Conference 7.286::space

Newsgroups: sci.space
Subject: Pioneer data reveals nature of the outer heliosphere 
Posted: 16 Jul 88 18:41:12 GMT
Organization: NASA Ames Research Center, Moffett Field, CA
 
Charles Redmond
Headquarters, Washington, D.C.                     July 15, 1988
 
Peter W. Waller
Ames Research Center, Mountain View, Calif.
  
RELEASE:  88-100
 
    PIONEER DATA REVEALS NATURE OF THE OUTER HELIOSPHERE
  
    As NASA's Pioneer 11 and Voyager 2 pass through the outer reaches
of the solar system and NASA's Pioneer 10 speeds far beyond the
planets, these distant spacecraft are measuring drastic changes in the
flow patterns of the solar wind -- a million-mile-an-hour stream of
charged particles which constantly boil off the Sun. 
 
    NASA scientists have discovered a connection between the speed
changes in the solar wind (near the spacecraft) and periodic changes
in the Sun itself.  The Sun's constant variations are manifested in
shifts of its magnetic field and movements in the hot gases of its
corona.  Streams of faster wind particles tend to flow from thin
areas, called corona holes, in the corona.  Solar wind changes also
are triggered by movements of a vast electromagnetic structure, called
the current sheet, which bisects the Sun's field.  Particles slow down
as this sheet "flaps" toward them. 
 
    Over the last 3 years, the Sun has been going through a phase
called solar minimum -- a turning point in its 11-year cycle.  "No one
knew what happened during solar minimum in the farthest reaches of the
solar system and beyond until the Pioneers and Voyager sent back their
measurements.  This is the first solar minimum for which we have been
able to see what's going on in the solar wind out past Pluto," says
NASA astrophysicist John Mihalov. 
 
    The solar wind streams out from the Sun and envelops the entire
solar system in charged particles, mostly electrons and protons.  No
one knows exactly how far this five-particle-per cubic-centimeter flow
of particles extends.  One recent guess is about 18 billion miles, or
four times the distance of Neptune from the Sun. 
 
    Before 1985, Pioneer 10 and Voyager 2, both positioned near the
equatorial plane, measured periodic gusts in the solar wind called
"high speed streams."  The particles would speed up and then slow down
about once every 27 days.  In June 1985, the wind stream pattern
stopped and the winds slowed down dramatically at Voyager 2's distance
-- two billion miles from the Sun.  There was no slowing measured at
Pioneer 11, about the same distance as Voyager 2, but 15 degrees
higher in latitude.  Pioneer 11 measured the usual pattern of high
speed streams.  Eventually, the winds were flowing only about half as
fast at Voyager 2 as they were at Pioneer 11. 
 
    Three months later, in August, the solar wind slowed and the high
speed streams also stopped at Pioneer 10, which is out twice the
distance of the other two probes and in the equatorial region. 
Mihalov believes this change is connected to the earlier wind speed
decrease at Voyager 2.  The first slower particles, which were blowing
past Voyager 2 in June, would have just reached Pioneer 10 by August. 
Solar winds actually sped up at the higher altitude position of Pioneer 11. 
 
    The Sun's slower particles, that first reached Voyager and Pioneer
10, were boiling off in March of 1985.  Mihalov and Aaron Barnes,
Ames' senior scientist, proposed that changes in the Sun at this time,
set off the changes in the far solar wind, which reached the vicinity
of the distant probes months later. 
 
    The changes in the Sun were part of a regular variation that it
undergoes in 11-year cycles, or sunspot cycles.  This cycle affects
the number of sunspots, the configuration of the magnetic field, and
the distribution of the 2-million-degree gas making up the solar corona. 
 
    The coronal holes are located around the Sun's North and South
poles.  When the Sun approaches the part of its most active phase,
called solar maximum, these coronal holes creep toward the equator by
extending "tongues" 10 or 20 degrees in longitude.  In the last 3
years, the Sun has been near the opposite condition, called solar
minimum, when the holes retreat back toward the direction of the poles. 
 
    The wind blows out fastest from these lower density holes. Barnes
explains that holes form in areas where strong winds have blown the
coronal particles away.  As the holes retreat toward the poles, the
high-speed streams migrate along with them. 
 
    The Sun's magnetic field also influences the solar wind. The Sun's
field, like Earth's, has basically a North and South magnetic pole,
but the Sun's more complex magnetic field deviates from this dipolar
structure during parts of the solar cycle, becoming most complicated
during solar maximum, when the two magnetic poles swap places. 
 
     In Earth's simpler magnetic field, field lines (the lines
following the direction of force Earth would exert on a magnetic
object) wrap around the planet, connecting the North and South
Magnetic Poles.  In the Sun's field, the solar wind stretches the
Sun's field lines near the equator far out into space.  One region,
corresponding loosely with one hemisphere, has more field lines
pointing out from the Sun, and is called the positive sector, while
the remaining region, with more field lines coming in, is called the
negative sector.  These sectors are divided by an equator, so at the
Sun's surface, a point 15 degrees North of the equator would be above
this equator in some areas and below it in others. 
 
    Away from the Sun, the positive and negative sectors are bisected
by an imaginary wavy curtain called the current sheet, which extends
from this buckled equator.  (It is called the current sheet because
laws of physics state that there must be an electric current at the
boundary between opposite magnetic fields and, indeed, there is a net
flow of positive charges outward and negative particles inward in this
region.)  During the present solar cycle, the region above the current
sheet is the negative sector and, below it, the positive sector. 
 
    Back in early 1985, Pioneer 11 -- 15 degrees above the equatorial
plane -- would sometimes be above and beneath the "current sheet" as
the Sun rotated.  Normally, as the Sun approaches solar minimum and
the coronal holes retreat toward the poles, the current sheet's ridges
flatten out.  As the Sun approached solar minimum in 1985, Pioneer 11
was located above the current sheet, in the negative sector more of
the time.  By mid-1985, Pioneer 11 was always in the negative sector,
indicating that the current sheet had flattened out beneath it. 
 
    The closer you go to the current sheet, the slower the solar wind.
 As the current sheet "flapped" down toward the equator, even with
Voyager 2 and Pioneer 10, the solar winds slowed in this region and
sped up near the poles.  The equatorial winds slowed as far as Pioneer
10, showing that the Sun's magnetic field and the associated current
sheet are exerting powerful control over the solar wind even at great
distances. 
 
    "The Sun, its corona and magnetic fields, and the solar wind are
all part of one system," says Barnes.  And even well past Pluto, the solar 
winds are apparently still under the control of the rest of the system. 

Newsgroups: sci.space,sci.space.shuttle
Subject: Space news from June 20 AW&ST
Posted: 10 Aug 88 04:51:22 GMT
Organization: U of Toronto Zoology
 
    PIONEER 10 celebrates its fifth anniversary technically outside
the Solar System, still returning data.  Someone asked TRW whether
there was a warranty on PIONEER 10; the reply was "TRW's position has
been that if you bring it back, we'll fix it." 
 
    Henry Spencer at U of Toronto Zoology
    uunet!attcan!utzoo!henry henry@zoo.toronto.edu

Newsgroups: sci.astro
Subject: Re: PIONEER 10
Posted: 31 Aug 88 21:08:41 GMT
Organization: Amdahl Corporation, Sunnyvale  CA
 
    In article <48@sunset.MATH.UCLA.EDU> hgw@MATH.UCLA.EDU () writes:

>Is PIONEER 10 still sending information back to Earth?  But are there 
>other data gathering devices working and sending back information?  Is 
>there anybody here on Earth analysing these data?
 
    Yes, PIONEER 10 is alive and well, and is in the Heliospheric Mission 
phase.  Here is the current status of the spacecraft and its systems: 
 
Spacecraft         Star Sensor Inoperative
                   Spacecraft past Sun Sensor sensitivity - Imaging
                   Photopolarimeter used as a star sensor.
 
Science Instruments                  Status   Principal Investigator
 
Vector Helium Magnetometer           Failed 11/16/75
Plasma Analyser                      OK       Aaron Barnes
Charged Particle Instrument          OK       John A. Simpson
Cosmic Ray Telescope                 OK       Frank B. McDonald
Geiger Tube Telescope                OK       James A. Van Allen
Trapped Radiation Detector           OK       R. Walker Fillius
Asteroid-Meteoroid Detector          Power Off
Meteoroid Detector                   Power Off
Ultraviolet Photometer               OK       Darrell L. Judge
Infrared Radiometer                  Power Off
Imaging Photopolarimeter             See Above
 
    Remember that this is a spinning spacecraft, not 3-axis
stabilized.  So, maneuvers are only for assuring orientation of the
"dish" antenna with Earth.  The supply of orientation gas is adequate
well beyond 1994.  Currently, PIONEER 10 is approximately 44 AU from
the Sun and has yet to encounter the Heliopause.  The RTGs (Radioisotope 
Thermo-electric Generators) are still supplying sufficient power, but 
instrument power sharing will soon be necessary.  There should be sufficient 
power for continued scientific investigation until at least 1994. 
 
    Alan Fernquist
    alanf@amdahl.uts.amdahl.com
 
    (In a past life, Assistant Flight Director, Pioneer Missions)

    Any new updates on Poineer 10 and 11 ?.
    
    Plus:
    
    	Can any of you tell me:
    
    		1. Current speeds of these two craft and are they slowing
    		   down ?
    		2. Current status of instruments (if possible) which are
    		   the most important ?
    		3. When and if the voyagers catch them up ?
    
    Cheers,
    
    

Well, I can answer one with certainty and the others with a greater
margin for error.  They are definitely slowing down.  They are moving
*away* from the sun after all.  However, they are moving fast enough so
that they will never fall back.  By the time the Sun's influence has
become negligible, they will still be moving outward.

I have no reason to believe that the Voyagers will overtake them.  Certainly
not literally, since they are most likely all going in different directions.
I guess it is conceivable that V2 will get enough gravity boost from Uranus
to end up going faster, but I have never heard that.

And regarding the instruments:  I don't know directly which are not working;
however, some things (like the cameras) aren't too useful in any case.
They are, I believe, continuing to measure things like the neutron flux as
they head toward interstellar space.

Burns

re:< Note 435.5 by DECWIN::FISHER "Burns Fisher 381-1466, ZKO3-4/W23" >

>I have no reason to believe that the Voyagers will overtake them.  Certainly
>not literally, since they are most likely all going in different directions.
>I guess it is conceivable that V2 will get enough gravity boost from Uranus
>to end up going faster, but I have never heard that.

Most everything you said is quite true.  However, it is my understanding 
that V2 got enough gravity boost from Jupiter, Saturn, Uranus and soon 
from Nepture (august of this year!) that it is now the fastest object ever 
created by man (hopefully so far).  It will go out farther than any other 
of the outer solar system explorers, given time to overtake them.

Tony

    Re: the last three replies:
    	It is true that the two Pioneers are slowing down as they receed
    from the Sun. I can't recall the exact distances but assuming that
    the a Pioneer is about 4.5 billion miles out (that number sticks
    in my mind), the Pioneers would be slowing down at a rate of about
    2.5 MICRONS/second/second (yes that is right, MICRONS!). That
    translates to about 22 centimeters per second per day. And as the
    Pioneers move further from the Sun, the number decreases.
    	As for the Voyagers "over taking" the Pioneers, it is true that
    sometime in the next 10 to 15 years (I forget the exact figures)
    the two Voyagers will be further from the Sun than the two Pioneers
    since the Voyagers are exiting the solar system at a higher velocity.
    	As far as I know, most of the instruments on the Pioneers are
    still operating. The major exceptions that come to mind are the
    meteoroid/asteroid detectors on both Pioneers and the magnetometer
    on Pioneer 10.
    	I am almost certain that there is more info on the Pioneer's
    current status in this conference. Try DIR/TITLE="PIONEER".
    
    				Drew 

    	The latest information I have seen on the PIONEERs current
    condition is right in this Topic.
    
    	Larry
    

Newsgroups: sci.space
Subject: Pioneer 11 passes Neptune's orbit, leaves Solar System (Forwarded)
Date: 23 Feb 90 17:12:58 GMT
Reply-To: yee@trident.arc.nasa.gov (Peter E. Yee)
Organization: NASA Ames Research Center, Moffett Field, CA
 
Charles Redmond
Headquarters, Washington, D.C.                  February 23, 1990
 
Pete Waller
Ames Research Center, Moffett Field, Calif.
  
    RELEASE:  90-29
 
    PIONEER 11 PASSES NEPTUNE'S ORBIT, LEAVES SOLAR SYSTEM
  
     Pioneer 11 today will cross the orbit of Neptune and become the
fourth spacecraft to leave the solar system, providing a coda to
humanity's first major planetary explorations.  Pioneer 11 will join
Pioneer 10 and Voyagers 1 and 2 in searching for the heliopause, the
point at which the Sun's electromagnetic influence gives way to the
Milky Way galaxy's influence. 
 
     As it crosses Neptune's orbit, Pioneer 11 will be 2.8 billion
miles from Earth.  Neptune's orbit currently marks one measure of the
expanse of the solar system because, for the next 12 years, Pluto's
eccentric orbit carries it inside Neptune's path.  Some scientists
refer to the heliopause as the edge of the solar system.  By that
definition, all four spacecraft are still within the solar system. 
 
     Launched in 1973, Pioneer 11 provided scientists with their
closest view of Jupiter, passing within 26,600 miles of the cloud tops
in December 1974.  The close approach and the spacecraft's speed of
107,373 mph, by far the fastest speed ever reached by a man-made
object, hurled Pioneer 1.5-billion miles across the solar system
toward Saturn. 
 
     Before reaching Saturn in 1979, Pioneer 11 reached an inclination
of 17 degrees above the solar equatorial plane, high enough to
illuminate the true character of the Sun's magnetic field.  Now 780
million miles above the ecliptic plane where most of the planets orbit
the Sun, the spacecraft recently showed that many of the solar cosmic
rays in the heliosphere originate outside the Sun's atmosphere in the
interstellar gas, the space between the stars. 
 
     Pioneer 11 flew to within 13,000 miles of Saturn and took the
first close-up pictures of the planet.  Instruments located two
previously undiscovered small moons and an additional ring, charted
Saturn's magnetosphere and magnetic field, and found its planet-size
moon, Titan, to be too cold for Earth-type life.
 
     Pioneer 11, which will traverse interstellar space in the same
direction as the Sun moves, continues to return good data, but in 3
years, operating the radio transmitter and scientific instruments
simultaneously will be difficult, says NASA Project Manager Richard
Fimmel.  Technical adjustments may extend the craft's life through
1995.  Pioneer 10, with a stronger power supply, may return data
through the year 2000, which would extend its original 30-month design
life to 28 years. 
 
     In June 1983, Pioneer 10 made history by becoming the first human
artifact to leave the solar system, travelling in the direction
opposite Pioneer 11's path.  Today, Pioneer 10 will be 4.5 billion
miles from Earth.  Returning data to Earth at the speed of light
requires 6 hours, 36 minutes.  Pioneer 10 continues to search for the
heliopause for very long-wavelength gravity waves that would further
understanding of Einstein's Theory of Relativity and for evidence of 
a tenth planet. 

     Both Pioneers carry a plaque bolted to their sides which depict
among other things our solar system, a nude male and female human, 
and the location of fourteen pulsars relative to our solar system.
The plaques are designed to give any recipients some idea of the
beings who built and launched the probes.
 
     The Pioneers are managed by the Ames Research Center, Mountain
View, Calif., for NASA's Office of Space Science and Applications. 
The spacecraft were built by TRW Space & Technology Group, Redondo
Beach, Calif. 

From: yee@trident.arc.nasa.gov (Peter E. Yee)
Newsgroups: sci.space
Subject: Pioneer 10 marks new epoch in solar system exploration (Forwarded)
Date: 18 Sep 90 18:14:07 GMT
Organization: NASA Ames Research Center, Moffett Field, CA
 
Michael Braukus
Headquarters, Washington, D.C.                 September 18, 1990
(Phone:  202/453-1549)
 
Peter W. Waller 
Ames Research Center, Moffett Field, Calif.
(Phone:  415/604-9000 )
  
    RELEASE  90-125
 
    PIONEER 10 MARKS NEW EPOCH IN SOLAR SYSTEM EXPLORATION
 
     NASA's Pioneer 10 spacecraft, the first to leave the solar
system, will reach another milestone on Saturday, Sept. 22, 1990.  At
4:19 p.m. EDT, Pioneer 10 will be 50 times farther from the Sun than
the Sun is from planet Earth. 
 
     Reaching the 50 astronomical unit (AU) distance "marks a new
epoch in exploration of the outer solar system," according to Pioneer
experimenter James Van Allen of the University of Iowa. 
 
     Van Allen, discoverer of the radiation belts around Earth which
bear his name, said reaching the 50 AU distance "has been a goal of
physicists for many decades."  When Pioneer 10 reaches that mark, it
will be 4,647,809,899 miles from Earth.  Pioneer already has travelled
farther than any human-made object. 
 
     The AU -- the average distance (93 million miles) between the Sun
and Earth -- is the primary unit used to measure distance within the
solar system. 
 
     Launched on March 2, 1972, Pioneer continues to make discoveries
about the limits of the Sun's atmosphere, called the heliosphere.  The
spacecraft is seeking the boundary between the solar heliosphere and
the true interstellar gas.  Pioneer also continues to search for the
first gravity waves to be detected and for data on the location of a
possible tenth solar system planet. 
 
     Pioneer left the solar system planets behind on June 13, 1983. 
Communication with Pioneer is expected to continue until the year
2000, when Pioneer will be 6.9 billion miles from the Sun. 
 
     The spacecraft's tiny 8-watt radio signal now has fallen to a
signal strength of four billionths of a trillionth of a watt when it
finally reaches the football-field-sized antennas of NASA's Deep Space
Network.  Round-trip transmission time for radio signals to the
spacecraft and back to Earth is 13 hours, 47 minutes, travelling at
the speed of light (186,000 miles per second).  Pioneer's current
speed along its flight path is about 28,900 mph. 
 
     Pioneer was the first spacecraft to cross the asteroid belt, fly
by Jupiter and return pictures and a description of the planet's
magnetic field, interior structure and atmosphere, and the mass of its
moons.  Pioneer's most important finding about the outer solar system
is the extent of the Sun's heliosphere, originally thought to have
ended at the orbit of Jupiter.  Pioneer is now almost 10 times farther
away and still within the solar heliosphere. 
 
     Pioneer carries a plaque for communication with any intelligent
species which may find the spacecraft.  The plaque shows a man and a
woman, Earth, a map of the solar system and location of the solar
system in the Milky Way galaxy.  In the vacuum of space, Pioneer is
expected to survive for millions of years, perhaps as long as Earth
itself (roughly five billion years). 
 
     Pioneer 10 is managed by NASA's Ames Research Center, Monutain
View, Calif.  It was built by TRW Inc., Redondo Beach, California.

What's so special about 50 AUs other than it's a nice round number?  If there
anything different at 50 than at 40 or 60 AUs?  Is it the theoretical halfway
point to the heliopause?  Why has it been a goal for decades?

Wook

    Not to throw too much water on the fire oc achievement, let us remember
    that we're still discussing just over .25 of a lightday, and a much
    smaller fraction of a lightyear....
    
    The universe is a big place.
    
    					-**Ted**- 

From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Pioneer 11 Update - 10/09/90
Date: 9 Oct 90 15:13:24 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
  
                           Pioneer 11 Update
                            October 9, 1990
 
     On October 6, the 70 meter antenna in Goldstone, California, was
unable to obtain lock on the downlink on the Pioneer 11 spacecraft.
The 70 meter antennas in Australia and Spain were also unable to
obtain lock the following day.  The stations are reporting that the
AGC (Automatic Gain Control) is fluctuating from -168 dbm to a
threshold of -180 dbm for a period of 3 to 4 seconds.  It is suspected
that the spacecraft's antenna is off Earth point.  Further uplink
attempts will be made using the high power transmitter at 100kw and
performing continuous sweeps. 

      ___    _____     ___
     /_ /|  /____/ \  /_ /|
     | | | |  __ \ /| | | |      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 11 Update - 10/10/90
Date: 10 Oct 90 15:09:16 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
  
                            Pioneer 11 Update
                            October 10, 1990
 
     Pioneer 11 spacecraft problems continue.  Following the high
power uplink support with the 70 meter antenna in Australia which had
receiver in-lock only every 14 to 20 seconds, the Goldstone 70 meter
station was not able to acquire a good 3-way downlink, except for
about 8 seconds in which 2 frames of telemetry were sent to the
project.  Efforts to get a good downlink continues. 

      ___    _____     ___
     /_ /|  /____/ \  /_ /|
     | | | |  __ \ /| | | |      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 11 Update - 10/11/90
Date: 11 Oct 90 15:32:18 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA. 
 
                        Pioneer 11 Update
                        October 11, 1990
 
     A spacecraft emergency was declared for the Pioneer 11 spaceraft
at 3 PM (PDT) on October 10.  The 70 meter tracking station in
Goldstone supported the emergency yesterday and today using its high
power transmitter at 80 KW. The 70 meter antenna in Australia observed
downlink from Pioneer 11 this morning, and the downlink was observed
1-way and locking at intervals of 3 to 4 seconds.  The longest period
of receiver lock as reported at 20 seconds. 

      ___    _____     ___
     /_ /|  /____/ \  /_ /|
     | | | |  __ \ /| | | |      Ron Baalke         | baalke@mars.jpl.nasa.gov
  ___| | | | |__) |/  | | |___   Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
 /___| | | |  ___/    | |/__ /|  M/S 301-355        |
 |_____|/  |_|/       |_____|/   Pasadena, CA 91109 |

    Can Pioneer and Voyager class sats realign? Also what apart from dust
    would knock it off lock?                   
    
    ta.
    
    Simon 

They are all 3-axis stabilized, so assuming no damage, they should be able to
line themselves up.  In fact, the dish is fixed to the spacecraft, so that is
the only way the steer the dish to begin with.

But lots of things can go wrong.  I suppose something could have it the space-
craft and damaged something related to the pointing mechanism.  The star sensor
could have a problem so that it is lined up wrong (although that seems unlikely
since they are getting periodic temporary locks).  I don't know if the periodic
locks indicate that it is searching for Earth and that it periodically passes
the "right" aim point, or if it might indicate that there is something wrong
with the transmitter (or of course other).

Burns

From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Pioneer 11 Update - 10/15/90
Date: 15 Oct 90 15:14:32 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
  
                              Pioneer 11 Update
                              October 15, 1990
 
     Pioneer 11 spacecraft emergency continues.  Downlink to the 70
meter antenna in Australia is in low noise configuration.  The station
reports that the receivers are locking up for 3 to 4 second intervals.
The AGC (Automatic Gain Control) has been fluctuating from -170 DBM
to below the threshold.  As of this morning, the situation has not
changed. 

      ___    _____     ___
     /_ /|  /____/ \  /_ /|
     | | | |  __ \ /| | | |      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 11 Update - 10/16/90
Date: 16 Oct 90 14:57:15 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
  
                        Pioneer 11 Update
                        October 16, 1990
 
     The Pioneer 11 emergency continues.  The 70 meter antennas in
Spain supported downlink yesterday, and there has been no change to
the status of the spacecraft.  The same antennas will be used today 
to provide a 400 kilowatt uplink. 
 
     For those of you unfamiliar with Pioneer 11 or need their
memories jogged, here is an article posted by Peter Yee last spring
when Pioneer 11 left our solar system. 
------------------------------------------------------------------------
 
    PIONEER 11 PASSES NEPTUNE'S ORBIT, LEAVES SOLAR SYSTEM - March 1990
 
     Pioneer 11 today will cross the orbit of Neptune and become the
fourth spacecraft to leave the solar system, providing a coda to
humanity's first major planetary explorations.  Pioneer 11 will join
Pioneer 10 and Voyagers 1 and 2 in searching for the heliopause, the
point at which the Sun's electromagnetic influence gives way to the
Milky Way galaxy's influence. 
 
     As it crosses Neptune's orbit, Pioneer 11 will be 2.8 billion
miles from Earth.  Neptune's orbit currently marks one measure of the
expanse of the solar system because, for the next 12 years, Pluto's
eccentric orbit carries it inside Neptune's path.  Some scientists
refer to the heliopause as the edge of the solar system.  By that
definition, all four spacecraft are still within the solar system. 
 
     Launched in 1973, Pioneer 11 provided scientists with their
closest view of Jupiter, passing within 26,600 miles of the cloud tops
in December 1974.  The close approach and the spacecraft's speed of
107,373 mph, by far the fastest speed ever reached by a man-made
object, hurled Pioneer 1.5-billion miles across the solar system
towards Saturn. 
 
     Before reaching Saturn in 1979, Pioneer 11 reached an inclination
of 17 degrees above the solar equatorial plane, high enough to
illuminate the true character of the Sun's magnetic field.  Now 780
million miles above the ecliptic plane where most of the planets orbit
the Sun, the spacecraft recently showed that many of the solar cosmic
rays in the heliosphere originate outside the Sun's atmosphere in the
interstellar gas, the space between the stars. 
 
     Pioneer 11 flew to within 13,000 miles of Saturn and took the
first close-up pictures of the planet.  Instruments located two
previously undiscovered small moons and an additional ring, charted
Saturn's magnetosphere and magnetic field, and found its planet-size
moon, Titan, to be too cold for life as we know it.
 
     Pioneer 11, which will traverse interstellar space in the same
direction as the Sun moves, continues to return good data, but in 3
years, operating the radio transmitter and scientific instruments
simultaneously will be difficult, says NASA Project Manager Richard
Fimmel.  Technical adjustments may extend the craft's life through
1995.  Pioneer 10, with a stronger power supply, may return data
through the year 2000, which would extend its original 30-month design
life to 28 years. 
 
     In June 1983, Pioneer 10 made history by becoming the first human
artifact to leave the solar system, travelling in the direction
opposite Pioneer 11's path.  Today, Pioneer 10 will be 4.5 billion
miles from Earth.  Returning data to Earth at the speed of light
requires 6 hours, 36 minutes.  Pioneer 10 continues to search for the
heliopause for very long-wavelength gravity waves that would further
understanding of Einstein's Theory of Relativity and for evidence of a
tenth planet. 
 
     The Pioneers are managed by the Ames Research Center, Mountain
View, Calif., for NASA's Office of Space Science and Applications. 
The spacecraft were built by TRW Space & Technology Group, Redondo
Beach, Calif. 

      ___    _____     ___
     /_ /|  /____/ \  /_ /|
     | | | |  __ \ /| | | |      Ron Baalke         | baalke@mars.jpl.nasa.gov
  ___| | | | |__) |/  | | |___   Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
 /___| | | |  ___/    | |/__ /|  M/S 301-355        |
 |_____|/  |_|/       |_____|/   Pasadena, CA 91109 |

  Can someone translate Pioneer 11's problem into laymans terms? It
looks like there's some kind of communication problem but it doesn't
appear that they have lost it completely. Is that correct?

  George

Yes, they can detect the signal coming from it, but they can't get a "lock".
The reception is done with things called phase-locked loops.  Essentially,
(and this is an over-simplification) the receiver electronics watch the carrier
signal.  If everything is constant and happy, the wave should be at a certain
place (say a 0-crossing) at a certain time.  If some frequency drifts, this is
no longer true (the phase has changed), so the receiver notices and compensates.

When they can't get a lock on the signal, that means that it is getting into
the receiver, but it is not strong enough for the electronics to follow it.
Most likely they can't receive any data from it in this condition.  All they
can tell for sure is that it is still there and transmitting.  It sounds like
they are trying to get P11's attention by blasting commands at it at very high
power.  It would be intersting to know what commands they are sending!

Burns

From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Pioneer 10 & 11 Update - 10/16/90
Date: 16 Oct 90 16:25:06 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
  
                      Pioneer 10 and 11 Update
                         October 16, 1990
 
     Ames Research Center Pioneer operations engineers report separate
anomalies to the Pioneer 10 and 11 spacecraft.  Pioneer 10 telemetry
appears to indicate a slight decline in thruster gas pressure.  The
thrusters are used to perform alignment maneuvers to maintain the
Pioneer's high gain antenna pointing toward Earth.  They are not used
for spacecraft stabilization.  There appears to be no impact resulting
from the low thruster gas pressure.  Pioneer 10 should have enough
pressure for several more years worth of operations. 
 
     The anomaly on Pioneer 11 is that its radio signal has become
variable.  This situation is being further investigated, but could be
a failure in a driver amplifier feeding the transmitter traveling wave
tube.  It is not believed to be in the transmitter tube itself.  Ames
Pioneer engineers and Headquarters Solar System Exploration Division
officials are investigating this situation. 

      ___    _____     ___
     /_ /|  /____/ \  /_ /|
     | | | |  __ \ /| | | |      Ron Baalke         | baalke@mars.jpl.nasa.gov
  ___| | | | |__) |/  | | |___   Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
 /___| | | |  ___/    | |/__ /|  M/S 301-355        |
 |_____|/  |_|/       |_____|/   Pasadena, CA 91109 |

Hey, no problem.  Just program the computer to send data only while the
transmitted signal strength is at its peak!

(This is one of those things said in ironic admiration.  It continues to
blow me away how flexible they built these things to be...)

Burns

From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Pioneer 11 Update - 10/17/90
Date: 17 Oct 90 16:06:29 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
  
                           Pioneer 11 Update
                           October 17, 1990
 
     The Pioneer 11 spacecraft emergency continues.  Yesterday, the 70
meter antenna in Spain used it high power transmitter at 400 kw, and
Ames Research Center reported receiving telemetry intermittently for 8
minutes, 11 minutes, 8 minutes and 19 minutes.  The 70 meter station
in Goldstone also provided uplink support at 400 kw.  The station was
able to verify a 3-way downlink with the 70 meter antenna in Spain,
although receiver lock remained intermittent.  The maximum AGC (Automatic 
Gain Control) was at -172 DBM.  There was no telemetry data acquired 
during this pass. 

      ___    _____     ___
     /_ /|  /____/ \  /_ /|
     | | | |  __ \ /| | | |      Ron Baalke         | baalke@mars.jpl.nasa.gov
  ___| | | | |__) |/  | | |___   Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
 /___| | | |  ___/    | |/__ /|  M/S 301-355        |
 |_____|/  |_|/       |_____|/   Pasadena, CA 91109 |

    Re:.23
    
    	Nice idea but Pioneers 10 and 11 aren't controlled that way. Unlike
    the more sophisticated Vikings, Voyagers, Magellan, and Galileo which
    can store commands and execute them at a particular time, these
    Pioneers must be controlled in real time. If you want Pioneer 10 or 11
    to perform a certain measurement at a certain time, you must send a
    command to it far enough in advance to take into account the signal's
    travel time. There is no computer on board to store and execute
    commands.
    
    				Drew
    

From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Pioneer 11 Update - 10/19/90
Date: 19 Oct 90 15:37:08 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
  
                           Pioneer 11 Update
                           October 19, 1990
 
     The Pioneer 11 spacecraft emergency continues.  Support from the
70 meter antenna in Spain yesterday provided Ames Research Center with
one major telemetry frame.  Ames reported that they were able to verify 
the spacecraft receiver configuration as well as other engineering data. 
They are continuing the analysis of the spacecraft problem at this time.  
The 70 meter antenna in Goldstone also provided high power transmitter 
support last night with a uplink power output of 330 KW. 

      ___    _____     ___
     /_ /|  /____/ \  /_ /|
     | | | |  __ \ /| | | |      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 11 Update - 10/22/90
Date: 22 Oct 90 15:35:08 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
  
                          Pioneer 11 Update
                          October 22, 1990
 
     Two commands transmitted during the first 70 meter Goldstone
support were received by the Pioneer 11 spacecraft last Friday,
October 19.  The project was able to verify the reception of the
commands from the telemetry data they received during support from
Spain's 70 meter station.  The telemetry data is in the engineering
format.  The Spain antenna's uplink achieved spacecraft receiver lock
and the project reported the uplink was received via the spacecraft's
Medium Gain Antenna and they reported a receiver AGC (Automatic Gain
Control) of -151.0 dbm. 
 
     On Saturday, October 20, the 70 meter antenna in Australia
reports intermittent lock on receivers configured for channel 6 1-way
throughout the pass.  Ames Research Center reports they had received
521 block of telemetry data, 56 missing minor frames, and 394 deleted
frames.  The Spain station provided high power support at 350 kw.  The
project sent commands to configure the spacecraft as non-coherent. 
The Spain 70 meter antenna had receiver lock and provided telemetry to
the project slightly less than 50 percent of the pass of which Ames
reported 20 percent was usable.  The average AGC was -169.0 and the
average SNR (Signal-to-Noise Ratio) was at -4.0 db.  The Goldstone
station received downlink in low noise configuration with initial
intermittent receiver lock.  After a solid receiver lock was achieved,
Ames received 1,556 blocks of telemetry data with 730 deleted frames
during the pass. 
 
     On Sunday, October 21, the 70 meter antenna in Spain had solid
receiver lock on Pioneer 11 throughout the entire pass.  The average
AGC was as -167.0 dbm with an average SNR of 4.2 db. 

      ___    _____     ___
     /_ /|  /____/ \  /_ /|
     | | | |  __ \ /| | | |      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 11 article
Date: 22 Oct 90 17:48:49 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
 
     Space News -- Week of Oct. 22. - Oct. 28
     "Pioneer Mission May Be Near End"
 
    "NASA's Pioneer 11 spacecraft, the first satellite to visit
Saturn, is suffering serious communications problems three billion
miles from Earth that threaten to end its historic 17-year mission." 
  
    The paper says that until Oct. 18, ground controllers at the Jet
Propulsion Laboratory had been unable to send any commands to the
craft for two weeks.  The report says a successful command last week
switched the spacecraft from science mode to engineering mode,
enabling it to send more useful data to its Earth-bound controllers. 
 
    The story quotes NASA Ames Research Center Pioneer project chief
Richard Fimmell as saying "if this condition can't be cleaned up, the
mission is over as far as science is concerned." 

      ___    _____     ___
     /_ /|  /____/ \  /_ /|
     | | | |  __ \ /| | | |      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 11 Update - 10/24/90
Date: 24 Oct 90 15:08:03 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
  
                             Pioneer 11 Update
                              October 24, 1990
 
     The Pioneer 11 spacecraft emergency continues with high power
uplink support from the 70 meter stations.  Good telemetry has been
processed with the downlink configured non-coherent on channel 7.  The
high power transmitter was used from the 70 meter antenna in Spain to
command a receiver swap on the spacecraft 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: Pioneer 11 Update - 10/25/90
Date: 25 Oct 90 15:12:24 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
  
                            Pioneer 11 Update
                            October 25, 1990
 
     Pioneer 11 emergency continues, but things are starting to look
much better.  Apparently, the High Gain Antenna was slightly off Earth
point which was causing the communications problem for the past couple
weeks.  Yesterday, the 70 meter antenna in Spain maintained telemetry
throughout its tracking pass.  The project at Ames Research Center
reported all data was usable.  The average AGC (Automatic Gain Control)
was -169.0 dbm with a SNR (Signal-to-Noise Ratio) of 3.8 db. 
 
     Early this morning the 70 meter antenna in Australia provided a
command pass support with 150 kw.  A total of 20 commands were
transmitted.  Ames reported that all 3415 block of telemetry received
back was usable except for one frame.  The average AGC was -166.8 dbm,
SNR 3.5 db. 

      ___    _____     ___
     /_ /|  /____/ \  /_ /|
     | | | |  __ \ /| | | |      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)
Date: 26 Oct 90 16:02:12 GMT
Organization: Jet Propulsion Laboratory, Pasadena, CA.

                             Pioneer 11 Update
                             October 26, 1990
 
     The Pioneer 11 emergency support continues.   Last night, Ames
Research Center requested an increase in the uplink power to 200 kw at
the Goldstone 70 meter station, as the previous uplink with the 70 meter
station in Australia did not acquire the spacecraft using 150 kw.  Ames
reported that the commands transmitted during the previous uplink were
not critical.  Five commands were transmitted during the Goldstone pass.
Ames reported receiving 2299 blocks of telemetry with 1 frame deleted and
1 sequence error with the Goldstone antenna.
      ___    _____     ___
     /_ /|  /____/ \  /_ /|
     | | | |  __ \ /| | | |      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)
Date: 29 Oct 90 17:26:22 GMT
Organization: Jet Propulsion Laboratory, Pasadena, CA.

                             Pioneer 11 Update
                             October 29, 1990
 
     The Pioneer 11 spacecraft emergency support continues with 70 meter
antennas in high power transmitter uplink configuration.  Non-coherent
downlink telemetry has been processed by Ames Research Center.  Following
the uplink with the 70 meter antenna in Spain yesterday, the 70 meter
antenna in Goldstone was unable to acquire 3-way downlink.  The project
at Ames reports commands are getting into the Pioneer 11 spacecraft, but
the planned receiver swap was not successful.
      ___    _____     ___
     /_ /|  /____/ \  /_ /|
     | | | |  __ \ /| | | |      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 11 Update - 10/30/90
Date: 30 Oct 90 16:05:42 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
  
                             Pioneer 11 Update
                             October 30, 1990
 
     The Pioneer 11 spacecraft emergency was terminated at 3:29PM (PST)
  yesterday.

      ___    _____     ___
     /_ /|  /____/ \  /_ /|
     | | | |  __ \ /| | | |      Ron Baalke         | baalke@mars.jpl.nasa.gov
  ___| | | | |__) |/  | | |___   Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
 /___| | | |  ___/    | |/__ /|  M/S 301-355        |
 |_____|/  |_|/       |_____|/   Pasadena, CA 91109 |

    Why?
    
    Was the craft lost?
    
    Did something happen that made communication possible again?
    
    Tony

    Re:.33
    
    	I would assume that since they seem to have been steadily improving
    communications over the past few days that the emergency has ended with
    Pioneer 11 essentially operational.
    
    				Drew
    

  Probably right, but that's sort of like saying "The man that was dieing is no
longer being cared for in the hospital". 

  Maybe he walked out the door and maybe he got wheeled to the morgue.

  George

Last I remember they were trying to blast commands at it to switch primary
receivers.  Perhaps that effort was finally successful.

Does anyone know what relationship the signal received by P has to the signal
transmitted?  For example, does P use the signal from earth to aim itself?
Does that mean that the DSN has to start sending out a homing signal several
hours before they expect any data?  I never thought this was the case...I
thought it was essentially inertial nav+star updates, but some stuff about
the emergency seemed to imply differently.

Another BTW:  Did anyone see anything about the emergency in AvWeek?  I did
not and was rather surprised.

Burns

From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Pioneer 11 Update - 11/01/90
Date: 2 Nov 90 00:38:09 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
  
                            Pioneer 11 Update
                            November 1, 1990
 
     The Pioneer project at Ames Research Center cancelled the Pioneer
11 spacecraft's "State of Emergency" for DSN (Deep Space Network)
service on October 29.  The following is an outline of what happened
and the present status of the spacecraft. 
 
     Downlink communications failed on October 7, 1990, beginning with
noise and worsening to inability to lock on downlink in a matter of a
few minutes during a track of one-way signal (ie: with no uplink a 9
hour RTLT (round trip light time) earlier).   Subsequent tracks
permitted only sporadic bits of data which indicated nonresponsiveness
to uplink commands and showed no reason for the failure mode. 
Emergency priority was necessary to provide for round-trip scheduling
of high power uplink with "real-time" monitoring of effects of
attempts at correction, so a spacecraft emergency was declared on
October 10.  A series of trials has resulted in recovery of an
operable condition and has disclosed the following interpretation of
the problem. 
 
     Receiver-B, connected to the high gain antenna on the spacecraft,
has developed an internal noise source.  That source renders its
receiver (B) inoperative in terms of receiving and decoding commands,
and it intermittently signals the transponder and the receiver antenna
switch logic that Receiver-B is operating.  The noise also disrupted
the down link via the transponder, as shown when the coherent mode was
eventually commanded off.  Furthermore, that noise is suspected as the
source of signal which upset the logic in Receiver-A. Receiver-A is
connected to the medium gain antenna, making it slightly beyond the
the DSN's high power uplink according to link budget.  However,
Receiver-A has been successfully commanded several times after
transmitting a logic reset code never previously used; and uplink of
200 KW or more appears successful at its present distance.  The
received signal strength is about 5 dB below specification sensitivity
of the spacecraft.  The switch to reverse antenna connections to place
Receiver-A on the spacecraft's high gain antenna has not responded to
5 attempts. 
 
     The current status of Pioneer 11 is that it is operable only with
200 KW (to be increased with distance) and without coherent signal. 
Receiver-A developed a less troublesome noise in its coherent mode in
1983.  Measurement of spin axis orientation is being attempted, and
might be a continuing difficulty.  Further investigation and possible
attempts to improve configuration will be made in the coming weeks. 
 
     Ames hops to complete related activities under normal scheduling,
but subject to regular use of high powered uplink from 70 meter
stations and to possible infrequent additional support for measuring
orientation. 

      ___    _____     ___
     /_ /|  /____/ \  /_ /|
     | | | |  __ \ /| | | |      Ron Baalke         | baalke@mars.jpl.nasa.gov
  ___| | | | |__) |/  | | |___   Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
 /___| | | |  ___/    | |/__ /|  M/S 301-355        |
 |_____|/  |_|/       |_____|/   Pasadena, CA 91109 |

I take it that "coherent mode" somehow synchronizes transmission with the
received signal, so that with the receiver knarled up, it could not transmit
properly?

Burns

    Maybe they declared the emergency over, but the spacecraft sounds
    terminal to me.
    
    Tony

From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Pioneer 10 Update - 11/02/90
Date: 5 Nov 90 23:37:00 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
  
                        Pioneer 10 Status Report
                          November 2, 1990
 
     On October 26, the 70 meter antenna at Goldstone had difficulty
acquiring telemetry from the Pioneer 10 spacecraft, reason unknown. 
Telemetry lock was eventually achieved with a 27 minute outage.  The
propellant tank pressure telemetry point began to toggle between 198.0
and 188.8 psi on October 15.  This is only a 1 data number range.  At
this time the pressure reading is still toggling but remains at 188.8
psi for the majority of the data samples. 

      ___    _____     ___
     /_ /|  /____/ \  /_ /|
     | | | |  __ \ /| | | |      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 11 Update - 11/02/90
Date: 5 Nov 90 23:38:37 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
  
                          Pioneer 11 Status Report
                              November 2, 1990
 
     The Pioneer 11 spacecraft is still operating with Receiver A on
the Medium Gain Antenna (MGA).  The uplink margin for the MGA has been
established to be somewhere between 150 and 191 kw.  Receiver B on the
High Gain Antenna (HGA) still has not responded to commands at 350 kw.
Commands were addressed to both decoders but the command was unsuccessful. 
 
     On October 29, a CONSCAN procedure was transmitted over the 70
meter antenna in Spain at 350 kw.  This used the MGA to determine the
spacecraft's attitude.  However, it appears that due to the low signal
strength, large errors are introduced when the CONSCAN Signal Processor 
determines the pointing amplitude and phase, making the telemetered 
data unusable. 
 
     On October 31, the spacecraft was commanded back to Format A.  No
science data was collected from October 6 through October 31.

      ___    _____     ___
     /_ /|  /____/ \  /_ /|
     | | | |  __ \ /| | | |      Ron Baalke         | baalke@mars.jpl.nasa.gov
  ___| | | | |__) |/  | | |___   Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
 /___| | | |  ___/    | |/__ /|  M/S 301-355        |
 |_____|/  |_|/       |_____|/   Pasadena, CA 91109 |

RE .25 and .-1:  Doesn't this last bit about COMSCAN indicate the P11 does
have a computer aboard?

Burns

  I don't think that anyone ever said Pioneer 11 didn't have a computer. I
believe that the point is that it can not be reprogrammed the way the Voyager
computer can. Most likely the software is in ROM. 

  Also, it can't be given blocks of commands but can only be given one command
at a time. In other words, you can tell it the VMS equivilent of:

    SHOW DEV SYS$DISK

but not

    @SHOW_ALL_DISKS.COM

  George

    Re:.42
    
    	You're on the right track: Pioneer 10 and 11 do have a computer, of
    sorts, but they are very rudimentary. Their exact name escapes me but
    the computer is more of a command processor and sequencer. They process
    incoming commands and convert them into signals that perform various
    functions (e.g. turning instruments on and off, switching to various
    transmission speeds or formats, etc.). As I have mentioned before, the
    computers cannot be reprogrammed or store blocks of commands. These
    spacecraft can only be controlled in "real time".
    
    				Drew
    

From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Pioneer 10 Update - 11/16/90
Date: 21 Nov 90 00:54:42 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
  
                      PIONEER 10 STATUS REPORT
                         November 16, 1990
 
     A precession maneuver, scheduled for December 16 has been
cancelled.  Due to the increase in angular acceleration of the
spacecraft and limited tracking, the roll phase analysis has been
unsuccessful in producing a reliable data base for predicting the roll
phase.  These data, obtained during two-way tracking, are required for
planning the maneuver.  As a result, the Earth Look Angle (ELA) will
increase to a maximum of 1.1 degrees during February and March, 1991,
and then drift back down to below 1.0 degrees. 

      ___    _____     ___
     /_ /|  /____/ \  /_ /|
     | | | |  __ \ /| | | |      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 11 Update - 11/16/90
Date: 21 Nov 90 00:56:16 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA. 
 
                      PIONEER 11 STATUS REPORT
                         November 16, 1990
 
     Attempts to pulse the receiver switch assembly on November 9 were
unsuccessful.  It appears that the stored command sequence, with 0
second time delays between commands, did not execute.  On November 16,
the sequence will be tried again with 1 second delays. 

      ___    _____     ___
     /_ /|  /____/ \  /_ /|
     | | | |  __ \ /| | | |      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 11 Update - 11/23/90
Date: 26 Nov 90 15:48:26 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA. 
 
                     PIONEER 11 STATUS REPORT
                       November 23, 1990
 
     Attempts to switch receivers on the Pioneer 11 spacecraft by
stored command load on November 16 failed.  On November 17, telemetry
indicated that the switch did not occur. Also, for unknown reasons the
antenna feed was in the offset position, and the Meteorite Detector
instrument was powered on.  This caused the battery to come on line. 
 
     Analysis of recent command activities has shown that commands are
failing to execute at the beginning of a sequence, and following a
delay or break in commanding.  Procedures have been modified to
include test commands or repetitive commands at the beginning of
command sequences. 
 
     The spacecraft was configured for engineering format with all
instruments off on November 17.  Stored repetitive command sequences
to attempt a receiver switch were loaded on November 22 and 23. 
Confirmation of the command execution is awaiting the next scheduled
track. 

      ___    _____     ___
     /_ /|  /____/ \  /_ /|
     | | | |  __ \ /| | | |      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 11 Update - 11/30/90
Date: 30 Nov 90 16:50:01 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
  
                       PIONEER 11 STATUS REPORT
                          November 30, 1990
 
     Stored repetitive 5-minute command sequences to switch receivers
on the Pioneer 11 spacecraft were confirmed.  The commands were
transmitted on November 22 and 23.  However the receiver switch did
not occur.  The sequences will be repeated as often as possible. 
 
     On November 26, the high gain main feed was offset for 1 hour,
and AGC (Automatic Gain Control) data was collected.  The data are
being analyzed to look for some periodicity, indicating the spacecraft
spin rate.  It is hoped that these data, in conjunction with the Sun
pulse, will generate a spacecraft attitude.  CONSCAN measurements have
been unable to be performed with the medium gain antenna. 
 
     A scheduled 70 meter Goldstone track on November 27 was cancelled
due to a cracked subreflector brace. 
 
     A precession maneuver is scheduled for November 30.  Nine
quadrature pulses will be fired.  This maneuver is being executed
without accurate knowledge of the previous attitude because of the
inability to perform CONSCAN measurements with the medium 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: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Pioneer 6 Update - 12/17/90
Date: 17 Dec 90 16:59:09 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
  
                            PIONEER 6 STATUS REPORT
                              December 17, 1990
 
     Yesterday, December 16, 1990, marked the 25th anniversary of the
launch of the Pioneer 6 spacecraft.  A tracking pass was performed by
the 70 meter antenna at Goldstone, California, the first of two
scheduled supports.  The Goldstone antenna provided telemetry and
tracking data, and radiated 4 commands.  The average AGC (Automatic
Gain Control) is at -170.0, the SNR is 3.0 and the telemetry data rate
is at 16 bits/second.  There were no problems encountered during the
tracking pass.  Pioneer 6 was last supported on July 4, 1990, by the
70 meter antenna in Spain.  Goldstone will provide another tracking
pass today starting at 9 AM (PST). 

      ___    _____     ___
     /_ /|  /____/ \  /_ /|
     | | | |  __ \ /| | | |      Ron Baalke         | baalke@mars.jpl.nasa.gov
  ___| | | | |__) |/  | | |___   Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
 /___| | | |  ___/    | |/__ /|  M/S 301-355        |
 |_____|/  |_|/       |_____|/   Pasadena, CA 91109 |

  So where is Pioneer 6 (earth orbit, solar orbit, etc) and what did it go
there to do? Did they just track it floating around like a hunk of metal
or is it still active?

  George

    They had a neat story on CNN Headline News about Pioneer 6 last
    night.  It is still active, and has recently done some measurements
    of the solar wind.  Quite impressive that it is still operating
    after 25 years.  I believe it is in a solar orbit which takes it
    near Earth orbit (at least, that's how the JPL animation looked).

From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Pioneer 11 Update - 12/18/90
Date: 18 Dec 90 16:15:07 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
  
                    PIONEER 11 STATUS REPORT
                      December 18, 1990
 
     On November 8, several commands failed to execute on the Pioneer
11 spacecraft, including receiver switch commands.  The USC/UV off
command, and the ARC/PA configuration commands also were not executed.
In an attempt to evaluate these intermittent command failures,
several benign status change commends are included in the command
sequences.  The lack of tracks one roundtrip time after commanding,
makes a determination of the success or failure of the commands
difficult.  Superior Conjunction will occur today. The minimum Earth
Probe Sun angle will be 0.47 degrees. 

      ___    _____     ___
     /_ /|  /____/ \  /_ /|
     | | | |  __ \ /| | | |      Ron Baalke         | baalke@mars.jpl.nasa.gov
  ___| | | | |__) |/  | | |___   Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
 /___| | | |  ___/    | |/__ /|  M/S 301-355        |
 |_____|/  |_|/       |_____|/   Pasadena, CA 91109 |

From: mrb1@cbnewsh.att.com (maurice.r.baker)
Newsgroups: sci.space.shuttle
Subject: Re: Pioneer 6
Date: 19 Dec 90 19:41:25 GMT
Organization: AT&T Bell Laboratories
 
    In article <90352.073839TACON019@ysub.ysu.edu>, TACON019@ysub.ysu.edu 
(Fred Ullom) writes: 

> I saw on the news this morning that today is the 25th anniversary of
> Pioneer 6. They said it was the oldest functioning satellite.
 
According to a nice article in the 12-17-90 issue of SATELLITE NEWS,
its original 1965 design life was only 6 months!
  
> What type of data is pioneer 6 recording? and do we still find this
> information useful? or by "functioning" do they mean simple that it
> still works and its long outlived its usefulness.
 
It still sends back scientific data although only 3 of its 6 onboard
experiments still work.  It is monitored by the Deep Space Network some-
what intermittently due to the demands of Galileo, Ulysses, Magellan,
etc.  It will be tracked for 2 hours on 12/17, perhaps in honor of its
25th anniversary.  The last time it was tracked was 7/4/90, just to
give you a perspective on what "intermittently" means.
 
It sends back plasma and charged particle data, and can still be used for
solar wind experiments when other conditions are acceptable.
 
Of particular interest to sci.space.shuttle readers who have followed the
recent discussion on solar flare warning satellite development, etc. is that
Pioneer 6 has warned of solar storms several weeks in advance of their ar-
rival here on Earth.  It can send back solar flare data from the "back
side" of the Sun before the active part rotates towards Earth.
 
From a historical perspective, Pioneer 6 has travelled about 15.6 billion
miles (apologies to the metric system fans out there :-)) and transmitted
back more than 15 billion bits of data on the Sun.  It made the 1st detailed
measurements of the Sun's atmosphere as well as measuring its corona and
the Comet Kohoutek tail in 1973-74.
 
For the fiscally minded, it was built by TRW under NASA contract and launched
in 1965 for about $6 million [in 1965 dollars].
 
Dr. Alan Lazarus of MIT (who works with Dr. Herbert Bridge, original
principal researcher for project) was quoted as saying:
 
	"The project had a short management chain.  Charlie Hall [original
		project mgr.] really insisted on that and it was very
		successful.  When everyone has to sign off on everyone
		else's job it gets very expensive.  The management team
		was very close to the experimenters and was able to give
		quick feedback and there was not a lot of paperwork.  Some
		of today's projects might be able to benefit from going
		back to basics in the structure of things."
 
'Nuff said....
 
M. Baker
homxc!jj1028
 
(with thanks to SATELLITE NEWS for this unauthorized reference to its
article.  It's published by Phillips Publishing, Inc. at 301-340-2100.)

From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Pioneer 10 Update - 12/21/90
Date: 21 Dec 90 17:24:43 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
  
                      PIONEER 10 STATUS REPORT
                        December 21, 1990
 
     On December 16, a TPA (Telemetry Processing Assembly) failure at
the 70 meter station in Australia caused a 32 minute loss of telemetry
data for the Pioneer 10 spacecraft. 
 
     A CONSCAN and IPP procedure will be transmitted on December 21. 
AGC (Automatic Gain Control) data will be gathered during both procedures, 
to allow a comparison between the two   This is being done for further 
evaluation of whether AGC data can be used to determine spacecraft attitude. 

      ___    _____     ___
     /_ /|  /____/ \  /_ /|
     | | | |  __ \ /| | | |      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 11 Update - 12/21/90
Date: 21 Dec 90 17:26:41 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
  
                       PIONEER 11 STATUS REPORT
                          December 21, 1990
 
     Attempts to switch receivers on the Pioneer 11 spacecraft on
December 13 and 16 were unsuccessful.  On December 13, the switch
commands were loaded in the stored command logic, but failed to
execute, apparently because the decoder did not de-squelch.  On
December 16, a second attempt was made by transmitting an "idle-1"
sequence for 5 minutes, followed by 50 real-time switch commands. 
This method will be used on all future receiver switch attempts. 

      ___    _____     ___
     /_ /|  /____/ \  /_ /|
     | | | |  __ \ /| | | |      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 10 Update - 01/04/91
Date: 7 Jan 91 23:45:08 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA. 
 
                        PIONEER 10 STATUS REPORT
                            January 4, 1991
 
     On December 29, there was an uncommanded status change to the
ARC/PA instrument on the Pioneer 10 spacecraft.  The instrument was
returned to the proper configuration following notification of the
investigator. 
 
     On December 30, predicted RFI at the 70 meter station in Spain
caused a 23 minute loss of telemetry, and 32 minutes of degraded
telemetry.  On January 1, subreflector problems at the Goldstone 70
meter station caused a 1 hour loss of telemetry data.  On January 2,
predicted RFI caused another 1 hour loss of telemetry. 

      ___    _____     ___
     /_ /|  /____/ \  /_ /|
     | | | |  __ \ /| | | |      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 11 Update - 01/04/91
Date: 7 Jan 91 23:46:32 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
  
                         PIONEER 11 STATUS REPORT
                           January 4, 1991
 
     Further attempts to switch receivers on the Pioneer 11 spacecraft
were made on December 29.  All commands were executed, but the
receiver did not switch.  A new power sharing plan was implemented on
January 3.  The ARC/PA and the GSFC/CRT instruments will remain on
during January 1991. 

      ___    _____     ___
     /_ /|  /____/ \  /_ /|
     | | | |  __ \ /| | | |      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 10 Update - 01/11/91
Date: 11 Jan 91 23:06:58 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA. 
 
                    PIONEER 10 STATUS REPORT
                       January 11, 1991
 
     On January 6, following an IPP procedure where the instruments
were powered off, the 34 meter Goldstone station experienced antenna
problems.  As a result, commands to turn on the CRT and GTT instruments
on the Pioneer 10 spacecraft could not be sent until the next day.  On
January 7, a power failure at the 70 meter Goldstone station caused a
1 hour loss of telemetry data.  On January 8, CPA (Command Processor
Assembly) problems at the 70 meter Spain station prevented the
transmission of critical roll phase, stored command logic, and PA
instrument commands.  The commands were sent 15 hours later, during
the next scheduled support. 

      ___    _____     ___
     /_ /|  /____/ \  /_ /|
     | | | |  __ \ /| | | |      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 11 Update - 01/11/91
Date: 11 Jan 91 23:08:52 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA. 
 
                      PIONEER 11 STATUS REPORT
                         January 11, 1991
 
     Receiver switch attempts were made on Pioneer 11 spacecraft on
January 3 and 5, without success.  A precession maneuver has been
scheduled for January 11 over the 70 meter Spain antenna.  The
spacecraft was placed in engineering format on January 10 to allow
accurate uplink predicts verification during the tracking pass. 

      ___    _____     ___
     /_ /|  /____/ \  /_ /|
     | | | |  __ \ /| | | |      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 11 Update - 01/18/91
Date: 19 Jan 91 01:16:05 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA. 
 
                        PIONEER 11 STATUS REPORT
                            January 18, 1991
 
     A precession maneuver was performed by the Pioneer 11 spacecraft.
The maneuver was transmitted on January 11, and monitored on January
12.  Due to problems at the 70 meter Spain station, spacecraft
receiver lock was not observed.  Also, ground receiver AGC (Automatice
Gain Control) data, used to estimate the accuracy of the maneuver, was
also affected.  A number of commands associated with maneuver did not
execute, including a power off command for the CRT instrument.  This
caused the battery to come online during the pulse firing.  An AGC log
is being developed to track the ground receiver AGC to help determine
the success of the maneuver. 

      ___    _____     ___
     /_ /|  /____/ \  /_ /|
     | | | |  __ \ /| | | |      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 10 Update - 01/25/91
Date: 25 Jan 91 23:19:26 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA. 
 
                       PIONEER 10 STATUS REPORT
                          January 25, 1991
 
     On January 14, the reference frequency used by the DSS (Deep
Space Station) transmitters was lowered by 35 Hz for the Pioneer 10
spacecraft.  This is done periodically to to compensate for the lower
spacecraft receiver rest frequency brought about by the the changing
thermal environment.  On January 17, unpredicted RFI (Radio Frequency
Interference) at the 70 meter antenna at Spain caused a 1 hour and 14
minute loss of telemetry data. 

      ___    _____     ___
     /_ /|  /____/ \  /_ /|      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: Pioneer 11 Update - 01/25/91
Date: 25 Jan 91 23:21:21 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
  
                         PIONEER 11 STATUS REPORT
                            January 25, 1991
 
     Unsuccessful attempts to switch the receiver were made on January
16, 18, and 20 on the Pioneer 11 spacecraft.  Evidence from power
parameters has confirmed that the solenoid of the switch is actually
being pulsed, but the switch has not moved.  On January 18, unpredicted 
RFI (Radio Frequency Interference) at the 70 meter antenna at Spain 
caused a 31 minute loss of data. 

      ___    _____     ___
     /_ /|  /____/ \  /_ /|      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!

The ***SOLENOID*** on the switch???

Good grief.  We forget how old this thing is.

Burns

From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Pioneer 11 Update - 02/01/91
Date: 1 Feb 91 21:43:27 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA. 
 
                      PIONEER 11 STATUS REPORT
                        February 1, 1991
 
     Effective January 31 for the Pioneer 11 spacecraft, the command
idle modulation at the DSS's (Deep Space Stations) was changed to
zero's for both the Idle 1 and the Idle 2 states of the CPA (Command
Processor Assembly).  The radiation of all zero bits prior to the
first spacecraft command resets the decoder squelch logic that is
being randomly triggered by noise from the failed receiver.  It is
believed that this method prevents the frequent command failures that
have been experienced. 
 
     A new power sharing plan will be implemented on February 1.  
This will turn on the HVM and the TRD (Trapped Radiation Detector)
instruments for the month of February. 

      ___    _____     ___
     /_ /|  /____/ \  /_ /|      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!

  Can someone out there translate the status of PIONEER 11 into English?

  Is it still in trouble?

  Can it control it's orientation and keep pointed toward Earth?

  Can it be tracked but not commanded?

  Can it be commanded?

  Can it do any scientific work?

  George

>  Can someone out there translate the status of PIONEER 11 into English?

I can sure try.

>  Is it still in trouble?

Yup.

>  Can it control it's orientation and keep pointed toward Earth?

So far, it seems that way - but the situation is tenuous at best.

>  Can it be tracked but not commanded?
>  Can it be commanded?

Yes it can be commanded - but it isn't necessarily doing all the things
that is asked of it.  In particular, they would dearly love if it would
change the reciever it is using and it seems to either ignore the request or
it is unable to comply due to some mechanical failure.

Other subsystems, such as navigation and the instrument platform seem to
be working O.K.  Space probe design is highly modular and relatively loosely
coupled.  This allows them to have mega-problems in the communications subsystem
yet still allow science data to flow (albeit not in a way that matches the
operations requirements at this end).

>  Can it do any scientific work?

Absolutely.  I believe it still is.   The main problem is that the effort
required to keep it running and in any shape may exceed whatever returns
we get from it.   With a steadily increasing load on the DSN, trying to
keep this aging traveller alive and productive may not be possible much
longer.


All of the above is my interpretation of what I've read here and elsewhere
(some of which can obviously change with a single cosmic ray hitting the right
spot).

- dave

To be a bit more specific, it seems that there are two receivers, A and B.  B
is currently hooked to the hi-gain antenna, and A to the medium-gain antenna.
The biggest problem is that B has gotten very noisy.  When they use "coherant
mode", which I think means that the transmitter somehow locks to the receiver
signal, they can't transmit anything.  So they are using non-coherant mode for
transmissions (downlinks to the ground, that is).  In addition, since B can't
receive worth a darn, they have to mostly use receiver A.  However, the medium
gain antenna which A is connected to is "supposed" to be out of range.
Nontheless, if they blast 200KW at it from the ground, they can still get it
to receive for the time being.

They are trying to get receiver A hooked to the highgain, but that command
does not get executed for some reason.  It seems to be mechanical.

Questions which I can't answer:  Can receiver B do ANYTHING over the high gain,
or is it totally out of it?  How much longer before it cruises out of 200KW
range?  Will they try to increase the power beyond 200KW?  (200 seems to be
the current max).

Burns

A little background information... (a layman's interpretation)

Coherent communications employs a facility in the probe's communication
systems where the received signal's frequency is dropped by a specific
amount (and sometimes they muck with the phase a bit too).   Coherent
communications mean that the transmitter doesn't have to have a perfectly
working oscillator to transmit at a known frequency.   The primary purpose
of coherent communications allows very accurate doppler ranging of the
craft, since the doppler shifts are built into the system and can be very
accurately measured (phase mucking allows even more precise measurement).

Non-coherent communication depends on the probe's transmitter's oscillator
to provide the frequency base for the transmission.  Many things (temperature,
age, etc.) affect the oscillator so non-coherent communications are less
reliable -- assuming of course that you have a receiver.

I believe that when the term "lock" is used, it refers to the ability of
the ground station to accurately track the incoming frequency shifts based
on the outgoing transmissions.   When you consider that this is now typically
done by different DSN stations (since it can take 12 hours for a round trip
communication, the originating station is out of sight when the reply comes
back)!

I sometimes feel that the DSN is as much a technical marvel as the crafts
it tracks.

- dave

From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Pioneer 10 Update - 02/08/91
Date: 8 Feb 91 21:04:11 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA. 
 
                       PIONEER 10 STATUS REPORT
                         February 8, 1991
 
     Three sets of roll reference scans of the star Sirius, using the
IPP (Imaging Photopolarimeter) instrument, were made on January 25. 
On February 4, a power failure at 70 meter Goldstone station resulted
in a 37 minute loss of telemetry data.  During the same track, 2
commands were aborted at the DSS (Deep Space Station).  The numerous
command aborts that have been occurring at the DSS's are being
investigated by JPL. 

      ___    _____     ___
     /_ /|  /____/ \  /_ /|      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: Pioneer 11 Update - 02/08/91
Date: 8 Feb 91 21:05:48 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
  
                      PIONEER 11 STATUS REPORT
                        February 8, 1991
 
     Another unsuccessful attempt to switch receivers on the Pioneer
11 spacecraft was made on February 1.  There were no command rejects. 
The power sharing plan implemented on February 1 (HVM and TRD on) will
remain in effect for February and March 1991. 
 
     Work is continuing to develop a method to determine the
spacecraft pointing attitude (no attitude has been obtained since the
receiver failure). On January 9 an IPP (Imaging Photopolarimeter)
procedure will be transmitted which will obtain the the roll and cone
angles of Sirius and Canopus.  If sufficient data is obtained, the
intersection of the two cone angles may be used to determine the attitude. 
 
     From February 9 to 10, the spacecraft will be placed in format C
(engineering) to increase the sample rate of the telemetered receiver
lock status.  This will help determine the accuracy of the uplink predicts. 

      ___    _____     ___
     /_ /|  /____/ \  /_ /|      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: Pioneer 10 Update - 02/15/91
Date: 16 Feb 91 03:17:25 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA. 
 
                        PIONEER 10 STATUS REPORT
                          February 15, 1991
 
     On February 8 and 13, IPP (Imaging Photopolarimeter) procedures
were transmitted to the Pioneer 10 spacecraft to obtain three scans of
the star Sirius.  The data will be used to compute the spacecraft attitude. 

      ___    _____     ___
     /_ /|  /____/ \  /_ /|      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: Pioneer 11 Update - 02/15/91
Date: 16 Feb 91 03:18:43 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA. 
 
                       PIONEER 11 STATUS REPORT
                         February 15, 1991
 
     The February 9 IPP (Imaging Photopolarimeter) procedure to the
Pioneer 11 spacecraft was successful in obtaining roll and cone angle
measurements of the star Sirius.  The attempt to obtain data from
Canopus failed to produce sufficient data, and will be repeated on
February 16.  Attitude software used for Pioneer Venus to calculate
pointing is being modified to accept Pioneer 11 star angle data. 
 
     On February 10, the spacecraft mainfeed was offset to allow the
collection of ground receiver AGC (Automatic Gain Control) data.  The
high resolution engineering data received on February 10 has produced
accurate receiver lock times.  The data show that the receiver is
locking up 65 Hz below the predicted frequency.  The DSN (Deep Space
Network) predicts will be updated, accordingly. 

      ___    _____     ___
     /_ /|  /____/ \  /_ /|      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: Pioneers 7 and 8 Update - 02/11/91
Date: 23 Feb 91 04:28:03 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
  
                     PIONEER 7 and 8 STATUS REPORT
                         February 22, 1991
 
     The Pioneer 7 spacecraft was tracked for 4 hours on February 16. 
The CRD (Cosmic Ray Detector) and the PA (Plasma Analyzer) instruments
were turned on for 1 1/2 hours each. 
 
     Pioneer 8 was tracked on February 17.  Attempts to command the
spacecraft were unsuccessful.  Three attempts were made at an uplink
power of 18 kW.  Telemetry received during the pass is being analyzed
to evaluate the communications subsystem.  At the next tracking
opportunity the uplink power will be increased. 

      ___    _____     ___
     /_ /|  /____/ \  /_ /|      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: Pioneer 10 Update - 02/22/91
Date: 23 Feb 91 04:29:55 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA. 
 
                        PIONEER 10 STATUS REPORT
                           February 22, 1991
 
     On February 13, predicted RFI (Radio Frequency Interference) at
the Madrid 70 meter station caused a 2 hour and 11 minute loss of
telemetry data. Losses of 35 minutes and 48 minutes occurred on
February 14 and 18, respectively.  Command aborts by the CPA (Command
Processor Assembly) by three different antennas were experienced on
February 15, 19, and 20. JPL is continuing to investigate the apparent
failures at the stations. 

      ___    _____     ___
     /_ /|  /____/ \  /_ /|      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: Pioneer 11 Update - 02/22/91
Date: 23 Feb 91 04:31:43 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA. 
 
                        PIONEER 11 STATUS REPORT
                          February 22, 1991
 
     A second attempt to produce roll and cone angles of Canopus with
the IPP (Imaging Photopolarimeter) instrument on the Pioneer 11
spacecraft on February 16 was largely unsuccessful.  The instrument
appeared to lock on numerous objects, probably due to noise from the
high gain setting.  The data are being applied, together with data
from Sirius, to newly developed attitude software in an attempt to
obtain a spacecraft attitude. 
 
     Unsuccessful attempts to switch receivers were continued on
February 14 and 19.  All commands were successfully received by the
spacecraft, employing the new Idle-2 sequence of all zeroes,
implemented at the DSN (Deep Space Network). 

      ___    _____     ___
     /_ /|  /____/ \  /_ /|      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: Re: Pioneers 7 & 8 Update - 02/11/91
Date: 25 Feb 91 19:37:35 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
 
In article <1991Feb24.234136.1026@jarvis.csri.toronto.edu>
wayne@csri.toronto.edu (Wayne Hayes) writes: 

>In article <1991Feb23.042803.3404@jato.jpl.nasa.gov>
>baalke@mars.jpl.nasa.gov (Ron Baalke) writes:
>>
>>                     PIONEER 7 & 8 STATUS REPORT
>>                         February 22, 1991
>>  Attempts to command the
>>spacecraft were unsuccessful.  Three attempts were made at an uplink power of
>>18 kW.  Telemetry received during the pass is being analyzed to evaluate the
>>communications subsystem.  At the next tracking opportunity the uplink power
>>will be increased.
>
>I don't quite understand this.  Does "telemetry" require any active
>participation by the spacecraft?  I would have thought that in order to
>know precisely where the craft is (that's what telemetry is, right?)
>you would need a signal coming from it.  If that's the case, what
>is the problem?  Is it just mosying along saying "HERE I AM!" but not
>responding otherwise?
 
     Of all the spacecraft in the Pioneer 6-9 series, only Pioneer 9
is inoperative.   Useful scientific data (telemetry data) is still
being obtained from the other three spacecraft, though they are
tracked intermittently. Pioneer 6 is is the oldest surviving
spacecraft (launched in 1965), and is still in good shape.  On Pioneer
7, the role rederence is inoperative so no directional data is
available.  Also, the solar array is weak on Pioneer 7 so instruments
cannot be run at aphelion.  On Pioneer 8, the sensors work only near the 
Sun, so directional data cannot be obtained for the rest of the 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.

Date: 8 Mar 91 21:04:01 GMT
From: rex!wuarchive!sdd.hp.com!elroy.jpl.nasa.gov!jato!mars.jpl.nasa.gov!
      baalke@g.ms.uky.edu  (Ron Baalke)
Subject: Pioneer 8 Update - 03/01/91
  
                       PIONEER 8 STATUS REPORT
                          March 1, 1991
 
     The telemetry received from the Pioneer 8 spacecraft on February
17 has been reviewed, and the spacecraft status gives no indication of
a problem which could account for the failure to acquire the spacecraft 
receiver.  The next uplink opportunity will be made at a power level 
above 18 kW. 

      ___    _____     ___
     /_ /|  /____/ \  /_ /|      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 21:05:34 GMT
From: rex!wuarchive!sdd.hp.com!elroy.jpl.nasa.gov!jato!mars.jpl.nasa.gov!
      baalke@g.ms.uky.edu  (Ron Baalke)
Subject: Pioneer 10 Update - 03/01/91 
 
                          PIONEER 10 STATUS REPORT
                               March 1, 1991
 
     On February 20 and 25, predicted RFI (Radio Frequency
Interference) at at the Madrid 70 meter station caused a 55 minute 
and a 1 hour telemetry outage, respectively, with the Pioneer 10
spacecraft.  On February 22, antenna problems at the Goldstone 70
meter station caused a 47 minute loss of telemetry data. 
 
     On March 1, the Madrid 70 meter antenna was unable to lock up
telemetry at the predicted bit rate of 16 bits/second.  RFI was
present, however analysis of the signal by the station indicated the
spacecraft may have been transmitting at 64 bits/second.  The
Goldstone 70 meter antenna supported a short pass on the same day and
was also unable to lock to 16 bits/second, but reported the SDA
(Subcarrier Demodulator Assembly) was in-lock at 64 bits/second.  Ames
Research Center sent a bit rate change command back to 16 bits/second
to the spacecraft which will be executed on March 2. 

      ___    _____     ___
     /_ /|  /____/ \  /_ /|      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 21:06:58 GMT
From: rex!wuarchive!sdd.hp.com!elroy.jpl.nasa.gov!jato!mars.jpl.nasa.gov!
      baalke@g.ms.uky.edu  (Ron Baalke)
Subject: Pioneer 11 Update - 03/01/91 
 
                         PIONEER 11 STATUS REPORT
                             March 1, 1991
 
     The IPP (Imaging Photopolarimeter) instrument will be turned on on
the Pioneer 11 spacecraft on March 1 to allow it to warm up in preparation
for another scan of Canopus on March 2.  While the IPP is warming up, the
HVM instrument will be off.  At the request of the TRD (Trapped Radiation
Detector) experimenter, the telemetry format will be changed from "A" to "B".

      ___    _____     ___
     /_ /|  /____/ \  /_ /|      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: Pioneer 10 Update - 03/08/91
Date: 12 Mar 91 00:41:06 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA. 
 
                          PIONEER 10 STATUS REPORT
                               March 8, 1991
 
     For unknown reasons uncommanded changes have occurred on the
Pioneer 10 spacecraft along with the non-execution of commands
following a change to the IDLE 2 CPA (Comand Processor Assembly) mode
at the DSN (Deep Space Network).  This change, radiating continuous
zeros in IDLE 2, was originally implemented for Pioneer 11, and solved
the frequent command rejects for Pioneer 11.  For uniformity, this
mode was also implemented for Pioneer 10 on February 28. 
 
     Subsequent tracks on March 1 over Madrid and Canberra 70 meter
antennas, had receiver lock but could not lock up on the telemetry. 
The stations reported seeing 64 bits/second coded data in the SDA
(Subcarrier Demodulator Assembly), which was too high to achieve
telemetry lock.  Bit rate change commands were sent for 16
bits/second, and on March 2 good telemetry was received from the 70
meter Madrid station.  Indications are that a number of commands,
including the IPP (Imaging Photopolarimeter) configuration commands,
had failed to execute, and that uncommanded changes has occurred.  On
March 4, the IDLE 2 mode was changed to the original one and zero
non-radiating setting, and no problems have been experienced since. 
The connection between an idle transmit pattern and an uncommanded
change in the spacecraft is not yet understood. 
 
     On March 5, high winds at Goldstone caused a 1 hour and 22 minute
loss of telemetry. 

      ___    _____     ___
     /_ /|  /____/ \  /_ /|      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: Pioneer 11 Update - 03/08/91
Date: 12 Mar 91 00:42:58 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA. 
 
                            PIONEER 11 STATUS REPORT
                                  March 8, 1991
 
     Additional scans of Canopus were made by the Pioneer 11
spacecraft at lower gain settings on March 2, but again produced
multiple locks.  The data is being compared with previous data to see
if one of the contacts could be Canopus.  The 36-hour receiver switch
timer was re-enabled on March 2, in an attempt to cause a receiver
switch during long tracking gaps. 

      ___    _____     ___
     /_ /|  /____/ \  /_ /|      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: Pioneer 11 Update - 03/15/91
Date: 16 Mar 91 01:13:02 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA. 
 
                         PIONEER 11 STATUS REPORT
                            March 15, 1991
 
     Additional unsuccessful receiver switch attempt were with the
Pioneer 11 spacecraft made on March 7, 10, and 13.  Another IPP
(Imaging Photopolarimeter) procedure was sent on March 13 in an
attempt to get a reliable cone angle measurement of Canopus. 

      ___    _____     ___
     /_ /|  /____/ \  /_ /|      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: Pioneer 11 Update - 03/22/91
Date: 22 Mar 91 20:08:59 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
  
                           PIONEER 11 STATUS REPORT
                               March 22, 1991
 
     On March 17, the fourth attempt to obtain clock and cone angles
of Canopus with the IPP (Imagine Photopolarimeter) instrument was
unsuccessful.  Each attempt lowered the gain setting by one to reduce
the presumed triggering on noise, but the contacts do not appear to be
on Canopus.  On March 23 and 24 an attempt will be made to lock on the
star Vega. 

      ___    _____     ___
     /_ /|  /____/ \  /_ /|      Ron Baalke         | baalke@mars.jpl.nasa.gov
     | | | |  __ \ /| | | |      Jet Propulsion Lab | 
  ___| | | | |__) |/  | | |___   M/S 301-355        | Change is constant. 
 /___| | | |  ___/    | |/__ /|  Pasadena, CA 91109 | 
 |_____|/  |_|/       |_____|/                      | 

Ames Research Center will hold a press briefing for Bay Area reporters today to
commemorate the 20th anniversary of the Pioneer 10 spacecraft.  The 568- pound
spacecraft was launched from Kennedy Space Center aboard an Atlas- Centaur
rocket this day in 1972.  The spacecraft is now beyond the orbits of all the
planets, more than five billion miles from Earth, and exploring the region of
the Sun's extended magnetic field and electric field environment -- the
Heliosphere. Pioneer 10 was the first spacecraft to cross beyond the Asteroid
Belt and the first to fly by Jupiter -- providing the first flyby images of the
Solar System's largest planet.  Pioneer 10 is now the most distant
human-engineered object in space and has enough velocity to escape the
gravitational pull of the Sun. In the odd event that some other group of
interested beings ever finds it, Pioneer 10 carries a plaque which shows a
representation of a man and a woman standing beside a likeness of the vehicle.
The plaque, using a visual and binary code, also depicts our solar system as
being the origin point for the spacecraft's journey.  A videotape of Pioneer 10
events, including recent discoveries, will be shown on NASA Select television
today at 1:30 pm EST. Three of NASA's four deep space vehicles are heading
towards the center of our galaxy, the Pioneer 10 is heading in the opposite
direction.  All four are beyond Pluto (which is presently inside the orbit of
Neptune). This three-dimensional spacecraft arrangement will help the space
physics community in their continuing search for the edge of the Sun's
influence -- the heliopause -- and true interstellar space.

-----------------------{ Press Release Follows }---------------------------------

Paula Cleggett-Haleim
Headquarters, Washington, D.C.                   February 28, 1992

Peter Waller
Ames Research Center, Mountain View, Calif.

NOTE TO EDITORS:  N92-16


     A  status briefing to mark the 20th anniversary of Pioneer
10's launch will be held Monday, March 2, at 1 p.m. EST at Ames
Research Center, Mountain View, Calif.  The briefing will include
new science and past accomplishments of the spacecraft, whose
signal will be "piped in" to the briefing from 5 billion miles
away.  Also featured will be a launch-identical, full-scale
replica of Pioneer 10 shown for the first time.

     Briefers are Richard Fimmel, Pioneer Project Manager; Dr.
Palmer Dyal, Project Scientist; and Charles Hall, original Project
Manager.

     Pioneer 10, which has been exploring space for 20 years, was
the first spacecraft to cross the Asteroid Belt, the first to
visit Jupiter and is now the most distant human-made object in
space, making discoveries about the limits of our solar system.

     A television program about Pioneer 10 using some materials
from the briefing (interviews, animation, etc.)  will be shown at
1:30 p.m. EST, March 2, on NASA Select TV, Satcom F2R, Transponder
13, at 72 degrees west longitude, frequency 3960 MHz, audio 6.8
MHz.
 

Article: 1849
From: clarinews@clarinet.com
Newsgroups: clari.tw.space,clari.news.military,clari.news.aviation
Subject: Pioneer 10 celebrates 20 years of exploration
Date: 2 Mar 92 21:45:29 GMT
 
	MOUNTAIN VIEW, Calif. (UPI) -- NASA's Pioneer 10 probe,
launched 20 years ago Monday and now 5 billion miles from Earth, is
still dutifully exploring the heavens as it sails away into the
uncharted depths of interstellar space. 

	Launched March 2, 1972, by a powerful Atlas-Centaur rocket,
Pioneer 10 was the first spacecraft to pass through the rocky asteroid
belt beyond Mars and the first to fly past mighty Jupiter, a historic
flyby Dec. 3, 1973, that provided the first closeup view of the solar
system's largest planet. 

	After sailing past Jupiter, Pioneer 10 headed away into deep
space and currently is the farthest man-made object from Earth, so far
that radio signals, traveling at 186,000 miles per second, take 7 1/2
hours to reach the spacecraft. 

	``Basically, the spacecraft is performing quite well,''
Pioneer mission manager Richard Fimmel of NASA's Ames Research Center
said in a video presentation Monday. ``Seven of its (12) instruments
are still performing well, its various subsystems are working and it
is transmitting good, solid, error-free data to Earth all the time.'' 

	Like all of America's deep space programs, Pioneer 10 is
powered by two radioisotope thermoelectric generators, compact
powerpacks that use the heat produced by the radioactive decay of
plutonium to generate electricity. 

	At launch, the RTGs generated about 120 watts of power. But
the electrical output has decreased as fuel has been exhausted and by
the time Pioneer 10's radio signal reaches Earth, it is far weaker
than the power source of a typical digital watch. 

	But using giant antennas and sensitive electronic gear, NASA
engineers still take in data from the hardy craft as it sails toward
the boundary between the solar system and interstellar space. 

	That tenuous boundary is defined by the limit of the sun's
ability to directly affect the space environment through the solar wind, 
a stream of atomic particles blasted away from the sun's atmosphere. 

	``Our main goal now in the mission is to penetrate the
boundary, or the terminal region between our sun's hot gas, known as
the heliosphere, and the interstellar medium,'' said Pioneer project
scientist Palmer Dyal. ``This medium has only been studied remotely by
telescopes, which are far less accurate than the ... measurements we
plan to make with our Pioneer spacecraft.'' 

	Pioneer 10 currently is sailing out of the solar system at
about 28, 900 mph. It passed the orbits of Neptune and Pluto years
ago, but it will not encounter another heavenly body for another
32,610 years or so when it sails past a star known as Ross 248. 

	``It is the first spacecraft to exit the solar system in the
sense that it's beyond all the planets,'' Fimmel said. ``Pioneer 10
has been just a fantastic mission, breaking new ground all the way.'' 

	Pioneer 10 was the first of four American probes launched to
explore the outer planets. Pioneer 11, identical to its sistercraft,
was launched April 5, 1973. Passing by Jupiter in December 1974 and
Saturn five years later, Pioneer 11 also is heading out of the solar
system and still returning useful data. 

	NASA engineers built on their experience with the Pioneer
spacecraft to build the more sophisticated Voyager probes that
explored Jupiter, Saturn, Uranus, and Neptune in unprecedented detail
between 1979 and 1989.  All four spacecraft continue to beam back data
from deep space. 

Article: 28543
Newsgroups: sci.space,sci.astro
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Subject: Pioneer 6 Update - 11/11/92
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Date: Thu, 12 Nov 1992 01:08:36 GMT
 
                            PIONEER 6 STATUS REPORT
                              November 11, 1992
 
     Yesterday, the Deep Space Network's 70 meter antenna in Goldstone,
California supported a tracking pass of the Pioneer 6 spacecraft.  Receiver
lock was attained, but we were unable to attain telemetry lock because no
subcarrier was detected.  The expected bit rate was 16 bps uncoded telemetry.
The AGC (Automatic Gain Control) was initially at -175.3 dbm, but was seen to
fluctuate causing the receiver to toggle in and out-of-lock.  The problem is
under investigation.
 
     Pioneer 6 was launched on December 16, 1965 and is the oldest surviving
spacecraft.  Pioneer 6 was last supported on December 16, 1990, on the
25th anniversary of its launch, and no problems were encountered then.

     ___    _____     ___
    /_ /|  /____/ \  /_ /|     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 2490 of sci.space.news:
Newsgroups: sci.space.news
Path: nntpd2.cxo.dec.com!nntpd.lkg.dec.com!news.crl.dec.com!deccrl!caen!saimiri.primate.wisc.edu!ames!dont-send-mail-to-path-lines
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Subject: Pioneer 6 Update - 11/19/92
Message-ID: <1992Nov19.221627.24564@news.arc.nasa.gov>
Followup-To: sci.space
News-Software: VAX/VMS VNEWS 1.3-4   
Keywords:  Pioneer 6
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: Fri, 20 Nov 1992 06:15:58 GMT
Approved: sci-space-news@ames.arc.nasa.gov
Lines: 20

                             PIONEER 6 STATUS REPORT
                                November 19, 1992

     Attempts to obtain solid lock on the telmetry signal from the Pioneer 6
spacecraft continue to be unsuccessful.  Yesterday, the receiver of the 70
meter antenna in Goldstone, California, was able to lock up on the spacecraft's
signal, but no telemetry lock was acquired.  The station was reconfigured for
low noise but still no telemetry lockup was occuring.  Uplink acquistion was
performed using the high power transmitter and the spacecraft was command
to 8 bps uncoded telemetry.  This showed some improvement, but the telemetry
signal kept toggling in and out of lock.  Througout the tracking pass that
lasted over 3 hours, the station was unable to maintain a solid lock on
the telemetry signal.
     ___    _____     ___
    /_ /|  /____/ \  /_ /|     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.

Paula Cleggett-Haleim
Headquarters, Washington, D.C             June 11, 1993

Peter Waller
Ames Research Center, Mountain View, Calif.

RELEASE:  93-110

        The most distant manmade object, Pioneer 10, on Sunday celebrates the
10th anniversary of becoming the first spacecraft to explore beyond the orbit
of Pluto, currently the most distant solar system planet discovered.

        Pioneer 10 continues to send back science data to Earth even though the
spacecraft is 5 1/2 billion miles from its home planet.  It takes more than 8
hours for Pioneer 10's radio signal to make the trip to Earth.

        Pioneer 10 left all the known planets behind on June 13, 1983.
Launched in 1972, the 570-pound spacecraft had a design life of 21 months.
More than two decades later, it continues to hurtle through deep space at close
to 30,000 miles per hour.

        Five of the 11 instruments aboard are still sending back data through
the spacecraft's 7 1/2 watt radio signal, about the strength of a home
nightlight.  Pioneer 10 has transmitted more than 170 billion bits of science
data.  By the time its signal reaches the football-field-sized antennas of
NASA's Deep Space Network, the signal has the strength of 4-billionths of a
trillionth of a watt.

        During its long life, Pioneer 10 has scored a number of firsts -- the
first spacecraft to cross the asteroid belt; to fly by Jupiter and return
pictures; to chart Jupiter's intense radiation belts; to measure the mass of
its four planet-sized moons; to locate the giant planet's magnetic field and to
discover that Jupiter is predominantly a liquid planet.

        As it plows through unexplored space, Pioneer 10 continues to seek the
boundary between the solar wind and true interstellar space, to search for
evidence of a possible 10th planet and for gravity waves confirming Einstein's
Theory of Relativity.


        Events such as collisions between entire galaxies would "rattle" the
actual structure of space itself, producing gravity waves.  The waves may be
relatively easy to detect in the long wavelengths (1 billion to 5 billion
miles).

        "Pioneer 10 and its sister ship, Pioneer 11, have been two of the
greatest scientific successes of the Space Age," said Dr. James Van Allen of
the University of Iowa, a Pioneer principal investigator.

        Perhaps Pioneer 10's most important finding about the outer solar
system is the extent of the sun's atmosphere, originally thought to have ended
at the orbit of Jupiter or Pluto. Pioneer 10 is now almost 10 times that far
and still within the solar atmosphere.  Many scientists now say that the solar
wind boundary interface with the cosmic interstellar gas might be as far away
as 9.3 billion miles, compared to Earth's distance from the sun of 93 million
miles.

        "Pioneer 10's exploration of the outer heliosphere (sun's atmosphere)
and its interface with the interstellar gas is of fundamental scientific
importance," said Dr. Frank B. McDonald of the University of Maryland,
Principal Investigator for the cosmic ray telescope. "By lasting so long,
Pioneer 10 has in essence created a new science mission and represents a
triumph for American technology and industry."

        "We still take science data from it daily and will probably continue to
do so until at least 1998.  That's an out-of-this-world record of
accomplishment," said Richard Fimmel, Ames' Pioneer 10 Project Manager.

        Pioneer 10 is managed by NASA's Ames Research Center, Mountain View,
Calif., and was built by TRW, Redondo Beach, Calif.

Pioneer 10 & 11 Status

UPDATED: 9/1/95 

Pioneer 10 

(Launched 2 March 1972) 

   Distance from Sun: 63.00 AU 
   Speed relative to the Sun: 12.5 km/sec (27,962 mph) 
   Distance from Earth: 9.44 billion kilometers (5.86 billion miles) 
   Roundtrip Light Time: 17 hours, 30 minutes 
   Active Instruments: 
      Plasma Analyzer 
      Charged Particle Instrument 
      Cosmic Ray Telescope 
      Geiger Tube Telescope 
      Ultraviolet Photometer 

The spacecraft is healthy and continues to make valuable scientific
observations in the outer regions of our Solar System. 

The maneuver on August 6 terminated itself after a few pulses when the
spacecraft sensed that the antenna beam was within the 0.3 degree dead-band
(within 0.3 degrees of center). A second maneuver, planned for August 27,
has been canceled. We anticipate that the signal will not degrade too severely
as the Earth moves out of the center of the beam. By mid-October, the
motion of the Earth will move it back into the center of the spacecraft
antenna beam. In December or January, we will have to maneuver again to
keep up with the Sun's and Earth's motion. 

Pioneer 11 

(Launched 5 April 1973) 

   Distance from Sun: 43.88 AU 
   Speed relative to the Sun: 12.24 km/sec (27,380 mph) 
   Distance from Earth: 6.50 billion kilometers (4.04 billion miles) 
   Roundtrip Light Time: 12 hours, 3 minutes 

The Pioneer 11 spacecraft is healthy at the moment, but the available
spacecraft power has declined to the point where its is insufficient for the
operation of any of the scientific instruments. Furthermore, the spacecraft
can no longer be maneuvered to point it's antenna accurately toward the
Earth, resulting in significant data losses. Since it cannot provide scientific
data anymore, the spacecraft will no longer be operated on a regular basis.
Instead, engineering data from the spacecraft will be collected periodically to
study the performance of the electronic subsystems under low-power
conditions. 

Project Manager: Fred Wirth
(e-mail:Fred_Wirth@qmgate.arc.nasa.gov) 

    I thought the following was worth passing on...

    Science News, Oct 14

    Farewell to a Pioneer

    It ventured within 42,000 kilometers of Jupiter's cloud tops,
    discovered a new ring and two moonlets of Saturn, and flew
    high enough above the sun's equatorial plane to detect the
    true character of the solar magnetic field. Now, after exploring
    the solar system for nearly 22 years and 6.6 billion km, the
    Pioneer 11 spacecraft has begun dying a slow death. Hurtling
    beyond Pluto into the far reaches of the solar system, the
    craft can no longer power its detectors, explains project
    manager Fred Wirth of NASA's Ames Research Center in Mountain
    View, Calif.

    Although NASA stopped daily communication with the aging craft 
    on Sept 30, it will tune in to Pioneer 11's fading radio signals
    for about 2 hours every 2 to 4 weeks through late 1996. Around
    that time, the crafts transmitter "will fall silent and Pioneer 
    11 will travel as a ghost ship in our galaxy" says Wirth. 
    Listening to the craft's swan song, he adds, may enable researchers 
    to prolong by a few months the service of its sister craft, Pioneer
    10, which now lies nearly 9.4 billion km from Earth.


    Dave
    

    re .*
    
    I heard on the radio this morning that Pioneer 10 is being retired
    (instruments switched off and no longer tracked). At this time it would
    be the spacecraft that is furthest away from us although it would
    appear that Voyager 1 will one day be further (but not within its
    operational lifetime).

    Well, not so much switched off, more to just fade away !
    
    It has just made it's 25th year in space ( March 2nd 1972 launch ), and
    the broadcasts are extremely weak now.
    They (NASA?) will be monitering it every so often, but I don't think
    any reliable data is coming from it.
    
    Distance is about 6 billion miles from home, and when we invent warp
    drive, NASA will send out a maintenance crew to recharge the batteries.
    
    :-)
    	Tom.

re .82
    
>    Well, not so much switched off, more to just fade away !
    
    Generally speaking with these probes the functionality exists to switch
    each of the instruments on and off independently. As of the last status
    report (in this conference) three instruments were actually switched on
    for some part of the time and producing good data but there seemed to
    be insufficient power to support that configuration. I think NASA is
    specifically deciding to switch off all the instruments. Perhaps this
    would allow special purpose use again in the future if NASA wanted to
    e.g. by allowing the weakened RTG output to charge the battery fully and
    then switch on an instrument and use it until the battery is flat and
    then repeat the scenario intermittently.