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

The SUPREME (Superconductor-Based Readiness Enhanced Magnetoplasmadynamic Electric Propulsion) thruster, in development by Neutron Star Systems DE GmbH (NSS) in collaboration with the Institute of Space Systems (IRS), University of Stuttgart, is 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. Both magnetic coil for the applied field and thruster anode are made of copper and are water-cooled. SUPREME will have a radiation cooled anode and a high temperature superconducting coil aiming at nominal maximal magnetic fields of 1.2 T. 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, and potential mission scenarios are investigated.