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Project Progress

Subsurface Habitability on Mars: Armstrong and Sondossi (2005) are exploring the stability of deep subsurface environments (3-6 km) on Mars. Thermal diffusion models indicate that temperature fluctuations at these depths are minor, and provide reasonable environments for sub-surface life, perhaps probed by the recent detection of methane in Mars’ atmosphere. Figure 1 shows temperature profiles as well as possible methane diffusion profiles in the regolith.

The Habitability of Early Mars: Armstrong and colleagues at the NASA Ames Mars GCM group are exploring the effects of an early, cold, low atmospheric pressure Mars under early, low-luminosity conditions. So far, we have run models spanning the parameter space from 0.1 to 100 mbars and axial tilts of 0 to 60 degrees to examine how the early sun affects both atmospheric collapse and polar cap formation. We also examine the possibility of surface liquid water for present and early Mars (Van Shaar and Armstrong, 2005)

Probing sub-surface ice in polar craters: Armstrong and colleagues at the United States Geological Survey are exploring the distribution of sub-surface water ice in polar craters using TES, MOC, and THEMIS measurements. (Korolev, Armstrong et al. 2005, Figure 2)

Enceladus: The Solar System’s Newest potentially habitable environment: The recent Cassini UVIS discovery of water vapor plumes ejected from the south pole of the Saturnian satellite, Enceladus, presents a unique window of opportunity for the detection of extant life in our solar system. With its significant geothermal energy source propelling these plumes 80 km from the surface of the moon and the ensuing large temperature gradient with the surrounding environment, it is possible to have the weathering of rocks by liquid water at the rock/liquid water interface, an environment that might support life. We submitted a paper this year exploring the possibility of habitable environments on Europa, and describing the search for signatures of these species and organics in the Cassini UVIS spectra. In addition, we obtained Director’s Discretionary Time to attempt to observe the Enceladus plume with the Spitzer Space Telescope. Spitzer data of Enceladus were successfully taken and are currently under analysis to search for evidence of plume activity.

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