When the orbital altitude of a satellite is relatively low, the methods of magnetic and aerodynamic stabilization can be considered. Both methods are very effective when the satellite is small. In particular, magnetic and aerodynamic stabilization systems have been installed in some satellites. Examples are UO-sat and Cosmos-320 with magnetic and aerodynamic methods respectively.
Magnetic torques acting on a spacecraft result from the interaction of the spacecraft's residual magnetic field and the geomagnetic field. Because a magnetic torque is always orthogonal to geomagnetic field vector, it is not favorable in all regions of the orbit. The aerodynamic restoring torque can be provided by a very light tail stabilizer which is several meters downstream from the main body of the small satellite. The gravity gradient stabilization method also has been used in many satellites. One of the examples is the Eole satellite, In the recent years, many small satellites have adopted this method owing to its long life and continuous Earth pointing characteristics.
The purpose of this paper is to compare the methods of magnetic and aerodynamic stabilization both based on the aid of a gravity gradient boom for attitude control. We shall consider the attitude motion of a 50 kg microsatellite and the set of nonlinear equations of motion will be solved numerically with specified initial condition. The satellite operates in a circular orbit with 500 km altitude. The history of the attitude stabilization will be investigated and discussed in detail.