FOREWORD The Department of Energy (DOE) is considering several options for generating electrical power to meet future energy needs. The Satellite Power System (SPS), one of these options, would collect solar energy through a system of satellites in space and transfer this energy to earth. A Reference System has been described that would use photovoltaic cells to collect the solar energy, convert it to microwaves, and transmit the microwave energy via directive antennas to large receiving/rectifying antennas (rectennas) on earth. At the rectennas, the microwave energy would be converted into electricity. The potential societal impacts of constructing and operating the Satellite Power System have been assessed as a part of the Department of Energy’s SPS Concept Development and Evaluation Program. This is a report of that assessment. It has been preceded by Satellite Power System (SPS) Preliminary Societal Assessment, published in May 1979. The preliminary assessment summarized the results of fourteen individual studies of specific issues in four general areas: resources, institutions, international considerations, and public concerns. This report incorporates the earlier results and extends them on the basis of thirteen additional studies in the same general areas. It outlines the state of knowledge with respect to the issues addressed, delineates SPS-related problems and makes recommendations for further studies.