Magnetic components for the attitude control of space vehicles

Abstract

For attitude stabilization of earth satellites, frequently, magnetic systems are used. A main part of such systems are magnetic torquers that, together with the geomagnetic field, produce moments to control the attitude or angular velocity of the satellite. Magnetic torquers consist of permanent magnets or of coils. The coils may be air cored or iron cored. A compromise between permanent magnets and coils is given by chargeable magnets (semi-permanent magnets), i.e., coils with a core consisting of a material with high remanence and medium coercive force. To damp angular oscillations and to remove spin rates, permeable rods are used which undergo magnetization changes in the geomagnetic field, thus transforming the kinetic energy of the satellite into hysteresis and eddy-current losses. Other damping devices consist of a secondary mass dissipating energy by moving relative to the satellite. Extensive testing is necessary to assure proper functioning and reliability of the devices described.