[ExI] Mining the Sky SL Talk I gave today

[samantha]

spike wrote:
> ... 
>> ...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:
>>> OK, I thought about it longer.  Now I will now explain my 
>> thoughts in a parable...Jesus.
>>
>> It is also flawed.  I have already explained most of the 
>> errors (like your assumption that platinum has no 
>> non-financial value on the ground, or even that the value in 
>> orbit necessarily dwarfs the value on the ground*)...
>>
>> * Another way to think of it: even if the eventual value in 
>> orbit is extreme, that's still eventual.Arian
> 
> Ja, my notion is that platinum creates its own value in orbit as soon as we
> figure out how to use it to make reflective surfaces.  In the asteroid belt,
> we have plenty of iron, plenty of silicon.  These are good structural metals
> but neither of these are particularly good reflectors in the sunlight
> spectrum.  We use the platinum, chromium and silver as reflective layers
> over the iron and silicon.
> 

I understand that there is a fair amount of aluminum silicate around. 
So aluminum backed mirrors shouldn't be that difficult from material on 
hand.  Or just aluminum lightweight shells for that matter.

> We already have this technology.  Imagine a very thin mylar balloon, 100
> meter radius, launched gently from an asteroid, in interstellar space far
> from the nearest gravitational influence, inflated to about 10
> nano-atmospheres, with a free-floating ion-deposition gun inside the
> balloon, vaporizing a ten kilogram hunk of chromium or platinum.  The
> balloon is set to rotation about the X axis, the ion gun rotates about the Y
> axis, while spraying a tenuous mist of vaporized metal at a rate of about a
> milligram per second.  The inside of the balloon is eventually coated with a
> reflective surface.  Cut circular pieces out of the balloon, reshape
> slightly and you have an enormous solar concentrator.

Wouldn't it be as easy to paint the outside and then pop the balloon?

> 
> The free floating ion deposition device need not be connected in any way to
> the balloon, for as the ion gun drifted toward the wall of the balloon, the
> force of the ions hitting the nearer surface would gently nudge the balloon
> away, keeping the ion gun roughly near the center of the balloon.  
> 
> With the numbers I arbitrarily called out, the average thickness of the
> coating would be about 4 nanometers, or close enough to 30 atomic radii for
> platinum.  The ion gun I specified could work on solar power alone at that
> flux level and would accomplish the complete ionization of the 10 kg mass in
> about four months.  A 15 atom thick average coating of chromium on mylar
> would reflect about 20 percent-ish of the sunlight that hits it (if I recall
> correctly.)  
> 
> What could we do with that?
> 
> We have all the technology needed to do this today, with the possible
> exception of the device needed to cut circular pieces of the balloon and set
> them to gently rotating.  But that doesn't sound too hard to me.  The
> platinum would make great solar concentrators and solar sails.  I see little
> justification for dropping down into the gravity well to collect interest on
> it, instead of going straight to the solar sails now.

How hard is a cutting torch given the materials on hand on using a solar 
furnace to drive it?  Lasers shouldn't be hard to power either.


- s