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Subject: SPACE Digest V12 #143

SPACE Digest                                     Volume 12 : Issue 143

Today's Topics:
        Re: A report on Giotto's earth swingby
          Re: space news from June 11 AW&ST
          Re: Voyager Images Reveal New Saturn Moon
        Exobiology symposium at NASA Ames (150 lines)
            Re: Balloons, anyone?

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----------------------------------------------------------------------

Date: 28 Jul 90 11:17:37 GMT
From: eru!luth!sunic!mcsun!unido!mpirbn![e-mail]  (Daniel Fischer)
Subject: Re: A report on Giotto's earth swingby

In article <[e-mail]> [e-mail] (Chris Jones) writes:
>In article <[e-mail]>, p515dfi@mpirbn (Daniel Fischer) writes:
>>It was an absolute first in space history: a spacecraft returning to earth from
>>the depths of the solar system, to receive a gravity assist for a new job...
>
>I suppose it comes down to nitpicking as to what is meant by "the depths of the
>solar system", but the International Cometary Explorer (ICE, nee IUE or
>something), which made a pass at comet G-Z (I'm not even going to try to
>remember how to spell it) came from its stationkeeping position near one of the
>Earth/Sun Lagrangian points (L1 I believe: the one between us) and made 5
>flybys of the earth and/or moon to get its boost on its way to the comet.

I had also thought about ICE, but I guess the ESA people were thinking of these
famous 'spheres of influence'. And while ICE went pretty far from Earth and
Moon, it was still controlled mainly by their gravity. Giotto, on the other
hand, had been in a really heliocentric orbit and came back from there - that's
the difference. Anyway: it was good to have had some space news to cheer about
in those bleak early-July days...

        [e-mail] = Daniel Fischer
                               - just back from the cloudy Finland eclipse...

P.S.: The Halley encounter was on 14 March 1986, not 1990, but who would have
      forgotten this historic date     :-)

------------------------------

Date: 27 Jul 90 12:21:26 GMT
From: sdd.hp.com!uakari.primate.wisc.edu!nic.MR.NET!kksys!wd0gol!newave![e-mail]  (John A. Weeks III)
Subject: Re: space news from June 11 AW&ST

In article <[e-mail]> [e-mail] (Tony Wesley) writes:
> First [e-mail] (Henry Spencer) writes:
> >>> Total Voyager pricetag so far, including launches, is $865M.  Another $30M

> Then [e-mail] (michael.a.weinstein) writes:
> >>About the price for a single B2 bomber (this is so mind boggling that I

> And [e-mail] (Michael V. Kent) writes:
> >Actually, about the cost of 3 B2's.

> The cost of the B-2 will be about 800 million per airplane.

The price of the B-2 depends mainly on your accounting method.  The program
has about $22-Billion sunk into R&D so far.  If you allocate this 22G evenly
to each plane produced and assume a full production run, you get a figure
around $800-Million.  If you consider the $22-Billion to be a sunk cost,
then each plane would cost only about $235-Million (according to Newsweak).

Depending upon how you allocate the R&D money and the length of production
run that you assume, one can argue just about any price for a B-2.

-john-

--
===============================================================================
John A. Weeks III               [phone]               [e-mail]
NeWave Communications                ...uunet!rosevax!bungia!wd0gol!newave!john
===============================================================================

------------------------------

Date: 28 Jul 90 21:46:42 GMT
From: mejac!orchard.la.locus.com!prodnet.la.locus.com!proxima.la.locus.com![e-mail]  (Chris Davis)
Subject: Re: Voyager Images Reveal New Saturn Moon

In article <[e-mail]> [e-mail] (Ron Baalke) writes:
>NEW MOON DISCOVERED ORBITING PLANET SATURN
>     A new moon orbiting planet Saturn has been discovered by Dr.
>Mark Showalter, a researcher at NASA's Ames Research Center,
>Mountain View, Calif.  [...]
>The new moon has a diameter of only 12 miles
>and is temporarily designated 1981S13.  It orbits in the major
>gap, known as Encke's gap, in Saturn's outermost major ring, the
>"A" ring.  [...]
>     Now Saturn's smallest known satellite, the moon pushes
>material away from its orbit and is believed to cause the 200
>mile-wide Encke's gap.

My learned associate Dr. Gil Beyda at the Galactic Graffiti Computing
Corporation is impressed with the discovery of 1981S13 but has voiced
some concern about the damage that it is doing to Saturns "A" Ring.

Dr. Beyda has expressed his belief that a couple of large nukes would
be sufficient to eliminate this cosmic vandal and save the "A" ring
from further damage.  Unable to ignore their social conscience, Dr.
Beyda and several others have formed the Galactic Graffiti Foundation
to raise funds for the project.  We do not feel that it is sufficient
to be concerned merely with terrestrial ecology.

Please send your donation to Dr. Gil Beyda at the Galactic Graffiti
Foundation, P.O. Box 3468, Los Angeles, CA 80036.  All who donate a
gift of $100 or more will receive a free full color "I Nuked 1981S13"
button and a personal reply from Dr. Beyda.  This is a rare opportunity
to make your own personal mark on the solar system, so don't delay.

------------------------------

Date: Sat, 28 Jul 90 19:50:28 EDT
From: John Roberts <[e-mail]>
Disclaimer: Opinions expressed are those of the sender
    and do not reflect NIST policy or agreement.
Subject: Exobiology symposium at NASA Ames (150 lines)


>From: sun.udel.edu![e-mail]  (Andrew Salamon)
>Subject: Re: NASA Headline News for 07/25/90 (Forwarded)

>>An Exobiology symposium is scheduled to be held today at NASA's
>>Ames Research Center.  Topics up for discussion include the
>>existence of animal or vegetable life on Mars.  The briefing will
>>be replayed on NASA Select TV on Friday, July 27 at 1:00 P.M.
>>EDT.
>Could some kind soul who has access to NASA select and is interested in
>watching this please post a summary of the symposium?  Who presents
>talks, what the topics are etc.

>[e-mail]

Well, I'll give it a try. (Please forgive any misspellings. They didn't flash
any names on the screen, and the sound quality was not too great, so some of
the names could be way off.)

............................................................................
NASA EXOBIOLOGY CONFERNCE (sic)
News Briefing
Ames Research Center
July 25, 1990
Subject: Chemical Evolution and the Origin and Evolution of Life
Introductory speaker: Diane Stanley of NASA Ames
Format: This was indeed a news briefing, in which the topics of the conference
  were described to members of the press. There were six principal speakers,
  each to talk for about five minutes, after which there was a question and
  answer session.

 -- Dr. John Rommel[?], head of NASA's exobiology program at NASA Headquarters:
Exobiology looks at the mechanism of the origin of life, and investigates the
possible distribution of life on other planets and elsewhere in the universe.
Studies include information from existing and planned space probes, sample
return missions, etc. The search for extraterrestrial intelligence can be
considered part of this field of research.

 -- Dr. Carl Sagan, director of the laboratory for planetary studies at Cornell:
An area of great interest is the search for the origin of the chemical building
blocks of life. Voyager's inspection of Titan revealed the presence of a great
number and variety of small organic molecules. In experiments on Earth, the
basic atmosphere of Titan (nitrogen and methane) was reconstructed, and
bombarded by electrons, as Titan is thought to be bombarded. The results
appear to closely match what is seen on Titan, therefore it is felt that the
mechanism by which the organic molecules are formed is fairly well
characterized. Since many of these molecules will tend to precipitate out
of the atmosphere, it is thought that the surface [at a temperature of 95K?]
now has a thick coating of organic matter. An interesting characteristic of
some of this matter is that if it is dropped in water, it will form amino acids.

A separate question was the likely origin of the first (prebiological) organic
matter on Earth. It was decided that if the early Earth had a reducing
atmosphere, then the likely source of most of the organic matter was local
formation (lightning, etc.) If the early atmosphere was neutral, then the
odds are that most of the first organic matter came from off-planet (asteroids,
comets, etc.)

 -- Dr. Stanley Aramit [?], UC at Santa Barbara, professor of geology:
Concerning the earliest life on Earth: once it was present, in what ways and
at what rate did it evolve? This question has led to a search for the oldest
examples of life. In Australia, rocks have been found which are 3.5 billion
years old, and which contain 3d fossils of microbes. Another test for life is
the identification of particular patterns in the sediment which are produced
by microbes - called stromatolites [?]. It is thought that life was first
present 4 billion years ago. The 3.5 billion year old fossils show advanced
capabilities such as photosynthesis, indicating that there had been rapid
divergence and development over the previous 500 million years. Microbes
continued to dominate the biosphere over the next 3 billion years.

 -- Dr. David Iva[?] [Ray?], biogeochemist at NASA Ames:
A study of natural materials such as rocks has led to the discovery of
"chemical fossils", which are the residual chemical evidence of life. [This
could include organic molecules, parts of organisms, waste products, minerals
which have been changed by exposure to the chemical influences of life, etc.]
Chemical fossils can often be identified by chemical testing, which is easier
than close inspection. They may also be much more abundant than fossils of
the organisms themselves.

Looking at the early history of the earth, it appears that carbon fixation and
photosynthesis were in use 3.5 billion years ago. There is evidence of major
atmospheric changes at specific times, including a rapid rise in O2 content
from 1% to 15% about 1.9 billion years ago, and a decline in CO2 about 1-2
billion years ago from 1% to 0.1% (now .03%).

 -- Dr. Robert Wharton [?], visiting senior scientist at NASA Headquarters:
While there is no evidence of life on Mars now, it is possible that life did
arise on Mars in the distant past, when conditions are thought to have been
more favorable for life. It is thought that there was considerably more
atmosphere, and liquid water, possibly forming lakes the size of the Great
Lakes, in which life could have survived. In addition to providing water and
regulating temperature, the lakes could have built up concentrations of
dissolved gases needed for life. As conditions changed [loss of atmosphere,
lower temperatures], the lakes would have iced over, and remained that way
for some time before disappearing.

It is felt that if these lakes existed and can be found [i.e. by Mars
Observer], a close inspection of the material of the old lake beds would
have about the best chance of finding evidence of life. While waiting for
better Mars surveys and rovers, we can practice some of the basic techniques
in Antarctica.

 -- Dr. Harold Klein [NASA?]:
Summary: a wide range of topics are discussed at the conference, including
stellar evolution, biochemistry, geology, computer models, field biology.
Tools of exobiology include microscopes, telescopes, laboratory equipment,
and spacecraft. A fundamental question to be addressed: how did life arise
on this planet?

...........................................................................
Highlights from question and answer session:

 - Sagan: There's lots of organic matter in the solar system, and he thinks
     many stars (maybe most) have planets. His opinion is that there are
     probably lots of worlds with life & intelligence & technology, and that
     some of them may be beaming messages to us. He is quick to point out
     that this is just an opinion (no effort to use Drake's Equation), but
     he does consider SETI important. He may make an effort to persuade
     Congress that SETI is worthwhile, and that the NASA plan is sensible
     and comprehensive. He thinks that even if it has funding setbacks in the
     near term, someone will do it eventually. The results of a good SETI
     program would be valuable, regardless of whether anything is found
     or not.

 - If ancient lake beds are found on Mars, they would like to locate
     outcroppings (original surface exposed) and look for the stromatolites[?]

 - The surface of Mars is now highly hostile to life - among other things, the
     soil is strongly reactive. It is therefore highly unlikely that there is
     anything living on Mars that gets its energy from photosynthesis. However,
     it is conceivable that there are organisms still alive on Mars, associated
     with hydrothermal activity. It is therefore a priority to determine
     whether there is any outgassing or hydrothermal activity on Mars. The
     Mars orbiter can search for thermal discontinuities.

 - It is possible that life arose and was wiped out several times on the earth,
     before becoming firmly established. If this is ever found to be true, it
     would improve the calculated odds that life could have arisen independently
     on many worlds.

[Disclaimer: I may have misinterpreted the views of some of the participants.
This is a brief summary, not a transcription.]
        John Roberts
        [e-mail]

------------------------------

Date: 28 Jul 90 14:07:06 GMT
From: usc!cs.utexas.edu!samsung!emory!wa4mei!ke4zv![e-mail]  (Gary Coffman)
Subject: Re: Balloons, anyone?

In article <[e-mail]> [e-mail] (Walter Santarelli) writes:
>The benefits gained by launching a rocket from high altitude balloons
>may be mitigated by guidance initialization problems. In the 1970's, a
>plan to air launch MX missiles from cargo planes was examined as a
>cheap deployment technique. The missile was to be dropped from the
>plane on a parachute and fired when the plane was at a safe distance.
>The program was not successful in achieving accurate trajectories due
>to initialization errors. The problems associated with shifting winds
>and oscillations in altitude and speed introduced too many unknowns.
>The project was abandoned after some test firings. Balloons may
>introduce the same sorts of problems. I don't know if orbital
>insertion is as demanding of accurate trajectories as ICBM's, but I
>would guess that the errors introduced by the balloon would make this
>a very difficult problem.

Perhaps not. The balloon will be at a steady state altitude when the
launch occurs and can remain there for some time if new guidance fixes
are needed. Also, the onboard guidance systems of a civilian flight
can use navigational satellites and ground stations to obtain a fix.
The military launches were for a falling object with only a few seconds
to orient itself and the missle could not use outside navigational
signals since the military could not depend on them surviving in a
crisis. So civil launches from balloons look much more practical.

Gary

------------------------------

End of SPACE Digest V12 #143
*******************