Rosetta's comet chase is on.
Rosetta phones home!
Fresh out of an unprecedented power-saving sleep mode, Europe's comet-chasing Rosetta spacecraft awakened and phoned home Monday on the way to an enigmatic ball of rock and ice for a daring close-up inspection later this year.
Out of contact with Earth since June 2011, Rosetta is about to conclude a 10-year sojourn through space and pull alongside comet named Churyumov-Gerasimenko in August, when the European Space Agency probe will become the first mission to ever orbit a comet.
European Space Agency officials say Monday's wakeup launches Rosetta into a year of firsts: rendezvousing with a little-known comet beyond the orbit of Mars, maneuvering into a series of jagged, imprecise orbits, surviving blasts from dust and ice crystals, then ejecting a hitchhiking robot named Philae to latch onto the comet with harpoons and ice screws.
Such a tricky encounter, set to begin this summer, has never tried before.
"We have our comet-chaser back," said Alvaro Gimenez, ESA's director of science and robotic exploration. "With Rosetta, we will take comet exploration to a new level. This incredible mission continues our history of 'firsts' at comets, building on the technological and scientific achievements of our first deep space mission Giotto, which returned the first close-up images of a comet nucleus as it flew past Halley in 1986."
Rosetta's on-board timer was programmed to go off at 1000 GMT (5 a.m. EST) Monday, but it took nearly eight hours to receive a report on the spacecraft's condition. The probe roused itself from sleep, activated heaters and regained control of its orientation before aiming its high-power antenna toward Earth.
Admittedly nervous after waiting 31 months without any signals from the $1.7 billion mission, ground teams at ESA's control center in Darmstadt, Germany, were elated with the news.
Although Rosetta's signal made it to Earth within the expected window, the team had to wait a little longer than most officials expected. Large NASA-owned 70-meter (230-foot) antennas in California and Australia were trained on Rosetta's predicted location in the sky waiting on a peep from the probe 500 million miles away.
A video feed streamed from the Darmstadt control center finally showed a spike in the signal at 1818 GMT (1:18 p.m. EST).
"I think that's been the longest hour of my life," said Andrea Accomazzo, Rosetta's spacecraft operations manager.
"It's been a spectacular few moments of torture," said Martin Kessler, Rosetta's science operations manager.
The Rosetta control team, led by operations manager Andrea Accomazzo at center, celebrate at the European Space Operations Center in Darmstadt, Germany, after receiving the first signals from Rosetta after Monday's wakeup. Credit: ESA/J. Mai