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Exospheric transport restrictions on water ice in lunar polar traps
Author(s) -
Hodges R. Richard
Publication year - 1991
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/91gl02533
Subject(s) - regolith , astrobiology , water ice , polar , vaporization , solar wind , comet , liquid water , environmental science , geology , atmospheric sciences , geophysics , earth science , physics , astronomy , plasma , quantum mechanics , thermodynamics
There is little doubt that at least 10 17 g of water has accreted on the moon as a result of the reduction of ferric iron at the regolith surface by solar wind protons, the vaporization of chondrites, and perhaps comet impacts. Lacking an efficient escape mechanism, most of this water (or its progeny) is probably on the moon now. If the water were to have migrated to permanently shaded cold traps near the lunar poles, ice deposits with densities greater than 1000 g cm −2 would cover the traps, providing accessible resources. However, exospheric transport considerations suggest that the actual amount of water ice in the cold traps is probably too small to be of practical interest. The alternative is global assimilation of most of the water into the regolith, a process that must account for about 30 micromoles of water per gram of soil.