Spacecraft Classification

An observatory spacecraft does not travel to a destination to explore it. Instead, it occupies an Earth orbit, or a solar orbit, from where it can observe distant targets free of the obscuring and blurring effects of Earth's atmosphere.
NASA's Great Observatories program studies the universe at wavelengths from infra-red to gamma-rays. The program includes four Observatory Spacecraft: the familiar Hubble Space Telescope (HST), the Chandra X-Ray Observatory (CXO, previously known as AXAF), the Compton Gamma Ray Observatory (GRO), and the Spitzer Space Telescope (previously known as SIRTF).

The HST is still operating as of early 2013. GRO has completed its mission and was de-orbited in June 2000. CXO was launched in July 1999 and continues to operate. SIRTF launched in January 2003 and is currently operating. In the coming decades many new kinds of observatory spacecraft will be deployed to take advantage of the tremendous gains available from operating in space.

Our prime example of an observatory spacecraft is the Spitzer Space Infrared Telescope Facility. Click the SIRTF image for details of the observatory spacecraft. Other examples of observatory spacecraft include:

NuSTAR Nuclear Spectroscopic Telescope Array
WISE Wide-field Infrared Survey Explorer
HST Hubble Space Telescope
Chandra X-ray Observatory
Compton Gamma-ray Observatory
IRAS Infrared Astronomical Satellite
NGST Next-Generation Space Telescope
SIM Space Interferometry Mission
Planck Cosmic Background Radiation Field survey
JWST James Webb Space Telescope