LRO-LAMP Lunar South Pole Cold Traps: Assessment of H2O and Potential CO2 and NH3 Reserves

Nighttime Lyman Alpha Mapping Project (LAMP) observations are used to investigate condensed volatiles at the south polar region of the Moon. This study incorporates LAMP data from the first ∼7 years of the mission and Diviner annual maximum temperatures to search for volatile signatures associated with H₂O, NH₃, and CO₂. Other stable potential species, for example, SO₂ and H₂S, are not identifiable with the ultraviolet ratio-temperature techniques and are not directly addressed in this study. We confidently detect a ∼20% increase in normalized Off-band (175-190 nm) to On-band (148-162 nm) albedo ratios (consistent with condensed surface volatiles) at temperatures below ∼115 K. Elevated normalized ratios extend to temperatures capable of supporting pure aforementioned ices over geologically long time scales. Although ∼115 K is consistent with H₂O lifetimes of ∼1-Myr, the presence of CO₂ and NH₃ are not uniquely delineated by the data trends with temperature. Future spectral modeling to appropriately identify the composition and abundance of these condensed volatiles remains necessary. Normalized albedo ratios are further analyzed for candidate species via maximum temperatures to inform the likelihood of ice signatures: H₂O (70 K < T ≤ 115 K), NH₃ + H₂O (60 K < T ≤ 70 K), and CO₂ + NH₃ + H₂O (T ≤ 60 K). We compare normalized albedo ratios across seven regions of interest (ROI), including Faustini, Shoemaker, Haworth, Cabeus, Amundsen, Nobile, and an unnamed region. Such comparisons allow for characterization of relative abundances of volatiles across the ROI important for their utilization in future crewed and robotic missions to the Moon.