Conference 7.286::space

Why fly to Jupitor to send a probe into the sun?  Why not just send the 
fire portion of the probe to the sun from earth?

Rich

    Rich,
    
    The answer lies in the fact that the satelite gets a gravity assist to
    its speed in flying past jupiter.
    
    It requires considerable braking for a satelite launched from the earth
    to hit the sun.  By using the essentially free energy that is
    obtainable from a jupiter flyby, a much larger satelite can be
    launched.
    
    In essence, it takes somewhat longer, but you can do vastly more.
    
    Then after scoping out the requirements for the "fire" portion and
    determining the size of spacecraft needed and comparing that to the IUS
    (the upper stage for shuttle based launches), for lack of my knowing a
    better term, "throw rate" they determined that 800 (either lbs or kg)
    was left over for another purpose.  The only planet yet to be viewed
    close-up is pluto, hence the ice mission.
    
    Personal opinion:  I really think a flyby of pluto is a waste.  By
    2015, when the flyby is scheduled for, we should have EXCELLENT
    telescopes in space (I imagine the space telescope will be just the
    first of many space telescopes, due to the inherent advantage of
    viewing without atmospheric interferrance).  Such telescopes should be
    able to resolve pluto almost as well as a fly-by could.  Any planetary
    exploration after the advent of the space telescope should be either a
    lander or an orbiter, which can provide some longer term information
    gatherring, not a fly-by which is a one shot deal.

    re .-1
    
    How many here think the HST could see a volcano plume on Triton?
    
    In any case, you have forgotten that there are lots of other
    things normally done besides taking pictures.  At the very least,
    even the simplest probe can conduct "radio-science" experiments which
    determine a great deal about the density and composition of a planet's
    atomosphere.
    
    Burns
    

    Re:<<< Note 565.3 by DECWIN::FISHER "Burns Fisher 381-1466, ZKO3-4/W23" >>>
    
    >How many here think the HST could see a volcano plume on Triton?
    
    Actually I heard that the HST is supposed to have a resolving power
    sufficient to equal the quality of the voyager pictures at saturn.  I
    assumed that by 2015, when the ice mission is due to arrive at pluto,
    we will have large/better telescopes than HST (it is after all 25 years
    away).
    
    Also, I would not object to a pluto ORBITER, I just think a fly-by is
    no longer appropriate for objects within our solar system.  We have
    gotten enough "first shots" at most things within our solar system that
    only a longer term, more detailed visit should be undertaken.
    
    Tony

    Re: The last few
    	First I want to address the potential planet observing capabilities
    of the HST. Below is the best resolution expected from HST with the
    best typical resolution for ground based telescopes.
    
    
    	Planet				Best Resolution
    				    HST			Ground Based
    
    	Mars			   8 miles                90 miles
    	Jupiter			  85 miles               900 miles
    	Saturn			 175 miles              1900 miles
    	Uranus			 370 miles              4000 miles
    	Neptune			 590 miles              6500 miles
    	Pluto (near 2000)	~600 miles             ~6500 miles
    
    	HST would barely be able to resolve Pluto as a disk never mind see
    any detail. Using the recent Pluto/Charon occultation data plus some
    fancy processing of HST spectrographic data it may be possible to
    construct a map of Pluto with a 100 mile resolution but this still is
    no where near as good as the sub-kilometer resolution images one could
    obtain from a flyby mission.
    	In order to obtain visible light images of Pluto from Earth with a
    resolution of 1 kilometer, a telescope would need an aperture of over
    1.5 MILES! That size telescope simply won't be possible in the
    forseeable future. It has taken 20 years to get just one HST and it seems
    unlikely that there will be another comparable space telescope launched
    in the next 25 years never mind a bigger one.
    	The "Ice" portion of the Fire and Ice mission gives the most
    realistic possibility of veiwing Pluto close up for many years to come.
    Sending an orbiter or lander to Pluto is pretty tricky at this time.
    First off from the political point of view, no one in DC would be
    willing to spring for the couple billion dollars it would cost for such
    a mission. And yes it would cost that much...
    	On the technical side, Pluto would be a very fuel expensive planet
    to orbit. If a spacecraft is to get to Pluto in a reasonable amount of
    time, it would end up approaching Pluto at a speed in excess of 10
    km/sec. Since Pluto has such a weak gravitational pull, virtually all
    that velocity would have to be removed to enter orbit around it (as
    compared to the 1 or 2 km/sec needed by Galileo, Viking, Magellan,
    etc.). I'm not going to bother to do the detailed calculations now but
    a delta-V of 10 km/sec would require a propulsion system that would
    take up the majority (like 90%+ majority) of the mass sent to Pluto.
    This means that a one ton orbital payload would need over 10 tons of
    rocket just to get it into orbit (and probably another 100 tons of
    rocket to get it started from Earth to begin with!).
    	We could pull some tricks to decrease the propulsion needs like use
    aerobraking but we don't know for sure how dense Pluto's atmosphere is.
    We think we know just like we thought we knew how dense Triton's
    atmosphere was (Voyager 2 showed that it was 1/1000 as dense as
    expected). Only a spacecraft can tell us for sure.
    	Only a flyby mission to Pluto makes sense at this time. Only after
    we know the most basic facts about Pluto can some intelligent plans for
    future exploration (e.g. orbiters, landers, etc.) be formulated.
    
    				Drew         
    
    	

One point in favour of flyby missions to the outer planets, assuming they are
designed to operate for a significant time after the flyby, is that they
continue out of the solar system and can provide useful data about the outer
limits of the sun's influence, the heliopause and interstellar space.

There are currently four active US probes heading out of the solar system. Given
that the approved planetary missions are all orbiters, it could be 25-50 years
before further US probes leave the solar system.

gary

  You guys have said some good things, but you are not listening to each
other (or at least you are not reading each other carefully).

  Tony has pointed out that he feels telescopes will be better than the HST
25 years from now. Several have replied with numbers about the HST.

  Tony, you have missed the comment that there are other things in a
fly by besides the pictures of the planet. There are other devices that
measure things, there are pictures taken from behind the planet that
show features like the atmosphere and rings that only show up with back
lighting, and the gravitational effects can be measured by tracking the
position of the space craft has it passes the planet and its moons.

  You all have good ideas, but try to listen to each others ideas a
little better.

  George

    Yep, I'm guilty of ignoring the point about other things that a fly-by
    can discover.  I really am not sure that a pluto fly-by in 25 years is
    going to add all that much (anything?) to our knowledge of the solar
    system.
    
    I am not, I think guilty of over estimating the value of spaced based
    telescopy.
    
    Mr. Lepage has stated that to resolve Pluto with an accuracy of
    sub-kilometer resolution would require an aperature of 1.5 miles.  I
    take him 100% at his word, his comments are always appreciated for
    their completeness, accuracy and depth of information.  So where does
    that leave us?  We all know a 1.5 mile telescope is impossible, or is
    it? 
    
    I have heard of serious proposals that we could/should be able to do
    with optical astronomy what we are now starting to do with radio
    telescopy, that is combine the output of several individual telescopes
    to mimic one telescope with a much larger aperature.  There already
    exists the multiple mirror telescope in Arizona, a relatively small
    telescope that uses an array of samll telescopes to mimic a much larger
    telescope.  I think that improved computer control and enhancement
    techniques, sure to be available 25 years from now, should easily
    permit several hst sized telescopes to combine and ACT as a much larger
    telescope, perhaps with an effective aperature of much greater than 1.5
    miles, perhaps not, I really don't know.
    
    You must remember that the ice portion was assumed to cost some, what
    200 million?  This is not THAT big, but I sure think it would be better
    spent on another optical space telescope and the software/hardware
    necessary to make large virtual telescopes.  Such a telescope would
    tell us lots about pluto and the other planets AND about the rest of
    the universe.
    
    Another possibility that I might consider as a good use for the ice
    mission is a collision with pluto.  This would at least tell us
    something about the surface of the planet and we MAY be able to design
    a hard lander that could survive (I have heard talk of using hard
    landers on Mars as a really cheap mars landind mission).
    
    If we want another probe to the reaches beyond the solar system, if we
    assume that the voyagers and the pioneers will no longer be returning
    us data in the 21st century, lets design a interstellar space probe,
    not a pluto fly-by.  Such a probe might not head in the direction of
    pluto, we could pick the best direction to reach the cometary halo,
    discover the tenth planet or nemesis or whatever.  Perhaps we could
    afford several of these simpler craft (without telescopes?) for the
    same $ and weight budget of a pluto fly-by.  This could be a much
    better investment.
    
    I don't want anyone to think that I am against exploration, I am 100%
    for it, I just want to use what we have to maximize our exploration.
    
    Tony
                      

        Current JPL policy regarding planetary exploration is to send a 
    flyby mission first, then an orbiter with a possible lander as well.
    The other spacefaring nations and organizations may not have such
    a plan.

        There is a probe on the JPL drawing boards which is designed
    specifically to explore the regions of interstellar space where the
    Oort Cloud of comets is theorized to exist.  The probe is called TAU,
    which stands for Thousand Astronomical Unit, which is how far TAU will
    travel from Earth (one Astronomical Unit equals approximately 150
    million kilometers/93 million miles, the mean distance from the Sun to
    Earth).  The craft, which may be launched by the year 2050, will take
    fifty years to reach its destination. TAU will also be carrying a
    Pluto probe to be sent to the tiny world, either as a flyby mission
    or an orbiter (possibly even a lander as well). 

        You can find more details on TAU in the ASTRONOMY Conference 
    Topic 193 (press the KP7 or SELECT key to add ASTRONOMY to your 
    Notebook), plus even more information on TAU and other possible 
    starships in THE STARFLIGHT HANDBOOK:  A PIONEER'S GUIDE TO 
    INTERSTELLAR TRAVEL, by Eugene F. Mallove and Gregory L. Matloff, 
    John Wiley & Sons, Inc., New York, 1989, ISBN 0-471-61912-4 
    (hardcover - $19.95).

        Larry

    Re:.8
    	I've read about what is basicly an optical version of a synthetic
    aperture telescope. The concept is being seriously studied in the US
    and Europe. One of the best proposals (and one that could make a
    synthetic aperture of 1.5+ miles to observe Pluto) is to use three
    satellites in Earth orbit. One would be at the center controlling and
    collecting light from the other two satellites (which would have small
    telescopes) as they slowly spiral towards and away from the center.
    Apertures of a couple to a couple of tens of miles (with resolutions as
    great as 2 MICRO arc seconds) could be generated with the satellite
    measurement and control technology that should be available around the
    turn of the century.
    	The problem with observing Pluto with such a telescope is that the
    observations would take many hours and in the case of Pluto (as well as
    the other planets) the longitudinal information would be smeared
    greatly reducing the resolution of the image. The same thing happened
    with the recent VLA radio observations of Saturn.
    	Of course there are always solutions to such problems. As long as
    Pluto had no temporally varying features (e.g. clouds or haze) and we
    knew its period of rotation and direction of its rotational axis to
    better than one part in 10,000 it should be possible to make a high 
    resolution map of Pluto from Earth. The problem would be (even with this 
    solution) that several weeks of continuous observation would be required 
    and the data reduction would need a supercomputer far beyond what we have 
    now. At least its a possibility!
    	In the mean time, a flyby mission is still a good buy (for reasons
    that others have mentioned.
    
    				Drew
    
                

    re .10
    
    Only one thing:
    
    >	In the mean time, a flyby mission is still a good buy (for reasons
    >that others have mentioned.
    
    The problem is that "in the mean time" means before 2013.  I really
    don't think a pluto fly-by in 25 years will add much to our knowledge.
    
    Notice, I whole heartedly approve of the fire portion of the mission. 
    I think we can learn a lot by putting a probe in the solar carona
    (sp?).
    
    Perhaps a Pluto collision mission is also something I could get excited
    about, but not a fly-by.
    
    Tony

  I'd be in favor of the fly-by for a few reasons. First, even though it's
technically possible that we may have better telescopes by then, it is not a
financial certainty. Big scopes and these computer controlled multiple scope
arrangements sound expensive. 

  Second, these fly-bys seem to be able to do things like measure the
temperature and chemical composition of the atmosphere. 

  Third, they can measure the magnetic field.

  Fourth, the back lit pictures of the atmosphere and/or rings are always
interesting.

  Fifth, by observing the flight path through the planet system, it is possible
to get exact measurements of the gravitational effects of the planet and moons.

  Since the probe is not expensive and since it can do these things that
can't be done otherwise, I'd vote to send the probe.

  George

    Re:.11
    	Why a collision? The potential data return from a collision (in
    terms of quality and quantity) would be much less than with a flyby.
    In a collision all of the data (especially in the last couple of hours
    closest to Pluto) would have to be sent back live. In a flyby a lot
    more data could be gathered and recorded for later playback. The best
    pictures taken by Voyager 2  of Neptune and Triton were recorded and
    played back a day later.
    	In a collision, the last complete picture would have to be taken at
    an altitude of a couple thousand kilometers (assuming that the
    spacecraft had similar communication capabilities as Voyager). After
    that one last picture, SPLAT!. In a flyby you could take (and record)
    possibly several pictures at this altitude and still survive to take
    backlighted pictures of Pluto limb looking for hazes or rings. It would
    also allow for additional post-encounter navigation pictures to be
    taken which when combined with the radio tracking data can give a lot
    of information about Pluto's (and possibly Charon's) mass and mass
    distribution. In an impact mission you can't do that.
    	Speaking of radio, in a flyby mission the radio can be used to
    probe Pluto's atmosphere, TWICE!. In an impact mission you could make
    direct measurements (which would be great) but only at one point and
    after less than 30 seconds of measuring, SPLAT!
    	No UV solar occultation soundings could be made of Pluto in a
    collision. No darkside IR temperature measurements could be made in a
    collision. Terrific sun side particle and feild measurements could be
    made in a collision but then SPLAT! No down stream measurements could
    be made.
    	I don't understand your fascination with creating a new crater on
    Pluto. To prove we can do it? News flash: WE CAN! Voyager came within a
    few kilometers of its intended target at Neptune. If JPL can do that,
    they can hit a 1,900 kilometer in diameter Pluto. Is it the thrill of
    screaming towards the surface of a planet at 10 km/sec? If you really
    want to see what it would be like, take the pictures from the flyby
    mission and computer process them to simulate a collision.
    	A collision mission with Pluto especially after over a decade
    travel time would be nothing more than a cheap stunt with limited
    scientific return. It would be a sad day in this country if we have to
    resort to sensationalism just so we can get money for a mission. A flyby 
    mission offers a much better and richer return of data on Pluto. I 
    personally find that exciting. If you find it boring I geuss we have a 
    simple difference in opinion.
    
    				Drew
    
     

    Well, my reasons for a collision are perhaps not well thought out.
    
    I was thinking that there is a chance, that if we can design a probe to
    survive the g's that will occur with the Jupiter atmospheric probe and
    some of the R&D on penetrating ICBM warheads that it might be feasible
    to create a colliding probe that could survive and return long-term
    pluto data.  Data like chemical composition, temperature, etc.
    
    Also, if the probe were able to survive, it might be able to provide a
    similar quantity of optical data to a fly-by.
    
    I guess my reservation to the ice mission is that I view pluto as
    basically the same as triton.  Not really something from which we can
    learn a lot more.  I think our next bit of exploration should be
    elsewhere.  I find the asteroids and the comets much more interesting,
    and we haven't even touched them.
    
    I think a solar-electric ion propulsion satelite to visit SEVERAL
    asteroids would be FAR more exciting and potentially useful than some
    information on pluto, which might just duplicate our info from triton.
    
    I once tried to estimate the economic value of just one medium sized
    asteroid.  There are roughly 100,000 asteroids with volume greater than
    1 cubic mile.  As I understand it, there are at least 5000 nickel steel
    asteroids in the belt.  The value of one cubic mile of nickel steel is
    6 trillion dollars.  Now for me, using spaced based resources to
    completely irridatate an relatively environmentally hazardous (mining,
    transportation and forming of iron/steel) earth industry, by totally
    undercutting the price is a very exciting use for space!
    
    I really think we should explore and categorize the belt as our next
    (after gaelio, cassini and ulysses) priority for deep space
    exploration.  This could lead to schemes for moving asteroids to
    somewhere in earth's vicinity.
    
    Tony
                             

    (Tongue firmly planted in cheek)
    
    Why spend the money to do a fly-by of Pluto?  In fact, I don't see
    why we spent the money to even keep the Pioneers and Voyagers working.
    After all, isn't theory good enough?  Arm-chair science is so much
    more cost-effective!  We figured that the heliopause was somewhere
    between Saturn and Uranus, and sending those probes has only resulted
    in an expensive mission to find out where it really is!  We figured
    Neptune was going to be as atmospherically boring as Uranus, and
    instead, people have to do some real work now to figure out what
    drives Neptunian weather.  Now, since some scientists have decided
    that Triton is a good analog for Pluto, let's save money and not
    both to take the chance that they are wrong!
    
    (Tongue out of cheek.  Man, it's painful talking that way!)
    
    Let's satisfy everybody (except the cynics, who know the price of
    everything, and the value of nothing).  There have been plans on
    the drawing boards for penetrator probes for the moons of Mars,
    the asteroids, so why not the same for Pluto in addition to the
    fly-by?  These probes are designed to be released and fired into
    the particular astronomical body, relaying information back to the
    mother probe that carried them, where the information is then relayed
    back to Earth.  These are nothing as fancy as the entry probe that
    Galileo is carrying to Jupiter, but will provide information regarding
    surface composition, hardness, etc.  While these don't make sense
    for gas-giants, they seem ideal for rocky planets.  Since we're
    going there, why not?  Also, send the probe between Charon and Pluto,
    hit both with the penetrator probes, and see if the two bodies really
    do share an atmosphere (a wild idea I read about - purely speculative).
    Let's get a bang for our buck!
    

You guys are all wet and totally missing the boat.  If NASA had 800 lbs of 
payload weight left over what they should have done was advertise space on 
the payload for people's ashes, say at $5,000 a pinch.  Then they could 
raise a whole bunch of funds by launching a pinch of this guy and a pinch 
of that guy into the wild black yonder or the firey grave of Old Sol.  

Ya gotta remember that we ain't goin' nowhere until we make this business 
profitable in the short term.  :-)

Entrepreneurly yours,

Rich

    Re: Penetrators & Landers
    	I agree that sending a penetrator to Pluto or even better yet a
    lander would be terrific! However, it would really be premature to do
    it on the first mission to that planet. A penetrator (and even more so
    with a lander) needs to be slowed down before impact. Even a penetrator
    will disintegrate into a million pieces with an impact speed of more
    than a couple hundred mph (depending of the surface type). With the high
    approach velocity (>10 km/sec) expected for the ICE probe, rocket braking 
    would be impractical due to the weight. The best means of braking
    without use of a rocket would be to use aerobraking (i.e. using Pluto's
    atmosphere to slow down). The major problem with this suggestion is
    that we do not know enough about the density of Pluto's atmosphere to
    design an aerobrake. Only AFTER the initial flyby mission will we know
    enough about the atmosphere of Pluto to design penetrators, landers and
    aerobrakes.
    
    	The Soviet Mars program of the early 1960's is a perfect example of
    jumping the gun. At this time, while the Soviets were designing their
    first landers for Mars, most scientist believed that Mars had an
    atmospheric pressure of about 100 millibars (Earth's is about 1000
    millibars). The Soviets excepted this figure and designed a slightly
    egg shaped entry capsule/lander to land on the planet. Such a shape
    would be perfect to slowdown a lander in such an atmosphere.
    	A possible attempt to launch this lander failed in 1962 but it is
    likely another attempt (i.e. Zond 2) succeeded in making it into a Mars
    trajectory at about the same time as the American Mariner 4 in 1964.
    Unfortunately for the Soviets, Zond 2 failed enroute to Mars but even
    if it did make it to Mars, the lander would have impacted the Martian
    surface at hundreds or even thousands of miles per hour.
    	Mariner 4 as well as subsequent Mars missions showed that the
    Martian atmosphere was 20 time thinner than predicted (i.e. only 5
    millibars). The egg shaped entry capsule/lander that the Soviets
    designed and used was useless and was made instantly obsolete. A much
    broader "high hat" shaped aerobrake was needed to adequetly brake an
    incoming Martian lander. This design error likely forced the Soviets to
    abandon their Mars program for the rest of the 1960's until a new
    lander was designed. In addition, they wasted years of effort and
    hundreds of millions of roubles on a worthless lander design.
    
    	The moral of this story: don't send or even design a lander until
    you send a flyby mission to probe the atmosphere otherwise you will
    waste a lot of effort and money.
    
    			Drew
                                                                 

    you know if it was built in space, a telescope with a 1.5 mile
    aperature would not be impossible.  using the space station as
    a base, and not having the earths gravity to slow construction
    and deform the optical device ( lens or parabolic mirror) it
    could be done. not impossible maybe very expensive.
    pete

    	But being realistic, an inexpensive Pluto probe will see completion
    long before a 1.5-mile telescope in space ever will.
    
        Larry
    

    Re:.18
    	I agree that a telescope with an aperture of 1.5 miles is not
    impossible but I can guaranty that none of us will see it in our life
    time. We simply do not have the technology or infrastructure needed for
    such an undertaking. I'm no expert in space structures but I do know a
    few things about optics. For example, a 1.5 mile in diameter segmented
    mirror (the only way we have to build a mirror this large) would need
    about 6 million segment one meter across. At $25,000 per segment (which
    is a bargin basement price for quality optics this large) it would cost
    about $150 billion dollars to make all the needed segments.
    	Of course there is the problem of getting these segments into
    orbit. assuming that the mirror segments were 3 centimeters thick, all
    the glass would weigh about 150,000 tons. It would take 3,600 launches
    of a Shuttle-C at about $150 million per launch to get all the glass up
    there. That comes to about $540 billion. What is even worse is that
    even at a launch every two weeks, it would take almost 140 years to
    launch just the mirror segments alone.
    	In any case, we are up to almost $700 billion just for fabricating
    and launching the optics alone. Throw in the costs of designing, 
    developing, fabricating, and launching the structure to support the 
    optics, all the mechanical, electrical, computer control, and
    propulsion systems as well as the cost to support construction crews in 
    orbit and support bureaucrats on the ground and the cost could easily 
    surpass $4 trillion (and even this is probably underestimating the costs). 
    Spread out over 150 years that would come to $30 billion per year (about 
    the amount of money spent by the US on its civilian AND military space
    programs). 
    	There is no way the US government would make a 150 year commitment 
    (they have a hard time making a ONE year commitment). Assuming that the
    launch capacity could be increased a factor of five over the original
    calculation above (which is already greater than the total launch
    capacity of all the spacefaring nations combined) then the project
    could be completed in 30 years at $150 billion per year (about twice
    the combined space budgets of all the space faring nations).
    
    	Well, I could drone on and on but as can be seen, building such a
    large telescope would be a VERY expensive undertaking and would require
    a significant enhancement in the world's space capabilities. In the
    mean time, a couple of hundred million dollars for a probe to Pluto
    looks like a real bargin!
    
    				Drew
    

    I didn't write .18, but I think .18 was not referring to building tyhe
    1.5 mile mirror on the ground and building it in space, he was talking
    about USING the advantages of space to build a large telescope.  I.E.
    no gravity to inhibit mirror size (of course when you get pretty large
    there are tidal forces!).
    
    All in all, I think building a mirror in space, from spaced bassed
    materials, would be quite a bit less expensive than buildin the pig on
    earth and haluing it up there bit by bit.  We could probably build it
    within one or two years of getting that mass driver on the moon
    operational.  In fact you might just want to build it in lunar orbit,
    lower tidal forces.
    
    Yes, it will probably cost more than a pluto probe, but if you take as
    given a commitment to a lunar base (and really most exploration of
    space is eventually for utilization, if not of the materials
    themselves, at least of the knowledge), a large telescope, built in a
    mostly automated mode, in lunar orbit, with lunar materials (the moon
    is mostly silicon and oxygen, optical mirrors are, I think made of
    SiO2), wouldn't add much at all, INCREMENTAL funding.  
    
    AND it would be vastly more useful.
    
    Tony
                                       

Also not .18's author but:

Nothing says that is has to be a glass mirror. With space as an environment you
could build a reflector from silvered mylar. Using some of the shape memory 
plastic technology you should be able to have a "pop back to shape" structure 
to support it. Again, expensive but doable. (and not 150k tons of materials) 

    [Nuts - beaten to the punch (not all optical mirrors are glass)]
    
    How about silvered mylar spun up such that the edge spin speed is
    something that mylar can handle but which can give the beast some
    natural tension (shouldn't take much).  That, combined with some
    simple, lightweight, 'guiding' structure, it should be able to keep its
    shape at critical points.  To aim it might require a spin-down.
    
    Something tells me that this has already been 'invented'.
    
John

    	The little story I was spining in .20 was to show how terribly
    difficult and expensive it would be to build a 1.5 mile in diameter
    telescope with TODAY'S available technology, resources, and space
    related infrastructure. The point I am trying to make is that it will
    be an expensive and difficult task and that in comparison a Fire & Ice
    like mission to Pluto is an absolute bargin.
    
    Re: .21
    	I completely agree that making the telescope out of material from
    the Moon (or even asteriods) would be MUCH cheaper and better way of
    constructing such a large telescope. The problem at this point in time
    is that we do not have even the beginings of the infrastructure needed
    to mine one ounce of lunar material for any space based construction
    projects. I think it will be several decades before we begin to see
    even small scale mining on the Moon. The large scale mining operations
    needed to build this telescope probably will not be in place for a
    century beyond that. Any way you cut it, no one alive today will see
    that kind of telescope built (but I hope we get to see a flyby of Pluto
    at least).
    
    Re: .22 & .23
    	I agree completely that optics don't need to be made of glass but
    then again we have absolutely no experience handling sheets of mylar
    miles in diameter. It is, however, more likely that we will see a 
    telescope of this type of before we see the one I discribed in .20 .
    	Another type of telescope which is even more exotic would make use
    of powerful lasers. I read about this several years ago and the details
    are fuzzy but basicly a small array of powerful lasers (of about the
    same class as the ones envisioned for SDI) and the appropriate laser
    optics are arranged so that they focus their light in large concentric
    bands. The intensity would be great enough ionize the interplanetary
    gas in these bands. These ionized bands would then act as the rings in
    a Fresnel lens and focus incoming star light. Granted this was nothing
    more than a paper study and a lot of work remains to be done (MUCH more
    than with the mylar lens concept) but it is just an example of
    alternate methods of building large aperture telescopes.
                              
    				Drew
    

Just an aside but if or when they do build something that large they 
probably wouldn't do it in orbit around the Earth but rather in a solar 
orbit (I tend to think that once we get to 1.5 mile wide objects we'll be 
hopping all over the solar system).

If they did put it into Earth orbit can you image how that thing would look 
orbiting the Earth?!  WOW!

Rich

    	The Soviet Union is studying the possibility of launching a large
    solar probe of their own using the Energia booster sometime around the
    turn of the century. Unfortunately, no details are yet available on how
    they plan to accomplish this. A Jupiter flyby is possible but they do
    not have any interplanetary spacecraft that have demonstrated the
    required 4 to 5 year lifetimes to accomplish this mission (the longest
    lived Soviet interplanetary probe lasted about 15 months; Astron which
    was based on the Venera spacecraft lasted about 3 years). The other
    possibility is using brute force; have Energia launch the probe plus a
    large rocket stage or two and use that to reach the Sun directly from
    the Earth.
    
    				Drew
              

    Re. The discussion on building a large aperture telescope in orbit.
    
    Has anyone considered how vulnerable such a structure would be to
    collisions with dust particles and orbital junk? A few years ago
    it was estimated that the probability of a collision between a piece
    of debris and a working satellite was approaching significant
    proportions. An object 1.5 miles in diameter would be almost certain
    to be hit within its operational lifetime.
    
    This was one of the more minor problems with the proposed solar
    power satellites, which would need to have areas measured in square
    kilometres to be useful.
    
    
    Dave Hazel

I seem to remember an article about the use of a holographic lens... that is a 
hologram that performed the same as a physical lens. I don't remember where but 
it may have been in a back issue of NASA Tech Briefs...

Anyone have any information on this technique or care to "shoot holes" in it?

(I couldn't resist)

Jim

    Wow, I just saw a neat article about spaced bases telescopes.  One of
    the ideas mentioned was using the SUN, as a gravity lens.  Of course
    this was a highly speculative article, but it stated that using the sun
    we could detect planets in ANDROMEDA!!!!!!!  That is something like
    2.2 million light years away.  Of course this technology would be able
    to resolve any object in this solar system to a scale in the order of
    magnitude of meters.  
    
    One problem is that you need a collector near the orbit of Uranus, so
    it won't help mapping Pluto too much  ....  
    
    But this is just the kind of thing I meant.  Lets invest in things that
    get us big payback, like a collector a solar lens telescope, rather
    than a fly-by of a relatively uninteresting planet (Pluto).
    
    Tony
         

    Re. -.1
    
    > One problem is that you need a collector near the orbit of Uranus...
    
    ...with consequent distortion of the image due to the gravitational
    effects of the other planets, the interplanetary medium, and the
    Sun's atmosphere.
    
    How much detail did this article go into, or was it another of those
    "Gee whizz, see what we can do with a few impressive numbers?"
    newspaper articles.
    
    My first reaction to this is that it would probably turn out to
    be cheaper to build another HST-like spacecraft with 10 times the
    aperture, than to try to solve the problems with this kind of scheme.
    Remember that the collector is going to have to be looking at the
    Sun, which would be somewhat brighter than any planets in the Andromeda
    galaxy. (I assume that's what you mean by "in Andromeda". Or were
    you referring to the constellation?)
    
    In terms of its gravitational lensing capabilities, the Sun would
    certainly provide some interesting food for hypothetical models
    of telescopes, but it has other properties which reduce its usefulness
    in this respect.
    
    
    Dave Hazel

    	The article is from the June 1990 issue of FINAL FRONTIER magazine,
    which devotes itself to space news and information for the general 
    public.
    
        Regarding Note 565.29, I would like to disagree that Pluto is an
    uninteresting object.  We haven't even been able to study it up close
    yet, so how can such a thing be said about the unknown?  As VOYAGER
    proved many times in its mission, there are plenty of surprises left
    for us in space.
    
    	Larry
    

    > <<< Note 565.30 by 42070::HAZEL "Intelligence > knowledge + memory" >>>
    >                       -< A very bright lens... >-

    >> One problem is that you need a collector near the orbit of Uranus...
    >
    >...with consequent distortion of the image due to the gravitational
    >effects of the other planets, the interplanetary medium, and the
    >Sun's atmosphere.
    
    Well, I think there are work arounds for that, like there is no reason
    to confine our collector to the ecliptic plane.  In fact, it might just
    be more advantagous in terms of the portion of the sky to have a
    "polar" orbit of the sun.
    
    >How much detail did this article go into, or was it another of those
    >"Gee whizz, see what we can do with a few impressive numbers?"
    >newspaper articles.
    
    Not really much detail, it was in a space advocacy magazine.
    
    >My first reaction to this is that it would probably turn out to
    >be cheaper to build another HST-like spacecraft with 10 times the
    >aperture, than to try to solve the problems with this kind of scheme.
    >Remember that the collector is going to have to be looking at the
    >Sun, which would be somewhat brighter than any planets in the Andromeda
    >galaxy. (I assume that's what you mean by "in Andromeda". Or were
    >you referring to the constellation?)
    
    Possibly, it would be cheaper to build a 10X Hubble, but certainly the
    potential for this kind of scheme is FAR in excess of 10X the Hubble.
    
    Yes, I meant the Andromeda Galaxy.  I'm not sure that you could see
    light from the planets in Andromeda, just know that there are planets. 
    You can detect planets through inferential means, wobbling of orbits,
    IR signature, etc.
    
    >In terms of its gravitational lensing capabilities, the Sun would
    >certainly provide some interesting food for hypothetical models
    >of telescopes, but it has other properties which reduce its usefulness
    >in this respect.
    
    Not sure what you mean here ....  If you are talking about the
    brightness of the sun, remember that since we are talking about the
    interplanetary medium (i.e virtually hard vacuum), you can ignore the
    brightness of the sun itself.  It should be relatively trivial to
    occlude the rays from the sun and only examine/analyze those rays that
    are of extrasolar origin.
    
    Tony

    >     <<< Note 565.31 by 26523::KLAES "The Universe, or nothing!" >>>
    >                             -< RE 565.30 >-
    >
    >    Regarding Note 565.29, I would like to disagree that Pluto is an
    >uninteresting object.  We haven't even been able to study it up close
    >yet, so how can such a thing be said about the unknown?  As VOYAGER
    >proved many times in its mission, there are plenty of surprises left
    >for us in space.
    
    I Larry is 100% correct, I chose my words poorly.  I'm sure that Pluto
    will be quite interesting when we get to look at it.  All I meant to
    say was that with the realistically finite resources available for
    planetary missions, space telescopes, etc.  I did not think that the
    highest cost/scientific benefit ratio could be derived from a Pluto
    mission.
    
    We are faced with a form of triage in our space program.  Which
    activities give the X number of $ allocated to planetary science the
    highest payback of scientific information?  In my opinion, more
    detailed study of the moon, which even at this late date is not yet
    100% mapped!!!!!!! (I think it is something like 90% mapped), is of FAR
    higher priority than a trip to Pluto.
    
    Tony

    re.32  It's not just the brightness of the sun itself, but, as an earlier
    reply noted, its atmosphere. If you screen out the disk of the sun
    itself, as happens in a total eclipse, then the corona becomes visible.
    It is not bright compared to the sun itself, but it is more than
    bright enough to obscure any faint object behind it, and it extends
    for a considerable distance around the sun (some millions of miles,
    I believe). In addition to its own radiation, it is probably far
    more turbulent than earths atmosphere, and you would be looking
    through it at a shallow angle, rather as when an object is close to
    the horizon here; the distortion is then a lot greater than when 
    looking straight up from the surface. 
    
      In addition, any detector sensitive enough to do useful work with
    a sun-sized gravity lens, would probably be far too sensitive to
    be pointed in that direction. The HST cannot be pointed anywhere
    near the sun; it would destroy its instruments. 
                     
    Ken

As one of the local ads on the radio says...

They'll have to launch/run the mission at night!


;^)

    >   <<< Note 565.34 by 42110::RICKETTS "Have you tried kicking it?" >>>
    >          -< Now if the sun was dark, it might just work... >-
    >
    >re.32  It's not just the brightness of the sun itself, but, as an earlier
    >reply noted, its atmosphere. 

    I don't buy it.  The sun's atmosphere is VERY different from our own. 
    It is mostly hydrogen and helium, little dust or other gasses.

    So what you are telling me is that you cannot use two frequencies of
    light with a solar gravitational lens telescope, those frequencies
    where hydrogen and helium absorb light.  In most other frequencies you
    should get relatively good unimpeded transmission.  Fortunately there
    are an infinite number of frequencies of light and most of them are
    interesting to astronomy.

    Tony

  This experiment struck me as odd as well, for the atmospheric reason and
one other.

>    I don't buy it.  The sun's atmosphere is VERY different from our own. 
>    It is mostly hydrogen and helium, little dust or other gasses.

  But of varying density.  You're going to have refraction problems.

  Besides, imagine trying to focus this thing - it's not like you can just
orbit casually.  You've got to hang in a steady position.  And you'd be
focusing on a moving target (a planet in orbit).  Doesn't sound too practical.
Interesting thought, though.

John

    With respect to the atmosphere of the sun consisting mainly of Hydrogen
    and Helium, wouldn't the diffraction caused by thermal turbulence give
    rise to problems ?
    
    Del.

  One way to answer these questions might be to run a test. Perhaps one of the
Voyager cameras could be pointed back toward the sun to collect data on the
lense effect. They should be far enough away to avoid damage. If not, then a
small collector of some sort could be launch toward Jupiter and be given a
boost out to the outer solar system to collect data in a "fly by" of any
potential focus point.

  It would take a lot of energy (i.e.) a huge launcher, to send something
up to a stable point billions of miles from the sun. It's one thing to
get a gravaty assist from Jupiter to get it out there, it's another thing
to put it into a circular orbit at some given point that far out, especially
if the point does not coincide with the orbit of one of the other large
planets.

  Trying to circularize in a polar orbit out near the outer planets would
be even worse.

  If a test with a fly by type of space craft showed a good lense effect,
then it would be worth the effort to put something out there. It would
also tell us what problems would have to be solved to make the thing
usefull

  George

    What sort of resolution will HUBBLE have when looking at Pluto ?
    
    Will it save the need of a probe ?
    
    
    Chris

    Re:.40
    	HST will be able to resolve features as small as about 600 miles at
    Pluto's present distance. That is more than enough to clearly seperate
    Pluto and Charon as seperate objects and just barely enough to to
    resolve them as disks. This is roughly equivalent to a Voyager-like
    imaging system returning images from a range of about 6 million miles.
    
    Re: Using the Sun as a lens
    	I haven't read the article in question but I do know about optics.
    If the detectors for a telescope using the Sun as a lens had to be as
    far from the Sun as Uranus, there is no way that such a telescope could
    image anything in the solar system. They are just too close for a
    gravitational lens to focus an image. Besides, if you can travel as far
    as the distance of Uranus and maneuver around at that distance (which
    would be necessary for a useful telescope), you can go to the planets
    directly anyway.
    	As far as actually detecting planets in nearby galaxies using such
    a telescope, it is absolutely impossible. While the hot turbulent
    outer atmosphere of the Sun would not significantly degrade the image
    (because it is SOOOOOO rarified that refraction would amount to an
    insignificant fraction of a microarc second), the brightness  of the
    atmosphere would totally drown out any signal. First, the detector
    would need a dynamic range of over 150 dB (compared to a dynamic range
    of 20 to 35 dB for today's imaging detectors). Even if we had such an
    imaging detector, the faint signal from a potential planet would be
    lost in the Poisson photon noise of the detected signal. Even if you
    could detect each and every photon reaching the detector (which we can
    do today under certain conditions) it would require an exposure time
    orders of magnitude greater than the age of the universe to even make a
    marginal detection.
    	All in all an interesting concept but it is completely impossible
    for it to deliver as advertised.
    
    					Drew
    
     

One issue that was brought up over and over was a stable position. This isn't 
needed due to the capabilities of "smear" processing whereby a smeared image 
can be reconstructed. The close encounter pictures from voyager are good 
examples.

>       <<< Note 565.41 by 15372::LEPAGE "Serving the servants of man" >>>
>                          -< Can NOT Work...Period! >-
>
>    	As far as actually detecting planets in nearby galaxies using such
>    a telescope, it is absolutely impossible.  
    
    Drew,
    
    I only read the article once in the bookstore.  But what I was trying
    to say, alebit not to effectively, was that the device could confirm
    planets in other galaxies.  Now I wasn't 100% sure how the article
    claimed it could be done.  One possibility that I have thought of was
    that it might be possible to 'confirm' planets in much the same way
    that IRAS 'confirmed' planets around several dozen stars, that is by
    infrared inference and not necessarily by direct observation.  
    
    In any case, I think I read your note to confirm the possibility of
    solar gravitational lens telescope, but that you believe that observing
    extra galactic planets directly would be impossible.  
    
    Tony

From: baalke@mars.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Pluto article
Date: 8 Jan 91 00:04:00 GMT
Sender: news@jato.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, Pasadena, CA.
 
    Washington Times -- 1/7/91
    "Weird Wonders Await Us if Pluto Lovers Convince NASA to Visit Planet 9 
    From Outer Space" 
    By A. R. Hogan
 
"To the best of our knowledge, no people live on Pluto.  But at least
a few "Pluto people" live right here on Earth.  And they want to see
us get closer to the far planet." 
 
The Times reports that one of these "Pluto people" is New Mexico State
University astronomer Clyde Tombaugh who discovered the long-sought
missing planet 60 years ago while working at the Lowell Observatory in
Flagstaff. 
 
The Times reports that in the late 1960s and early 1970s NASA had
mapped out plans to take advantage of a once-in-179-year alignment
which would let scientists use planetary flybys to send a Mariner
spacecraft out as far as Pluto.  However, the Times reports that in
the post-Apollo budget slashing which took place, the only mission to
the outer planets was the two-spacecraft Voyager mission to Jupiter
and Saturn. 
 
The story says that undaunted astronomers continued to explore the 9th
planet from ground-based telescopes and in 1976 astronomers from Kitt
Peak detected a methane-ice surface on Pluto and later in 1978 Naval
Observatory astronomers discovered Pluto to be, in actuality, Pluto
and its near-twin-sized moon -- Charon. 
 
The paper says that, for the past five years, the dance of the planet
and its moon have presented astronomers with a series of eclipses
which have revealed more about both objects' composition and size. 
 
The story says that very recently astronomers at the Space Telescope
Science Institute have applied image analysis to the photographs of
the pair and deduced that Pluto is 1,450 miles in diameter, has a
surface temperature averaging minus 390 and has white polar caps which
are three to four times as bright as its slightly reddish equatorial
region. 
 
The story says that following the 1993 Hubble repair mission, that the
space telescope should provide images which will enable a better
analysis of Charon, as well. 
 
The story continues with information provided by Tombaugh as to why a
visit to Pluto would be even more beneficial and cites work performed
by Goddard Space Flight Center trajectory designer Robert Farquhar
which indicates a mission to Pluto could be performed with a Delta-
class vehicle and a lot of gravitational assist from the other planets. 
 
The story concludes by noting that the world's 40 to 50 serious Pluto
people are planning for a 1992 Pluto conference to be held in
Flagstaff and that there is a growing groundswell for a Pluto mission.

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

Article        32942
From: tholen@galileo.ifa.hawaii.edu (Dave Tholen)
Newsgroups: sci.space
Subject: Re: Pluto flyby
Date: 9 Jul 91 01:50:08 GMT
Sender: news@uhccux.uhcc.Hawaii.Edu
Organization: Institute For Astronomy, Hawaii
  
Nils C. Egberts writes:
 
> Who knows more about the plans (or ideas) to send a space probe towards
> Pluto/Charon. 
 
A recent meeting of the SSES (Solar System Exploration Subcommittee) 
assigned high priority to a Pluto flyby mission.  A NASA working group
is currently preparing a more detailed mission proposal for consideration
by the SSAAC (Space Science and Applications Advisory Council).  If this
committee also assigns high priority to this mission, more detailed studies
will be initiated, with a new start possible in FY96, give or take a year.
 
> I have heard that there is a plan to send two probes as well, just for
> economical reasons.
 
The Pluto flyby mission is being teamed with a Neptune orbiter mission, much
in the same way that CRAF and Cassini are being teamed.  The commonality of
the two spacecraft designs makes it more economical than using two spacecraft
of different design.  The Pluto and Neptune missions would be the next pair
of missions to use the Mariner Mark II concept, with the heritage from CRAF
and Cassini helping to keep down costs.
 
The working group is considering two options to overcome the problem of a
single spacecraft flying past Pluto in a time short compared to the rotation
period of the planet (which would otherwise prevent global, high resolution
imaging).  One involves using a daughter spacecraft, separated from the
mother some 100 days before encounter and given enough delta-V to produce
a 3.2 day difference in encounter dates; the other involves the development
of a super narrow angle camera that would permit high resolution imaging
3.2 days prior to close approach.

        "Sometimes, the one thing that you're looking for, it's the last
    thing on your mind." - Robbie Nevil 

Article: 38598
From: blloyd@axion.bt.co.uk (Brian Lloyd)
Newsgroups: sci.space
Subject: Re: High speed extrasolar probes to Pluto
Date: 13 Dec 91 14:42:57 GMT
Sender: news@axion.bt.co.uk
Organization: British Telecom Labs
 
From article <1991Dec12.115117.23321@axion.bt.co.uk>, by
blloyd@axion.bt.co.uk (Brian Lloyd): 

> There's an article about a possible Neptune orbiter / Pluto flyby mission in
> this month's Spaceflight. According to that, the Pluto flyby part would have
> to go fairly soon (~2001? - I haven't got the article with me) otherwise the
> atmosphere of Pluto will have condensed out before the probe gets there. If
> anybody's interested I could bring in the article and summarise it.

I was right - it is 2001. The following are some of the key points :
 
* Both probes would be Mariner Mark II spacecraft.
* Both launched by Titan/Centaur.
* Launch for Pluto in 2001, with gravity assists from Earth and Jupiter.
* Launch for Neptune 8 months later, in 2002, with gravity assists from
  Venus (twice), Earth and Jupiter.
* Observation of Pluto one year before and after closest approach.
* 100 days before closest approach to Pluto, a daughter spacecraft with
  imaging instruments only will be released to arrive at Pluto 3.2 days
  (half a Pluto revolution) after the main craft, so that both hemispheres
  of Pluto and Charon can be imaged.
* Pluto probe will continue out at a speed of about 3 AU per year, and should
  reach 75 to 110 AU before its useful life ends.
* Neptune spacecraft will release a probe 6 to 8 days before closest
  approach. This will enter the atmosphere of Neptune.
* Neptune orbitor's mission to last 4 years, with 25 to 45 gravity assists
  from Triton.
 
One benefit of using the 2001 to 2003 launch window instead of the next
Jupiter-assist launch window (2011) is that it would be more feasible to use
the Mariner Mark II, since after CRAF/Cassini it would be difficult to
replicate as parts became unavilable.
 
Science return from Cassini is likely to end about 2008 - 2010. There would
therefore only be a `short' gap before data starts coming from the
Pluto-bound craft (2014 - 2016, ie a year before and after closest
approach), followed by data from the Neptune craft from 2021 - 2025.
 
Brian

Article: 38603
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space
Subject: Re: High speed extrasolar probes to Pluto
Date: 14 Dec 91 02:45:02 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
 
In article <1991Dec13.144257.8415@axion.bt.co.uk>,
blloyd@axion.bt.co.uk (Brian Lloyd) writes... 

>From article <1991Dec12.115117.23321@axion.bt.co.uk>, by
>blloyd@axion.bt.co.uk (Brian Lloyd): 
>> There's an article about a possible Neptune orbiter / Pluto flyby mission in
>> this month's Spaceflight. 
>
[summary of article deleted]
 
Nice summary.  One thing that you left out was why a Neptune mission
is being considered, but not a Uranus mission.  Even though Uranus is
closer, Neptune is a more interesting place to study.  Neptune had a
Great Dark Spot and other clouds that can be easily studied from an
orbiter.  Uranus is rather bland. Uranus does not have any large moons
which could be used by an orbiter for gravity assists.  Neptune has
one large moon, Triton, which also has active geysers. 

     ___    _____     ___
    /_ /|  /____/ \  /_ /|     Ron Baalke         | baalke@kelvin.jpl.nasa.gov
    | | | |  __ \ /| | | |     Jet Propulsion Lab |
 ___| | | | |__) |/  | | |__   M/S 525-3684 Telos | There's no limit to what
/___| | | |  ___/    | |/__ /| Pasadena, CA 91109 | can be done if it doesn't
|_____|/  |_|/       |_____|/                     | matter who gets the credit.

Article: 38607
From: henry@zoo.toronto.edu (Henry Spencer)
Newsgroups: sci.space
Subject: Re: High speed extrasolar probes to Pluto
Date: 13 Dec 91 21:44:48 GMT
Organization: U of Toronto Zoology
 
In article <1991Dec13.144257.8415@axion.bt.co.uk>
blloyd@zaphod.axion.bt.co.uk writes: 

>* Launch for Pluto in 2001...
>* Launch for Neptune 8 months later, in 2002...
>... gap before data starts coming from the
>Pluto-bound craft (2014 - 2016, ie a year before and after closest
>approach), followed by data from the Neptune craft from 2021 - 2025.
 
Note that we've got some seriously optimistic people here:  the Neptune
mission spends nearly *twenty years* in space before reaching Neptune.
Even the Pluto part has a flight time of nearly fifteen.  And no backup
spacecraft either.
 
A pessimist would say that the missions would reach Neptune and Pluto
sooner if we spent the money between now and 2001 on propulsion engineering,
instead of on building yet another set of probes for propulsion-critical
missions using thirty-year-old chemical rockets.

    Henry Spencer @ U of Toronto Zoology
    henry@zoo.toronto.edu  utzoo!henry

Article: 48207
Newsgroups: sci.space
From: irwin@iago.caltech.edu (Horowitz, Irwin Kenneth)
Subject: Re: Pluto Direct/ options
Sender: news@cco.caltech.edu
Organization: California Institute of Technology
Date: Tue, 8 Sep 1992 04:37:00 GMT
 
In article <1992Sep7.173253.1837@access.digex.com>,
prb@access.digex.com (Pat) writes... 

>I saw parts of the pluto direct flyby talk by staehle from JPL.
>they are talking of sending a 1-200 kg orbiter to pluto.
> 
>Did they consider using energia?  most of the charts I remember
>were using titan or delta class launchers?
> 
>I was thinking an energia would allow a bigger bird or possibility of
>more thrust to slow down the encounter.
> 
>Does anyone know if that's an idea, or do they want to hold costs down
>to $150 million?

I was also at Staehle's talk at the WSC and since I have some
background on this mission, I will attempt to describe it. 
 
The plan is to send a pair of spacecraft to Pluto on a direct
trajectory. The mass of each craft is currently 164kg.  They are
talking about launch on either a Atlas or a Proton (the Atlas would
allow a slightly higher payload mass).  The current launch date is
1998, with an 8 year flight time to Pluto.  Each craft will be able to
carry out 4 primary science experiments: Optical imaging using a CCD
camera, UV spectroscopy, an IR payload and radio science using the
main antenna.  The mass allocation for the three instruments is only a
few kgs.  Power will be provided by an RTG. 
 
This mission is an example of the new "cheaper, faster, better"
attitude that Goldin is trying to bring to NASA.  The budget is only
$400M for the entire mission, and they are real serious about sticking
to that figure.  Getting the craft off the ground in six years is much
faster than other big projects that NASA has undertaken in recent
years (JPL is learning a hard lesson from CRAF/Cassini).  As for
better, well that will have to wait until they get out to Pluto to
determine :-).  The primary drivers in the past were performance,
schedule, cost.  For this mission, these have been reversed, so that
cost is the primary consideration, and they are going to overlook a
lot of potentially interesting science in an attempt to avoid the
pitfalls of many other projects, that just grew too big b/c everyone
wanted a piece of the pie.  In addition, Staehle is committed to
bringing a large number of students into the project, and primarily
those students will come from local SEDS chapters here in LA.
(SEDS==Students for the Exploration and Development of Space). 
Indeed, if you had the chance to see the mockup of the flyby craft in
the exhibition hall (in the main NASA area in front), that was built
by one of the members of Caltech SEDS as his summer project. 

-------------------------------------------------------------------------------
Irwin Horowitz                        |
Astronomy Department                  |"Whoever heard of a female astronomer?"
California Institute of Technology    |--Charlene Sinclair, "Dinosaurs"
irwin@iago.caltech.edu                |
ih@deimos.caltech.edu                 |
-------------------------------------------------------------------------------

Article: 48208
Newsgroups: sci.space
From: jbh55289@uxa.cso.uiuc.edu (Josh 'K' Hopkins)
Subject: Re: Pluto Direct/ options
Sender: usenet@news.cso.uiuc.edu (Net Noise owner)
Organization: University of Illinois at Urbana
Date: Tue, 8 Sep 1992 04:51:02 GMT
 
prb@access.digex.com (Pat) writes:
 
>I saw parts of the pluto direct flyby talk by staehle from JPL.
>they are talking of sending a 1-200 kg orbiter to pluto.
 
Actually, they'd like to send two so that they can image both sides of
the planet. 
 
>Did they consider using energia?  most of the charts I remember
>were using titan or delta class launchers?
 
The two options are Titan IV and Proton (which is a Soviet rocket with
a smaller fan club than Energia).  They would prefer to use a Proton
because of pricing, but they're unsure of the performance of Proton
upper stages. 
 
>I was thinking an energia would allow a bigger bird or possibility of
>more thrust to slow down the encounter.  
 
The problem is that a bigger probe is much more expensive, and you
can't really slow down the encounter much without extending the trip
time greatly. 
-- 
Josh Hopkins           "If you are sitting in an exit row and you cannot read
                       this card or cannot see well enough to follow these
		       instructions, please tell a crew member."
j-hopkins@uiuc.edu                       -United Airlines safety instructions

Article: 48215
Newsgroups: sci.space
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Subject: Re: Pluto Direct/ options
Sender: news@elroy.jpl.nasa.gov (Usenet)
Organization: Jet Propulsion Laboratory
Date: Tue, 8 Sep 1992 23:21:11 GMT
 
In article <1992Sep7.173253.1837@access.digex.com>,
prb@access.digex.com (Pat) writes... 

>I saw parts of the pluto direct flyby talk by staehle from JPL.
>they are talking of sending a 1-200 kg orbiter to pluto.
> 
>Did they consider using energia?  most of the charts I remember
>were using titan or delta class launchers?
 
A Pluto mission has always been a high priority since it is the only
planet we have not sent a probe to.  Also, since 1979, Pluto is closer
to the Sun than Neptune and will not cross back over until February
10, 1999, and this is the closest Pluto will be for another 248 years.
The proposed plan is to send two small spacecraft on a direct
trajectory to Pluto for a flyby encounter.  There will be no gravity
assists, not even from Jupiter.  The cruise time would be from 7 to 8
years with a Titan-4/Centaur launch, or 10 to 12 years with a backup
Proton/D1E launch vehicle.   Each spacecraft would weigh 330 pounds
and carry a science payload of 15 pounds consisting of an imaging
system (expected resolution at 1km), an infrared spectrometer and an
ultraviolet spectrometer.  The atmosphere of Pluto would also be
studied with radio occultation. 

The reason for two spacecraft is that Pluto/Charon have a 6.4 day
rotation rate, and a single spacecraft can only study one side from
close range with a flyby encounter.  The launches of the two spacecraft 
will be staggered by 3.2 days to allow observations of both sides of 
Pluto and Charon. The total cost of the mission would be no more than 
400 million dollars and the launch dates would be in 1998 or 1999. 

     ___    _____     ___
    /_ /|  /____/ \  /_ /|     Ron Baalke         | baalke@kelvin.jpl.nasa.gov
    | | | |  __ \ /| | | |     Jet Propulsion Lab |
 ___| | | | |__) |/  | | |__   M/S 525-3684 Telos | Anything is impossible if
/___| | | |  ___/    | |/__ /| Pasadena, CA 91109 | you don't attempt it.
|_____|/  |_|/       |_____|/                     | 
 

                         PLUTO FAST FLYBY FACT SHEET
                               March 1993

Solar System Exploration Division

* MISSION SUMMARY *

Pluto, the smallest planet in our solar system, has remained enigmatic since
its discovery by astronomer Clyde Tombaugh in 1930.  Pluto is the only planet
not yet viewed close-up by spacecraft, and given its great distance and tiny
size, study of the planet continues to challenge and extend the skills of
planetary astronomers.  Most of what we know about Pluto we have learned
since the late 1970s.  Such basic characteristics as the planet's radius and
mass were virtually unknown before the discovery of Pluto's moon Charon in
1978.  Since then, observations and inferences about Pluto-Charon, now
considered a "double-planet" system, have progressed steadily to a point where
many of the key questions about the system must await the close-up observation
of a space flight mission.

For example, there is a strong variation in brightness, or albedo, as Pluto
rotates, but we do not know if what we are seeing is a system of varied
terrains, or areas of different composition, or both.  We need a much closer
look to understand these features and the chemical, geological and perhaps
orbital history they represent.  We know there is a dynamic, largely nitrogen
and methane atmosphere around Pluto that waxes and wanes with the planet's
elliptical orbit around the sun, but we need to understand how the atmosphere
arises, persists, is again deposited on the surface, and how some of it escapes
into space. Telescopic studies indicate that Pluto and Charon are very
different bodies, Pluto being more rocky, Charon more icy.  How and when the
two bodies in a double-planet system could have evolved so differently is a
question that awaits data from close-up observation.

More fundamentally, beyond our basic interest in Pluto and Charon, is the
likelihood that these bodies hold important keys to our understanding of the
giant planets and comets and their role in the formation of the solar system.
From the Voyager missions to the outer planets and their moons, we have a basic
inventory of the characteristics of the icy and rocky bodies of the outer solar
system. We have learned much about such planet-like bodies as the moons Triton
and Titan, and are beginning to understand Pluto as a third member of this
triad of small outer "planets." Data about Pluto and Charon, gathered using
ground-based and Earth-orbiting observatories like the Hubble Space Telescope,
continually improve our understanding of these bodies and have helped define
the important questions about Pluto-Charon.  To address these questions, NASA
is now studying a robotic reconnaissance mission to Pluto-Charon called PLUTO
FAST FLYBY.

Pluto Fast Flyby will be unique in its approach.  In order to minimize cost,
while containing the risks associated with lower cost, Pluto Fast Flyby is
being conceived as a pair of very small spacecraft, using, where possible,
lightweight advanced-technology hardware components.  The baseline Pluto Fast
Flyby mission, based on a 1996 new start authorization, calls for launch of
the two ~110-150 kg spacecraft in 1999-2000 toward encounters with Pluto and
Charon around 2006-8.  Pluto began receding from the Sun in 1989, and its
thin atmosphere is condensing out into surface frost as it cools. Therefore,
minimizing flight time and launching at an early opportunity is important for
the mission's atmospheric and surface science objectives (see below).  There is
a direct relationship between spacecraft weight and flight time, so spacecraft
design tradeoff analyses are particularly critical for this mission.

* PLUTO FAST FLYBY SCIENCE OBJECTIVES *

o   Characterize Pluto's and Charon's global geology and geomorphology.

o   Map the surface composition of both sides of each body.

o   Characterize Pluto's neutral atmosphere, measuring its composition, thermal
    structure, and aerosol content.

* CANDIDATE EXPERIMENTS *

o   Visible Imaging System: a charge-coupled device (CCD) imaging camera to map
    surface features and geomorphology of Pluto and Charon, and to search for
    small satellites.

o   Infrared Mapping Spectrometer (perhaps sharing foreoptics with the CCD
    camera) to study the surface composition of Pluto and Charon.

o   Ultraviolet Spectrometer to measure atmospheric composition.

o   Radio Science Uplink Occultation Experiment to profile temperature and
    pressure of the atmosphere from the surface through the ionosphere.

* MISSION CHARACTERISTICS *

TRAJECTORY:              Two spacecraft, on direct trajectories (i.e.,
                         no gravity-assists)
LAUNCH VEHICLES:         Titan IV/Centaur or Proton; both would entail
                         kick stages
LAUNCH DATES:            1999-2000, assuming a 1996 new start
CRUISE:                  6.5-8.5 years, depending on mass
CRUISE SCIENCE:          None planned, but asteroid flyby, other
                         imaging, H/He detection, and radio science
                         are possible
ARRIVAL AT PLUTO-CHARON: 2006-2008, depending on mass and assuming a
                         1996 new start
FLYBYS:                  PFF-1 @ 10,000 km; PFF-2 TBD based on PFF-1
                         results; both flybys @12-18 km/sec
DATA RETURN:             Onboard storage capability of at least 400Mb
                         per spacecraft; science data downlink at 25-
                         40 bps to 34-meter ground stations


* BASELINE SPACECRAFT CHARACTERISTICS *
TYPE:                    Highly miniaturized descendant of the present
                         class of outer solar system platforms:
                         aluminum hexagonal bus, no deployables
MASS:                    Less than 150 kg; goal is 110-120 kg
                         (7 kg total instrument allocation)
Power:                   RTG source providing 65 watts at Pluto
Communication:           X-Band transponder; 1.47 meter high-gain antenna
Propulsion:              Pressure-fed hydrazine monopropellant design
                         delivering 350 m/s delta-V
Attitude Control:        Widefield star sensor and three solid-state
                         rate sensors
Pointing Knowledge:      Will exceed 1.5 mrad; stability of 10 urad
                         over 1 sec
Slewing Ability:         90 in 3 minutes via cold nitrogen gas
                         thrusters

                         THE PLUTO FAST FLYBY CHALLENGE:
                        A BIG MISSION FOR SMALL SPACECRAFT

Recent interplanetary spacecraft like Galileo and the upcoming Cassini have
been designed relatively large and heavy in order to bring a maximum
exploration payload (including probes) through gravity assists and the intense
radiation of Jupiter.  A large mission of this type to Pluto had been under
consideration since the Voyager 2 encounter with the frigid Neptunian moon
Triton in 1989.  The encounter revealed to a surprised science community that
Triton had polar ice caps, evidence of seasonal changes, active volcanism, and
an atmosphere.  The implications for Pluto and Charon were recognized
immediately, and spurred plans for a Cassini-class mission.  But recent
emphasis at NASA on smaller, cheaper, and faster missions pointed toward the
possibility of a much smaller mission to Pluto-Charon.  The key for such a
mission is to deliver a scientifically useful payload to the distant system at
minimum cost, and to do so before Pluto's atmosphere collapses (in about 2020).

The Pluto Fast Flyby baseline emerged from careful consideration of a complex
web of tradeoff analyses regarding trajectory, weight, risk, and durability,
within an envelope of low-cost and scientific goals. The overall scientific
goals for a mission to Pluto and Charon were articulated and prioritized by
NASA's Outer Planet Science Working Group (OPSWG) and endorsed by the Solar
System Exploration Subcommittee of the NASA Advisory Council.  The goals
adopted for Pluto Fast Flyby are the three first-priority goals of the OPSWG:
study of the geology and morphology, mapping of the surface composition, and
neutral atmosphere.
     ___    _____     ___
    /_ /|  /____/ \  /_ /|     Ron Baalke         | baalke@kelvin.jpl.nasa.gov
    | | | |  __ \ /| | | |     Jet Propulsion Lab | 
 ___| | | | |__) |/  | | |__   M/S 525-3684 Telos | The hardest thing to learn
/___| | | |  ___/    | |/__ /| Pasadena, CA 91109 | in life is which bridge to
|_____|/  |_|/       |_____|/                     | cross and which to burn.

re .48
    
>DATA RETURN:             Onboard storage capability of at least 400Mb
>                         per spacecraft; science data downlink at 25-
>                         40 bps to 34-meter ground stations
    
    At 40 *bits* per second and 400 Mbytes, it will take 971 days (ignoring
    overheads) to return the data. Still I guess that after the fast flyby
    it won't have much better things to do than dribble the data back.

But you can do better than that with compression and you can have 
onboard algorithms that look for interesting images before 
transmitting.

re .50
    
>But you can do better than that with compression
    
    You are of course assuming that the data is not stored on the tape
    compressed (or at least not compressed as effectively as it will be on
    transmission). I don't know off hand whether this is the case.

From alt.sci.planetary (jb):
----------------------------

To clear up the arguments about flight times to Pluto here are some
actual numbers, computed from a program which solves the equations of 
motion using a simple second order ODE solver. 

The problem I solved is the flight from R = 1 AU to R = 30 AU, with
different initial velocities, all applied in the same direction as the
earth's motion. This way you get the most oomph for your $$.

Note that Pluto's velocity about the sun is about 6 km/s at 30 AU. You
cannot necessarily subtract this from the arrival velocity as the two
velocity vectors are in different directions.

Initial Velocity (km/s)    Travel Time (yr)   Arrival velocity (km/s)
(relative to earth)                          ( relative to sun)

  11.7                        30.5              1.4
  12.0                        16.7              4.8
  12.3                        13.7              6.9
  12.6                        12.1              8.7
  13.2                        10.1             11.1
  13.8                         8.9             13.5
  14.4                         8.0             15.3
  15.0                         7.4             16.8
  15.6                         6.9             18.3

The first line is the minimum energy trajectory. You arrive nice and slow, but
many of us will be too old to care or dead on arrival. This situation gets
worse very rapidly as Pluto gets further from the sun, it takes 46 yrs to
reach 40 AU for example. The last line is presumably close to what NASA is
looking at.

The bottom line is that there are enormous gains to be made by going as fast
as you can at the start. Arrival velocity can be kept down, but ony at the
expense of waiting forever. Personally I'd rather have a quick flyby ( 2 in 
fact) early next century than have a slow one and wait until 2040!

Warwick Kissling.

[My apologies Larry, I forgot about this...]

  the file is in pragma::public:[nasa]radpluto.gif

(the [.marsh] directory is my marshalling area -- a holding tank for incoming
 stuff that I haven't placed in the archives)...


- dave

From:	US1RMC::"R4650001@nickel.laurentian.ca" "Andrew Yee, Science North" 
        29-SEP-1993 22:08:17.53
To:	sci-space-news@ames.arc.nasa.gov
CC:	
Subj:	Pluto and Charon: Planets on the edge

From: "Andrew Yee, Science North" <R4650001@nickel.laurentian.ca>
Subject: Pluto and Charon: Planets on the edge
[From the August 1993 issue (No. 68) of LUNAR AND PLANETARY INFORMATION 
BULLETIN.]

PLUTO AND CHARON: PLANETS ON THE EDGE
By Paul Schenk and Renu Malhotra
Staff Scientists, Lunar and Planetary Institute, Houston, Tx.

Although poorly understood, the Pluto-Charon system is certainly not
boring.  As the largest solid-body object beyond the orbit of Saturn,
Pluto may be the last survivor of a family of outer solar system
planetesimals or possibly planetary embryos.  The recent discovery of
a thin atmosphere and the identification of highly volatile gases
frozen on the surface, as well as complex albedo patterns, suggest a
complex geologic history for this system.  Furthermore, Pluto's highly
elongated, Neptune-crossing orbit and the existence of its large
satellite, Charon, imply a rich dynamical history as well.  Its
composition and dynamical history are key tracers of the evolution of
the outermost solar nebula. 

On July 6-9 this year, planetary astronomers and geologists gathered
in Flagstaff at the Pluto and Charon meeting to discuss the latest
data and theories as well as plans for a proposed mission to this
fascinating binary planet system.  The proposed "fast flyby" mission
late this decade met with universal approval.  In contrast, there was
considerable disagreement about even relatively simple issues such as
Pluto's radius and Charon's density, underscoring the need for a
spacecraft mission to characterize this system. 

Estimates of Pluto's radius based on analyses of the mutual eclipse
events with Charon during 1985-1990 differ from stellar occultation
results: the latter imply a slightly larger radius, hence a lower
density and higher ice-to-rock ratio.  These seemingly small
difference lead to profoundly different inferences about the internal
structure of the planet. 

For Charon, Hubble Space Telescope astrometric measurements indicate a
density of 1.3 g/cc, while Earth-based speckle astrometry yields a
density closer to 2 g/cc.  Again, these differences have important
implications for the origin of this binary system.  A low density
Charon would support a large-impact origin, similar to that currently
favored for the Earth-Moon binary. 

Disagreement also emerged over the surface temperature of Pluto, which
controls the mobility of volatile frosts.  The Infrared Astronomical
Satellite (IRAS) observed Pluto in the infrared, implying a surface
temperature in the mid-50 K range, whereas millimeter-wavelength
observations and the albedo imply temperatures in the mid-30 K's.  The
Pluto-Charon eclipse events have been used to reconstruct Pluto's
surface albedo on a scale of about 100 km.  Differing inversion
techniques produce albedo maps that differ slightly in detail but
which agree in the existence of a bright polar cap and a dark spot at
mid-northern latitudes.  It appears that despite Pluto's large
distance from the Sun and the low solar insolation, it may have a
surprisingly active "climate". 

The dynamical history of the Pluto-Charon system is potentially a
tracer for the evolution of planetesimals and embryonic planets that
populated the outer solar system 4.5 billion years ago.  Although
Pluto's orbit overlaps Neptune's, a complicated set of nested
resonances protects these planets from close encounters.  The
strongest is the 3:2 mean motion resonance with Neptune (Pluto's
orbital period is exactly one-and-a-half-times Neptune's period),
which ensures that conjunctions of these planets occur away from
Pluto's perihelion when Pluto is closer to the Sun than Neptune. Yet
another resonance condition ensures that at perihelion Pluto is always
far above the plane of Neptune's orbit, further increasing the
distance of closest approach. 

Billion year integrations of the planetary orbits indicate that
Pluto's orbit is chaotic, yet stable -- an apparent contradiction.  It
is unlikely that Pluto- Charon formed in this strange orbit.  An old
suggestion that Pluto may be an escaped satellite of Neptune has
become untenable in the face of a variety of dynamical arguments.
Theories that were put forward at the meeting argue for formation in a
more typical near-circular planar orbit and subsequent capture into
the 3:2 resonance early in solar system history. The dynamics of Pluto
may have a great deal to tell us about the early orbital evolution of
the entire outer solar system, including the giant planets. 

It has been suggested that Pluto may be a "twin" of Neptune's large
retrograde satellite, Triton, because of their similarity in size,
bulk density and surface composition.  Nitrogen, carbon monoxide, and
methane, common terrestrial atmospheric constituents (at least in the
Houston area), are frozen on the surfaces of both bodies.  CO2 is also
frozen on the surface of Triton, but, so far, water frost has been
identified only on Charon.  Triton and Pluto both possess thin
atmospheres of nitrogen and methane. 

Pluto is not another Triton, however.  It may be somewhat less dense
than Triton; it is significantly darker, and Charon is darker still. 
Moreover, Pluto has probably not experienced the catastrophic thermal
history of Triton associated with its capture by Neptune. 

So, it appears that we have a reasonable first-order assessment of the
bulk properties of the Pluto-Charon system, but there is considerable
uncertainty in its bulk composition and its geologic and dynamical
history. Was Pluto ever geologically active?  How does the geology
reflect the internal compositon?  What does this system tell us about
the outer solar nebula and how planets form and evolve in that cold,
distant environment? 

The mission to Pluto, currently in the preliminary planning stage,
aims to answer some of these questions and has clearly inspired much
new thinking about the distant system.  The difficulties in reaching
this target 4 billion kilometers from Earth place serious constraints
on the mission (such as a long, seven-year flight time), but new
technology and very lightweight instruments under development offset
some of these problems.  This mission should provide a detailed look
at the geology and composition of the surfaces of Pluto and Charon,
and will complete the reconnaissance of the planets.  At least one
prediction is relatively secure: we are due for some surprises at Pluto. 

			*		*		*

A comparison of Pluto and its known moon shows many similarities and
some key differences. 

PARAMETERS			PLUTO		CHARON

Distance from the Sun,
astronomical units		39.44 (mean)	Same
				29.64 (min.)	Same
				49.24 (max.)	Same

Period of solar orbit,
Earth years			247.7		Same

Period of rotation,
Earth days			6.3872		Same

Inclination of axis,
degrees				122		Same

Inclination of solar orbit to 
ecliptic, degrees		17.15		Same

Distance from Pluto,
kilometers			-----		19,400 (appx.)

Equatorial diameter,
kilometers			2,400 (appx.)	1,200 (appx.)

Known surface ices		CH4,N2,CO	H2O

Atmosphere			Confirmed	Unlikely

 
In article <jburton.757225474@aces20.acenet.auburn.edu>, 
jburton@acenet.auburn.edu (John E. Burton Jr.) writes...
> 
>	Does anyone know the current status of the Pluto fast flyby?  Is 
>it a definite mission, or is it just a maybe? 
 
It is still in the pre-project phase (meaning just a maybe).  Official
start authorization would be in 1996 at the earliest.
 
MESUR Pathfinder and NEAR have both gotten the official OK from NASA this year.
     ___    _____     ___
    /_ /|  /____/ \  /_ /|     Ron Baalke         | baalke@kelvin.jpl.nasa.gov
    | | | |  __ \ /| | | |     Jet Propulsion Lab | 
 ___| | | | |__) |/  | | |__   Galileo S-Band     | "Why must hailstones always
/___| | | |  ___/    | |/__ /| Pasadena, CA 91109 |  be the size of something
|_____|/  |_|/       |_____|/                     |  else?"   George Carlin 
 
In article <jburton.757225474@aces20.acenet.auburn.edu> 
jburton@acenet.auburn.edu (John E. Burton Jr.) writes:

>	Does anyone know the current status of the Pluto fast flyby?  Is 
>it a definite mission, or is it just a maybe? 
 
Just a maybe.  It's a year or two away from being ready to ask for major
startup funding.  It's currently getting a trickle of money to explore
options and check out technology.
 
Last I heard, the outlook was mixed.  The Powers That Be like the mission,
but they don't like the idea of paying for two Titan IVs to launch it.
The only other really suitable launchers -- not as good, but adequate --
are Proton and Shuttle/IUS, both of which present political problems
(although of rather different kinds).
-- 
Belief is no substitute                 | Henry Spencer @ U of Toronto Zoology
for arithmetic.                         |  henry@zoo.toronto.edu  utzoo!henry

re .49 (me)
    
>    At 40 *bits* per second and 400 Mbytes, it will take 971 days (ignoring
>    overheads) to return the data. Still I guess that after the fast flyby
>    it won't have much better things to do than dribble the data back.

    From 886.0 ...
    
    Nominal downlink rate is about 40 bits/second at Pluto encounter range to a
    34 m Deep Space Network (DSN) station.  A higher rate of ~160 bits/second
    is possible using the larger 70 m antennas of the DSN.

    ...return over a limited downlink (40 to 160 bps) via daily DSN passes for
    up to a year after the flyby

Article: 3725
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: alt.sci.planetary
Subject: Re: FIRE AND ICE
Date: 27 Jun 1994 15:18 UT
Organization: Jet Propulsion Laboratory
 
In article <1994Jun26.184755.7051@powertech.no>, jabrana@powertech.no
(Jabran Akhtar) writes... 

>Regarding the Pluto Fast Fly by mission :
> 
>Will there be two probes sent to the Pluto ? I thought another
>probe 'Fire and Ice' ,with the 'Ice' part was scheduled to go to Pluto.
 
"Fire and Ice" and the Pluto Fast Flyby are separate missions.
 
The original Fire and Ice mission was proposed about 5 years ago.  A
single probe would be launched towards Jupiter, and then separate into
two spacecraft.  One would use a Jupiter gravity assist towards Pluto
(Ice), and the other towards the Sun (Fire). 
 
The Pluto Fast Flyby missions consists of two spacecraft launched
directly to Pluto.  This mission is in its preproject phase with a new
start scheduled for 1996, pending approval from Congress. 

It looks like the launch vehicle will be the Proton provided by the
Russians.  A derivative of the Fire and Ice option has recently been
revived as a possible joint effort with the Russians. 

      ___    _____     ___
     /_ /|  /____/ \  /_ /|     Ron Baalke     | baalke@kelvin.jpl.nasa.gov
     | | | |  __ \ /| | | |     JPL/Telos      | 
  ___| | | | |__) |/  | | |__   Galileo S-Band | If you follow the herd, you
 /___| | | |  ___/    | |/__ /| Pasadena, CA   | will eventually end up in the
 |_____|/  |_|/       |_____|/                 | slaughter house.

From:	US1RMC::"baalke@kelvin.jpl.nasa.gov" "Ron Baalke" 13-SEP-1994 
To:	usenet-space-news@arc.nasa.gov
CC:	
Subj:	JPL, Russian Officials Discuss Mars & Pluto Missions

From the "JPL Universe"
September 9, 1994

JPL, Russian officials discuss `Fire,' `Ice,' `Mars Together'

By KARRE MARINO

   The third in a series of meetings between representatives from 
NASA, the Russian Space Agency and Russian Academy of Sciences in 
preparation for three joint missions occurred at JPL in late 
August, with each team making significant progress.

   The first two meetings, at JPL, and in Hamburg, Germany, helped 
the teams work out engineering details of the interface between 
U.S. and Russian parts. With this latest meeting, each of the 
three missions--Mars Together, Fire (the sun) and Ice (Pluto)--
``expanded and solidified the positive relationships that had been 
already established," according to Dr. Roger Bourke, Mars Together 
manager. 

   Under the Mars Together concept, the two nations would 
collaborate on a series of missions to the Red Planet, beginning 
in 1998 with two launches, one American and one Russian, with 
payloads of American and Russian spacecraft and instruments.

   For Mars Together, this third meeting saw the United States and 
Russia confirm "the baseline configuration of a Russian autonomous 
propulsion module, a Russian descent module (containing a balloon 
and rover) and an American orbiter launched by a Russian Proton 
rocket," Bourke said.

   Instrument exchange was discussed in depth, with the Russians 
offering 10 possibilities for an instrument on the U.S. orbiter. 
The Americans discussed possible instruments on the Russian 
Marsokhod rover and involvement in its operation. 

   The team will focus on hardware flow of the combined 
Russian/American vehicle at an October meeting in Moscow.

   No technical barriers preclude a '98 launch to Mars, Bourke 
explained, yet he conceded that "Some outstanding issues remain, 
including the Russian's financial ability to fund this joint mission."

   The financial question must be resolved within the next six to 
nine months, at which time the two sides must commit to an 
approved mission, he noted.

   The Fire mission, according to Fire manager Jim Randolph, will 
team two spacecraft, one built by Russia and one by JPL, both to 
be launched on a single Russian Proton launch vehicle in September 
2001 to study the Sun.

   "The Russians will build a new generation of lightweight 
spacecraft, no more than 350 kilograms (770 pounds), which is 
significantly lighter than previous Soviet spacecraft," Randolph 
said. The Russians are excited about the fact this will be the 
first Russian deep space spacecraft, he added.

   The proposed mission has the U.S. craft flying "to a 4 solar 
radii perihelion, and the Russian spacecraft flying to a 10 solar 
radii perihelion," he explained.

   U.S. instruments, said Randolph, will be mainly plasma sensors, 
while the Russians' will be mainly optical instruments.

   The Ice mission, according to Pluto Preproject Scientist Dr. 
Richard Terrile, builds on JPL's existing Pluto Fast Flyby 
preproject. Under the collaborative U.S.-Russian approach, JPL's 
twin Pluto spacecraft would be launched in 2001 on a Proton launch 
vehicle and would carry two small Russian-built atmospheric 
probes, called drop Zonds.

   He noted that this approach has the advantages of "clean 
interfaces that are easily defined and easy to work with."

   Science objectives and goals were also determined at this third 
meeting; payloads of both spacecraft are still being discussed.

   All three reports will be delivered to the Joint Working Group 
on Solar System Exploration in Moscow on Oct. 7, in preparation 
for meetings between Vice President Al Gore and Russian Prime 
Minister Viktor Chernomyrdin to be held in December.

   The next meetings will occur Sept. 20--by videoconference. 

                              ###