Microwave power: a 'far-out' system?

Prospects of satellite power stations beaming energy to earthbound antennas seem brighter than ever. A key new concept, provided by Gerard K. O'Neill and his staff at Princeton University, is that the satellite stations could be manufactured from raw materials mined on the moon. That approach can overcome one of the most overwhelming obstacles to the practical realization of the stations: the immense launch costs involved-an estimated $80 billion dollars for an 8000-MW station-if all station equipment is manufactured on the earth and then shuttled into orbit at present-day equipment and launch costs. O'Neill's proposal takes advantage of the moon's low-gravity and vacuum environment, which permits continuous electromagnetic launching of lunar ores at less than 5 percent of the energy required for lift-off of comparable payloads from earth. The lunar ores would be processed with solar energy into structural materials for satellite solar power station (SSPS) mass production at space-manufacturing facilities that would be constructed near the moon's orbit. The SSPSs would then be deployed from the colonies to a geosynchronous orbit 35800 km from earth.