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Kepler space telescope, reborn, surprising critics and discovering new planets

Kepler isn't dead after all.

Launched in 2009, the famous space telescope tasked with finding Earth-like planets has identified more than 1,000 exoplanets among 4,175 candidates it's discovered. After completing its primary mission in 2012, NASA extended its life by four years hoping to build on its early success.

But things started to go wrong almost immediately. A hardware glitch in 2012 and a second one a year later left two of its four spinning reaction wheels inoperable. The wheels, which operate like gyroscopes, allowed the telescope to aim and lock on a target. With no way to fix the wheels, the mission appeared to be over.

"We had very prominent members of our own science team that were saying it's dead, too bad," Steve Howell, project scientist, NASA K2 Mission, told CBS News. "They were giving it last rites and all kinds of things like that."

But Howell and others were not ready to abandon the telescope.

NASA scientists teamed up with colleagues at Ball Aerospace,which built the spacecraft, to use the two reaction wheels that still worked and go in search of a "third force to kind of balance those two."

"It turns out we used the light from the sun pushing against the solar panels," Howell said. "That provided enough of a force and then we take the other two reaction wheels and kind of push against that force. We can now balance the telescope again and point it pretty specifically in one direction."

Thus rebooted, the second act of Kepler was born. The mission was relaunched in May 2014 under the name K2 and will pick up where the scope left off.

But K2 won't have the same reach as the original Kepler. Because its solar panels have to be directed toward the sun in a symmetrical way to achieve balance, the telescope searches a much more limited area. It scans what is known as the ecliptic, which is the path the sun appears to take through the sky as a result of the Earth's revolution. Stargazers are familiar with the trajectory, which passes through the 12 constellations of the Zodiac.

"Instead of being able to point at a field for four years, we can only look at a given field for 85 days," Howell said. "All the fields along this band in the sky. We just march along the band in the sky looking at one field for three months and then another field for about three months."

K2 "will never be the same," he added, and never find as many planets because it can't match the breadth of Kepler which monitored 150,000 stars every 30 minutes for four years. Instead, K2 only looks at "brighter and closer stars, things where we can do a lot of follow up study and actually start to characterize the planets we find."

K2 also faces other limitations, namely that will eventually it will run out of fuel. Unlike the first mission, K2 must use fuel to reorient telescope so that it points to Earth and allows scientists to download data and upload commands for it to go and look at the next field.

"Once the fuel runs out even if all the hardware is still working great, we will be done. We won't be able to do these maneuvers anymore," Howell said. "K2 from today could operate for another three or four years."

Since K2 began last year, it's already proving its worth with two significant discoveries.

The first find announced in December was a single planet in a nine-day orbit around a K star - a star that is about two-thirds the size of the sun but about the same age and composition.

Then this month, scientists reported that K2 had identified its first multi-planet system, three planets orbiting a star about 150 light-years away in the constellation Leo. Because the system is relatively close, Howell said scientists will be able to study it in detail to better understand whether these planets have an atmosphere and what that atmosphere contains.

The planets are two-and-half times the size of earth and orbit a star about half the size and mass of our sun. The outermost planet orbits on the warm edge of the habitable zone, the distance from a star where liquid water might exist on the surface of an orbiting planet, thus providing the right conditions for life.

"The mission has extended the telescope's search capability to a new part of the sky, marking the first K2 exoplanet discovery less than a month ago, and now the possible discovery of the first K2 multiple-planet system," said Charles Sobeck, Kepler project manager at NASA's Ames Research Center in Moffett Field, Calif.

Steve Kawaler, an Iowa State University professor of physics and astronomy who was part of the team that this month discovered an 11.2-billion-year-old star with at least five Earth-size planets by using the original Kepler data, said he was impressed with how NASA worked with the scientific community to determine what the future held for K2 as they were coming up with a fix.

"The way they figured out how to use it, in its somewhat impaired state, is impressive," he said. "They asked all astronomers what would you do if you could this, do that or the other thing. The community as a whole responded with some brilliant ideas for the kind of science that you could do. It wasn't necessarily finding new planets but it was a way of doing science which you couldn't do with a telescope on the ground."

Many astronomers admit they are surprised that Kepler had a second act but are excited about its potential given how many planets Kepler found the first time around.

Lynn Hillenbrand, an astronomy professor at the California Institute of Technology who has specialized the past 20 years in star and planet formation and stellar astrophysics, called the Kepler breakdown a "blessing in disguise" which is allowing for "new kinds of planet searches to be done."

"There was a brilliant engineering innovation by the Kepler engineers to use sunlight pressure on the spacecraft to stabilize it," Geoff Marcy, the Alberts Chair in the Department of Astronomy at U.C. Berkeley, told CBS News.

"This breakthrough saved Kepler from the grave," he said. "I'm blown away that Kepler lives on. Its resurrection is a tribute to the creativity of the NASA engineers and to the brilliance of the young bucks who are writing data analysis code to make up for the jiggling of the Kepler spacecraft."

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