Fig. 2
From: An in-flight plasma diagnostic package for spacecraft with electric propulsion
The components of the Electric Propulsion Diagnostic Package (EPDP) on the satellite. (a) The erosion sensor is mounted on a radiator close to one of the thruster pairs; (b) The plasma sensor is mounted on the radiator on the opposite side of the satellite next to the other thruster pair; its retarding potential analyzer is oriented toward the plume. Note that both sensors are at comparable positions to the respective thrusters. The instrument control unit of the EPDP is accommodated on the rear side of the same radiator where the plasma sensor is located and therefore not visible in the drawing. The harnesses to the plasma sensor and the erosion sensor are not shown