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Plasma Probe

NSSDCA ID: 1967-070A-06

Mission Name: Explorer 35
Principal Investigator:Prof. Herbert S. Bridge


A multigrid, split-collector Faraday cup mounted on the equator of the spacecraft was used to study the directional intensity of solar wind positive ions and electrons with particular emphasis on the interaction of the solar wind with the moon. Twenty-seven integral current samples (requiring about 4.3 s) were taken in an energy-per-charge window from 80 to 2850 eV. Then the current was sampled in eight differential energy-per-charge windows between 50 and 5400 eV at the azimuth where the peak current appeared in the previous series of integral measurements. These measurements (integral and differential) took about 25 s. Both the sum and difference of collector currents were obtained for positive ions. Only the sum was obtained for electrons. A complete set of measurements (two collector plate sums and one difference for protons, and one collector plate sum for electrons) required 328 s. The experiment worked well from launch until its failure in July 1968. For further details, see Lyon et al., J. Geophys. Res., v. 72, p. 6113, 1967.

Alternate Names

  • Explorer35/PlasmaProbe
  • Plasma Probe-Faraday Cup(Protons, Electrons .05-5.4KeV)


  • Space Physics: Magnetospheric Studies
  • Space Physics: Heliospheric Studies

Additional Information

Questions and comments about this experiment can be directed to: Coordinated Request and User Support Office



NameRoleOriginal AffiliationE-mail
Prof. Herbert S. BridgePrincipal InvestigatorMassachusetts Institute of Technology
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