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Spherical Ion and Electron Trap

NSSDCA ID: 1964-054A-03

Mission Name: OGO 1
Principal Investigator:Dr. Rita C. Sagalyn


The objective of this experiment was to measure the flux, temperature, and energy distribution of electrons and positive ions having energies ranging from thermal up to 1000 eV, as a function of position (altitude, L shell, etc.) and of time (due to solar and magnetic activity). Two spherical electrostatic sensors, used as omnidirectional plasma probes, were mounted on a short boom. One sensor was designed for electron measurements and consisted of two concentric spheres. The outer sphere was a grid that allowed the ambient electrons to pass through and be collected by the inner sphere. The second sensor, which was designed to measure positive ions, consisted of three concentric spheres, an outer aperture grid, an inner collecting sphere, and a suppressor grid between them. Collector currents were measured with electrometers. Logic circuits controlled the sequence of the measurement operations, so that different potentials were applied between the spheres in prescribed patterns. A complete measurement cycle took 25.6 min. Essentially, the experiment was designed to cycle in three major modes of operation to provide data on the flux of charged particles, the mean particle temperatures, and the energy distributions of the plasma particles. The output currents from each sensor were calibrated once per experiment cycle. More details can be obtained from Sagalyn, R. C., and M. Smiddy, "Results of charged particle measurements in the energy range 0 to 1000 electron volts, OGO-A," Space Research 6, 1966. Data from this investigation no longer exist.

Alternate Names

  • OGO1/SphericalIonandElectronTrap


  • 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. Michael SmiddyOther InvestigatorPhillips Laboratory (nee USAF Geophysics Lab, nee Cambridge Labs)
Dr. Rita C. SagalynPrincipal InvestigatorPhillips Laboratory (nee USAF Geophysics Lab, nee Cambridge Labs)
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