- Kepler telescope in emergency mode 75 million miles away
- "Emergency mode is the lowest operational mode and is fuel intensive," NASA says
(CNN)NASA's Kepler spacecraft is in trouble -- far, far away.
The telescope that searches for habitable planets in outer space went into emergency mode 75 million miles away from home, leaving engineers scrambling.
Mission engineers discovered Kepler was in distress during a scheduled contact Thursday. In emergency mode, Kepler burns through its power supply faster, making recovering it a priority.
"Emergency mode is the lowest operational mode and is fuel intensive," NASA said.
Fixing the telescope is a challenge at such a far distance. Kepler's signals don't travel instantaneously, which slows down communication with ground command.
"Even at the speed of light, it takes 13 minutes for a signal to travel to the spacecraft and back," NASA said.
Earth's older cousin
Since NASA launched the Kepler telescope in 2009, it's been one busy spacecraft.
Its goal is to survey the Milky Way to determine how many stars in our galaxy might have habitable planets, according to NASA.
So many exoplanets
Exoplanets --- or planets orbiting other stars -- are a dime a dozen. But Kepler goes the extra mile to determine whether they are habitable.
Just last year, the Kepler mission confirmed a planet in the "habitable zone" around a sun-like star -- which NASA referred to as Earth's older cousin.
During its first mission completed in 2012, Kepler detected nearly 5,000 exoplanets. More than 1,000 have been confirmed, according to NASA.
Two years ago, NASA began Kepler's second mission.
Under this mission, it searches for exoplanets and research opportunities to study young stars and other astronomical objects.
Kepler is not new at this trouble thing. In 2012, it lost one of its four wheels used for balancing the spacecraft.