Correcting my own math (was If only GEO we3e6 km in circumference)

I've corrected http://alglobus.net/NASAwork/papers/PathsToSpaceSettlement2011.pdf
(Paths to Space Settlement) wrt the number and size of PowerSats
needed to supply Earth's energy. Thanks to hitssquad for finding the
error. Although the error was much smaller than we thought at first,
it was still about a factor of 4 off. Please check the new numbers
but I think I got it right this time (NOTE: radius and 20% end-to-end
efficiency).

I do not think the spacing between sats needs to be nearly as large as
proposed. I don't know where the numbers came from, perhaps comsats.
SSP doesn't need to space like comsats because each is transmitting to
a different antenna so there is no interference. Thus, so long as the
sats don't run into each other (or anything else), its fine.

Also, particularly in the high numbers case, these sats will need some
propulsion for station keeping. Probably solar electric, there's
plenty of power! With a large customer base one can easily imagine
refueling sats that go from PowerSat to PowerSat refueling with
whatever the reaction mass is. Obviously, just another engineering
problem to solve. That's the fun part :-)

I also fixed the fraction of the Sun's energy that falls on Earth to
2.2 billion, thanks again to hitssquad for finding the error.

On Feb 1, 2012, at 2:26 AM, hitssquad wrote: