(CNN) —
NASA’s Kepler Space Telescope has run out of fuel, and its mission has come to an end 94 million miles from Earth, the agency announced Tuesday. The deep space mission’s end is not unexpected, as low fuel levels had been noted in July.
The nine-year planet-hunting mission discovered 2,899 exoplanet candidates and 2,681 confirmed exoplanets in our galaxy, revealing that our solar system isn’t the only home for planets.
Kepler allowed astronomers to discover that 20% to 50% of the stars we can see in the night sky are likely to have small, rocky, Earth-size planets within their habitable zones – which means that liquid water could pool on the surface, and life as we know it could exist on these planets.
The final commands have been sent, and the spacecraft will remain a safe distance from Earth to avoid colliding with our planet.
“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, associate administrator of NASA’s Science Mission Directorate in Washington. “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.”
The Kepler mission was named in honor of 17th century German astronomer Johannes Kepler, who discovered the laws of planetary motion.
Kepler, the telescope, reached more than twice its initial target, accomplishing original mission goals and seizing unexpected opportunities to answer questions about our galaxy and the universe, according to Charlie Sobeck, project system engineer at NASA’s Ames Research Center.
Photos: Weird and wonderful planets beyond our solar system
PHOTO:
NASA/JPL-Caltech
This illustration shows the metaphorical measuring of the density of each of the seven planets in the nearby TRAPPIST-1 system. New measurements have revealed the most precise densities yet for these planets and they're very similar -- which means they also likely have similar compositions.
Photos: Weird and wonderful planets beyond our solar system
PHOTO:
L. Calçada/ESO
This artist's illustration shows the view from the furthest planet in the TOI-178 system.
Photos: Weird and wonderful planets beyond our solar system
PHOTO:
W. M. Keck Observatory/Adam Makarenko
This artist's illustration shows TOI-561b, one of the oldest and most metal-poor planetary systems discovered yet in the Milky Way galaxy. Astronomers found a super-Earth and two other planets orbiting the star.
Photos: Weird and wonderful planets beyond our solar system
PHOTO:
ESA/Hubble/M. Kornmesser
This massive and distant exoplanet, called HD106906 b, has an elongated and angled orbit that causes it to take 15,000 Earth years to complete one lap around its twin stars.
Photos: Weird and wonderful planets beyond our solar system
PHOTO:
Jan Skowron/Astronomical Observatory, University of Warsaw
This is an artist's impression of a free-floating rogue planet being detected in our Milky Way galaxy using a technique called microlensing. Microlensing occurs when an object in space can warp space-time.
Photos: Weird and wonderful planets beyond our solar system
PHOTO:
ESA
This is an artist's impression of exoplanet WASP-189 b orbiting its host star. The star appears to glow blue because it's more than 2,000 degrees hotter than our sun. The planet, which is slightly larger than Jupiter, has a tilted orbit around the star's poles rather than its equator.
Photos: Weird and wonderful planets beyond our solar system
PHOTO:
NASA's Goddard Space Flight Ce
For the first time, an exoplanet has been found orbiting a dead star known as a white dwarf. In this artist's illustration, the Jupiter-sized planet WD 1856 b orbits the white dwarf every day and a half.
Photos: Weird and wonderful planets beyond our solar system
PHOTO:
Shim/ASU/Vecteezy
This illustration shows a carbon-rich planet with diamond and silica as ts main minerals. Water can convert a carbon-rich planet into one that's made of diamonds. In the interior, the main minerals would be diamond and silica (a layer with crystals in the illustration). The core (dark blue) might be made of an iron-carbon alloy.
Photos: Weird and wonderful planets beyond our solar system
PHOTO:
European Southern Observatory/Bohn et al.
This image shows a young sun-like star being orbited by two gas giant exoplanets. It was taken by the SPHERE instrument on European Southern Observatory's Very Large Telescope. The star can be seen in the top left corner, and the planets are the two bright dots.
Photos: Weird and wonderful planets beyond our solar system
PHOTO:
Mark Garlick/University of Warwick
This artist's impression shows a Neptune-sized planet in the Neptunian Desert. It is extremely rare to find an object of this size and density so close to its star.
Photos: Weird and wonderful planets beyond our solar system
PHOTO:
Mark Garlick
This is an artist's impression of the multiplanetary system of newly discovered super-Earths orbiting a nearby red dwarf star called Gliese 887.
Photos: Weird and wonderful planets beyond our solar system
PHOTO:
NASA's Goddard Space Flight Center/Chris Smith (USRA)
The newly discovered exoplanet AU Mic b is about the size of Neptune.
Photos: Weird and wonderful planets beyond our solar system
PHOTO:
European Southern Observatory/M. Kornmesser
This artist's impression shows a view of the surface of the planet Proxima b orbiting the red dwarf star Proxima Centauri, the closest star to the Solar System. Proxima b is a little more massive than the Earth.
Photos: Weird and wonderful planets beyond our solar system
PHOTO:
Jack Madden/Carl Sagan Institute/Cornell University
This is an artist's illustration of an exoplanet's atmosphere with a white dwarf star visible on the horizon. The starlight of a white dwarf filtered through the atmosphere of an exoplanet that's orbiting it could reveal if the planet has biosignatures.
Photos: Weird and wonderful planets beyond our solar system
PHOTO:
Adam Makarenko/W. M. Keck Observatory
This is an artist's illustration of the Kepler-88 planetary system, where one giant exoplanet and two smaller planets orbit the Kepler-88 star. The system is more than 1,200 light-years away.
Photos: Weird and wonderful planets beyond our solar system
PHOTO:
NASA/Ames Research Center/Daniel Rutter
This is an illustration of newly discovered exoplanet Kepler-1649c orbiting around its host red dwarf star.
Photos: Weird and wonderful planets beyond our solar system
PHOTO:
M. Kornmesser/ESO
This artist's illustration shows the night-side view of the exoplanet WASP-76b, where iron rains down from the sky.
Photos: Weird and wonderful planets beyond our solar system
PHOTO:
Robin Dienel/Carnegie Institution for Science
This is an artist's concept of a ringed planet passing in front of its host star. It shows how "puffy" a ringed planet may look to us from afar.
Photos: Weird and wonderful planets beyond our solar system
PHOTO:
Michelle Kunimoto
The sizes of the 17 new planet candidates, seen here in orange, are compared to colorized representations of Mars, Earth and Neptune. The green planet is KIC-7340288 b, a rocky planet in the habitable zone of its star.
Photos: Weird and wonderful planets beyond our solar system
PHOTO:
courtesy Amanda Smith
Artist's impression of K2-18b. CREDIT Amanda Smith
Photos: Weird and wonderful planets beyond our solar system
PHOTO:
NASA/JPL-Caltech/R. Hurt
This is an artist's illustration a massive planet orbiting a cool, young star. In the case of the newly discovered system, the planet is 10 times more massive than Jupiter, and the orbit of the planet is nearly 600 times that of Earth around the sun.
Photos: Weird and wonderful planets beyond our solar system
PHOTO:
R. Hurt (IPAC)/NASA/JPL-Caltech
Welcome to the KELT-9 system. The host star is a hot, rapidly rotating A-type star that is about 2.5 times more massive and almost twice as hot as our sun. The hot star blasts its nearby planet KELT-9b with massive amounts of radiation, leading to a daylight temperature of 7800 degrees Fahrenheit, hotter that most stars and only 2000 degrees cooler than the sun.
Photos: Weird and wonderful planets beyond our solar system
PHOTO:
Lorenzo Santinelli
This is an artist's rendering of the Proxima Centauri planetary system. The newly discovered super-Earth exoplanet Proxima c, on the right, has an orbit of about 5.2 Earth years around its host star. The system also comprises the smaller Proxima b, on the left, discovered in 2016. Illustration by Lorenzo Santinelli.
Photos: Weird and wonderful planets beyond our solar system
PHOTO:
Robin Dienel/Courtesy of the Carnegie Institution for Science
This is an artist's concept of GJ180d, the nearest temperate super-Earth to us with the potential to support life.
Photos: Weird and wonderful planets beyond our solar system
PHOTO:
NASA/JPL-Caltech
An illustration of WASP-12b as it spirals in a death dance towards its star. The planet will meet its end in three million years.
Photos: Weird and wonderful planets beyond our solar system
PHOTO:
NASA's Goddard Space Flight Center
TOI 700 d is the first potentially habitable Earth-size planet spotted by NASA's planet-hunting TESS mission.
Photos: Weird and wonderful planets beyond our solar system
PHOTO:
NASA's Goddard Space Flight Center/Chris Smith
TOI 1338 b is silhouetted by its two host stars, making it the first such discovery for the TESS mission. TESS only detects transits from the larger star
Photos: Weird and wonderful planets beyond our solar system
PHOTO:
Friedlander-Griswold/GSFC/NASA
This artist's illustration shows a wet exoplanet with an oxygen atmosphere. The red sphere is the M-dwarf star the exoplanet orbits.
Photos: Weird and wonderful planets beyond our solar system
PHOTO:
Friedlander-Griswold/GSFC/NASA
This artist's illustration shows a dry exoplanet with an oxygen atmosphere. The red sphere is the M-dwarf star the exoplanet orbits.
Photos: Weird and wonderful planets beyond our solar system
PHOTO:
NASA/ESA/STSci
This artist's illustration of the Kepler 51 system shows newly discovered super-puff exoplanets, which are also called "cotton candy" exoplanets because they're so lightweight.
Photos: Weird and wonderful planets beyond our solar system
PHOTO:
NASA/Harvard-Smithsonian Center for Astrophysics/D. Aguilar
This artist's concept illustration shows an exoplanet with two moons orbiting within the habitable zone of a red dwarf star.
Photos: Weird and wonderful planets beyond our solar system
PHOTO:
Lynette Cook/SOFIA/NASA
This is an artist's illustration of two exoplanets colliding in a binary star system.
Photos: Weird and wonderful planets beyond our solar system
PHOTO:
Francis Reddy/NASA's Goddard Space Flight Center
This is an artist's illustration of a Neptune-type exoplanet in the icy outer reaches of its star system. It could look something like a large, newly discovered gas giant that takes about 20 years to orbit a star 11 light years away from Earth.
Photos: Weird and wonderful planets beyond our solar system
PHOTO:
Guillem Anglada-Escude/IEEC/SpaceEngine.org
This image shows a comparison of red dwarf star GJ 3512 to our solar system, as well as other nearby red-dwarf planetary systems.
Photos: Weird and wonderful planets beyond our solar system
PHOTO:
ESA/Hubble/M. Kornmesser
This artist's illustration showcases exoplanet K2-18b orbiting its host star. It's currently the only super-Earth exoplanet that has water vapor in its atmosphere and could be within the right temperature to support life.
Photos: Weird and wonderful planets beyond our solar system
PHOTO:
Thibaut Roger/University of Bern
This is an illustration of an exomoon losing mass as it's being pulled around the gas giant it orbits.
Photos: Weird and wonderful planets beyond our solar system
PHOTO:
Adam Makarenko/W. M. Keck Observatory
An illustration shows what the orbit of exoplanet HR 5183 b would look like if it was dropped down in our solar system. It would likely swing from the asteroid belt to out past Neptune, the eighth planet in our solar system.
Photos: Weird and wonderful planets beyond our solar system
PHOTO:
P Rubini/AM Lagrange
At least two giant planets, aged 20 million years at most, orbit the Beta Pictoris star. A disk of dust and gas surrounding the star can be seen in the background.
Photos: Weird and wonderful planets beyond our solar system
PHOTO:
NASA's Goddard Space Flight Center/Chris Smith
This is an artist's interpretation of what super-Earth GJ 357 d might look like. It lies within the habitable zone of its star which is 31 light-years from Earth.
Photos: Weird and wonderful planets beyond our solar system