[ExI] Power satellites

[hkhenson]

At 12:30 PM 5/1/2009, Ben Zaiboc wrote:

snip

>OK, I'm way behind on this list, so someone may have asked this 
>already, but I'm interested in the issue of NEOs as a source of raw 
>materials, and whether this is even remotely feasible.

Sure.  A reasonable mass budget for a processing plant is ~50,000 t 
or 5 million kg.  At current launch prices, it would cost $1000 
billion just to launch it.

>I'm thinking NEOs, like most things in space, go fast, relative to 
>the earth.  Really fast.  Getting to them, extracting useful 
>resources and getting back with those resources isn't at all like 
>drilling for oil or digging up metal ore here on earth.  I suspect 
>it's possible that the energy required to get there and get the 
>hydrocarbons or ores or whatever back, would far outweigh their value.

>Anybody know some hard facts about this?

In the context of a power sat construction project that is using a 
million tons per year of materials, it's just a matter of delta V and 
payback time.  For example, GEO and asteroid 1986 DA are only 140 
m/sec from each other.  If the processing plant was turning out 2% of 
its mass per day, in say Invar, it would take 50 days for the 
investment in the processing plant to repay its mass.

Simple math.

It does take some design thought.  My suggestion is an open ended 
induction furnace where the metal is drawn off in a fast moving rod.

Keith