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DC Fields by Double Probe

NSSDCA ID: 1977-029A-07

Mission Name: ESA-GEOS 1
Principal Investigator:Dr. Arne Pedersen


This instrument (part of ESA Exp. S-300) consisted of two vitreous carbon spheres mounted at the tips of the 20-m cable booms, which extended radially from the spacecraft perpendicular to the spin axis. This investigation was concerned with the dc single-axis electric field analysis. The two output signals were evaluated in terms of dc electric field and conditioned for further treatment in the analysis of ac electric fields. The output from one sphere was signal-conditioned on a linear scale whereas the differential output from the two spheres was compressed logarithmically. In addition, the two outputs were passed through 450 Hz to 77 kHz filters. These filtered signals were differenced and all three signals were made available for analysis by the sweep-frequency analyzers and digital correlator as part of the 77-029A-05 (Petit), 77-O29A-10 (Ungstrup), and 77-029A-01 (Beghin) investigations. The sensitivity of this probe was about 1.0E-4 V/m at dc and 1.0E-8 volts per meter per square root of hertz for ac.

Alternate Names

  • ESA-GEOS1/DCFieldsbyDoubleProbe
  • S300
  • S328

Funding Agency

  • European Space Agency (International)


  • 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. Karl KnottOther InvestigatorESA-European Space Research and Technology Centre
Dr. Rejean J. L. GrardOther InvestigatorESA-European Space Research and Technology
Dr. Dyfrig JonesOther InvestigatorBritish Antarctic Survey
Dr. Arne PedersenPrincipal InvestigatorESA-European Space Research and Technology
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