Present and Future Aspects of Japanese CS Program

Japan's CS spacecraft was launched successfully in December 1977 and positioned at 135 deg east longitude in a geostationary orbit. After an initial on-orbit performance checkout, substantial communication and operation experiments were conducted starting in May 1978 as scheduled. Spacecraft attiude and position are being maintained precisely, and onboard mission equipment including the despun antenna and C-band (6 GHz/4 GHz) and K-band (30 GHz/20 GHz) transponders are working well except for two K-band transponders that had been excluded from the objectives of the experiments due to malfunctions that had occurred during the checkout period. After one year of experiments, it is concluded that the present CS-like system would be suitable for a future operational domestic satellite system in Japan.