Hysteresis rods in the passive magnetic stabilization system for university micro and nano satellites

A passive magnetic attitude stabilization system is simple, easy to realize, cheap and does not require software development and energy consumption. Due to these features the passive magnetic attitude stabilization system is one of the most common attitude stabilization systems implemented on board of small satellites. This system is based on a permanent magnet, which has to provide a restoring torque to align an oriented axis of the satellite with the Earth's magnetic field direction, and a energy dissipation system of the satellite angular motion, which can consist on a set of magnetic hysteresis rods. Despite the simplicity of this attitude stabilization system, predicting performance in orbit and evaluating the obtainable accuracy is not trivial. The main problem is represented by necessity of an accurate modelling of the hysteresis rod magnetization and by the evaluation of the main magnetic parameters of the rods. This paper deals with sizing, choice of the material, manufacturing process, arrangement of a set of hysteresis rods on board small satellites and with the development of an experimental setup to measure hysteresis rod parameters. As an example the dynamics of the EduSAT microsatellite is investigated, by numerical simulations.