The Mars Global Surveyor, Thermal Emission Spectrometer (TES) is an imaging Fourier spectrometer with the following capabilities:
|Wavelength Range||6.25 - 50 microns|
|Number of Channels||143, 286|
|Spectral Sampling||10 or 5 wavenumbers|
|Bandpass (FWHM)||10 or 5 wavenumbers|
|Pixel Size||9 milliradian|
|Spatial Image Size||3 x 2 pixels|
The TES has 6 detectors in a 3 (across) by 2 pixel array. The spectrum is obtained by scanning a Michelson Interferometer (Fourier spectrometer). The scan time is 2 seconds in 10 wavenumber mode and 4 seconds in 5 wavenumber mode. At the nominal mapping orbit, each TES detector sees a 3 kilometer spot on the ground. Spacecraft motion moves the spacecraft 2 fields of view during the 2 second integration, so the TES does image motion compensation and obtains 2 pixels downtrack then jumps ahead 2 pixels. Thus continuous swaths of 3 pixels wide are obtained. Multiple orbits of data are used to obtain global maps at 3 km spatial resolution.
MGS is now in orbit around Mars in an elliptical orbit. The orbit will be fine tuned for the mapping phase in 1999.
TES finds large-grained hematite on Mars, larger than is typical of the fine grained to nano-crystalline hematite that covers the planet. This large-grained hematite may be indicative of hydrothermal systems active in Mars' past. For more detailes, see the Mars Global Surveyor TES Home Page (June, 1998)
Christensen, P.R., D.L. Anderson, C.C. Stillman, R.N. Clark, H.H. Kieffer, M.C. Malin, J.C. Pearl, J.C. Carpenter, N.B. Bandera, F.G. Brown, and S. Silverman, Thermal Emission Spectrometer Experiment: Mars Observer Mission, J. Geophys. Res. 97 7719-7734, 1992.
Christensen, P.R., D.L. Anderson, S.C. Chase, R.T. Clancy, R.N. Clark, B.J. Conrath, H.H. Kieffer, R.O. Kuzman, M.C. Malin, J.C. Pearl, T.L. Roush, and M.D. Smith, Initial Results from the Mars Global Surveyor Thermal Emission Spectrometer Investigation, Science, 279, 1692-1698, 1998.
U.S. Geological Survey,
a bureau of the U.S. Department of the Interior
This page URL= http://speclab.cr.usgs.gov/spacecraft-planetary/mgs-tes/tes1.html
This page is maintained by: Dr. Roger N. Clark firstname.lastname@example.org
Last modified Oct 28, 1999.