What Is TES?
Mars Global Surveyor (MGS) launched from Cape Canaveral Air Station on 7 November 1996 and was successfully put into orbit around Mars on 12 September 1997. On 31 January 2001, MGS completed the mapping phase of the mission, which lasted one martian year (two Earth years). On 2 November 2006, mission controllers lost contact with the spacecraft, ending the mission.

The TES instrument systematically measured and monitored the Martian surface and atmosphere throughout all phases of the mission. The TES spectrometer collected over 206 million infrared spectra, and the TES bolometer was in continual full-time use throughout the entire mission.

TES was and is both an instrument and a technique. The Thermal Emission Spectrometer was a scientific instrument that first flew aboard the Mars Observer spacecraft. Following the loss of that spacecraft, TES was rebuilt and launched along with five of the original seven Mars Observer instruments aboard the Mars Global Surveyor spacecraft. The purpose of TES was to measure the thermal infrared energy (heat) emitted from Mars. This technique, called thermal emission spectroscopy, can tell us much about the geology and atmosphere of Mars. TES data provided the first detailed look at the composition of Mars. Follow the links to find out how this works.

Thermal Emission Spectroscopy: the Technique
Thermal Emission Spectrometer: the Instrument

How many TES spectra were collected?

The following table shows the final count of TES spectra collected during the aerobraking, mapping, and extended phases of the mission. The number of spectra collected in any given month varied according to the rate at which data could be returned, the number of spacecraft maneuvers that precluded "typical" data acquisition patterns, and other factors. These counts do not include other data types (e.g., albedo, bolometer) collected by TES. For explanations of the terms below, see the TES/THEMIS glossary.

Data Collected
Aerobraking
Mapping
Extended
Total
Full Spectral/Spatial Resolution
6,873,276
62,747,994
46,409,928
116,031,198
Full Spectral Resolution/Spatially Masked
0
2,041,257
30,580,199
32,621,456
Spectrally Masked/Full Spatial Resolution
4,820,826
19,320,372
135,036
24,276,234
Spectrally Masked/Spatially Masked
0
7,469,346
25,821,241
33,290,587
Total Number of TES Spectra Collected
11,694,102
91,578,969
102,946,404
206,219,475

Aerobraking phase: Mars Surveyor Project (MSP) orbits 3 - 1583
Mapping phase: MSP orbits 1584 - 1683 and 0 - 8504*
Extended mission: MSP orbits 8505 - 27235

*The MSP reset the orbit count to zero after orbit/rev 1683 (the official start of mapping operations); TES was already making "mapping" style observations as of orbit 1583 and the team did not reset its orbit counter. To match MSP orbit numbers with TES orbit ("ock") numbers in the PDS-distributed data, add 1683 to the MSP orbit number.