Spacecraft:
The JERS-1 spacecraft, built by Mitsubishi Electric Co. as prime contractor, consists of a net rectangular bus (0.9 m x 1.8 m x 3.2 m) with a single 2 kW solar array (3.5 m x 7.0 m) and an eight-segmented SAR antenna. The spacecraft is three-axis stabilized with zero momentum bias system using reaction wheels and magnetotorquers. The attitude is sensed by an Earth sensor, an inertial reference unit and two sun sensors (0.3º attitude knowledge). A hydrazine propulsion system is used for orbit maintenance. Nominal mission design life = 2 years. Satellite mass = 1400 kg at launch