Spitzer

A graphic image that represents the Spitzer mission

Full Name: Spitzer Space Telescope

Phase: Operating

Launch Date: August 25, 2003

Mission Project Home Page: http://www.spitzer.caltech.edu/

Program(s): Cosmic Origins

Spitzer - Seven Sisters
The Seven Sisters, also known as the Pleiades star cluster, seem to float on a bed of feathers in a new infrared image from NASA's Spitzer Space Telescope. Clouds of dust sweep around the stars, swaddling them in a cushiony veil.
The Pleiades, located more than 400 light-years away in the Taurus constellation, are the subject of many legends and writings. Greek mythology holds that the flock of stars was transformed into celestial doves by Zeus to save them from a pursuant Orion. The 19th-century poet Alfred Lord Tennyson described them as "glittering like a swarm of fireflies tangled in a silver braid."
The new infrared image from Spitzer highlights this "tangled silver braid." This spider-web-like network of filaments, colored yellow, green and red in this view, is made up of dust associated with the cloud through which the cluster is traveling. The densest portion of the cloud appears in yellow and red, and the more diffuse outskirts are shown in green hues. One of the parent stars, Atlas, can be seen at the bottom, while six of the sisters are visible at top. Additional stars in the cluster are sprinkled throughout the picture in blue.
Image Credit: NASA/JPL-Caltech

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 will continue its IR observations.  These two working channels will 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 will be able to see through the dust that permeates our galaxy and blocks visible-light views. This “warm” mission is projected to last about two years.

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.