Confirmation received of the first ever comet landing
Successful touchdown of the landing robot Philae marks climax of 10 year, 6.4 billion km journey
Esa confirms the harpoons designed to attach Philae to the comet did not fire, but its smaller screws appear to have dug into the surface
Philae was released at 08:35 GMT and took seven hours to reach comet 67P
Pictures have been received of the descent in progress - more are now eagerly awaited from the comet surface
Live video from the European Space Agency's operations centre in Darmstadt, Germany
What a great image - not real, of course...
The New York Times science desk tweeted:, external Imagine comet #67p was falling toward Manhattan rather than @Philae2014 falling toward it (for scale)
Image source, New York Timestweets, external: We all saw a photo flash very briefly on the webcast stream! Want photo! #CometLanding
The brief Esa TV broadcast ended "without a clear look" at the images from CIVA, she adds.
CIVA is a set of cameras on Philae that can analyse both visible and infra-red light.
The next burst of live video from Esa headquarters is expected soon, to announce the delivery of new images.
If you've just joined us: everything has gone according to plan today, except for a malfunction with the lander Philae's gas thruster.
This makes the landing trickier but not impossible.
The delivery manoeuvre, separation from the "mothership" Rosetta, re-establishment of radio contact, and switch-on of various components on Philae have all happened on schedule.
Image source, ESA/Rosetta/NAVCAMJacqui Grant: This is absolutely fantastic, got everything crossed that little Philae misses the cliff and lands safely. Thank you BBC for allowing us to be a part of this amazing day.
Jonathan Amos
Science correspondent, BBC News
Assuming Philae can avoid the cliffs, the boulders, the fissures and the steepest slopes, it has a good chance of getting down in a stable configuration. But how do we know it's down? The action of the feet and legs touching the surface is to move a central pole running up the middle of the robot's main housing.
This will generate a signal that activates the screws in the feet and the harpoons on Philae's underside. It should also have activated the small gas thruster on the roof of the housing, pushing the probe into the surface. But, as we heard earlier today, we're no long sure this will work. So for Philae to succeed at landing, a soft surface will be preferable - something like a "snowdrift".
We're not sure what the strength of the surface materials is, but, if Philae encounters a consistency like "cigarette ash" or "champagne snow" - as some scientists have speculated - there's every hope it will become embedded in the surface.
The confirming of touchdown will come from here at Esa's mission control in Darmstadt, but it will be the German space agency's lander control centre in Cologne that will determine whether Philae is stable on the surface. This could take a few minutes. The news - good or bad - will then be relayed to Darmstadt for the world to hear.
Image source, EsaMichael Willby: As one old enough to remember the grainy black and white TV from the Apollo project this endeavour deserves our greatest admiration for all those involved. If we, as fascinated observers, are on tenterhooks think how those who have given years of their lives feel. Good luck.
There is a new interview in the "key video" tab above: What is the comet's structure like?
Prof Mark McCaughrean speaks to BBC global science correspondent Rebecca Morelle.
He says the failure of the Philae lander's gas thruster, which delayed one of the decisions overnight, has "added another risk" to the already ambitious mission.
Tom Shaw: Our sixth form computing class is watching, completely gripped by the events unfolding. Amazing.
As a reminder: this is the target landing site, known as "Agilkia".
Not what you might call an easy spot to park... Read more about the choice here.
Image source, ESA/Rosetta/NAVCAM/MPS for OSIRIStweets, external: Taking bets now on how deep we'll sink when @Philae2014, external lands (that is, if it doesn't hit the cliff at the edge of the landing ellipse).
One of the researchers working on the mission, Dr Marina Galand, external from Imperial College of London, said that landing the spacecraft on the comet could be a precarious exercise:
"We don't know exactly what the surface is made of, we don't know if it's hard ice, and then the probe could bounce back; or it could be fluffy snow and it could sink. So in order to prevent the bounce-back, there are two harpoons which are going to be fired. There are mechanical screws which hopefully will lock it to the surface.
"The lander is as big as a washing machine, so hopefully that's big enough to prevent it from sinking. It could also topple. So a lot of challenges. I'm very anxious, it's very risky - but on the other hand if it goes through, it will really make history by being the first probe to ever touch down on a comet."
@japmfut tweets:, external Right now, someone is landing a robot on a comet 4 billion miles away at 40,000 mph. What the hell are you doing with your life? #Rosetta
tweets:, external Here are those @twitter stats shown in the broadcast, #cometlanding trending worldwide!
Image source, Esatweeted at 11:47, external: Not much will happen for the next hour. After that, some time in the subsequent hour we should see the CIVA photos. #CometLanding
Adrian Macey, Needham Market Middle School, Suffolk: My year 6s excited following bbc live updates, are coming back at lunch break to see if radio contact reestablished, and aim to follow when they get home! Thank you BBC!
tweets:, external @esa @ESA_Rosetta Following @Philae2014 progress with eager anticipation.Wish you all great success with landing later today! #CometLanding
@ldelaperrelle tweets:, external Congratulations to the scientists on the #CometLanding @ESA_Rosetta @Philae2014 awaiting landing of a craft on a comet - amazing!
tweets, external: While waiting for the latest announcements @chrislintott, external quizzes @mggtTaylor, external for #skyatnight on Sunday at 9pm BBC4
Pallab Ghosh
Science correspondent, BBC News
The signal from the Philae lander was a critical moment in the mission. It confirms that the probe will be able to send pictures and scientific data back from the comet should it land successfully in a few hours time. But that is far from certain. The landing site is strewn with boulders and there are large cracks in which the probe could fall into.
The task has been made harder by the fact that a thruster that should have pushed Philae, gently on to the comet is not working. But engineers are optimistic that two harpoons and ice screws on Philae will be enough to anchor it successfully.