Earlier this year, it was reported y NASA that its Kepler Observatory was facing dire technical problems as its 'reaction wheels,' which help keep the observatory properly orientated in space, were failing. Problem: shortly after the news of Kepler's troubles broke, a wheel broke. Speaking on the problem as news broke, NASA science chief John Grunsfeld said that Kepler is “not down and out just yet.”
Now, two seasons after the crucial part failed, researchers are saying that Kepler can still be used for hunting alien planets, regardless of its stability. Speaking on the handicapped Kepler, Charlie Sobeck, Kepler's project manager, said that, other than for the reaction wheels, the spacecraft “is in great shape.” In August, NASA issued a call for new mission proposals.
Now, four months after the call for new ideas went out, NASA is seriously considering one of them, dubbed 'K2.'
During its original mission, Kepler stared continuously at more than 150,000 stars in a small patch of sky K2 would take the instrument on a broader view, covering five to 10 times more area by studying four to six "fields" per year, observing each one for a minimum of 40 days but preferably for 70 to 80 days, according to Kepler project scientist Steve Howell. Ideally, Kepler would study 10,000 to 20,000 targets within each field, he added. All of these fields would be roughly in the plane of Earth's orbit because such an orientation would maximize Kepler's compromised pointing ability.
According to Howell, the K2 mission would likely turn up many small exoplanets around small stars, including some in the habitable zone. It could also spot a number of alien worlds around bright stars, which would make good targets for follow-up observation by NASA's James Webb Space Telescope, an $8.8 billion instrument due to launch in 2018.
As an afterthought, Kepler could also gather data about supernova explosions, star formation and solar-system bodies such as asteroids and comets during K2, should it come to pass.
Right now, the Kepler team is currently working on the close-out plan for Kepler's original mission. As of Wednesday, NASA sent the K2 proposal to a vetting stage called "senior review." The space agency had until today to decide whether K2 worth a deeper look. Obviously, that question has been answered in the affirmative. The hope: a decision my mid 2014.
Still, no matter what comes of K2, Kepler's scientific legacy is a rich one as it has, literally, added over 3,500 worlds to our knowable universe.
Speaking on Kepler, Paul Hertz, astrophysics director at NASA Headquarters in Washington, D.C., said that “before we flew Kepler, we didn't know that Earth-sized planets in habitable zones were common throughout our galaxy . . . we didn't know that virtually every star in the sky had planets around them. Now we know that."
For that one accomplishment alone, Kepler could go down as one of the most successful NASA missions in history.
In recent years, it is the search for rocky extrasolar planets in their parent stars' habitable zones that has been the focus for astronomers. Thanks to advances in technology, exemplified by Kepler, that allow for the measurement of stars' brightness to almost unimaginable sensitivities, this can now be done as these Earth-sized planets were simply impossible to detect with the older Doppler Shift technology that was used to find the first extrasolar planets, all of which were Jupiter-sized giants.
To date, Kepler has found over 3,500 probable planets orbiting other stars. So far, less than 5%, have been confirmed to exist but mission scientists estimate that, in time, over 90% of these potential planets will be confirmed as real. The interesting trend in these findings: Earth-like planets are being found at ever-increasing frequency and that smaller (Neptune and smaller-sized) planets are more numerous than Jupiter-like worlds. While certainly not being the fingerprint of an alien civilization, Kepler's discoveries are interesting in that it is now known that very inviting, Earth-like planets, can exist throughout the reaches of space.
In the end, no matter what happens with the observatory itself, it will have a rich legacy of discovery that is sure to keep scientists busy for years to come.
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