Two and a half years is a long time to sleep, even for a machine. That’s how long Rosetta has slumbered in its decade-long journey towards the comet where it will land. But in the dead of the night, at 2am PST tomorrow morning, Rosetta will awaken. Rosetta is many millions of miles away from Earth by now, well on its way towards the Churyumov-Gerasimenko comet, where it’ll land in May of this year.
At 10:00 GMT on Monday, the most important alarm clock in the Solar System will wake up ESA’s sleeping Rosetta spacecraft. Rosetta is chasing comet 67P/Churyumov–Gerasimenko and, since its launch in 2004, has made three flybys of Earth and one of Mars to build up enough speed and get on a trajectory towards the comet. It has also encountered asteroids Steins and Lutetia along the way. Operating on solar energy alone, the spacecraft was placed into a deep space slumber in mid-2011 as it cruised far from the Sun and out towards the orbit of Jupiter. To prepare for its long sleep, Rosetta was oriented so that its solar arrays faced the Sun and put into a once per minute spin for stability.