ShadowCam Establishes Faustini’s Ancient Age

Abstract

ShadowCam is a NASA-funded imaging experiment onboard the Korea Pathfinder Lunar Orbiter (also known as Danuri), providing high-resolution (2 m/pixel) images of permanently shadowed regions (PSRs), enabling investigations into the distribution and accessibility of water ice and other volatiles necessary for future human exploration. Here, we use a ShadowCam image mosaic to revisit the crater-size frequency distribution (CSFD) of Faustini crater floor, the third-largest PSR, and of high cold-trapping potential. We find that all count areas exhibit crater equilibrium over the entire diameter range (< 2 km), hence supporting an ancient age for the Faustini impact and surface floor materials. In addition, we estimate the amount of basin ejecta material delivered to Faustini crater from the Imbrium, Orientale, and Schrödinger formation events using an ejecta distribution model to investigate the origin of a previously identified disturbance in the CSFD. As expected, the model originally developed for simple and complex craters yielded inconsistent results, underscoring the need for further studies and a deeper understanding of ejecta thickness distribution for the basin-sized impact regime.