Remote Sensing and Geologic Studies of the Southeastern Quadrant of the Moon

Introduction: The southeastern quadrant of the lunar nearside is of interest both geologically and for planning for future landed missions. This region contains both cratered highland terrain, representing stratigraphic contributions from large impact basins, and younger mare deposits. We report here on remote sensing studies of an area extending from Tycho crater in the northwest to Mare Australe in the east, and south to the pole. We use new 70-cm Earthbased delay-Doppler radar observations at 450m / pixel in concert with compositional information obtained from Clementine multispectral reflectance data. These observations are augmented by 12.6-cm radar data at 20-100m / pixel for selected areas. Issues to be addressed include: distribution of materials associated with basin impacts, including Orientale, Nectaris, and other large southern basins; physical and chemical properties of these deposits; and implications for landing site evaluation. Recent studies have used new 70-cm Earth-based radar measurements in concert with other datasets to investigate radar-dark haloes of block-poor impact ejecta surrounding nearside craters [1], distal meltrich material associated with the Orientale impact [2], and potential ice deposits in permanently shadowed craters near the south pole [3]. The results of these previous studies are relevant for our current work, which seeks to construct a coherent geologic view of the southeastern limb region, including the south pole.