Description: The proposed work investigates an approach that would allow an annular ion engine geometry to achieve ion beam currents approaching the Child-Langmuir limit. In this respect, the annular engine, whose design inherently allows for significant increases in perveance by resolving the span-to-gap problem, can achieve the projected high current densities necessary for high thrust, high power applications. The case for high power gridded ion thrusters is compelling if not only for risk reduction in contrast to lower TRL Hall thruster variants such as the nested channel systems. This point cannot be over emphasized as there is now significant effort and resources applied to Hall engine development. Yet there still remains some uncertainty as to how high power variants or magnetically insulated variants will actually perform in space. Interpretation of high power Hall engine operation in ground test facilities is also not completely well understood. This is in contrast with gridded ion technology whose facility corrections are well understood. The current investment in high power gridded ion thruster technology is minimal. This effort seeks to address this gap in technology development and in the process continue the advancement of a credible risk reducing technology for high power mission applications.

Benefits: The technology under development here has numerous applications in the area of electric propulsion, supporting those current and future NASA missions with high power requirements.

This technology is also enabling for DOD customers as well as commercial satellite interests for orbital transfer applications. The appeal of the system to non-NASA customers has been heightened through the availability of high power solar arrays. The coupling of such arrays with high power, efficient gridded ion is indeed mission enabling. In this respect, there would be likely benefits for both government satellites as well as commercial satellite markets. Because the ion source design paves the wave for very high beam currents, applications in materials processing and neutral beam injectors (fusion) are anticipated.