Solid Diamond Insulators for Hall Thrusters

Concern exists in the space industry about the effect of µPPT and the Hall Effect Thrusters on spacecraft and their power generation systems. Numerical modeling data must be verified with on-orbit data because ground measurements of contamination effects in vacuum chambers do not fully reflect space conditions. Thus, a sensor package will be manifested aboard an upcoming spacecraft flight for the purpose of developing a predictive capability for how electric propulsion thrusters interact with typical spacecraft. This sensor package will consist of the Propulsion Instrumentation Electronics Package (PIE), which will be used to set, control and sample 30 different sensors. The PIE is smaller, lighter, and more robust than typical central processing units; it uses field programmable gate arrays to store and pass commands, set biases, and collect data from the sensors before forwarding it to the spacecraft bus. Plume environment characterization sensors will include one ion spectrometer that will measure mass and energy distributions of ions (primarily Xe+ and Xe++) emitted from the thruster, and two electron probes that will measure electron density and temperature of the plasma environment. Surface contamination characterization sensors will include two solar cell sensors, which will measure specific environmental effects on the solar arrays by characterizing changes to the current vs. voltage response curve of the solar cell over time, ten photometer sensors, which will measure the contamination and erosive effects of electric propulsion thrusters on the optical properties of materials, and ten radiometer sensors that will measure contamination and the erosive affects to the thermal absorption and emissive properties of spacecraft surface materials. Testing and verification of PIE functionality was accomplished with hardware and software that simulated spacecraft sensors in laboratory conditions.