NASA’s Kepler Space Telescope Retires After Nine Years of Planet Discovery

NASA’s most prolific planet-hunter is powering down after nearly a decade of revealing the diversity of our galaxy’s planets.

The Kepler space telescope will be retired after running out of fuel nine years after its initial launch, the space agency announced Tuesday. But the innovative spacecraft enjoyed an illustrious career, discovering as many as 2,600 planets and inspiring new fields of research, NASA said. Among its chief insights: that planets far outnumber stars.

“As NASA’s first planet-hunting mission, Kepler has wildly exceeded all our expectations and paved the way for our exploration and search for life in the solar system and beyond,” said Thomas Zurbuchen of NASA’s Science Mission Directorate. “Its discoveries have shed a new light on our place in the universe, and illuminated the tantalizing mysteries and possibilities among the stars.”

The probe’s retirement was not unexpected. Kepler has been running out of fuel for months, according to Space.com. In the lead-up to its impending retirement, “scientists pushed Kepler to its full potential” by preemptively powering down the spacecraft several times to extend its lifespan. It will be deactivated while in its current orbit of the sun, far from Earth, NASA said.

Launched in March 2009, the $600 million Kepler mission searched the night sky for Earth-like planets using what’s called the “transit method.” The probe’s camera measured changes in the brightness of 150,000 stars in one patch of sky to identify alien planets, including ones that could potentially be inhabited by humans.

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In 2013, mechanical errors made Kepler too unstable to continue its precision surveys. But scientists came up with a workaround, “K2,” that pivoted the probe’s field of view every three months and allowed it to survey more than 500,000 stars.

Over the course of its nine years, Kepler identified 2,662 planets and 61 supernovae on just 3.12 gallons of fuel. Its discoveries also supported nearly 3,000 scientific papers. Scientists said that Kepler’s data will support further research for a decade to come.

“We know the spacecraft’s retirement isn’t the end of Kepler’s discoveries,” said Jessie Dotson, Kepler’s project scientist at NASA’s Ames Research Center in California. “I’m excited about the diverse discoveries that are yet to come.”