Japan’s Ministry of Economy, Trade and Industry plans to research an ambitious long term solar power project based on an orbiting satellite to be launched in the year 2040. Huge solar arrays 3 square km in area would collect enough solar radiation to allow the transmission of 1 GW of microwave energy back to earth. The two panel satellite would be assembled in geostationary orbit at an altitude of around 36 000 km, while the collecting stations will consist of 1 km diameter antennae located in desert regions or on the surface of the sea. The satellite is expected to weigh about 20 000 tonnes, and cost over 2000 billion yen to build. Power generation costs will be around 23 yen per kWh, more expensive than conventional generation, but the ministry expects costs to fall with advancing technology, and to trigger other technologies along the way. The ministry will draw up plans for the necessary research and development during the coming year.