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MINERVA Fails To Touchdown On Itokawa
Sydney, Australia (SPX) Nov 15, 2005 On the weekend the Japan Aerospace Exploration Agency's Hayabusa conducted its second test descent to the asteroid Itokawa, to prepare for a landing and collection of samples, announcing that it "performed the touch down test with success," but that success was shortlived. The spacecraft first attempted this descent test on November 4 (The team has not yet figured out exactly why the spacecraft aborted at the time it did, but they have an idea it's got something to do with the navigation camera. Hayabusa's navigation, guidance, and control system utilizes an Optical Navigation Camera, a Light Detection And Ranging, a Laser Range Finder, and Fan Beam Sensors. It is able to autonomously decide each move on its own by measuring the distance to and the shapes of the asteroid surface using the ONC and LIDAR. "How the spacecraft sees the terrain depends on where the camera is with respect to [the asteroid]," Hayabusa Project Manager Jun'ichiro Kawaguchi has told The Planetary Society. "This may have caused the spacecraft [to be] at a loss for what the target direction [was]."), but aborted mid-way through when it was several hundred meters from the surface.) Since it takes about 17 minutes for messages to be relayed from the mission controller on Earth to Hayabusa, the spacecraft must carry out the descent and landing tasks autonomously, so once Hayabusa begins a flight down close to the asteroid, it is on its own. For this reason alone, the mission's success over the weekend was no small accomplishment. Not all of Hayabusa's maneuvers on the weekend, though, met with success. During the descent activities, Hayabusa released MINERVA, a tiny lander that was to hop around the asteroid taking measurements and pictures. All went well with the release, but the lander did not get to its destination on the surface. Kawaguchi has told The Planetary Society that data they'd obtained indicated that Hayabusa was not getting all the necessary information at the right time from its instruments, and as a result "MINERVA was released with the ascent velocity slightly higher than escape velocity." He also said they had no "definite evidence" that MINERVA hit the surface. Although MINERVA was unable to carry out its duties on the asteroid, the team was able to communicate with the lander after its release, said Kawaguchi, and was glad the robot "functioned normally" and "was delivered to the Itokawa vicinity." Moreover, "the MINERVA camera photographed Hayabusa as it separated" and the Hayabusa camera captured MINERVA flying away. Both images, he added, were "transmitted and relayed to the ground" and will be released soon. Hayabusa will still attempt the touch-and-go landing to collect a sample of the asteroid's surface material, slated on November 25, Junichiro Kawaguchi told The Planetary Society, but this date may now change. Community Email This Article Comment On This Article Related Links JAXA The Planetary Society SpaceDaily Search SpaceDaily Subscribe To SpaceDaily Express Asteroid and Comet Mission News, Science and Technology
NASA'S Spitzer Finds Possible Comet Dust Around Dead Star
Pasadena CA (SPX) Jan 12, 2006NASA's Spitzer Space Telescope has spotted what may be comet dust sprinkled around the white dwarf star G29-38, which died approximately 500 million years ago. |
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