The Thermal and Evolved Gas Analyzer (TEGA) includes a set of 8 sample ovens, 8 reference ovens, and a tunable diode laser (TDL) spectrometer. The Robotic Arm (RA) acquires and images each sample, then deposits the sample into an oven where it is heated to 950 °C. The spectrometer determines the amounts of carbon dioxide and water vapor evolved from the samples over time. From this, the TEGA will determine the concentrations of ices, adsorbed volatiles and volatile-bearing minerals in surface and subsurface materials. The ovens are not reusable; TEGA is designed to analyze 8 soil samples. During each run, an emtpy reference oven is heated to the same temperature as a sample-filled oven. The difference in energy required to heat the ovens can be used to infer the presence of water ice and minerals containing water or carbon dioxide.

TEGA was built under the direction of William Boynton at the University of Arizona. Laurie Leshin (Arizona State University) is the Co-Investigator.