Using Electromagnetic Drag on Tethers To De-Orbit Spacecraft

Two papers propose the use of electrically conductive tethers to remove spent or dysfunctional spacecraft from orbit around the Earth in order to reduce the hazard of orbital debris. In comparison with onboard rockets, these tethers would be more cost-effective, more reliable, and less massive. Once deployed, a tether would not require an onboard power supply. Both ends of the tether would be equipped with electrodes to make electrical contact with the ionosphere and thereby complete an electrical circuit. The orbital motion of the tether across the Earth's magnetic field would induce an electrical current in the tether. The consequent electrical heating of the tether would gradually dissipate the orbital kinetic energy of the spacecraft. It has been estimated that a typical spacecraft could be removed from orbit in weeks or months in this way, whereas the satellite might otherwise remain in orbit for years or even centuries.