The First Orbiting Solar Observatory One (OSO 1) was the initial member a series of OSO missions. Launched on 7 March 1962, the 200 kg spacecraft had a 9-sided spinning wheel section 1.2 m in diameter joined onto a fan-shaped sail section. It was put into a roughly circular orbit at ∼575 km altitude, 32.8° inclination. It’s primary mission objectives were to measure the solar electromagnetic radiation in the UV, X-ray, and gamma-ray regions. Secondarily, it was to investigate dust particle in space. Data transmission ended on 6 August 1963. The satellite reentered the Earth’s atmosphere 8 October 1981.
Mission Characteristics
Lifetime
Mar 1962–Aug 1963
Special Features
There were a number of X-ray and gamma-ray experiments aboard OSO 1 for performing solar observations. One instrument, however, the University of Minnesota Gamma Ray Experiment, was designed to provide preliminary measurements of the intensity and directional properties of low-energy gamma-rays in space.
Lifetime
Mar 1962–Aug 1963
Special Features
There were a number of X-ray and gamma-ray experiments aboard OSO 1 for performing solar observations. One instrument, however, the University of Minnesota Gamma Ray Experiment, was designed to provide preliminary measurements of the intensity and directional properties of low-energy gamma-rays in space.
Payload
Instrument
Characteristic
Details
University of Minnesota Gamma Ray Experiment
Energy Range
50 keV – 3 Mev (total)
For the 50–150 keV range, a NaI(Tl) scintillation crystal monitored radiation through a lead shield. The detector operating in the 0.3–1.0 MeV and 1.0–3.0 MeV energy regions used two scintillators connected as a Compton coincidence telescope.
University of Minnesota Gamma Ray Experiment
Energy Range
50 keV – 3 Mev (total)
For the 50–150 keV range, a NaI(Tl) scintillation crystal monitored radiation through a lead shield. The detector operating in the 0.3–1.0 MeV and 1.0–3.0 MeV energy regions used two scintillators connected as a Compton coincidence telescope.
Science Highlights
The gamma-ray experiment on OSO 1 produced a measurement of the extraterrestrial gamma-ray flux between 0.5–3.0 MeV, and an indication of its origin on the celestial sphere. Equally important, this experiment began to define the background problems encountered in gamma-ray astronomy.
