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Evidence for Water Ice on the Moon: Results for Anomalous Polar Craters from the LRO Mini-RF Imaging RadarThe Mini-RF radar instrument on the Lunar Reconnaissance Orbiter spacecraft mapped both lunar poles in two different RF wavelengths (complete mapping at 12.6 cm S-band and partial mapping at 4.2 cm X-band) in two look directions, removing much of the ambiguity of previous Earth- and spacecraft-based radar mapping of the Moon's polar regions. The poles are typical highland terrain, showing expected values of radar cross section (albedo) and circular polarization ratio (CPR). Most fresh craters display high values of CPR in and outside the crater rim; the pattern of these CPR distributions is consistent with high levels of wavelength-scale surface roughness associated with the presence of block fields, impact melt flows, and fallback breccia. A different class of polar crater exhibits high CPR only in their interiors, interiors that are both permanently dark and very cold (less than 100 K). Application of scattering models developed previously suggests that these anomalously high-CPR deposits exhibit behavior consistent with the presence of water ice. If this interpretation is correct, then both poles may contain several hundred million tons of water in the form of relatively "clean" ice, all within the upper couple of meters of the lunar surface. The existence of significant water ice deposits enables both long-term human habitation of the Moon and the creation of a permanent cislunar space transportation system based upon the harvest and use of lunar propellant.
Document ID
20150000268
Acquisition Source
Goddard Space Flight Center
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Spudis, P. D.
(Lunar and Planetary Inst. Houston, TX, United States)
Bussey, D. B. J.
(Johns Hopkins Univ. Laurel, MD, United States)
Baloga, S. M.
(Proxemy Research, Inc. Laytonsville, MD, United States)
Cahill, J. T. S.
(Johns Hopkins Univ. Laurel, MD, United States)
Glaze, L. S.
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Patterson, G. W.
(Johns Hopkins Univ. Laurel, MD, United States)
Raney, R. K.
(Johns Hopkins Univ. Laurel, MD, United States)
Thompson, T. W.
(Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Thomson, B. J.
(Boston Univ. Boston, MA, United States)
Ustinov, E. A.
(Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Date Acquired
January 8, 2015
Publication Date
October 3, 2013
Publication Information
Publication: Journal of Geophysical Research: Planets
Publisher: American Geoplysical Union
Volume: 118
Issue: 10
Subject Category
Lunar And Planetary Science And Exploration
Report/Patent Number
GSFC-E-DAA-TN12106
Distribution Limits
Public
Copyright
Public Use Permitted.
Keywords
Mini-RF radar
water ice
MoonaEuro(TM)s polar regions
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