Hayabusa’s Practice Descent (Rehearsal) on November 4th

Hayabusa currently hovering around a near Earth asteroid Itokawa commenced its descent at 19:17 GMT on November 3rd commanded from the ground, when the altitude to the surface was about 3.5 km. It took an aim at calibrating its proximity laser range finders, visibility calibration and image processing of a target marker as well as deploying a hopping robot MINERVA.

Down to about 700 meters in attitude, both attitude and trajectory control had been performed via Hayabusa’s proprietary autonomous guidance and navigation capability as planned. However, the onboard navigation computer detected anomalous information that did not satisfy the requirement, the abort command was transmitted from the ground at 03:30 GMT on November 4th. The subsequent events were all canceled and the spacecraft fired its chemical engines and started ascent.

When the operation ended from JAXA’s Usuda station, the radio communication to the spacecraft, the attitude control were all in order and the instruments aboard were all functioning normally. Despite the interruption, the project team thinks that it obtained very important information through this practice descent flight, and that this practice does make the strategy stiffer.

The project intends to perform another practice descent again. As of today, the rehearsal schedule together with those for two touching-down and sampling have not been decided yet. What caused the interruption and how it is coped with are presently under investigation and the details will be released after it has been identified.