Cylindrical electrostatic probes employed on Alouette II and explorer XXXI satellites

The cylindrical electrostatic probes flown on both AIouette II and Explorer XXXl enable intersatellite comparisons of directly measured parameters to be made. The sensors are identical, but differences between the two satellites resulted in differences of data format and probe potential. Interference from the topside sounder on Alouette II has made data processing difficult.