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VLF Electric Field Detector

NSSDCA ID: 1964-045B-06

Mission Name: P 11-AS
Principal Investigator:Dr. Frederick L. Scarf


The instrumentation for this experiment consisted of a 45.7-cm whip antenna aligned with the spacecraft spin axis and connected to four bandpass channels each with a bandwidth of 15% of the center frequency. The experiment, designed to measure ambient electric fields, had a noise threshold of 400 microvolts per meter. A 1 V/m overcounter to indicate strong emissions was included. The experiment had eight data points per 1.068 min taken in the following sequence: 1.7, 3.9, 7.35, 14.5 kHz, overcounter, 7.35, 3.9, and 1.7 kHz. Each point was separated by 1 s. In real time, transmission occurred over a few specific geographic locations for periods from 5 to 15 min each. The onboard tape recorder periodically allowed sampling of the fields for a complete orbit. During playback of the tape data, malfunctions in the system caused data from all but 16 complete orbits to be degraded. On September 13, 1964, a drift in the voltage-controlled oscillator frequency for the tape-recorded channel limited subsequent tape data obtained to sporadic and noisy recordings. For a more complete description of the experiment see F. L. Scarf et al., "Survey of VLF electric fields in the magnetosphere with the polar orbiting spacecraft, 1964-45A," Radio Science, v. 1, pp. 939-956, August 1966.

Alternate Names

  • P11-AS/VLFElectricFieldDetector


  • 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. Frederick L. ScarfPrincipal InvestigatorTRW Systems Group
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