Control Technologies Required for Electrodynamic Tethers and Active Debris Removal

The amount of space debris has been increasing, and some evolutionary models predict that it would increase even if new satellite launches were stopped because of mutual collisions between existing objects. In such a case, debris mitigation measures such as explosion prevention and end-of-mission de-orbit will be inadequate and an active debris removal (ADR) will be needed to preserve the space environment. JAXA is therefore studying an active removal system that can rendezvous with and capture non-cooperative debris objects to transfer them to a lower orbit for disposal. The propellant requirements of conventional propulsion systems make them infeasible for transferring multiple objects, and instead the electrodynamic tether (EDT) is considered to be one of the most promising propulsion systems for de-orbiting debris in low earth orbit (LEO). As a first step towards realizing an ADR, preparations are underway for an EDT flight experiment. This paper describes the control technologies required for the EDT and ADR.