Solar Power Satellites

>
> > We could slowly rotate the entire STEG, ISRCCs and
> > all. It would also probably require rotating the
> > entire SSPS, and having a method detached from the
> > SSPS to steer the Microwave beam?
>
> It's a tempting idea, but the problem with rotating the SSPS is that you
> will then have gyroscopic forces which will make it difficult to steer
> the array. And solar-concentrating SPS have more rigorous pointing
> requirements than do flat PV arrays.
>
This is true, but offsetting the difficulties of associated with
positioning is that a solar concentrating SPS will be using a rankine
cycle for the generation of electricity. This is still the most
efficient method of producing electricity. The average PV array is
less than 10% efficient, while a rankine cycle can be up to 40%
efficient with most running at 35% efficiency.

Before you dismiss solar concentrating you need to ask several questions:
1) is it cost effective?
2) is the mass of PV array significantly (>300%) less than an
equivilent rankine cycle system?
3) Are PV arrays more reliable? What is the cost assocaited with repair?
4) What are the functional requirements? Do you need personel in space
for both, one or the other?

There are probably more questions to ask.

Bill