ESA GNC Conference Papers Repository

To limit the risk of cascading collisions, we will need active debris removal missions to retrieve satellites that die before they can be deorbited. It is well understood that sudden fatal failures can cause a dead satellite to tumble uncontrollably, but it also happens that even properly decommissioned satellites are not immune to spontaneous self-tumbling due to momentum buildup from solar radiation pressure torque, making removal much more challenging. The availability of a detumbling/antitumbling device ensuring passive stabilization of dead satellites could greatly reduce the risk and cost of debris removal missions. We present a totally passive magnetic damping device attached to a satellite's structure, where a rotor fitted with magnets is free to rotate inside a metallic housing. Even if the satellite is tumbling, the rotor stays aligned with the geomagnetic field: the differential angular rate between the rotor and the satellite will create eddy currents in the housing and thus dissipate rotational energy, eventually stopping the tumbling motion. Detailed sizing and simulation activities have demonstrated that one such small (h < Phi < 5cm diameter) and lightweight (m < 100 grams) device was capable of detumbling a medium-to-large satellite (5000 kg.m² of inertia) with a detumbling time constant of a few weeks. We present the current development status, including the results of vibration tests with two representative prototypes built around two competing technologies for the rotor bearing. These steps pave the way for the final development stages of a universally available detumbling function that can be a game-changer for reducing the future burden of taking care of defunct LEO satellites.