Country of Origin: United States of America
3-D Test: 34 x 34 x 34cm (13 3/8 x 13 3/8 x 13 3/8 in.)
Casing - aluminum
Contents - aluminum, glass optics, electronics
Backup (designated "Flight Unit No. 1") for the solar X-ray and Lyman alpha detector unit that was flown in 1967 on the Orbiting Solar Observatory 4. Both detectors were designed and built at the Naval Research Laboratory (NRL) and were part of the spin section on OSO-4, studying geocoronal characteristics and monitoring solar x-rays. The shape of the instrument is reminiscent of the compartment assigned to it in the spin section. The artifact was transferred from NRL in NASM in 1992.
Transferred from the Naval Research Laboratory