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SIRTF (Spitzer, SST)


The SIRTF (Space Infrared Telescope Facility) is a 1 meter class, cryogenically cooled space telescope operated as an observatory for infrared astronomy in the 3 - 180 micron range. The observatory is the final element of NASA's four Great observatories. The main objectives of the mission are:

  • physical studies of the planetary system;
  • detailed study of cold circumstellar dust clouds;
  • a search for the enigmatic brown dwarfs;
  • extension of IRAS studies of forming stars to lower temperatures and luminosities;
  • identification and study of powerful infrared galaxies; and,
  • infrared measurements of all presently catalogued quasars.

The spacecraft consists of an octagonal bus structure, and a solar array to power the science instruments. The pointing contron subsystem employs a celestial-inertial, three-axis stabilized control system. SIRTF is planned to have an Earth-trailing Heliocentric orbit.

Unlike IRAS (Infrared Astronomical Satellite), which swept rapidly across the sky, SIRTF will be a true observatory, carrying a variety of focal plane instruments. The SIRTF telescope is a lightweight reflector of Ritchey-Chretien design. The instruments selected include:

  • a four-channel infrared array camera imaging at 3.6, 4.5, 5.8, and 8 microns.
  • an imaging photometer, with three detector arrays imaging at 24, 70, and 160 microns (one array will also take low-resolution spectra at 50 - 100 microns);
  • a spectrograph providing high- and low-resolution spectroscopy at mid-infrared wavelengths (5-40 microns).

The instrument sensitivity is expected to be increased by a factor of 100 to 1000 over that of IRAS, and the spatial resolution will be at least a factor of 10 times finer than IRAS.

SIRTF has been renamed Spitzer Space Telescope (SST) in December 2003.

Nation: USA
Type / Application: Astronomy, Infra-Red
Operator: NASA
Contractors: Lockheed Martin (Bus), Ball Aerospace (Telescope)
Equipment: see above
Power: Solar cells, batteries
Mass: 923 kg
Orbit: heliocentric
Satellite COSPAR Date LS Launch Vehicle Remarks
SIRTF (SST, Spitzer) 2003-038A 25.08.2003 CC SLC-17B Delta-7920H