抄録
A Whale Ecology Observation Satellite (WEOS) was successfully launched on December 14th, 2002. We adopted a single-axis magnetic torquer damping control and gravity gradient attitude stabilization for WEOS. It is the first trial in Japan for pointing communications antennas towards Earth, and the GPS antenna towards zenith. The damping control and attitude stabilization system of WEOS consists of a three-axis magnetometer, a magnetic torquer coil, a deployable mast with a fixed mass at the tip, and attitude control software. This system carried out rate damping control of the principal axis of the maximum moment of inertia and earth pointing attitude stabilization. Immediately after separation from the H-IIA-4 launch vehicle, WEOS tumbled due to the imbalance force of the three separation springs. The tumbling was reduced by the closed-loop damping control and then the mast was deployed. After 1 week, we confirmed the establishment of the gravity gradient attitude stabilization. This paper describes the attitude control system, operation procedure, and control results.
