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.

Source: NASA website

Last update: 27.09.2009
Contact: gunter.krebs@skyrocket.de
© Gunter Dirk Krebs