RF Helicon-based Inductive Plasma Thruster (IPT) Design for an Atmosphere-Breathing Electric Propulsion System (ABEP)

Challenging space missions include those at very low altitudes, where the atmosphere is source of aerodynamicdrag on the spacecraft. To extend such missions lifetime, an efficient propulsion system is required. Onesolution is Atmosphere-Breathing Electric Propulsion (ABEP). It collects atmospheric particles to be usedas propellant for an electric thruster. The system would minimize the requirement of limited propellantavailability and can also be applied to any planet with atmosphere, enabling new mission at low altituderanges for longer times. Challenging is also the presence of reactive chemical species, such as atomic oxygenin Earth orbit. Such species cause erosion of (not only) propulsion system components, i.e. acceleration grids,electrodes, and discharge channels of conventional EP systems. IRS is developing within the DISCOVERERproject, an intake and a thruster for an ABEP system. The paper describes the design and implementationof the RF helicon-based inductive plasma thruster (IPT). This paper deals in particular with the design andimplementation of a novel antenna called the birdcage antenna, a device well known in magnetic resonanceimaging (MRI), and also lately employed for helicon-wave based plasma sources in fusion research. This isaided by the numerical tool XFdtd®. The IPT is based on RF electrodeless operation aided by an externallyapplied static magnetic field. The IPT is composed by an antenna, a discharge channel, a movable injector,and a solenoid. By changing the operational parameters along with the novel antenna design, the aim is tominimize losses in the RF circuit, and accelerate a quasi-neutral plasma plume. This is also to be aided by theformation of helicon waves within the plasma that are to improve the overall efficiency and achieve higherexhaust velocities. Finally, the designed IPT with a particular focus on the birdcage antenna design procedureis presentedThis project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No. 737183Peer ReviewedPostprint (author's final draft