Kepler, launched in 2009 and named for Johannes Kepler, was retired in October 2018 after running out of fuel. The telescope spent nearly a decade in solar orbit (with an extended K2 mission after reaction-wheel problems) and produced a striking final “last light” image. Kepler discovered over 2,600 confirmed exoplanets and helped show that roughly 20–50% of Sun-like stars may host small, potentially rocky planets in habitable zones. Its full dataset is archived at the Barbara A. Mikulski Archive for Space Telescopes and continues to fuel new research.
What Happened to NASA's Kepler Space Telescope? Mission End, Discoveries, and Legacy
Kepler, launched in 2009 and named for Johannes Kepler, was retired in October 2018 after running out of fuel. The telescope spent nearly a decade in solar orbit (with an extended K2 mission after reaction-wheel problems) and produced a striking final “last light” image. Kepler discovered over 2,600 confirmed exoplanets and helped show that roughly 20–50% of Sun-like stars may host small, potentially rocky planets in habitable zones. Its full dataset is archived at the Barbara A. Mikulski Archive for Space Telescopes and continues to fuel new research.
18:48, 09.11.2025Science
What happened to Kepler?
Launched in 2009, NASA's Kepler Space Telescope was built to find Earth-sized planets orbiting other stars. Named for 17th-century astronomer Johannes Kepler, the spacecraft spent nearly a decade scanning the same patch of sky and transformed our understanding of exoplanets.
Why it stopped operating
Kepler wasn't lost to a dramatic accident — it ran out of fuel. The mission also faced hardware problems: failures of two reaction wheels in 2012–2013 made its original pointing method impossible. Engineers ingeniously repurposed the craft for an extended mission called K2, using solar pressure to help stabilize pointing and continue observations from 2014 onward. Ultimately, by October 2018, mission teams confirmed Kepler had exhausted the fuel required for attitude control and communications, so NASA formally decommissioned the spacecraft.
Final steps and current status
Before retirement, Kepler was given a final “last light” image — a memorable farewell — and controllers shut down its instruments and communications to preserve orbital safety. Kepler remains in a stable solar orbit (it orbits the Sun, not Earth) and will be a piece of inert hardware drifting safely for decades.
Major achievements
Kepler revolutionized exoplanet science. It is credited with discovering more than 2,600 confirmed exoplanets and thousands of additional candidates. Kepler data led to estimates that roughly 20–50% of Sun-like stars may host small, potentially rocky planets in their star's habitable zone — dramatically increasing the plausibility that Earth-like worlds are common in our galaxy.
Data and legacy
All of Kepler's observations are publicly archived at the Barbara A. Mikulski Archive for Space Telescopes (MAST), where astronomers and citizen scientists continue to mine the data for new discoveries. Kepler paved the way for follow-up missions and instruments — including TESS, the James Webb Space Telescope, and continued work with Hubble — and its legacy endures in the many studies and discoveries still emerging from its dataset.
Bottom line: Kepler was retired because it ran out of fuel after a long, highly successful mission that fundamentally changed our view of planets beyond the Solar System.