Lunar Observer Iaser Altimeter Observations for Lunar Base .- Site Selection

One of the oqtical datasets for optimal selection of future lunar lana_ng sites is local, to regional-scale topography. Lunar base site selection will require such data for hoth engineering and scientific olX,rations purposes. The Lunar Geosctence Orbiter or Lunar Obsert_or is the ideal precursory science mission from which to obtain this required information. We suggest that a simple laser altimeter instrument could be employed to measure local-scale slopes, heights, and depths of lunar surface features important to lunar base/ganntng and design. For this reason, we hate designed and are currently constructing a of a Lunar Observer Laser Altimeter (LOLA) instrument capable of acquiring contiguousfoo_int topographic profiles with both 30_m and 30tgrn along-track resolution. Ibis instrument meets all the severe weight, pour size, and data rate limitations imposed by Obse_r_lass spacecraft. In axldttion, LOLA would be capable of measuring the withinfootlrdnt t_rticaI roughness of the lunar surface, and the 1.06-#m relative surface reflectivity at normal incidence. We bate used _ laser altimeter data for a few representatite lunar analog landforms to simulate and analyze LOLA performance in a lOOd_m lunar orbit. We demonstrate that this system in its highest resolu_m mode (30-m diameter foogra'nts) umuld quantify the topography of all but the veD, smallest lunar tandforms. At its global mapping resolution (300.m diameter foo_trdnts), LOLA would establish the topographic context for lunar landing site selection by providing the basis for constructing a 1-2 km spatial resolution global, geodetic topograptMc grid tbat would contain a bigh den_'ty of observations (e.g., -1000 observations per each 10 by 1° cell at the lunar equator). The high spatial and vertical resolution measurements made ugth a LOLA-cIa,cs instrument on a precursory Lunar Observer would be highly s3rneeggstic with high, resolution imaging datasets, and will allow for direct quantification of critical slopes, heights, and depths of features visible in images of potentiaI lunar base sites.