Orbiting Astronomical Observatory - OAO-3 (Copernicus)

OAO-3 (Copernicus)

OAO-3 was launched on 21 August 1972, and proved to be the most successful of the OAO missions. It was a collaborative effort between NASA and the UK's Science and Engineering Research Council, and carried an X-ray detector built by University College London's Mullard Space Science Laboratory in addition to an 80 cm UV telescope built by Princeton University. After its launch, it was named Copernicus to mark the 500th anniversary of the birth of Nicolaus Copernicus.

Copernicus operated until February 1981, and returned high resolution spectra of hundreds of stars along with extensive X-ray observations. Among the significant discoveries made by Copernicus were the discovery of several long-period pulsars, with rotation times of many minutes instead of the more typical second or less.