models support NEO material deposits on the Moon

--- In spacesettlers@yahoogroups.com, Joe Strout wrote:
>
> On 5/30/13 1:11 PM, brooksn wrote:
>
> > But if we capture small asteroids already on a near miss with Earth and
> > bring them into lunar orbit all the cons you listed go away.
>
> That's true. But we can only do that with very small asteroids.
>
> > And if prove that one can be captured and mined, then we can capture
> > 100 the same way.
>
> True, but it's likely to cost 100 times as much (and take 100 times as
> long) as one. Maybe not quite; we'd certainly learn to do it better
> with time, and get some savings from more frequent launches. But I
> don't see the same economies of scale you'd get from planting mining and
> launching equipment in a fixed place on the Moon.

Huh? You launch a probe, like NASA's, capture a small asteroid on a collision course with the Earth/moon system. Place it in lunar orbit to mine. Water will be a regular commodity, use H2 and LOX from water to refuel the probe, send it out for another asteroid. This removes the Earth launches from all future asteroid captures, except the first. Also the mining facility is a one shot into lunar orbit. All that's left is transporting any commodities to GEO, LEO or Earth.

All moon mining ore or products need to be launched from the lunar surface, with much more gravity. And the lunar miners have only half the solar energy.

> > I think Bigelow is interested in space generally and his habitats
> > everywhere specifically. I don't see the advantage in the moon over
> > captured lunar orbiting asteroids. Given everything it takes to do both
> > it seems the lunar asteroids should beat the moon every time.
>
> If we imagine a ready supply of already-captured asteroids, yes. But
> lacking such lunar orbiting asteroids, a big deposit on the Moon easily
> beats a tiny rock millions of miles away.

This assumes a big deposit waiting for us on the moon, as yet not confirmed to exist at all or for that matter been surveyed.

Even assuming both of us found our perfect candidates. Let's compare: Send a small probe to barely move an asteroid to capture it, mine it, and send the products on its way. Or send the miner to the moon crater, land it, mine it, then launch it from the surface. I'm not sure how the moon easily beats the asteroid in this scenario? The landing on and launching from the moon are significantly more costly than the asteroid alternative.

> Now, if we could show that there was already PGM-rich material lounging
> around at L2 or some such, that might be another story. That could well
> be worth exploiting. But I'm not aware of any indications that
> significant amounts of material exist there -- such orbits are unstable
> in the long run, I believe. (Somebody please correct me if I'm mistaken.)
>
> Things on the surface of the Moon, on the other hand, are extremely
> stable. The Moon's been collecting material for us, albeit at a slow
> rate, for 4 billion years... I think it's about time to cash in!
>
> Look at it this way: we both agree that asteroids are a good source of
> material. We also both agree that having them in the vicinity of the
> Moon is quite convenient. We differ only on one minor point: you want
> to go take small asteroids that aren't already in cislunar space, and
> wrestle them into a convenient orbit; I want to use much larger
> asteroids whose orbits have already been altered (quite abruptly) for
> our convenience.

The 'wrestling' of these very small asteroids into a lunar orbit when they are already 'generally' headed to the Earth/moon does not seem like it would take a monumental feat. Were I'd say we disagree is that you think landing and launching to and from the moon is almost inconsequential when compared to dealing with small asteroids in orbit.
Brooks