In this photo provided by the European Space Agency on Monday, Jan. 20, 2014, technicians celebrate after receiving the Rosetta wake up signal in the control room of ESA in Darmstadt, Germany.BERLIN – Waking up after almost three years of hibernation, a comet-chasing spacecraft sent its first signal back to Earth on Monday, prompting cheers from scientists who hope to use it to land the first space lander onto a comet.
The European Space Agency received the all-clear message from its Rosetta spacecraft at 7:18 p.m. (1818 GMT; 1:18 p.m. EST) – a message that had to travel some 500 million miles.
In keeping with the agency’s effort to turn the tense wait for a signal into a social media event, the probe triggered a series of “Hello World!” tweets in different languages.
Dormant systems on the unmanned spacecraft were switched back on in preparation for the final stage of its decade-long mission to rendezvous with the comet named 67P/Churyumov-Gerasimenko. Systems had been powered down in 2011 to conserve energy, leaving scientists in the dark about the probe’s fate until now.
Because of the time it took Rosetta to wake up, and the long distance between the spacecraft and Earth, the earliest possible hour for a signal to arrive was 6:30 p.m.