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Radio Frequency Capacitance Probe

NSSDCA ID: 1967-042A-06

Mission Name: Ariel 3
Principal Investigator:Prof. J. Sayers


Electron density determinations were made by measuring the permittivity across a parallel-plate capacitor. The capacitor, composed of two circular grids 7.6 cm in diameter and 5.7 cm apart, was operated at 29 MHz. The electron density could be obtained from the observed permittivity when these grids were at space potential. To ensure that at some time the potential on the grids would be equivalent to the space potential, a linear sweep voltage from -6 V to +6 V was applied to the sensor in 5.2 s. The permittivity at space potential, when the area between the grids was filled with ambient electrons, was measured in terms of the current flowing between the two electrodes. The experiment was operated for 5.2 s and then turned off for the same amount of time while the electron temperature experiment was turned on. There were two outputs, one low speed to a tape recorder and the other high speed real time, available only within range of a telemetry station. Only the maximum values of each sweep were tape recorded while the entire sweep could be read out in real time. The experiment operated normally, and useful data were obtained. A more detailed explanation of the experiment can be found in J. H. Wagner, "University of Birmingham electron density and temperature experiments on the satellite Ariel 3," Radio and Electronic Engineer, v. 35, n. 1, pp. 55-63, January 1968.

Alternate Names

  • Ariel3/RadioFrequencyCapacitanceProbe


  • Space Physics: Ionospheric Studies

Additional Information

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NameRoleOriginal AffiliationE-mail
Prof. J. SayersPrincipal InvestigatorUniversity of Birmingham
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