Re: Humans doomed without space colonies, says Hawking

From: Andrew Clough (
Date: Thu Oct 18 2001 - 12:20:59 MDT

At 12:08 PM 10/18/2001 +0200, you wrote:
>On Thu, 18 Oct 2001, Andrew Clough wrote:
> > still seems a good investment. I suspect that we could get an astroid into
> > medium Earth orbit with not too much equipment mass. On the other hand,
>A cubic mile of nickel iron, with a delta vee of how many km/s? 5, 8?
>That's a lot of driving mass, even assuming plasma drive speed of exhaust.
>Would make more sense to turn the asteroid into 1-10 um foil, and use
>photonic pressure to kill enough delta vee for a gravitational capture.

Of course it would be unreasonable to bring that much reaction mass to the
asteroid. We might find asteroids in really odd orbits where it might be
possible, but I did envision at least using the asteroid itself for
reaction mass in some sort of solar powered ion thruster, or maybe magnetic
or solar sails; again depending on the asteroid's orbit.

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