What is the Spitzer Space Telescope?

One of NASA's current astronomy projects is the Spitzer Space Telescope (formerly called SIRTF). The Spitzer Space Telescope was launched into space in August 2003. to study our solar system, our galaxy, and the universe. Spitzer will be the fourth and final observatory in NASA's family of Great Observatories. It will join the Hubble Space Telescope (HST), the Compton Gamma-Ray Observatory (CGRO), and the Chandra X-Ray Observatory (CXO) in space.
These observatories are each a little different because they look at different kinds of light. The light that we can see with our eyes is called visible light (HST looks at visible light, too). There are also other kinds of light coming from the stars and galaxies in the Universe. The Spitzer Space Telescope looks at what is called infrared light. To discover infrared light for yourself, check out the Herschel experiment (William Herschel was the first person to discover that there were kinds of light other than visible light).

The challenge for the Spitzer Space Telescope (and for all infrared telescopes) is to measure weak infrared signals from space. To appreciate the difficulty, think of what happens when you are outdoors on a sunny day. You are likely to feel the warmth of the Sun on your skin, right? Now imagine trying to feel the warmth of distant stars! This is what astronomers do with infrared telescopes - measure the heat from distant objects in space like stars, dust, and galaxies.
What is the Purpose of the Spitzer Space Telescope?  

What is the Purpose of the Spitzer Space Telescope? What Will the Spitzer Space Telescope Do? Building the Spitzer Space Telescope