NASA is struggling to revive its fading Kepler space probe, which has entered into a state of emergency more than 120 million kilometers from Earth.
The space agency says its last contact with the aging planet hunter was one week ago. Ground controllers were preparing to direct Kepler toward the center of the Milky Way. It says the probe was showing no signs of distress at that time.
Since then, NASA says Kepler has entered what it calls the "lowest operational mode," and says saving it from oblivion is the Kepler team's top priority.
NASA launched Kepler in 2009 and it has detected more than 1,000 confirmed planets outside our solar system.
Its primary mission to hunt for planets ended in 2012, but despite numerous breakdowns, NASA has always been able to resuscitate Kepler and keep it going.