Rosetta mission: Esa weighs options for moving Philae lander – as it happened

Some of Philae’s experiments began shortly after landing, and Esa confirmed today that they’ve activated MUPUS (multi-purpose sensors for surface and subsurface science), a set of devices that will measure the density, thermal and mechanical qualities of the comet’s surface.

They’ve also activated CONSERT (comet nucleus sounding experiment by radiowave transmission), a sophisticated probe that sees right through the comet by way of radio waves. CONSERT links up with Rosetta, and is also being used to help triangulate Philae’s position, which we still don’t know with much precision.

One of the most important experiments, Ptolemy (after the ancient astronomer who also pioneered ideas about optics), may have to wait until batteries are almost dead, because it requires Philae to use its drill – which could shift the whole lander from its uncertain position.

Ptolemy is “an evolved gas analyzer”, and could help determine just what’s on comets and whether they could have seeded the Earth with organic compounds often called the “building blocks of life”.

Systems engineer Bobak Ferdowsi, he of the Nasa Mars mission mohawk, gives some perspective to yesterday’s accomplishment.

If you’re coming only recently to the Rosetta mission and want a quick recap on how Philae’s landing went, the lander’s challenges and the answers Esa is looking for on a ball of ice, rock and gas hurtling around the sun, take a look at a piece filed earlier today.

As Dr Geraint Morgan explained to Open University, “we will sniff the comet no matter what happens” – meaning that the probe will still examine molecules drifting up from the surface.

Many of the experiments are preprogrammed, and the Philae mission could help determine whether comets brought water to Earth, and whether they seeded our planet with chemical compounds (“organics”) that are the building blocks of life. Comets are ancient remnants of the solar system’s earliest moments, and 60 hours of data could provide a glimpse into what happened as the planets formed (or before they formed).

You can read the full piece here.

This Esa tweet from earlier in the day shows the site of the original landing (the purple) compared with the range where Philae is expected to be now (the blue diamond).

Nasa imaging specialist Doug Ellison takes a stab at visualizing how Philae stands on the comet.

We interrupt this record of a historic achievement in science with news theories of conspiracy surrounding the Philae landing, as compiled by my colleague Hannah Ellis-Petersen.

“Comet 67P is NOT a comet,” the UFO site letter continues. “Some 20 years ago Nasa began detecting radio bursts from an unknown origin out in space. It would later be known that these had likely come from the direction of the now named comet 67P. It does show signs on its outside of machine like parts and unnatural terrain.”

ESA’s confirmation that the comet had been emitting a “mystery song” has fuelled theories that it is in fact an alien ship and the warbling is an extra-terrestrial attempt at communication.

That “song” actually comprises oscillations in the magnetic field around the comet, audible to our ears only because Esa sped up the data 10,000 times its rate. You can read more from the creative minds of amateur investigators here, and learn more about the whistling here.

Earlier today Dr Bibring was asked about the surface of the comet and whether Esa can tell what sort of material makes up the area where Philae landed and now perches precariously.

The reporter asks whether the surface is low density fluffy stuff, as Esa sugested earlier. Bibring reminds him that we don’t know much at all about the comet yet:

“[The area near Philae] has some resonance in our head that it’s a cliff, but we don’t think it’s that sort of cliff because the material is very low density anywhere. The density is less than 0.5 … So the idea of having a very porous material at the top came from that [and from] from the very first images [of the comet] … We’re not saying that that’s not still the case, that might still be the case. We have not demonstrated that we don’t have a crust, we have not demonstrated that we have a crust.

“Are you satisfied? I’m very happy if you’re not satisfied.”

His colleague explains a bit more: “The rebound of the lander is an indication of a higher strength material, and that was a surprise to us. … So we have seen a variety of surfaces, a snow field of soft stuff, and this rocky field of rock stuff, which could be a [stronger material], and we also see this shiny stuff,” which he says could also be a stronger material.

How do you find the first photos from the surface of a comet? The Guardian’s Roger Tooth isn’t all that impressed.

Of course this is a miracle: a huge rock in space, 300m miles away, moving at 40,000mph, and here’s our little craft snapping away as it bounces down on to it. It’s a miracle, but the pictures when they come through are a disappointment photographically. They’re in black and white and there’s some sort of landing leg in the way. The images have a pioneering magic, but not the beauty of the 1968 Earthrise image taken by a moon-orbiting Apollo 8 or the 1972 beauty that became known as the Blue Marble picture of Earth.

You can read more about Roger’s thoughts and judge the photos for yourself here.

With Philae “permanently in the shadow of a cliff”, according to Dr Bibring, Esa has to consider whether an attempt to nudge or secure the lander is worth the risk of toppling it.

Bibring said Philae is probably “a couple of meters” from the cliff face, and lander manager Stephan Ulamec said the lander’s orientation was “bizarre, or not so obvious”, and would require very careful adjustment, if any. My colleagues Ian Sample and Stuart Clark have more on the decisions Esa must mull:

The spacecraft was designed with landing gear that could hop the probe around, but from its awkward position on its side the option is considered too risky.

But the team has decided to operate another moving instrument, named Mupus, on Thursday evening. This could cause Philae to shift, but calculations show that it would be in a direction that could improve the amount of sunlight falling on the probe. A change in angle of only a few degrees could help. A new panoramic image will be taken after the Mupus deployment to see if there has been any movement.

Esa will also try to move the solar panels to maximize sunlight; you can read the full piece on Philae’s challenges here.

An image taken from 50km, about a week before landing, showing the spot Philae touched down – “we couldn’t have had better luck. It’s flat, flat like hell, which is great.”

That’s a project manager during today’s earlier Esa briefing, he’s happy but a bit rueful: “We wished it would’ve stayed there, but it didn’t.”

Lead lander scientist Dr Jean-Pierre Bibring earlier today said that one of Philae’s legs is sticking out into space, possibly over a crater or ditch.

“We’re almost vertical, one foot probably in the open space … two feet still on the surface, but you can imagine the gentle maneuver that we’re supposed to do now to maintain” Philae’s position, he said.

One of his colleague’s added that Philae isn’t “standing, let’s say, parallel to the surface, so we need to modify the plans … to cope”. As Stuart and James noted earlier, even the rotation of a drill could dramatically change how Philae stands on the surface.

The UK office is now handing over the reins of this blog to our colleague in the US, Alan Yuhas, who will keep bringing you the latest news from this extraordinary story of space exploration.

Here’s a Guardian interactive graphic illustrating Philae’s predicament.

Using the panoramic image series just posted on this blog, the Philae lander team have superimposed a sketch showing their best guess for the orientation of the craft relative to its surroundings.

Esa has just released this panoramic image series of the wall of rock in front of Philae, captured by its ÇIVA-P imaging system. Six identical micro-cameras are designed to take pictures of the surface. A spectrometer then studies the surface’s composition, texture and albedo (reflectivity).

Dr Daniel Brown, an astronomer at Nottingham Trent University, thinks this mission tells us something about scientists as well as science:

Philae has been on the comet for just one day, but the sense of tension and awe it has created has been remarkable. It is a huge relief to hear that Philae is still functioning and gathering data and images. The amount of emotion we have seen from the team since the landing shows that science does not come from the head alone, but from the heart and soul too. Space and planetary exploration is touching the very core of what we are about, challenging the impossible and shedding light on the unknown. One look at the images sent back from Rosetta and Philae confirm this.

The predictability of Newton’s laws has emboldened the scientists to deploy part of the MUPUS instrument tonight. This could cause Philae to shift, but calculations show that it would be in a direction that could improve the illumination.

Even a few degrees more illumination could help recharge the lander’s batteries. To date, Philae has generated enough power for just 90 minutes out of a hoped for 6-7 hours.

A new panoramic image will be taken after the MUPUS deployment to see if there has been any movement.

In parallel, there is a big effort from the Rosetta orbiter team to try to pinpoint Philae’s position. This will be done with images from the Osiris camera and with the CONSERT radar instrument.

CONSERT communicates with Philae. It is designed to beam radar through the interior of the comet to reveal its internal structure. When Rosetta is directly overhead, CONSERT can provide highly accurate triangulation.

“When we see where we are, we can decide what to do next,” says Jean-Pierre Bibring, lead scientist for the lander.

But time is tight, the first 24 hours of the battery life will soon be gone. It is expected to be completely drained sometime on Saturday.

“We are running against the clock,” admits Bibring, “Don’t put the emphasis on failure, it is gorgeous where we are.”

Engineers at Esa have calculated that the touchdown velocity was 1 m/s, slower than expected. Without the harpoons as anchors, Philae rebounded with a velocity of 38cm/s and conducted a leisurely jump for two hours.

In that time, it is now thought that Philae reached a altitude of about 1km and drifted about 1km away from the original site. On a comet of just 4km in length, that is quite significant.

The second jump was just for a few minutes and resulted in the lander coming to rest somewhere in the original landing site candidate known as site B.

Philae is thought to be resting somewhere in candidate landing site B, shown here. The exact location of the lander is unknown but it is probably toward the bottom right of the image. Originally this landing site was rejected by Esa on account of the large boulders and the poorer illumination than site J, which was chosen and became known as Agilkia.

Here’s a reminder of Philae’s rather restricted view, at the foot of what appears to be a cliff, or the bottom of a very deep hole.

In this new image released by Esa, the circled speck is the Philae lander during its descent. The picture was taken by Rosetta’s OSIRIS wide-angle camera at 14:19:22 GMT on Wednesday.

This image was taken by the ROLIS camera on Philae when it was 40 metres above the surface. It suggests a very loose, dusty surface.

The red cross-hairs mark where Philae first hit the ground before bouncing. This image was taken by the OSIRIS instrument on Rosetta from a distance of 30 kilometres back in September. It is thought that Philae bounced twice before settling on the surface. It may have come to rest at the foot of the cliff surrounding the depression, in the lower right corner of the image.

Jean-Pierre Bibring, however, points out that drilling to take samples for isotopic analysis is critical to the whole scientific purpose of the mission. With time running out, he hopes that this might be given the green light as soon as tomorrow.

Stephan Ulamec explains that activating any moving parts will be high risk, tipping the lander or pushing it away from the surface completely: “Drilling without being anchored is dangerous.” The same applies to any attempt to fire the harpoons.

The landing gear was designed to “hop” to relocate the craft, but without knowing whether the feet are in contact with the surface this is not currently a viable option to move it to a more suitable position - away from the cliff face.

But there’s clearly a variety of surfaces on the comet, rocky and dusty, which may explain the bounces.

Chances are the comet is made of a very low-density material, without a hard crust.

Early images of the ground were overexposed, making it impossible to spot the lander, but subsequent images waiting to be downloaded from Rosetta will be more accurately exposed.

Timelapse of pictures from Rosetta reveals Philae rotating as it came down. One of the images is so clear you can see the lander’s solar panels.

These are the first images before processing.

That was Stefano Mottola from the Lander Control Centre in Cologne, Germany, describing the nature of the material revealed on the surface of the comet and how it may have got there. “The images provide a wealth of data that will keep us busy for some time to come.”

“The lander is relying on solar energy ... we’re getting one and half hours of sunlight when we expected six or seven. This has an impact on our energy budget.”

The lander was spinning as it came down. When it stopped they knew it had finally come to rest.

The first landing was on target, followed by a huge jump. The likely current location area of the lander suggests it may be facing the rim of a crater.

CONSERT is a radar instrument on Rosetta designed to probe the interior of the comet. It is being used to triangulate the exact position of Philae.

This is Stephan Ulamec speaking. He’s Philae lander manager at the DLR German space centre.

They’re going to try to “modify the orientation” to get more light on the solar panels.

“Astonishing” image from camera 4. The view is of rock not a powdery surface as was expected.

This is Jean-Pierre Bibring of the Institut d’Astrophysique Spatiale in Paris, who has spent almost two decades working on the Rosetta mission. He is the principal investigator responsible for the CIVA camera that has been taking selfies of Rosetta and the comet.

Four new images about to be revealed. Two other images were merged to give us the image they released to the world earlier today.

“Yesterday was great but today will be even bigger.”

These are yesterday’s highlights playing on the livestream now. Today’s update has yet to start.

You have to wonder how clear heads will be after yesterday’s excitement and the celebrations that must surely have followed.

The press conference is about to start. Watch it on the livestream at the top of this page.

Apparently the lander did receive some power from its solar panels, but it appears that parts of the craft were in shadow while last night’s surface telemetry was being transmitted.

Teams are still working to confirm the lander’s location and the overall power and thermal situation on board. Nonetheless, it appears to be performing well.

The ESA Rosetta blog is reporting:

The lander did receive some power from the solar panels on Wall No. 2, but it appears that parts of the lander were in shadow during the time that last night’s surface telemetry were being transmitted.

This could be worrying. Solar power is essential if Philae is to survive longer than the original 60 hours battery life.

“Philae is on the surface and doing a marvellous job, working very well and we can say we have a very happy lander,” says Paolo Ferri, Esa’s head of mission operations at ESOC.

Flight director Andrea Accomazzo adds that during the second lander-orbiter communication slot, which ran from 06:01 GMT until 09:58GMT this morning, “We had a perfect pass; the radio link was extremely stable and we could download everything according to the nominal plan.”

Here’s the livestream from mission control in Darmstadt.

A key observation for helping determine the exact landing spot will be the day and night cycle of the comet. The Agilkia landing site was chosen because of its good illumination but the comet’s rotation means that it will sometimes be in darkness.

Timing exactly when this happens using data from the solar panels or other instruments will provide a valuable piece in the puzzle when tracking down the final landing spot.

A French Space Agency (CNES) official has just said that he thinks of the Philae landing as being like a baby goat bouncing up and down! That might be a loose translation – he was speaking in French.

The hunt for Philae continues. It is not yet know exactly where Philae is located on the comet but the thinking is that the lander is not too far away from its original target point.

The lander bounced twice yesterday, finally coming to rest two hours after the original touchdown.

Contact was re-established with Philae this morning around 6:00 GMT, just two minutes after the window opened.

Fred Jansen, Rosetta mission manager, told me, “Yesterday there were people who said that if the lander jumped up and was hovering for an hour or two, the comet would rotate underneath it and then you could be anywhere. But to see the signal so close to the planned time means that we must be close to our original landing spot.”

The good news from mission control is that scientific data is flowing in, even though the communications link between Philae and Rosetta remains intermittent.

“We have telemetry and massive data already. This is a success,” says mission manager Fred Jansen.

We still don’t know the exact location of Philae. Ingenious Esa engineers are planning to use the radar instrument CONSERT to triangulate its position. The instrument on Rosetta is designed to probe the comet’s subsurface using radio waves, which are pinged back to the orbiter by a transponder in the Philae lander.

During the descent, CONSERT showed that the lander was just 50 metres adrift from the targeted landing spot. Esa had planned for the error in position being up to 500 metres.

Of course, that was before those two slow-motion bounces. Magnetic field data from Philae’s ROMAT instrument revealed three “landings”. The first was almost exactly on the expected arrival time of 15:33 GMT. But as we now know the anchoring harpoons did not fire and Philae rebounded.

In the weak gravity of the comet it took about two hours for the lander to return to the surface after that first bounce. It touched down for a second time at 17:26 GMT, then bounced again before finally coming to rest at 17:33.

We’ve been promised four more pictures from the press conference at 1pm GMT forming the first 360° panorama of the surface. Worryingly, an Esa official has let slip that there “may” not be a horizon visible in those either.

The image released this morning comprises two CIVA images from the full panorama of six images that will be released at 1pm. These will show the other two legs of the lander, and provide a full panorama of the landing site. CIVA itself comprises six micro cameras dotted around Philae’s body.

There will be a press conference in Darmstadt at 1pm GMT revealing what the scientists have gleaned from the data coming back from Philae. We’ll livestream that and report the highlights here. The suspicion is that the lander is in a crater or facing a cliff.

A mosaic of two images taken by the lander’s CIVA camera shows one of Philae’s legs and the craggy surface. Esa had been expecting a view of the horizon … “We’re either looking into a ditch or we are against a wall,” project scientist Matt Taylor has told our astronomy blogger Stuart Clark.

Here’s video from the press conference on Wednesday evening including Stephan Ulamec, the Philae project manager explaining their initial thoughts about what happened during the bouncy touch down.

Here’s an update from Esa’s main control room. They say that contact with the lander was re-established at 6:01 GMT and then lost again at 9:58 GMT. This due to the Rosetta mothership dipping below the comet’s horizon. In that time the scientists were able to receive science data from the surface.

The team are planning a rocket burn by Rosetta on Friday to keep it in position.

• Rosetta is operating nominally; the network systems and overall ground segment to control the mission are nominal

• Last night, Rosetta lost contact with Philae as expected when it orbited below the horizon just after 20:00 CET.

• Contact was re-established this morning at 06:01 UTC / 07:01 CET, and the Philae-Rosetta radio link was initially unstable.

• As Rosetta rose higher above the Philae landing site, the link became very stable and the lander could transmit telemetry (status and housekeeping information) and science data from the surface.

• This morning’s surface link was again lost due to Rosetta’s orbit at about 09:58 UTC / 10:58 CET. Ignacio [Tanco, deputy spacecraft operations manager] explains that with the current orbit, Rosetta will have, typically, two Philae communication windows per day.

• The next window opens at 19:27 UTC on the spacecraft and runs through to 23:47 UTC spacecraft time.

Esa has released a video of highlights from last night’s press conference providing detail about the touchdown.

Esa reports that mission control is optimising Rosetta’s orbit for communication with the Philae lander. Rosetta conducted a thruster burn last night and plans are being made today to carry out another burn on Friday to keep the spacecraft in the best position.

Rosetta is sending signals to ground stations at about 28 kilobits per second. Ignacio Tanco, deputy spacecraft operations manager, says about 1 or 2 kilobits of this is used for the spacecraft’s own telemetry report, with the rest being used to download science data from Rosetta and science and telemetry data from Philae.

It is magnetic field data from Philae’s ROMAP instrument that revealed the three “landings”. The first was almost exactly on the expected arrival time of 15:33 GMT. Philae then rebounded by hundreds of metres. In the weak gravity of the comet this bounce took about two hours. It touched the surface again at 17:26 GMT and bounced again before coming to rest at 17:33 GMT.

Lander project manager Stephan Ulamec has told the BBC’s Jonathan Amos:

We are still not anchored. We are sitting with the weight of the lander somehow on the comet. We are pretty sure where we landed the first time, and then we made quite a leap. Some people say it is in the order of one kilometre high. And then we had another small leap, and now we are sitting there, and transmitting, and everything else is something we have to start understanding and keep interpreting.

Dr Matt Taylor, project scientist on the Rosetta mission, describes the bumpy landing (including one nearly two-hour bounce) 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.

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. We know it’s stable and sitting in place - that’s about as stable as we could wish for at the moment - and the next few hours should give us a bit more illumination on what the situation is there.

It seems that even David Cameron was watching while on his way to the G20 summit in Brisbane.

And here’s Philae’s take on the events of yesterday. The first bounce took nearly two hours! This was a result of gravity on the comet being so weak.

That image was taken by CIVA (the Comet Infrared and Visible Analyser) which is described by the scientists at the Open University in the UK thus:

The first experiment, CIVA-P, consists of seven identical cameras that will produce a panoramic image of the comet as seen from Philae. CIVA-P will characterise the landing site, mapping the surface topography and the albedo (reflectivity) of the surface. Two of the camera are aligned so as to produce stereoscopic images.