Mini-TES at Meridiani Planum: An Overview of Infrared Spectroscopy at the Opportunity Landing Site

The landing site for the Mars Exploration Rover, Opportunity, was chosen based on orbital spectral evidence of hematite distributed in a localized region on the Meridiani plains. Prior to landing, the formation mechanism was subject to debate, though many favored an aqueous origin. Once on the surface, the Miniature Thermal Emission Spectrometer (Mini-TES) rapidly confirmed the orbital identification and demonstrated that the spectral signature was associated with small spherules, now interpreted as hematitic concretions formed in porous, sulfate-rich sediments. Observations during the four and a half years of mission operations have included stares and scans on the plains, spot observations of a wide variety of outcrop blocks exposed in numerous craters, vertical scans and stares of exposed stratigraphy in the large cliff faces of Endurance Crater, and systematic observations of surfaces near the rover during long traverses. While the infrared spectral character of the spherules is unchanged along the 11 kilometer traverse to Victoria Crater, Mini-TES has cataloged subtle differences in outcrop signatures and variations in spectral features associated with bound water. Continuous slow accumulation of dust on the pointing mirror and other optical components led to the ultimate obscuration of the instrument and suspension of data acquisition on Sol 1328, October 20, 2007. This presentation will provide an overview of the thermal emission spectral properties of the Meridiani soil and rock units.