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Planetary Fourier Spectrometer (PFS)

NSSDCA ID: 2003-022A-03

Mission Name: Mars Express
Principal Investigator:Dr. Vittorio Formisano


The Planetary Fourier Spectrometer (PFS), is a Fourier infrared spectrometer designed for atmospheric studies. The scientific objectives are to obtain spectra of gases (especially trace gases) in the martian atmosphere in order to determine the three-dimensional temperature-field up to 50 km altitude, map constituent variations (water and carbon dioxide), search for other trace components, make a new determnination of the D/H ratio, profile the optical properties of atmospheric aerosols, and study global atmospheric circulation. PFS will also be used for surface studies, including monitoring of surface temperature to determine thermal inertia and constrain mineralogical properties, determine the nature of the surface condensate and seasonal variations of its composition, study surface-atmosphere exchange processes and make measurements of scattering phase function and pressure and local height determination for selected areas.

The PFS instrument is a double pendulum interferometer divided into a short-wavelength (SW) and long-wavelength (LW) channel. The SW channel covers spectra from 2000 to 8333 cm^-1 (1.2 to 5.0 micron wavelength) at 2 cm^-1 resolution. This channel uses a PbSe photoconductor detector and a CaF2 beamsplitter. The field of view is about 2 degrees, giving a footprint of about 10 km at periapsis. The LW channel covers 222 - 2000 cm^-1 (5.0 to 45.0 micron) at 2 cm^-1 resolution, using a LiTaO3 pyroelectric detector and CsI beamsplitter. The field of view is about 4 degrees, corresponding to a periapsis footprint of roughly 20 km. Both channels have a measurement cycle time of 10 seconds.

The experiment will operate primarily for two hours each orbit centered on periapsis. The nominal periapsis altitude is 300 km. PFS will operate prmarily in a nadir-looking position, but has a pointing device to allow it to operate in a phase-angle mode (looking at the same spot on the surface from different angles on different orbits) and a limb-looking mode, nearly tangent to the surface of the planet. Peak operating power will be 45 W , while the sleeping power is of the order of 14 W. Onboard real time FFT will be used to select the spectral range of interest for data transmission to ground and for data compression. The PFS instument is derived from the Russian Mars-96 mission.

Alternate Names

  • MarsExpress/PFS
  • PFS
  • urn:esa:psa:context:instrument:mex.pfs

Facts in Brief

Mass: 33.4 kg
Power (avg): 23 W
Bit rate (avg): 8.3 kbps


  • Planetary Science: Atmospheres
  • Planetary Science: Geology and Geophysics

Additional Information

Questions and comments about this experiment can be directed to: Dr. David R. Williams



NameRoleOriginal AffiliationE-mail
Dr. Vittorio FormisanoPrincipal

Selected References

  • Formisano, V., et al., PFS for Mars Express: A new approach to study Martian atmosphere, Adv. Space Res., 29, No. 2, 131-142, 2002.
  • Formisano, V., et al., Detection of methane in the atmosphere of Mars, Science, 306, No. 5702, 1758-1761, Dec. 2004.
  • Grassi, D., et al., PFS: an effective instrument for the study of martian environment, Adv. Space Res., 34, No. 8, 1696-1701, 2004.
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