Hayabusa Hovers Near Asteroid Itokawa

Hayabusa arrived Itokawa on 10:00 am, 12 Sep (JST: Japanese Standard Time). Now Hayabusa hovers around 20 kilometers away from asteroid Itokawa.

This picture was taken at 8:35 am, 12 Sep (JST) just before the settlement by the visible imager AMICA. Field of view is two degrees. The photo shows contrast of rocky and hilly region and smooth area, which may suggest the origin of this asteroid. This feature may be a key to consider Itokawa’s origin and evolution. The scientific observation will be conducted for about two months including sampling and topographic measurement.

Color composite image will be available soon.

The figure below shows the Doppler velocity difference between Itokawa and Hayabusa. The velocity dropped down to zero around 01:17 UTC. It indicates that Hayabusa fired its chemical propulsion thruster so that the relative velocity was canceled. Vertically approaching speed is taken in km/sec and is shown the doubled speed corresponding to a round trip measurement. Horizontally is shown the Universal Time (World Time: UTC) when the Doppler information was collected. Since radio travels for about 17 minutes from Hayabusa, the last firing occurred around 01:17 UTC. The resulted relative velocity was confirmed down to about 0.25 mm/sec.