Concerning the ignition of a C12A7 electride plasma-based cathode

Hollow cathodes are crucial components for many electric propulsion systems used for space applications. However, they also represent a challenging and sometimes even limiting element for the propulsion systems. Particularly in recent times when alternative propellants are under evaluation for the thruster, and the design and the limits of the cathodes are being pushed. Consequently, significant improvement in the technology is desired. This publication tests a heaterless cathode using the emitter material C12A7 electride, particularly reviewing its ignition behavior and performance during an ignition cycling campaign. Stable heaterless ignition has been reliantly achieved in only a few milliseconds at an ignition potential of less than 400 V and 20 sccm Kr flow rate. Furthermore, two ignition cycling campaigns at different flow rates are presented, one reaching 3300 ignitions, the other igniting at only 6 sccm Kr flow rate. The degradation of the emitter materials and the influence on the ignition performance is discussed.