Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT/SPACEDIG/V13_5/V13_598.TXT

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Subject: SPACE Digest V13 #598

SPACE Digest                                     Volume 13 : Issue 598

Today's Topics:
       Re: NASA Headline News for 05/20/91 (Forwarded)
          Re: space news from March 18 AW&ST
          Re: SPACE STATION FREEDOM WOUNDED
         Re: New Subject--Solar Collectors/Antimatter
       Re: Request For Discussion: sci.space.moderated
             Re: Building Infrastructure
                Re: lifeboats
             Re: Laser launchers
         Re: Fred cut, AXAF and SIRTF funded
       British/Soviet Soyuz TM-12 docks with Mir space station
          Re: SPACE STATION FREEDOM WOUNDED
          Re: What comes after Fred's death?

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: 20 May 91 23:04:22 GMT
From: agate!spool.mu.edu!mips!zaphod.mps.ohio-state.edu!swrinde!elroy.jpl.nasa.gov!jpl-devvax![e-mail]  (Douglas Creel)
Subject: Re: NASA Headline News for 05/20/91 (Forwarded)

>>
>>This is NASA Headline News for Monday, May 20, 1991 . . .
>>
>>The crew of the STS-40 Space Shuttle Columbia arrived at Kennedy Space
>>Center yesterday afternoon to begin activities in preparation for
>>launch of their life science mission Wednesday morning.  Medical exams
>>and flight equipment fit checks dominate their schedule today.  STS- 40
>>Commander Bryan D. O'Connor and Pilot Sidney M. Gutierrez will log time
>>in the Shuttle Training Aircraft today, in preparation for the launch.
>>
>>                   * * * * * * * * * * * * * * * *
>>
>>NASA announced today that a second Astro mission will fly aboard the
>>Space Shuttle.  Cited as reason for the reflight was the success of the
>>first mission and the demonstrated ability of the instruments to
>>acquire high-quality scientific data.  The Astro mission will fly the
>>Hopkins Ultraviolet Telescope, the Ultraviolet Imaging Telescope and
>>the Wisconsin Ultraviolet Photopolarimeter Experiment.
>>

Here are two examples of how good science and manned spaceflight are not
mutually exclusive. Neither of these two science missions could have
been accomplished using unmanned spacecraft.

Douglas D. Creel
Navigation Systems Section (Mars Observer Project)
Jet Propulsion Laboratory

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

Date: 18 May 91 23:30:28 GMT
From: swrinde!cs.utexas.edu!news-server.csri.toronto.edu!utzoo![e-mail]  (Henry Spencer)
Subject: Re: space news from March 18 AW&ST

In article <[e-mail]> [e-mail] (William Lewis) writes:
>>offers a high enough exhaust velocity to make fast trajectories possible,
>                                               ^^^^^^^^^^^^^^^^^
>   What does a "fast trajectory" mean? Faster than a Hohmann orbit?

Yes, plus more amenable to short overall missions.  Using Hohmann orbits
for Earth-Mars-Earth is awkward because there is a *long* wait at Mars
for the return window.  Faster trajectories not only take less time
themselves, they give you more flexibility in planning the stay time.
--
And the bean-counter replied,           | Henry Spencer @ U of Toronto Zoology
"beans are more important".             |  [e-mail]  utzoo!henry

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

Date: 18 May 91 22:03:59 GMT
From: haven.umd.edu!socrates.umd.edu!socrates![e-mail]  (Raul Rockwell)
Subject: Re: SPACE STATION FREEDOM WOUNDED

Nick Szabo:
   >We've never tried a totally non-government approach, actually, so
   >it is hard to say how it would turn out.

Allen W. Sherzer:
   No large infrastructure project has ever been done without major
   government involvement.

This is necessary for government survival, witness J.P. Morgan and
anti-trust laws.  Thus the "lack of leadership" arguments used for
space funding.

Unfortunately, the US government has been working rather hard at
cutting its own throat.  (Witness the economics of welfare, taxation,
the budget deficit, etc., for instance.)  A self-destructing
government is at best a zero-sum game.

While I hesitate to recommend a solution, I think it is important to
realize that government actions are part of the environment, not
part of the solution.

And no, the government is not part of the problem either.  The problem
is getting mankind out into space.

Raul Rockwell

Disclaimer: not associated with Rockwell International :-)

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

Date: 19 May 91 04:22:17 GMT
From: valid!caber![e-mail]  (Louis K. Scheffer)
Subject: Re: New Subject--Solar Collectors/Antimatter

[e-mail] (Mark Gellis) writes:
>   1) Given a solar cell that will produce 10 kilowatts in Earth orbit,
>would the same cell (i.e., the same mass of finished product) produce more
>power if it was moved to Venus orbit, where it would be getting more than
>twice as much energy from sunlight?  (If power is the wrong word, I
>apologize; you know what I mean, though.)  Will it produce 20+ kilowatts
>now?  Do the cells have a limit on how much electricity they will produce,
>or will they just keep giving you more power if you increase the solar
>energy per square meter?

Yes, it will produce more power.  The current output is basically linear
with intensity, but the total power out is limited
by parasitics.  Solar cells designed for concentrated sunlight will work fine
up to at least 100 times normal intensity, *if you can keep them cool*. If they
get hot the voltage goes down.  Since power = voltage*current, it is important
to keep them cool.

>   2) If you can get more energy from solar cells by moving them closer
>to a star, what is the limit?  First, is there a point where the cells
>simply will not put out more energy, no matter how much sunlight they get.
>Also, there is obviously a point where the cells will melt, but where is
>that?  Could we build solar power stations, say, in Mercury orbit, where
>we would be getting more than six times the sunlight we get in Earth orbit?

See above.  The voltage output goes down as they get warmer, so simply moving
them closer to the sun will eventually reach the point of diminishing
returns.  If they are designed for it, however, you should be able to get
much closer to the sun than earth orbit.

-Lou Scheffer

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

Date: 19 May 91 21:00:55 GMT
From: phoenix![e-mail]  (Michael Woodhams)
Subject: Re: Request For Discussion: sci.space.moderated

In article <[e-mail]> [e-mail] (Phil Fraering) writes:
>It seems that at present most of the traffic of sci.space consists
>of an endless repetition of the same articles. I'm convinced that
[stuff omitted]
>it is posted. Occasionally I have seen one or two new ideas on
>sci.space...

I agree entirely. I have seriously considered unsubscribing, but
occasionally there is really good stuff from people in the know (such
as the loss of communications with Magellan) which I don't want to
miss. So I wade through endless garbage looking for it.

Mary Shafer (Message-ID: <[e-mail]>)
 writes
#everywhere.  (It's also true that the people whose postings are most
#interesting in sci.space, like Henry, are interesting everywhere.)

You are such a person yourself, and your posts are one of the things
that has kept me subscribed to this group. It's good to see you also
in soc.culture.new-zealand/australia.

>I would like to suggest that the position of moderator be rotated;
[...]
>BTW, am I doing this right? I think I posted to the necessary groups...
>
>Phil Fraering || Usenet (?):[e-mail] || YellNet: 318/365-5418

It is unclear to me whether you are suggesting that a new group called
sci.space.moderated be created, or whether the current sci.space have
a moderator imposed on it. Please clarify. I feel that two groups
should exist - s.s as it is now for the argumentative and masochists,
and s.s.m for me and All Right Thinking People (TM). A lot more
thought needs to be put into the charter for the group, however. On
what criterion is the moderator to select submissions? Should they add
editorial comment? If both s.s and s.s.m exist, should the stuff from
s.s.m automatically go to s.s also?

I suggest that the moderator accept submissions that
(1) contain new factual information regarding space science and
technology.

(2) add substantial new ideas to an existing discussion, from people
with experience in the field or with supporting references.

(Anyone suggest more criteria?)

After a discussion has run for about half a dozen postings, the
moderator should close the discussion direct people to continue it on
s.s (if the two group model is accepted.)

Certain people (such as the people who post JPL and NASA press
releases) could be given direct access to post, so that these articles
are not held up waiting for the moderator.

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

Date: 20 May 91 04:30:06 GMT
From: agate!lightning.Berkeley.EDU![e-mail]  (Frank Crary)
Subject: Re: Building Infrastructure

In article <[e-mail]> [e-mail] writes:
>>No large infrastructure project has ever been done without major
>>government involvement.
>
>Where did the thousands of billions of dollars worth -- over 1,000
>times more $$$ than available to NASA -- of oil rigs, oil pipelines,
>communications satellites, auto factories, steel factories, IC fabs,
>railroads, ocean-going ships, airplanes, skyscrapers, shopping malls,
>apartment buildings, power plants, etc. etc. etc. on this planet come
>from?
>
I cannot speak for all of these, but as I recall the government was
involved with the development of communications satellites, railroads
airplanes (e.g. airlines and air traffic control) and power plants
(nuclear one anyway).

>>This is the approach we need to take. If we want to reduce launch
>>costs, let's gurantee a large market at 75% of current prices and
>>reduce that price periodically. We need to take similar steps for
>>other industry as well.
>
>Fine, but don't dictate the size of rocket or satellite, the "best"
>or "paradigmatic" orbits, or the best payloads to launch.  These
>decisions best made by the industries serving the marketplace.
>
As I understood Allen Sherzer's post, "guarantee a market" means just
that: That the government will buy payloads launched to orbit. As such,
the government should have some say in what it will be buying. The
governemt would NOT just pay a company because they put up a satellite
for Intelsat. The payloads should be what the government needs, in the
orbits they need them, say in support of a major program (Lunar base?)

                                           Frank Crary
                       UC Berkeley

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

Date: 20 May 91 18:45:28 GMT
From: agate!tornado.Berkeley.EDU![e-mail]  (George William Herbert)
Subject: Re: lifeboats

In article <[e-mail]> [e-mail] (Henry Spencer) writes:
>>I don't think the command module alone could serve as a crew transport. Such
>>a transport would require at least 48 hours of autonomus power and life
>>[...]
>Adding power and life support should be a simple matter of another battery
>or two and another tank or two.  The CM had plenty of equipment that would
>[..]

Yes, were that the only problem...

>The one SM function that would have to be provided by new hardware would
>be retrofire.  The obvious method is a set of small solid motors a la Gemini.

You're forgetting something... all the orbital maneuvering (reaction control
system etc) was on the SM if I remember correctly.  I'm not sure how happy the
astronauts would be about dropping hydrazine in their capsule for RCS
purposes.  (You could use another propellant, but none of them that have
acceptable ( > 100 ) Isp are safe in an inhabited volume...


  == George William Herbert ==   *   JOAT = Jack Of All Trades = Generalist   *
 == JOAT for Hire: Anything, ==  #########  I do Naval Architecture, ##########
===+++ Anywhere, my price +++=== # Spacecraft Design, UNIX Systems Consulting #
 ==   [e-mail]   ==  # RPG writing/development, and lots of other #
  ==   [e-mail]   ==   ## random stuff, of course.  I'm a JOAT 8-) ##

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

Date: 19 May 91 12:54:34 GMT
From: swrinde!zaphod.mps.ohio-state.edu!sol.ctr.columbia.edu!emory!wa4mei!ke4zv![e-mail]  (Gary Coffman)
Subject: Re: Laser launchers


By now it has become clear to me that I was drawing conclusions from false
assumptions, made math errors, and was just generally stupid in a couple of
places. Thanks to everyone for setting me straight. I hope a few people
besides me learned something in the process so that the bandwidth wasn't
totally wasted.

To those that sent Email, thanks for all the numbers and explanations.
To those who sent death threats, I know who you are. :-)

Gary

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

Date: 20 May 91 21:57:30 GMT
From: swrinde!elroy.jpl.nasa.gov!jpl-devvax![e-mail]  (Douglas Creel)
Subject: Re: Fred cut, AXAF and SIRTF funded

>>That is _exactly_ what Congress did: it cut all funding for Fred,
>>and gave full funding to SIRTF and AXAF.

Not exactly. Actually the House Appropriations Committee submitted a budget for
negotiation in conference with the Senate which included almost all funds
requested for the station. The HUD, VA, and Independent Agencies committee was
the one which voted to cancel funding for Space Station Freedom. This vote also
happens to be non-binding, although it is used as reference by the appropriation
committee. The vote which was taken by a small part of the whole House doesn't
necessarily reflect the opinions of the rest of the House which still has to
vote on it and will probably debate the budget up until August. Plus which,
neither the President nor NASA administrator Truly support this move, so if you
think this is actually going to remain this way, I think you're just plain
dreaming.

Douglas D. Creel
Navigation Systems Section (Mars Observer Project)
Jet Propulsion Laboratory

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

From: [e-mail]
Date: 20 May 91 17:34 -0700
To: [e-mail], [e-mail],
        [e-mail], [e-mail],
        [e-mail], [e-mail],
        [e-mail]
Subject: British/Soviet Soyuz TM-12 docks with Mir space station

    The Soviet/British Juno flight on Soyuz TM-12 successfully docked with
the Mir space station on today (May 20th ) at about 17:25 Moscow Time (6:25
PDT).  On board were cosmonauts Anatoli Artsebarski and Sergei Krikalev,
plus Helen Sharman, the first British astronaut.  This mission was delayed
from its original launch date of May 12th.  They were greated by
Viktor Afanasyev and Musa Manarov, who were launched on Soyuz TM-11 on
Dec. 2 '90.  Afanasyev and Manarov will be bringing Sharman down on May 26th.
Artsebarski and Krikalev will be staying on board Mir for the next 6 months.
They will be doing several space walks, including one to repair the antenna
damage that caused the Progress M-7 to have problems docking at the
March 19th attempt.   In addition Radio Moscow stated the two would be
installing a new solar panel set to be delivered by their space shuttle.
    Sharman, who used to work as a chemist for a candy company, is called
in the British press, as the woman from Mars (her former employer).  There
was also considerable comment about the fact that Britain was the 23 nation
to have a person go into orbit, rather sad considering its considerable
contributions to the space field.
    Net problems at this end have kept me from posting since February.
Actually, I could not post about the launch as I was at a conference in
Europe at that time, but did get to see the British press coverage of it.
Sorry for not being able to cover things up to this date.  Hopefully I
will be back on the net full time now.

                            Glenn Chapman
                            Simon Fraser U.
                                                        Burnaby, B.C., Canada
                            [e-mail]

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

Date: 20 May 91 16:42:50 GMT
From: super![e-mail]  (Ronald G Minnich)
Subject: Re: SPACE STATION FREEDOM WOUNDED

In article <[e-mail]> [e-mail] (Brian Yamauchi) writes:
>My question is how much of this money will actually go to space
>science and unmanned space exploration.  I'd rather have a lot of
>Mariner Mark IIs, planetary rovers, and microprobes than Freedom, but
>I'd rather have Freedom than nothing...

Zip. Zero. Zed.
Leo Panetta, a fairly important person in this process, had an article
in the Wash. Post. In his view, NASA's budget is traded off against
education. I.e., they cut NASA, then fund schools. With that kind of
thinking, you can assume that money is GONE.
ron
p.s. Note I said 'important', not 'intelligent'. Once people figure
     out they can vote for bread and circuses, etc.

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

Date: 21 May 91 00:44:34 GMT
From: hub.ucsb.edu!ucsbuxa![e-mail]  (Charles Frank Radley)
Subject: Re: What comes after Fred's death?



Keeping the shuttle up longer than 30 days is not very
practical.  Already payload mass must be sacrificed to achieve
the 30 day capability.
   There are other limitations in Shuttle ( not sure what ) which
prevent it staying up much longer.
  Freedom was baselined for 90 day mission crew rotation.

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

End of SPACE Digest V13 #598
*******************