The Kepler spaceship is in trouble again, and NASA scientists are diligently working to find creative fixes for a telescope flying three times further away from Earth than Venus.
NASA received a transmission on Thursday that Kepler space telescope had entered "emergency mode," according to a NASA statement. The spacecraft had switched to its maximum power setting 36 hours earlier, just as it readied for a readjustment to point towards the Milky Way galaxy center.
This transmission is not the first to send NASA scientists scrambling to find a fix during a Kepler mission. But emergency mode will force Kepler to burn quickly through its power supply, so mission control engineers for NASA's Deep Space Network in California have a tight deadline to save the $600 million spaceship.
One major challenge to fixing a spacecraft mid-mission is the remoteness of the work. No extra materials will become available to aid repair, and scientists can use only the models they have on the ground and the reports they receive. Fixing Kepler is especially difficult because its mission has taken it so far from Earth, even for a spaceship. At a distance of 75 million miles from Earth, even light-speed transmissions take 13 minutes to travel roundtrip from Kepler to its home base at NASA and back.
“You’re not watching it unfold in real time,” Dustin Putnam, a lead for Kepler, said in a NASA statement. “You’re watching it as it unfolded a few minutes ago, because of the time the data takes to get back from the spacecraft.”
NASA launched Kepler in March of 2009, and initially, the mission to find exoplanets was a complete success, Sarah Lewin wrote for Space.com. The telescope used the "transit method" – watching sun-like stars to see whether they briefly lose a fraction of their brightness, a sign that an orbiting planet passed in front of it – to detect over 1,000 new planets. This means Kepler has discovered over half the known exoplanets, a planet orbiting a star other than our sun.
The mission halted in 2012, however, when Kepler lost one of its four reaction wheels, which are essential to keep the telescope steady while it searches for the tiny blips that indicate a far-off planet, The Christian Science Monitor's Ben Thompson wrote. A year later, another wheel went out. Although it had been slated for only a four-year run, the data Kepler provided was too noisy for easy processing, and scientists needed more time to complete the mission than expected.
To save its cosmic investment, NASA decided to re-direct Kepler's mission. Engineers calculated the pressure the sun exerted on the tiny spaceship and discovered it could function as a "third wheel" that would hold the telescope steady for 80 days at a time if they placed it carefully enough. They renamed the mission K2 and re-initiated the interstellar search in May of 2014.
Kepler's K2 mission reached a milestone of success in early January, The Christian Science Monitor reported. NASA announced the spaceship had found 100 "alien planets," meaning planets at just the right distance from their star to hold possibilities for water – and life.
“Many of us believed that the spacecraft would be saved, but this was perhaps more blind faith than insight,” said Tom Barclay, senior research scientist for the Kepler program. “The Ball team devised an ingenious solution allowing the Kepler space telescope to shine again.”
Based on the creative solutions developed by NASA scientist in the past, there's hope that Kepler can resume its planetary hunt.