This is an engineering prototype of Orbiting Solar Observatory 1 (OSO-1), the earliest of the spin stabilized scientific satellites. This object touted the ability of the satellite's systems to search out and lock onto a "solar" image. It demonstrated the sun-pointing capabilities of the satellite. It contains actual instruments in the octagonal spin section, and mock-ups in the pointed section, save for the photoelectric eye block. Ball Aerospace Systems Division restored this engineering prototype in 1982.
Transferred from the NASA to the Museum in 1981.