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Low-Energy Proton and Electron Differential Energy Analyzer (LEPEDEA)

NSSDCA ID: 1966-049A-08

Mission Name: OGO 3
Principal Investigator:Prof. Louis A. Frank


This experiment was designed to measure the differential energy spectra of protons and electrons over the energy range 50 eV to 49 keV (subdivided into 15 energy intervals) within and in the vicinity of the earth's magnetosphere. The instrumentation consisted of two cylindrical electrostatic analyzers (Low Energy Proton and Electron Differential Energy Analyzers or LEPEDEAs) and two Bendix continuous channel multipliers (channeltrons). The accumulation time per channel was about 1 s. Approximately 5 min were required to complete a scan of the entire energy range. After the spacecraft attitude control system failed on July 23, 1966, one of the LEPEDEAs was oriented parallel to the spacecraft spin axis, and the other was oriented perpendicular to the spin axis. (The spin period varied from about 91 to 122 s.) More details regarding experiment design may be found in Frank, L. A., "Low-energy proton and electron experiment for the Orbiting Geophysical Observatories B and E," Dept. of Physics and Astronomy, State Univ. of Iowa, Iowa City, Iowa, July 1965 (TRF B00609).

Alternate Names


Funding Agency

  • NASA-Office of Space Science (United States)


  • 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
Mr. H. KielGeneral ContactUniversity of Iowa
Prof. James A. Van AllenOther InvestigatorUniversity of Iowa
Prof. Louis A. FrankPrincipal InvestigatorUniversity of
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