Characterizing Electrode Passivation in Air Breathing Electric Propulsion

Over time, the electrodes in air-breathing electric propulsion (ABEP) systems deteriorate and become less effective in generating thrust. This degradation is caused by the interaction between the electrodes and the surrounding air, leading to the formation of thin layers consisting of nitrides and oxides on the electrode surface. These thin layers alter the properties of the electrodes, such as how they emit light, and consequently reduce the efficiency of thrust generation. To better understand and analyze this process of electrode deterioration in ABEP systems, we carry out a series of experiments. These experiments involve real-time monitoring of the growth and roughness of the thin layers on the electrodes. We employ micro-Raman spectroscopy and optical emission spectroscopy techniques to identify the chemical composition of these thin layers. Additionally, we use scanning electron microscopy to examine the surface characteristics of the passivated electrodes and gather relevant data. Finally, we assess the performance of a pulsed plasma thruster by evaluating its thrust efficiency and discharge characteristics as the thin layers develop. This investigation provides valuable insights into the impact of these thin layers on the overall functionality of the propulsion system.