Current progress in the development of an ECR plasma source for atmosphere-breathing electric propulsion system

Abstract This contribution reports on the experimental demonstration of plasma ignition in an electron-cyclotron-resonance atmosphere-breathing electric propulsion source at pressures representative of very low Earth orbit. Using a MHz-range birdcage resonator in combination with a tailored magnetic field, we achieved sustained plasma discharge at pressures consistent with conditions expected after intake compression at altitudes near 200 km. The scalability of the birdcage resonator with increasing forward power is explored, revealing the potential for future improvement regarding power scaling of the thruster. These findings identify both the feasibility of electrodeless ignition at VLEO pressures, and the engineering limits imposed by resonator heating. We further discuss quantitative links between measured ion currents, estimated thrust, and extraction efficiency. Our results establish critical design insights for scaling ABEP technology toward flight-ready operation.