Effective Attitude Control System for Small Satellite

Abstract

A Whale Ecology Observation Satellite (WEOS) was successfully launched on Dec. 14th 2002 as one of the piggyback payloads of H-IIA-4 launch vehicle. The functions of the attitude control system for the WEOS are de-tumbling and libration control by single axis magnetic torquer, and the earth pointing control by utilizing of gravity gradient torque. According to the resources limitation, the WEOS adopted the gravity gradient attitude stabilization system instead of the three axis attitude control system, as the first trial in Japan. The gravity gradient attitude stabilization system is working well as planned. This paper describes the attitude control system of WEOS and its control results.