Trade-Off Analysis for Attitude Control in Highly Elliptical Orbits

Three-axis attitude stabilization of a satellite using only magnetorquers as actuators defines an underactuated control system problem. This is due to the fact that the magnetic torque is always orthogonal to the magnetic field vector. There are Low Earth Orbits where the magnetic field has enough variation to prove three-axis stabilization on average. We evaluate this type of control for Highly Elliptical Orbits as a preliminary low-cost alternative for inertial attitude pointing. Nonetheless, we show that this solution is not robust under environmental perturbations and limits the practical application of the magnetic control for high altitudes. We conclude with the combination of reaction wheels and magnetorquers, using the latter to unload wheel's momentum on perigee passages.