The days of planet hunting for NASA's hobbled Kepler Space Telescope are in all likelihood over, the space agency said this week.
"Following months of analysis and testing, the Kepler Space Telescope team is ending its attempts to restore the spacecraft to full working order, and now is considering what new science research it can carry out in its current condition," NASA said in a statement on Thursday.
The Kepler team was trying to repair at least one of two failed reaction wheels. They are used to position the spacecraft in order to aim its telescope in its search for Earth-sized exoplanets circling distant stars in the "habitable zone," a distance that scientists believe could support life.
The Kepler space observatory was launched on March 7, 2009 atop a Delta II rocket and spent the next 3.5 years scanning more than 150,000 stars for signs of planetary activity. The spacecraft's primary mission ended last November, but NASA had hoped Kepler could continue on with a more refined search for Earth-like exoplanets as part of an extended four-year mission.
For a time, that seemed like it would work out. Though one of its reaction wheels failed last July, Kepler was identifying planets as recently as this April. But the failure of a second reaction wheel in May hobbled the spacecraft. NASA said at least three of Kepler's four reaction wheels must be operational for the telescope to work properly.
On Aug. 8, NASA engineers concluded that the damaged reaction wheels couldn't be fixed and called off further attempts to do so, the space agency said.
"Kepler has made extraordinary discoveries in finding exoplanets, including several super-Earths in the habitable zone," said John Grunsfeld, associate administrator for NASA's Science Mission Directorate in Washington. "Knowing that Kepler has successfully collected all the data from its prime mission, I am confident that more amazing discoveries are on the horizon."
NASA said the Kepler project team is currently studying ways Kepler can be used for different kinds of scientific research, which should be determined later this year.
"Though the spacecraft will no longer operate with its unparalleled precision pointing, scientists expect Kepler's most interesting discoveries are still to come," the space agency said.
Meanwhile, there is still a mountain of data generated by Kepler over the past several years to sift through, NASA said, so even if the space telescope is no longer able to continue hunting for planets, we can expect to learn a great deal more from its findings for a long time to come.