138 Propulsion Units Launched in 4 Years: A Review and Lessons Learned

After the first launch of an ENPULSION NANO thruster in 2019 together with FOTEC1,2,3, which verified for the first time the operation of a propulsion system based on liquid metal Field Emission Electric Propulsion (FEEP) in space, ENPULSION has delivered hundreds of flight systems to 36 different commercial customers. To date, 135 additional ENPULSION NANO systems have been launched on a variety of spacecraft across different platforms and customers. In addition, the ENPULSION MICRO R3 , an increased power and thrust unit, has been developed, which was successfully demonstrated in orbit in 2021. Recently, the first new generation ENPULSION NANO AR3 propulsion system was launched to debut on orbit. To date, hundreds of flight models have been manufactured, acceptance tested and delivered to customers. Based on lessons learnt during manufacturing, AIT and in-space operation of the ENPULSION NANO, a new generation of propulsion systems with increased resilience has been developed, denoted R3 . In this paper we provide an overview of the onorbit statistics of the ENPULSION propulsion systems. This includes the evolution of launch history of the ENPULSION NANO over time, the accumulated orbit life for all operational propulsion systems that ENPULSION has visibility on confirmed thrust generation, as well as the accumulated orbit life for operational thrusters between launch and last telemetry of thrust maneuver made available to ENPULSION. We then present efforts undertaken in AIT, onorbit operation support and ground testing campaigns conducted in different independent facilities. Based on this, we derive lessons learnt, best practices and limitation over a large number of customers of the smallsat community, over different systems and different implementations for a standardized electric propulsion system based on the ENPULSION NANO