Microwave Discharge Ion Engines Onboard Hayabusa Asteroid Explorer

Abstract

The cathode-less electron cyclotron resonance ion engines propelled the Hayabusa asteroid explorer, launched in May 2003, which is focused on demonstrating the technology necessary for a sample return from an asteroid, using electric propulsion, optical navigation, material sampling in a zero gravity field, and direct re-entry from a heliocentric orbit. It rendezvoused with the asteroid Itokawa after a two-year deep space flight using the ion engines in 2005 and accomplished a round trip space mission between Earth and an asteroid in 2010. For the deep space odyssey between Earth and the asteroid, the ion engines served the total accumulated operational time 39637 hour･unit, the powered spaceflight in 25590 hours. Hayabusa and microwave discharge ion engines pioneered the space exploration and will bring us further deep space. This paper also report recent topics in space technology associated with the surface science.