MAPPING WATER ICE ON THE LUNAR SURFACE: COMBINED RESULTS FROM EXISTING REMOTE SENSING DATASETS

Two decades of remote sensing data from several satellites show that lunar water ice and other volatiles exist within the 30,000 km2 [1] of the Moon’s surface that is permanently shadowed. However, the precise spatial distribution of water ice on the Moon is not yet well understood. Initial radar observations from Arecibo and the Clementine Bistatic Radar Experiment did not reproducibly detect macroscopic water ice deposits at or near the Lunar surface [3-4]. Later, infrared spectra directly detected surface water ice in select craters using spectroscopy in UV, near-infrared albedo, and temperature also consistent with ice [2]. Additionally, the depth-diameter ratios of simple craters on the Moon, shallow significantly with latitude, suggesting that macroscopic deposits of volatiles in-fill craters on the Lunar surface [5].

To create a comprehensive map of water ice indicators on the Lunar surface, datasets collected by the following instruments were utilized: M3 (infrared spectra), LAMP (far-ultraviolet spectra), LEND and NS (neutron spectra), LOLA (topography and albedo), both Mini-RFs (albedo and polarization), LROC (surface visible albedo), and Diviner (surface temperature). Although the raw data for each of these instruments are publicly accessible from NASA’s Planetary Data System Geoscience Node, we utilize previously published derived products when possible to efficiently build upon the data processing already conducted.

Measurements and observed surface conditions consistent with the presence of water ice were spatially coregistered in ArcGIS and their correlations tested for statistical significance using Python. Since these instruments possess different spatial resolutions and different depths below the surface at which they can detect water ice, we aim to differentiate areas with water ice at the surface versus buried below the Lunar surface.

For future robotic missions to study the Moon’s current and past geology and potential in situ resource utilization (ISRU), ascertaining with certainty the composition, location, and abundance of the water ice deposits on the Lunar surface is crucial.

[1] Mazarico et al. Icarus. 2010

[2] Li et al. PNAS. 2018

[3] Stacy et al. Science. 1997

[4] Simpson and Tyler JGR. 1999

[5] Rubanenko et al. Nature Geosci. 2019