Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT/SPACEDIG/V10_2/V10_246.TXT

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Subject: SPACE Digest V10 #246

SPACE Digest                                     Volume 10 : Issue 246

Today's Topics:
        Private Space Industries -- What's up?
         Population pressure to move to space
            Re: Moon Colonies / Ant Tanks
              More about a spacial lift
        Protein Crystals Grown in Space Prove Superior
         Re: Radiation exposure for Apollo astronauts
               Re: HST Resolving power
            Hubble Space Telescope
           Re: Population pressure to move to space
              Re: Space Elevator
              Re: Space Elevator
----------------------------------------------------------------------

Date: 13 Nov 89 22:39:55 GMT
From: cs.utexas.edu!halley![e-mail]  (David M VomLehn)
Subject: Private Space Industries -- What's up?

I've been wondering what's going on with Amroc since their recent launch failure
and haven't seen news on or off the net.  Are they going to try again?

And what about others, such as SSI of Houston?  I seem to remember that they
were working on something called the Conestoga.

Also, addresses for these and other companies would be useful.
--
David M. VomLehn                    work: [phone]
...utexas!halley!vomlehn                home: [phone]
Disclaimer:  These are my opinions and should not be construed as those of
my employeer, associates or anyone else.

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

Date: 13 Nov 89 15:31:42 GMT
From: cs.utexas.edu!samsung!aplcen!haven!umbc3!umbc5.umbc.edu![e-mail]  (Sang J. Moon)
Subject: Population pressure to move to space

It occurs to me that if the threat of major war is removed from earth via
peace between USA and USSR, the population explosion resulting from lack of
massive death will necessitate developing ways to put the surplus population
into space or else we will have to have another war.
-----------------------------------------------------------------------
    "I have faith in God, but I do not have faith in the Church."

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

Date: Mon, 13 Nov 89 20:26:22 EST
From: John Roberts <[e-mail]>
Disclaimer: Opinions expressed are those of the sender
    and do not reflect NIST policy or agreement.
Subject: Re: Moon Colonies / Ant Tanks


There is perhaps an interesting analogy to the issue of living on the moon
or elsewhere away from earth: the lifestyle of an Olympic athlete.

A US Olympic athlete goes through years of what I would consider sheer
torture, with little or no financial incentive, for the slim chance of
being able to participate in the Olympics. (Only a small fraction of those
who accomplish this goal make any money in advertising, etc.) I have never
been interested in trying to become an Olympic athlete, and hardly anyone
I know has attempted to do so. (I do know one Olympic athlete, and two
others who tried.) Nevertheless, I respect those who are interested in
competing, enjoy watching the competitions, and am pleased when a
competitor from my country (or occasionally someone from another country)
does particularly well. I do not mind supporting these activities to some
extent.

Similarly, while it is likely that most people would not enjoy the lifestyle
in an early extraterrestrial colony, there are probably a considerable
number of people who would choose it, and I do not feel that it is proper for
the majority to proclaim that this minority shouldn't go, on the grounds
that they "probably wouldn't like it". If some group of which I am a member
(humanity, the United States, or a group of private investors) succeeds in
establishing a colony, I will enjoy a feeling of accomplishment, and consider
the project as a worthwhile goal in itself, aside from any added capabilities
such an attainment might provide, even if I do not personally move to the
colony. I do not mind supporting this objective to a "reasonable" extent.

I agree that the first space colonies are likely to be uncomfortable. As I
have stated before, I believe that manned space activity should be supported
in balanced manner (mostly research on human habitation itself at this time),
such that it does not eclipse unmanned exploration, and earth-based space
science.

Now, somebody please post a counterargument that this analogy is not valid,
because Olympic athletes do not have to live underground, and Gatorade on
Earth is cheaper than Tang in space. :-)
                                          John Roberts
                                          [e-mail]

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

Date: 11/13/89 14:39:05
From: [e-mail]
Comment: CROSSNET mail via SMTP@INTERBIT
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Subject: More about a spacial lift

I just read that article in "Science" Vol.151 p.682 (11 Feb. 66) and
the following correspondence in Vol.158 p. 946 (17 Nov. 67) that
Christofer Neufeld cited in space digest v10 #236. Well, that
spacial lift seems to be an old idea indeed.

Now it seems that the material discussion is ten years old anyway:
carbon whiskers are not yet produced in bulk as far as I know, but
the modern idea is to paste the resistant part with some protective
matrix (ceramic for instance), so as to mix the advantages of
different materials into a single compound one.

Apart from the material point of view, the objections raised in this
article against such cable are 1) deleterious effects of ionosphere
and space environment (meteorites and satellite collision), 2) wind
and climate effects, and 3) stability problems:
  "...the reviewers were concerned about problems of stability and
   felt that these might make "sky hook" impraticable. The majority
   recommended that we accept this paper in spite of their
   reservations.- Editor."

Protection against ionosphere will probably require a special
coating, aluminium oxide or diamond for instance. This may be a
problem, for the coating increases the cable's total weight. But
since the coating mass varies proportionally with the cable's
diameter, the cable needs only to be thick enough. An uneven stress
distribution might be a concern if the cable's elasticity ecceeds
that of the coating, but that should not be the case since the cable
is the resistant part.

Micro-collisions might of course wear the cable, but larger ones
should be detected and destroyed in time. The target is quite large,
of course (some 100 km^2), but if we can't protect that, then the
whole space-war affair is a joke. Furthermore, there might be
several cables some kilometers apart, so that if one split the
others can take the extra load until the damaged one is repaired.
(And if a shuttle is on the cable at that moment, eject it and hope
that the parachutes will be strong enough.)  Anyway, it's a strong
incitation to stop littering space with such fragments.

For wind and climate effects, the cable would probably start from
some point near the equator, where climate is stable and weather
forecast easy. There might be some bad storms from time to time, but
once again, if the cable is thick enough it can withstand almost
anything. Furthermore, if the weather forecast is really bad, you
just need to pull up the cable for a while and anchor it back some
other day. If this happens only once every ten year, then it can be
worth the manoeuvre.

The mention of stability effect is certainly a joke. Tidal effect
can be computed years in advance, cummulative wind effects can be
evaluated days in advance. To counterbalance such effects, the
ground station and the geostationary one can push or pull the cable,
the loose end of the cable can be mooved as well, and various load
distributions and speeds can be used to tamper any undesired
harmonic (varying the speed adds the Coriolis effect).  Furthermore,
several cables anchored on different sides of the equator can be
used with eneven pulls to balance any lateral movement. Even taking
into account the propagation time of an impulse from end to end
along the cable (an hour or so if at 10 km/s), this is well under
the time scale of these unstability sources. How do you think
modern aircraft can fligh, being aerodynamically unstable? This
is just a matter of negative feedback automatically injected in
the system.

If the figures given in the "Science" article are correct, the mass
of a quartz cable capable of withstanding a 200km/h wind would be
200 tons. Is that heavy? It's just one fourth of the Effeil Tower...
If NASA can't put that much in orbit, I'm sure Ariane will...

Now my point was not only an Earth lift, but also a Moon one. That
one has several advantages. First of all, no wind, no storm, and no
Ionosphere. Second, Moon's gravity being only 1/6 of Earth's, and
its diameter being in the same proportion, a steel cable is enough
in that case. (Well, I think it is.)

This brings us to the interest in creating moon colonies. With such
a cable, the cost of bringing up material for large space structures
is cheap, as far as energy is concerned. Of course, mining on the
Moon is not simple, so that the cost of material produced over ther
will be astronautical with respect to Earth's standards, but that is
not the point: the real problem is the cost of such material once
transferred into orbit, and here moon materials are at an advantage.

Anything can be digged out of the Moon. In order to create a space
industry, it is useless to get any material from Earth once a Moon
base is built. Even transportation is cheap: just use the Moon
cable, then sail back to earth with solar wings. It might take some
time to bring such cargos, but who cares? there is no need to put a
crew into these. The only thing that cannot be found on the Moon is
a human supervisor: they will have to be sent to orbit the hard way,
as long as an Earth cable has not been installed.

As a matter of fact, I view the Moon base as a gateway to
large-scale space industry: first get raw or refined material on the
Moon, then process it in space, and finaly send it to Earth. If
space industry is useless, so will probably be any Moon base.

                             Bertrand MICHELET.

P.S.: In my previous message, I wrote that silly equation:
>   Delta( Log S )  = p/s.Delta( K.M/r + w^2.r/r ),
Integration of the 'w^2.r' term gives of course:
>   Delta( Log S )  = p/s.Delta( K.M/r + w^2.r^2/2 ),
as any undergraduate would have guessed. Oops... sorry... What is
the equivalent of a "lapsus calami" when one uses a typewriter?...

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

Date: 13 Nov 89 14:08:15 GMT
From: rochester![e-mail]  (Paul Dietz)
Subject: Protein Crystals Grown in Space Prove Superior

Science (11/3/89) has published a paper, and a news article, on the
results of protein crystal growth in microgravity on the shuttle.  The
paper reports on crystal growth experiments on STS-26 in Sept. 1988.
Three proteins crystallized -- isocitrate lyase, gamma-interferon D1,
and procine pancreatic elastase -- produced large crystals with
internal order superior to crystals grown on earth.

According to the news article (page 580), the crystals of isocitrate
lyase, a nematode enzyme, were so superior to earth-grown crystals that
they made the difference between go and no-go for a project at Dupont.
Dupont wants to use the detailed structure of the enzyme for the design
of new nematocides.  Crystals of porcine pancreatic elastase, an enzyme
similar to a human enzyme implicated in emphysema, gave an x-ray
resolution of 1.3 angstroms, vs. 1.65 for the best earth-grown crystals.
The gamma interferon crystals allowed the structure of that protein
to be solved for the first time.

On STS-26 they also tried to crystallize eight other proteins, but
all they got were showers of little crystals.  DeLucas, an investigator
on the team that flew the experiment, says this was probably due to
vibration causing too many crystals to start forming at once in a
supersaturated solution.  [Seems like a solvable problem.]

On earth, the density changes that occur when proteins crystallize
out of solution inevitably cause convection.  Experiments on earth
have found plumes rising off the growing crystals at up to 1 centimeter
per second.

    Paul F. Dietz
    [e-mail]

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

Date: 13 Nov 89 05:39:21 GMT
From: gem.mps.ohio-state.edu!usc!samsung!shadooby!mailrus!jarvis.csri.toronto.edu!utgpu!utzoo![e-mail]  (Henry Spencer)
Subject: Re: Radiation exposure for Apollo astronauts

In article <[e-mail]> [e-mail] (Mike Higgins) writes:
>...  A naked human in space is virtually
>transparent to cosmic rays: they pass right through all these big low density
>organic molecules that we are made of most of the time...

Unfortunately, a small fraction of cosmic rays are heavy nuclei, rather
than the usual light ones... and the naked human body is *not* transparent
to those.  They are thought to be the cause of the flashes of light Apollo
astronauts reported seeing with their eyes closed; the flashes are very
tentatively explained as heavy cosmic rays destroying retinal cells.
This is a major concern and considerably complicates the shielding
problem.  The radiation dose from light-nuclei cosmic rays in an unshielded
spacecraft is actually not big enough to be a major worry.  But blocking
the heavy cosmic rays requires enough shielding to generate a lot of
secondary radiation from the light cosmic rays, and stopping that takes
still more.
--
A bit of tolerance is worth a  |     Henry Spencer at U of Toronto Zoology
megabyte of flaming.           | uunet!attcan!utzoo!henry [e-mail]

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

Date: 15 Nov 89 00:29:53 GMT
From: cs.utexas.edu!samsung!shadooby!terminator!ronin![e-mail]  (Allan M. Bjorklund)
Subject: Re: HST Resolving power

In article <[e-mail]>, [e-mail] (Dan Mocsny) writes:
>In article <[e-mail]>, [e-mail] (Allan M. Bjorklund) writes:
> >
> >I redid the calculations, and came up with the HST being able
> >to resolve a 3000 mile wide object at 39 AU which is about 5.3 light
> >hours, which is the distance to Pluto. But unfortunately, Pluto is only
> >about half that in diameter.
>
>Gee, does that mean we can't discover Pluto until HST Release 2.0 orbits?
>

I was thinking more along the lines of resolving surface features on Pluto.

Allan Bjorklund                         Co-Administrator of the
[e-mail]            University of Michigan's MsDos Archives
[e-mail]           terminator.cc.umich.edu (35.1.33.8)
[e-mail]                cd msdos

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

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From: [e-mail]
Subject:  Hubble Space Telescope

  Thanks for setting me straight on the capabilities of the HST.  My knowledge
on such matters is sorely lacking.  I don't remember where I read the article
and I tried to look for it, but to no avail.

Andrew J. Greenshields

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

Date: 14 Nov 89 06:27:39 GMT
From: [e-mail]  (JOHNSON RICHARD J)
Subject: Re: Population pressure to move to space

[e-mail] (Sang J. Moon) writes:
< ... the population explosion resulting from lack of
< massive death [from war] will necessitate developing ways to put the
< surplus population into space or else we will have to have another war.

Wow.
But just in case this is really a serious post (I didn't see any smileys)...
Wars don't reduce population.  They cause an increase in the birthrate
when all the soldiers get home and decide to start families.

Besides, have you looked at what sort of space transporation capability
would be required to put a given amount of "surplus population" into
space?  I did once, but all I can recall is it required more capability
than the entire human race would be able to  afford given the high pop.
growth rates popular in the early 1980s.  Anyway, the resources required
to shift large amounts of folks could probably be spent more effectively
to raise the standard of living of the producers so they don't have the
time to create lots of kids.

|  Note - boulder is bad, spot is good.  Careful with the replies...  |

| Richard Johnson                           [e-mail] |
|    CSC doesn't necessarily share my opinions, but is welcome to.     |
|  Power Tower...Dual Keel...Phase One...Allison/bertha/Colleen...?... |
|   Space Station Freedom is Dead.  Long Live Space Station Freedom!   |

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

Date: 14 Nov 89 18:09:37 GMT
From: bfmny0![e-mail]  (Tom Neff)
Subject: Re: Space Elevator

In article <[e-mail]> [e-mail] (Raymond Blaak) writes:
>My intuition is that once the shuttle is
>loose [from the tether], the station goes flying off into a higher orbit.

The station's orbital change is continuous while the shuttle is unreeling.
Net effect is a boost, but considering orbital drag this cannot be a bad
thing.

Now, if we could just arrange to "hook" the shuttle and "reel it in" for
rendezvous, we could counteract that effect easily :-)
--
"NASA Announces New Deck Chair Arrangement For   \_/  Tom Neff
Space Station Titanic" -- press release 89-7654  \_/  [e-mail]

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

Date: 14 Nov 89 18:03:47 GMT
From: mailrus!jarvis.csri.toronto.edu!db.toronto.edu![e-mail]  (John Hogg)
Subject: Re: Space Elevator

In article <[e-mail]> [e-mail] (Raymond Blaak) writes:
>[e-mail] (Michel van Roozendaal ECD) writes:
>
>>... In this process angular
>>momentum was transferred from the shuttle to the station. We can now
>>disconnect the shuttle from the tether, and start reentry, having saved
>>a considerable amount of fuel.
>
>I was wondering what happens to the station at this point when the shuttle
>is disconnected. Its orbit is no longer what is was before, and thus
>propellant is needed to restore it. My intuition is that once the shuttle is
>loose, the station goes flying off into a higher orbit.

That's not a bug, that's a feature.  This is an excellent way to
reboost the station at no additional cost in propellant.

``Pinwheel'' or rotating tether proposals generally require that
payload up ~= payload down, so that a minimal amount of propellant
is used to keep the tether CG in the desired orbit.  They are
therefore best for situations in which traffic goes both ways.
In other words, they don't help powersat construction a lot,
but they can make space manufacturing economical for somewhat
less valuable products than would otherwise be the case.
--
John Hogg            [e-mail]
Department of Computer Science, University of Toronto

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

End of SPACE Digest V10 #246
*******************