In the early 1800s, the British astronomer Sir William Herschel discovered that sunlight consisted not only of visible light that we can see with our eyes, but also infrared energy beyond the visible spectrum. This paved the way for astronomers in the 1900s who used special telescopes to survey the skies at infrared wavelengths.
The concept of the Infrared Astronomical Satellite was to take such a telescope and place it in orbit above the interference of Earth's atmosphere. The telescope required a special cooler to bring the temperature of the infrared detector down to a few degrees above absolute zero. This extremely low temperature made the detectors up to a thousand times more sensitive than any before them. The Netherlands was responsible for the spacecraft, while the United States contributed the launch, the infrared telescope and final data handling; the United Kingdom was in charge of satellite operations and preliminary data processing.
Launched on January 25, 1983, from California's Vandenberg Air Force Base on a Delta rocket, the satellite orbited Earth from north to south at an altitude of 900 kilometers (about 563 miles). It operated for 10 months until its coolant was depleted as planned.
The Infrared Astronomical Satellite made many unexpected discoveries. Two of the most significant findings were the discovries of solid material around the stars Vega and Fomalhaut, located some 26 and 22 light-years from Earth, respectively. This strongly suggested the existence of planetary systems around other stars.
Mass: 1,080 kilograms (2,381 pounds)
Science instrument: 57-centimeter-diameter (22.5-inch) infrared telescope
Launch: January 25, 1983
Water Vapor Seen 'Raining Down' On Young Star System (8/29/07)
Camera Eyes Dusty Spirals in Milky Way Center (10/1/02)
