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Explorer 14



Explorer 14 was a spin-stabilized, solar-cell-powered spacecraft instrumented to measure cosmic-ray particles, trapped particles, solar wind protons, and magnetospheric and interplanetary magnetic fields. It was the second of the S 3 series of spacecraft, which also included Explorers 12, 15, and 26. A 16-channel PFM/PM time-division multiplexed telemeter was used. The time required to sample the 16 channels (one frame period) was 0.323 s. Half of the channels were used to convey eight-level digital information, and the others were used for analog information. During ground processing of the telemetered data, the analog information was digitized with an accuracy of 1/100th of full scale. One analog channel was subcommutated in a 16-frame-long pattern and was used to telemeter spacecraft temperatures, power system voltages, currents, etc. A digital solar aspect sensor measured the spin period and phase, digitized to 0.041 s, and the angle between the spin axis and sun direction to about 3-deg intervals. The spacecraft functioned well except for the period from January 10 to 24, 1963, and after August 11, 1963, when the encoder malfunctioned terminating the transmission of usable data. Good data were recorded for approximately 85% of the active lifetime of the spacecraft. The spacecraft was coning (37-deg maximum half-angle) until January 10, 1963. After January 24, 1963, it was spin-stabilized at a rate of 10 rpm. This rate slowly decreased to 1 rpm on July 8, 1963. Initially, the local time of apogee was 0700 h.

The encoder malfunction was believed to be due to the exposure to radiation remaining from the Starfish Prime high-altitude nuclear test of 9 July 1962.

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 large quantities 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

  • 00432
  • 1962 Beta Gamma 1
  • EPE-B
  • Explorer14
  • S 3A

Facts in Brief

Launch Date: 1962-10-02
Launch Vehicle: Thor-Delta
Launch Site: Cape Canaveral, United States
Mass: 40 kg

Funding Agency

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


  • Space Physics

Additional Information

Questions and comments about this spacecraft can be directed to: Dr. John F. Cooper



NameRoleOriginal AffiliationE-mail
Dr. Frank B. McDonaldProject ScientistNASA Goddard Space Flight Center
Mr. Paul G. MarcotteProject ManagerNASA Goddard Space Flight Center
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