Open AccessThermal and Evolved Gas Analyzer: Part of the Mars Volatile and Climate Surveyor integrated payload
Author(s) -
Boynton William V.,
Bailey Samuel H.,
Hamara David K.,
Williams Michael S.,
Bode Rolfe C.,
Fitzgibbon Michael R.,
Ko WenJeng,
Ward Michael G.,
Sridhar K. R.,
Blanchard Jeff A.,
Lorenz Ralph D.,
May Randy D.,
Paige David A.,
Pathare Asmin V.,
Kring David A.,
Leshin Laurie A.,
Ming Douglas W.,
Zent Aaron P.,
Golden D. C.,
Kerry Kristopher E.,
Lauer H. Vern,
Quinn Richard C.
Publication year - 2001
Publication title -
journal of geophysical research: planets
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/1999je001153
Subject(s) - differential scanning calorimetry , analytical chemistry (journal) , calorimeter (particle physics) , exothermic reaction , mars exploration program , endothermic process , carbon dioxide , chemistry , mineralogy , materials science , environmental science , environmental chemistry , astrobiology , physics , thermodynamics , organic chemistry , optics , adsorption , detector
The Thermal and Evolved Gas Analyzer (TEGA) on the Mars Polar Lander spacecraft is composed of two separate components which are closely coupled: a Differential Scanning Calorimeter (DSC) and an Evolved Gas Analyzer (EGA). TEGA has the capability of performing differential scanning calorimetry on eight small (0.038 mL) soil samples selected in the vicinity of the lander. The samples will be heated in ovens to temperatures up to 950°C, and the volatile compounds water and carbon dioxide, which are released during the heating, will be analyzed in the EGA. The power required by the sample oven is continuously monitored during the heating and compared to that required to heat simultaneously a similar, but empty, oven. The power difference is the output of the DSC. Both endothermic and exothermic phase transitions can be detected, and the data can be used in the identification of the phases present. By correlating the gas release with the calorimetry, the abundance of the volatile compounds associated with the different phases can be determined. The EGA may also be able to detect the release of oxygen associated with any superoxide that may be on the surface of the soil grains. The instrument can detect the melting of ice in the DSC down to abundances on the order of 0.2% of the sample, and it can detect the decomposition of calcite, CaCO 3 , down to abundances of 0.5%. Using the EGA, TEGA can detect small amounts of water, down to 8 ppm in the sample, and it can detect the associated release of CO 2 down to the equivalent abundances of 0.03%. The EGA also has the ability to determine the 13 C/ 12 C ratio in the evolved CO 2 , but it is not clear if the accuracy of this ratio will be sufficient to address the scientific issues.