On Monday morning 20th January 2014 at 11:00am Central European Time (10:00am GMT) a snoozing spacecraft will be woken up nearly 1 Billion kilometres from Earth. It’s needed a long sleep, because it will have a lot of (literally) ground-breaking work to do.

It’s an interesting alarm call. ESA would have to send the wake-up call some 45 minutes in advance – it would take that long for the signal, traveling at the speed of light, to reach Rosetta from Earth! But it’s automated and here’s an excellent ESA explanation of the process (many thanks to Emily Baldwin – @AstroEmz on Twitter) of The Most Important Alarm Clock in the Solar System.

This mission is truly amazing – to get a spacecraft (Rosetta) to coincide and then fly with a comet 800 million kilometers from Earth, and hurtling towards the Sun. But not only that, to then deposit the Philae landing craft onto the comet itself to dig into the makings of this 4.5 billion year old fragment of the formation of the Solar System itself!
This can only be described as the biggest scientific and technological encounter in history and is the result of over a decade of planning and work by the European Space Agency (ESA), DLR, CNES, NASA, and many scientists, astronomers, universities and industry.

To put 800 million kilometres into perspective, it’s over five times the distance between the Earth and the Sun – Deep Space!