Procedures to avoid a recurrence have been implemented.
3. During the four orbits in safing the spacecraft cooled down since it
was not performing the "heat" maneuvers on each orbit, but all systems
were nominal including the gyros which had exhibited fluctuating motor
currents when temperatures got below 50 deg. C.
4. The orbit number reached 12000 on Wednesday, March 30th. (The
actual count, however, is 111 orbits less since the numbering started at
100 and was adjusted by 11 during the early in-orbit checkout.)
Magellan Significant Events for Next Week
1. Between April 4th and April 12th, 1994, 10 Orbit Trim Maneuvers
(OTMs) will be performed to change the orbit from approximately 530 x 184
km to 390 x 220 km in order to improve the data acquired by the gravity
experiment (on the apoapsis side of the orbit).
|
| 456.617 | April 5 | JVERNE::KLAES | Be Here Now | Tue Apr 05 1994 21:36 | 33 |
| Article: 5502
From: Admin@ccmail.Jpl.Nasa.Gov
Newsgroups: sci.space.news
Subject: Magellan status 4/5/94
Date: 5 Apr 1994 13:45:09 -0700
Organization: Jet Propulsion Laboratory - Pasadena CA
Sender: daemon@news.arc.nasa.gov
PUBLIC INFORMATION OFFICE
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIF. 91109. TELEPHONE (818) 354-5011
MAGELLAN STATUS REPORT
April 5, 1994
Magellan Project engineers Monday began trim maneuvers for the
Magellan spacecraft to bring it into a more circular orbit about
Venus. Magellan is in its fifth 243-day cycle, currently studying the
planet's gravity. A cycle is one rotation of Venus on its axis. The
spacecraft begins a sixth orbital cycle on April 14.
The trim maneuvers Monday were to raise Magellan's periapsis, or
its closest point to the planet, and then to lower its apoapsis or
most distant point from the current 528-kilometer (327-mile) distance
to 400 kilometers (245 miles). Orbit trim maneuvers to lower apoapsis
were scheduled for today, and again for April 11 and 12.
Periapsis will be stabilized at 220 kilometers (136 miles), and
those values will be held until August when the last high- resolution
gravity data will be taken, mostly over the polar regions of Venus.
|
| 456.618 | Status and info location | MTWAIN::KLAES | Keep Looking Up | Thu May 05 1994 15:39 | 84 |
| Article: 58170
From: pgf@space.mit.edu (Peter G. Ford)
Newsgroups: sci.astro
Subject: Re: Status of Magellan
Date: 5 May 1994 12:26:39 GMT
Organization: MIT Center for Space Research
In article <May.5.06.45.23.1994.18124@gandalf.rutgers.edu>
estock@gandalf.rutgers.edu (Richard G. Estock) writes:
>By return e-mail, I would greatly appreciate information on the
>current status of the Magellan spacecraft orbiting Venus as well as
>the mission itself. I seek answers to the following questions:
>
>With regard to the spacecraft,
> 1. Is it still functioning?
Yes, performing high-resolution gravity mapping and occasional
bi-static radar measurements using the telemetry transmitter.
> 2. I am aware that in January, 1992, transponder A ceased
> functioning and that transponder B was operating in a degraded
> state. What is the current state of these transponders?
Transponder B dead; Transponder A still experiencing parasitic modulations
which prevent high-bandwidth downlink modulation. Switched off and, I
believe, untested since the end of cycle 3 mapping in September 1992.
> 3. What other componentry has failed?
One of two tape recorders. One of two RAM memories in the attitude
control system. Part of the passive thermal control system, i.e. the
paintwork, which recovered somewhat after aerobraking.
>With regard to the mission,
> 4. Did JPL receive funding in fiscal 93 and 94 to continue
> operation of Magellan?
Yes, through September 1994.
> 5. Was the craft aerobraked as hoped for in 1993?
Yes.
> 6. Was the 3rd cycle of imagery completed in 1992?
Yes, just. The first cycle returned about 80% of full coverage; the
second cycle about 50%; the third about 20%. However, we did fill most
of the data gaps left by the previous cycles.
> 7. What work was slated for 93 and 94, and was the 93 work
> (4th cycle?) completed?
Since cycle 3, all regular work, except for the aerobraking period,
has been devoted to gravity mapping, i.e. synchronous up- and downlink
with the Magellan high-gain antenna (HGA) on Earth-point. There have
been two bi-static radar experiments in Oct and Nov 1993 when the
HGA was pointed to the surface and the reflected signal was received
at Earth tracking stations.
> 8. What is the current orbit and status of the spacecraft and mission?
Gravity mapping from low circular polar orbit, inclined at about 86
degrees from the Venus equator, periapsis about 212 km, apoapsis about
384 km. Next bi-static observation scheduled for early June.
>If someone could provide an e-mail address for a NASA or JPL public
>affairs official who could speak on the Magellan and other missions,
>that information would be appreciated as well. Thanks in advance.
Try newsdesk@jpl.nasa.gov, but you're better off using ftp or www
to access their on-line data directories on jplinfo.jpl.nasa.gov.
We also keep some information in the /mgn/Bulletins directory of
delcano.mit.edu. You can access our files via listserver: send e-mail
to "pds-listserver@space.mit.edu" with a single text line of "help".
Sincerely,
Dr. Peter G. Ford
Operations Manager, Geosciences Node
NASA Planetary Data System
<pgf@space.mit.edu>
|
| 456.619 | Some geological activity found on Venus | MTWAIN::KLAES | Keep Looking Up | Tue Jun 28 1994 21:02 | 193 |
| From: US4RMC::"Admin@ccmail.Jpl.Nasa.Gov" "MAIL-11 Daemon" 28-JUN-1994
To: usenet-space-news@arc.nasa.gov
CC:
Subj: JPL/Magellan finds Venus gravity hotspots
PUBLIC INFORMATION OFFICE
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIF. 91109. TELEPHONE (818) 354-5011
Contact: Jim Doyle
FOR IMMEDIATE RELEASE June 28, 1994
The planet Venus is still geologically active in places, even
though radar images of its surface indicate that little has changed in
the past half-billion years, a scientist working on data from NASA's
Magellan mission has found.
Dr. Suzanne Smrekar, a geophysicist at NASA's Jet Propulsion
Laboratory, said her studies, based on Magellan spacecraft altimetry
and gravity data, suggest that there are at least two, and possibly
more, active hot spots on Venus.
Her paper, entitled "Evidence for Active Hotspots on Venus from
Analysis of Magellan Gravity Data," is to be published later this year
in the science publication Icarus. Smrekar earlier presented her
findings before a meeting of the Lunar and Planetary Society in
Houston, Texas.
The Magellan spacecraft went into orbit around Venus in August of
1990 and, over the next two years, mapped about 98 percent of the
planet's surface with imaging radar. It then began to gather gravity
data to help scientists develop a model of the planet's interior.
Gravity is measured using only the spacecraft's radio signal.
This technique allows ground controllers to measure the spacecraft's
speed in orbit as it increases in velocity over regions of high
density or slows down over regions of lesser density.
Magellan's altimetry instrument measured the height of features
on the surface of the planet.
The gravity data showed evidence of "top loading" and "bottom
loading" at several locations, Smrekar said. Top loading is evidence
of a large mass, such as a mountain or volcano, pushing down on the
crustal plate. At hot spots, bottom loading indicates an upwelling of
less dense and, therefore, hotter material beneath the surface.
"The matter rises and is pushed upward because it is hot and,
thus, less dense," she said. "As it nears the surface, it produces
volcanism." The mechanisms are similar to those which occur on Earth
and which produce volcanoes like those on Hawaii.
Earlier data from the spacecraft's imaging radar showed that much
of the surface of Venus had been covered in the past by lava flows.
Smrekar said two regions on Venus -- Atla Regio and Bell Regio --
exhibited clear signatures of both bottom and top loading of the
elastic surface.
The signatures from the data are indicative of an active hot spot
at Atla Regio, Smrekar said. Although the loading response is less
clear, the data from Western Eistla and Beta Regio also support the
interpretation that those areas are underlain by large, hot areas,
probably due to active plumes in the mantle beneath the planet's crust.
At Bell Regio, Smrekar found indications of a late, possibly
inactive, evolutionary stage of a low-density layer that is no longer
very hot.
"These early results from a survey of four major volcanic swells
on Venus reveal hot spots in different stages of evolution," Smrekar
noted in her paper. "Analysis confirms that the Beta, Atla and
Western Eistla regions are active hot spots."
Smrekar said future studies of those areas and other possible hot
spots on Venus would continue to improve scientists' understanding of
the evolution of hot spots on both Venus and Earth.
Her work at the Jet Propulsion Laboratory was done under contract
to NASA's Office of Space Science.
#####
6/28/94 JJD
#9420
From: US4RMC::"ASTRO%GITVM1.BITNET@uga.cc.uga.edu" "Astronomy Discussion
List" 28-JUN-1994 14:53:50.23
To: Multiple recipients of list ASTRO <ASTRO%GITVM1.BITNET@uga.cc.uga.edu>
CC:
Subj: Venus Geologically Active, Magellan Finds
Donald Savage
Headquarters, Washington, D.C.
June 28, 1994
(Phone: 202/358-1547)
Jim Doyle
Jet Propulsion Laboratory, Pasadena, Calif.
(Phone: 818/354-5011)
RELEASE: 94-105
VENUS STILL GEOLOGICALLY ACTIVE, MAGELLAN FINDS
The planet Venus is still geologically active in places, even
though radar images of its surface indicate that little has changed in
the past half-billion years, a scientist working on data from NASA's
Magellan mission has found.
Dr. Suzanne Smrekar, a geophysicist at NASA's Jet Propulsion
Laboratory (JPL), Pasadena, Calif., said her studies, based on
Magellan spacecraft altimetry and gravity data, suggest that there are
at least two, and possibly more, active hot spots on Venus.
Her paper, entitled "Evidence for Active Hotspots on Venus
from Analysis of Magellan Gravity Data," is to be published later this
year in the science publication, Icarus. Smrekar earlier presented
her findings before a meeting of the Lunar and Planetary Science
conference in Houston, Texas.
The Magellan spacecraft went into orbit around Venus in August
of 1990 and over the next two years mapped about 98 percent of the
planet's surface with imaging radar. It then began to gather gravity
data to help scientists develop a model of the planet's interior.
Gravity is measured using only the spacecraft's radio signal.
This technique allows ground controllers to measure the spacecraft's
speed in orbit as it increases in velocity over regions of high
density or slows down over regions of lesser density. Magellan's
altimetry instrument measured the height of features on the surface of
the planet.
The gravity data showed evidence of "top loading" and "bottom
loading" at several locations, Smrekar said. Top loading is evidence
of a large mass, such as a mountain or volcano, pushing down on the
crustal plate. At hot spots, bottom loading indicates an upwelling of
less dense and, therefore, hotter material beneath the surface.
"The matter rises and is pushed upward because it is hot and
thus less dense," she said. "As it nears the surface, it produces
volcanism." The mechanisms are similar to those which occur on Earth
and which produce volcanoes like those on Hawaii.
Earlier data from the spacecraft's imaging radar showed that
much of the surface of Venus had been covered in the past by lava flows.
Smrekar said two regions on Venus -- Atla Regio and Bell Regio
-- exhibited clear signatures of both bottom and top loading of the
elastic surface.
The signatures from the data are indicative of an active hot
spot at Atla Regio, Smrekar said. Although the loading response is
less clear, the data from Western Eistla and Beta Regio also support
the interpretation that those areas are underlain by large, hot areas,
probably due to active plumes in the mantle beneath the planet's crust.
At Bell Regio, Smrekar found indications of a late, possibly
inactive, evolutionary stage of a low-density layer that is no longer
very hot.
"These early results from a survey of four major volcanic
swells on Venus reveal hot spots in different stages of evolution,"
Smrekar noted in her paper. "Analysis confirms that the Beta, Atla
and Western Eistla regions are active hot spots."
Smrekar said future studies of those areas and other possible
hot spots on Venus would continue to improve scientists' understanding
of the evolution of hot spots on both Venus and Earth.
Her work at JPL was done under contract to NASA's Office of
Space Science, Washington, D.C.
- end -
NOTE TO EDITORS : A four-part image depicting gravity results at
Venus is available by faxing your request to the Headquarters
Broadcast and Imaging Branch on 202/358-4333. The photo numbers are:
B & W: 94-H-179; Color: 94-HC-167.
% ====== Internet headers and postmarks (see DECWRL::GATEWAY.DOC) ======
% Date: Tue, 28 Jun 1994 18:15:34 +0000
% Reply-To: Astronomy Discussion List <ASTRO%GITVM1.BITNET@uga.cc.uga.edu>
% Sender: Astronomy Discussion List <ASTRO%GITVM1.BITNET@uga.cc.uga.edu>
% From: Ron Baalke <BAALKE@KELVIN.JPL.NASA.GOV>
% Subject: Venus Geologically Active, Magellan Finds
% X-To: astro@gitvm1.bitnet
% To: Multiple recipients of list ASTRO <ASTRO%GITVM1.BITNET@uga.cc.uga.edu>
|
| 456.620 | July 1 | MTWAIN::KLAES | Houston, Tranquility Base here... | Fri Jul 01 1994 16:52 | 41 |
| From: US4RMC::"Admin@ccmail.Jpl.Nasa.Gov" "MAIL-11 Daemon" 30-JUN-1994
To: usenet-space-news@arc.nasa.gov
CC:
Subj: Magellan status 7/1/94
PUBLIC INFORMATION OFFICE
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIF. 91109. TELEPHONE (818) 354-5011
MAGELLAN STATUS REPORT
July 1, 1994
The Magellan mission at Venus, in its sixth 243-day cycle,
continues gravity mapping of the planet. The spacecraft is
healthy, and controllers are putting it behind the antenna every
other orbit to shade it and maintain thermal control.
On July 5, controllers will recondition the batteries, a
routine process that requires commands for the spacecraft to
discharge each of the two batteries and then recharge them. On
July 15, Magellan will perform a radio occultation experiment,
sending signals through Venus' atmosphere to Earth.
Magellan has been collecting high-resolution gravity data
from near-circular orbit since early August 1993. Its fifth
orbital cycle ended April 17, 1994 at which time about 70 percent
of Venus was covered. It is predicted that 95 percent of gravity
coverage will have been acquired when the mission ends this fall.
The mission is to end in October when the spacecraft will be
sent into the atmosphere. The project will use the spacecraft
capability to get the greatest science return with a "windmill
experiment" to study the dynamic forces on the spacecraft.
Controllers will collect data as the atmosphere exerts pressure
on the solar panels, turning the spacecraft on its axis. Since
the spacecraft is not designed to operate unattended for more
than a few weeks, it will be sent into the atmosphere and dragged
down where it will burn up in its descent.
|
| 456.621 | August 1 | MTWAIN::KLAES | Houston, Tranquility Base here... | Mon Aug 01 1994 20:06 | 32 |
| From: US4RMC::"Admin@ccmail.Jpl.Nasa.Gov" "MAIL-11 Daemon" 30-JUL-1994
To: usenet-space-news@arc.nasa.gov
CC:
Subj: Magellan status 8/1/94
PUBLIC INFORMATION OFFICE
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIF. 91109. TELEPHONE (818) 354-5011
MAGELLAN MISSION STATUS
August 1, 1994
Controllers of the Magellan mission at Venus have final plans
for the end of mission strategy. Magellan will complete tracking
activities through early October to fill out the high-resolution
Venus gravity map. Then the project will begin a "windmill" experiment
before beginning a termination experiment; both are designed to gain
additional aerodynamic and atmospheric data for future mission designs.
The windmill experiments will be conducted September 6 through 9.
The experiment will apply a torque to the spacecraft in the upper
atmosphere to gather aerodynamic data as it spins slowly on its axis.
The termination experiment will be performed at three lower
altitudes to gather data similar to the windmill experiment. In the
final phase, the spacecraft's altitude will be lowered starting
October 10 and it will crash to the surface by October 14.
#####
|
| 456.622 | The Last Days of Magellan | MTWAIN::KLAES | No Guts, No Galaxy | Wed Aug 03 1994 16:07 | 136 |
| From: US4RMC::"reptile@kaiwan.com" "Tecumseh" 3-AUG-1994 01:58:57.69
To: usenet-space-news@arc.nasa.gov
CC:
Subj: Magellan final LOS
This memo summarizes the decisions made at the 7/13, 7/20, and 7/27
Magellan Mission Planning Meetings defining the remaining planned
activities in the Magellan Mission. This plan is final and no changes
will be made except those needed to correct problems found during
implementation.
In the next 2 1/2 months, the Magellan project plans to accomplish the
following:
Complete the third and final Radio Occultation Experiment.
Perform Orbit Trim Maneuvers (OTMs) to lower Periapsis to improve
Atmospheric Science Data.
Perform a Windmill Experiment to study the gas/surface interactions
of the spacecraft solar panels with the upper atmosphere of Venus.
Perform a Termination Experiment to study the deepest possible
levels of the Venus atmosphere. This will result in the destruction
of the spacecraft within several days of initiating the experiment.
There are four sequences remaining in the Magellan Mission: H4216,
H4237, H4258, and Termination. the activities planned for each of these
is described below.
H4216
The sequence begins Thursday, August 4. Gravity science data will be
collected every day of this sequence. On Tuesday, August 9, the final
Radio Occultation Experiment will be performed. The spacecraft will
execute Limb Track Maneuvers throughout each of five orbit occultations.
The data will be collected in Spain at DSS 61.
H4237
The sequence begins Thursday, August 25, with two OTMs of about 9 km
each. The OTMs will be performed on successive orbits to lower
periapsis to improve atmospheric science data. Gravity science data
will be collected every day of this sequence. On Tuesday, August 30, a
preliminary windmill test will be performed to determine the magnitude
of atmospheric torques applied to the spacecraft. The Windmill
Experiment will be performed between Tuesday, September 6, and Friday,
September 9, with Monday and Tuesday September 12 and 13 held as
contingency experiment days.
The Windmill Experiment will have the High Gain Antenna pointed to Earth
such that the Solar Panel axis is at right angles to the velocity vector
at periapsis. The Solar Panels will then be set to eight different sets
of opposing angles. The resulting torques applied to the spacecraft will
be sensed as increased speed in the onboard reaction wheels. This torque
data will be used to determine the lift and drag characteristics of the
Solar Panels at different angles of attack. The momentum accomodation
coefficient will be determined from the lift and drag data. The results
of this experiment will help refine models used to plan and design future
aerobraking missions.
H4258
The sequence begins Thursday, September 15. Two OTMs of about 9 km each
will be performed on successive orbits on Wednesday, September 28 to
lower periapsis to improve atmospheric science data. Gravity science
data will be collected every day of this sequence.
Termination
The termination phase is not a sequence. It begins on Monday, October
10, by cancelling the previous sequence and changing the High Gain
Antenna (HGA) earthpoint orientation to a special Medium Gain Antenna
(MGA) earthpoint orientation. Three OTMs of just under 9 km will then
be performed with one pause orbit between each. On Tuesday morning,
October 11, a single OTM of just under 9 km will be performed. On
Wednesday morning, October 12, a final OTM of just under 9 km will be
performed. All Termination OTMs will be performed to lower periapsis.
The spacecraft will operate on thruster control without a sequence and
with most fault protection disabled. No star calibrations or reaction
wheel desaturations will be performed. The special MGA earthpoint
attitude will be designed such that the MGA boresight will point at
Earth and the Solar Panel axis will be at right angles to the velocity
vector at periapsis. The Solar Panels will be rotated in opposing
directions to induce a torque on the spacecraft during passage through
the atmosphere. One set of opposing Solar Panel angles will be used at
all times from the start of Termination through the demise of the spacecraft.
Atmospheric science will be accomplished by estimating the atmospheric
drag on the spacecraft as well as the time, direction, and magnitude of
spacecraft control thrusters while the spacecraft is in the atmosphere.
The thrusters will be attempting to counteract the aerodynamic torques
induced by the atmosphere acting on the Solar Panels and the High Gain
Antenna. From calculated torques, spacecraft aerodynamic coefficients
can be derived. This data will be collected in five altitude regimes
for at least two orbits in each regime. The altitude regimes are in the
following ranges (approximate):
Date Altitude Range (km) Number of Orbits
10/10 173 km 2
164 km 2
10/10 to 10/11 155 to 154 km 15
10/11 to 10/12 146 to 145 km 15
10/12 to 10/13 136 to 131 km 15
The spacecraft will enter the atmosphere permanently within a few hours
after the periapsis altitude drops below 135 km. It is unlikely that
the actual demise of the spacecraft will be witnessed on the ground due
to loss of communication with Earth. The cause of this will be the
spacecraft's inability to point the MGA to Earth. This might happen in
several ways: The natural drift in attitude knowledge may be sufficient
to take the MGA off angle enough to lose telemetry and signal; or the
aerodynamic torques may cause the spacecraft to rotate fast enough for
attitude knowledge to be lost; or the thruster control while in the
atmosphere might consume all of the remaining fuel causing the
spacecraft to be unable to point the MGA to Earth. It is not known how
long communication with the spacecraft can be maintained. It is hoped
that telemetry can be collected at least through all planned OTMs and a
few orbits after the final OTM. There is a reasonable probability that
communications with Earth will be lost at any time after the third OTM
on October 10 due to unforseen component failures or unknown adverse
interactions with the atmosphere. In such a case, no heroic measures
will be taken to recover the spacecraft.
--
The above opinions were formed while under the | ___ |
influence of mind-expanding drugs. |___/ooo\___|
reptile@kaiwan.com -======((*))=( .o. )=((*))======-
^^^^^
|
| 456.623 | August 26 | MTWAIN::KLAES | No Guts, No Galaxy | Wed Aug 31 1994 16:37 | 51 |
| From: US1RMC::"Admin@ccmail.Jpl.Nasa.Gov" "MAIL-11 Daemon" 29-AUG-1994
To: usenet-space-news@arc.nasa.gov
CC:
Subj: Magellan status 8/26/94
PUBLIC INFORMATION OFFICE
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIF. 91109. TELEPHONE (818) 354-5011
MAGELLAN MISSION STATUS
August 26, 1994
Controllers of the Magellan mission at Venus started final
mission activities Thursday with two orbit trim maneuvers. The
maneuvers lowered the altitude of periapsis (the closest approach to
the planet) from 200 kilometers to 182 kilometers (124 miles to 113
miles). That activity began the setup stages for the "windmill"
experiment planned for Sept. 6-9, and the final "termination"
experiment activities planned for Oct. 10-14. Magellan's final
gravity data acquisition continues successfully and will conclude on
Oct. 9. The "windmill" and "termination" experiments will gain
additional aerodynamic and atmospheric data for future mission designs.
Controllers are also managing the spacecraft power as the solar
array performance continues to degrade. The loss of power appears to
result from thermal fatigue caused by the many solar occultation
periods during the past year. As it went in and out of sunlight,
depending on the planet's position relative to the sun, the frequent
changes from high to low temperature and back again caused some of the
solar cells to fail. The loss of solar cells was expected as the
spacecraft neared the end of its operational lifetime. The solar
cycles and effect on solar cell strings have exceeded previous
lifetime estimates. In many areas the spacecraft design life was two
to three years and Magellan has operated for more than five years.
Controllers are hopeful the power situation can be managed
through mid-October, but it is apparent that the Magellan spacecraft
is close to the end of its useful life. Beginning on Sept. 6, the
"windmill" experiment will reconfigure the solar panels to see how
much torque is applied by Venus' very thin upper atmosphere.
Controllers will see how much control torque they have to apply to
prevent the spacecraft from spinning on its axis.
The "termination" experiment will be performed at three lower
altitudes to gather data similar to the "windmill" experiment. In the
final phase, the spacecraft's altitude will be lowered starting on
Oct. 10. The spacecraft is expected to burn up in Venus' atmosphere
by Oct. 14.
|
| 456.624 | Windmill experiment begins | MTWAIN::KLAES | No Guts, No Galaxy | Thu Sep 08 1994 20:20 | 140 |
| From: US1RMC::"DHILL@pao.hq.nasa.gov" "HILL, DIANNE" 8-SEP-1994 09:47:15.03
To: "press-release@hq.nasa.gov" <press-release@hq.nasa.gov>
CC:
Subj: 94-147 MAGELLAN EXECUTES 'WINDMILL' EXPERIMENT AS MISSION DRAWS NEAR
Douglas Isbell
Headquarters, Washington, D.C.
September 7, 1994
(Phone: 202/358-1753)
Jim Doyle
Jet Propulsion Laboratory, Pasadena, Calif.
(Phone: 818/354-5011)
RELEASE: 94-147
MAGELLAN EXECUTES 'WINDMILL' EXPERIMENT AS MISSION END DRAWS NEAR
NASA Magellan probe yesterday began a unique experiment
designed to return data about the upper atmosphere of Venus and the
behavior of a spacecraft entering it. The experiment marks the
beginning of final activities for the spacecraft, which is expected to
burn up in the atmosphere of Venus by October 14.
"This is the next to last act of a truly magnificent
performance by Magellan and its science and operations teams," said
Dr. Wesley T. Huntress, Associate Administrator for Space Science at
NASA Headquarters, Washington, D.C. "Magellan has far surpassed all of
its original mission goals and, in the process, revolutionized our
understanding of a planet that represents what Earth might
be like with a runaway greenhouse effect."
With its primary mission of mapping the surface of Venus
successfully accomplished, Magellan has been used for a series of
experiments that were unanticipated before its launch. In the latest
maneuver, known as the "windmill" experiment, the spacecraft's
wing-like solar arrays are turned in opposite directions, like
windmill sails, to encounter pressure from molecules in the upper
atmosphere of Venus.
The experiment is measuring how much torque will be needed to
keep the spacecraft from spinning on its axis, said Project Manager
Doug Griffith at NASA's Jet Propulsion Laboratory (JPL), Pasadena,
Calif. These data will allow engineers and scientists to better
understand basic gas-surface interactions and to gain additional
aerodynamic and atmospheric data on Venus for future mission designs.
The windmill experiment is scheduled to last until September 14.
Two weeks later, more orbit trim maneuvers are scheduled to lower the
spacecraft's altitude to prepare for the final termination experiment.
Three further trim maneuvers will change the altitude by 5 to 6 miles
(8 to 9 kilometers) each on October 10, placing the altitude of
periapsis --or closest approach to the planet -- at 96 miles (155
kilometers). The spacecraft's orbit will be lowered finally to 85
miles (136 kilometers) on October 12, with Magellan again put in a
windmill attitude to collect more atmospheric data during its final
entry. Gravity data acquisition will continue during all these
periods up until October 10.
"After October 12, Magellan will permanently enter the atmosphere
in about two days, possibly in one day," Griffith said. The
atmosphere will drag the spacecraft toward the surface of the planet,
but it will burn up high in the skies over Venus, he said.
There are two primary possibilities leading to NASA's final
loss of contact with Magellan, Griffith said. Either the spacecraft
will overheat and its communications systems will be damaged, or
Magellanes control thrusters will be unable to maintain pointing
control toward ground-based receiving dishes on Earth as the
spacecraft spins to its demise.
In recent weeks, the performance of the spacecraft's solar arrays
has begun to degrade due to the extreme temperature changes as the
spacecraft passes from direct sunlight to shadow during its orbit.
The thermal stress after more than five years in space and several
weeks in low orbit has caused degeneration of its solar cell
connections and has brought the spacecraft near the end of its useful
life, Griffith said.
"It is a race to the finish," said Betsy Beyer, Magellan
Program Manager at NASA Headquarters. With the continuing loss of
power due to the solar cell degeneration, the spacecraft may shut down
even earlier than projected, before a planned entry experiment.
"Magellan has done more than its duty," Beyer said. "If it goes in
its own way, instead of how we planned to end it, it is still a winner."
Controllers sent commands to Magellan in late August for orbital
trim maneuvers that reduced its altitude from a near-circular orbit of
123 by 338 miles (197 by 541 kilometers) to an orbit of 107 by 242
miles (172 by 390 kilometers). These altitude reductions were
required to set up conditions for the final experiment phases.
Magellan was launched in May 1989, and began mapping the
surface of the planet using synthetic aperture--or side-looking--radar
in September 1990. In three cycles, each comprising one Venus day or
243 Earth days, the spacecraft mapped 98 percent of the planet's
surface, providing unprecedented views of its unique pancake domes of
lava, strange volcanic structures, craters and high mountains.
In three subsequent cycles, it has measured Venusian gravity over
95 percent of the planet, gathering data so that scientists can map
the planet's interior. Magellan also has contributed to ongoing study
of the planetes massive atmosphere of carbon dioxide and high sulfuric
acid clouds. This period included the first-ever "aerobraking" of a
spacecraft into a near-circular planetary orbit, for Magellanes final
operations.
The data which have streamed back from Magellanes radar imager,
its atmospheric studies and its gravity data acquisition maneuvers
have built a vast data base of new knowledge about Venus and the
formation of the Solar System that will be studied by scientists for
decades to come, project officials said.
JPL manages the Magellan project for NASA's Office of Space
Science, Washington, D.C.
- end -
NOTE TO EDITORS: To illustrate this story, a variety of
computer-enhanced, false-color images of Venus taken by Magellan is
available to news media by faxing your request to the NASA
Headquarters Broadcast and Imaging Branch on 202/358-4333.
NASA press releases and other information are available
automatically by sending an Internet electronic mail message to
domo@hq.nasa.gov. In the body of the message (not the subject line)
users should type the words, "subscribe press release" (no quotes).
The system will reply with a confirmation via E-mail of each
subscription. A second automatic message will include additional
information on the service.
% ====== Internet headers and postmarks (see DECWRL::GATEWAY.DOC) ======
% From: "HILL, DIANNE" <DHILL@pao.hq.nasa.gov>
% To: "press-release@hq.nasa.gov" <press-release@hq.nasa.gov>
% Subject: 94-147 MAGELLAN EXECUTES 'WINDMILL' EXPERIMENT AS MISSION DRAWS NEAR
% Date: Wed, 07 Sep 94 16:14:00 PDT
% Message-Id: <2E6E497E@ms.hq.nasa.gov>
% Sender: press-release-Owner@hq.nasa.gov
|
| 456.625 | Preparing for the end | MTWAIN::KLAES | No Guts, No Galaxy | Wed Sep 14 1994 20:27 | 176 |
| From: US1RMC::"baalke@kelvin.jpl.nasa.gov" "Ron Baalke" 13-SEP-1994
To: usenet-space-news@arc.nasa.gov
CC:
Subj: Magellan Begins Termination Activities
From the "JPL Universe"
September 9, 1994
Magellan begins termination activities
JPL's Magellan spacecraft on Sept. 6 began a "windmill"
experiment, testing the amount of pressure needed to keep it from
spinning in Venus's upper atmosphere. The experiment begins the
final termination activities for the spacecraft, expected to burn
up by Oct. 14.
Magellan was launched in May 1989 and began mapping the surface
of the planet in September 1990. In three cycles, each comprised
of one Venus day or 243 Earth days, it mapped with imaging radar
98 percent of the planet's surface.
In three subsequent cycles, it has observed Venus' gravity over
95 percent of the planet, gathering data so scientists can map the
planet's interior. This period also included the "aerobraking" of
the spacecraft into a near-circular orbit for final gravity
operations in the last two cycles.
In recent weeks, the spacecraft's solar arrays have experienced
losses due the extremes of temperature as the spacecraft went from
direct sunlight to shadow in its orbit. The thermal stress after
more than five years in space has caused degeneration of solar
cells and has brought the spacecraft near the end of its useful
life, said Project Manager Doug Griffith.
Controllers sent commands in late August to begin orbit trim
maneuvers to reduce the altitude of the spacecraft from a near-
circular orbit of 197 km by 541 km (123 by 338 miles) to an orbit
of 172 km by 390 km (107 by 242 miles). These altitude reductions
were required to setup conditions for the final experiment phases.
For the "windmill" experiment, the spacecraft's wing-like solar
arrays are turned in opposite directions, like windmill sails, to
receive pressure of upper atmosphere molecules. The experiment is
testing to see how much torque will be needed to keep the
spacecraft from spinning on its axis, Griffith said. These data
will allow engineers and scientists to better understand gas-
surface interactions and gain additional aerodynamic and
atmospheric data for future mission design.
The windmill experiment is scheduled to last until Sept. 14.
Two weeks later, more orbit trim maneuvers are scheduled to lower
the spacecraft altitude to prepare for the final termination experiment.
Three further trim maneuvers will change the altitude by 8 to 9
km (5 to 6 miles) each on Oct. 10, which will place the altitude
of periapsis at 155 km (96 miles). It will be lowered finally to
136 km (85 miles) on Oct. 12. Gravity data acquisition will
continue during all these periods up until Oct. 10.
"After Oct. 12, Magellan will permanently enter the atmosphere
in about two days, possibly in one day," Griffith said. The
atmosphere will drag the spacecraft toward the surface of the
planet, but it will burn up high in the skies over Venus, he added.
Two things may happen, Griffith explained. The spacecraft will
overheat, or its control thrusters will be unable to maintain
pointing control. In either circumstance, project controllers will
lose communication with Magellan.
Using synthetic aperture radar, or side-looking radar, the
Magellan project has mapped almost all of the surface of Venus at
high resolution, providing maps of its unique pancake domes of
lava, strange volcanic structures, craters and high mountains.
Additionally, the project has provided a gravity map of the
planet and contributed to an ongoing study of its massive
atmosphere of carbon dioxide and high sulfuric acid clouds.
The data that streamed back from its radar image and gravity-
data acquisition during six cycles has built a gigantic database
of new knowledge about Venus and the formation of the solar system
which will be studied by scientists for decades to come, project
officials said.
__________________________________________________________________
Magellan coming to the end of a long and productive life
Magellan will end its mission operations in mid-October, when the
spacecraft enters the atmosphere of Venus and burns up. The
mission has far exceeded all of its primary and extended-mission
objectives and has produced more image data than all previous U.S.
planetary missions combined.
By Phil Allin, Magellan Project
In recent months it appeared that Magellan might become the first
functioning planetary spacecraft to be abandoned in space. Due to
the failure of the on-board tape recorder "A" and the subcarrier
modulation of transmitter A, and the degraded performance of
transmitter B, Magellan is incapable of resuming radar mapping.
But Magellan is not "dead." It continues to maintain precise
attitude control and a strong carrier signal for communication
with Earth.
It has been returning global gravity data from circular orbit
since early August 1993 and will complete a high-resolution
gravity map covering 95 percent of Venus on Oct. 9. Then it will
be commanded to lower its orbit in a series of steps that will
cause it to enter the atmosphere. Thus it may become the first
planetary spacecraft to be terminated intentionally.
On other planetary missions the spacecraft usually quit
operating due to the failure of a critical system or the depletion
of some limited resource such as attitude-control propellant.
For example, when Mariner 2 went to Venus in 1962, several of
the critical components became hotter than their design limits.
When it went silent about a month after the successful flyby, it
was believed that the battery or earth sensor had failed. Many of
the later Mariners failed when they ran out of the nitrogen gas
used for attitude control.
When the Pioneer Venus Orbiter ran out of propellant in October
1992 after 14 years in space, controllers could not raise the periapsis
out of the Venus upper atmosphere and it burned up as it entered.
Some planetary spacecraft have been designed for long,
quiescent cruise periods, maintaining a fixed attitude with
reference to the Earth and reference stars. In this way, Voyagers
1 and 2 can continue their search for the heliopause while
expending very little propellant. The demise of the Voyagers is
expected to come when the output from the radioisotope
thermoelectric generators (RTGs) is insufficient to power the
critical on-board electronics--in 20 to 30 years.
Magellan is a different kind of bird. Due to the almost
constant maneuvers required during the radar-mapping phase of the
mission, the spacecraft is controlled by reaction wheels. These
electrically driven momentum wheels allow for smooth movement in
each of the three axes. This system requires frequent "desaturations"
(adjustment of spin rate in the wheels) and "starcals" (verification
of the attitude by scanning reference stars).
During brief periods in which the forces on the spacecraft
might exceed the control of the reaction wheels--such as the Venus
orbit insertion or the recent aerobraking passes--the spacecraft is
switched to thruster control. The thrusters are also used during
desaturations, but Magellan carries far too little propellant to
remain on thrusters for an extended period.
Perhaps the greatest risk to Magellan is the failure of one of
the remaining gyros. Gyro A2 is presently at 52,000 hours of
operating life. The gyros are designed to have an operating
lifetime between 40,000 and 60,000 hours. However, gyro B2 failed
with less than 20,000 hours. If either of the remaining gyros
fail, the spacecraft would be unable to maintain its attitude in
space and would tumble out of control.
Another threat is the degradation of the solar panels. Magellan
is in a period of solar occultation, passing through the shadow of
Venus on each orbit.
Fifteen times a day the panels are subjected to a 190 C
temperature cycle. As a result, the electrical connections between
the solar cells are breaking, reducing the power output. The
power has to be managed by periodically turning off some of the
spacecraft electronics.
Analysis of the present propellant reserves show that, even if
all the remaining propellant were used to raise the orbit, the
spacecraft will enter and burn up in the Venus atmosphere in about
five years.
###
|
| 456.626 | September 16 | MTWAIN::KLAES | No Guts, No Galaxy | Fri Sep 16 1994 19:40 | 36 |
| From: US3RMC::"Admin@ccmail.Jpl.Nasa.Gov" "MAIL-11 Daemon" 16-SEP-1994
To: usenet-space-news@arc.nasa.gov
CC:
Subj: Magellan status 9/16/94
PUBLIC INFORMATION OFFICE
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIF. 91109. TELEPHONE (818) 354-5011
MAGELLAN STATUS REPORT
September 16, 1994
NASA's Magellan spacecraft on September 14 successfully
finished a unique seven-day "windmill" experiment to study basic
oxygen gas-surface interaction by dipping the spacecraft into the
upper rarified atmosphere of Venus. The spacecraft's winglike
solar arrays were turned in opposite directions -- like windmill
sails -- and the atmospheric forces on the spacecraft were measured.
The experiment allowed lift, drag, and atomic oxygen gas-
surface values to be measured for the first time in a controlled
free-molecular gas flow experiment. Mission controllers at the
Jet Propulsion Laboratory said the measurements will help
engineers understand the atmospheric forces on Earth-orbiting
satellites and will aid in aerobraking designs for future
planetary spacecraft missions.
The project team is now concentrating on continued Venus
gravity mapping activities through October 9; and the final
termination experiment is to be performed October 10 when the
spacecraft will be lowered deeper into the atmosphere. The
spacecraft is expected to burn up in the upper atmosphere of
the planet by October 14.
|
| 456.627 | Magellan status 9/30/94 | 56821::BATTERSBY | | Sat Oct 01 1994 12:42 | 53 |
| Article: 6500
From: Admin@ccmail.jpl.nasa.gov
Newsgroups: sci.space.news
Subject: Magellan status 10/1/94
Date: 30 Sep 1994 20:56:00 -0700
Organization: Jet Propulsion Laboratory - Pasadena CA
Sender: daemon@news.arc.nasa.gov
PUBLIC INFORMATION OFFICE
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIF. 91109. TELEPHONE (818) 354-5011
MAGELLAN MISSION STATUS
October 1, 1994
The Magellan spacecraft is performing acceptably with less
than two weeks left in its mission. There has been some further
minor degradation of the solar panels, but that is offset by
decreasing changes from sunlight to shade and the resulting wide
variations in temperature.
The termination phase of the mission will begin Tuesday,
October 11, on orbit number 15,018. The spacecraft's
communication will be switched from the high-gain antenna to the
medium-gain antenna, and all control from that point will be in
real-time commands.
Magellan will perform orbit-trim maneuvers on each of the
next four orbits to quickly lower the periapsis, the closest
point to the planet, to 150 kilometers (93 miles). That will
enable the gathering of aerodynamic data in the sparsely explored
regions of the upper atmosphere. An optional fifth trim maneuver
may be performed if needed to lower periapsis to the desired
altitude.
It is predicted that communication with the spacecraft will
be lost within a few orbits due to depletion of the batteries or
attitude control propellant. Magellan may go silent by the
evening of October 11, perhaps on or before orbit number 15,025,
or it may last a day or two.
As with satellites entering Earth's atmosphere, it is
difficult to predict exactly when Magellan will enter Venus's
atmosphere. But the spacecraft will be traveling more than 7
kilometers per second (15,658 miles per hour) and will
disintegrate from a rapid combination of dynamic force and heat.
It is possible that a few pieces, such as the inner hubs of the
reaction wheels, may reach the surface as burned cinders lost
among the vast lava flows which Magellan revealed.
#####
|
| 456.628 | Magellan Final Briefing.... | 56821::BATTERSBY | | Thu Oct 06 1994 13:28 | 63 |
| Article: 6521
From: Admin@ccmail.jpl.nasa.gov
Newsgroups: sci.space.news
Subject: JPL/Magellan finale press briefing
Date: 5 Oct 1994 07:20:10 -0700
Organization: Jet Propulsion Laboratory - Pasadena CA
Sender: daemon@news.arc.nasa.gov
PUBLIC INFORMATION OFFICE
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIF. 91109. TELEPHONE (818) 354-5011
Contact: Jim Doyle
NOTE TO EDITORS AND NEWS DIRECTORS October 4, 1994
The Magellan spacecraft's dramatic plunge into the
atmosphere of Venus next week will be the topic of a NASA press
briefing Thursday, Oct. 6.
The briefing, which begins at 10:30 a.m. Pacific time, will
be held in von Karman Auditorium at the Jet Propulsion
Laboratory, 4800 Oak Grove Drive, Pasadena. The event will be
carried live on NASA Television, with two-way question-and-answer
capability from other NASA centers.
Magellan will cap its five-year mission radar-mapping Venus
on Oct. 11 when flight controllers command the spacecraft to dive
into the planet's dense atmosphere. Most of the spacecraft is
expected to burn up in the atmosphere within a day, although some
pieces will probably reach the planet's surface. Scientists are
interested in what the experiment will tell them about Venus'
atmosphere, while engineers will benefit from data on the
spacecraft's performance as it descends.
Launched in May 1989, Magellan went into orbit at Venus in
August 1990. It has since mapped 98 percent of the planet's
surface and collected comprehensive maps of Venus' gravity field.
Speakers at Thursday's briefing will be Dr. Wesley T.
Huntress Jr., associate administrator, Office of Space Science,
NASA Headquarters, Washington, D.C.; Dr. Moustafa T. Chahine, JPL
chief scientist; Douglas G. Griffith, Magellan project manager,
JPL; Dr. R. Stephen Saunders, Magellan project scientist, JPL;
and Prof. Robert Tolson, George Washington University. Three
images, including a gravity map of the planet, will be released
at the briefing.
The latest updates on Magellan's status -- as well as a
comprehensive gallery of images and information from the five-
year mission -- will be available to the public beginning Oct. 6
at JPL's electronic access site. This may be accessed via
Internet by the World Wide Web system from JPL's home page at the
address http://www.jpl.nasa.gov; by anonymous file transfer
protocol (ftp) to jplinfo.jpl.nasa.gov; or by dialup modem to
(818) 354-1333.
NASA Television may accessed through GTE Spacenet 2,
transponder 5, frequency 3880 Mhz, 69 degrees west longitude.
#####
|
| 456.629 | Requiem | SKYLAB::FISHER | Indecision is the key to flexibility! | Wed Oct 12 1994 12:01 | 8 |
| Magellan was scheduled to lower its orbit yesterday. My news feed is dead for
the moment, so I have not seen any results. There is nothing new at the
Magellan WWW site since announcing yesterday that they were going to do it.
However, I assume the deed is done, and the signals have stopped.
I feel sad.
Burns
|
| 456.630 | Nothing seen in newsgroups as of this morning... | 56821::BATTERSBY | | Wed Oct 12 1994 12:39 | 15 |
| I just finished cruising through my USENET news feed and didn't
see anything posted later than 9/29/94 on the Magellan status.
I looked in the following newsgroups. I haven't looked at the
WWW Magellan home page yet.
looked in;
sci.space.news
sci.space.science
sci.space.tech
sci.space.shuttle
I'm sure something will be posted today or in the next day or so.
I'll look again during lunch today.
Bob
|
| 456.631 | | HELIX::MAIEWSKI | | Wed Oct 12 1994 12:56 | 6 |
|
Magellan is actually getting pretty good press coverage. NBC News and
Boston's WBZ News who are both notorious for misunderstanding and bashing the
space program both gave positive stories.
George
|
| 456.632 | Nothing new seen on JPL's WWW server either... | 56821::BATTERSBY | | Wed Oct 12 1994 13:22 | 4 |
| No new updates on Magellan status on JPL's home page under
"new flashes" yet.
Bob
|
| 456.633 | About 5 seconds of coverage | ROGER::GAUDET | Because the Earth is 2/3 water | Wed Oct 12 1994 14:44 | 4 |
| Peter Jennings briefly mentioned "the demise of Magellan" toward the end of last
night's nightly news. I guess something is better than nothing.
...Roger...
|
| 456.634 | | STAR::HUGHES | Captain Slog | Wed Oct 12 1994 15:14 | 4 |
| According to the Beeb this morning, Magellan was expected to enter the
Venusian atmosphere today, fwiw.
gary
|
| 456.635 | From JPL (via the Web)... | PRAGMA::GRIFFIN | Dave Griffin | Wed Oct 12 1994 19:03 | 24 |
| Magellan is Gone
Loss of Signal Occurred at 3:04 AM PDT Today
NASA's Magellan spacecraft will make a dramatic conclusion to its highly successful mission
at Venus when it is commanded to plunge into the planet's dense atmosphere Tuesday,
October 11, 1994. During its four years in orbit around Earth's sister planet, the spacecraft has
radar-mapped 98 percent of the surface and collected high-resolution gravity data of Venus.
The purpose of the crash landing is to gain data on the planet's atmosphere and on the
performance of the spacecraft as it descends.
Up-to-date status reports will be available from this page, which also offers Venus images
and other highlights from the mission.
http://NewProducts.jpl.nasa.gov:80/magellan/
Sniff!
- dave
|
| 456.636 | | PRAGMA::GRIFFIN | Dave Griffin | Wed Oct 12 1994 19:06 | 4 |
| If you have Mosaic, check out the graphics on the aforementioned page and
the status page (which has a rather humorous one...)
|
| 456.637 | Magellan Final Report - 10/12/94 | 56821::BATTERSBY | | Wed Oct 12 1994 20:22 | 79 |
| Here's the final status report posted on the Status page of the WWW
page http://NewProducts.jpl.nasa.gov:80/magellan/
I had to recompose this report as it wouldn't fit on a 80 column
screen.
Bob
-----------------------------------------------------------------------
Magellan Status Report - October 12, 1994
PUBLIC INFORMATION OFFICE
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIF. 91109. TELEPHONE (818) 354-5011
Contact: Jim Doyle
MAGELLAN STATUS REPORT
FOR IMMEDIATE RELEASE October 12, 1994
The successful five-and-a-half-year mission of NASA's Magellan spacecraft to
map the surface and measure the gravity of Venus ended today when ground
controllers lost contact with the spacecraft. Magellan is expected
to burn up in the planet's upper atmosphere within two days.
The final chapter of the Magellan story was written as Earth-based tracking
stations lost the spacecraft's radio signal at 10:02 Universal Time (3:02 a.m.
Pacific Daylight Time). The loss of signal, which was anticipated, was
due to low power on the spacecraft, exacerbated by Magellan's orientation as
it performed a final experiment in the upper atmosphere of Venus.
The spacecraft's thrusters were fired in four sequences on Tuesday, Oct. 11,
to lower Magellan's orbit into the thin upper atmosphere and set up the final
experiment, before the spacecraft's failing power system or dynamic
forces and friction from the Venusian atmosphere shut off communication.
Magellan gathered scientific data on the planet's upper atmosphere, including
aerodynamic interactions with it during the spacecraft's final descent, by
orienting its wing-like solar panels in opposite directions, like a windmill.
The termination experiment was an extension of the windmill experiment
performed in early September. It was carried out as the spacecraft was within
weeks, if not days, of the end of its useful life due to expected decreases
in solar power output from the thermal stress produced by more than 15,000
orbits of Venus.
Launched in May 1989, Magellan entered Venus orbit in August 1990 and gathered
data for over four years. The mission exceeded all of the objectives defined
for its exploration of Venus.
It used radar to map 98 percent of the planet's cloud- covered surface to an
average resolution of better than 300 meters and compiled a high-resolution,
comprehensive gravity field map for 95 percent of the planet. The gravity
data will allow scientists to see "underneath the planet's skin" and compare
that knowledge of the interior to the wealth of surface features revealed by
Magellan's radar imaging, said Project Manager Doug Griffith at NASA's
Jet Propulsion Laboratory (JPL), Pasadena, Calif.
"The tremendous success of the Magellan program was made possible by the
dedicated NASA, JPL , Martin Marietta (Denver) and Hughes Aircraft (Los
Angeles) team that built the spacecraft and its radar, and operated the
mission," Griffith said. "The data which streamed back from Magellan's radar
images, its atmospheric studies, and its gravity data acquisition maneuvers
have built a vast database of new knowledge about Venus and the formation of
the solar system that will be studied by scientists for decades to come."
Magellan also performed a first-of-a-kind "aerobraking" maneuver by dipping
into the atmosphere to reshape its orbit. This technique is now being used in
the design of the Mars Global Surveyor mission to enable the spacecraft to
enter orbit around the planet Mars in 1997 using less fuel, resulting in
significant savings of weight and cost.
"The Magellan mission to Venus has been successful beyond all expectations,"
said JPL Director Dr. Edward C. Stone. "It not only fulfilled its science and
mission objectives, it also demonstrated innovative technologies for future
missions."
|
| 456.638 | RIP Magellan | AUSSIE::GARSON | achtentachtig kacheltjes | Thu Oct 13 1994 10:02 | 1 |
| ...a successful mission by any standards. Onwards and upwards...
|
| 456.639 | It was alive for another 6 hours anyway | SKYLAB::FISHER | Indecision is the key to flexibility! | Tue Oct 18 1994 17:28 | 7 |
| Someone from JPL related in the usenet that while they lost lock at 3:02AM, they
continued to receive intermittant 1-way transmissions from Magellan for another
6 hours. No info as to the content (if any) of the transmissions. If they did
not manage to lock on to the signal, they may have been unable to get any data
out of it in any case.
Burns
|
| 456.640 | Last words? | KELVIN::MCKINLEY | | Thu Oct 20 1994 16:50 | 12 |
|
>Someone from JPL related in the usenet that while they lost lock at 3:02A, they
>continued to receive intermittant 1-way transmissions from Magellan for another
>6 hours. No info as to the content (if any) of the transmissions.
The content of the last transmission from Magellan was just released:
"Help me! I'm falling and I can't get up!"
(sorry...)
---Phil
|
| 456.641 | Thanks for sharing that with us | ROGER::GAUDET | Because the Earth is 2/3 water | Thu Oct 20 1994 18:35 | 5 |
| Phil, somebody had to say it. :-)
Adieu, Magellan. You served us well and will continue to serve for a long time.
...Roger...
|
| 456.642 | Final Magellan Status Report | SKYLAB::FISHER | Indecision is the key to flexibility! | Fri Oct 21 1994 15:34 | 60 |
| Magellan Status Report - October 13, 1994
*****************************************
Forwarded from the Magellan Project
Magellan Significant Events for Week Ending 10/14/94
1. Communication with the Magellan spacecraft was lost early Wednesday
morning, following an aggressive series of five Orbit Trim Maneuvers
(OTMs) on Tuesday, October 11, which took the orbit down into the upper
atmosphere of Venus. The Termination experiment (extension of
September "Windmill" experiment) design was expected to result in final
loss of the spacecraft due to a negative power margin. This was not a
problem since spacecraft power would have been too low to sustain
operations in the next few weeks due to continuing solar cell loss.
Thus, a final controlled experiment was designed to maximize mission
return. This final, low altitude was necessary to study the effects of a carbon
dioxide atmosphere.
2. The final OTM took the periapsis to 139.7 km (86.6 miles) where the
sensible drag on the spacecraft was very evident. The solar panel
temperatures rose to 126 deg. C. and the attitude control system fired all
available Y-axis thrusters to counteract the torques. However, attitude
control was maintained to the end.
3. The main bus voltage dropped to 24.7 volts after five orbits, and it was
predicted that attitude control would be lost if the power dropped below 24
volts. It was decided to enhance the windmill experiment by changing the
panel angles for the remaining orbits. This was also a preplanned
experiment option.
At this point, the spacecraft was expected to survive only two orbits.
4. Magellan continued to maintain communication for three more orbits,
even though the power continued to drop below 23 volts and eventually
reached 20.4 volts. At this time, one battery went off-line, and the
spacecraft was defined as power starved.
5. Communication was lost at 3:02 AM PDT just as Magellan was about to
enter an Earth occultation on orbit 15032. Contact was not re-established.
Tracking operations were continued to 11:00 AM but no signal was seen,
and none was expected. The spacecraft should land on Venus by 1:00 PM
PDT Thursday, October 13, 1994.
6. The Magellan Project Office received many requests for television and
radio interviews relating to the demise of the spacecraft. All requests were
very positive in nature, relating to the tremendous success of the Magellan
mission.
7. This is the last regular Magellan report.
Magellan Status Reports
Magellan Home Page
|
| 456.643 | RIP Magellan | 56821::BATTERSBY | | Fri Oct 21 1994 15:51 | 8 |
| The information on the bus voltages, aolar panel temps, & other
details are somewhat fascinating. It really does give a nice insight
as to how much they can pull out of the telemetry data, even when it's
getting ratty and marginal to pick out of all the grass.
Looks like the operational margin they had was better than they
expected.
Bob
|