History beckons for Rosetta comet mission

Nov 10, 2014

By Jonathan Amos

All is on course for Wednesday’s ambitious attempt to put a probe on the surface of a comet.

Europe’s Rosetta spacecraft is currently making a long arc around 67P/Churyumov-Gerasimenko.

Shortly after 06:00 GMT, the orbiter will make a sharp turn towards the ice mountain, accelerate, and then eject the Philae robot towards its target.

Separation should occur at about 08:35 GMT. Touchdown is expected roughly seven hours later.

There are a series of major decision points in the run-up to the ejection – what the controllers back here on Earth call Go/No-go decisions.


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29 comments on “History beckons for Rosetta comet mission

  • It seems to be going to plan so far.

    Controllers report both mothership and descent robot to be in excellent shape.

    The landing commands on Philae have already been loaded, and an instruction was sent up on Monday evening to switch on and warm the probe.

    The intention now is to leave it in an active state, ready for the separation.
    This is timed to occur at 08:35 GMT on Wednesday.

    Touchdown should follow about seven hours later, with a confirmation signal expected back on Earth around 16:00 GMT.

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  • 2
    NearlyNakedApe says:

    Yes… I’ve been following this story for about a year now and I can’t wait to see how it turns out. So far, it’s looking good indeed but it’s got to be a major nail biter for the people at mission control right now.

    Go Philea!!

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  • 3
    aroundtown says:

    What a major accomplishment for the European space agency and all those involved who worked and planned for this day. Amazing, awesome, and any other accolades I can think of seem insufficient. LANDING ON A COMET!!!!!!!!!!! I’ve lived to see the landing on the moon, mars, and now this. Love it.

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  • 5
    NearlyNakedApe says:

    Woot!! Bravo to the entire team of scientists, engineers and technicians who made this possible. I was lucky enough to catch the live coverage about 40 minutes before the confirmation of landing. What a privilege to be able to witness such a historical moment as it unfolds.

    Can’t wait to see the images and data from Philae.

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  • Congrats to ESA! Thrilling to watch CNN’s reporting – perfect combination of science & passion discussion. A side note, one anchor said something along the lines of “this is fun for us science geeks”. I can’t imagine not being excited, but know many are not (costs, etc.) – and what a shame, the mission being such a positive work of humanity.

    Allow me to say, the Philae lander is cute as a bug (albeit no bugs, of course!).

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  • Marktony Nov 12, 2014 at 4:30 pm

    In the Frontiers programme on Radio 4 they said that the harpoon didn’t fire and that the probe may have lifted back off and then re-landed.

    The gravity on the comet is tiny, so even a slight force could lift the probe off it if it is not anchored.
    There is evidence that “rubble-pile” comets and asteroids, are separate pieces held together by their tiny gravities, but only in the absence of other gravitational forces (such as nearby planets).
    That is why Comet Shoemaker-Levy 9 broke up as it approached Jupiter. http://www2.jpl.nasa.gov/sl9/

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  • It seems the lander bounced twice and is now in a position where it is in the shadow of a cliff, so only gets about 1½ hours of sunlight when it was planned to be in a more open site, where it got 5 or 6 hours on its solar cells to recharge its batteries.

    Apparently because the gravity is so low, using its landing gear, its arm, or its drill, could push it off for another jump, but this could turn it over, or put it in a worse position with even less light.
    ESA have big decisions to make, but planned for the core science to be done on the batteries, before needing the solar recharging to extend the work.

    The Rosetta orbiter, will continue to function for a couple of years or so, regardless.

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  • 14
    Tintern says:

    So incredibly exciting to see this. Hopefully stability and anchoring and landing site problems can be resolved. I’d love for them to be able to risk drilling and so find out as much as we can about composition. However, it’s such a triumph of knowledge, passion and skill to have done this. Just thinking about that thing “we” made, all the way out there, is mind-blowing. It’s not warp drive but I think it’s time for Starfleet to beam Picard down and invite us to join United Federaton of Planets.

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  • 15
    NearlyNakedApe says:

    As soon as I learned that the harpoon had not fired and that Philae was not anchored to the ground, I was worried that it would jeopardize the mission. The main experiment being SD2 (drilling the soil for sample analysis) cannot be performed unless the lander is firmly anchored in the ground. And the clock is ticking…

    The charge in the main batteries will last only 50-60 hours and even if the solar panels were in a favorable position and orientation (which they aren’t), the secondary battery isn’t powerful enough to actuate SD2.

    Perhaps it’s too early for this and I might get flack for it, but what the heck…

    I’m speculating that sometime in the next 48 hours, they will have no choice but to risk firing the harpoon again because let’s be honest here: SD2 is the main purpose of the mission. And if push comes to shove, it’s better to risk throwing the lander off the surface than missing out on a once in 20 years opportunity to sample the inside of pre-solar system comet.

    It would be wise however to attempt this last-ditch maneuver only after most of the other scientific experiments have been performed to minimize the loss of data should the worst case scenario occur.

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  • An absolutely wonderful achievement.

    However, since the anchor harpoons failed to deploy, Philae is extremely vulnerable; there’s hardly any gravity. It’s also sitting in a crater and will only get a couple hours of sunshine a day, so the batteries might go flat. Nonetheless, the ESA teams are able to carry out fabulous science.

    I think it’s a greater achievement than the Moon landing, and I’m glad I’m alive to see it.

    Moderators, I’ve just had a thought, so would you please permit me to digress briefly.

    When I was a little boy, a tall slim man with dark hair who was a supply teacher at my school would enthuse movingly about planets, space, space exploration, music and poetry.

    I remember us sitting on chairs next to one another, with him reading stanzas to me, which I would recite back to him verbatim; he clearly found it fascinating that a nipper as young as me could do that.

    I have a school photograph, in which, by the time the photographer had set up, said teacher, although still sitting bolt upright with his arms folded, had dosed off; his name was Patrick Moore.

    And I think it’s a pity that he’s not still alive to see it too.

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  • This is one of the coolest things I’ve seen in a long time. Well done. But being a cynic I always have to find the dark lining in every cloud. I was listening to one of the heads of the European space agency (rightfully) crowing about this and it got a little absurd at one point. “This shows how great the European space program is because WE were the FIRST to get to a comet!” It seems they are picking up some of the worst habits of NASA… although even NASA doesn’t do much of that anymore… then again NASA hasn’t had much to talk about lately so that might be the reason. Anyway, I just wish when people talked about this it was more in terms of the great new knowledge we are acquiring, how cool it is that the Europeans can work together on this, that sort of stuff rather than the jingoistic “We were First suck it Everyone Else!” kind of talk.

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  • Patrick Moore

    Sir Patrick Moore? Way cool – never heard of him until A4D made mention.

    If I understand correctly, the lander’s cold-gas system for thrust did not pressurize, thus, no guidance for favourable touch down spot(s). To paraphrase someone involved “we learn as we go, so keep going!”.

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  • Red Dog Nov 13, 2014 at 2:46 pm

    “This shows how great the European space program is because WE were the FIRST to get to a comet!”

    This is a second major extraterrestrial landing well beyond the Earth /Moon system, following on from ESA’s Huygens atmospheric entry probe that landed successfully on Saturn’s moon Titan in 2005.

    It seems they are picking up some of the worst habits of NASA…

    NASA has had plenty to be proud of in the Mars Rovers etc.
    Some of the public need to be reminded of the talent and dedication needed to achieve these results.

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  • Having got some data, ESA are now going for the riskier options.

    Scientists working on Philae comet lander say it is time to take more risks with the probe, amid fears its battery might die in hours.

    There is an expectation that the robot may be entering its last day of useable power on the ice object 67P.

    The European Space Agency (ESA) is due to upload commands to tell Philae to deploy its drill.

    The hope is that it can pull up some samples to analyse in the robot’s onboard laboratories.

    It is a high risk activity, however, because the torque could destabilise the delicately placed lander.

    Follow-up imagery by Rosetta should now find the little craft, says Paolo Ferri, the head of mission operations at the European Space Agency.

    He said Friday’s activities would be critical.

    “We’re coming to the end so we’re taking more risks. But we’re super happy with what we’ve done up until now. I can’t tell you exactly how much this lander has achieved but it is close to 100%.

    “What’s missing is the drilling. But with time running out, we’re taking risks.

    Dr Ferri refuses to give up hope that some last minute solution can be found to solve the power situation: “I am sure our colleagues at the main lander control centre in Cologne will come up with creative ways to collect this energy.

    One solution that will be tried on Friday is to turn the main body of the robot to show the largest of its solar panels to the Sun.

    The idea is that this could eke out some more life for the lander.

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  • 21
    NearlyNakedApe says:

    I agree. In a world where most of the attention, credit and glory is hijacked by gluten-free Hollywood actors, arrogant Hip-hop gansta rappers, GF-beater sports celebrities and exhibitionist stage performers of questionable talent, it is only fitting that some of those bragging rights be reclaimed by the truly brilliant and talented people that actually shape the future of mankind.

    As far as I’m concerned, NASA and ESA can brag all they want about their exploits. If you’ve earned it, then OWN it.

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  • 22
    NearlyNakedApe says:

    The people at ESA have decided to activate the drill…

    “Philippe Gaudon, an ESA project manager, said that by using that power, Philae was able to successfully deploy its drill and bore 25 centimetres into the comet’s surface to start collecting samples”

    But now the problem is as Scotty would put it… “Captain, we’re running out of power”. The good news is that the mechanism has worked but the bad news is that the link was lost and the battery may have run out of power by the time contact is re-established.

    Contrarily to what I thought earlier, Philae was able to drill the surface without the harpoons being anchored in the ground. I’m guessing that the probe being stuck in a hole, wedged in between some rocks may be what made drilling without pushing the probe off the comet possible.

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  • After all the decades of diligent hard work and study by the team members to gain the qualifications and skills necessary to bring the mission about, and the meticulous design and calculations involved in it, and after successfully locating the target and touching down on it after ten years in space, only to land in the shade without anchorage is the most awful luck.

    Oh well, as my old mum used to say, I don’t know whether to laugh or cry.

    She would also remark that you can’t get through life without a sense of humour.

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  • Philae comet lander sends more data before losing powerhttp://www.bbc.co.uk/news/science-environment-30058176

    The Philae lander on the distant comet 67P has sent another stream of data back to Earth before losing power.

    The little probe delivered everything expected from it, just as its failing battery dropped it into standby mode.

    Philae is pressed up against a cliff. Deep shadows mean it cannot now get enough light on to its solar panels to recharge its systems.

    The European Space Agency (Esa) fears this contact may have been the robot’s last – certainly for a while.

    . . . .

    But with only 1.5 hours of sunshine falling on the robot during the comet’s 12-hour day, it seems doubtful the battery will have recovered enough performance to complete the radio link.

    Engineers did manage to maximise the possibility of it happening, though, by sending a command to reorientate the lander.

    This involved raising Philae by 4cm and rotating its main housing by 35%. This will ensure the largest solar panel catches the most light.

    Even if the probe falls silent over the weekend, researchers say they are thrilled with the amount of data already acquired.

    Stephan Ulamec, lander manager, said: “Prior to falling silent, the lander was able to transmit all science data gathered during the First Science Sequence.

    . . .

    Professor Mark McCaughrean, senior scientific adviser to the ESA, told BBC Radio 5 live they were “hugely happy”.

    He said: “All of the science instruments on board have done all the work they were supposed to do so we have huge amounts of data back on the ground now, which is really exciting.

    “Philae could come back later as we move closer to the sun, and we get more light onto the solar panels up against the cliff we’re at here in the shadows.”

    In the latest tranche of data are the results from the drilling attempt made earlier in the day.

    This had been an eagerly anticipated activity. Getting into the surface layers and bringing up a sample to analyse onboard was seen as central to the core mission of Philae.

    Controllers say Cosac, the Philae laboratory that was due to receive the sample, downlinked its data, but that its contents had yet to be assessed.

    . . .

    Among other returns, Philae took another picture of the surface with its downward-looking Rolis camera.

    It also exercised its Consert instrument. This is an experiment that sees Philae and Rosetta send radiowaves through the comet to try to discern its internal structure.

    Knowledge of that final resting location would enable engineers better to understand its predicament and the prospects for future contact if lighting conditions somehow change on 67P.

    This could happen as the comet moves through space on its journey around the Sun. It will have the equivalent of seasons, and this could play to Philae’s advantage by altering the angle, timing and intensity of the sunlight hitting the solar panels.

    It has lost power, but has done the job it was designed to do.

    There is also the possibility of a slow recharge of batteries and better lighting conditions, as the comet moves into the inner solar-System towards the Sun.

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  • 25
    NearlyNakedApe says:

    This is very good news. Just made my day.

    Late afternoon yesterday, when contact with the lander had been lost, I was worried that the battery had just died there and then and that Philae wouldn’t be able to transmit the data gathered from SD2 and COSAC. I must admit that I am pleasantly surprised by the outcome. Mission accomplished… in extremis. Whew!!

    However, even if SD2/COSAC hadn’t worked, landing this refrigerator sized probe on a comet at half a million kilometers from earth is an amazing accomplishment in and by itself. Congratulations to the entire ESA team for their exploit, this is a major landmark in the history of space exploration.

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  • NearlyNakedApe Nov 15, 2014 at 9:48 am

    Late afternoon yesterday, when contact with the lander had been lost, I was worried that the battery had just died there and then and that Philae wouldn’t be able to transmit the data gathered from SD2 and COSAC.

    Contact is regularly “lost” when a lander is using an orbiter as a relay transmitter to take signals back to Earth.
    The same thing happens with Mars Rovers, when the orbiting satellite the lander is transmitting to, is on the opposite side of the planet, with the solid body blocking its signal.

    The worry was that the battery may have died before the Rosetta orbiter came back into the lander’s field of view to receive the transmissions.
    Timing is everything when communication windows are intermittent.

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  • Stafford Gordon Nov 13, 2014 at 2:08 pm

    I have a school photograph, in which, by the time the photographer had set up, said teacher, although still sitting bolt upright with his arms folded, had dosed off; his name was Patrick Moore.

    For those in the UK who are interested, his successors, running his “Sky at Night” astronomy TV programme, are presenting a one hour special on Rosetta tonight (Sunday) at 9pm on BBC4.

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  • .High-resolution pictures have now been released of the Philae probe in the act of landing on Comet 67P last Wednesday..

    They were acquired by the Narrow Angle Camera on the Rosetta satellite, which had dropped the little robot towards the surface of the “ice mountain.”

    The images are presented as a mosaic covering the half-hour or so around the “first touchdown” – the probe then bounced to a stop about 1km away.

    Here is a link to a selection of articles day-by day: –

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  • The data analysis from Philae has got under-way!


    Comet landing: UK team’s data bonanza from Philae

    UK Researchers received “rich” data from the Philae lander just before its power died.

    Scientists say they detected what might be complex carbon compounds on the surface of the comet the craft landed on two weeks ago.

    he results are from the Ptolemy instrument, which is a miniaturised on-board laboratory.

    The detection of carbon supports a view that comets may have brought key chemicals to Earth to kick-start life.


    Much of the data gathered by Ptolemy was collected on the fly. Shortly after the Rosetta spacecraft was activated in January, Prof Wright and his team saw the opportunity to analyse the comet’s tail as the spacecraft approached.

    “It is not something we had planned to do, but it became obvious that it was something we could do.

    The early data suggests that the composition of the gases changed as the spacecraft got closer to the comet.

    Prof Wright also explained that Philae’s bouncy landing suited his experiment. Among Ptolemy’s capabilities is the ability to analyse gases and particles around it, and so it was pre-programmed to sniff its environment shortly after landing.

    Pictures from Rosetta show that the first landing created a dust cloud, providing Ptolemy with a feast of data.

    The hardest moment for the Philae team was having to abandon plans to analyse material drilled from underneath the comet’s surface. Overall, programme managers deemed that there was only sufficient battery power to drill for one sample, rather than two as was originally planned. A collective decision was therefore made that any sample should be analysed by the German-led COSAC instrument – not Ptolemy.

    But mission planners did grant the UK team Philae’s last ounce of strength to operate Ptolemy’s oven, to heat up all the debris that had collected inside the instrument to 200C and analyse the gases that came off.

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