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S 55B



This spacecraft, also known as Explorer 16, was the second in the series of micrometeoroid satellites orbited by NASA. Its purpose was to obtain data on the near-earth meteoroid environment, thus providing an accurate estimate of the probability of penetration in spacecraft structures by meteoroids and allowing a more confident definition of the relationship between penetration flux and material thickness to be derived. The cylindrically shaped spacecraft, about 61 cm in diameter and 193-cm long, was built around the burned-out fourth (Altair) stage of the Scout launch vehicle that remained as part of the orbiting satellite. Explorer 16 carried stainless steel pressurized-cell penetration detectors, impact detectors, capacitor detectors, and cadmium sulfide cell detectors to obtain data on the size, number, distribution, and momentum of dust particles in the near-earth environment. The spacecraft operated satisfactorily during its 7-month life (December 16, 1962, to July 1963), and all mission objectives were accomplished.

Four whip antennas extended from the nose section, and two separate telemetry transmitters, at 136.86 and 136.20 MHz could be turned on for a minute at a time by ground command. At these times it would read out from a data storage unit. A beacon also operated continuously at 136.86 MHz, powered by mercury batteries. Power was supplied by solar cells mounted on the side of the nose section, charging nickel-cadmium batteries.

The payload consisted of six experiments. The first comprised 160 half-cylinder cells, pressurized with nitrogen and made of varying thickness of beryllium-copper. The second had 60 triangular foil gauge detectors mounted under stainless steel skins. The third had 46 copper wire grids wound on melamine cards. The fourth consisted of two cadmium-sulfide cells mounted in aluminized glass flasks. Piezoelectric crystal impact transducers made up the fifth experiment, and the sixth had five groups of p-on-n solar cells with various protective coverings.

Alternate Names

  • Explorer 16
  • 00506
  • 1962 Beta Chi 1
  • S55B

Facts in Brief

Launch Date: 1962-12-16
Launch Vehicle: Scout
Launch Site: Wallops Island, United States
Mass: 100.8 kg

Funding Agency

  • NASA-Office of Aeronautics and Space Technology (United States)


  • Planetary Science

Additional Information

Questions and comments about this spacecraft can be directed to: Dr. David R. Williams



NameRoleOriginal AffiliationE-mail

Selected References

  • Naumann, R. J., The near-earth meteoroid environment, NASA-MSFC, TN D-3717, Huntsville, Ala., Nov. 1966.
  • D'Aiutolo, C. T., et al., Recent NASA meteoroid penetration results from satellities, in NASA, SP-135, Wash., D.C. and Smithsonian Contrib. Astrophys., 11, 239-252, 1967.
  • Hastings, E. C., Jr., Explorer 16 micrometeoroid satellite Description and Preliminary Results for the Period December 16, 1962 Through January 13, 1963, NASA, TM X-810, Wash., D.C., Feb. 1963.
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