Like a groggy traveler after a long , cold night , the European Space Agency 's comet-chasing Rosetta spacecraft woke up , warmed up and called home Monday before setting off on the final leg of its journey . Rosetta shook off 31 months of sleep , during which it traveled into the dark reaches of the solar system , and contacted its operators Monday evening . Cheers erupted in the ESA mission control center in Darmstadt , Germany , when a signal from Rosetta arrived shortly after 7 p.m. ( 1 p.m . ET ) . `` The spacecraft is there , it 's awake , and I think we are all overwhelmed , '' mission manager Gerhard Schwehm told reporters . Now , he said , controllers will have `` two busy years ahead of them '' as it approaches its target , Comet 67P/Churyumov-Gerasimenko , and follows it around the sun . There was only an hour window for the signal to reach Earth , putting scientists on pins and needles . `` The spacecraft decided to make us suffer after two and half year , '' Paolo Ferri , head of ESA Mission Operations told CNN . `` We came almost to the end of the window , we were very tense , '' he said . The unmanned probe was launched in 2004 and is now nearly 500 million miles ( 800 million kilometers ) from the Sun -- a distance that puts it just past the orbit of Jupiter . At that distance , the message it beamed back took 45 minutes to arrive . When the signal finally arrived there were cheers of relief . Wake up Rosetta : You have a date with a comet . If all goes well , Rosetta will rendezvous with the comet in August and fly with it for two years . Scientists now have to learn how to maneuver the craft around a comet . `` It 's flying in a very unusual environment for space flight with gas and dust and not much gravity to keep your obit stable , '' Ferri said . Rosetta is also supposed to send a small lander to the surface of the comet in November . The mission will give scientists unprecedented insight into the makeup and structure of these ancient residents of the solar system , ESA officials say . `` This is groundbreaking science , '' Rosetta project scientist Matt Taylor told ESA television . `` We 're looking at where we came from , the evolution of our own solar system . And comets are looked upon as kind of a time capsule back to the beginning of the solar system . '' Scientists believe comets , composed of rock and ice , may have brought water and maybe even the primitive building blocks of life to Earth . Rosetta carries 11 scientific instruments ; its lander has 10 more . ESA controllers ordered Rosetta to shut down most of its systems in June 2011 to save on power as it sailed through the darkest reaches of the solar system . The amount of sunlight reaching the solar-powered probe is only 4 % that on Earth , according to ESA . Follow @ CNNLightYears on Twitter for more space news .
ESA 's comet probe Rosetta shows up , sending a signal back to Earth . The spacecraft is nearly 500 million miles from the Sun , angling to rendezvous with a comet . Scientist must now learn how to maneuver the craft around the environment of the comet . Rosetta is set to meet up with the comet in August , observing it for two weeks .