Mining the Moons of Mars

--- In spacesettlers, "Marcel" wrote:

> You'd have to build a huge 2 kilometer in diameter 1-G
> habitat first before you shielded it which would be extremely
> expensive.

If one-third-G is enough for those living on Mars, then why
does the Deimos Companion Habitat (DCH) have to be a full G?
Also, you can have faster than 1 RPM of rotation, if you
screen your miners for tolerance of that. Put those two facts
together, and you can have a much smaller habitat.

But OK, let's say it does have to be 2 Km across. So build
three spherical pressure shells, each fifty metres in diameter
and each massing 120 tons. Assume that by the time you fill
one with all the stuff you want to have in there, it masses
150 tons. So now your three fully-outfitted spheres mass 450
tons. Line them up, one thousand metres apart, and connect
them with a butt-load of tethers, maybe 100 tons worth. Add
25 tons of PV and radiators and such. So now you're up to 575
tons of stuff. That leaves you with 425 tons before you hit a
thousand. Pack 525 tons of unprocessed, undifferentiated
ground-up Deimos around that central sphere. If possible,
arrange for Deimos to always be between the DCH and the Sun.
Set the whole sh'bang to rotating. As you mine Deimos, pack
the tailings around all three spheres.

Voila, home for 300 people. If fifteen score folks is too
many, then make it 30 or even 25 metre spheres, with related
savings in mass. And of course, the fewer people you need,
the pickier you can be with things like tolerance of high
rotation rates.

> But you could pretty much get the mining facilities going on
> Phobos and Deimos by living in small prefabricated structures
> on the Martian moons shielded by the materials on those moons

Yep. And stringing two of those "small prefabricated structures"
together with tethers and whirling them around gives you all the
benefits of space and all the benefits of Mars (except two or
three, which I will address in a separate post).

> and on the surface of Mars with perhaps just a few dozen or a
> few hundred people.

There are good reasons to have dozens, scores, even hundreds of
people on Mars, but making it easy to mine the moons isn't among
them. Again, I'll address it in another post.

> That doesn't mean that large rotational habitats with hundreds
> or perhaps thousands of people will not eventually appear in
> orbit around Mars.

In the immortal words of Shaft: damn right.

> But we should try to get things going as cheaply as possible
> as soon as possible.

Which is why you would build things for a dozen people first,
then for thirty or so, then for a hundred, and so on.