space ores

Mike C wrote
> ... a tether-powered habitat would pay for it's electrical power
with a constantly lowering orbit.

Yes, given solar power in space, this ED use of tethers might not be
worth the loss of height.
Consider also that a tether could drop payload aeroentry barges to
sale. Drop something going down, and get a boost upwards. Drop it
with minimal propellants, as an added bonus.
Aside from that, I doubt that any space manufacturing facility would
be in so low an orbit, and if it were, it's more likely to use ED
tethers to raise itself.
HEEO, or the 2 week resonant orbit is always above 10,000km,
correct? At the apogee, it's way above the Van Allen belts, so very
little ED activity, I believe. No air friction so high.

>... barring the government doing it for us, that the biggest
majority of people funding development of space will be doing so with
no particular interest in space settlement. That means we must have a
profitable business plan.

How about GEO antenna platforms (& satellite maintenance?), and
asteroidal metals? Both more near term than SSPS, though both lead up
to it.

> I can almost see a case for the platinum group metals. And even
here, you'd have to be careful about flooding the market. But for
anything else, I think it would be hard to make a profit.

Well, if our (the space miners) economics allowed it, we could maybe
deliver steel or something else equally prosaic to any port city on
Earth for a competitive cost. Maybe it will be a while before
anything less valueable than Pt or crystals/pharmaceuticals is worth
it.

>> I think that space-mined ores can be brought down to Earth on a
relatively inexpensive way. You have simply to encapsulate them in
some heat-resistant envelope and drop them into the atmosphere...
bulldozers and trucks could "re-mine" the debris on the surface.
>
> I remember a proposal to form space metals into a giant lifting
body. Ocean landing was recommended, as the lifting body would
actually float, and could be towed. That's because it was foam
steel: something which was suggested as an space export before
honeycomb composites made it seem less attractive.

What if it's just got enough foam or simple air or vacuum pockets to
allow it to float?
I never entirely followed the idea of simply dropping a cast body of
foam iron, and then cutting it up on the ground. Too cute. Better to
include foam steel and space alloy parts of a standard size/shape, or
even the finished parts the customer orders. The aeroentry barge body
is just dumb foam concrete or something expendable.

> I'd say the chief problem would be explaining to folks who've seen
"Deep Impact" and "Armageddon" what you were going to do and why they
shouldn't worry about it.

Sell tickets to ride in chase planes to watch it drop in, or sell
pieces of asteroid materials as trinkets or watches.("Moychandising,
moychandising" Yogurt said.)
Probably easier than convincing some people that we know what we're
doing, and that hollywood doesn't. I still hear complaints about the
callous disregard for all life on Earth NASA displayed when they
risked crashing Cassini when it made its last flyby. Never mind that
it hit it's target pass orbit by a 4 mile margin.