Spitzer Space Telescope
The Spitzer Space Telescope (formerly SIRTF, the Space Infrared Telescope
Facility) was launched into space by a Delta rocket from Cape Canaveral, Florida
on 25 August 2003. During its 2.5-year mission, Spitzer will obtain images and
spectra by detecting the infrared energy, or heat, radiated by objects in space
between wavelengths of 3 and 180 microns (1 micron is one-millionth of a meter).
Most of this infrared radiation is blocked by the Earth's atmosphere and cannot
be observed from the ground.
Consisting of a 0.85-meter telescope and three cryogenically-cooled science
instruments, Spitzer is the largest infrared telescope ever launched into space.
Its highly sensitive instruments give us a unique view of the Universe and allow
us to peer into regions of space which are hidden from optical telescopes. Many
areas of space are filled with vast, dense clouds of gas and dust which block
our view. Infrared light, however can penetrate these clouds, allowing us to
peer into regions of star formation, the centers of galaxies, and into newly
forming planetary systems. Infrared also brings us information about the cooler
objects in space, such as smaller stars which are too dim to be detected by
their visible light, extrasolar planets, and giant molecular clouds. Also, many
molecules in space, including organic molecules, have their unique signatures in
the infrared.
Because infrared is primarily heat radiation, the telescope must be cooled to
near absolute zero (-459 degrees Fahrenheit or -273 degrees Celsius) so that it
can observe infrared signals from space without interference from the
telescope's own heat. Also, the telescope must be protected from the heat of the
Sun and the infrared radiation put out by the Earth. To do this, Spitzer carries
a solar shield and will be launched into an Earth-trailing solar orbit. This
unique orbit places Spitzer far enough away from the Earth to allow the
telescope to cool rapidy without having to carry large amounts of cryogen
(coolant). This innovative approach has significantly reduced the cost of the
mission.
Spitzer will be the final mission in NASA's Great Observatories Program - a
family of four orbiting observatories, each observing the Universe in a
different kind of light (visible, gamma rays, X-rays, and infrared). Other
missions in this program include the Hubble Space Telescope (HST), Compton
Gamma-Ray Observatory (CGRO), and the Chandra X-Ray Observatory(CXO). Spitzer is
also a part of NASA's Astronomical Search for Origins Program, designed to
provide information which will help us understand our cosmic roots, and how
galaxies, stars and planets develop and form.