Electrodynamic Technologies: unique solutions to space debris collection Electrodynamic Technologies

Propellantless Orbit Maintenance

The orbit of the International Space Station is constantly being lowered by the air drag. It takes multiple reboosts every year to maintain the average altitude of the orbit. In addition, the station has to perform maneuvers to avoid close encounters with assorted debris objects. This orbit maintenance requires constant supply of fuel. Future space stations will face the same problem, but there is another solution.

In the late 90s, the orbit of the Mir station was deteriorating because there were not enough resupply flights bringing fuel necessary to maintain the altitude of the station, and it was proposed to use electrodynamic propulsion instead. In 1999-2000, Tether Applications, Inc. designed and built the Mir Electrodynamic Tether System (METS), and Dr. Levin of Electrodynamic Technologies, LLC, provided dynamic analysis and flight control algorithms. The tether consisted of a 6-km insulated wire, 1-km bare aluminum tape for electron collection, and a 0.5-km pilot tether. A spare 200-kg Manned Maneuvering Unit was to be attached in orbit as a counterweight. The system was designed to draw 2 kW of power from Mir and produce 0.2 N of average thrust along track to keep Mir in orbit without fuel re-supply, allowing the newly formed MirCorp to open Mir to commercial space tourists. METS was not tested in orbit because of the decision to deorbit Mir, but this technology is directly applicable to the orbit maintenance of other space stations.