A novel concept for the active removal of large space debris is proposed exploiting the use of high-speed targeted ion beams coupled to electrodynamic tether systems. The Debris Shepherd (DS) is equipped with an electric propulsion system generating an ion beam pointed against the Space Debris (SD) to remotely modify its orbit and/or attitude without physical contact with the latter. We have named this method Reversed Electric Propulsion (REP).

In order to boost the system performance the DS is also equipped with an electrodynamic tether system (EDT) which provides, simultaneously, the power to feed the electric propulsion system and the thrust needed to neutralize the reaction of the targeted ion beam, hence keeping the distance between the DS and the SD bounded at all times.

Alternatively, a secondary propulsion system and an external power supply can be employed in place of the EDT for the price of a less reusable, yet more compact spacecraft, suitable for a first in-orbit demonstration of the concept. After introducing the space debris removal problem and its technological challenges we provide a description of the concept highlighting its technical feasibility, performance and reusability, based on simple physics, and the main technology milestones to bring it to maturity in a 15-year time frame. Finally we summarise the research milestones to be undertaken by our team for the present study.