The Kepler space telescope has run out of fuel and will be retired after a 9½ mission in which it detected thousands of planets beyond our solar system and boosted the search for worlds that might harbor alien life, NASA said on Tuesday.

Currently orbiting the sun 94 million miles (156 million km) from Earth, the spacecraft will drift farther from our planet when mission engineers turn off its radio transmitters, the U.S. space agency said.

The telescope laid bare the diversity of planets that reside in our Milky Way galaxy, with findings indicating that distant star systems are populated with billions of planets, and even helped pinpoint the first moon known outside our solar system.