New Book on Space Colonies

> I think you can only make sense of a PGM exploitation mission in
the
> context of at least some orbital infrastructure. OTOH, if you
simply
> vapor deposit the PGMs onto the inside of balloons you might end
up
> with sufficiently low ballistic coefficient that just dropping the
> resulting hollow sphere in the desert somewhere would be
practical.

Interesting idea. I wonder if it would really work? How much PGM
ablation would there be? How much would that cost? :(

You
> wouldn't want to just drop solid lumps of PGM because they'd bury
> themselves on impact if they didn't vaporize.

Yes, I know. People might not be too happy having solid chunks of
metal impacting the Earth.

For a taste of what might be the future response to such a proposal
see:

relevant quote:"The TransOrbital venture could be disastrous for the
globe - no scientist today could predict yet how adding mass to the
moon via human infrastructure or removing mass, via mining, will
impact the delicate gravitational interplay between Earth and its
only satellite. The moon belongs to all the people of the Earth -
not to George. W. Bush or his friends at TransOrbital."

That said, if it was acceptable, and made economic sense, there'd be
nothing wrong with having a mining operation on-site to dig up the
impacted PGM.

>
> Alternatively you can just send up a supply of heat shields. I
think
> you probably don't want to invest any money in trying to bring the
PGMs
> back to a spaceport in an RLV. Just drop them in big chunks near
the
> facility that will further process them.

But drop them how? That's my whole point. The prospect of PGM mining
in NEOs is alluring but if there is no market for them in orbit,
then the make-or-break factor becomes that last 100 miles to Earth.
Most everyone references the mining aspect but I haven't seen
detailed planning on the Earth re-entry aspect that brings the PGM
to market. That's what I'm really curious about.
>
> > Can specific infrastructure in orbit for PGM mining help other
> > industries? How?
>
> Anything in LEO that's specialized for providing delta-v is
useful.
> Also anything that's capable of repair and refurbishment is
useful. If
> you have a regular stream of PGM mining ships headed out to NEOs
it
> makes it easier to send out a ship to mine volatiles (or more
likely it
> would happen the other way). Just having regular launches of
anything
> at all would bring down prices.

Yes indeed, but the very point you're making supports my argument
about economic interlinkages for orbital infrastructure. The PGM
venture needs other infrastructure to make its mission more viable.
Does it fund all of this ancillary infrastructure only in order to
enable its prime mission? That's a heavy overhead. Bootstrapping in
this way is going to be might hard.

>
> >> Platinum isn't the most useful - Rhenium has the highest melting
> > point
> >> of any metal, and it's insanely expensive. Dropping the price of
> >> rhenium may help drop launch costs,
> >
> > Can you tell me more. How is Rhemium used in launch vehicles? I'm
> > assuming it has something to do with rocket nozzles?
>
> Rhenium is used in radiatively cooled nozzles. If it was cheaper
it
> would probably also see use in turbopumps for the turbine blades
(which
> see very high heat loads from the gas generators). Also it could
be
> used in thermal protection for reentry, though I think it may be
too
> easily oxidized to be used without some sort of coating. If the
price
> comes down then it may be possible to come up with an alloy of
rhenium
> and something else that can serve as TPS without oxidation
concerns.

Good info. I'll file this away for future use. Thanks.

> > As a scientist how would you go about finding more information
so as
> > to make a better proposal? What info are we missing?
>
> The single biggest problem I foresee is in working with ultrafine
> particles of asteroid regolith in micro gravity. The dust is going
to
> get everywhere, and it is *fine* - moving parts will quickly
destroy
> themselves if not protected. As soon as you scoop up a little bit
of it
> you are surrounded by a cloud of dust.
>
> The other major problem I see is simply finding the right
asteroid.
> Really good ore bodies are on in ten thousand or so. Lousy odds.

Hmmm. I wonder what the odds are here on Earth? What technology can
be used to better our selection process.

Perhaps an orbital spectrascope. Then dozens of microsatellites to
the likely NEOs. After their analysis, launch more complicated
landers and crawlers to sample the various sites on an NEO. Then
finally a mining mission.

We can't really prospect in the old tried and true ways, can we?

Check out this photo I've uploaded. In the Photos section of the
website or go here:
=Lunar+Prospector.jpg&.view=t&.done=http%
26.view=t

For
> volatiles the odds are much better, maybe one in a hundred or so.
I
> have ideas about how to do the prospecting, but it's been a while
since
> I really looked closely at them. I should dust off my old notes
and see
> if the ideas hold up in light of what I've learned. It'll be a
while,
> but I'll post something here when I finally get around to it.
>
> ......Andrew

Looking forward to what you have to say. The details make things
more real for me.

TangoMan