On Oct 2, 7:29 am, John Schilling wrote:

That's almost entirely a question of scale. Solar Power Satellites
can be built and will work as advertised, it's just that if you read
the fine print in the advertisements, the things only work well at
power levels of several gigawatts or so. Anything less, and you run
into problems with the relative size of the antennas for power beaming
from desirable orbits. Or, alternately, the seriously inconvenient
duty cycle and load sharing problems associated with the crappy orbits
you're limited to with small antennas.

Well, that answers my next question: why, if an SPS works, does it
have to be so big? Many thanks.