Plasma diagnostics and numerical modeling of a microwave ion engine

The Institute of Space and Astronautical Science is p lanning an asteroid sample return mission named MUSES-C, for which a microwave ion engine system is used as primary propulsion. This paper describes the design of a 7-mN/300W class microwave discharge ion e n g i n e , fo l lowed by an e v a l u a t i o n of p lasma characteristics inside the microwave discharge chamber using a Langmuir probe. The maximum, plasma density inside the discharge chamber was an order of the cut off density of the 4.2 GHz microwave, and a ring-shaped localized plasma distribution was observed in the case of efficient plasma production.