From a geologic perspective, the TES will be a very useful instrument. Measuring infrared emission from the surface in wavelengths from 6 to 50 microns, the TES can detect the thermal vibrations made in the crystalline structure of minerals.
Because each mineral type has a unique chemistry and structure, each vibrates at a unique frequency within the thermal infrared portion of the electromagnetic spectrum.
The TES will map the mineralogical composition of the entire martian surface at a resolution of about 3 kilometers (2 miles). TES data will also provide information about the grain size of surface sediments, monitor the size and quantity of suspended dust in the atmosphere, and observe the seasonal growth and retreat of the martian polar caps.
Below: Spectra of representative silicate and carbonate minerals in thermal emission using a commercial Mattson interferometer/spectrometer. Note the systematic variation in the 8 to 12 micrometer region in silicates due to changes in bond strength associated with changes in mineral structure.
Source: Christensen, P.R. et al., Thermal Emission Spectrometer experiment: Mars Observer mission, Journal of Geophysical Research, vol. 97, no. E5, pp. 7719-7734, 1992.