LRO-LAMP Observations of Cold-Trapped Volatiles at the Southern Polar Regions of the Moon

Characterization of condensed volatiles on the lunar surface is crucial for future crewed and robotic missions. Far-ultraviolet reflectance measurements of these volatiles are uniquely enabled by the Lyman Alpha Mapping Project (LAMP) spectrograph onboard the Lunar Reconnaissance Orbiter. LAMP utilizes illumination from ultraviolet-bright stars and interplanetary hydrogen emissions to study regions with maximum temperatures below 110 K (the stability temperature of pure water ice). These lunar cold traps enable volatiles to accumulate over billions of years (~1 mm/Ga). We build upon previous analyses by Gladstone et al., 2012 and Hayne et al., 2015 by accumulating observations acquired during nominal operations from 2009-2016. We examine the cold-trapped volatiles at five southern polar regions of interest: Haworth, Shoemaker, Faustini, Cabeus, and an unnamed region. Using Diviner temperature measurements in conjunction with LAMP we analyze albedo-temperature trends within each region of interest and isolate volatile populations. We will test the hypothesis that each volatile population is composed primarily of water ice mixed with varying amounts of lunar regolith. Using spectral mixing methods we model intimate mixtures of condensed water and lunar regolith at far-ultraviolet wavelengths. We will present comparisons between modeled and LAMP spectra, and preliminary water abundances within southern polar regions of interest.