Thermal Analysis and preliminary Thermal Control System design for a LuNaDrone mission to the Lunar South Pole

In recent years, lunar exploration has garnered increasing international interest, driving the development of innovative technologies aimed at supporting sustainable surface missions. Evolunar, a deep-tech spin-off of Politecnico di Torino incubated in the ESA BIC Turin programme, is contributing to this vision through the LuNaDrone project, an autonomous flying vehicle designed to operate in extreme lunar environments. The unique mobility of LuNaDrone provides a strategic advantage for accessing challenging locations, such as lunar pits and permanently shadowed regions, and for acquiring valuable scientific and mission-critical data to enhance resource identification, hazard detection, cooperative exploration, logistical operations, and the development of future lunar infrastructure. This thesis focuses on the thermal analysis and development of a preliminary thermal control system (TCS) for LuNaDrone, with particular emphasis on the environmental conditions at the lunar south pole. Following a comprehensive review of the state of the art in thermal control strategies for small spacecraft and regulations related to thermal analysis, a thermal model of the lunar surface at mid-latitudes was developed based on previous studies. This model was subsequently extended to represent the thermal conditions at the lunar south pole, a region of high scientific interest as highlighted by the focus of the Artemis program, and which is characterised by extreme temperature variations, reduced solar radiation incidence, and a resulting highly heterogeneous thermal environment. The model was validated against Diviner data from NASA’s Lunar Reconnaissance Orbiter to ensure its accuracy in reproducing realistic lunar surface conditions. A crucial aspect of this work involved the thermal characterisation of the thrusters selected for LuNaDrone. A dedicated thermal model of the propulsion system’s thrusters was developed and validated using data provided by the thruster supplier. This model was then integrated into the overall thermal model of the drone, enabling a more comprehensive assessment of its thermal behaviour. A key contribution of this thesis is the development of a complete thermal model of LuNaDrone, which was carried out by analysing and representing the main subsystems. For each component, thermo-optical and thermo-physical properties were evaluated to achieve the most accurate representation of the system, aligned with project’s phase of development. This model was then employed to perform thermal analysis of the drone in the lunar south pole environment, allowing for the identification of critical thermal issues of the system. The thermal analyses were conducted using the Ansys Thermal Desktop Heat Transfer & Fluid Flow Modeling Software, ensuring a robust numerical approach to modelling the spacecraft’s thermal behaviour. These analyses were performed in accordance with the operational scenarios proposed by Evolunar for the mission, ensuring that all relevant thermal constraints and conditions were considered. Following the identification of critical thermal issues in the drone’s operation within the lunar environment, the simulation results guided the development of a preliminary thermal control system designed to ensure operability under the extreme conditions of the lunar surface.