2006 Volume 22 Issue 1 Pages 1_1-1_10
The microwave discharge ion engine “μ10” has a long life and high reliability because of electrodeless plasma generation in both the ion generator and the neutralizer. A single μ10 generates a thrust of 8 mN, specific impulse of 3,200 seconds, and consuming 350 W of electric power. Four μ10s propelled the “Hayabusa” asteroid explorer, launched on May 2003, combining a new orbit change scheme “Delta-V Earth Gravity Assist”. In 2005, Hayabusa, using solar electric propulsion, managed to successfully cover the distance between 0.86 AU and 1.7 AU from Sun in the solar system, as well as rendezvous with, land on, and lift off from the asteroid Itokawa. During the 2-year flight, the ion engine system generated a delta-V of 1,400 m/s while consuming 22 kg of xenon propellant and operating for 25,800 hours. Hayabusa solved failures of reaction wheels and chemical thrusters by means of xenon cold gas jet from the ion engine system and aims to return to Earth in 2010.
