Scientists breathed a sigh of relief today as a spaceship that had been in "deep space hibernation" for almost three years came back to life.
The Rosetta probe was launched in 2004 with the aim of planting a lander on the surface of a comet as it approaches the sun.
Since June 2011, the craft has been in an intentional state of shut-down while it completes the stage of its orbit that it furthest from the sun.
At 10am this morning, after 31 months asleep, an automatic "alarm clock" was activated to inform Rosetta that her solar panels were back within range of the sun's rays.
But owing to the fact that she was still 418 million miles (673m kilometres) from Earth, scientists had to wait another eight hours for a signal that she was indeed awake.
Her first words, communicated through a dedicated Twitter account, were:
Rosetta went on to repeat the words in more than 20 European languages.
Back at the European Space Station, the first hint of life came in the form of a little blip on a graph.
The news was greeted with much cheering and hugging by scientists in the mission control room, some of whom had devoted their life's work to the project.
My antennas started tingling a few hours ago with all the shouting and wonderful #wakeuprosetta messages. Thank you!
Rosetta is now around 5.6 million miles (9m kilometres) from its destination, the comet 67P/Churyumov-Gerasimenko, and closing on the object at half a mile a second.
One of Rosetta's first tasks after reaching the comet will be to search for a suitable landing site for the box-like Philae lander, which will drill samples from the ground for analysis.
Philae will also capture panoramic images of the view from the comet's surface with an on-board camera, just as the Mars Rover has done.
Scientists hope Rosetta will answer important questions about the origins of the Solar System and the way comets evolve and develop.