Rapidly Starting Cathode for Electric Propulsion

"Busek's tandem Hall thruster can deliver precisely controllable, repetitive or single impulse bits of arbitrary magnitude, the latter dictated by the duration of the discharge pulse. To fully capitalize on the pulsed operation of a Hall thruster requiresa cathode capable of rapid starting to minimize the time from the command for thrust to the time the discharge pulse can be initiated. The most significant delay occurs during the time required to heat the cathode emitter and the time to establishexpellant within the cathode.In the Phase I program Busek will evaluate several methods and approaches to rapidly starting an electron source for the thruster. Approaches to be analytically and experimentally characterized include a derivative of our standard hollow cathode designedfor rapid heating of the emitter insert and novel approaches for heaterless style cathodes.Proof of concept and preliminary experiments will be conducted to determine methods for rapid starting and characteristic turn-on times. The most promising approaches will be further investigated for thermal and discharge cycle capability.In Phase II prototype cathodes will be designed and fabricated for integrated testing with a Hall thruster in the pulsed and steady state operating modes. Busek's low power propulsion system can fulfill all the propulsion requirements of missions requiring orbit raising, repositioning and close proximity formation flying. A rapidly star