Solar Radiation and Thermospheric Satellite

Solar Radiation and Thermospheric Satellite (SRATS), also knows as Taiyo ("Sun" in Japanese) or Shinsei-3,^[1] was a space probe developed by the Institute of Space and Astronautical Science (ISAS) at the University of Tokyo. The probe was launched on February 24, 1975, from Kagoshima Space Center by M-3C-2 rocket. Its mission was focused on upper atmospheric physics, X-ray and UV solar radiation, and the Earth's ionosphere. Taiyo completed its mission before re-entering Earth's atmosphere on June 29, 1980.^[2]

The satellite had a shape of octagonal cylinder (or prism), weighing 86 kg. It orbited the Earth in an elliptical orbit with a periapsis of 260 km and an apoapsis of 3,140 km, at a 32-degree inclination. The satellite's primary goal was to investigate solar X-rays, ultraviolet radiation, and the distribution of ions and electrons in the Earth's upper atmosphere.^[2][3]

Taiyo had seven science instruments:^[2]

• Solar X-Ray Detector (SXR): Designed to observe solar X-rays in two energy ranges (5.9-9.5 keV, 9.5-11.5 keV) and measure charged particles near the Earth's radiation belts.
• Lyman-alpha Radiation Monitor (SXU): Measured solar hydrogen Lyman-alpha radiation to study the Sun's chromosphere.
• Geocoronal and Middle Ultraviolet Radiometers (GMV): This system combined the Middle Ultraviolet Radiometer (MUV), which measured reflected solar light from atmospheric ozone, and the Vacuum Ultraviolet Photon Counter (GUV), which analyzed geocoronal emissions.
• Bennett Ion Mass Spectrometer (CPI): Examined ion composition in the upper atmosphere, identifying H+, He+, and O+ ions.
• Retarding Potential Analyzer (RPA): Measured ion density and temperature using voltage sweeps across ion traps.
• Electron Temperature Probe (TEL): Recorded electron temperature variations, capable of measuring up to 4000 K.
• Gyro-Plasma Probe (IMP): Analyzed electron density distribution through high-frequency impedance measurements.

• Hirao, Kunio (1975). "The TAIYO Mission". J.Geomag,Geoelectr. 27 (4): 265–270. doi:10.5636/jgg.27.265. Retrieved 22 October 2024.
• Hirao, K. (1 January 1976). Results of observations made by the SRATS (solar radiation and thermospheric structure) satellite. Space Research Xvi (Report). p. 235. Bibcode:1976spre.conf..235H. Retrieved 22 October 2024.
• Matsuoka, Masaru; Nagai, Fukuo; Ohki, Ken-ichiro (1975). "A solar X-ray detector aboard "TAIYO"". Journal of Geomagnetism and Geoelectricity. 27 (4): 271–277. doi:10.5636/jgg.27.271.
• Oshio, Takanori; Masuoka, Toshio; Higashino, Ichiro; Watanabe, Norihiko (1975). "An intensity monitor for solar hydrogen Lyman-.ALPHA. radiation (TAIYO SXU)". Journal of Geomagnetism and Geoelectricity. 27 (4): 279–294. doi:10.5636/jgg.27.279.
• Tohmatsu, Takao; Suzuki, Katsuhisa; Ogawa, Toshihiro (1975). "The atmospheric UV instrumentation for the satellite "TAIYO"". Journal of Geomagnetism and Geoelectricity. 27 (4): 295–301. doi:10.5636/jgg.27.295.
• Iwamoto, Iwao; Suitz, Takeshi; Fugono, Nobuyoshi (1975). "The Bennett ion mass spectrometer aboard "TAIYO" (CPI)". Journal of Geomagnetism and Geoelectricity. 27 (4): 303–310. doi:10.5636/jgg.27.303.
• Miyazaki, Shigeru (1975). "The retarding potential analyzer aboard the satellite TAIYO". Journal of Geomagnetism and Geoelectricity. 27 (4): 311–320. doi:10.5636/jgg.27.311.
• Oyama, Koh-ichiro; Hirao, Kunio (1975). "Electron temperature probe experiments on the satellite "TAIYO"". Journal of Geomagnetism and Geoelectricity. 27 (4): 321–330. doi:10.5636/jgg.27.321.
• Oya, Hiroshi; Morioka, Akira (1975). "Instrumentation and observations of gyro-plasma probe installed on TAIYO for measurement of ionospheric plasma parameters and low energetic particle effects". Journal of Geomagnetism and Geoelectricity. 27 (4): 331–361. doi:10.5636/jgg.27.331.