The European Space Agency’s comet-chasing Rosetta spacecraft woke up and called home Monday just before taking off on the last of its journey. The craft had spent the previous 31 months asleep while traveling out into the solar system. The ESA mission control center broke out into cheers in Darmstadt, Germany after receiving a signal from Rosetta. Scientists waited anxiously, with only an hour window for the signal to reach Earth. The unnamed probe was launched in 2004 and is now almost 500 million miles away from the sun, just past the orbit of Jupiter. With the probe being at this far of a distance, the message sent on Monday night took 45 minutes to reach to Earth.
