Orbiting Astronomical Observatory

Although two OAO missions were failures, the success of the other two increased awareness within the astronomical community of the benefits of space-based observations, and led to the instigation of the Hubble Space Telescope.

The first Orbiting Astronomical Observatory was launched successfully on 8 April 1966, carrying instruments to detect ultraviolet, X-ray and gamma ray emission.

The spacecraft was out of control, so that the solar panels could not be deployed to recharge the batteries that would supply power to the electrical and electronic equipment on board.

The payload fairing did not separate properly during ascent and the excess weight of it prevented the Centaur stage from achieving orbital velocity.

Copernicus operated until February 1981,[7] and returned high resolution spectra of hundreds of stars along with extensive X-ray observations.

Artist's conception of OAO-1 in orbit
Technicians in a clean room check out the OAO 2 before the mission’s 7 December 1968, launch.
Artist's conception of OAO-B in orbit
OAO-3 in the clean room
A flight spare of the grazing incidence mirror built for OAO-3 (Copernicus). The mirror was part of the X-ray telescope built by University College London . It is now held in the collections of the Science Museum, London .