REM%MIT-MC@sri-unix.UUCP (01/15/84)
From: Robert Elton Maas <REM @ MIT-MC>
Date: 13 Jan 84 15:22:45-PST (Fri)
From: ihnp4!ihuxp!wbpesch @ Ucb-Vax
... I think economically [asteroids] is the feasible way to support
free-standing space stations, not from the gravity well of Earth or
any other major gravity well.
On the other hand, there's an awful lot of oxygen on the moon, and
lots of aluminum silicon and titanium also, and the moon is at a
constant distance from Earth, closer than virtually any
"Earth-crossing" asteroid, and its surface has already been surveyed in
a few spots so we're not guessing. Therefore, if we can get a
mass-driver working on the moon which runs automatically without
humans on the premises, tossing moondirt into space then moving to a
new location to find some more lose moondirt, let's not ignore the
Moon. I say use Moon for supplying all materials it has in abundance,
taking advantage of its easy location (albeit uneasy gravity well, but
I think we can overcome that with mass driver), and also use the
asteroids, for the stuff they have in abundance (iron, carbon,
hydrogen, etc.; but we don't know for sure yet, none has yet been surveyed).
Ok?
But I concur that processing and fabriction should be done in zero-gee
mostly, not on the Moon. Collect moondirt and asteroid-chunks in low
lunar orbit or at L5 or elsewhere in Earth/Moon vicinity, and do
processing there.wbpesch@ihuxp.UUCP (Walt Pesch) (01/16/84)
First let me say that the basic idea brought up by < REM @ MIT-MC >
is valid in that a mass accelerator based on the moon would be
worthwhile for industrial purposes. For the simple fact that the moon
in comparision to an asteroid is a limitless supply of materials. And
the mass driver does overcome the problems of the gravity well. The
only problems that could be brought up would deal with the cost of
establishing the mass driver, and the technology to create and
maintain the mass driver both on the sending and on the recieving
ends. But this role would be in a support role for near-earth bases,
for the asteroid belt (which is the logical place to go) would be a
little too far. I think that there is the minerals available in the
asteroid belt without the necessary cost of importing them.
I would also like to bring up the additional question to those in
net.astro(.expert) as to what the actual compositions of asteroids
are. The question could also include the theories as to whether the
asteroid belt was once a planet, or is natural. Is there a source
that I can refer to on what the various types of asteroids there are,
and the mineral contents of the various forms of asteroids.
One thing that I have thought of is that if the asteroid belt is a
broken-up planet, then perhaps not only would the inner parts of an
actual planet be available for study, but also the deep minerals would
be available for easy strip mining. Therefor increasing the value of
these colonies, and also we can see a worthwhile increase in the
economic worth of asteroid mining colonies.
Walt Pesch
AT&T Western Electric AT&T Technologies
ihnp4!ihuxp!wbpeschmmt@dciem.UUCP (Martin Taylor) (01/19/84)
=============
I say use Moon for supplying all materials it has in abundance,
taking advantage of its easy location (albeit uneasy gravity well, but
I think we can overcome that with mass driver), and also use the
asteroids, for the stuff they have in abundance (iron, carbon,
hydrogen, etc.; but we don't know for sure yet, none has yet been surveyed).
Ok?
But I concur that processing and fabriction should be done in zero-gee
mostly, not on the Moon. Collect moondirt and asteroid-chunks in low
lunar orbit or at L5 or elsewhere in Earth/Moon vicinity, and do
processing there.
==================
Why not process on the Moon, at least the refining of materials.
It seems quite reasonable to design an automatic isotope refinery
for lunar surface operation, and presumably it would be better
to transport isotopically pure elements that are wanted rather than
the aggregates that are in the whole soil mass.
As I see it, the refinery would be a sort of lunar-rover/mass-spectrometer.
A digging mechanism would deliver soil, suitable fined, to the focus
of a solar furnace that formed the source for the mass spectrometer
section. The delivered ions would be received on a series of belts
or buckets (remember the Moon is in a better vacuum than we can
achieve in our laboratories, so these receivers could be a long distance
from the source). The receivers could be shielded from sunlight, so
most isotopes would form frozen solids that could be collected
every lunar night and the desirable ones sent where they are wanted.
The rover could slowly move across the lunar surface in a random
way, or could create a widening circular pit like a strip mine.
Is there anything wrong with this conception? Wouldn't it be economically
viable even now for producing valuable and exotic isotopes for
Earth use?
--
Martin Taylor
{allegra,linus,ihnp4,uw-beaver,floyd,ubc-vision}!utzoo!dciem!mmtal@ames-lm.UUCP (01/24/84)
I think asteroids are a great place to build things, but the moon will undoubtedly be developed first. The reason is that Lunar oxygen could be 8/9 ths of the weight of the fuel for an O2/H2 orbital transfer vehicle based at the space station. I saw a presentation by (I believe) Lockheed at the 81 Princeton Conference on Space Manufacturing that indicated a positive ECONOMIC return for lunar oxygen with moderate LEO (Low Earth Orbit) to GEO (Geosynchronous Earth Orbit) traffic in the 90's or so. There was a paper in one of the aerospace professional magazines a few months ago with a similar conclusion. I suspect that we'll have definit plans and funding for a lunar oxygen mine before 2000, work may even have started. I'm afraid the asteroids will have to wait for solar sails for profitability, so lets all pull for the World Space Foundation (they're building a solar sail).
flinn@seismo.UUCP (01/31/84)
What ever happened to Jim Arnold's hypothesis that the permanently shaded craters near the Moon's poles might contain water ice from cometary impacts? I think he estimated that there might be several cubic kilometers of ice there.
REM%MIT-MC@sri-unix.UUCP (02/02/84)
From: Robert Elton Maas <REM @ MIT-MC>
Date: 30 Jan 84 15:10:52-PST (Mon)
From: hplabs!hao!seismo!flinn @ Ucb-Vax
What ever happened to Jim Arnold's hypothesis that the permanently
shaded craters near the Moon's poles might contain water ice from
cometary impacts?
I've seen no interest from Ronald Reagan or Congress on this matter,
and it would seem infeasible at this time for any private company to
invest funds in exploring that potential resource. Thus we're in a
helpless position, with this possibly being the critical path to
fullscale habitat and/or manufaturing in space (water is needed for
raising food and drinking, and hydrocarbons are needed in industrial
processes). I wish there was some way to get our government to fund
the investigation of this process. (Maybe after a private company
finishes the ion rocket they're developing, it'll be feasible for
somebody to use it to get into polar-lunar orbit without government
funds.)al@ames-lm.UUCP (Al Globus) (02/03/84)
Sorry Dani, launch cost to LEO is more like several thousand dollars per pound, not $1,500. The $1,500 cost is, I believe, derived from highly subsidized shuttle launch costs. It is official NASA policy to gradually raise prices until full fare is really paid. As for the 'lower' costs of shuttle derivatives, I wouldn't count your chickens before the vehicle is off the drawing board. The shuttle was supposed to bring launch costs down to around $500/lb., something which has not and will not happen. In fact, if real costs come to within a factor of five of that level the shuttle folks will be very happy. What does all this mean? It MAY mean that lunar oxygen will be a paying proposition in a couple of decades. By the way, my letter never got through, thanx for the comments on the comet idea.