BATSE (Burst and Transient Source Experiment)

A high-energy astrophysics “experiment” used to investigate gamma-ray bursts (GRBs). BATSE consisted of eight detectors that were mounted on the corners of NASA’s Earth-orbiting Compton Gamma-Ray Observatory, whose mission ended in 2000.

BeppoSAX

A space-based X-ray observatory built and operated by the Italian Space Agency and the Netherlands Agency for Aerospace Programs. BeppoSAX has been instrumental in identifying and locating gamma-ray bursts.

Chandra X-Ray Observatory

A space-based X-ray observatory; also known as the Advanced X-ray Astrophysics Facility (AXAF). Chandra is designed to observe X-rays from high-energy regions of the universe, such as hot gas in the remnants of exploded stars. The satellite was launched and deployed in July 1999.

Compton Gamma-Ray Observatory (CGRO)

A space-based observatory that collected high-energy gamma-ray light from celestial objects. The Compton satellite consisted of the BATSE, COMPTEL, EGRET, and OSSE instruments. Astronauts aboard the space shuttle Atlantis deployed the CGRO into low-Earth orbit in April 1991. The satellite plunged into the Pacific Ocean in June 2000.

Hubble Space Telescope (HST)

An orbiting telescope that collects light from celestial objects in visible, near-ultraviolet, and near-infrared wavelengths. The telescope was launched April 24, 1990 aboard the NASA Space Shuttle Discovery. The 12.5-ton (11,110-kg), tube-shaped telescope is 13.1 m (43 ft) long and 4.3 m (14 ft) wide. It orbits the Earth every 96 minutes and is mainly powered by the sunlight collected by its two solar arrays. The telescope’s primary mirror is 2.4 m (8 ft) wide. The telescope is operated jointly by the National Aeronautics and Space Administration (NASA) and the European Space Agency (ESA). HST is one of the many NASA Origins Missions, which include current satellites such as the Far Ultraviolet Space Explorer (FUSE) and future space observatories such as the James Webb Space Telescope (JWST).

International Ultraviolet Explorer (IUE)

The longest operating (1978—1996) and most productive ultraviolet space observatory launched into a high geosynchronous orbit.

Keck Observatory

Two telescopes known as the world's largest optical and infrared telescopes, jointly operated by the California Institute of Technology and the University of California. The telescopes comprise the W.M. Keck Observatory and are located on the summit of Hawaii's dormant Mauna Kea volcano.

Kitt Peak Observatory

The world’s largest collection of telescopes, located high above the Sonora Desert in Arizona. Eight astronomical research institutions share the 22 optical and two radio telescopes at Kitt Peak. The National Optical Astronomy Observatories oversee site operations at the observatory.

Robotic Optical Transient Search Experiment (ROTSE)

A terrestrial telescope that searches for the optical counterparts of gamma-ray bursts. When orbiting satellites detect a gamma-ray burst, ROTSE begins searching for its visible-light afterglow. ROTSE-I (an array of four electronic telephoto cameras) and ROTSE-II (a set of identical telescopes) are located in Los Alamos, New Mexico.

Space Infrared Telescope Facility (SIRTF)

A space-borne infrared telescope that will study planets, comets, stars, galaxies, and other celestial objects. NASA plans to launch SIRTF in December 2002 on a Delta rocket. SIRTF represents the fourth and final satellite in NASA’s Great Observatories program, which includes the Hubble Space Telescope and the Chandra X-Ray Observatory.

Vela Satellite

Launched by the U.S. in the 1960s to monitor the Limited Nuclear Test Ban Treaty. The satellite’s mission was to detect the gamma rays produced during nuclear blasts. Although not intended for astronomical studies, the Vela satellite provided useful celestial data, detecting an unexpected blast of cosmic gamma radiation in 1967. The satellite discovered several other gamma-rays bursts during the years of the Vela project, which ceased operation in 1979.

Very Large Array (VLA)

One of the world’s premier radio observatories, consisting of 27 antennas arranged in a huge “Y” pattern. The VLA spans up to 22 miles (36 km) across, which is roughly one and a half times the size of Washington, D.C. Each antenna is 81 feet (25 meters) in diameter. Located in Socorro, New Mexico, the telescopes work in tandem to produce a sharper image than any single telescope could record.