While the malfunction is serious, NASA officials were not ready Wednesday to declare the mission over.
The goal now is to place the craft in an operating mode that reduces the use of its thrusters in order to preserve fuel and "take the time to figure out what to do next," he said.
Kepler was launched in March 2009 as a kind of planetary census taker. The mission's aim is to observe the same 170,000 stars in a hunt for rocky planets orbiting in their stars' habitable zones – roughly defined as a distance that leaves a planet's surface not too hot or not too cold, but just right for liquid water to persist on its surface. Liquid water is a key prerequisite for organic life.
To date, Kepler has found Earth-mass planets. And it has found larger, super-Earths orbiting in their star's habitable zones. The Kepler team has yet to uncover its ultimate planets. But after bagging more than 2,700 planet-candidates so far, finding the first "just right" extra-solar planet isn't far off, says William Borucki, the mission's lead scientist.
"I'm absolutely delighted that we've got all this data," he said at the briefing. "The mission was designed for four years. It operated four years. It gave us excellent data for four years. On the other hand, I would have been even happier if it continues another four years."