A computer generated image shows Rosetta, the billion-dollar comet-chasing-spacecraft

Citizens of Planet Earth are being invited to make a "video shout-out" to wake up a deep-space probe, Rosetta, that has been in hibernation since June 2011.

The European Space Agency (ESA) is offering prizes for the best video clip of people shouting "Wake up, Rosetta!" to help end its scout's long sleep next month.

Launched back in March 2004, Rosetta is designed to rendezvous with Comet 67P/Churyumov-Gerasimenko next year at 673 million kilometres (420 million miles) from the Sun.

It will then send down a refrigerator-sized lander called Philae, which will hook onto the comet's surface and carry out scientific tests.

Scientists are fascinated by comets, which are believed to be primitive clusters of dust and ice dating back to the building of the Solar System, billions of years ago.

Rosetta, one of Europe's most ambitious and costliest missions, is programmed to move out of slumber mode at 1000 GMT on January 20. After warming up, it will hopefully contact Earth a few hours later, for the first time in 31 months.

The probe gets its name from the famous stone that led to the deciphering of Egyptian hieroglyphics almost 200 years ago.

The top 10 "wake up" videos will be blasted into the Universe with 20,000 watts of power by ESA's Deep Space network.

The best two will earn tickets to in Darmstadt, Germany, to watch Philae's touchdown in November.

Details and rules on www.facebook.com/RosettaMission .