Small lunar rovers face tight thermal constraints because their low mass and limited power leave little margin for heaters or radiators. The HAKUTO team developed a thermal control strategy for the flight model, using an analytical model that divided the rover into six radiating surfaces.
The model accounted for solar radiative flux, lunar radiation, solar albedo, and conduction from the regolith, with surface temperatures depending on rover orientation. From this, the researchers selected mounting locations for avionics and the angle of solar panels to optimize both thermal performance and power generation while keeping mass under 4 kg.
After preliminary analysis, numerical simulations refined the thermal response of the final design. The team then verified the model through a thermal balance test in a vacuum environment, matching the flight conditions.