"The spacecraft is nearly 75 million miles from Earth, making the communication slow," mission manager Charlie Sobeck said. "Even at the speed of light, it takes 13 minutes for a signal to travel to the spacecraft and back."
The last regular contact with the spacecraft was April 4, when the spacecraft was in good health and operating as expected, Sobeck said.
Kepler completed its prime mission in 2012, detecting more than 1,000 confirmed planets throughout the solar system. The spacecraft began a new mission in 2014 called K2, discovering other astronomical objects including stars and supernovae.