Hi All

Spectrolab has hit 40.7% efficiency with its terrestrial concentrator cells. And they're bullish about getting even higher conversion efficiencies. This is good news for PV Solar systems down here and good for PV systems in space.

Integrated inflatable concentrator/rectenna Solar Power Satellites could conceivably mass a mere 1120 tons tons for a 3 GW (in-space) or 1 - 2 GW (received on Earth) system. That's at 40.7%. Theoretically the multi-junction design can reach ~ 75% efficiency, reducing the mass to a mere 610 tons for a 3 GW in-space power-source. There's a lot of cool things that could be done with 3 GW of power in-space, like propelling 100 ton space-freighters to Mars in just 50 days with a Mag-Beam.

A souped up Ares booster should be able to put ~ 150 ton into LEO. Inflate a few collectors (individual units produce 300 KW in-space for just 24 kg mass) then tack on an ion-drive and you can boost it to L2 and assemble the SPS there in just ~ 5 launches. Sun-Earth L2 is ideal because the collectors always face the Sun AND the Earth.

Adam