Fast Turn-On Thrusters for Space Debris Removal

A promising approach to space debris removal is the use of SmallSats to detect, intercept, capture and slow objects in orbit. These satellites must be highly maneuverable and responsive. They must have propulsion systems that have long life and high power and yet are not encumbered by excessive weight or size. They must have great dynamic range to allow them to rapidly respond when debris is detected. Ion propulsion is the most economical and practical approach to this end. Both Hall and Ion Thrusters will be considered. The most critical performance limiting element in these thrusters are the discharge cathodes that provide the electrons for ionization of the inert gas that is fed into the ionization chamber. This proposal offers three state-of-the-art cathodes which will provide the quick response times, fast turn-on and long life (15 years) that are needed for this purpose. The cathodes are planar scandate, ternary alloy, and planar reservoir. Further, it offers a new cathode geometry that supersedes present hollow cathode art. The new geometry allows thrusters to have turn-on times as little as 8 seconds.