The chase is over. The European Space Agency's Rosetta has become immortalised in space history as the first mission to land a spacecraft on a comet.
Just after 3am came news that Philae, the three-legged lander no bigger than a washing machine, had safely touched down on comet Churyumov-Gerasimenko. The most daring space mission since man landed on the moon had pulled off its signature manoeuvre without a hitch. Almost.
Cheers and applause erupted from ESA's control rooms in Darmstadt, Germany, as Rosetta's flight director Andrea Accomazzo announced the signals confirming Philae's touchdown had been received.
"We can't be happier than we are now," he said.
The landing was predicted to be particularly fraught because of the comet's rough surface, which is covered with boulders, crevasses and craters. Against all the odds, the 100-kilogram lander arrived safely within its target site.
The Philae lander manager, Stephan Ulamec, said: "Philae's sitting on the surface and talking to us. We are on the comet.
"We are extremely relieved to be safely on the surface of the comet, especially given the extra challenge of the comet's unusual shape and unexpectedly hazardous surface," said Dr Ulamec.
"In the next hours we'll learn exactly where and how we've landed, and we'll start getting as much science as we can from the surface of this fascinating world."
But flight engineers do know Philae's two harpoons, designed to anchor the lander to the comet's surface, did not fire. Dr Ulamec speculated that Philae may have touched down and then bounced slightly before touching down again.
Engineers expect to gain a more detailed picture of the landing when Philae re-establishes contact with Rosetta later on Thursday.
Rosetta was launched on 2 March 2004 and travelled 6.4 billion kilometres through the solar system before arriving at the comet in August.
During its decade-long journey, Rosetta has continued to push the boundaries of space engineering, from its three slingshot flybys of Earth and its two and a half year hibernation to Philae's completely automated descent and landing.
The director general of ESA, Jean-Jacques Dordain, said the biggest problem of success was that it looked easy, but the Rosetta mission was the result of experts from more than 20 countries working together for decades.
"This is a big step for civilisation," he said.
What now:
Now firmly anchored to Comet 67P, Philae's science instruments will begin taking samples and measuring the properties of the comet and its surface. Several instruments collected data during the descent.
As comets are some of the only original material left over from when the planets first formed, studying them will reveal insights about how the planets assembled and how Earth came to be covered in water. They may even unlock secrets on the origin of life.
Several of Philae's instruments are already collecting data.
- Six micro-cameras will take panoramic pictures of the surface (CIVA)
- One instrument will measure the electrical and mechanical properties of the surface (SESAME)
- A drill will take sub-surface samples from 22 centimetres and feed them to the on board laboratory (SD2)
- Another camera will take a close-up of the surface (ROLIS)
- Gas measurements will be taken (COSAC and PTOLEMY)
The lander's on-board batteries are only expected to last about 64 hours. Later, it will switch to solar power.
Touchdown! My new address: 67P!
#CometLanding — Philae Lander (@Philae2014)
November 12, 2014
I'm on the surface but my harpoons did not fire. My team is hard at work now trying to determine why.
#CometLanding — Philae Lander (@Philae2014)
November 12, 2014
It's me… landing on a comet & feeling good! MT
@ESA_Rosetta: I see you too!
#CometLanding
pic.twitter.com/DjU0J1Ey4H — Philae Lander (@Philae2014)
November 12, 2014
