The Spitzer Space Telescope (SST) (formerly the Space Infrared Telescope Facility (SIRTF)) is an infrared space observatory, the fourth and final of NASA's Great Observatories. The duration of the mission will be a minimum of 2.5 years, with 5 or more optimal. In keeping with NASA tradition, the telescope was renamed after successful demonstration of operation, on December 18, 2003. Unlike most telescopes which are named after famous deceased astronomers by a board of scientists, the name for SIRTF was obtained from a contest open only to children (to the delight of science educators).
The name chosen was after Dr. Lyman Spitzer, Jr.. He was one of the 20th century's most influential scientists, and in the mid-1940s, he first proposed placing telescopes in space.
SST was launched on Monday 25 August 2003 at 1:35:39 (EDT) from Cape Canaveral Air Force Station on a Delta 7920H ELV rocket. It will follow a rather unusual orbit, heliocentric instead of geocentric, following earth in its orbit. The primary mirror is 85 cm in diameter, f/12 and made of Beryllium and cooled to 5.5 K. The satellite contains several instruments, that will allow it to perform imaging and photometry from 3 to 180 microns, spectroscopy from 5-40 microns and spectrophotometry from 5-100 microns.
Previous infrared observations had been made by both space-based and ground-based observatories. Ground-based observatories have the draw back that at infrared wavelengths or frequencies, both the Earth's atmosphere and the telescope itself will radiate (glow) strongly. This necessitates lengthy calibrations of all images and will decrease the ability to detect faint objects. Previous space-based satellites (such as IRAS, the Infrared Astronomical Satellite) were operational during the 1980's and great advances in astronomical technology have been made since then.
The first images taken by SST were designed to show off the abilities of the telescope and showed a a glowing stellar nursery; a swirling, dusty galaxy; a disc of planet-forming debris; and organic material in the distant universe. While some time on the telescope is reserved for participating institutions and crucial projects, astronomers around the world also have the opportunity to submit proposals for observing time. Important targets will include forming stars (young stellar objects, or YSOs), planets, and other galaxies. Images are freely available for educational and journalistic purposes.