Thermal and Evolved Gas Analyzer

This article is about the soil analysis instrument used on the Phoenix Mars mission.

Also known under the acronym of TEGA The design has been based on experience gained from the Mars Polar Lander. Soil samples taken from the Martian surface by the robot arm are eventually delivered to the TEGA, where they are heated in an oven to about 1,000ºC. This heat causes the volatile compounds to be given off as gasses which are sent to the mass spectrometer for analysis. This spectrometer is adjusted to measure particularly the isotope ratios for hydrogen, oxygen, carbon, nitrogen, and heavier gases. Detection values as low as 10 parts per billion. The Phoenix TEGA has 8 ovens, which are enough for 8 samples.