Some 36 hours ago, when NASA engineers contacted the agency’s planet-hunting spacecraft K2 as part of a scheduled task, they discovered that it had slipped into emergency mode (EM). The cause for this remains unknown. According to a press release from the agency, EM is the “lowest operational mode and is fuel-intensive”. It also gives NASA’s Deep Space Network, its array of ground-based communication systems, “priority access” to K2 to help it get back to normal.
When K2 was last contacted on April 4, NASA said it was operating as expected and nothing seemed off. Engineers were preparing to reorient the spacecraft, which trails Earth by about 151 million km in its orbit around the Sun, to point toward the centre of the Milky Way ahead of its planned microlensing observations campaign. This campaign plans to have K2 detect exoplanets closer to the galaxy’s nucleus by studying their gravitational effects on their host stars’ starlight, a technique suited for making observations across large distances. The change in the orientation of K2 is necessary because it allows engineers on Earth to see what K2 is looking at. This isn’t currently the case.
K2 was originally called Kepler until two components responsible for stabilising the craft failed in 2013. Then, it was repurposed to look only for potentially habitable exoplanets orbiting red dwarfs, a kind of dimmer, very-slowly evolving star thought to live for trillions of years. Between its launch in 2009 and the completion of its primary mission in 2012, the spacecraft spotted more than 5,000 exoplanet candidates; astronomers are still sifting through its data validating each detection. The tally of confirmed candidates crossed 1,000 as of 2015.