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Positive Ion Composition

NSSDCA ID: 1964-054A-06

Mission Name: OGO 1
Principal Investigator:Mr. Harry A. Taylor, Jr.


The instrumentation for this experiment consisted of two ceramic Bennett radio-frequency mass spectrometers to measure thermal atmospheric positive ions in the range 1 to 45 u. The low-range mass spectrometer measured ions with mass-to-charge ratios (M/Q) from 1 to 6 u, with a resolution of 0.5 u. The high-range mass spectrometer measured ions with M/Q values from 7 to 45 u, with a resolution of 1 in 20 u. Ion concentrations from 5 to 1.0E6 ions per cc could be measured. The time required for a complete scan of the mass range was 64 s, which corresponded to a spatial resolution of about 300 km. The successful operation of the experiment provided the first high-resolution, in situ, direct measurements of the positive ion composition, from an altitude of less than 1000 km to interplanetary space and beyond the boundary of the magnetosphere. The instrumentation is described in Taylor, H. A., et al., "Positive ion composition in the magnetoionosphere obtained from the OGO-A satellite," J. Geophys. Res., v. 70, n. 23, p. 5769, December 1965. Data sets are no longer available from this investigation.

Alternate Names

  • Atmospheric Mass Spectrometer
  • OGO1/PositiveIonComposition

Funding Agency

  • National Aeronautics and Space Administration (United States)


  • Space Physics: Ionospheric Studies
  • 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. Nelson W. SpencerOther InvestigatorNASA Goddard Space Flight Center
Mr. Harry A. Taylor, Jr.Principal InvestigatorNASA Goddard Space Flight Center
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