The deep space mission's end is not unexpected, as low fuel levels had been noted in July. During the near-decade of its life, Kepler found evidence of more than 2,600 planets located beyond our solar system. "Now we know there are billions of planets that are rocky like the Earth and are orbiting their stars in the habitable zone, or the Goldilocks zone, where their temperatures might be conducive to water on the surface".
The space agency says it has chose to retire Kepler while it is located in its present orbit, which it describes as safe and away from Earth.
Voyage of discovery: Kepler was NASA's first planet-hunting mission and it was wildly successful: so far it has discovered 2,662 exoplanets in our galaxy. "Its discoveries have shed a new light on our place in the universe, and illuminated the tantalizing mysteries and possibilities among the stars", said Zurbuchen.
The most common size of planet Kepler found doesn't exist in our solar system - a world between the size of Earth and Neptune - and we have much to learn about these planets.
Nasa says Kepler's mission may be over but its discoveries will be studied for years to come.
Kepler's mission was to determine if earth-like planets are common or rare outside our own solar system and was originally meant to only last three-and-a-half years.
"Now that we know planets are everywhere, Kepler has set us on a new course that's full of promise for future generations to explore our galaxy", he added. Originally positioned to stare continuously at 150,000 stars in one star-studded patch of the sky in the constellation Cygnus, Kepler took the first survey of planets in our galaxy and became the agency's first mission to detect Earth-size planets in the habitable zones of their stars.
Four years into the mission, the main goals had been met, but mechanical failures put a sudden end to future observations.More news: Mourinho escapes FA charge over abusive language use
Mission planners reworked Kepler's mode of operation to point at other parts of the sky, expanding its list of targets to 500,000 stars.
Since that time, NASA changed the craft's mission to adjust to the telescope's new normal, calling the updated mission K2. "We're confident that TESS is going to find thousands more planets, just like Kepler did".
Nasa has declared its elite planet-hunting spacecraft dead. Researchers used these observations to then search for periodic dimming events around each star, which indicates an exoplanet has passed in front of the star. NASA's Jet Propulsion Laboratory in Pasadena, California, managed Kepler mission development. The first data from TESS is already being sent to Earth and analyzed.
Nasa has switched off the Kepler space telescope permanently after announcing that it had "exceeded all expectations".
A marvel of engineering The $600 million Kepler mission found alien worlds using the "transit method", picking up on tiny brightness dips caused when orbiting planets cross a star's face - as seen from Kepler's perspective. This light would allow astronomers to take the spectrum of a planet and look for signs of habitability - and life.
There's poetry in Kepler's ability to make us feel both small and also so connected to the rest of our universe.
As of today, Kepler has detected 2,681 confirmed planets, plus 2,899 other candidates yet to be confirmed, said Kepler project scientist Jessie Dotson.