A spacecraft attitude stabilization system with low-power magnetic torquers

This paper describes a spacecraft attitude stabilization system that uses a set of 12 low-power magnetic torquers. The low-power magnetic torquer consists of a hard magnetic-material rod inside a solenoid. Discharging a capacitor through the solenoid winding generates a current pulse that changes the magnetic dipole moment of the rod when required. The interaction of this magnetic dipole moment with the Earth's magnetic field creates a torque on the rod that can stabilize the attitude of a spacecraft in a low Earth orbit. Computer simulation results show that a system of 12 low-power magnetic torquers with a combined mass of 3.5 kg or about 8 lb can stabilize a 1400 kg or 3000 lb spacecraft in a 600 km circular orbit to a local vertical orientation in five to ten orbits. With initial rates of 1 deg/s or less in each axis, the peak power dissipated in the low-power magnetic torquers is 440 mW or less, the average power prior to settling is 125 mW or less and the average power after settling is about 2 mW or less.