Downscaling the 100 kW SX-3 AF-MPD to the 5 kW SUPREME thruster

Abstract The SUPREME (Superconductor-Based Readiness Enhanced Magnetoplasmadynamic Electric Propulsion) thruster, where the scaling approach shown here is performed by Neutron Star Systems in collaboration with the Institute of Space Systems (IRS), University of Stuttgart, is an applied field magnetoplasmadynamic thruster designed for a nominal power level of 5 kW to have a wide range of commercial applications. Basis for the design is the SX3 thruster, developed at IRS, which is an engineering model operated between 2 and 100 kW with magnetic fields up to 400 mT. For flight applications, copper coils, as used for the SX3, are limited in achievable magnetic field strength and suffer from high thermal losses. High temperature superconducting coils provide a path to flight technology, minimizing these losses and providing high magnetic field strengths like the 1.2 T intended for SUPREME, which will also have radiation cooled electrodes. This work describes a design approach in the absence of a numerical simulation code for the plasma inside the thruster. The downscaling process described here relies on maintaining critical plasma parameters of the SX3 thruster to produce similar thruster performance with the smaller SUPREME. The downscaling to obtain a discharge unit geometry and the design process for the superconducting coil are described in detail, the SUPREME performance is estimated with a scaling code developed at IRS. Lastly, potential mission scenarios within the Earth’s gravitational field and interplanetary missions to Mars and Ceres are investigated to assess potential applications for SUPREME.