This is a 1/24th-scale model of the eighth and last in the highly successful series of Orbiting Solar Observatories launched in the 1960s and early 1970s. OSO-I, also known as OSO 8, was placed into a 345-mile height circular orbit on June 21, 1975 from a Delta launch vehicle. Similar to the rest of the series, but of larger dimensions, it consisted of a cylindrical base that rotated, in this case, at about 6 rpm, to stabilize the vehicle, and was topped by a non-spinning stabilized upper section. That structure, called the "sail", carried several "pointed" instruments as well as the solar cells and was kept oriented towards the sun. The primary objective of OSO 8 was to obtain data on radiation from the upper reaches of the sun's corona. The rotating base contained four experiments that observed cosmic X-ray sources. The satellite continued to provide scientific data through September 30, 1978.
The spacecraft was built by Hughes Space and Communications who donated this scale model to NASM in 1975.
This object is not on display at the National Air and Space Museum. It is either on loan or in storage.