By

Vinay Patel

Background and Facts

• The Spitzer Space Telescope, abbreviated SST, is an infrared observatory and the last of NASA’s Great Observatories.

• It is formerly known as the Space Infrared Telescope Facility (SIRTF).

• The SST was launched August 25, 2003, for a mission estimated to last from a minimum of 2.5 years to 5 or more years.

The SST• Spitzer is the largest infrared

telescope launched into space.

• At 2,090 lbs and worth $800 million, the Spitzer satellite carries a 0.85-meter telescope and three other scientific instruments:– IRAC (Infrared Array

Camera)– IRS (Infrared

Spectrograph)– MIPS (Multiband Imaging

Photometer for Spitzer)

Orbit• The SST follows a rather

unusual orbit. It has a heliocentric orbit rather than a geocentric one, so that it follows the Earth and its orbit around the Sun.

• It is currently drifting off from the Earth at a speed of about 0.1 AU per year.

Infrared’s Use

• Because it uses infrared technology, Spitzer has several advantages that allow astronomers to peer into hidden regions of the Universe.

• Vast, dense clouds of gas and dust, or interstellar dust, fills much of space, blocking our view of visible light. Infrared light, however, can penetrate these clouds, allowing us to see deeper into the universe.

• Infrared light also allows us to see cooler objects across the Universe. Some of these objects are too dim to be seen in visible light, but can be seen using the infrared.

The Mountains of Creation

Protecting the Telescope

• Infrared light, from the Sun, the Earth, and the telescope itself, can affect images created by the telescope.

• Since the instruments on Spitzer are very sensitive (about 1,000 times more sensitive than previous instruments), the telescope must operate at a temperature near absolute zero.

• To keep Spitzer operating at a low temperature, Spitzer is cryogenically cooled, with a dewar filled with 90 gallons of liquid helium. It also has a solar shield to avoid infrared from the Sun.

The IRAC

The Real IRAC

• The IRAC (Infrared Array Camera) is a four-color (blue, green, yellow, and red) composite of invisible light.

• A galaxy, such as NGC 7311, in the infrared would have brownish red arms, a yellow ring of star formation, and a blue central bulge.

Bibliography

• http://www.ballaerospace.com/sirtf.html• http://en.wikipedia.org/wiki/Spitzer_Space_Telescope• http://www.daviddarling.info/encyclopedia/S/

Spitzer_Space_Telescope.html• http://www.lockheedmartin.com/wms/findPage.do?

dsp=fec&ci=14786&rsbci=0&fti=0&ti=0&sc=400• http://www.spacetoday.org/DeepSpace/Telescopes/

GreatObservatories/SIRTF/SIRTF.html