Rosetta comet landing: as it happened - Telegraph.co.uk

It's complicated to land on a comet. It's also complicated to understand what has happened during he landing. What we know that we touched down and we landed on the comet. We had a very clear signal and we also recieved data from the lander. That is the very good news

The not so good news is that the anchoring harpoons did not fire. So the lander is not anchored to the surface. Did we just land in a soft-sand box and everything is fine? Or is there something else happening. We still do not fully understand what has happened.

Some of the data indicated that the lander may have lifted off again. It touched down and was rebouncing. We saw data on the solar generator which could be interpretre that the lander lifeted off and started to turn itself. About two hours later this information of turning stopped. So maybe today, we didn't just land, we landed twice.

Dr Stephan Ulamec, Philae Lander Manager at the DLR German Aerospace Center.

It's a great day. Not only for ESA but for the world. We landed and Philae survived the landing. We have landed at the right place. It's also the right comet, don't worry. And we have got the radio link which is very important and we have the power on board.

The data has to be analysed. It is only less than three hours we are on the comet. So you have to give some time to analyse the data. I wish that we are careful because we are just at the beginning.

Jean-Jacques Dordain, ESA's Director General

18.51 We are scheduled to get an update on how Philae is doing at 7pm. But it appears there is a problem with the harpoons on the lander which could jeopardise the mission.

18.00 The first pictures are starting to drop showing Philae's view as it floated towards comet 67P/Churyumov-Gerasimenko. The landing site, which has been named Agilkia, is on the smaller of the comet's two lobes.

^{Philae took this pictures when it was just 3km from the surface of 67P/Churyumov-Gerasimenko}

17.00 Oh dear! It seems the anchors did not shoot properly so the scientists have no way of knowing at the moment if the probe is secured on the comet. The Philae team is considering whether to fire them again. The problem with doing that is that gravity is very weak and the motion could shoot the probe back into space. Another tense wait.

16.55 First pictures will be back from comet 67P/Churyumov-Gerasimenko within the hour

16.50 So what happens now? Philae only has battery power to last 2.5 days so it must get its main scientific observations out off the way quickly. After that it must rely on solar power but if the comet becomes more active the ice and dust clouds thrown up could cover the solar panels bring the project to a halt.

The probe will take a full panoramic view of the landing site, including a section in 3D. It will also start drilling into the comet surface. It's drill bit is nine inches long so it should be able to get some good deep samples. The lander will also measure the electrical and mechanical characteristics of the surface. In addition, low-frequency radio signals will be beamed between Philae and Rosetta through the nucleus to probe the internal structure.

If the solar panels work, Philae will continue monitoring the comet until March 2015.

16.24 Everyone pretty excited over in Germany. Lots of much-desrved handshaking and back-slapping ensuring. And it is an astonishing success. Think about it. When Rosetta was first conceived hardly anyone had mobile phones, Margaret Thatcher was in power and the Channel tunnel was eight years away from completion.

ESA and its Rosetta mission partners achieved something extraordinary today

Our ambitious Rosetta mission has secured another place in the history books: not only is it the first to rendezvous with and orbit a comet, but it is now also the first to deliver a probe to a comet's surface.

Jean-Jacques Dordain, ESA's Director General

After more than 10 years travelling through space, we're now making the best ever scientific analysis of one of the oldest remnants of our Solar System.

Decades of preparation have paved the way for today's success, ensuring that Rosetta continues to be a game-changer in cometary science and space exploration.

Dr Alvaro Giménez, ESA's Director of Science and Robotic Exploration.

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

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.

Dr Stephan Ulamec, Philae Lander Manager at the DLR German Aerospace Center.

16.03 Wow! It's done it. Philae is down and safely attached to the comet. And at exactly the time they predicted, which if you think about it, is totally astonishing.

We are on the comet! We are there and Philae is talking to us. Harpoons have been fired and rewound. We are sitting on the surface.

Dr Stephan Ulamec, Philae Lander Manager

Stefan Ulrech

15.55 We're just minutes away from confirmation that Philae has landed safely - however the live feed from Germany has gone down. Which is alarming. If they can't get pictures out from Darmstadt, God know's how they'll mange to get them from somewhere between Jupiter and Mars. The tension mounts...

15.30 Philae should be landing around about now. But there is a 28 minute delay in getting a signal back to Earth. We should know if the probe has been successful within the next hour. Remember, its thrusters are no longer working and there is a real fear the lander could simply bounce off the comet and back into space. So it's nail-biting stuff.

Earlier

15.20

Not content with spreading fear and widespread panic on the streets of London, the European Space Agency has now destroyed a large chunk of Paris with its comet comparison graphic. Fortunately the Left Bank, the Louvre and Arc de Triomphe remain unscathed. Dieu merci.

^{Zut alors! A comet has destroyed Paris}

15.00

Rosetta waves goodbye to Phillae as it descends on to the surface of comet 67P/Churyumov-Gerasimenko.

The lander separated from the orbiter at 9:03am and is expected to touch down on Comet 67P/Churyumov–Gerasimenko seven hours later. Confirmation of a successful touchdown is expected within an hour window from 16:02.

^{The Philae probe, picture floating down to the comet}

14.25

The first picture of Philae leaving Rosetta has finally reached Earth.

^{The first image taken by Philae shows Rosetta disappearing into the background}

14.00

It's been a fairly intense day for the Rosetta team at the European Space Agency. They have compiled a video of their highlights so far.

13.40

Professor Tom Marsh, of the University of Warwick’s Astronomy and Astrophysics group, has provided some more details about the danger of Philae bouncing off the comet. It really is a worry.

The lander is equipped with two harpoons that will be fired into the comet to anchor it. The hope is that the comet's surface is not bouncy. The lander comes in at about 1 metre per second, but it only needs 0.5 metres per second to escape the comet completely, and even a little vertical motion in such low gravity could lead to a significant "bounce".

So the loss of the donwards thruster certainly heightens the risk. A problem with a bounce is that you might also pick up some rotation; combine that with a jump away from the surface and then there is a worry about the angle at which it would come down after the bounce, so this is really something to be avoided.

The lander's legs are designed to try to absorb the impact, so with any luck the loss of the thruster won't be critical. By the way 1 metre per second is a pretty gentle landing -- you get the same speed on Earth by jumping off a 2 inch high step!

13.25

Honestly, ducks in space! They are like buses. Just weeks after it emerged that comet 67P/Churyumov-Gerasimenko looks like a rubber duck, now students at the University of York’s Astronomy Society are preparing to launch a rubber duck into the stratosphere.

Astroduck will aim to acquire scientific data such as altitude, temperature and air pressure as well as valuable footage to record the flight from launch to landing.

Here Adam Shore describes the project.

13.15

If anyone hasn't yet seen the utterly barking film that the European Space Agency made to illustrate the importance of the Rosetta mission it's below. Brace youselves.

13.00

So Philae is now more than halfway through its journey down to comet 67P/Churyumov-Gerasimenko. The landing site which has been chosen was recently named 'Agilkia', after the island on the Nile river in the south of Egypt where the Temple of Isis, previously on Philae island, is now hosted.

The temple was moved, along with many other magnificent monuments from the Nubian archaeological area, as part of the international campaign launched by UNESCO between 1960 and 1980 to rescue them from the rising waters of the Nile.

Apparently there has been some argument about how to pronouce 'Agilkia' - so mission control in Darmstadt, Germany, have produced an audio file. They really think of everything this lot.

12.15

Aaaaaaargh. Run for you lives. Huge comet spotted closing in on London. Oh, wait. Hang on, it's just a helpful graphic provided by the European Space Agency to show the size of comet 67P/Churyumov-Gerasimenko. As you were.

^{Credit: The European Space Agency}

11.56

Now that Rosetta and Philae are back in touch they are having a touching interstellar conversation via Twitter.

11.40

Twitter is getting very excited about Dr Matt Taylor's Rosetta leg tattoo.

11.10

Good news! Rosetta has successfully turned around and made contact with Philae. We should be getting the first pictures of the separation soon.

10.50

While Rosetta was orbiting 67P/Churyumov-Gerasimenko it took some amazing images of what the surface of the comet looks like. The rocky landscape is a stark reminder of just how tricky it will be to land a probe, especially now that the thrusters have stopped working.

10.20

The Open University has done a rather lovely video answering the five most commonly asked questions about the Rosetta mission. Well worth a watch.

We want to go to a comet because it's there. It's an object in our astronomical backyard and we want to know what it looks like and what it's made of.

Prof Ian Wright, Professor of Planetary Sciences at The Open University

09.55

So something you may not be aware of is that comet 67P/Churyumov-Gerasimenko is 'singing' in space. I say singing, it's actually making dolphin-like clicking noises, which increase in pitch. It also smells of rotten eggs. It would be a terrible dinner guest.

9.40

If you want to see what they are up to at Mission Control in Darmstadt, Germany you can watch them here. It's kind of like Big Brother, but with intelligent people and less nudity. The man in the blue lanyard has been starting at his screen for some time. He looks tense. Homes under The Hammer will do that to you.

An exitement of scientists (which is the correct collective noun)

9.30

This image taken by Rosetta this week shows how inhospitable the surface of comet 67P/Churyumov-Gerasimenko really is. Although comets are percieved to be dusty balls of ice, the surface is actually black like coal.

The gravity on the comet is tiny -- around 10,000 times less than the gravity on Earth -- so there is significant risk of bouncing off the comet

The lander is equipped with two harpoons that will be fired into the comet to anchor it. It is a very difficult and ambitious task, but if it comes off we will have a close-up view of a survivor from the earliest times of the Solar System, 4.5 billion years ago.

Prof Tom Marsh, of the University of Warwick’s Astronomy and Astrophysics group

9.03

Well they've only gone and done it! Separation has been confirmed. Now there is a nerve-shredding seven hour wait to see if it will land in the correct spot. We should get the first pictures of the detachment in a couple of hours when Rosetta has manouvred back into position and turned around so it's antenna can point back at Philae.

Philae2014 is gone - it's on its path down to the comet Flight Director Andrea Accomazzo

8.40

Rosetta is boldly going where nothing has gone before. Needless to say William Shatner is very excited, and has sent this video message:

8.35

The probe should now have been released. Despite problems, the Rosetta team decided to go ahead with the mission late last night.

The cold gas thruster on top of the lander does not appear to be working so we will have to rely fully on the harpoons at touchdown,” Stephan Ulamec, Philae Lander Manager at the DLR German Aerospace Center.

We’ll need some luck not to land on a boulder or a steep slope.There were various problems with the preparation activities overnight but we have decided to ‘go’.

Rosetta is lined up for separation Paolo Ferri, ESA’s head of mission operations.

It will take the radio signals from the transmitter on Rosetta 28 minutes and 20 seconds to reach Earth and be transferred to the Rosetta Mission Control Centre at ESA’s Space Operations Centre in Darmstadt, Germany. We should have confirmation at 9.03am.

8.00

Morning everyone. Sarah here. It's Rosetta day! Today the European Space Agency will make history (hopefully) by making a soft landing on a comet. It's never been done before. It's never been attempted before. Will it work? Probably. This mission has been in planning since the 1970s...seriously. Although they picked a different comet back then.

Don't forget Rosetta was launched in 2004, the year of the Boscastle floods, the inquest of Princess Diana and the Athens Olympics. Tony Blair was still in power for goodness' sake and the Iraq inquiry just a twinkle in Jack Straw's eye.

So it's been on quite a remarkable journey, travelling four billion miles through the solar system. It's currently between Mars and Jupiter.

If you have any questions or comment, please drop me an email at sarah.knapton@telegraph.co.uk or Tweet me at @sarahknapton

Here is what to expect over the coming hours.

• Philae separates from Rosetta - 08:35

• Confirmation signal at Earth of separation - 09:03

• Rosetta's post-delivery manoeuvre - 09:15

• Radio connection established - 10:30

• First data from descending Philae after 12:00

• Landing of Philae on 67P - likely after 15:30

• Confirmation signal at Earth - around 16:00