Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT/SPACEDIG/V13_5/V13_554.TXT

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Subject: SPACE Digest V13 #554

SPACE Digest                                     Volume 13 : Issue 554

Today's Topics:
            SPACE Digest V13 #534
             Re: Shuttle launches
            Pegasus/SMEX - Alive and Well
      Re: 14 Astronauts have died for space exploration?
              Re: Why the space station?
       Re: Laser launchers (really microwave launchers)
           Re: Advancing Launch Technology

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Resent-Date:  Mon, 13 May 91 22:14:05 EDT
Resent-From: Tom McWilliams <[e-mail]>
Resent-To: [e-mail]
Date:         Mon, 13 May 91 01:41:01 EDT
Reply-To: [e-mail]
From: [e-mail]
Subject:      SPACE Digest V13 #534
Comments: To: [e-mail]
To: david polito <[e-mail]>, Tom McWilliams <[e-mail]>

Subject: Re: Ethics of Terraforming (was Re: Terraforming Venus)

>>I myself note that it took us over 3 million years to climb out of our
>>gravity well. I wonder why anybody would want to climb back down another
>>one? For this reason I don't think teraforming is a good idea.
>>

>        Perhaps some people *like* living at the bottom of a gravity well.

>        There are perceived advantages to planet sized habitats. We
>know, for example, that at least one such life support system has
>continued to provide LSU service for over three billion years with
>minimal maintainance (Although the turnover in resident species has been
>fairly high); we *don't* know that the tin-can habitats can match that
>record. Is it more efficient to creat a life support system that, while
>using most of the mass involved to merely generate gravity to contain
>the biosphere, persists for billions of years, or is it better to build
>myriads of small habitats, whose peak population might be higher, but
>whose lifespans might be much lower?

Interesting question.  It might be illustrative to consider some other
examples of biological systems

If we could build lots of little habitats, we would without a doubt start
filling known space with them.  It would probably be not long before other
star systems started filling up.  Invoke your favorite SF story here.

Now, though the lifespans of each colony would be tiny compared to the life-
span of the planet, the lifespan of the planet would be tiny compared
to the lifespan of the civilization (since we would no longer be doomed by
the Sun's imminent Red-giant expansion)

For 'colonies' substitute "cell", for 'planet' substitute "body", and for
'civilization' substitute "species".  Substitute 'old age' for 'Sun's
death' and the analogy with another aspect of biology is complete.

Similarly, though the colony is much more fragile than a planet, there are
so many of them that it makes up for their fragileness.

A good analogy here would be the MayFly season in Detroit (Cars skid on their
dead bodies in the street.  Like snow in June.  Disgusting.)  Though millions
die because of the inability of their weak little bodies to compete with a
harsh world, they come back every year, to the chagrin of the populace and the
joy of the birds.

But alas, the Earth too is fragile!
Though the Earth is killable with the power we command  (as well as it's
unfortunate placement in a solar system full of Asteroids), it is doubtful
if any one act of Nature or Man could kill everyone, if there were colonies
at all inclinations and distances from the Sun.

This could apply not only to military action (which would be inevitable in the
     rich-resource era that would inevitably follow any large-scale space
     industial development)
But also pollution, disease, social strife, cultural decay, bad music, etc.
would no longer be powerful enough to destroy civilization.

Having a few planets would not gain this advantage the way a few thousand
colonies would.

And if there was some sort of military action, what would stop those in the
colonies from using Earth's gravity well to propel missiles (rocks) on their
enemies?  We just bombed the piss out of the 'cradle of civilization' for
Saddam.  We'd do it again.  So what if it's earth?  The Greeks believed that
the Children vanquish the Parents.  We're doing it now, and we don't have
any place to go after it's wrecked.  Being born on a colony, you'd care less
about the planet.

Just my imagination going full speed. sorry.
Tommy Mac
Acknowledge-To: <18084TM@MSU>

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

Date: 13 May 91 16:32:04 GMT
From: cis.ohio-state.edu!zaphod.mps.ohio-state.edu!rpi!news-server.csri.toronto.edu!utzoo![e-mail]  (Henry Spencer)
Subject: Re: Shuttle launches

In article <[e-mail]> [e-mail] (DAVID F ROBINSON) writes:
>Was there ever any consideration for launching the shuttle off of the carrier
>aircraft...

There is no aircraft on Earth that could carry a fueled shuttle stack.  The
orbiter, with no fuel at all on board, is a full load for a 747.

People have proposed rather smaller shuttle analogs launched from 747-back.
Nobody has yet funded one.
--
And the bean-counter replied,           | Henry Spencer @ U of Toronto Zoology
"beans are more important".             |  [e-mail]  utzoo!henry

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

Date: 13 May 91 17:41:03 GMT
From: dftsrv![e-mail]  (Dick Palace)
Subject: Pegasus/SMEX - Alive and Well

There has been some interest in Small Explorers (SMEX) and a lot
of interest in Pegasus. The SMEX program was to have used the Scout
Launch Vehicle, and indeed the first SMEX called SAMPEX for (Solar
Anomalous and Magnetospheric Particle Explorer) will be launched
from the WTR (Western Test Range) in June of 1992. The next two
Small Explorers will be launched aboard the Pegasus Vehicle. The
Special Payloads Division here at the Goddard Space Flight Center
(GSFC) will have the responsability of supplying the data handling and
attitude control hardware and electronics plus integrating and testing
the payload to the above mentioned subsystems.

I'll give you what information that I have on the next two SMEX
launches.

--------------------------------------------------------------------------
                           FAST

Fast Auroral Snapshot Explorer

Principal Investigator: C.W. Carlson, University of California at
                                      Berkeley

Instruments:
     EESA - Quadrispherical Electrostatic Electron Analyzer.
        University of California at Berkeley
     TEAMS - Time-of-Flight Energy Angle Mass Spectrograph. University
        of New Hampshire, Lockheed-Palo Alto.
     EFPE - Electric Field Plasma Experiment. University of California
        at Berkeley
     Magnetometer. University of California at Los Angeles

Planned delivery to GSFC:  January 1994

Launch: September 1994 - Wallops Flight Facility

Vehicle: Pegasus

Lifetime: 1 Year

Orbit: 350X4200 KM Altitude, 83 Deg. Inclination

----------------------------------------------------------------------------
                           SWAS

Submillimeter Wave Astronomy Satellite

Principal Investigator: G.J. Melnick, Smithsonian Astrophysical
                        observatory (SAO)

Instrument:
     Telescope - Ball Aerospace Systems Group
     Submillimeter Receiver System - Millitech Corporation
     AOS - Acousto-optical Spectrometer. University of Cologne, West
                                         Germany

Planned delivery to GSFC: June 1, 1994

Launch Date: June 1995

Vehicle: Pegasus

Launch Site: Wallops Flight Facility

Lifetime: 3 Years

Orbit: 500-600 Circular, 38Deg. Inclination

Weight: 123.3 Lbs. Instrument

Telemetry: 12 KBPS Continuous, 130 MBYTES per day.


For those who want to know about SAMPEX I'll include it.


--------------------------------------------------------------------------
                         SAMPEX

Solar Anomalous and Magnetospheric Particle Explorer

Principal Investigator: G.M. Mason, University of Maryland

Instruments:

      Leica - Low Energy Ion Composition Analyzer. University of
                                                  Maryland
      HILT - Heavy Ion Large Telescope. Max-Planck Institute,
                                        Garching, West Germany
      MAST/PET - Mass Spectrometer Telescope/Proton-Electron Telescope
                 California Institute of Technology/GSFC
      DPU - Data Processing Unit. Aerospace Corporation

Delivery to GSFC: August 1991

Launch Site: Western Test Range

Launch Date: June 1992

Vehicle: Scout

Lifetime: 3 year goal

Orbit: 560X700 Km Altitude Circular, 82 Deg. Inclination - not sun
       Synchronous.

Instrument Weight: 90 Lbs.

There you have it, all I know at this time. Please! Please! don't flood
me with E-Mail for other details. What I gave is what I know. If and
when I get updates I will pass them along. General questions on
Goddard, or the Special Payloads Division, I would most happily answer
it I can.

Dick


I an not responsible for typos, even if I made them 8-)


--
Dick Palace         Goddard Space Flight Center      [phone]

[e-mail]

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

Date: 13 May 91 18:56:41 GMT
From: pioneer.arc.nasa.gov![e-mail]  (Mary Shafer -- OFDD)
Subject: Re: 14 Astronauts have died for space exploration?

In article <Added.sc=[e-mail]> [e-mail] (Bob Rehak Ext. 3-9437, AIS Central Services  -  Swen Parson 146) writes:

[In reference to the Astronaut Memorial]

>14 astronauts?  Last time I counted there were only 10.

>Apollo I: Grissom, White, and Chaffee.
>STS-61L Challenger: Scobee, Smith, Resnik, Onizuka, McNair,
>                    Jarvis, and McAuliffe.

>A couple have did flight testing aircraft that was not related to
>space exploration and a couple have did in car accidents...I think.

There are 17 deceased US astronauts.  This number from the JSC PAO
Library last week.

Elliot See and another died in the McAir parking lot when their T-38
clipped the corner of the building in the fog.  Sunny Carter died in
a commuter airline crash (with John Tower).  One of the Navy guys
died in a airplane crash (maybe doing aerobatics?)  One of the really
early guys (Mitchell?) died of a heart attack.

172 astronauts total, 88 current, 67 retired or reassigned, 17 deceased.
There are also 23 astronaut candidates.

--
Mary Shafer  [e-mail]  ames!skipper.dfrf.nasa.gov!shafer
           NASA Ames Dryden Flight Research Facility, Edwards, CA
                     Of course I don't speak for NASA
            "Turn to kill, not to engage."  CDR Willie Driscoll

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

Date: 13 May 91 21:29:13 GMT
From: pasteur!dog.ee.lbl.gov!hellgate.utah.edu!cs.utexas.edu!usc!zaphod.mps.ohio-state.edu!rpi!news-server.csri.toronto.edu!utzoo![e-mail]  (Henry Spencer)
Subject: Re: Why the space station?

In article <[e-mail]> [e-mail] writes:
>>The smaller probes definitely don't need assembly.  The bigger ones really
>>could use it.  Just look at some of the elaborate schemes people have put
>>together trying to do a Mars sample return ...
>
>Care to expand on this?  I fail to see how in-orbit assembly makes
>a sample return, from Mars or other places, any easier.

It makes a bigger vehicle possible, because you can add an upper stage
launched separately.  The studies I've seen have all concluded that doing
a Mars sample return -- at least, the sort of sample return the Mars people
would like, bearing in mind that they'll probably only get one of them --
with one Titan-IV-Centaur payload is just not practical.  Which means
playing elaborate games of one kind or another to split it up.

>Note that both the Soviet Union and the U.S. did extensive sample
>return from the Moon without in-orbit assembly.

The US did it using a heavy booster which is no longer available.  The
Soviets used a Titan-class booster and got a bare-minimum sample return
with no frills, from an airless planet with half as much gravity that is
close enough to make navigation much easier and avoid a long cruise phase.
--
And the bean-counter replied,           | Henry Spencer @ U of Toronto Zoology
"beans are more important".             |  [e-mail]  utzoo!henry

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

Date: 14 May 91 16:47:07 GMT
From: dog.ee.lbl.gov!hellgate.utah.edu!caen!zaphod.mps.ohio-state.edu!rpi!news-server.csri.toronto.edu!utzoo![e-mail]  (Henry Spencer)
Subject: Re: Laser launchers (really microwave launchers)

In article <[e-mail]> [e-mail] (Thomas Johnsson) writes:
>I wonder if anyone has considered beaming the power to the launch
>vehicle using microwaves instead of a laser...

If you want to deliver it as electrical energy, microwaves are superior.
But the longer wavelength makes them much harder to beam tightly, and also
makes it awkward to arrange for them to be absorbed in a thin layer of
reaction mass (which is what laser launchers do).  Beaming power to run
electric rockets of one kind or another (e.g. ion rockets) has potential,
but the low thrust limits its usefulness for Earth-to-orbit launch.  The
laser launcher looks better for that.

Doubtless Gary Coffman is going to reiterate at length why laser launchers
are silly and won't work.  Sorry, Gary, given a choice of believing you or
believing people like Arthur Kantrowitz and Jordin Kare (head of the LLNL
laser-launcher group), you lose.  Look up that conference proceedings I
referenced a little while ago if you want to find out why laser launchers
will work.
--
And the bean-counter replied,           | Henry Spencer @ U of Toronto Zoology
"beans are more important".             |  [e-mail]  utzoo!henry

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

Date: 14 May 91 18:05:13 GMT
From: prism![e-mail]  (Matthew DeLuca)
Subject: Re: Advancing Launch Technology

In article <[e-mail]> [e-mail] (Fraering Philip) writes:
[replying to Gary Coffman]

>1. Assembly in space may be a lot cheaper and easier than you think.
>Since the Russians can do it with their rather less developed automation,
>shouldn't it be easier with the more developed technology here?

The Russians haven't actually done any assembly in space of the nature that
is being talked about.  What they *have* done is dock lots of capsules
together, which isn't particularly more sophisticated than what we and they
have been doing for the last twenty-five years.

>2. Currently it looks like it is the small booster which can take
>business away from the larger one in spite of a cost per pound
>imbalance in favor of the larger booster. My example, again, is
>Pegasus...

Cost-per-pound is frequently a fallacy.  The important number to look at
is how much it costs to get your payload into orbit.  If I have a fifty
pound payload to put up, and I put it on a bare-bones $5 million rocket,
I am paying $100,000 per pound.  If it's worth the $5 million I paid, though,
then I got a good deal.

In my opinion, this is why there is going to be a solid market for the
small booster; universities and private companies can afford the few
millions of dollars a small rocket must cost to do some basic research,
whereas they cannot begin to afford the fifty-million dollar costs of the
current rockets we are using.
--
Matthew DeLuca
Georgia Institute of Technology      "I'd hire the Dorsai, if I knew their
Office of Information Technology      P.O. box."  - Zebadiah Carter,
Internet: [e-mail]    _The Number of the Beast_

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

End of SPACE Digest V13 #554
*******************