Characterization of Lunar Thermal Environments: Regional and Terrain Effects on Sink Temperature

Accurate thermal environment characterization of the Lunar surface requires details of the mission-specific location including maximum incident solar elevation angle, terrain features, and regional regolith thermophysical and optical properties. Particularly for polar regions, a universal and generic thermal model that captures worst case hot and cold conditions does not exist, in part due to limitations in satellite derived surface temperature data resolution. This study presents and compares environmental sink temperature results obtained from thermal models assuming a flat surface ground plane for polar, mid-latitude, and equatorial regions. Results from the polar model assuming a flat ground plane as a stand in for the Lunar surface are compared with those obtained from a model with site-specific detailed Lunar terrain. Discrepancies are noted between the simplified flat plane and detailed terrain models, particularly in the South Pole region where low solar elevation angles and surrounding terrain features substantially impact thermal conditions. Additionally, an overview of the LUnar and Mars ENvironments Analysis Team (LUMENATE) is provided. Examples of LUMENATE work products related to this study include thermal insights for an agency Lunar cold tolerant electronics report and the development of a detailed terrain modeling processes used for assessment of Artemis III Human Landing System (HLS) extravehicular activities (EVAs).