Enhanced Topography Models for Selected Lunar South Pole Regions with Shape-from-Shading

Abstract High-resolution digital elevation models (DEMs) are an important resource both for lunar science and for human and robotic exploration. Photoclinometry, or Shape-from-Shading (SfS), is particularly well adapted to producing highly resolved DEMs even under the extreme illumination conditions typical of the lunar polar regions. The resulting DEMs can achieve pixel scales up to the native resolution of the Lunar Reconnaissance Orbiter Camera (LROC) Narrow Angle Camera (NAC) images, which is 0.7–1.5 m pix −1 at south polar latitudes. Here we present 5 m pix −1 SfS DEMs (SDEMs) for the list of 13 Artemis III candidate landing regions released in 2022. While our SDEMs match the resolution of the recently updated polar DEMs (or LDEMs) from the Lunar Orbiter Laser Altimeter, we use SfS to enhance them by introducing details from the LROC NAC images. The result is a complementary product which leverages the geodetic control of the LDEMs while also providing a more uniform effective resolution. To deal with the cumbersome preparation of properly selecting and coregistering NAC images, necessary to produce the SDEMs of such large regions, we developed a semi-automated SfS pipeline leveraging widely used open-source tools. We show that our accurate models are a powerful resource to quantify surface characteristics (e.g., slope, roughness, Sun and Earth illumination), to assess the viability of potential landing sites, and to plan surface activities.