TWO鈥橲 company, three鈥檚 a crowd. That鈥檚 the mantra that could buy the Hubble Space Telescope some extra time before NASA brings it down to Earth.
The telescope was designed to use three gyroscopes to point and stabilise itself in space, with three more as back-ups. But the gyros regularly break down, and astronauts have already replaced them twice. Now, the 15-year-old observatory has only four working gyros. Barring any decision to replace them, NASA foresees bringing Hubble down to crash into the ocean after they fail.
However, engineers at NASA have now developed software that would allow the telescope to run on only two gyros, leaving two on standby. The first full-scale test was conducted from 20 to 23 February. 鈥淲hen the engineers started writing the software, they had grave doubts,鈥� says Edward Weiler, director of NASA鈥檚 Goddard Space Flight Center in Greenbelt, Maryland. But the test worked so well, 鈥渋t鈥檚 almost embarrassing鈥�, he says.
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According to Weiler, the images Hubble took during the test were 鈥渁lmost indistinguishable鈥� from those taken during regular operations, allaying scientists鈥� concern that the two-gyro system would result in blurry images. If NASA runs Hubble with only two gyros, it could extend the telescope鈥檚 life by a year, possibly until late 2008.
