The Space Infrared Telescope Facility (SIRTF)
was the former name of the Spitzer Space Telescope. It was launched aboard a Delta 2 rocket from Cape Canaveral, Florida at
1:35:39 a.m. eastern daylight time on August 25, 2003. The Space Infrared Telescope Facility (SIRTF)
was renamed as the Spitzer Space Telescope on December 18, 2003
after the late Dr. Lyman Spitzer, Jr.
(Spitzer) is an infrared space telescope which allows astronomers to study everything from asteroids to distant galaxies.
SIRTF is a NASA mission managed by the Jet
SIRTF’s main scientific goals include looking for extra-solar planets, brown dwarfs, protoplanetary disks, infrared-bright galaxies, active galactic nuclei and extremely distant galaxies whose light has been red-shifted well into the infrared. The spacecraft will allow scientists to view the universe as it was billions of years ago and to help them understand how and when the first objects were formed and what their composition is.
The Space Infrared Telescope Facility (SIRTF) spacecraft was placed in heliocentric orbit where the spacecraft slowly moved away from the Earth. This limited the amount of terrestrial infrared radiation
SIRTF (Spitzer) would have to deal with and thus reduce the amount of liquid helium used to keep the telescope’s sensitive instruments cool. An interesting design innovation of the SIRTF
spacecraft was that it was launched ‘warm’ and the outer space environment allowed it to radiatively cool which also reduced the amount of liquid helium required and reduced spacecraft development costs.
The spacecraft’s three instruments are a camera, spectrograph and imaging photometer. The instruments are sensitive to infrared light at wavelengths between 3 and 180 microns.
History of the Space Infrared Telescope Facility (SIRTF)
SIRTF (now called Spitzer) is one of the four original Great Observatory missions. The other three are the
Telescope, Chandra X-Ray Observatory and Compton Gamma Ray Observatory. SIRTF
(Spitzer) does not operate in Earth Orbit like the other three great observatories
Plans for SIRTF date back to the 1970’s, when NASA considered flying an infrared telescope in the space shuttle’s cargo bay on multiple missions. By the mid 1980’s the design had evolved into a free-flying spacecraft to be launched on the space shuttle or a large expendable booster. In the 1990’s the SIRTF design was changed several times due to budget pressures. It was down-sized from a 5700 kg spacecraft that was going to be launched by a Titan 4 to a 750 kg spacecraft that was launched by the Delta 2.
The first images from SIRTF were taken shortly after launch as part of a systems check. For the first 60 days after launch SIRTF
underwent a check out period, followed by 30 days of scientific instrument calibration.
The science mission at the time of launch was scheduled to last 2.5 years. The mission has potential to last 5 years and by that time SIRTF
(Spitzer) may deplete its liquid helium which is used for cooling the spacecraft and it may drift too far from the Earth.
On 18 December 2003, NASA Administrator Sean O'Keefe announced that
NASA's Space Infrared Telescope Facility had been renamed as the
Spitzer Space Telescope. It was named in honour of the late Dr.
Lyman Spitzer Jr., one of the 20th century's most distinguished
scientists. The new name was chosen after an international contest
sponsored by NASA. More than 7,000 names and supporting essays were
submitted, with more than a third coming from outside the United
States. Jay Stidolph, a Canadian resident of Fort Nelson, British
Columbia, submitted the winning entry.
Lyman Spitzer (1914-1997) was the first to propose, in 1946,
placing a large telescope in space to avoid the blurring effects of
Earth's atmosphere. He then devoted the next 50 years of his career
to making this vision a reality. His efforts led to the Hubble Space
Telescope and another successful NASA space telescope -- the
Copernicus satellite. He also made significant contributions to the
fields of stellar dynamics, the interstellar medium and plasma
Please note the
correct abbreviation is SIRTF and not SIRF.
Planet Quest: The Epic Discovery of
Alien Solar Systems by Ken Croswell
Distant Wanderers: The Search for
Planets Beyond the Solar System by Bruce Dorminey
of California Institute of Technology
- Infrared Array Camera for SIRTF:
NASA Announces New Name for Space Infrared
AstronomyNow Magazine, page 9, October 2003 edition.
Picture Source of SIRTF: NASA/JPL-Caltech