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OSO 8 [Hughes]

The objectives of the OSO (Orbital Solar Observatory) satellite series were to perform solar physics experiments above the atmosphere during a complete solar cycle and to map the entire celestial sphere for direction and intensity of UV light, X-ray radiation, and gamma-ray radiation. The OSO 8 platform consisted of a sail section, which pointed two experiments continually toward the sun, and a wheel section, which spun about an axis perpendicular to the pointing direction of the sail and carried five experiments. Gas jets and a magnetic torquing coil performed attitude adjustment. Pointing control permitted the pointed experiments to scan the region of the solar disk in a 40- by 40-arc-min to 60- by 60-arc-min raster pattern. In addition, the pointed section was capable of being commanded to select and scan a 1- by 1-arc-min or 5- by 5-arc-min region anywhere on the solar disk. The spacecraft had a mission life of more than a year, but exceeded that by transmitting data until Sept. 26, 1978, outliving all other OSOs by at least six months.

OSO 8 carried following instruments:

  • High-Resolution Ultraviolet Spectrometer Measurements
  • Chromosphere Fine-Structure Study
  • High-Sensitivity Crystal Spectroscopy of Stellar and Solar X-rays
  • Mapping X-Ray Heliometer
  • Soft X-ray Background Radiation Investigation
  • Cosmic X-Ray Spectroscopy
  • High-Energy Celestial X-rays
  • EUV From Earth and Space
Nation: USA
Type / Application: Solar observatory
Operator: NASA
Contractors: Hughes
Configuration: HS-331
Power: Solar cells, batteries
Lifetime: 1 year
Mass: 1066 kg
Orbit: 539 km × 553 km, 32.9
Satellite COSPAR Date LS Launch Vehicle Remarks
OSO 8 (OSO I) 1975-057A 21.06.1975 CC LC-17B Delta-1910
OSO J - cancelled
OSO K - cancelled