Water from space

From: spacesettlers@yahoogroups.com
[mailto:spacesettlers@yahoogroups.com] On Behalf Of Douglas May

> The best source of ice will be comets, I
> believe, and a good function for a 3rd or 4th generation space colony
> would be to mine water from passing comets.

I hope you've had a chance to see "L5: First City in Space".
http://members.aol.com/oscarcombs/links.htm#L5-FCiS

> Long story short: I see
> neither Lunar ice nor Martian ice as being of much long term aid
> towards settlement of space stations or planetary colonization.

I think the water resources of the moon, limited as they are, might be
enough to "prime the pump" industrially and economically until we are
far enough along to begin tapping into NEOs.

Where Mars is concerned, I think the relative steepness of the gravity
well is more the showstopper than the scarceness of the ice (although I
had someone argue this point with me once).

> Orbiting space stations in the asteroid belt and beyond have a much
> better prospect of gathering large amounts of ice.

Which is why I think in the long term, the parts of the solar system
from the Belt outward will be where most of the action is happening.

> But the winds only blow outwards. How
> could we cheaply bring the ice back to this altitude?

Solar sails can angle to bounce sunlight in the direction of orbit, thus
slowing and dropping inward. Thus a kind of "tacking" maneuver should
be possible.

> Would we be
> better off just placing all the colonies out there where all the ice
is?

My prediction: In the near-term, habitats will be built close to Earth
because at the start, Earth is the only customer in existence, and one
should be close to the market being served. But in the longer term,
Earth will become a smaller and smaller part of the overall economic
picture, and then the availability of hydrogen and other volatiles will
make building settlements in the Belt and outward more economical.

Regards,

Mike Combs