Electrostatic Plasma Brake for Deorbiting a Satellite

Space debris in the form of abandoned satellites is a growing concern, especially at the heavily populated 600― 1000 km altitude orbits. To prevent new space junk from forming, new satellites should be equipped with a deorbiting mechanism. The problem is especially tricky for the emerging class of very small satellites for which using a braking rocket as a deorbit mechanism may have a prohibitively high relative cost impact. We describe a novel type of deorbiting mechanism that is suitable for small satellites with a mass of up to a few hundred kilograms. The method is a plasma brake device based on coulomb drag interaction between the ionospheric plasma and a negatively charged thin tether. The method resembles the well-known electrodynamic tether deorbit mechanism, but the underlying physical mechanism is different and the new method has an order of magnitude smaller mass and power consumption. The new method uses the same physical principle (coulomb drag) as the recently invented electric solar wind sail propulsion method. Furthermore, the tether required by the plasma brake is so thin that, if accidentally cut, the loose fragments of it pose no threat to other spacecraft and will rapidly descend into the atmosphere. The electrostatic plasma brake could enable an extended use of small satellites by resolving their associated space debris problem.