Kepler planet hunter ends operations after exhausting fuel

Kepler Space Telescope

The US Kepler Space Telescope has run out of fuel and is being retired after a nine and a half year mission during which it discovered more than 2,600 planets outside the Solar System, the National Aeronautics and Space Administration (NASA) said on Wednesday. The spacecraft had been in what NASA called a "no-fuel-use" safe mode since it was contacted by controllers October 19.

Kepler discovered 2,681 planets outside our solar system and even more potential candidates.

"We have shown there are more planets than stars in our galaxy, that many of these planets are roughly the size of the Earth and some, like the Earth, are at the right distance from their star that there could be liquid water on the surface, a situation conducive to the existence of life", Borucki said.

"Before we launched Kepler, we didn't know if planets were common or rare in our galaxy", Paul Hertz, NASA's Astrophysics Division director, said in a press call Tuesday.

"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, DC.

Four years into the mission, after the primary mission objectives had been met, mechanical failures temporarily halted observations.

Telescope Kepler was launched in 2009, its task is the search for exoplanets. In 2017, its mission at Ceres was extended again to study the dwarf planet from altitudes as low as 22 miles (35 kilometers) above Ceres' surface, with the main goal of understanding the evolution of Ceres and possibly active geology. It took the first survey of planets in our Galaxy and became NASA's first mission to detect Earth-size planets in the habitable zones of their stars.

"Because of fuel exhaustion, the Kepler spacecraft has reached the end of its service life", he said.

Signals that fuel was almost out were seen two weeks ago and scientists were able to get all the data from Kepler down to Earth before it completely ran dry.

The next-generation planet hunter space telescope for Nasa, TESS, launched in April and will survey far more cosmic terrain than Kepler.

Bill Borucki, the mission's retired principal investigator, compared the task to "trying to detect a flea crawling across a vehicle headlight when the auto was 100 miles away".

An artist's impression of a solar system found by the Kepler space telescope. That is, a small dip in the light from a star as the planet passed in front of it.

The far more advanced James Webb Space Telescope, scheduled to lift off in 2021, should be able to reveal more about planets' mass, density and the makeup of their atmosphere - all clues to habitability. The first data from TESS is already being sent to Earth and analyzed.

It also showed us the diversity of planets and planetary systems out there, some of which are very different than ours.

"Because of Kepler, what we think about our place in the universe has changed", Hertz said.

"We know the spacecraft's retirement isn't the end of Kepler's discoveries", according to Jessie Dotson, Kepler's project scientist at the Ames Research Center.

Kepler hands off the baton to TESS now, NASA said.

NASA's Kepler mission has discovered a world where two suns set over the horizon instead of just one. Approval for this new phase of Kepler's life was given by NASA on May 16, 2014.