TANDEM: a High Power, Magnetically Shielded Hall Thruster with a Nested Configuration

High thrust, high specific impulse electric propulsion systems have seen an increased effort in their development during the past decades at ESA and European space companies. The need of future all-electric human and robotic transportation missions has driven the progress toward high power (>20 kW) Hall thruster propulsion systems. In this optic, a 25 kW dual-channel Hall thruster is under development at the University of Pisa in joint collaboration with Aerospazio Tecnologie, in the framework of the ESA TDE program. The thruster has two coaxial channels with a magnetically shielded topology and a central hollow cathode. The nested configuration allows the thruster to effectively operate in a wide range of power, with both xenon and krypton as propellant, by activating each single channel alone or both the channels, at different level of voltage and current. To this regard, the cathode has been specifically designed to operate in a wide range of current with both the propellants. The thruster channels has been sized by extensively using the scaling tools developed by UniPi The same tools have allow to set the performance envelope of the thruster, used to establish the requirements of the experimental equipment and the issue of a test plan. Details of the thruster design and its current status are presented in this paper.