Comet-chasing Rosetta spacecraft to wake up from slumber in 100 days time

European Space Agency's comet-chasing mission Rosetta is going to wake up in 100 days' time from deep-space slumber to reach the destination it has been cruising towards for a decade.

By studying the nature of a comet close up with an orbiter and lander, Rosetta will show us more about the role of comets in the evolution of the Solar System.

Rosetta was launched on 2 March 2004, and through a complex series of flybys - three times past Earth and once past Mars - set course to its destination: comet 67P/Churyumov-Gerasimenko.

In July 2011 Rosetta was put into deep-space hibernation for the coldest, most distant leg of the journey as it travelled some 800 million kilometres from the Sun, close to the orbit of Jupiter.

The spacecraft was oriented so that its solar wings faced the Sun to receive as much sunlight as possible, and it was placed into a slow spin to maintain stability.

Now, as both the comet and the spacecraft are on the return journey back into the inner Solar System, the Rosetta team is preparing for the spacecraft to wake up.

Once it wakes up, Rosetta will first warm up its navigation instruments and then it must stop spinning to point its main antenna at Earth, to let the ground team know it is still alive.

After wake-up, Rosetta will still be about 9 million km from the comet. As it moves closer, the 11 instruments on the orbiter and 10 on the lander will be turned on and checked.

In early May, Rosetta will be 2 million km from its target, and towards the end of May it will execute a major manoeuvre to line up for rendezvous with the comet in August.