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SRATS (Taiyo)


SRATS (Solar Radiation and Thermospheric Satellite) was an aeronomy research satellite. It had an octagonal column form (75 cm in diameter and 65 cm in height), in which the experiment instruments were mounted. The satellite was spin stabilized in a rolling wheel mode by a geomagnetic attitude control system. Four plasma probes were extended perpendicular to the spin axis by 0.5-m metallic booms. Power at an average rate of 15 W was provided by 6000 silicon n-p solar cells. The objectives of the satellite were to study the ionosphere systematically by simultaneously observing solar ionizing radiations (hydrogen Lyman-Alpha and X-rays), the ultraviolet albedo of the earth, positive ion composition, and plasma parameters such as electron and ion densities and temperatures in the ionosphere.

Instruments carried:

  • Solar X-Ray Monitor
  • Hydrogen Lyman-Alpha
  • Geocoronal UV Glow and Earth UV Albedo
  • Electron Temperature
  • Retarding Potential Analyzer
  • Ionic Composition
  • Electron Density Measurement


Nation: Japan
Type / Application: Research, Aeronomy, Ionospheric
Operator: ISAS
Power: Solar cells, batteries
Mass: 86 kg
Orbit: 249 km × 3129 km, 31.54
Satellite COSPAR Date LS Launch Vehicle Remarks
SRATS (Taiyo) 1975-014A 24.02.1975 Ka LP-M M-3C