[ExI] Mining the Sky SL Talk I gave today

[spike]

> ...On Behalf Of Adrian Tymes
> Subject: Re: [ExI] Mining the Sky SL Talk I gave today
> 
> --- On Mon, 4/26/10, spike <spike66 at att.net> wrote:
> > ...
> 
...
> > In any case, I continue to think none of it would be worth 
> the cost to 
> > re-enter the atmosphere for the small amount any material 
> is increased 
> > in value here vs in space.
> 
> Current spot price of platinum, USD per kg, for delivery to 
> points on Earth's surface: 56,200.
> 
> Current spot price of platinum, USD per kg, for delivery to
> orbit: 0.

Ja.  If platinum is still that cheap, I have a hard time imagining it could
be mined at an asteroid and re-entered for that price.  Without a space
shuttle or equivalent, we need to hoist a reentry vehicle to at least LEO at
$10k per kg, and it must be a fairly sophisticated re-entry body, steerable
and recoverable, ideally non-destructively landable.  With those
constraints, I have a hard time imagining a landing mass fraction higher
than about .2 to .25, which takes us already up to $40 to$50k per kg range,
before we take into account a lot of the risk factors and the delta V needed
to rendezvous with the reentry body in LEO.  

It wouldn't be an easy task from an engineering point of view, and durn near
impossible I would think, with payload values as low as $60k per kg.

We would need to do some concept level engineering and fire up some
spreadsheets.

spike