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Ion Velecity Instrument(IVI) Planar Reta rding Potential Analyzer/Drife Meter(DNS)

NSSDCA ID: 1988-026A-03

Mission Name: San Marco-D/L
Principal Investigator:Prof. William B. Hanson


This investigation uses a planar retarding potential analyzer, designed to obtain measurements of relative thermal-ion velocity, plasma density, and ion temperature. The ion angle of arrival can be determined by use of a square aperture collimator and a split collector. Together with knowledge of spacecraft motion, this allows computation of the three-dimensional thermal-ion motion along the orbital path. Plasma density and temperature are calculated by interpretation of the volt-ampere profile produced by the instrument for a given impressed voltage pattern on the grids and collector. Ion velocity measurements are obtained once each spacecraft spin period (10 s).

Alternate Names

  • IVI
  • SanMarco-DL/IVI

Funding Agency

  • NASA-Office of Space Science (United States)


  • Space Physics: Ionospheric Studies

Additional Information

Questions and comments about this experiment can be directed to: Dr. Dieter K. Bilitza



NameRoleOriginal AffiliationE-mail
Prof. William B. HansonPrincipal InvestigatorUniversity of Texas, Dallas
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