Kepler, NASA’s vaunted planet-hunting space telescope, has run out of maneuvering fuel and is being retired, the space agency announced on Tuesday.

After nine and a half years in orbit, 530,506 stars observed and 2,662 planets discovered around other stars, the little spacecraft will be left to drift forever around the sun. Astronomers mourned the loss but celebrated a mission that changed their lives and enlarged the universe and its possibilities.

“Kepler has truly opened a new vista in astronomy,” said William Borucki, a physicist at NASA’s Ames Research Center in Mountain View, Calif., who led the Kepler mission until his retirement in 2015. “We have shown there are more planets than stars in our galaxies.”

Many of these planets, he said, may be just warm enough that they could have liquid water on their surface, “a situation conducive to the existence of life.”