The Thermal and Evolved Gas Analyzer (TEGA) is a combination of a high-temperature furnace with a mass spectrometer.
It was used to bake samples of Martian dust and determine the composition of the resulting vapors.
It has eight ovens, each about the size of a large ball-point pen, which were able to analyze one sample each, for a total of eight separate samples.
Team members measured how much water vapor and carbon dioxide gas were given off, how much water ice the samples contained, and what minerals are present that may have formed during a wetter, warmer past climate.
The instrument also measured organic volatiles, such as methane, down to 10 ppb.
TEGA was built by the University of Arizona and University of Texas at Dallas.

On May 29, 2008 (sol 4), electrical tests indicated an intermittent short circuit in TEGA, resulting from a glitch in one of the two filaments responsible for ionizing volatiles.
NASA worked around the problem by configuring the backup filament as the primary and vice versa.

In early June, first attempts to get soil into TEGA were unsuccessful as it seemed too "cloddy" for the screens.

On June 11 the first of the eight ovens was filled with a soil sample after several tries to get the soil sample through the screen of TEGA.
On June 17, it was announced that no water was found in this sample; however, since it had been exposed to the atmosphere for several days prior to entering the oven, any initial water ice it might have contained could have been lost via sublimation.
The Thermal and Evolved Gas Analyzer (TEGA) is a combination of a high-temperature furnace with a mass spectrometer. It was used to bake samples of Martian dust and determine the composition of the resulting vapors. It has eight ovens, each about the size of a large ball-point pen, which were able to analyze one sample each, for a total of eight separate samples. Team members measured how much water vapor and carbon dioxide gas were given off, how much water ice the samples contained, and what minerals are present that may have formed during a wetter, warmer past climate. The instrument also measured organic volatiles, such as methane, down to 10 ppb. TEGA was built by the University of Arizona and University of Texas at Dallas.
On May 29, 2008 (sol 4), electrical tests indicated an intermittent short circuit in TEGA, resulting from a glitch in one of the two filaments responsible for ionizing volatiles. NASA worked around the problem by configuring the backup filament as the primary and vice versa.
In early June, first attempts to get soil into TEGA were unsuccessful as it seemed too "cloddy" for the screens.
On June 11 the first of the eight ovens was filled with a soil sample after several tries to get the soil sample through the screen of TEGA. On June 17, it was announced that no water was found in this sample; however, since it had been exposed to the atmosphere for several days prior to entering the oven, any initial water ice it might have contained could have been lost via sublimation.
Phoenix (spacecraft)