Space-based surveys

Infrared Astronomical Satellite (NASA/Netherlands/United Kingdom): Launched Jan. 25, 1983, this mission conducted the first all-sky survey from space at infrared wavelengths. The satellite circled Earth in a 900-kilometer (559-mile) polar orbit and operated for 10 months before exhausting all of its liquid helium coolant. It mapped 96 percent of the sky in four broad wavelength bands, centered at 12, 25, 60 and 100 microns. The mission detected about 350,000 infrared sources, and its data essentially built the framework for all subsequent infrared observatories. The satellite's most significant discoveries included ultraluminous infrared galaxies, whorls of dust around the star Vega and other stars, six new comets and wisps of warm dusty material called infrared cirrus that pervades our galaxy.

Cosmic Background Explorer (NASA): Launched Nov. 18, 1989, this mission studied both infrared and microwave radiation emitted by remnants of the Big Bang, the cataclysmic event believed to mark the beginning of the physical universe. The mission discovered a diffuse background infrared radiation that is thought to be a remnant of the Big Bang. In addition, it mapped the brightness of the sky at several infrared wavelengths. Using Cosmic Background Explorer data, scientists discovered that cosmic microwave background radiation is not entirely smooth, but instead shows tiny variations in temperature - the seeds that may have led to the formation of galaxies.

Infrared Space Observatory (European Space Agency, with participation of Japan and NASA): The mission, launched Nov. 17, 1995, observed at wavelengths between 2.5 and 240 microns, covering a much wider wavelength range with greater sensitivity and higher resolution than any previous mission. It operated for 2-1/2 years until its liquid helium coolant ran out in May 1998. Its cameras and spectrographs made many detailed observations of objects ranging from nearby comets to distant galaxies. One of the mission's most important observations was the diffuse infrared glow, first discovered by the Cosmic Background Explorer, thought to be the result of a population of extremely distant, ancient galaxies.

Hubble Space Telescope Near Infrared Camera and Multi-Object Spectrometer (NASA): The Near Infrared Camera and Multi-Object Spectrometer is an instrument installed on NASA's Hubble Space Telescope, allowing it to observe using near-infrared light in wavelengths between 0.8 and 2.5 microns (visible light lies between 0.3 and 0.7 microns). The instrument is capable of both imaging and spectroscopy, or analyzing light for signs of chemical elements in the near infrared. It has had success in imaging and studying the close environments and some circumstellar debris discs around nearby stars. The University of Arizona, Tucson operates and manages the instrument for NASA.

James Webb Space Telescope (NASA): With a planned launch in about 2010, this telescope will study objects in both infrared and visible light with extremely high sensitivity and resolution. It will use mid- and near-infrared detectors to provide the best views yet of the sky within this range of wavelengths. The mission is planned to study the early universe and the formation of galaxies, stars and planets. It will also follow up on some of the many anticipated discoveries by the Space Infrared Telescope Facility.

NASA airborne surveys

Kuiper Airborne Observatory: From 1971 to 1995, NASA's Kuiper Airborne Observatory was the world's only airborne telescope devoted exclusively to astronomical research. It observed in the infrared range at wavelengths between 1 and 500 microns. A converted C-141 military cargo plane carried the 91-centimeter-diameter (36-inch) telescope to an altitude of 13.7 kilometers (45,000 feet), thereby greatly reducing the infrared interference from moisture in Earth's atmosphere. The observatory's most notable discoveries were the first sighting of rings around Uranus and an atmosphere around Pluto.

Stratospheric Observatory for Infrared Astronomy (Sofia): The Stratospheric Observatory for Infrared Astronomy incorporates an infrared-sensitive telescope onboard a modified Boeing 747-SP aircraft. The observatory is scheduled to fly in 2004. Astronomers hope to use the airborne telescope to study star birth and death, nebulas and black holes. The project is managed by NASA's Ames Research Center, Moffett Field, CA.

NASA ground-based surveys

Two-Micron Sky Survey (California Institute of Technology): The first infrared survey of the sky from the ground was made at Mount Wilson Observatory in Southern California in the 1960s. It was led by Drs. Robert Leighton and Gerry Neugebauer of the California Institute of Technology in Pasadena. The survey, conducted at a wavelength of 2.2 microns, covered about 75 percent of the sky and produced a catalogue of 5,000 celestial objects.

Two Micron All-Sky Survey (NASA/University of Massachusetts/California Institute of Technology): Using two infrared telescopes, one at Mount Hopkins, Ariz., and the other at Cerro Tololo, Chile, this mission conducted the most thorough high-resolution digital survey of the entire sky, observing nearly 500 million objects. The Arizona telescope began observations in June 1997, while the Chilean telescope began in March 1998. The survey concluded in February 2001, and the data analysis of the full survey is just beginning. The project's major contributions were the detection of hundreds of brown dwarfs, mapping of the Milky Way's structure and dust distribution, charting of the large-scale structure of the nearby universe, observations of galaxies hidden behind the disc of the Milky Way, and discoveries of numerous dust-obscured galaxies and quasars in the distant universe.

Infrared Telescope Facility: NASA's Infrared Telescope Facility is a ground-based, 9.8-feet-wide (3-meter) telescope, designed to be sensitive to infrared wavelengths. The telescope is located at the summit of Mauna Kea in Hawaii, and is managed for NASA by the University of Hawaii Institute for Astronomy, located in Honolulu. The telescope was established in 1979 to provide infrared support of NASA missions such as the Voyager spacecraft to the outer planets, and 50 percent of its observing time remains reserved for study of solar system objects, mainly planets and their moons.