Ion beam shepherd satellite for space debris removal

A novel contactless space debris removal system is proposed in which the debris orbital motion is actively controlled by exploiting the momentum transmitted by a collimated beam of quasi-neutral plasma impinging against its surface. The beam can be generated with state-of-the-art ion engines from a "shepherd spacecraft" coorbiting nearby. This space- craft, placed at a distance of 10?20 m from the object, would use a state-of-the-art ion thruster pointed towards the debris, as well as a sec- ond propulsion system to compensate for the beam reaction in order to keep a constant distance between the debris and the shepherd satellite throughout the deorbiting process. The key aspects of the concept, in- cluding the propulsion requirements, the modeling of the plasma beam, the momentum transfer to the body, and the dynamics and control of the system, are discussed