Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT/SPACEDIG/V13_5/V13_536.TXT

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Subject: SPACE Digest V13 #536

SPACE Digest                                     Volume 13 : Issue 536

Today's Topics:
     Space Sience vs Space Engineering. Will AXAF be cut
             Re: Another Galileo Sulution
               Re: Saturn V and the ALS
         Re: Laser launchers (really tethers)
        Re: Terraforming Mars?  Why not Venus?
       Science vs. Exploration (was Re: Why the space station?)
       Re: Ethics of Terraforming (was Re: Terraforming Venus)
         Re: Why the space station? (Really Docking)
             New CD-ROMs on-line at Ames

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: 8 May 91 00:45:01 GMT
From: mintaka!think.com!rpi!usc!jarthur!nntp-server.caltech.edu![e-mail]  (Steinn Sigurdsson)
Subject: Space Sience vs Space Engineering. Will AXAF be cut


    Word is going around that in the next week Congress
will decide the immediate future of the US space program, the
choice being between cancelling or delaying Space Station Fred
and retaining AXAF, SIRTF and the space science program, on the
one hand, or going ahead with Fred, and cancelling or delaying
AXAF, SIRTF and other space science programs. As I understand it,
no money can be moved into the appropriations category NASA comes
under, and with the VA and HUD competing for funds, something will be cut
to balance the budget - and it will not be the VA.

    The Astronomy community is asking scientists to write
congress to express their opinion on the issue. ie Tell them
to cut Fred. Personally I would hate to see the Space Station cut,
but in a straight choice between AXA/SIRTF and Fred would choose
AXA/SIRTF. The Space Station is not currently justified
scientifically, although I think it is an excellent engineering
project, and even more important at the motivational level so recently
derided in "What's New in Physics".

    I would ask people to take a few minutes to write to congress
and express their opinions on the issue - even if you disagree.


Addresses provided by J. Bahcall:

==========================================================================

HOUSE:

APPROPRIATIONS COMMITTEE
SUBCOMMITTE on HUD \& Independent Agencies

Democrats                             Republicans

Bob Traxler, MI, CHAIRMAN             Bill Green, NY, RANKING MIN.
Rm. 2366 Rayburn House Office Bldg.   Rm. 2301 Rayburn House Office Bldg.

Louis Stokes, OH                      Lawrence Coughlin, PA
Rm. 2365 Rayburn House Office Bldg.   Rm. 2309 Rayburn House Office Bldg.

Alan Mollohan, WV                     Bill Lowery, CA
Rm. 229 Cannon House Office Bldg.     2433 Rayburn House Office Building

Jim Chapman, TX
236 Cannon House Office Building

Chet Atkins, MA
123 Cannon House Office Building

Marcy Kaptur, OH
1228 Longworth House Office Building


Staff: Richard Malow
       H 143 The Capitol


All addresses are Washington D.C. 20515

===============================================================================


===============================================================================

SENATE

APPROPRIATIONS COMMITTEE
SUBCOMMITTEE: HUD and Independent Agencies

Democrats                                Republicans

Barbara Mikulski (MD), CHAIRMAN          Jake Garn (UT), RANKING MIN.
Rm. 320 Senate Hart Office Bldg.         Rm. 505 Senate Dirksen Office Bldg.

Patrick Leahy (VT)                       Alfonse D'Amato (NY)
Rm. 433 Senate Russell Office Bldg.      Rm. 520, Senate Hart Office Bldg.

J. Bennett Johnston (LA)                 Don Nickles (OK)
Rm. 136 Senate Hart Office Bldg.         Rm. 713 Senate Hart Office Bldg.

Frank Lautenberg (NJ)                    Phil Gramm (TX)
Rm. 506 Senate Hart Office Bldg.         Rm. 370 Senate Russell Office Bldg.

Wyche Fowler, Jr. (GA)                   Kit Bond (MO)
Rm. 204 Senate Russell Office Bldg.      Rm. 293 Senate Russell Office Bldg.

J. Robert Kerrey (NE)
Rm. 316 Senate Hart Office Bldg.


STAFF: Kevin Kelly
       142 Senate Dirkson Office Building

All addresses are Washington D.C. 20510


===============================================================================

Phone numbers: Congressman Traxler: 202-225-2806
               Senator Mikulski:    202-224-4654

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

Date: 29 Apr 91 17:17:57 GMT
From: news-server.csri.toronto.edu!utzoo![e-mail]  (Henry Spencer)
Subject: Re: Another Galileo Sulution

In article <[e-mail]> [e-mail] writes:
>Although putting a communications relay satellite in orbit around Jupiter
>is a good idea, one must remember that Jupiter's position changes during
>it's year, sometimes making it even further away from Galileo than Earth
>would be.

Uh, how is this relevant?  We don't care (that much) about the data
Galileo will be sending until it too is in Jupiter orbit.  Despite some
small side trips along the way, Galileo's mission in life is to be a
Jupiter orbiter.

>Another possibility would be to launch a relay station into a trajectory
>aimed directly at Galileo, thus the relative position between it and
>Galileo remain unchanged. Relay-1 can then take on the task of tracking
>Earth. ...

Unfortunately, this means Relay-1 also has to be able to receive from
Galileo.  The whole point of putting a relay into Jupiter orbit is that
it will be *close* to Galileo, so it can get a decent data rate without
needing a large antenna and precision pointing.  A small spacecraft
halfway between Earth and Jupiter is not going to be able to compete
with DSN's huge ground-based antennas with liquid-helium-cooled maser
amplifiers.  Doubling the distance only cuts the signal strength by
a factor of 4, and DSN's massive equipment performs better than a small
relay satellite by a far larger margin than that.  Relay satellites make
sense only in Galileo's odd situation, and only if they are orders of
magnitude closer to Galileo than Earth is.
--
And the bean-counter replied,           | Henry Spencer @ U of Toronto Zoology
"beans are more important".             |  [e-mail]  utzoo!henry

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

Date: 8 May 91 19:31:38 GMT
From: dog.ee.lbl.gov!hellgate.utah.edu!caen!ox.com!hela![e-mail]  (Allen W. Sherzer)
Subject: Re: Saturn V and the ALS

In article <[e-mail]> [e-mail] writes:

>> But this number is interesting. Two contractors have offered to build
>> for a fixed price launchers which will launch 100K pound payloads. They
>> will do it in half the time and 5% of the cost of ALS. Operational costs
>> of these launchers would be about the same as ALS.

>5 % ? who are the contractors? what are their track records ?
>I'll believe it when I see it.  "There aint no such thing as a free lunch."

The contractors are McDonnell Douglas and Martin Marietta. Both vehicles are
heavy lift versions of their existing launchers. In both cases something
like 95% of the launchers consists of off the shelf parts. Both have offered
to build the vehicle under a commercial acquisition for a fixed price.

For more information see my last three "One Small Step..." collumns or
the Sept. 1990 issue of Aerospace America.

These vehicles will meet NLDP operaitonal cost yet cost less than one
Shuttle flight to build.

  Allen
--
+---------------------------------------------------------------------------+
|Allen W. Sherzer |        Allen's tactics are too tricky to deal with      |
|   [e-mail]   |             -- Harel Barzilai                           |
+---------------------------------------------------------------------------+

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

Date: 8 May 91 19:56:18 GMT
From: aio!ecfa![e-mail]  (Michael C. Matthews)
Subject: Re: Laser launchers (really tethers)

In article <[e-mail]> [e-mail] (Gary Coffman) writes:
>In article <[e-mail]> [e-mail] (Nick Szabo) writes:
>>In article <[e-mail]> [e-mail] (Gary Coffman) writes:
>>>Tethers need to exceed the theoretical strength of materials limits by
>>>orders of magnitude to work.
>>
>>Kevlar can work today for most of the scenarios envisioned.
>>The major problem is launch cost of the mass.  This can be brought
>>way down by (a) manufacturing the tethers in space, (b) producing
>>better tensile materials -- a very important and woefully underfunded
>>field of R&D, (c) bootstrapping larger tethers into orbit with smaller
>>tethers, or (d) a combination of the above.
>
>A one square inch kelvar tether to geosync orbit would weigh 45.2 million
>pounds. I don't have the handbook here at the terminal, but kelvar doesn't
>approach 45 million pounds per square inch tensile strength by orders of
>magnitude. It couldn't support itself, much less a usable payload.
>

Please don't confuse "tethers" with "beanstalks": the latter is a
special case of the former and is generally considered to be centuries
(or at least several decades) away from practicality, while tethered
satellite technology is ready to fly next year (assuming the shuttle
schedule holds).  There are many applications of tethers in the 1-km
to 1000-km range that provide much promise for momentum scavenging/
transfer/banking and electrodynamic energy storage applications, which
could be practical in the next decade or two.  For these kinds of
tether lengths, Kevlar is quite adequate, and stuff like Spectra is
great for "disposable" tethers.  I do have to admit to some doubts
about being able to drastically reduce launch costs with such systems,
due to their operational and dynamic complexity.  I imagine that
scheduling for a "rolling skyhook" system would be a nightmare, and
prox ops would be... uh... "dramatic".

--
Mike Matthews                   [e-mail]
Tethered Vehicle Analysis Group, Advanced Projects Section
Navigation, Control, and Aeronautics Department
Lockheed Engineering & Sciences Company, Houston, Texas

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

Date: 9 May 91 04:18:09 GMT
From: mintaka!ai-lab!life.ai.mit.edu![e-mail]  (Guest Account)
Subject: Re: Terraforming Mars?  Why not Venus?

In article <[e-mail]> [e-mail] (Frank Crary) writes:

>The idea of a skintight suit (the Space Activity Suit was the name of the
>only real design, and didn't work too well.) is all about how the pressure
>s maintained. It has nothing to do with thermal control.

The Space Activity Suit doesn't have a cooling system. The wearer
cools himself as his sweat passes through the gore-tex.

And besides, the SAS was promising. it would probably be better than
the ones in use today if the same inordinate amount of money was thrown
at it.

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

Date: 9 May 91 05:01:59 GMT
From: rochester!sol![e-mail]  (Brian Yamauchi)
Subject: Science vs. Exploration (was Re: Why the space station?)

In article <[e-mail]> [e-mail] (Robert W Murphree) writes:

>[e-mail] (Henry Spencer) writes:

>>In article <[e-mail]> [e-mail] (Robert W Murphree) writes:
>>>...  I see no signs that the
>>>exploration of the solar system is really limited by the lack of an
>>>orbital base.  There is an IMMENSE amount of science that can be done
>>>with present technology...

>>You are assuming that "science" and "exploration" are synonymous; care to
>>explain this?

>what I mean by exploration is discovering the story of the origin of
>planets of life, the nature of the mantle and accretion on other solar
>system bodies, how the earth was formed, how it works.

All of these are worthwhile questions; some may be answered through
exploration; but none *are* exploration.

Columbus wasn't doing science, and neither were Lewis and Clark.
Einstein and Newton weren't doing exploration.

In space, the two fields overlap greatly, but it's a mistake to get
them confused.  Sending Voyager to Neptune is exploration -- analyzing
the atmospheric currents on Neptune is science.  They are closely
related, but they are not the same thing.
--
_______________________________________________________________________________

Brian Yamauchi                University of Rochester
[e-mail]        Department of Computer Science
_______________________________________________________________________________

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

Date: 10 May 91 23:09:32 GMT
From: pyramid![e-mail]  (Lon Stowell)
Subject: Re: Ethics of Terraforming (was Re: Terraforming Venus)

In article <f28g5=[e-mail]> [e-mail] (Jim Kasprzak) writes:
> The point is, even if we manage to terraform Mars,........
>........................ If it were up to me, I'd designate
>Olympus Mons and the other Tharsis volcanoes as permanent wilderness
>areas, along with most of Valles Marineris. That's a pretty big
>chunk of the planet, but it still leaves a lot for human habitation.
>


But what about the face?  (Does anyone else think it sorta looks
like Maggie Thatcher?)

If I recall the strange martian chemistry, unless the human
habitats are kept sealed such that no H20 gets into the martian
atmosphere, there would likely be some chemical reactions that
may destroy some of the natural features.

Having a whole planet as a park?  Why not?   If we have the
engineering resources to terraform, we would also have the
ability NOT to do so, but still create quality life areas for
our future population--which i still predict will slow down its
growth as education and lifestyle choices become more widely
available.

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

Date: 10 May 91 03:12:18 GMT
From: wuarchive!rex!rouge![e-mail]  (Fraering Philip)
Subject: Re: Why the space station? (Really Docking)


Also, the Soviets use a different sort of docking approach than NASA
spacecraft have. They supposedly do this to save fuel. I think Henry
posted the details a while back.


--
Phil Fraering
[e-mail]
''It's a Flash Gordon/E.E. Smith war, with superior Tnuctip technology
battling tools and weapons worked up on the spot by a billion Dr.
Zarkovs.`` - Larry Niven, describing the end to _Down in Flames_.

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

Date: 30 Apr 91 00:00:03 GMT
From: [e-mail]  (Peter E. Yee)
Subject: New CD-ROMs on-line at Ames

Two new CD-ROMs are now available for anonymous ftp.  The first is
Volume 3 of the Voyagers to the Outer Planets series.  This contains
Uranus images, including the all images in the browse format (200 x 200).
I suggest that you get browse images first and then record the names of
the images that you would like to retrieve in full size.  Not all full size
images are on this disc.  Each of these two discs contains browse images for
about 2 other discs.  The second disc that is on-line is Volume 12 of the
Voyagers series and contains Neptune data, again including browse-sized
images.  Technical, machine readable descriptions of the discs may be found
in the file called voldesc.sfd on each disc.

And I would like to reiterate my earlier request that if you do use this data
in any report, publication, or formal presentation, that you make the following
credits:

For Voyager data:

Dr. Bradford A. Smith

For Magellan data:

Dr. Gordon H. Pettengill

And for all data:

Planetary Data System
National Space Science Data Center

Enjoy!

                            -Peter Yee
                            [e-mail]
                            ames!yee

PS For those of you who missed the details of how to access these discs, you
need to use anonymous ftp to ames.arc.nasa.gov.  The CD-ROMs are mounted as
/pub/SPACE/CDROM and /pub/SPACE/CDROM2.  Use of the first CD-ROM drive is
courtesy of Randall Robinson, Communications Operations Branch, NASA Ames
Research Center.

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

End of SPACE Digest V13 #536
*******************