Research topic: Orbiting Astronomical Observatory

Orbiting Astronomical Observatory (OAO), series of four orbiting observatories (see observatory, orbiting ) launched between 1966 and 1972 by the National Aeronautics and Space Administration (NASA) to provide astronomical data in the ultraviolet and X-ray wavelengths filtered out by the earth's atmosphere. Only two of the four launches were successful, however. OAO-2, launched in 1978, which carried two large telescopes in addition to a cluster of four ultraviolet telescopes, four photoelectric telescopes, and a number of spectrometers and other devices, weighed 4,200 lb (1,900 kg) and was... Read more