Comprehensive modeling and characterization of Chang'E-4 radioisotope thermoelectric generator for lunar mission

Abstract

Radioisotope thermoelectric generator (RTG) is one of widely used power sources for deep space and celestial bodies explorations which has been developed for >60 years. The first RTG applied mission of China is the Chang'E-4 mission which was launched in December 2018 and operated on the far side of the moon till now, revealing its longevity, high reliability and adaptability. In this work, comprehensive thermoelectric model of the Chang'E-4 RTG was developed for the first time, and thermoelectric performance in laboratorial environment and lunar surface environment were investigated. The design parameters and working performance of the Chang'E-4 RTG were clarified, and the model which was built can help analyze the actual independent operating state and thermoelectric performance of Chang'E-4 RTG in any state and position on the lunar surface. The relative deviation of the calculated results of the RTG model from reported values is <4%. The simulation result in the lunar surface environment demonstrated that many factors may affect the performance of RTG on the lunar surface while the placement orientation of Chang'E-4 RTG would determine whether this RTG could work independently. A scheme that allows Chang'E-4 RTG to operate independently on the lunar surface is specified in the end.