🚀 go-pugleaf

In article <369@hydra.gatech.EDU> dsm@prism.gatech.EDU (Daniel McGurl) writes:
>Ah, but you miss a critical point, the only fuel required is to get out to the
>Asteroid belt.  Getting the asteriods back involves just giving them a push
>of sorts (unless you are in a hurry...

Pushing even a small asteroid -- say a mere million tons -- into an orbit
that crosses Earth's is going to require more than a little bit of fuel.

>... Also, the space ship could probably slow in a
>way similar to the shuttles when it returns to Earth, just use the atmosphere
>as a speed brake.

At the kinds of velocities we've been talking about, no it can't.
Aerobraking works fine at a few kilometers per second.  At thousands of
kps, it doesn't work at all:  you have your choice of vaporizing, slamming
into the ground and making a large crater, or zipping off into space after
losing only a small fraction of your speed.  There is no way you are going
to lose hundreds or thousands of kps of speed in a distance of a few
thousand kilometers without vaporizing.  (Not to mention the small problem
that this involves decelerations of many thousands of Gs.)
-- 
Welcome to Mars!  Your         |     Henry Spencer at U of Toronto Zoology
passport and visa, comrade?    | uunet!attcan!utzoo!henry henry@zoo.toronto.edu