What advantages does the Thermal and Evolved Gas Analyzer (TEGA) have over the Viking missions Gas Chromatograph in detecting organics?
The Phoenix mission has two advantages over the Viking mission with respect to organics. The first is that Phoenix is slowly heating the sample to 1000 C, whereas Viking heated very quickly to 500 C. There are many organics thought to be possibly stable on Mars that vaporize in the 700 C to 800 C range. These types of organics are often call kerogens. The other is the location where Phoenix is landing. The Viking mission showed that water can neutralize the effect of the strong oxidant that is hypothesized to be responsible for destroying organics. It is thought that the ice in the polar regions might also protect the sample. In terms of the ultimate sensitivity, the instruments are comparable. It is the nature of the sample the generates the gas that goes to the mass spectrometer that provides the advantage to Phoenix.
