The first orbiting astronomical infrared telescope system Its development and performance

The Infrared Astronomical Satellite (IRAS) was launched on January 25, 1983, and has provided astronomers with their first extended views of the universe in the 8 to 120 micron wavelength region. The infrared telescope system is one of several United States contributions to this international project sponsored by the U.S.A., The Netherlands, and the U.K. This telescope employs four bands of detectors cooled to 2.4 K to achieve a noise equivalent flux density in the 10 to the -18th to 10 to the -19th watts/sq cm range and will operate for approximately eleven months before depletion of its supply of superfluid helium. This paper describes major problems, early flight results, and technical lessons learned during the course of the telescope's development and flight operations.