1. a Advanced Mechanical Systems Department, Central Research Laboratory, Mitsubishi Electric Corporation, 8-1-1 Tsukaguchi-Honmachi, Amagasaki, Hyogo 661, Japan
2. b Advanced Mechanical Systems Department, Central Research Laboratory, Mitsubishi Electric Corporation, 8-1-1 Tsukaguchi-Honmachi, Amagasaki, Hyogo 661, Japan
3. c Communication Satellite Systems Department, Kamakura Works, Mitsubishi Electric Corporation, 325 Kamimachiya, Kamakura, Kanagawa 247, Japan