P060-03
Compact Lunar Hydration and Mineralogy Explorer (CLuHME)

Monday, 14 December 2020: 16:08
Virtual
Tilak Hewagama1, Shahid Aslam2, Dina M Bower3, Murzy D Jhabvala4, Timothy A Livengood5, Donald E Jennings2, Geronimo Villanueva2 and Noah E Petro6, (1)NASA Goddard Space Flight Center, Code 553, Greenbelt, MD, United States, (2)NASA Goddard Space Flight Center, Greenbelt, MD, United States, (3)University of Maryland College Park, College Park, MD, United States, (4)NASA Goddard Space Flight Center, Greenbelt, United States, (5)University of Maryland College Park, Astronomy, College Park, MD, United States, (6)NASA GSFC, Greenbelt, MD, United States
Recorded Presentation
Abstract:
Compact Lunar Hydration and Mineralogy Explorer (CLuHME) is a MWIR/LWIR (2.5-12.5 µm) hyperspectral imaging instrument to identify and characterize lunar materials and ice(s) on surface and walls with sub-cm spatial resolution spectroscopic data cubes from 1 meter to horizon from a lunar lander, rover, or as a handheld by an astronaut in the field.

Mapping the distribution of water, hydroxyl (radial or groups), minerals, thermal properties, and regolith fine structure are relevant to understanding the lunar water cycle and for in situ resource utilization. The primary lunar mineralogic composition includes pyroxene, olivine, anorthite, ilmenite, and spinel, all of which contain a significant fraction of oxides by mass. Lunar highland material (theorized as original crust) is dominated by plagioclase feldspar and poor in pyroxene and olivine. In comparison, basaltic lava flow mare are a mix of plagioclase, orthopyroxene, clinopyroxene, olivine, and ilmenite. CLuHME on a polar lander can reveal the “geology of the South-Pole Aitken basin.”

A recent study estimated ~100 billion metric tons of near surface water ice may be distributed in lunar cold traps. CLuHME optical sensing technology is based on the 3 µm (~3200-3700 cm-1, stretching-modes) vibrational bands associated with both water (nu1/nu3) and OH (nu1). An analysis of lunar equatorial soils concluded solar-wind produced OH was a viable source for water ice in polar cold-traps with slower degassing rates. Discrimination of water-bearing from OH-bearing minerals is critical to plan resource recovery operations. As indicated by a reflectance trough, the 6 µm (1595 cm-1, nu2 bending-mode vibrational band) of monomer ice (e.g., Ih state) results in an emissivity peak unique to water (from OH), seen in dirty ice, but absent from OH-hydrates. One more signature of interest is the 12 µm (780 cm-1 libration) band of water. For thermal observations, control of the viewing (emission) angle is relevant given the angular dependence of emissivity.

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