[AR] Re: space based solar
- From: John Schilling <john.schilling@xxxxxxxxxxxxxx>
- To: arocket@xxxxxxxxxxxxx
- Date: Wed, 20 Mar 2019 20:54:11 -0700
On 3/20/2019 10:07 AM, Henry Spencer wrote:
Powersats unfortunately have a bad scaling law for power lines: power
output scales with the square of size, while if you want to keep the
line-loss percentage the same, line mass scales with the fourth power
of powersat size. (If you double the powersat size while keeping the
design otherwise the same, each line has to carry four times as much
current, so it needs four times the cross section to keep a constant
loss per unit length. But the line is also twice as long, so it needs
*another* factor of two in cross section to hold end-to-end loss
percentage constant. And twice the length adds yet another factor of
two in mass.)
What are these "lines" of which you speak - aren't we just going to use
microwave power beaming for everything?
OK, that was meant as a joke, but maybe it isn't. I'm trying to
envision a "Powerswarm" where the one big transmit antenna is surrounded
by a swarm of mini-powersats using intra-swarm microwave links over a
few kilometers, each energizing a single element of the big phased array
so we don't ever have to run power through more than a few meters of
wire. The constellation orbital dynamics will be tricky, but with
fluffy solar collectors exchanging microwave photons we can maybe go a
little bit non-Keplerian using radiation pressure.
Gaah. It's too late at night for that much math.
John Schilling
john.schilling@xxxxxxxxxxxxxx
(661) 718-0955
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