This experiment was designed to provide information on the intensity, angular distribution,
energy spectrum, and net flows along field lines, of electrons in the thermosphere with energies between
1 and 500 eV. The instrument consisted of two identical oppositely directed hemispherical electrostatic
analyzers, and it had 30 operating modes. Each spectrometer had a relative energy resolution plus or
minus 2.5% and a geometric factor on the order of 0.001 sq cm sr, independent of electron energy.
Three separate energy ranges could be sensed: 0 to 25, 0 to 100, or 0 to 500 eV. Measurements from
these intervals could be sequenced in 5 different ways. Data could be taken from either sensor
separately, or alternately with time resolution varying from 0.25 to 8 s. There were two deflection
voltage scan rates determined by spacecraft clock. This voltage was changed in 64 steps, and was done
at 4 or 16 steps per telemetry frame. With 16 frames/s, this allowed a choice of either one 64-point
spectrum, or four 16-point spectra in 1 s. The longest (8 s) cycle of data involved observations using
increasing voltage steps for the lowest, middle, lowest, then highest energy ranges (in that order)
for 1 s each. A repeat for decreasing voltage steps completed the cycle. A more detailed description
of this experiment may be found in J. P. Doering et al., Radio Sci., v. 8, n. 4, p. 387, 1973.
NSSDC has all the useful data that exist from this investigation.