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From: dietz@SLB-DOLL.CSNET (Paul Dietz)
Newsgroups: net.space
Subject: Re:  Contribution to 'scuttle the Shuttle' debate.
Message-ID: <8602121930.AA00597@s1-b.arpa>
Date: Wed, 12-Feb-86 13:06:28 EST
Article-I.D.: s1-b.8602121930.AA00597
Posted: Wed Feb 12 13:06:28 1986
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> 1.  SPSs.  Not even Gold will argue that SPSs won't be important within 20
> years.  Now most feasible SPS designs call for solar panels on the order of
> kilometers across; you aren't going to ship that up in one shot.

I'm sure he would argue that.  Gold has a radical hypothesis that huge
amounts of abiogenic methane are trapped deep in the earth, and believes
there may be huge amounts of geopressured methane in the deep crust.  If
true, this would mean fossil fuels could supply us with energy for
generations.  Also, the NAS study of an earth-launched SPS concluded
that it wouldn't be competitive with more conventional power sources,
even if launch costs from earth are reduced by orders of magnitude and
cheap, lightweight, efficient GaAs solar cells can be developed.  Face
it, no one is going to build SPS unless it promises *much* lower cost
energy: it's just too risky.  A cheap SPS needs cheap extraterrestrial
material, which means an automated or remote controlled lunar mine.

> 2.  The Space Station.  All right, Gold and Van Allen probably think it's a
> boondoggle, but as a platform for launching planetary probes it can't be
> beaten. 

I suggest that empty space would make just as good a launching platform.
The only sorts of manipulations you would reasonably perform on a probe in
orbit are things like mating together prefab modules and fuel tanks or
loading fuel (chemical or nuclear); that could be done just as well without
a space station.

> Further, I don't know of any geologist who would be prepared to
> argue that he could learn more from a series of unmanned probes in LEO than
> a fully-equipped lab manned by geologists in LEO.

But could we learn more from 8 billion dollars worth of unmanned
scientific instruments in LEO, or from a few hundred million $ in
instruments attached to an $8 billion space station?  It's not obvious
that the much greater expense of the space station buys you much.

>  Hence we should
> expect that the Space Station and SPSs will be constructed primarily by
> humans; and that in turn means we need to send more shuttles up now.

Rick, I think you're being selectively myopic in your projections of
future technology.  By 25 years from now computers should have as many
bits of RAM as the human brain has synapses (assuming costs continue
to go down by a factor of 4 every 3 years or even somewhat slower).
Logic chips should be housing 10**8's of transistors.  If ESA thinks
teleoperators can be made now then what will the situation be when
computing power is 100 to 1000 times (or more) cheaper?  Building an
SPS in space from earth launched material needs launchers to LEO
at around $10/lb, and even then it's just competitive with earth-based
power supplies.  I don't know anyone predicting we'll have launchers
this cheap in 25 years.  The only reasonable scheme for exploiting
lunar resources I've seen needs teleoperators on the moon, otherwise
the system requires far too much mass to be imported from earth.

Your argument seems to be: there's a lot that should be done in space
RIGHT NOW, and there's no time to develop teleoperators.  The
counterargument is that there's little that can be reasonably (read:
ecomonically) done in space right now, or even soon (until somewhat
cheaper launchers are developed), and any big project in space will
be very expensive, so why not use some of the funds to develop
teleoperators?