The Infrared Astronomical Satellite ( IRAS; Dutch Infra - Rood Astronomical satellit; German infrared astronomical satellite ) was the first space telescope for the medium and far infrared. With his help, the IRAS Catalog of Point Sources, Version 2.0 was created.

IRAS was developed jointly by the U.S., the UK and the Netherlands. The IRAS telescope with a mirror diameter of 60 cm was cooled to suppress its own thermal radiation by liquid helium as a coolant to a temperature 2-5 degrees Kelvin. IRAS was launched on 26 January 1983, was to exhaustion of the coolant on 23 November 1983 in operation. As space observatory above the Earth's atmosphere IRAS was able to observe objects in the sky even at wavelengths that are from out of the ground can not be used by the absorption of the atmosphere. IRAS was in a low sun-synchronous orbit, the satellite is to shield against disturbing heat radiation could constantly turn to the back of the earth and a sun shield the sun.

Main instrument was an array of 62 infrared detectors ( Survey Array) with an almost complete (96% ) was obtained by screening of the sky at wavelengths of 12, 25, 60 and 100 microns with an angular resolution of a few arc minutes. For this purpose, the telescope was performed in a uniform motion along a long strip across the sky. Other instruments were a low-resolution infrared spectrometer for wavelengths 8-23 microns ( Low Resolution Spectrometer, LRS), with about 5000 spectra were obtained, and a photometer for the wavelengths of 50 and 100 microns ( Chopped Photometric Channel, CPC).


The IRAS mission was an important milestone in infrared astronomy. The sky survey and the catalog derived therefrom from over 300,000 sources are still twenty years later important tools of astronomy. Among the most important discoveries include:

  • Comets and they left behind dust lanes
  • Young stars that are still embedded in the gas and dust clouds from which they originated
  • The filamentary ' structure Cirrus' cold dust in the interstellar medium of the Milky Way
  • Galaxies that emit their high produced by many young stars luminosity almost exclusively in the far infrared