What are Solar Power Satellites?
Solar power satellites as envisioned are large-scale power plants based in space in geosynchronous orbit. The satellites would be in the sunlight for over 99% of the year. They would only pass through the shadow of the earth for brief periods during the spring and fall equinoxes. Electric energy would be generated by vast arrays of solar cells converting sunlight to electricity. The electricity would be routed to a phased array transmitting antenna that would convert the electricity into radio frequency energy and transmit the energy in a wireless power transmission beam to an earth-based receiver. This receiver, called a rectenna, would convert the radio frequency back into DC electricity. Power processors would then convert the DC electricity to AC power for distribution on existing power grids. The power output of each satellite studied during the System Definition Studies was 5 gigawatts (about equivalent to the output of Grand Coulee Dam). Smaller satellites are possible. However,
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Solar Power Satellites (SPS) are fairly large structures in space that convert solar energy, captured as solar irradiation, into an energy form that can be transmitted wirelessly (Wireless Power Transmission – WPT) to any remote location with a receiver station, either on Earth, to high altitude platforms, to other spacecraft or even to surfaces of the moon or other planets. This idea has a long history, for an overview see this table. Why go into space instead of building them on Earth? The big advantage of space based solar power collection is the 24h availability: unlike the situation on the surface of Earth, in geostationary orbit there is no night and the sun is never shadowed by clouds, rain or fog. Since we are using energy day and night, the continuous power generation in space makes large and expensive energy storage devices superficial. But the final trade-off depends on many more parameters that are subject of the study started by the Advanced Concepts Team. How is the power
Solar power satellites are a hypothetical future technology that could provide abundant free energy to the people of Earth. The concept involves placing large (50-100 km2) solar panels in high earth orbit to gather sunlight there and beam it down to a rectenna on the Earth, from which it can be distributed and used. Since the shadow of the Earth would rarely obscure the sun from such satellites, and are located outside of out photon-blocking atmosphere, a given square kilometer of solar panel in space would gather about 5 times more power than a panel exploiting the same area on Earth. According to calculations performed thus far, it is estimated that solar satellites would provide about a gigawatt of power per 10 square kilometers (3.86 square miles) of panel. The availability of nuclear power makes it dubious that solar satellites will ever really be necessary, but the concept is still interesting for consideration. Thinking about such concepts helps us get creative when it comes to
