NASA is saying “goodnight” to its pioneering Kepler telescope, which a few months shy of its 10th birthday but years past its expected lifespan, has finally run out of fuel.

The planet-hunting spacecraft, credited with discovering thousands of exoplanets, or planets beyond our solar system, will be retired and left in its current orbit, a safe distance from Earth, NASA announced Tuesday. Kepler’s transmitter and other instruments will be shut down in the coming days.

After spending nine years in deep space and revealing that our galaxy🌀 contains more planets 🔵⚫️🔴 even than stars ✨, NASA's Kepler space telescope has run out of fuel. https://t.co/Vv0lbhj1ti pic.twitter.com/Z7lAKcmNr7 — NASA Planetquest (@PlanetQuest) October 30, 2018

Kepler was launched in March 2009 with enough fuel to keep it going for at least six years, according to The Verge. It far surpassed expectations, however, collecting data in deep space for more than nine years. In all, the telescope made more than 2,600 exoplanet discoveries, NASA said.

“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,” Thomas Zurbuchen, associate administrator of NASA’s science mission directorate, said in a statement. “Not only did it show us how many planets could be out there, it sparked an entirely new and robust field of research that has taken the science community by storm. Its discoveries have shed a new light on our place in the universe, and illuminated the tantalizing mysteries and possibilities among the stars.”

.@NASAKepler leaves a legacy of more than 2,600 #exoplanet discoveries 💫 from outside our solar system, many of which could be promising places for life. https://t.co/sC3ecp4fPK pic.twitter.com/7qiWud3vaK — NASA Planetquest (@PlanetQuest) October 30, 2018

Kepler searched for alien worlds by looking out for their transits, which are dips in the brightness of stars that could indicate orbiting planets.

“It was like trying to detect a flea crawling across a car headlight when the car was 100 miles away,” William Borucki, who led the original Kepler science team, told AP of the telescope’s technology,

When Kepler’s stabilizing equipment began malfunctioning in 2013, NASA feared it was doomed. But the mission team managed to salvage the telescope after figuring out how to use the pressure of sunlight to balance the spacecraft. Once the fix was made, NASA approved a new mission for the spacecraft, dubbed K2.

Kepler continued to hunt for planets during its K2 phase. As Space.com notes, the spacecraft also studied “a variety of cosmic objects and phenomena, from comets and asteroids in our own solar system to faraway supernova explosions.”

What has the @NASAKepler space telescope achieved during its time in space? Take a look at the numbers: https://t.co/Ei3m5dSdvh pic.twitter.com/zIgJw0gRSX — NASA Kepler and K2 (@NASAKepler) October 30, 2018

In April, a spacecraft successor to Kepler ― NASA’s Transiting Exoplanet Survey Satellite, or TESS ― was launched.

“TESS builds on Kepler’s foundation with fresh batches of data in its search of planets orbiting some 200,000 of the brightest and nearest stars to the Earth, worlds that can later be explored for signs of life,” NASA said.

Calling Kepler’s mission “stunningly successful,” TESS project scientist Padi Boyd told AP that the retired telescope has shown us that “we live in a galaxy that’s teeming with planets.”

Boyd also noted that our exploration of the cosmos has only just begun.

“We’re ready to take the next step to explore those planets,” Boyd said.