Launched in 2009 on a $600 million mission that's already been extended through 2016, the telescope has been experiencing issues with one of the wheels for some time. Wheel No. 2 has been turned off for a while, and earlier this year, managers on Earth noticed another stuck wheel, so they put Kepler in park and hoped the kink would work itself out. On May 12, Kepler put itself into safe mode when it noticed it was drifting out of position. When NASA woke it up Tuesday, May 14, telemetry indicated wheel No. 4 wasn't moving, despite commands for it to spin.