Influence of heating mode on life reliability of a hollow cathode heater

The electric propulsion hollow cathode is a thermal electron emission device that can be used as an electron source and a neutralizer for aerospace electric propulsion systems. As a serial structure, the cathode's life reliability is the key to its application in orbit. The heater is used to start the hollow cathode, and short-circuit and open-circuit failure are important forms of hollow cathode failure. Herein, we compare multiple groups of constant voltage power supply mode (U mode) and traditional constant current power supply mode (I mode) for the same structural heater, and reliability analysis is performed using two-parameter Weibull distribution. The results show that under the constant voltage power supply mode, there is a negative feedback mechanism that increases the resistance of the heater, and the overall heating power decreases. This extends the heater's lifetime and reduces dispersion of resistance variations, leading to a substantial increase in the lifetime reliability of the heater in the constant voltage mode. Finally, we propose a current limiting method that starts when the constant voltage power supply is applied and solves the problem of excessive current surge when the heater starts.