A three-month effort to return the craft to working order, completed just last week, was unsuccessful, said Kepler deputy project manager Charles Sobeck during a phone call with reporters, the Los Angeles Times reported.
Reaction wheels that help the craft focus on far-off stars “are sufficiently damaged that they cannot sustain spacecraft pointing control for any extended period of time,” he said, adding that the space agency will now focus on figuring out how it might still use the telescope with only two fully functioning reaction wheels.
Scientists who are interested in finding Earth-like planets outside of our solar system have regarded the Kepler mission as a big success. By observing slight dips in the light from distant stars — which correspond to planets “transiting” between their host stars and the telescope’s lens — Kepler has discovered 135 confirmed planets and 3,548 planet candidates.
Scientists are still analyzing Kepler data in search of more exoplanets, including Earth-sized planets orbiting sun-like stars in the “habitable zone” — at a distance where liquid water can exist on the planet’s surface.
William Borucki, Kepler’s science principal investigator, said he expected scientists would find signals from such a planet in the data Kepler has already collected.
“The best is yet to come,” said NASA Astrophysics Division director Paul Hertz.