NASA's Mars Curiosity rover tweeted song lyrics by English rock band Whitesnake as it got back to work after its first period of "sick leave" in three years. A software glitch on the trundling mobile science laboratory forced it to shut down and enter safe mode over the 4 July holiday weekend. But after being brought out of safe mode on Saturday, it re-entered full operations on Monday night.

After its initial breakdown, a tweet posted on the rover's Twitter account said: "No sick days since 2013, and I go into precautionary safe mode over a holiday weekend? Shaking my head." After it was back up and running an update was posted saying: "Here I go again on my own. Down the only road I've ever known. Out of safe mode-back to work." In an update NASA officials wrote: "The most likely cause of entry into safe mode has been determined to be a software mismatch in one mode of how image data are transferred on board. "Science activity planning for the rover is avoiding use of that mode, which involves writing images from some cameras' memories into files on the rover's main computer. "Alternate means are available for handling and transmitting all image data."

The main goal of Curiosity's $2.5bn mission is to determine whether the Red Planet is capable of supporting microbial life.
So far, Curiosity has found that the planet's Gale Crater once hosted a system of lakes and streams, which suggests the area was habitable billions of years ago. For the past two years Curiosity has been exploring the hills around the three-mile-high Mount Sharp, which rises from the crater's centre. It is taking rock samples and analysing them to look for clues for when Mars shifted from a warm and wet world to the cold dry place it is now. Its mission was recently extended until at least October 2018.