This instrument studied the atmosphere and mapped the mineral composition of the surface by analysing infra-red radiation, which scanned for heat emitted from the surface of Mars. The TES instrument systematically measured and monitored the Martian surface and atmosphere throughout all phases of the mission. The TES spectrometer collected over 206 million infrared spectra, and the TES bolometer was in continual full-time use throughout the entire mission.
TES was and is both an instrument and a technique. The Thermal Emission Spectrometer was a scientific instrument that first flew aboard the Mars Observer spacecraft. Following the loss of that spacecraft, TES was rebuilt and launched along with five of the original seven Mars Observer instruments aboard the Mars Global Surveyor spacecraft. The purpose of TES was to measure the thermal infrared energy (heat) emitted from Mars. This technique, called thermal emission spectroscopy, can tell us much about the geology and atmosphere of Mars. TES data provided the first detailed look at the composition of Mars.
The Thermal Emission Spectrometer discovered new mineralogical and topographic evidence that suggested Mars had abundant water and thermal activity in its early history.
Data indicated clear evidence of an ancient hydrothermal system, implying that water was stable at or near the surface and that a thicker atmosphere existed in Mars' early history.
Measurements showed an accumulation of the mineral hematite, a mineral that typically originates in standing bodies of water, near the Martian equator. This deposit of hematite, and knowledge of other minerals on the surface of Mars, helped scientists direct the Mars Exploration Rovers to the Meridiani Planum and Gusev Crater.
Principal investigator is Dr. Phil Christensen, Arizona State University.