another dissapointment

> My dissapointment relates to two points which were not in the article.
> 1) the use of materials from the moon or asteroids to build the
> satellites (as opposed to sending power from the moon) and

I mentioned Criswell - this is a way to lower the mass required to
be launched from Earth (by sending manufacturing equipment instead of
the final components). I think both options deserve study - unfortunately
the NASA SSP group did ignore this, with the limited funding they had.

I still haven't seen a concrete proposal for use of lunar or
asteroid resources that allows a utility scale plant to be built (under
$10 billion for several GW power). If you know of one I'd be very
interested.

> 2) the use of Solar Thermal via mirrors and a Barton or Stirling engine,
> as opposed to PV

I did mention PV in one spot, but mostly referred to generic
"solar electric power systems"; again I think both deserve
study, right now I believe solar thermal and PV systems are
comparable in price for terrestrial use, but perhaps larger
scale space systems would be quite different; I haven't
seen mass per kW numbers for the thermal approaches either, so
if you have references on that it would be useful.

Thanks for the comments!

Arthur