Space Infrared Telescope FacilityThe Space Infrared Telescope Facility (SIRTF) consists of a 0.85-meter telescope and three
cryogenically-cooled science instruments. SIRTF is the largest infrared telescope
ever launched into space. Its highly sensitive instruments provide 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, can be identified by their unique infrared signatures.
Because infrared is primarily heat radiation, the telescope is cooled to near absolute zero
(-273 degrees Celsius or -459 degrees Fahrenheit) so that it can observe infrared signals from space
without interference from the telescope's own heat. Also, the telescope is protected from the heat of
the Sun and the infrared radiation put out by the Earth.
SIRTF is in an "Earth-trailing" orbit around the sun. This allows the SIRTF to remain far enough away
from the Earth to allow the telescope to cool rapidy without having to carry large amounts of coolant.
SIRTF is 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). The other missions in this program
are the Hubble Space Telescope (HST), the Compton Gamma-Ray Observatory (CGRO), and
the Chandra X-Ray Observatory (CXO).
SIRTF 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.
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