Design and tests of a superconducting magnet system for demonstration operation in orbit

Applied-field magnetoplasmadynamic (AF-MPD) thrusters have been proposed as highly propellant-efficient thrusters for satellites and spacecraft. The electromagnets for these devices have only been reducible to practical dimensions with the maturation of high-temperature superconductors. We report the development and ground testing of such a magnet which has been designed and constructed with the intention of deploying to the International Space Station and testing in orbit. The magnet is of dimensions suitable for accommodating a small thruster, will be cooled by a miniature space-compatible cryocooler and energised by a flux pump. It can generate a magnetic field of up to 760 mT operating at around 77 K in that configuration. A passive magnetic shield has been incorporated in order to comply with stray-field requirements of the ISS when operating at the target operational field of 300 mT.