Solar Power Satellite

A solar power satellite (SPS) is a large spacecraft placed in Earth orbit — typically geostationary orbit at approximately 35,786 km altitude — equipped with extensive photovoltaic panels or solar concentrators to collect sunlight and convert it to electrical power. That power is then converted to microwave or laser radiation for wireless transmission to a ground-based receiving station. The SPS concept was first formally described by Peter Glaser in 1968 and was the subject of a major 1979 NASA/DOE Reference System Study. The term is often used interchangeably with space-based solar power, though technically an SPS is one component of the broader SBSP system. No full-scale SPS has been built or deployed. Demonstrators at small scale have been tested, including JAXA ground demonstrations and the Caltech MAPLE orbital experiment in 2023.