Mining Asteroids

> From: Combs, Mike
> I wonder if the Summer Study goes into any detail about why the lunar
> rotary pellet launcher was dumped in favor of the mass driver.

Remember that what they really wanted was a great big sniper rifle - that is
a device that will throw a weight at high speed and hit (or at least
rondavouse with) a target that is both moving at at great distance. We have
much more experience doing this with linear devices rather than rotary ones,
and the technology is much more mature. With a rotary launcher slight
changes in friction as the pellets go down the tube could make aiming very
difficult.

> From: Lucio de Souza Coelho
> you can go to the other side of the inner Solar System or
> you can go mere 360 Mm away and mine the bottom of Moon craters

Except the useful moon craters will no doubt be hundred of km apart, and it
will be difficult to build many mining stations, or build one mining station
that can move places. With asteroid mining you have just one processing
facility, and tugs that bring the material to you.

> From: dsw_s
> A crucial question, as has been raised
> many times before, is what's in it for the earthlings?

Endless current-cost energy for the next fifty years. Let's face it, whether
it's in the ground or not, oil is NOT going to be an economically stable
fuel over the next few decades. The cost will continue to rise as the
developing nations start to demand more of the stuff, and fluctuate
endlessly according to Middle East polotics. The SSPS concept could pay for
any amount of space development.

There are many important materials which are rare or inaccesable on Earth,
and which could be obtained for lower cost as a 'side line' while peopel are
mining for more common and useful materials.

Any material minned can be sent to pretty much any position on earth quickly
and cheeply. Look up the logstics of building a bridge. The pieces of metal
are V E R Y L A R G E and it ishorribly difficult to ship them across
country. Build them in space though, and you can just sofft-drop them into
the nearest lake or corn field.

Developed nations will may not be able conpete with developing nations that
have advanced technology but low wages. Space may be a break out industry
for the US and EU. both have spent a lot of time thinking about how to get
into space and what to do when you get there. China probably doesn't have
the same library of creative forward thinking to draw upon, and India
definately doesn't.

Imperial Rome syndrome. Civilisations that don't look inward collapse
inwardly and terminally.

Sun Shield system. Put enough very large solar sails betweeen the earth and
the sun and you can affect how much energy reaches earth, and hence regulate
Earth's tempreature - in theory enabling you to reduce, stop or even reverse
global warming. According to many climate theories, even very small
influences can have very large effects.

> From: Richard
> Such inflexibility when we don't know that much
> about what is out there is scary.

We may not know what's there *exactly* but we do know how difficulty it will
be to get it somewhere we can atually use it. for a very long time the last
location will either be Earth orbit or (at a pinch) Earth's surface. It's
relatively simple mathematics to work these things out - and the sums simply
do not come out in favour of the moon.

> We haven't gotten anything from the asteroids

Mass spectrometer.

John