27 March 2010, 3:17 pm
Radio waves from Hayabusa arrived from a point in space 27 million kilometers away.
antenna 64 meters in diameter
at Usuda
The waves were received using a parabolic antenna for deep space communication that had a diameter of 64 meters and was located in Usuda-machi, at the foot of the Yatsugatake mountains.
The reception signal was relayed via a terrestrial channel to the satellite operations room at the Sagamihara campus of the Japan Aerospace Exploration Agency (JAXA), located in Sagamihara City, Kanagawa Prefecture. The signal was processed by computer and shown on displays.
The operations room was abuzz with voices.
"Is the orbit system OK?"
"The ion engines are fine. Δv (Delta-v: orbit control variable) is as planned."
"Okay, stop the ion engines! Second stage orbit control has been completed!"
While scrutinizing screens displaying continuously changing data, Kenichi Shirakawa, in charge of attitude control, thought to himself, "Still a little ways to go, can't quite relax yet." Although Hayabusa had indeed successfully gone on an earthbound orbit, the re-entry capsule could not just fall anywhere on Earth. The capsule was to fall in the Woomera Desert in the center of Australia. This would require several fine orbit adjustments.
Hayabusa was equipped with a chemical propulsion thruster for orbit correction, but it was rendered useless as a result of the touchdowns on the Itokawa asteroid. The only way left to adjust the orbit was to use the ion engines, which had not been designed for this purpose. There were still a few things to do, which required even more precision than before.
Shirakawa's job was not over yet.
Kenichi Shirakawa, Expert engineer of 3rd Engineering Department, Space Systems and Public Information Systems Division, NEC Aerospace Systems
