Optimal geometry and materials for nanospacecraft magnetic damping systems

Abstract

A magnetic damping system for nanospacecraft attitude stabilization is proposed, based on the use of thin strips of amorphous Fe-B-Si soft magnetic ribbons. The size, number, and location of the strips is optimized, and a predictive formulation is provided. The main result of ground tests, comparing the performance of several soft magnetic materials, is that suitably heat-treated amorphous ribbons provide the best loss performance in the whole range of magnetic fields expected in orbit.

Volume magnetization for system-level testing of magnetic materials within small satellites

“…Here there is a significant degradation in dampening ability when the rod separation is less than 30% to 40% of the rod length (each rod is 9.5 cm), which is in agreement with a general PMAC heuristic [30]. This measurement is also in good agreement with Figure 9 of [27], which shows that groupings of thin 100 mm length hysteresis strips have an exponentially increasing global demagnetization factor when grouped closer than 40 mm together.…”

“…The use of an excitation (magnetizing) & sense (or pickup) coil is an accepted method of hysteresis measurement [21]. Recent empirical testing of hysteresis rods for PMAC systems have been performed by two main groups: Ivanov et al [25] (also [26]) use a small excitation solenoid (only magnetizing one hysteresis rod), while Santoni et al [27] (also [28], [29]) use a larger excitation solenoid capable of magnetizing a large array of rods. We present a method of using the Helmholtz cage itself as the excitation coil, as it is able to supply a uniform magnetizing field in a large volume and in any direction.…”