|
 Rosetta, launched by the European Space Agency (ESA) in 2004, will
accompany comet 67P/Churyumov-Gerasimenko on its trip around the sun
and land a probe on it later this year in an unprecedented maneuver.
Scientists are now on a tight schedule to learn enough about the
comet using data from Rosetta to safely land the spacecraft's probe
on it in November.
"We know what the comet's shape is. But we haven't really measured
its gravity, we don't know yet where the center of mass is," Rosetta
Flight Director Andrea Accomazzo told Reuters ahead of the
rendezvous.
As it neared 67P/Churyumov-Gerasimenko this year, Rosetta took
pictures revealing that it is not shaped, as had been assumed, like
a rugby or American football, but rather comprises two segments
connected by a neck, giving it an asymmetrical shape that has been
likened to a duck.
Scientists hope data the probe gathers on the surface of the comet
will allow them to peek into a kind of astronomical time capsule
that has preserved for millions of years clues about what the world
looked like when our solar system was born.
It has taken Rosetta 10 years, five months and four days to reach
the comet, a roughly 3-by-5 km rock discovered in 1969. On its way,
the spacecraft circled the sun on a widening spiral course, swinging
past Earth and Mars to pick up speed and adjust its trajectory.
The mission performs several historical firsts, including the first
time a spacecraft orbits a comet rather than just whizzing past to
snap some fly-by pictures, and the first time a probe has landed on
a comet.
[to top of second column]
|
Because the trip is so long and took Rosetta so far from the sun's
solar rays, the spacecraft was put in a deep sleep for 31 months and
woken up earlier this year.
There is little flexibility in Rosetta's schedule this year. The
comet is still hurtling toward the inner Solar System at almost
55,000 km per hour, and the closer it gets to the sun the more
active it will become, emitting gases that can make it difficult to
predict the trajectory of Rosetta and its probe.
"We have a lot of time pressure to produce engineering models of a
world that we don't know yet," said Accomazzo, based at the ESA's
satellite operations in the German town of Darmstadt, south of
Frankfurt, who has been working on the Rosetta mission since 1997.
(Editing by Robin Pomeroy)
[© 2014 Thomson Reuters. All rights
reserved.] Copyright 2014 Reuters. All rights reserved. This material may not be published,
broadcast, rewritten or redistributed.
 |
