Overview of the activities for space solar power systems in USEF

The Institute for Unmanned Space Experiment Free Flyer (USEF) has been studying wireless power transmission under the contract of the Ministry of Economy, Trade and Industry (METI) from 2004 to 2005. In this study, we have focused on the microwave power transmission on the ground as a key technology for the realization of a future space solar power system. (i) A prototype active phased array panel with software retro-directive beam steering antenna and hardware retro-directive antenna had been manufactured and evaluated. In 2004, a combination test with these two active phased array systems with different beam steering systems was performed. The purpose of the test was the demonstration of the basic phase synthetic characteristics and beam steering scheme. The test results indicate an appropriate result for the basis of the future hybrid beam steering system. (ii) An investigation of the microwave power system for the ground application was also performed. Three types of this system have been proposed. (iii) The environmental and safety assessment of microwave power transmission is also the theme of this current investigation. This assessment has been performed to permit the acquisition of public acceptance for a future microwave power transmission system. The results of this study together with our past activities such as an SSPS system study are presented in this paper. © 2006 Lister Science. All rights reserved.