Rosetta, which was launched by the European Space Agency (ESA) in
2004, is due to rendezvous with comet 67P/Churyumov-Gerasimenko and
land a probe on it this year in an unprecedented maneuver.
Scientists hope data the probe gathers will allow them to peek into
a kind of astronomical time capsule that has preserved for millions
of years clues as to what the world looked like when our solar
system was born.
"Since comets are so primitive, they can give scientists a chance to
understand how the solar system formed, where it came from," Rosetta
spacecraft operations manager Andrea Accomazzo told Reuters ahead of
the wake-up call.
On its way to the comet, a roughly 3 by 5 km-large rock discovered
in 1969, Rosetta has been circling the sun on a widening spiral
course, swinging past Earth and Mars to pick up speed and adjust its
The mission will perform several historical firsts, including the
first time a spacecraft orbits a comet rather than just whizzing by
it to snap some fly-by pictures, and the first time a probe has
landed on a comet's nucleus.
Rosetta is also the first mission to venture beyond the main
asteroid belt relying solely on solar cells for power generation,
which is also why it had to be put into a deep sleep for 957 days.
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"It has been so far away from the sun that the solar rays were not
able to generate enough energy to safely operate the spacecraft,"
said Accomazzo, who has been working on the Rosetta mission since
Accomazzo is based at the ESA's satellite operations in the German
town of Darmstadt, south of Frankfurt.
Having neared the sun again as it tracks the comet on its elliptical
orbit around the sun, Rosetta was gently awakened by its internal
alarm clock at 1000 GMT on Monday. It then warmed up its systems and
transmitted a sign of life — a radio signal — to its creators on
Once it is fully up and running, it will start to approach the
comet. By August, it should catch up with it and land its probe on
it in November.
Until the end of 2015, the probe will gather data on the comet's
surface and examine how it changes as its nears the sun.
(Additional reporting by Annika Breidthardt;
editing by Gareth Jones
and Pravin Char)
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