A Two-Gyro Semi-Passive Attitude Control System for Earth Pointing Satellites

摘要

The report is concerned with an earth-pointing satellite (in a circular orbit) making use of gravity gradient stabilization. A pair of gyros act as control elements by providing damping of attitude motion. The gyros are not torqued in any way; they are free to process relative to the satellite except for spring and viscous damper constraints applied to the gimbals. Attitude motion is damped by energy dissipation in the viscous medium as a result of relative motion between gimbals and satellite. Power must be supplied to drive the rotors of the gyros which are referred to as semi-passive control elements. The aim of the study was to investigate the possibility of using a pair of damper gyros to bring a satellite into an earth-pointing attitude from the angular rates which may exist at orbit injection, or which may be initiated as a result of meteoric impacts at a later stage of the satellite's life. It is found that for a particular design of a two-gyro damper, earth-pointing stabilization is achieved from an arbitrary initial attitude and a limited range of attitude rates. (Author)