Overview of recent activities and research interest in electric propulsion in the US

In recent years, with the rise of large satellite constellations, electric propulsion has increasingly become a standard technology in space missions. This trend has been driven primarily by the adoption of low-power, inert gas-fed Hall thrusters, followed by gridded ion engines and resistojets, particularly on small to medium satellite platforms (<500 kg). Despite this progress, several fundamental physical phenomena related to ion acceleration remain poorly understood and warrant further investigation.

Moreover, current space-qualified electric propulsion technologies have yet to be fully optimized for the diverse requirements of emerging mission profiles. Recently, the electric propulsion community has explored a wide range of thruster concepts and configurations aimed at enhancing performance and operational flexibility. In particular, the United States has led numerous initiatives, including the use of alternative propellants (e.g., water, nitrogen), improved thruster–PPU integration, studies on facility effects (electrical and pressure-related), and the development of high power density thruster systems.

This presentation will provide a concise overview of selected published efforts in these areas and highlight key findings and implications for future research and development.