Cusp-type bi-directional radiofrequency plasma thruster toward contactless active space debris removal.

Active removal of space debris is an emerging technology aimed at sustaining space activity in Earth orbit by mitigating the risk of collisions between operational satellites and debris. Utilizing a bi-directional magnetic nozzle (MN) radiofrequency (rf) plasma thruster has been proposed to remediate and remove debris from the Earth orbit, where the debris is decelerated by continuously exerting a force to the debris by a plasma beam ejected from the thruster, and zero net force exerted to the thruster is simultaneously maintained by ejecting a second plasma beam to the opposite direction, maintaining the distance between the satellite and the debris. Previous laboratory experiment has demonstrated bi-directional plasma ejection from a single MN rf plasma thruster having two open source exits for symmetric magnetic field configuration having fairly straight magnetic field lines in the insulator source tube wound by a rf loop antenna. Enhancing the force exerted on the debris is essential for reducing the time required for deorbiting. Here it is demonstrated that a symmetric cusp-field configuration can increase the force exerted to the debris under the circumstance that the thrust is maintained at nearly zero level by the bi-directional ejection of the plasma, where the convergent-divergent MNs are formed near the two open-source exits.