Space telescope Kepler is retiring from its planet hunting duties, after having successfully confirmed 135 planets and identified almost 3,500 possible planets since its launch in 2009.

The $600 million space exploration mission is being halted as NASA is abandoning repair of the telescope. The Kepler space probe has been out of use since May, having suffered damage to its pointing system.

Goodbye Kepler as NASA Halts Telescope Repairs

Since then, the American space agency has been trying to find a solution to fix the reaction wheels, which are used to aim the telescope with precision. All tests since then have failed and the telescope is now left with only two out of four reaction wheels that are still functioning. Kepler would need at least three of the wheels to set its aim accurately.

But two out of four functioning wheels does not mean the space telescope will be decommissioned. NASA is now looking at other possible uses for the spacecraft. According to the deputy manager of the Kepler project, Charlie Sobeck, the telescope can be aimed with the help of the two wheels and the thrusters, but will not have the same accuracy.

Launched in March 2009, the Kepler space probe has already exceeded the expected lifespan of three and a half years and according to Sobek, it still has enough fuel to last for several more years if it is used carefully.

Its main mission was to find other planets and especially to identify worlds the size of Earth that could support life. So far, Kepler has confirmed a total of 135 planets and found nearly 3,500 other possible planets. Scientists still have to go through all the data collected over the last couple of years, and expect to confirm even more planets.

Kepler-22b was the first habitable zone planet confirmed by the Kepler mission.

Kepler-22b was the first habitable zone planet confirmed by the Kepler mission.

Based on data retrieved by the space telescope, scientists were able to determine that there are at least 17 billion exoplanets the size of Earth in the Milky Way. Two planets located about 1,200 light years away are believed to be the most likely candidates for supporting life.

Over the coming months, the Kepler team will try to carefully assess the spacecraft’s abilities and possible uses, after which they will decide which solution would be practical and cost-effective. Possible solutions for the space telescope include tracking comets and asteroids or looking for supernovae.

[Images via universetoday & NASA]