After creating a minor panic when it went into Emergency Mode two weeks ago, the Kepler Space Telescope is back to doing science. As of 1:30am AEST (11:30am ET) today, it's continuing the search for planets beyond our solar system. Kepler is the most productive exoplanet-hunting machine humans have ever built, but it also has a history of breaking down. In 2012, one of the spacecraft's four stabilising reaction wheels snapped. At first, this didn't seem to be a problem, but when a second wheel broke in 2013, Kepler started spinning out of control. That ended the spacecraft's primary mission, of searching for planetary transit events in a fixed, distant region of space.
But a year later, astronomers figured out a way to repurpose the janky telescope to do all sorts of other science, from planet hunting to astrophysics. The K2 mission was born.
K2 was about to commence its ninth 80-day observational campaign when, on April 8, NASA discovered Kepler had gone into Emergency Mode. Nobody could explain what had happened, but miraculously, NASA managed to regain control of the spacecraft just a few days later. Now the effort to detect exoplanets via gravitational microlensing officially underway, just a few days behind schedule.
NASA's still trying to figure out why Kepler bugged out. For now, let's just be happy the telescope is back up and running — it's pretty rare for a spacecraft to get this many second lives.