The Space Infrared Telescope Facility (SIRTF) is a spacecraft observatory made for studying objects seen in the infrared band of the light spectrum. SIRTF is the fourth spacecraft of the “Great Observatories “. The three before it are the Hubble Space Telescope, launched by the space shuttle in 1990; the Gamma Ray Observatory, launched in 1991; and the Chandra X-Ray Observatory, launched in 1999.
Each of the Great Observatories observes different colors of light that cannot be viewed from the Earth’s surface, and each serves a different function.
SIRTF has been on the drawing board since 1983 and it was originally set for launch in 1990. The design of SIRTF kept evolving and now we have something quite unique.
Unlike most astronomical spacecraft SIRTF will not be orbiting the Earth. Instead, it will be put into orbit around the sun.
“SIRTF will be following the Earth around the sun, kind of like a faithful puppy dog,” astronomer Michael Werner said. The solar orbit increases the lifetime of the spacecraft.
SIRTF will gradually lag further and further away from the Earth until it’s too far to be detected. But in about six decades the Earth will “catch up” with SIRTF, like a race car lapping another race car.
SIRTF observes in the infrared light band and its scientists joke that SIRTF looks at the “cold, the dark, and the dirty.”
The imaging system is extreme sensitive in that it can be used to examine the stellar clouds and dust or it can be adjusted to peer through the clouds and dust.
SIRTF’s detectors are incredibly sensitive. If you could put a common household television remote control in deep space SIRTF could detect it at a distance of 25,000 miles.
Many of SIRTF’s scientists have been working on the project for parts of three decades. One astronomer noted that they should have realized the project was jinxed when NASA’s announcement of opportunity in 1983 was released on a Friday the 13th.
To detect incredibly faint objects at the edge of the universe SIRTF’s cameras are bathed in liquid Helium just a couple of degrees above absolute zero. The spacecraft has 95 gallons (360 liters) of Helium, enough to last about five and a half years
The beauty of this Great Observatory is that it completes the the spectrum range that we can now study. Since each Great Observatory can examine a different range of light these telescopes can be used in conjunction with the others. We can now take four passes at a far object, one with each scope, and see it on all wavelengths.
Source: CNN.com
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