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The objectives of the OSO satellite series were to perform solar physics experiments above the atmosphere during a complete solar cycle and to map the celestial sphere for direction and intensity of UV light, X-rays, and gamma radiation. The OSO 1 was the first satellite to have pointed instruments and onboard tape recorders for data storage. The OSO 1 platform consisted of a sail section, which pointed two experiments continuously toward the sun, supplying power to the experiments from the solar batteries and rechargeable chemical batteries; and a wheel section, which spun about an axis perpendicular to the pointing direction of the sail and carried seven experiments. Attitude adjustment was performed by gas jets. Data were simultaneously recorded on tape and transmitted by FM telemetry. A command system provided for 10 ground-based commands. The spacecraft performed normally until the second onboard tape recorder failed May 15, 1962. The spacecraft provided real-time data until May 1964, when the power cells failed. For more information, see A. W. L. Ball, Spaceflight, v. 12, p. 244, 1970.

It is believed that the solar cells were damaged by the Starfish Prime high-altitude nuclear test, and that this led to the eventual failure of the spacecraft power cells in May 1964.

Starfish Prime

Starfish Prime was an American high-altitude nuclear test that took place on 9 July 1962. Launch took place from Johnston atoll in the Pacific Ocean (about 1330 km southwest of Honolulu) at 8:46:28 UT on 9 July 1962 (10:46:28 pm, 8 July local time) on a Thor rocket carrying a W49 thermonuclear warhead. Detonation of the warhead occurred at 09:00:09 UT on 9 July (11:00:09 pm local time, 8 July) at an altitude of 400 km. Total yield was 1.4 megatons. The explosion, occurring at a geomagnetic latitude 10.5 degrees, generated an electromagnetic pulse and generated large amounts of charged particles. These had the effect of damaging many operating satellites, both at the time of the blast and later, as the energetic particles remained trapped in the Earth's magnetic field, forming an artificial radiation belt that persisted for many weeks after the explosion. These damaged satellites include TRAAC, Transit-4B, Ariel 1, Cosmos 5, Telstar 1, Explorers 14 and 15, and possibly Injun 1, OSO-1, Alouette 1, and ANNA-1B.

Alternate Names

  • 00255
  • 1962 Zeta 1
  • OSO-A
  • OSO1
  • S 16

Facts in Brief

Launch Date: 1962-03-07
Launch Vehicle: Thor-Delta
Launch Site: Cape Canaveral, United States
Mass: 207.7 kg

Funding Agency

  • NASA-Office of Space Science Applications (United States)


  • Planetary Science
  • Space Physics
  • Solar Physics
  • Astronomy

Additional Information

Questions and comments about this spacecraft can be directed to: Dr. H. Kent Hills



NameRoleOriginal AffiliationE-mail
Mr. John C. LindsayProject ManagerNASA Goddard Space Flight Center
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