Hayabusa – Its Technology and Science Accomplishment Summary and Hayabusa-2
- Paper number
IAC-06-A3.5.02
- Author
Dr. Junichiro Kawaguchi, Japan Aerospace Exploration Agency (JAXA)/ISAS, Japan
- Coauthor
Prof. Kuninori Uesugi, Japan Aerospace Exploration Agency (JAXA), Japan
- Coauthor
Prof. Akira Fujiwara, Japan Aerospace Exploration Agency (JAXA)/ISAS, Japan
- Year
2006
- Abstract
Hayabusa (MUSES-C) spacecraft successfully performed the touching down to the surface and attempted to collect sample of the asteroid Itokawa in November of 2005. Hayabusa, a highly sophisticated robotic spacecraft, conducted three practice descents and two touching down events including a landing. The orbit control that targets a very narrow smooth area on Itokawa, whose width is a few tens meters was accomplished by a new navigation strategy. With two reaction wheels lost, the spacecraft inevitably relied on the jets (reaction control system), which put some translation disturbance to the descent trajectory and it made the guidance accuracy significantly degraded. The requested guidance accuracy is less than 1 centimeter per second, which however affects the landing dispersion of several tens meters during one hour descent flight. The radio communication takes about forty minutes for a round trip and a remote control had to be given up and the final descent was made completely autonomously. What was taken is a Real-time Land Mark Tracking to navigate and localize the spacecraft position every fifteen minutes. This strategy was conceived possible in off-line. However, the use of it in real time was never assumed since the conventional processing takes a lot of time to conclude the localization. But the Hayabusa team devised a sophisticated method to have a navigation result almost within several minutes and it did contribute to acquiring the precise position information with respect to the Itokawa coordinate. In addition, the autonomous landing sequence included the video-assisted horizontal velocity cancellation via a Target Marker Tracking method, which was also developed for the purpose. Attitude alignment to the surface was performed by the Laser range Finder aboard successfully as well. At the first touching down event (November 20th), the spacecraft touched down to the surface twice and landed for about thirty minutes long. And it lifted off owing to the emergency command issued from the ground. Hayabusa spacecraft is the first spacecraft that lifted off again from a celestial object other than the moon. At the second touching down event (November 26th), the sequence was configured never to lift off without detecting of sampler horn deformation and without issuing projectile shot command. The sequence actually functioned successfully as programmed. During the proximity operation phase around Itokawa, Hayabusa gathered a lot of measurements by Visible Imager (AMICA), Laser Altimeter (LIDAR), Near Infrared Spectrometer (NIRS) and X-ray Fluorescent Spectrometer (XRS). The highest resolution of the images taken is surprisingly small to about 6 mm, and the finest structure of the surface was actually glimpsed and the detailed information was obtained. The surface mapping was completed with the surface conditions and mineralogical information scanned almost perfectly. Itokawa is the first object that is not covered with regolith and was exposed to the human beings. The presentation presents the details of the engineering and scientific results during the proximity phase. Hayabusa unfortunately suffered from a fuel leak problem and currently undergoes the rehabilitation so that the return cruise can commence from early 2007 by driving its ion engines. The expected return of the spacecraft is scheduled in June of 2010. JAXA considers to launch Hayabusa-2 in near future taking the heritages used in Hayabusa. JAXA started the investigation.
- Abstract document
- Manuscript document
IAC-06-A3.5.02.pdf (🔒 authorized access only).
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