Characterization of Mass Wasting Events on Lunar Maria Using Mini‐RF Radar Observations

Abstract Evidence of mass wasting has been observed on the Moon since at least the Apollo era. Surface features indicative of mass wasting processes are traditionally characterized geomorphologically using visible images. In this study, we aim to better understand mass wasting features via their radar properties, which can provide insights into the surface/shallow subsurface wavelength‐scale roughness and rock properties. We mapped mass‐wasting events in the mare region on the Moon in high‐resolution Lunar Reconnaissance Orbiter Camera images (∼50 cm/px) taken by NASA's Lunar Reconnaissance Orbiter (LRO) mission. We analyzed the features in LRO Mini‐RF monostatic, S‐band radar data (∼90 m/px) and presented their polarimetric radar properties, in particular their circular polarization ratio, same sense and opposite sense polarization backscatter intensity, and m‐χ decomposition components. We also compared the radar products to other remote sensing data sets such as slope (∼59 m/px; from LRO Lunar Orbiter Laser Altimeter data) and rock abundance (∼237 m/px; from LRO Diviner data). We find that the presence of mass wasting features depolarizes the backscattered radar echoes more than the signals returned from surrounding surfaces, making these features identifiable in m‐χ decomposition products. We demonstrate that radar polarimetric imaging is a good tool for mapping mass wasting and helpful for future studies where illumination conditions are not ideal for visual identification of surface features (e.g., regions in permanent shadow). Such radar products could also be used to identify mass wasting for risk mitigation and mission planning for future robotic or human landings on the Moon.