Hayabusa Closes In on Asteroid Itokawa
But before that can happen, the spacecraft must complete a detailed reconnaissance of Itokawa. After its arrival on September 12th, Hayabusa (Japanese for "falcon") maintained a 20-km standoff distance. The new, closer vantage point, reached on September 30th, will allow mission scientists to create a high-definition model of Itokawa's shape using images and laser altimetry. They'll also study results from two infrared spectrometers to identify target areas with interesting compositions.
Generally the mission has been going well, according to a status report released by the Japan Aerospace Exploration Agency (JAXA). Hayabusa's automated navigation system has kept the craft hovering over the asteroid's sunlit half and has controlled the pointing of its camera and other intruments. As of October 4th the detailed mapping of Itokawa was nearly complete.
But concern has mounted since the loss on October 2nd of an attitude-stabilizing "control wheel." Another wheel malfunctioned back on July 31st, leaving just one such unit plus two thruster rockets to maintain the spacecraft's orientation. Engineers are studying how to reduce the thrusters' fuel consumption so that the sampling can occur as planned.
In December the spacecraft will use its ion-propulsion engine to begin the return trip to Earth, and a canister bearing two tiny samples should be in scientists' waiting hands by June 2007. Hayabusa also carries a small hopping lander, called Minerva, that will photograph the surface from several locations.