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

Abstract

Abstract 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 H 2 O, NH 3 , and CO 2 . Other stable potential species, for example, SO 2 and H 2 S, 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 H 2 O lifetimes of ∼1‐Myr, the presence of CO 2 and NH 3 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: H 2 O (70 K < T ≤ 115 K), NH 3 + H 2 O (60 K < T ≤ 70 K), and CO 2 + NH 3 + H 2 O ( 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.