Just after 3am on Thursday came news that Philae, the three-legged lander no bigger than a washing machine, had touched down on comet Churyumov-Gerasimenko. The most daring space mission since man landed on the moon appeared to pull off its signature manoeuvre without a hitch.

Cheers and applause erupted from the European Space Agency'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 within its target site.

"Philae's sitting on the surface and talking to us. We are on the comet," said lander manager Stephan 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," he said.

But minutes after the landing confirmation, mission control learnt Philae's two harpoons, designed to anchor the lander to the comet's surface, had not fired.

Late on Thursday the lander was described as "stable" despite the harpoons failing to deploy.

Rosetta project scientist Dr Matt Taylor said the European Space Agency was receiving a good signal and receiving science data.

"Now we are busy analysing what it all means and really trying to find out where the lander actually is on the surface," he said.

Philae landed in a soft area on the 67P/Churyumov-Gerasimenko comet and dipped around 4 centimetres before bouncing back up when its harpoon failed to fire.

It went straight back up for two hours and drifted out into space before descending to the surface. It bounced again for a few minutes before settling in what Dr Taylor described as "three landings for the price of one".

"The descent was due on to a particular point on the surface of the comet. The bounce would have made it go up and then the comet's rotating underneath," the British scientist said.

"So we know, if we are looking at an image, that most likely the lander is somewhere on the right and now we are trying to refine that to really start focusing on the orbiter images to see where it is.

"In the next few hours we hope to be piecing the data we get on the lander to add this all together."

Rosetta was launched on  March 2, 2004 and travelled 6.4 billion kilometres through the solar system before arriving at the comet in August.

During its decade-long journey, Rosetta continued to push the boundaries of space engineering, completing three slingshot flybys of Earth, a two-and-a-half-year hibernation as well as Philae's completely automated descent and landing.

ESA  director general  Jean-Jacques Dordain said the biggest problem of success was that it looked easy, but the Rosetta mission was the result of decades of work from experts in more than 20 countries.

"This is a big step for civilisation," he said.

Since touchdown, Philae's science instruments have begun taking samples and measurements of the comet's surface properties. Several instruments collected data during the descent. During the next two days it is expected to complete its primary science mission, including drilling below the surface and taking panoramic images, until its batteries run out. Later, it will switch to solar power.

Because comets are some of the only original material left over from when the planets first formed, studying them will reveal insights about the way the planets assembled and how Earth came to be covered in water. They may even unlock secrets on the origin of life.

with agencies