Lifetime Prediction and Reliability Quantitative Evaluation of LaB₆ Hollow Cathode under Cathode Insert Depletion Failure Mode

With the wide application of electric propulsion technology in space missions, the life prediction and reliability evaluation of thrusters are particularly important. One of the key factors restricting the service life and reliability of electric thrusters is the service life of the hollow cathode, whose main failure modes are cathode insert depletion, structural failure of keeper, etc. Based on the insert depletion failure mode, an insert consumption model and lifetime prediction method under rated emission current are established. Comparing the consumption computed from the model with that from experiment, the rationality of the model is confirmed. Furthermore, hollow cathodes lifetime data under the insert depletion failure mode is attained by random sampling of the input parameters of the model within their respective uncertainty range in order to simulate several hollow cathodes working independently. Weibull distribution method is used to give the quantitative evaluation of hollow cathode reliability, and the influence of model sensitive parameters on the cathode’s lifetime is analyzed and discussed.