As spaceborne energy-harvesting schemes go, this one seems faintly possible — an array of curved mirrors directing sunlight toward solar cells, their energy production microwaved down to Earth. It’s so realistic, actually, that NASA is providing funding for a proof-of-concept study.
A former NASA engineer named John Mankins, now with a company called Artemis Innovation Management Solutions, detailed his plans at a NASA innovation conference recently. The concept is called called Solar Power Satellite via Arbitrarily Large PHased Array (SPS-ALPHA), and it would harvest solar energy from a perch in high Earth orbit.
It would consist of a modular array of movable thin-film mirrors, which could be taken into space using current cargo ships and assembled piece by piece. This would be less expensive than building a gigantic array and launching it. These curved mirrors would redirect sunlight toward an internal collection of photovoltaic panels, and the solar energy would be converted into microwaves. Then the Earth-facing portion, or the bottom of the margarita glass in the image at top, would transmit low-frequency, low-intensity waves toward Earth. At the receiving end, power plants would convert the microwave energy into electricity, adding it to the power grid.