Assessment of Mars Science and Mission Priorities (2003) / Chapter Skim
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6. Ground Ice, Groundwater, and Hydrology
6. Ground Ice, Groundwater, and Hydrology
Pages 48-53
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From page 48... ...
MGS Thermal Emission Spectrometer (TES) observations demonstrate the presence of small isolated regions rich in crystalline hematite, and analyses of SNC meteorites give evidence for the presence of low-temperature hydrated minerals in crustal rocks and of higher-temperature hydrated minerals deep within the mantle.8 Geomorphic evidence from Viking and MGS observations indicates that the layered deposits surrounding the north and south polar caps also contain water ice, but its mass fraction is currently not well constrained.9 One also expects to find near-surface ground ice on Mars, as on Earth;~° ii models predict that it should be present within the top meters of 48
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From page 49... ...
Liquid water on Mars is not expected to be stable on Mars today, because temperatures exceed 273 K only at low latitudes during the warmest periods of the day, and any liquid generated would quickly evaporate and be transported by the atmosphere to colder locations where it would then freeze. The most detailed observations of the behavior of martian water come from measurements of the column abundance of water vapor in the martian atmosphere from the Viking landers' Mars Atmosphenc Water Detector instruments,~7 i~ and more recently from MGS's TES.~9 These measurements show that atmospheric water vapor abundances reach maximum values of close to 100 precipitable microns at high northern latitudes during the summer season when the north polar water ice cap is exposed.
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From page 50... ...
At the present time, very little detailed information exists about the adsorptive capacity and diffusivity of the martian regolith,22 and without this information and an understanding of the behavior of water at the surface/atmosphere interface, it will be difficult to use models to extend our knowledge of the behavior of adsorbed water and near-surface ground ice. With respect to the question of deep liquid water environments, the absence of information regarding Mars's heat-flow rate and the permeability of the deep regolith results in even more severe limitations.
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From page 51... ...
The loss of Mars Observer in 1993 took with it the PMIRR and GRS instruments, which would have provided high-quality information about the present global distribution of water vapor in the atmosphere, and water ice and/or adsorbed water in the near-surface martian regolith. PMIRR was reflown on Mars Climate
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From page 52... ...
Future plans call for radar sounding to detect segregated ice and water deposits in the crust (e.g., the MARSIS radar experiment on Mars Express and the sounding radar planned for MRO)
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From page 53... ...
Christensen, "Recent TES Results: Mars Water Vapor Abundance and the Vertical Distribution of Aerosols," Bulletin of the American Astronomical Society 32: 3, 2000.
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