OGO-V Ion Spectrometer

The ion spectrometer aboard OGO-V is a most versatile instrument for topside ionospheric and magnetospheric investigations. The concentration profiles of O+, He+ and H+ ions are obtained in the topside ionosphere with excellent spatial resolution and with a sensitivity sufficient to measure less than 1 ion/cm3. The dynamic range of the instrument is better than 8 orders of magnitude. These functions are accomplished with an absolute minimum of telemetry bandwidth. The instrument also functions as an energetic particle analyzer and is capable of measuring energy distributions of protons from 0 to 600 eV. The bow shock crossings of the OGO-V vehicle are easily detected with the ion spectrometer and temperature measurements within the magnetosheath are obtained.