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The Young Age of the LAMP-Observed Frost in Lunar Polar Cold TrapsThe Lunar Reconnaissance Orbiter/Lyman Alpha Mapping Project (LAMP) ultraviolet instrument detected a 0.5–2% icy regolith mix on the floor of some of the southern pole permanently shadowed craters of the Moon. We present calculations indicating that most or all of this icy regolith detected by LAMP (sensed to a depth of <1 μm) has to be relatively young—less than 2,000 years old—due to the surface erosional loss by plasma sputtering (external ionized gas‐surface interactions), meteoric impact vaporization, and meteoric impact ejection. These processes, especially meteoric impact ejection, will disperse water along the crater floor, even onto warm regions where it will then undergo desorption. We have determined that there should be a water exosphere over polar craters (e.g., like Haworth crater) and calculated that a model 40‐km‐diameter crater should emit ~10(exp 19) H2O per second into the exosphere in the form of free molecules and ice‐embedded particulates.



Document ID
20190033298
Acquisition Source
Goddard Space Flight Center
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Farrell, W. M.
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Hurley, D. M.
(Southwest Research Inst. San Antonio, TX, United States)
Poston, M. J.
(Colorado Univ. Boulder, CO, United States)
Szalay, J. R.
(Princeton Univ. Princeton, NJ, United States)
McLain, J. L.
(Maryland Univ. College Park, MD, United States)
Date Acquired
November 29, 2019
Publication Date
July 1, 2019
Publication Information
Publication: Geophysical Research Letters
Publisher: American Geophysical Union
Volume: 46
Issue: 15
ISSN: 0094-8276
e-ISSN: 1944-8007
Subject Category
Lunar And Planetary Science And Exploration
Report/Patent Number
GSFC-E-DAA-TN75728
Funding Number(s)
CONTRACT_GRANT: 80NSSC17K0702
Distribution Limits
Public
Copyright
Use by or on behalf of the US Gov. Permitted.
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