utility integration requirements because financial risks and lead times will vary for state and local participants. However, barriers to utility participation can be removed by appropriate institutional arrangements and coordination. In general, once higher order problems are solved (e.g., system costs compared to alternatives and availability of rectenna sites) institutional and regulatory problems should be more amenable to solution since risks and lead times will have been reduced or at least clarified. International Issues International issues confronting SPS development present a complex array of problems requiring significantly more research as well as coordination with other international entities whose inputs are critical. There will be a need for new international treaties, particularly with regard to orbital slot assignments and ensuring the peaceful use of SPS. Since an international organization is strongly indicated for SPS development and commercialization, it is incumbent upon the U.S. to fully understand the stakes which international actors would have in any multinational SPS program. The precise level of international participation must still be weighed in terms of a timely response to U.S. energy needs. To make these judgements will require knowledge of: (1) who potential participants would be; (2) what their interest in an SPS program would be; and (3) how U.S. and foreign interests would mesh. Public Concerns It is necessary to involve the public in SPS decision making and to respond to public concerns. In the Societal Assessment a mechanism for exploring the ways and means of involving the public, the Public Outreach Experiment, was implemented. Future studies of public concerns should utilize an outreach mechanism in broadened form to reach a larger representation of public interests.4 The results of public acceptability studies suggest that public acceptance of SPS will not be easily obtained. There are elements of the SPS system which are the basis for both opposition and support from the public, and it is possible that controversy and conflict among different public sectors indicative of competing values and perceptions of the SPS system may result.