[ExI] solar power satellites

[hkhenson]

At 08:28 PM 5/19/2008, you wrote:
>Keith:
> >Unfortunately, no.  And the lift from LEO to GEO takes about 70% of
> >the mass in LEO to get it up to GEO.
>
>Any help from partially deploying your solar panels and using ion
>thrust to do the transfer to GEO?

The trouble with ion engines is that they generate so little thrust 
that it takes more than a year to get to GEO.  I suspect the bankers 
are not going to like the delay.  The other problem is that a power 
sat is huge.  Going up slow means it gets bashed by space 
junk.  Still, most of the work on power sats to date assumes 
constructing them in LEO and doing exactly that.

>Also, a small prototype in LEO might be acceptable, and could provide
>intermittant power for disaster recovery, for example.

It's been discussed.  The Japanese have been doing most of the 
work.  I don't think it is worth the trouble because LEO has problems 
with ionized gas that you just don't get at GEO.

Most of the advocates talk about a 20 year program to build a one GW 
test power sat.  It's interesting as a research project but in terms 
of solving the energy crisis it's useless.  Just way too slow.  We 
need to be deploying these things at a very high rate in the next 5-7 years.

Keith