NASA Logo, National Aeronautics and Space Administration
NASA Space Science Data Coordinated Archive Header

Passive Ionospheric Monitor (SSI/P)

NSSDCA ID: 1977-044A-04

Mission Name: DMSP 5D-1/F02
Principal Investigator:Lcol A. Lee Snyder


The instrument consisted of a high-frequency radio receiver connected to a short antenna that swept from 1.3 to 13.9 MHz in 100-kHz steps. The device was used to monitor the ionospheric breakthrough frequency of noise generated by manmade or natural sources below the f2 layer to obtain the critical frequency of this layer (fof2). The fof2 parameter was used in constructing electron-density profiles used in forecasting the state of the ionosphere. The instrument could detect electric fields down to 10 microvolts/m.

Alternate Names

  • DMSP5D-1-F02/SSI/P
  • Passive Ionospheric Monitor
  • SSI/P


  • Space Physics: Ionospheric Studies

Additional Information

Questions and comments about this experiment can be directed to: Coordinated Request and User Support Office



NameRoleOriginal AffiliationE-mail
Lcol A. Lee SnyderPrincipal InvestigatorPhillips Laboratory (nee USAF Geophysics Lab, nee Cambridge Labs)
[] NASA Logo -