FEL powering of satellites: a technically and economically viable program

Beaming of laser energy through the atmosphere is a means of supplying electrical power to orbiting satellites. By using a new ground based free electron laser developed by Lawrence Berkeley National Laboratory many times the amount of electrical power can be generated by the satellite from the same area of array now used for solar power. There is currently a shortage of power in space, and the demand is rising exponentially. Satellites which appear from earth to remain fixed at one point in the sky are said to be in geosynchronous orbit (GEO). They are used to relay long distance telephone communications, television, e-mail, credit card checks from the local gas pump and a myriad of other applications. In addition to the shortage in power there is also a shortage of available bandwidth. In response to that problem a higher frequency band, the Ka band, is being opened for satellites and fifty companies in the United States are planning to launch satellites which use it. Unfortunately rainfade is a serious problem at this frequency and ten times the usual power is sometimes needed to overcome the effects of rain. Laser power beaming is an answer to this problem. Key elements are a powerful 200 kW free electron laser and a fully compensated 11-meter diameter adaptive optics projection telescope. Remarkable progress has been made on both these ambitious objectives in the last two years.