Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT/SPACEDIG/V13_5/V13_556.TXT

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Subject: SPACE Digest V13 #556

SPACE Digest                                     Volume 13 : Issue 556

Today's Topics:
      Re: 14 Astronauts have died for space exploration?
         Progress? (was: Re: Ethics of Terraforming)
              Re: Honking at cyclists...
             Re: R-100 and R-101
      Re: 14 Astronauts have died for space exploration?
              Re: SPACE Digest V13 #516
        Re: Tethers (was Re: Laser launchers)
           Re: Advancing Launch Technology
           New Subject--Solar Collectors/Antimatter
               Re: Saturn V and the ALS

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: 15 May 91 01:33:20 GMT
From: agate!lightning.Berkeley.EDU![e-mail]  (Frank Crary)
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:
>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.

The remaining four are Soviet Kosmonauts:

Soyuz 1: 23 April 1967: Vladimir M. Komarov
Soyuz 11:29 June  1971: Viktor I. Patsayev
            Georgi T. Dobrovolsky
            Vladislav N. Volkov


All rumors to the contrary, there is NO evidence of farther Soviet space
fatalities.

                     Frank Crary
                     UC Berkeley

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

Date: Tue, 14 May 91 08:42:57 PDT
From: [e-mail]
X-Vmsmail-To: UTADNX::UTSPAN::AMES::"[e-mail]"
Subject: Progress? (was: Re: Ethics of Terraforming)


In SPACE Digest V13 #545,
VAX1.CC.UAKRON.EDU!mcs.kent.edu!usenet.ins.cwru.edu!agate!lightning.
 Berkeley.EDU![e-mail]  (Frank Crary) writes:

>In article <[e-mail]> [e-mail] (will) writes:
>...
>>    Also, if there was life before, and it was lost, it should be discovered
>>    and studied.  A lot must be done before we go and wipe out a planet just
>>    for our own use.  Seems very selfish to me.
>It may very well be selfish. However I am an avowed racist: I am strongly
>biased in favor of the human race. If the growth and welfare of the
>human race requires the loss of fosilized Martian pond scum, or even
>now living micro organisims, I say the Martians loose.
>
>                    Frank Crary
>                    UC Berkeley

Talk about being a slave to your genes!  It's just this sort of "damn
everything but humans" attitude that has wrought so much havoc to date.
I used to be pretty gung ho about humans expanding into space, but a few
years of reading SPACE Digest has cured me of that.  How sad it would be
if the net result of ten billion years of preparation plus five billion
years of evolution was to spread MacDonald's to the far corners of the
universe.

_____________
Dale M. Greer, whose opinions are not to be confused with those of the
Center for Space Sciences, U.T. at Dallas, UTSPAN::UTADNX::UTDSSA::GREER
"A tree's a tree.  How many more do you need to look at?" - Ronald Reagan

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

Date: 14 May 91 23:10:00 GMT
From: snorkelwacker.mit.edu!think.com!spool.mu.edu!news.nd.edu!mentor.cc.purdue.edu![e-mail]  (Mark Gellis)
Subject: Re: Honking at cyclists...


Regarding the growth of humans into space, may I recommend a volume
called INTERSTELLAR MIGRATION AND THE HUMAN EXPERIENCE, edited by Finney
and Jones, and especially the article by David Criswell on space
industrialization.  Criswell makes some interesting claims, suggesting
that humanity should eventually dismantle the sun, converting it into a
smaller and longer-lived star and using the nearly two octillion tons of
hydrogen, helium, and other elements gleaned by "sun-lifting" to build
and power habitats.  He estimates we could have 80 quadrillion people
living in the solar system, each person having millions of tons of raw
materials at their beck and call.  Interesting stuff.

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

Date: 14 May 91 13:37:37 GMT
From: eru!hagbard!sunic!mcsun!ukc!acorn!ixi![e-mail]  (Clive Feather)
Subject: Re: R-100 and R-101

In article <[e-mail]> [e-mail] (Henry Spencer) writes:
>The R-101 had grave trouble flying at all, needed hasty and ill-advised
>lengthening to have any hope of meeting its performance specs, and was
>generally over budget, behind schedule, and below expectations... and on
>its maiden voyage to India, this flagship of socialist progress crashed
>on a hillside in France with no survivors.

There are several ex-R101 crew members who would be surprised to hear
that. I can provide names if you want. I think that some of them might
still be alive.
--
Clive D.W. Feather     | IXI Limited         | If you lie to the compiler,
[e-mail]          | 62-74 Burleigh St.  | it will get its revenge.
Phone: [phone] | Cambridge   CB1 1OJ |   - Henry Spencer
(USA: 1 800 XDESK 57)  | United Kingdom      |

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

Date: 15 May 91 00:00:07 GMT
From: cis.ohio-state.edu!zaphod.mps.ohio-state.edu!samsung!news.cs.indiana.edu!ux1.cso.uiuc.edu!m.cs.uiuc.edu!ibma0.cs.uiuc.edu!sunc1.cs.uiuc.edu![e-mail]  (Roger Noe)
Subject: Re: 14 Astronauts have died for space exploration?

In article <[e-mail]> [e-mail] writes:
>The May 13 Newsweek has an article on the memorial.  They say that
>the fourteen are the three Apollo I astronauts, the seven Challenger
>astrounauts and Charles A. Bassett II, Theodore C. Freeman, Elliot M. See Jr.,
>and Clifton C. Williams Jr. who all died in airplane crashes.

Make it 15.  I think it has already been announced that "Sonny"
Carter's name will be added to the memorial shortly.
--
Roger Noe                            [e-mail]
Department of Computer Science       [e-mail]
University of Illinois               40:06:39 N.  88:13:41 W.
Urbana, IL  61801  USA

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

Date: 15 May 91 04:07:44 GMT
From: cis.ohio-state.edu!zaphod.mps.ohio-state.edu!uakari.primate.wisc.edu!sdd.hp.com!spool.mu.edu!uwm.edu!ogicse!sequent!muncher.sequent.com![e-mail]
Subject: Re: SPACE Digest V13 #516

In article <[e-mail]> [e-mail] (Matthew DeLuca) writes:

>How does any of what you said apply to Galileo?

Never said it did; my apologies for not being clearer on that point.
I agree with you, Galileo is built for Jupiter and its moons and
should go there if at all possible (while flying by asteroids on the
way if possible).  I was answering your comment about exploration's
ability to change timetables.  The discovery of small asteroids and
comets via infrared telescope would radically shrink the expense, and
therefore the timetable, of capture missions.  Solving several
outstanding problems relating to earth-crossing resources, including the
distribution of water, the existence of nickel-iron regolith, and the
source of ureleite diamonds could also create the motivation to invest
in mining.

For that matter, the discovery of ore-forming processes on Io's heavily
differentiated, sulfide-rich surface could also shorten timetables.
(Although, mining that would be one heck of a challenge. :-)
Sulfides and differentiation are the primary drivers for ore-forming
processes on Earth, but they exist to a much greater degree on Io.

In any case, if they get the antenna unstuck it will be a very happy
day.


>However, my
>point was that diverting Galileo from its mission will have absolutely
>no effect on the rate of our advancement towards this level of space
>exploitation,

Well, _probably_ not.  With exploration, never say never.  But
infrared telescope satellites, asteroid sampling in Antartica, visual
searches, and more specialized flyby and sampling probes would be superior
to extra Galileo flybies.


--
Nick Szabo                [e-mail]
"If you understand something the first time you see it, you probably
knew it already.  The more bewildered you are, the more successful
the mission was." -- Ed Stone, Voyager space explorer

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

Date: 14 May 91 18:07:49 GMT
From: sdd.hp.com!cs.utexas.edu!news-server.csri.toronto.edu!helios.physics.utoronto.ca!aurora.physics.utoronto.ca![e-mail]  (Christopher Neufeld)
Subject: Re: Tethers (was Re: Laser launchers)

In article <[e-mail]> [e-mail] (Gary Coffman) writes:
>
>Let's look at a typical strawman tether launch. Let's propose a 1000 km
>tether whose center of mass is in a 700 km orbit. To hook on to the
>lower end of the tether, you need to be going faster than the orbital
>velocity of a 700 km orbit and be at an altitude of 200 km. If you've
>already gone that far, you've paid most of the cost to orbit.
>
   No, that's not right. If the tether is rotating, resembling the spoke
of an invisible wheel rolling around the surface of the Earth, then the
velocity of the tip drops to zero briefly. A person standing on the
ground would see the tether come in from a high angle, straightening out
until it was coming straight down, stop, then take off in the upward
direction and shoot away in a high angle along the ground path of the
tether. The payload could be attached from a hot air balloon if you
really thought it was necessary. The size of the tether establishes the
accelerations of the payloads. Note that the upper end of the tether is
going at twice orbital velocity, so it's above escape. The tether, then,
is taking a stationary object from the upper atmosphere, and delivering
it to interplanetary space without that object having to burn any fuel.
The tether can now take a week or a month to boost its orbit with high
Isp engines and be ready for the next payload.
   If you don't want to go out into interplanetary space you can just
let go of the tether a bit earlier, and bring along an apogee thruster
to circularize the orbit.

>So the
>tether doesn't buy you that much. And you've added considerable Rube
>Goldberg complication to the scheduling of your launch. Above an airless
>body like the Moon, a tether begins to make a lot of sense. But for
>Earth based launches, you've got to keep the end of the tether above
>the majority of air resistance or it'll end up in your lap.
>
   Clearly it can buy you quite a bit. You have to watch out for air
effects, but the tether is moving quite slowly relative to the ground
when it's in air. You might be able to get away with a tether which
drops down to a couple of dozen kilometres altitude without too much
trouble with air, and a cargo aircraft to that altitude costs
considerably less than a rocket which carries the same payload to Earth
escape, even when you figure in the fuel which the tether will need to
consume in order to maintain its orbit. If the air is thick enough to
bother a tether, it's probably thick enough to hold an airplane up, so
they should be able to mate nicely. The airplane doesn't have to be
going anywhere near orbital velocity.

>It always comes back to fighting that pesky air. That's why I keep
>harping on turning that liability into an asset by using wings and
>air breathing engines to get above most of it.
>
   That's exactly what you'd do with such a tether system. The tether
would represent a significant advantage in getting the payloads out,
though.

>Gary


--
 Christopher Neufeld....Just a graduate student  | Flash: morning star seen
 [e-mail]    Ad astra! | in evening! Baffled
 cneufeld@{pnet91,pro-cco}.cts.com               | astronomers: "could mean
 "Don't edit reality for the sake of simplicity" | second coming of Elvis!"

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

Date: 14 May 91 20:57:46 GMT
From: mintaka!think.com!zaphod.mps.ohio-state.edu!caen!ox.com!hela![e-mail]  (Allen W. Sherzer)
Subject: Re: Advancing Launch Technology

In article <[e-mail]> [e-mail] (Fraering Philip) writes:

>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...

This is not a flame but I think you missed the boat here. No payloads
have gone from the larger ones to the smaller ones. It therefore
cannot be said that they are loosing buisness.

What IS happening is that we are seeing a new market develop. This is
not taking buisness away but rather adding more buisness. In other
words, making the pie bigger.

  Allen

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

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

Date: 14 May 91 23:04:13 GMT
From: dog.ee.lbl.gov!hellgate.utah.edu!caen!sdd.hp.com!spool.mu.edu!news.nd.edu!mentor.cc.purdue.edu![e-mail]  (Mark Gellis)
Subject: New Subject--Solar Collectors/Antimatter


I have a question or two regarding possible future applications of solar
power.  Robert Forward suggests that it is possible to produce antimatter
with a reasonable degree of efficiency.  His design, however, calls for a
lot of power.  Now, since the use he suggests for antimatter is rocket
fuel (his argument, which I accept, is that it is so expensive that fusion
and solar are really much better for most other power requirements), it
makes sense to bring in other space-related technologies.  If you have a
space-based economy a few hundred years down the line, you need a LOT of
antimatter if you want people zipping around the solar system.  You
especially want antimatter if you start colonizing the cometary halo--
lots of organics out there, so people will probably go there eventually--
where the distances require you to have fairly fast spaceships.  (Fusion-
driven spacecraft will have cheaper fuel requirements since deuterium is
not particularly rare, but antimatter allows much greater velocities.)

My question regards the efficiency of solar collectors.  Now, obviously,
technology will change and improve during the next few centuries, but based
on what we know today about such solar power cells...

   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?

   (I ask this question because if you can do this, it is probably much
cheaper to produce a certain amount of solar cells and move them into a
close orbit around the sun, as opposed to building more and keeping them
where you build them.)

   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?

  (Obviously, it depends on the materials involved.  Also, clearly, solar
cells are getting better all the time, and we cannot predict what technology
will be like in the far future, but I would appreciate speculations based
on existing technology.)

  Thanks in advance.

  Mark Gellis
  [e-mail]

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

Date: 14 May 91 02:26:37 GMT
From: skipper![e-mail]  (Mary Shafer)
Subject: Re: Saturn V and the ALS

In article <[e-mail]> [e-mail] ("Allen W. Sherzer") writes:


   Fair enough. But please do read the article in the September 90 issue of
   Aerospace America. If for no other reason then you owe it to yourself to
   be as informed as you can be.

Well, as a 15-year member and an Associate Fellow of AIAA, married to
an AIAA Fellow with over 20 years of membership (including chairing
the AFM TC and it's conference), it's my opinion that Aerospace
America is not necessarily informational.

Study the list of authors some time.  You'll notice that none of them
have any technical qualifications.  Every now and then they'll let a
technical person write an article, but they then edit it into
incomprehensibility and don't give the technical person a chance to
review it.  For this reason, many people refuse to contribute to it
any more.

The various Journals, however, are still of high quality and definitely
worth reading.  (Even though I can't see how my paper is _ever_ going
to make the page limit!)

--
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

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

End of SPACE Digest V13 #556
*******************