Power/energy: Solar Power Satellite ground stations: The ground systems for microwave beaming from the SPS would require a rectifying antenna with over 13 billion elements

Picture a low-gain rectifying antenna that is about 10 km in diameter, consists of 13 billion elements and has seven billion rectifiers. Add a medium-voltage dc power-collecting grid, dc/ac converters, and a high-voltage ac power-collecting grid. What you have roughly is the main ground installation for the Solar Power Satellite (SPS) system, and its immensity is almost overpowering. Yet studies done for the National Aeronautics and Space Administration and the Federal Department of Energy indicate that the size and complexity of the equipment are not beyond present capabilities for production and construction.