Photo courtesy SPS-ALPHA/http://www.nasa.gov/pdf/716070main_Mankins_2011_PhI_SPS_Alpha.pdf
Twenty-two thousand miles above the Earth, an array of silicon glitters in the sunlight, quietly beaming power down to the planet below and providing energy to millions. One-hundred million miles away, a single photon leaves the sun, rocketing at the speed of light towards Earth. Upon arrival, the photon hits the silicon array of the solar cells in geosynchronous orbit, where the cell transforms the raw energy of the sun into microwaves, which are beamed down to a receiving station on Earth. Once at the receiving station, this power is fed onto the electric grid where it can now be used to power cities and homes. Behold, the possibilities of space-based solar power.