The solar power satellite concept - The past decade and the next decade

Results of studies on the solar power satellite concept, currently under evaluation by NASA and the Department of Energy, are summarized. The basic advantages provided by the concept are the near-continuous access to sunlight and the freedom from atmospheric effects and cloud cover. The systems definition studies have considered photovoltaic and thermal energy conversion systems and found both to be technically feasible, with the photovoltaic approach being currently preferred. A microwave test program is under way which will provide quantitative data on critical parameters, including beam forming and steering accuracy. Ballistic and winged launch vehicles have been defined for the transportation of construction materials, with the Shuttle expected to provide low-cost transportation to and from space. A reference system has been outlined for evaluating the concept in terms of environmental and other considerations. Preliminary estimates of natural resource requirements and energy payback intervals are encouraging.