Conceptual study of SSPS demonstration experiment

An SSPS (Space Solar Power System) study team was organized under the USEF/METI (Institute for Unmanned Space Experiment Free Flyer/Ministry of Economy, Trade, and Industry) committee on SSPS technologies for practical use. The study team, composed of researchers from universities and national laboratories, has made a conceptual study of a demonstration experiment, planned for the near future, to verify the essential technologies for SSPS. The basic plan is to place a satellite in low Earth orbit to demonstrate microwave power transmission to the ground. The satellite has a 16 m × 17.6 m plate consisting of 400 power-generation/ transmission modules and an end mass, which are connected with a truss and tether wires. The attitude is stabilized by the gravity-gradient force so that the transmitting antennas in the lower panel are always directed toward the ground. The experiment will be able to demonstrate microwave power transmission of more than 100 kW from orbit to the ground target. The study team has also led the development and testing of the microwave circuits for phase control and power amplification, which are critical for the demonstration experiment.