Thermal control analysis and conceptual design of a hybrid power subsystem for a lunar rover operating at the south pole

The exploration of the south pole of the moon and its surface has emerged as a top priority for numerous space agencies, driven by its scientific and strategic significance. Rovers play a crucial role in lunar exploration, providing the necessary mobility to navigate and conduct experiments across the lunar terrain. One of the key challenges faced by lunar rovers is the dynamic thermal environment, fluctuating between extreme temperatures from day to night and transitioning between illuminated and shaded regions. In particular, realistic south pole illumination conditions include intermittent shadowing caused by horizon-induced solar occultations, where the efficient operation of the Electrical Power Subsystem (EPS) is critical for reaching a successful mission. This study belongs to a project funded by ESA called “Power management conditioning for hybrid radioisotope-solar power systems (AMPERS)”, and it focuses on the conceptual thermal design and thermal control strategies for a hybrid EPS, incorporating solar panels, batteries, and a Radioisotope Thermoelectric Generator (RTG). This hybrid configuration ensures a reliable and continuous power supply to the rover under diverse lunar scenarios. Thermal analyses are conducted in ESATAN, enabling an accurate radiative calculation of the lunar environment and the rover. Subsequently, a model is developed in EcoSimpro to examine the fully coupled static and dynamic thermo-electrical behaviourof the hybrid EPS. Finally, a thermal control concept is proposed in which the RTG is not treated solely as a power source but is actively integrated into the rover thermal control architecture, while the hybrid EPS ensures continuous electrical power throughout the mission under different thermal scenarios.