There was much cheering and back-slapping at the European Space Agency after a three-year bet paid off.
Watch the moment on the video below (from one minute and 30 seconds in):
This small green blip in the graphs below was the sign that scientists at the European Space Agency were waiting for to show that the Rosetta spaceship had awoken from its deep slumber:
The European Space Agency (ESA) has said it will take at least an hour-and-a-half to get a health report from the Rosetta spacecraft:
With one-way signal time of 45mins, it will take at least 90mins to get health report from @esa_rosetta - for now basic radio signal only
The European Space Agency says it has received a signal from its Rosetta spacecraft after a three-year sleep:
The European Space Agency (ESA) has said it expects to make contact with its comet-chasing Rosetta probe "any minute now".
'Any minute now we expect the signal from #Rosetta' - ESA Operatiosn Manager Andrea Accomazzo
This video from the European Space Agency shows a simulation of how the Rosetta spacecraft will wake up the "deep-sleep hibernation" it has been in since June 2011.
Rosetta's internal alarm clock will wake it up at 10:00 GMT so that it can resume its mission to rendezvous with Comet 67P/Churyumov-Gerasimenko.
The European Space Agency's comet-chasing Rosetta probe will be woken up from its "deep space hibernation" today.
The spacecraft will be brought back to life after two and a half years at 10am GMT to resume its mission towards Comet 67P/Churyumov-Gerasimenk.
But as its systems will take hours to power up and the signal has to travel more than 500 million miles back to Earth, the first signal from the spacecraft is not expected before 17:30 GMT.