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Rubidium Vapor Magnetometer

NSSDCA ID: 1961-032A-02

Mission Name: Ranger 2
Principal Investigator:Dr. James P. Heppner


A rubidium-vapor magnetometer, mounted in the center of a hollow spherical fiberglass shell 13 in. in diameter, was designed to measure the magnitude and direction of the magnetic field in interplanetary space and to detect occurances of temporal and spatial fluctuations. Bias coils were wound around the shell to send electric currents of known strengths during the measuring sequence. Proper sequencing of currents in the coils allows determination of both the strength and direction of the magnetic field in space. The instrument took measurements of fast field fluctuations of up to 30 gammas per sec in order to study the fine structure of the field. The sensitivity range of the experiment was from 0.05 to 105 gammas, with an accuracy of .05 gamma.

The measurements were to be made of the geomagnetic field from a distance of approximately 6 Earth radii, but Ranger 2 did not leave Earth orbit. Due to the low orbit, the spacecraft never got far enough away from Earth for the field strength to be less than 105 gammas, which was outside the range of the instrument, and no flight data were obtained.

Alternate Names

  • Ranger2/RubidiumVaporMagnetometer


  • Space Physics: Heliospheric Studies

Additional Information

Questions and comments about this experiment can be directed to: Dr. David R. Williams



NameRoleOriginal AffiliationE-mail
Dr. James P. HeppnerPrincipal InvestigatorNASA Goddard Space Flight Center
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