Odyssey THEMIS Views of the Candidate MER Landing Sites

The Mars Odyssey Thermal Emission Imaging System (THEMIS) has obtained infrared and visible images of seven candidate MER landing sites. Both day and night mosaics of the landing ellipse and the surrounding terrain have been produced, providing a new look at the geology, morphology, composition, and thermophysical properties of these regions. The Meridiani "hematite" site identified by the MGS TES instrument as having a unique mineral signature of grey crystalline hematite remains a strong scientific and engineering candidate based on the multi-spectral and thermophysical properties derived from THEMIS IR images. This area is part of a sequence of geologic units that are defined by their physical and compositional properties. This region has little dust mantle, increasing the likelihood of sampling exposed rocks at the surface. Gusev crater has been examined and found to have variations in both compositional units and thermophysical properties. This region has significant dust cover, making detailed prediction of composition from remote sensing difficult. The Isidis basin has been imaged extensively at resolutions of 100-m (IR) and 18-m (visible) that are better than obtained by Viking and with significantly greater areal coverage than obtained by the MGS MOC camera. The ancient cratered highlands south of the Isidis landing ellipse have extensive fluvial dissection. However, the THEMIS images provide evidence that the basin surface north of the highlands where the ellipse is located has embayed the major channels leading from the highlands, likely burying the deposits from these channels. Finally, several potential sites in the Elysium region have been investigated and found to have essentially the same characteristics as determined from previous imaging and spectroscopic observations. Athabasca, Eos Chasma, and Melas Chasma were initially candidate landing sites and have been extensively imaged by THEMIS. These sites, while no longer candidates for the MER Rovers, will be briefly discussed.