John Schilling wrote:

What sort of asteroid were you imagining had useful concentrations of
Nitrogen, again?


That's not a asteroid, that's a comet with methane ice on it.
And the only ones with _that_ still intact are going to go through the
inner solar system like a bat out of proverbial Hell, and be very
difficult to move into Earth orbit.

And the Moon seems scarcely better, though it's at least different and
it's big enough that there's still room for surprises. Mostly, though,
both the Moon and the Asteroids are very boring, geologically speaking,
each rich in about half a dozen or so sorts of useful stuff and that's
about it.


Particularly the Moon, which was originally formed off of the blasted
off outer lithosphere of the proto-Earth, only high in the lighter
elements and metals.

For the full range of minerals you need to support a civilization, you
really want something with a more interesting geology.


Though if you could somehow figure out a way to get a couple of cubic
miles of nickel-iron into HEO, your stainless steel requirements for
space colony construction would be taken care of for quite some time.
You're going to need something like the biggest Orion nuclear pulse
engine you ever laid eyes on to pull it off though.
The pusher plate would be huge, and have H-bombs detonating behind it. :-)

Pat