Europe’s Rosetta probe has arrived at a comet after a 10-year chase.
In a first for space history, the spacecraft was manoeuvred alongside a speeding body to begin mapping its surface in detail.
The spacecraft fired its thrusters for six and a half minutes to finally catch up with comet 67P/Churyumov-Gerasimenko.
“We’re at the comet!” said Sylvain Lodiot of the European Space Agency (Esa) operations centre in Germany.
“After 10 years, five months and four days travelling towards our destination, looping around the Sun five times and clocking up 6.4 billion km, we are delighted to announce finally ‘we are here’,” said Jean-Jacques Dordain, director general of Esa.
Launched on board an Ariane rocket in March 2004, Rosetta has taken a long route around our Solar System to catch up with comet 67P.
The comet is travelling at 55,000km per hour (34,175 mph). The spacecraft’s speed has been adjusted so that in relative terms it will be flying beside the comet at a slow walking pace of 1m/sec (2.2mph, 3.6kph).
At a distance of 550 million km from the Earth, messages are taking over 22 minutes to get to Rosetta.
The distances involved are so great that the complex final command sequence for Wednesday’s crucial thruster burn had to be issued on Monday night.
“This arrival phase in fact is the most complex and exotic trajectory that we have ever seen,” said Jean-Yves Le Gall, president of the French Space Agency CNES.
Rosetta will have to continue to fire its thrusters every few days to maintain a triangular orbit at 100km above the rotating rock.
The craft will then travel alongside the comet for the next 15 months, studying it with a range of instruments.
after moving Rosetta closer to 67P, mission controllers will attempt to put the Philae lander on the surface.
The lander will use harpoons to anchor itself and will carry out a series of experiments, including drilling into the material that makes up the comet.
The mission aims to add to knowledge of comets and their role in ferrying the building blocks of life around the early Solar System.
