Application of solar electric propulsion to a comet surface sample return mission

Current NASA solar electric propulsion technology application readiness and NASA's evolutionary xenon thruster-based propulsion systems are compared for a comet surface sample return mission to Tempel 1. Mission and systems analyses are conducted over a range of array power for each propulsion system and for two medium-class launch vehicles. Engine configurations investigated for NASA, solar electric propulsion technology application readiness included five operational engines with one spare and six operational engines with on I e spare. The NASA evolutionary xenon thruster configuration investigated included two operational engines plus one spare, with performance estimated for two different throttling modes. Figures of merit for this comparison include solar electric propulsion dry mass, average engine throughput, and net nonpropulsion payload returned to Earth. For the comet surface sample return mission, the NASA evolutionary xenon thruster system outperforms the NASA solar electric propulsion technology application readiness system with the advantage of lighter dry mass and simpler hardware implementation.