Challenges Using Rarefied Atmospheric Gases as Propellant for an RAM-EP System

Abstract Many challenges have to be faced in order to develop an air-breathing electric propulsion system using a radio frequency ion thruster (RIT). The underlying assumptions of gas-surface-interactions for DSMC simulations of the intake give a wide spread of results in operating points available for the thruster. Thus, it is necessary to replicate the VLEO conditions experimentally in the future. Furthermore, precise experimental characterization of the propulsion system using atmospheric propellants is essential for mission success, although this also presents significant challenges. The background pressure of the test facility can cause an overestimation of the measured atomic-to-molecular ratio by a factor of 10. The sputtering of the beam dump can cause a back-streaming of carbon particles to the thruster of approx. $$3.4 \times 10^{13}$$ 3.4 × 10 13 particles/(s mA). Moreover, the reactive propellant causes significant material degradation of all materials in direct contact with the plasma.