Hollow Cathodes Development for Alternative Propellants Electric Propulsion Systems

The development of discharge cathodes has a long history at University of Pisa, starting from dedicated cathodes for MPD thrusters, and moving to laboratory prototype Hall thrusters and up to flight models. In recent years, the Electric Propulsion group focused on the development of hollow cathodes capable to operate with different propellant other than xenon, for specifically founded project. First, a high current (up to 100 A) xenon-krypton hollow cathode is under development as electron source for the dual-channel Hall thruster funded by the TANDEM project. Then, an iodine cathode, capable to deliver 1-3 A of discharge current, is under investigation as main electron provider for low power iodine electric propulsion systems. Finally, an hydrogen cathode has been built and tested as a plasma source for a neutral generator for fusion applications. This paper describes the design phase and the current status of each of these cathodes at UniPi.