Orbiting Astronomical
Observatories (OAO)
Orbiting Astronautical Observatory
Credits - NASA
Credits - NASA
The Orbiting Astronomical Observatories (OAO-1, -2, and -3)
were a series of early astronomical satellites launched by the National
Aeronautics and Space Administration from 1966 through 1972. Its objectives
were to provide astronomical data in the ultraviolet (UV) and x-ray
wavelengths.
OAO-1 was successfully launched on April 8, 1966, from Cape
Canaveral, but it suffered a battery malfunction and failed 1-1/2 hours into
the mission.
OAO-2 was successfully launched on December 7, 1968. It
carried 11 telescopes, and performed x-ray, UV, and infrared (IR) observations
of stars until February 1973. Its instruments detected a supernova in May 1972,
as well as the first UV radiation from the center of the Andromeda Galaxy. It
was the heaviest satellite orbited up to that time.
OAO-B, on November 30, 1970, failed to achieve Earth orbit,
and fell into the Atlantic.
OAO-3 was successfully launched on August 21, 1972, and was
later named Copernicus. It returned data until early 1981
on the birth, death, and life cycles of stars. OAO-3 was a collaborative effort
between the United States and Great Britain. The main experiment on board was
the 450-kilogram Princeton Experiments Package that included an 80-cm UV
telescope, the largest telescope up to that time. It also carried an x-ray
astronomy experiment sponsored by the University College of London that studied
stellar x-ray sources and x-ray absorption in interstellar space. OAO-3
was used primarily in the study of UV radiation from interstellar gas and dust
and from stars near the edges of the Milky Way.