National Aeronautics and Space Administration

High Energy Astrophysics Observatories

These Web pages describe all the high energy astronomy observatories, or "missions," ever launched, excluding those solely dedicated to observing the Sun. If on the other hand you are interested in cosmic microwave background experiments, please check out this extensive list on the LAMBDA web site.

The links to the left in the menu-bar are dedicated to the most notable past and present X-ray and gamma-ray astronomy missions. The pages for each mission include:

• a mission overview,
• technical information on the instrumentation,
• a bibliography and
• a gallery of images.

They also contain a description of the available data if they are present in the HEASARC archive. Information on other satellites carrying either an X-ray or a gamma-ray telescope is available on the All Missions pages.

Latest News

NICER was launched on a SpaceX Dragon rocket on June 3, 2017 as part of a resupply mission to the ISS More News

Spacecraft Image of the Week

Suzaku Japanese/US x-ray satellite. Lifetime: July 2005 - present

High energy astrophysics is a young discipline, whose history is only a few decades old, and requires space-borne instruments to observe the X-ray and gamma-ray sky.

X-ray Observatories After the rocket experiments during the 1960s, the first X-ray Earth-orbiting explorers were launched in the 1970s (Uhuru, SAS 3, Ariel5) followed in late 1970s early 1980s by larger missions (HEAO-1, Einstein, EXOSAT, and Ginga). Their scientific outcome, in particular the first X-ray images taken by Einstein, lifted X-ray astronomy into the mainstream of astronomical research. It is now known that nearly every astronomical object from nearby comets to distant quasars emits X-rays. In the 1990s the ROSAT survey detected more than 100,000 X-ray objects, the ASCA mission made the first sensitive measurements of the X-ray spectra from these objects, and RXTE studied their timing properties. The late 1990's launch of the Chandra and XMM-Newton observatories brought high-resolution imaging and high-throughput capability to X-ray astronomy. These missions, combined with Suzaku/Astro-E2, launched in 2005, have opened new and exciting horizons in the journey of the X-ray astronomy exploration.

Gamma-Ray Observatories SAS 2 and Cos B, launched in the 1970s, made the first surveys of the gamma-ray sky, followed by the Compton Gamma-ray Observatory in 1990 and more recently by INTEGRAL in 2002. Blazars, pulsars, and many unidentified sources in our galaxy are the gamma-ray emitters. Fermi (formerly GLAST), the latest gamma-ray observatory, is expected to resolve the diffuse emission and make an all-sky survey with higher angular and energy resolution. The mysterious gamma-ray bursts (GRBs) discovered in the late 1960s by the Vela satellite, were shown to be the most powerful explosions in the Universe and isotropically distributed, thanks to the rapid response capability of BeppoSAX and the all-sky monitoring of CGRO. Swift, launched in November 2004, is providing data on the GRBs prompt emission and their afterglows to allow the most comprehensive study on GRBs and determine their origin.

Further Reading Why are X-ray and gamma-ray observatories in space? A Brief History of High-Energy (X-ray & Gamma-Ray) Astronomy (in the form of a reverse chronology) A brief history of X-ray and gamma-ray astronomy. Bibliography on X-ray and gamma-ray astronomy. Books: "Astronomy from Space" by John K. Davies, 1997, Praxis Publishing Ltd. "X-ray Detectors" by George Fraser, Cambridge Astrophysics series.