Describe a beamed power solution. ( Digest Number 135)

>
> FYI, there's a SPS discussion taking place right now on the Usenet
> newsgroup sci.space.policy. Geoffrey Landis, who has done actual SPS
> work, just got through saying that there have been proposals for
> orbital power relays, but that they turn out to be not that much less
> complicated than full-up SPS.
>

Well, yes, I saw that quote.

I know Geoff Landis quite well, we both worked at NASA Lewis for a
while, and we socialized quite a lot. He certainly knows space power
well, and from time to time we share iformation.

Geoff was commenting on microwave relay via the RF-DC-RF conversion.
Note that he did not quote any numbers, and simply saying "not much
less" is rather vague.

An SPS relay satellite will cost less than a full SPS. By how much is
not an easy question to answer. At the very least it removes the PV
solar array, which is the heaviest part of the system, over 50% of the
spacecraft weight, so will undoubtedly make a singificant dent in the
launch cost. Sorry, I do not have any numbers either.

But reflecting RF is a very different matter, and can be a lot cheaper
then either SPS or relay.

Note that I think the path length problem can be resolved by using a
curved reflector which re-concentrates the beam somewhat.

CR.