The Engineering Design of the Orbiting Astronomical Observatory

The Orbiting Astronomical Observatory (OAO) is designed to provide an accurately stabilized, unmanned platform for astronomical observations from well above the earth's atmosphere. Of primary immediate interest is the observation of stellar radiation in the ultraviolet range, which is severely limited even in balloon experiments because of absorption in the ozone layers. The OAO is a 3600-pound spacecraft that will be placed in orbit by an Atlas Agena D. It can handle optical systems up to 48 inches in diameter, 10 feet in length, weighing 1000 pounds. The key design requirements of the spacecraft are discussed. The reasons behind the configuration are then explained, followed by a discussion of the major subsystems showing how they have been designed to meet the exacting requirements astronomical observation.