European robot probe Philae has made the first, historic landing on a comet, after descending from its mothership.
The landing on Comet 67P/Churyumov-Gerasimenko was confirmed at about 1605 GMT.
There were cheers and hugs at the control room in Darmstadt, Germany, after the signal was confirmed.It was designed to shine a light on some of the mysteries of these icy relics from the formation of the Solar System.
The landing caps a 6.4 billion-kilometre journey that was begun a decade ago.
The lander sank about 4cm into the surface, suggesting a relatively soft surface.
But there remains some lack of clarity over whether the harpoons designed to fasten the spacecraft to the ball of ice and dust fired as intended.
“This is a big step for human civilisation,” said Jean-Jacques Dordain, the director-general of the European Space Agency (Esa).
Shortly after the touchdown was confirmed, Stephan Ulamec, the mission’s lander chief, said: “Philae is talking to us… we are on the comet.”
The first pictures from the surface have already reached Earth and are being processed in preparation for release.
Astronaut Chris Hadfield, famous for performing David Bowie’s Space Oddity on the space station, said of the comet: “Now we’re close enough to lick it, and see what it’s really made of.”
Prof Monica Grady of the Open University, who has worked on the project from its earliest days, was at mission control in Darmstadt and was jumping for joy when the news came through.
She told BBC News: “I can’t believe it, it’s fantastic, we’ve landed – we’ve waited so long for this.”
Scientists initially said Philae’s harpoons did not fire as intended, but BBC science correspondent Jonathan Amos said this remained unclear.
If they did not deploy, then scientists will take a decision on whether to re-fire them.
However, sources said that screws in the feet that are also designed to anchor the robot into the soil did work.
Earlier, a thruster system designed to push the robot down into the surface of the comet failed.
Part of the difficulty is the very low gravity on the 4km-wide ice mountain.
Philae needs to be wary of simply bouncing back into space.
The nature and strength of the surface materials on the surface are unknown.
Philae could have alighted upon terrain whose constitution is anything between rock hard and puff-powder soft.
Controllers in Darmstadt have already received pictures from the surface of the comet, but are getting intermittent drop-out in the lander’s signal.
Paolo Ferri, head of operations at Esa, told BBC News: “We need to stabilise this situation over the next three hours.”
If all continues to proceed well, Philae should take pictures of the comet’s landscape and to analyse its chemical composition.
They are hoping its surface materials will hold fresh insights into the origins of our Solar System more than 4.5 billion years ago.
One theory holds that comets were responsible for delivering water to the planets. Another idea is that they could have “seeded” the Earth with the chemistry needed to help kick-start life. – BBC News
