ABC News' Gina Sunseri reports:

How to catch a comet: First, set your alarm clock to wake up after a two-and-a-half year nap, then reboot your computer and check your odometer. You are now 500 million miles from where you started.

Rosetta is the European Space Agency's daring mission to catch up to comet 67P Churyumov-Gerasimenko after 10 years of hurtling through space (including the two-and-a-half year nap) to rendezvous with a comet speeding through space at 24,600 mph. Scientists put Rosetta into a planned hibernation 957 days ago to save resources so the spacecraft-probe would have enough power to complete its mission, leaving just a computer and a few heaters to keep it warm.

Rosetta @ESA_Rosetta has been auto-tweeting "still sleeping" for its 5,000 followers for the past two-and-a-half years.

In order to wake up the dormant satellite, ESA's Mission Control sent a very special wake-up song to Rosetta .

Jet Propulsion Laboratory scientist Claudia Alexander explained to ABC News what the satellite does following the signal: "When Rosetta wakes up, it will take a look around, we will be recommissioning the spacecraft, which is like rebooting your computer. It takes a while to spin and come up to speed again, weeks actually, while we are double-checking each instrument."

Rosetta launched March 4, 2004, using the gravitational pull of Earth and Mars as a slingshot to get into the proper comet-chasing orbit.

When it gets close in June, it will prepare to launch a probe named Philae to land on the comet, where it will drill into the icy surface and send back unprecedented data and photos.

Rosetta will release the impact probe Philae on July 3 but we won't know until July 4 when NASA's JPL will confirm impact and send back the first images from the probe if it is successful.

This is the first time any space-faring nation will land on a comet, and Alexander said she is excited about what we will learn. "To hang out in the neighborhood of a comet as it orbits will change what we know about comets," she said.

(C.CARREAU/AFP/Getty Images)