2006 Volume 22 Issue 1 Pages 1_11-1_20
Hayabusa spacecraft performed a proximity operation including station keeping and hovering around the asteroid (25143) Itokawa from September to November in 2005. In order to navigate and guide the spacecraft to Itokawa, the spacecraft was equipped with sophisticated autonomous navigation and guidance functions including onboard image processing. Since one of three reaction wheels for attitude control failed in late July of 2005 and the second wheel failed in early October, however, the autonomous guidance did not work as designed. To overcome the unexpected anomalies, an optical navigation technique combined with the radiometric information obtained on the ground was used and the proximity operation around the asteroid could be accomplished as planed. This paper presents how those navigation and guidance in proximity phase were carried out, showing with some flight rcsults.
