Prototype unit for an array of cosmic x-ray detectors that flew in the spinning wheel section of the OSO-IV satellite launched in 1967. It was designed to map out non-solar radiation sources as it swept across the sky. The instrument included two photoelectric X-ray detectors based on sodium iodide scintillation crystals as well as one electron and one cosmic-ray detector The experiment was designed and built at American Science and Engineering (AS&E) under the direction of Riccardo Giacconi. This experiment was donated to NASM by AS&E in 2003.
Gift of American Science & Engineering Incorporated.