The KAO in flight

The Gerard P. Kuiper Airborne Observatory (KAO) was a national facility operated by NASA to support research in infrared astronomy. The observation platform was a highly modified C-141A jet transport aircraft with a range of 6000 nautical miles, capable of conducting research operations up to 45,000 feet (14 km).

The KAO's telescope was a conventional Cassegrain reflector with a 36-inch (91.5 cm) aperture, designed primarily for observations in the 1 to 500 μm spectral range. Its flight capability allowed it to rise above almost all of the water vapor in the earth's atmosphere (allowing observations of infrared radiation, which is blocked before reaching ground-based facilities), as well as travel to almost any point on the earth's surface for an observation.

The KAO made several major discoveries, including the first sightings of the rings of Uranus in 1977 and a definitive identification of an atmosphere on Pluto in 1988. The KAO was used to study the origin and distribution of water and organic molecules in regions of star formation, and in the vast spaces between the stars. Kuiper astronomers also studied the disks surrounding certain stars that may be related to the formation of planetary systems around these stars.

Peering still deeper into space, KAO astronomers studied powerful far-infrared emissions from the center of our galaxy and other galaxies. Scientists onboard the KAO tracked the formation of heavy elements like iron, nickel, and cobalt from the massive fusion reactions of Supernova 1987A.

The KAO was based at the Ames Research Center at Moffett Field, California (near San Jose, CA). It began operation in 1974 and was retired in 1995. It will be succeeded by the SOFIA in 2005.

http://quest.arc.nasa.gov/lfs/about-kao%5E.html