The Kepler space telescope is back in action after mysteriously shifting into emergency mode last week.
"Mission operations engineers have successfully recovered the Kepler spacecraft from Emergency Mode (EM)," said Charlie Sobeck, Kepler's mission manager at NASA's Ames Research Center.
"On Sunday morning, the spacecraft reached a stable state with the communication antenna pointed toward Earth, enabling telemetry and historical event data to be downloaded to the ground. The spacecraft is operating in its lowest fuel-burn mode."
The telescope is situated 75 million miles from Earth and is used to scan the galaxy for exoplanets circling distant stars. It finished its last mission on March 23 and was placed in a Point Rest State, which keeps the telescope's communications antenna pointed towards ground stations while using the least possible amount of fuel.
Last week, the telescope was supposed to be orientated to look at the center of the Milky Way as part of a mission which is looking for exoplanets and wandering planetary bodies near the heart of our galaxy. But NASA engineers performing a check found Kepler locked in EM after an unexplained fault.
Engineers at the Ames Research Center in California's Silicon Valley, Ball Aerospace, and the Laboratory for Atmospheric and Space Physics at the University of Colorado are now going over the telescope's systems and analyzing how much fuel is left in the distant instrument.
"It was the quick response and determination of the engineers throughout the weekend that led to the recovery," Sobeck said. "We are deeply appreciative of their efforts, and for the outpouring of support from the mission's fans and followers from around the world."
Frankly, it's a miracle the telescope has lasted this long. The telescope maintains its orientation using four reaction wheels that rotate to provide stable aiming of the scope's 95-megapixel camera, and in 2012 one of the wheels stopped working.
NASA wasn't too worried, since the telescope had been designed to work with three. But in 2013 a second wheel failed, causing the telescope to lose orientation. After months of careful calculations, NASA worked out a way to stabilize the instrument by using the pressure of solar wind against the telescope's solar panels counterbalanced by the two remaining wheels.
The telescope has been in operation since December 2009 and was only supposed to last for three and a half years. NASA engineers are experts at interesting hacks to keep hardware going, but these latest problems do indicate the telescope might be nearing the end of its useful life. ®