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Planar Ion and Electron Trap

NSSDCA ID: 1964-054A-04

Mission Name: OGO 1
Principal Investigator:Dr. Elden C. Whipple


This experiment was flown to measure densities and energy distributions of thermal ions and electrons over the altitude range from below the F-maximum region of the ionosphere to several earth radii. In addition, the experiment yielded some data concerning ion masses, fluxes and directions of quasi-energetic particles, and the polarity and magnitude of the vehicle potential. The sensor was an electron and ion trap that consisted of four parallel circular plane grids in front of a collecting plate. The current to the collector was measured by a vibrating reed electrometer with an automatic range change for each decade of current from 1.0E-13 to 1.0E-6 A. The four modes of experiment operation used were a low-resolution and a high-resolution mode for both ions and electrons. In each mode, a variable potential was applied to one grid in the trap, while the potentials on each of the other grids and the collector were held constant. The average time to complete a mode was between 12 and 15 s, and the complete cycle of four modes averaged less than 1 min. The measured current and applied varied voltage were digitized and stored in the experiment shift register until read out to the spacecraft telemetry system. Further details regarding experiment design and operation can be found in "A satellite ion-electron collector, experimental effects of grid transparency, photoemission, and secondary emission," by E. C. Whipple, J. W. Hirman, and R. Ross, ESSA Tech. Report. ERL 99-AL1, December 1968 (TRF B02033). Data sets no longer exist from this investigation.

Alternate Names

  • OGO1/PlanarIonandElectronTrap


  • Space Physics: Ionospheric Studies
  • Space Physics: Magnetospheric Studies

Additional Information

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



NameRoleOriginal AffiliationE-mail
Dr. Ballard E. Troy, Jr.Other InvestigatorUS Naval Research Laboratory
Dr. Elden C. WhipplePrincipal InvestigatorUniversity of California, San
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