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Spitzer Space Telescope

Phase: Operating

Launch Date: August 25, 2003

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Program(s):Cosmic Origins

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The Spitzer Space Telescope (formerly SIRTF, the Space Infrared Telescope Facility) was launched into space August 25, 2003. During its cryogenic mission, Spitzer obtained 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, when it was launched Spitzer was the largest infrared telescope in space.  Its highly sensitive instruments provide 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 was 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 was launched into an Earth-trailing solar orbit. This unique orbit places Spitzer far enough away from the Earth to allow the telescope to cool rapidly without having to carry large amounts of cryogen (coolant). This innovative approach significantly reduced the cost of the mission.

 On May 15, 2009, Spitzer used the last of the superfluid helium aboard the spacecraft. The cryogenic mission lasted roughly 5 years and 9 months, allowing over 36,000 hours of science observations to be completed.  The data will delivered to the NASA/IPAC Infrared Science Archive (IRSA), where it is be available for scientists to study. 

The Spitzer spacecraft slowly warmed over the course of a couple of months to a temperature of -404 degree Fahrenheit (-242 Celsius). Using the IRAC instrument 3.6 and 4.5 micron channels which still function at this "warmer" temperature, Spitzer is continuing its IR observations. These two working channels allow Spitzer to still pick up the glow from a range of objects including: asteroids in our solar system, dusty stars, planet-forming disks, gas-giant planets and distant galaxies. In addition, Spitzer can still see through the dust that permeates our galaxy and blocks visible-light views.

Spitzer 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). 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 Cosmic Origins Program, designed to provide information which will help us understand our cosmic roots, and how galaxies, stars and planets develop and form.

Science Highlights

In more than a decade of operation, Spitzer has contributed important new discoveries about our universe. Some of the science results discovered by Spitzer include:

  • First to detect light coming from a planet outside our solar system.
  • Generating a complete census of forming stars in nearby clouds.
  • Making a new and improved map of the Milky Way's spiral-arm structure.
  • Determining that the Milky Way galaxy has a more substantial bar structure across its core than previously recognized.
  • Discovering the largest ring around Saturn.
  • Collaborating with the Hubble Space Telescope to discover that the most distant galaxies known are more massive and mature than expected.
  • Discovering carbon molecules, known as "buckyballs" in space for the first time.
  • Generated the largest, most detailed infra-red portrait of the Milky Way (with >800,000 snapshots stitched together)

Ring of Stellar Fire
This image from NASA's Spitzer Space Telescope, taken in infrared light, shows where the action is taking place in galaxy NGC 1291. The outer ring, shown in red, is filled with new stars that are igniting and heating up dust that glows with infrared light. The stars in the central area produce shorter-wavelength infrared light than that seen in the ring, and are colored blue.


Last Updated: March 31, 2015

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