Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT/SPACEDIG/V13_4/V13_420.TXT

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Subject: SPACE Digest V13 #420

SPACE Digest                                     Volume 13 : Issue 420

Today's Topics:
         NASA Headline News for 04/17/91 (Forwarded)
             Re: Fred on the Moon
            Re: The first VOSTOK in space
             Re: NASA & Executive Branch
               Re: Earth/Moon formation
                 solar sails

Administrivia:

    Submissions to the SPACE Digest/sci.space should be mailed to
  [e-mail].  Other mail, esp. [un]subscription requests,
  should be sent to [e-mail], or, if urgent, to
             [e-mail]

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

Date: 17 Apr 91 17:31:46 GMT
From: [e-mail]  (Peter E. Yee)
Subject: NASA Headline News for 04/17/91 (Forwarded)


             Headline News
Internal Communications Branch (P-2) NASA Headquarters

  Wednesday, April 17, 1991    Audio Service: 202 / 755-1788

This is NASA Headline News for Wednesday, April 17, 1991 . . .

Atlantis made it as far as Columbus, Mississippi, yesterday on the
return flight from California following its STS-37 landing.  Because of its
late departure from Edwards Air Force Base, the 747 shuttle carrier
aircraft crew couldn't refuel in San Antonio and make it to the Shuttle
Landing Facility during the allotted daylight period.  Instead, they opted to
lay over at Columbus Air Force Base, and are expecting to leave this
morning for Kennedy Space Center.  There are some weather
concerns for the flight path near the Mississippi-Georgia border,
thunderstorms mostly.  However, the 747 crew expects to have Atlantis
back at Kennedy by early afternoon.

                   * * * * * * * * * * * * * * * *

Goddard Space Flight Center flight controllers report that instrument
turn-on began yesterday on the Gamma Ray Observatory.  At 11:29
am yesterday, the Oriented Scintillation Spectrometer Experiment
successfully detected charged particles as the spacecraft flew the South
Atlantic anomaly, a positive indication that the OSSE instrument is
alive and well.  Science operations with GRO are expected to begin the
third week of May.

                   * * * * * * * * * * * * * * * *

The Stennis Space Center reports that nearly 2,300 guests toured its
visitor center last week.  The center also notes that its Early Education
Monday, an innovative educational program for grade school children,
was conducted for 137 students from three schools in Picayune and
Kosciusko, Mississippi, and Lacombe, Louisiana.

                   * * * * * * * * * * * * * * * *

NASA yesterday issued a request for proposals to establish six
Regional Technology Transfer Centers to replace the ten
Industrial Applications Centers, whose contract expires this year.  This
restructuring is intended to upgrade and revitalize the current technology
utilization network and to broaden its geographical coverage.  The new
program also expects to forge new partnerships with state and local
government technology transfer centers and to establish close ties
with the NASA Centers for the Commercial Development of Space
in their respective regions.

                   * * * * * * * * * * * * * * * *

Marshall Space Flight Center commemorates the 10th anniversary of
the first flight of the shuttle this Friday with a special luncheon at the
Redstone Arsenal Officer's Club.  Honored at the luncheon will be
John Young and Robert Crippen, commander and pilot, respectively, of
the shuttle's pioneer mission -- STS-1.  Also honored will be individuals
from Marshall who, at that time, played a significant role in enabling
Columbia to take that historic first step, including then-Center Director
Bill Lucas, then-Center Deputy Director Jack Lee, then-Marshall
Shuttle Project Manager Bob Lindstrom, then-External Tank Project
Manager Jim Odom, and then-Solid Rocket Booster Manager George
Hardy.  Current Marshall Director Jack Lee will host the luncheon, which
starts at 12:00 pm EDT.  The press has been invited to cover the luncheon
and to interview participants following its close.


Here's the broadcast schedule for Public Affairs events on NASA Select TV.
All times are Eastern.  NASA Select TV is carried on GE Satcom F2R,
transponder 13, C-Band, 72 degrees W Long., Audio 6.8, Frequency 3960
MHz.

Wednesday, 4/17/91
    10:00 am    STS-40, Spacelab Life Sciences-1, live Joint Integrated
          Simulation between Marshall Space Flight Center and Johnson
          Space Center.  Simulation activities continue through 10:00 pm.

    1:15 pm    Magellan-at-Venus status report and science update live from
          Jet Propulsion Laboratory.

    1:30 pm    STS-40 Joint Integrated Simulation activities continue live
          from Johnson and Marshall centers.

Thursday, 4/18/91
    8:00 am    STS-40, Spacelab Life Sciences-1, live Joint Integrated
          Simulation between Marshall Space Flight Center and Johnson
          Space Center.  Simulation activities continue through 2:00 pm.

Friday, 4/19/91
    9:00 am    Senate Subcommittee on Science, Technology and Space
          (Albert Gore, D-Tenn, chairman) hearing on NASA Fiscal Year 1992
          budget request and findings of the Advisory Committee on the
          Future of the U.S. Space Program.  NASA Administrator Richard
          Truly and advisory committee chairman Norman Augustine are
          witnesses.  (This hearing will be covered live at the beginning, and
          picked up again in progress following the STS-37 briefing.  The
          entire hearing will then be replayed.)

    10:00 am    STS-37 flight crew post-mission press conference live
      from Johnson Space Center.  Mission commander Steve Nagel, pilot Ken
          Cameron, and mission specialists Jerry Ross, Jay Apt and Linda
          Godwin will describe their recent flight and show and narrate video
          highlights of the mission, which included two spacewalks.

    11:00 am    Continue live coverage of Senate Subcommittee hearing
      on NASA budget request.

    approx. 12:00 pm    Replay entire hearing of Senate Subcommittee on
          NASA Fiscal Year 1992 budget request and advisory committee
          findings.

All events and times may change without notice.  This report is filed daily,
Monday through Friday, by 12:00 pm, Eastern.  It is a service of NASA
Headquarters Office of Public Affairs.  Contact:  CREDMOND on
NASAmail or at 202/453-8425.

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

Date: 16 Apr 91 14:33:58 GMT
From: csus.edu!wuarchive!cs.utexas.edu!news-server.csri.toronto.edu!utgpu!watserv1!watdragon!watyew![e-mail]  (James Davis Nicoll)
Subject: Re: Fred on the Moon

In article <[e-mail]> [e-mail] (Doug Mohney) writes:
>In article <[e-mail]>, [e-mail] (Jose Pina Coelho) writes:
>
>>Other inconveniences:
>>  Supplies: the energy difference between getting them into low orbit
>>  and getting them to the moon is quite big.
>
>Sure, if you use conventional techniques. If you're not in a hurry (gosh, the
>moon will still be there), use a combination of solar sails and ion thrusters
>to move large cargos. Will take a bit longer, but your fuel costs are much
>less.

    The delta vee required will still be the same. With solar sails,
the sun provides the needed energy. With the ion thrusters, you need some
sort of power-plant to run the thing. Assuming you don't want to use a
chemical powerplant (of course), that means you need either a solar or nuclear
power source. Anyone know the current weight to power output of solar and
nuclear powerplants? Anyone know the *cost* per unit energy produced of
space-rated solar and nuclear powerplants (Assuming no wonderful technological
breakthrough in the near future)?

    A silly question: solar sails look frail. Is there a lowest orbit
below which a ss cannot be used because of tides ripping the shroud or
air resistance doing likewise?

    (Material deleted)

>>  Basicaly the startup cost is dozens/hundreds of times that of LEO.
>>  Politics, politics, politics ...
>
>Hundreds? No. Dozens. No. Some factor between 2 and 12 times the cost, yes.

    How are either of you obtaining your figures for probable cost?

                                James Nicoll

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

Date: 17 Apr 91 13:09:04 GMT
From: agate!bionet!uwm.edu!spool.mu.edu!think.com!hsdndev!cfa203![e-mail]  (Jonathan McDowell)
Subject: Re: The first VOSTOK in space

From article <[e-mail]>, by [e-mail] (Chris Jones):
> In article <[e-mail]>, George_Muzyka@kcbbs (George Muzyka) writes:
>>We all call the first Soviet Vostok manned spacecraft, piloted by Yuri
>>Gagarin in April 1961, VOSTOK 1.
> When Radio Moscow announced the launch, they referred to it simply as Vostok,
> with no number.  It wasn't until Vostok 2 that Gagarin's craft was called
> Vostok 1.

According to Soviet publications on the design of Vostok, there were
two test variants Vostok A and Vostok B, with Vostok V (3rd Cyrillic letter)
being the piloted variant used by Gagarin. I'm not sure how these variants
map on to the Korabl'-Sputnik series, and I'm puzzled by the reference to
Gagarin's Vostok as VOstok A3. Interesting. Chris is quite right about
the lack of number on Gagarin's Vostok. Even today the Soviets call it
Vostok rather than Vostok 1; this is standard Russian practice.

Bear in mind that US spacecraft have serial numbers as well as their
official names; e.g the Mercury program sequence was Mercury
spacecraft 7 (Shepard), 11 (Grissom), 13 (Glenn), 18 (Carpenter), 16 (Schirra)
and 20 (Cooper); the A3 designation may be a similar factory serial
sequence independent of the flight name sequence.

- Jonathan McDowell

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

Date: 17 Apr 91 13:35:01 GMT
From: agate!bionet!uwm.edu!rpi!uupsi!pbs.org![e-mail]
Subject: Re: NASA & Executive Branch

In article <[e-mail]>, [e-mail] (Alan Parker) writes:
> In article <[e-mail]>, [e-mail]
> (Henry Spencer) writes:
>> Apart from the difficulty of getting such a forthright order out of any
>> recent president :-(, alas, no.  Checks and balances.  The President can
>> order NASA to do it, but only Congress can authorize spending money on it.
>
>
> Does it bother others that so many don't seem to understand how our
> government works?   We shouldn't expect everyone around the world to
> understand the limits of a President and the role of Congress; but
> certainly every American kid in school is taught about these things.
> If Henry has to start telling posters how our government works, then we are
> in big trouble.   I'm sure few of us can tell him how his works!
I AM  well aware of what the textbooks say about how our government is supposed
to work.  Having grown up inside the beltway around the nation's capital I also
have a sense for how it actually works.  The name of the came is Power and if
you can get away with it, you do it.  The involvement in Central America, for
example, did not go exactly by the book. :-)

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

Date: 18 Apr 91 03:31:08 GMT
From: agate!bionet!uwm.edu!cs.utexas.edu!news-server.csri.toronto.edu!qucis![e-mail]  (Richard Akerman)
Subject: Re: Earth/Moon formation

In article <[e-mail]> [e-mail] (Phil OKunewick) writes:
>   Several theories had been proposed about the earth/moon formation.
>The capture theory is plausable, though highly unlikely.  In order for
>the moon to have been captured, another massive celestial body would
>have had to pass about the same time.  Chances of that happenning are
>slim; chances of it causing this almost-round orbit are even slimmer.
>The orbit also seems to follow the solar plane (unlike pluto); chances
>of this occurring are slimmer still.  Throw in the moon samples, and
>throw this theory out.  The earth and moon had to be related in creation.
>
>   The moon-split-off-from-earth theory is more likely, though still
>would probably require a celestial body passing.  Again, the orbit is
>awfully circular, which I suspect is unlikely.  But this still doesn't
>explain how the earth formed in the first place.

Let's be clear here.  There is the fission theory, which proposes that the
Moon is formed of material spun off the outer layers of the Earth.  This
theory does not explain where the energy came from to lift these particles
off.  Then there is the impact-trigger hypothesis, which says that the Moon
was formed when Earth was hit by a very lage interplanetary body, blasting
material from the Earth's crust and mantle into orbit which then aggregates
to form the Moon.  This picture ties in well with the hypothesis that the
Earth was formed by the binary accretion of swarms of planetesimals (with
a runaway phase of rapid growth at the end).  You state that you suspect
that the high circularity of the Moon's orbit is unlikely.  Why?  If swarms
of particles orbiting the Sun settle into low-eccentricity orbits then
why not particles orbiting the Earth?
>
>   My favorite theory is that there was a ring of dust/gas orbiting
>the sun which had some eddys in it.  The matter in these eddys
>collected more matter until they became solid objects (planets and
>moons).  This allows for the rock to solidify around 4.5 billion years
>ago, and assuming that this area of the oribiting dust ring contained
>similar matter throughout, it allows for earth and moon rocks to be
>the same composition.
>
>
>   Now, my skills in geology are strictly ameteur [sic].  Can anybody shed
>more evidence/theories on this event?  How about why we never see the
>back of the moon - what would cause the moon's mass to be that offset?

Ok, the usual picture of Solar System formation is that by one process or
another we get rocky planetesimals of roughly 10 km diameter forming out of the
primordial dust nebula.  These
planetesimals in turn collide with one another and form larger embryonic
planets.  A few of these bodies will experience runaway growth at the
expense of the others, forming the planets.

The currently favoured hypothesis for lunar formation is the impact-trigger
hypothesis.  It explains a number of things about the composition of the
Moon by positing that a large (perhaps Mars-sized) body impacted the Earth
at a late stage of planetary evolution.

Other theories are the fission theory mentioned above, the co-accretion theory
which you favour above and the capture theory.  Each of these has some
problematic flaws.

You see, we know from the Moon rocks that its composition is similar to the
Earth's, except it has much less iron.  This suggests that the Moon was formed
from material similar to the Earth's mantle, except that it is depleted in
volatile materials (material such as water that is driven off by heating) and
enhanced in refractory elements (elements with high boiling points).  This
suggested that the lunar material was subjected to strong heating before or
as it formed.

We can then turn to the formation hypotheses.  The fission theory has the
problems mentioned before.  The co-accretion theory does not explain how
the Moon could have formed near the Earth but been depleted in iron.  The
capture theory does not explain where the Moon could have come from in
order to have its low-iron composition.

The impact theory seems to account for these problems.  The Moon would be
depleted in iron because by then the Earth would have undergone differentiation
and most of its iron would have sunk to the core.

As for the question of the Moon presenting only one face to the Earth, this
indicates a bit of confusion.  The process by which this occurs is called
tidal locking, and is a very common process in the Solar System.  In fact,
most moons exhibit this same property of presenting only one face to the
planet which they orbit.  Basically, the Moon is demonstrating synchronous
rotation.  It is rotating in its orbit in such a way as to always present
the same face towards the planet.  It has been shown that if the Moon had
one axis that was longer than the other, it would tend to want to align this
axis so that it always pointed towards the Earth.  Since the gravitational
field of the Earth causes it to raise a body tide on the Moon that
elongates it in one direction, the Moon thus eventually enters this tidal
lock with the Earth and we see only one side.

All of this material discussed much more clearly than I can manage in most
astronomy textbooks.  I would recommend

Hartmann, W.K.  (1989).  _Astronomy: The Cosmic Journey_  (Belmont:
    Wadsworth Publishing Co.)

If you want to know about the formation of the Earth (but not the Moon) in
detail, try

Wetherill, G.W.  (1990).  Formation of the Earth.  _Ann. Rev. Earth Planet.
    Sci._ 18, 205-256.

Richard Akerman
Incompetent Physics Graduate Student
[e-mail]/ Akerman@QUCdnAst/ "Ban vi"

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

Date: 16 Apr 91 15:47:10 GMT
From: agate!bionet!uwm.edu!zaphod.mps.ohio-state.edu!rpi!news-server.csri.toronto.edu!utzoo![e-mail]  (Henry Spencer)
Subject: solar sails

In article <[e-mail]> [e-mail] (James Davis Nicoll) writes:
>    A silly question: solar sails look frail. Is there a lowest orbit
>below which a ss cannot be used because of tides ripping the shroud or
>air resistance doing likewise?

The forces involved are minor compared to the strength of materials, at
least for existing sail designs.  The major altitude constraint is air
drag.  Below about 1000km, a conventional solar sail is useless for
propulsion because velocity loss from air drag exceeds velocity gain
from light pressure.

One devious way around this is to punch the sail full of holes on a scale
substantially smaller than the wavelength of visible light.  The air
molecules go straight through, but light still reflects.  The sail is also
lighter, of course.  It's just a lot harder to make...
--
And the bean-counter replied,           | Henry Spencer @ U of Toronto Zoology
"beans are more important".             |  [e-mail]  utzoo!henry

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

End of SPACE Digest V13 #420
*******************