14 DAY TRIAL // The Japanese space probe Hayabusa is supposed to bring back to Earth some asteroid dust hopefully gathered from Itokawa.
However, the probe has had its share of problems and scientists were concerned that the spacecraft may not be able to complete its mission. But tests of spacecraft's four ion engines have now shown that it will probably have enough power to make it back to Earth. The craft is planned to return in June 2010 and to drop a capsule in the Australian outback.
Hayabusa should have collected samples from the asteroid by firing pellets into its surface and than scooping up the resulting debris. The two landings happened in November 2005 but apparently the pellets never fired because the craft's onboard computer sent conflicting signals to its collection instruments. Nonetheless, mission officials hope to bring the spacecraft back to Earth in case some asteroid dust had slipped into its collection chamber by chance.
But in late November one of its fuel thrusters leaked and the probe went spinning out of control. Some contact with the craft was restored at the end of January and mission controllers realized that all of the fuel in the 12 chemical thrusters had seeped away. These chemical thrusters were already compensating for the loss of two of three stabilizing reaction wheels a few months earlier, so after the leak the craft's only hope were its four ion engines.
Scientists had worried that the fuel leak and the resulting spin damaged the engines, but apparently that didn't happen. They have now tested two of the engines and found they are "in very good shape", says mission manager Jun'ichiro Kawaguchi. He said that "the return cruise is possible even with two engines."
A third engine will be tested in January 2007 when the spacecraft's orbit takes it closer to the Sun, making it less prone to damage from the cold of space. The fourth engine will be reserved as a spare and will therefore not be tested.
Kawaguchi says mission controllers are having no problems communicating with or operating the spacecraft. However, they are not in the clear as yet: "The spacecraft was seriously injured and operating it and making it resume cruise are still very hard things."
Image credit: JAXA