Philae, the ‘happy lander’

"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 today.

During the second lander-orbiter communication slot, which ran from 06:01 UTC / 07:01 CET until 09:58 UTC / 10:58 CET this morning, "We had a perfect pass; the radio link was extremely stable and we could download everything according to the nominal plan," adds Rosetta Flight Director Andrea Accomazzo.

Credits: ESA/Rosetta/Philae/CIVA

Credits: ESA/Rosetta/Philae/CIVA

Here are details:

First analysis of the touchdown data suggests that the lander bounced twice before settling on the surface of Comet 67P/C-G. The lander remains unanchored to the surface, but the instruments are running and are delivering images and data.

After touchdown at 15:34 UTC (confirmed at 17:02 CET), a clear strong signal was received, with some breaks. Lander telemetry stabilised at about 17:32 UTC and communication with the surface was maintained until the link to the orbiter was lost at 17:59 UTC due to Rosetta's orbit; this was about an hour earlier than predicted for the target landing site (most likely due to local horizon interference).

Later on 12 November, after analysing lander telemetry, the Lander Control Centre (in Cologne) and Philae Science, Operations and Navigation Centre (SONC, Toulouse) reported;

  • There were three touchdowns at 15:34, 17:25 and 17:32 UTC; in other words, the lander bounced
  • The firing of the harpoons did not occur
  • The primary battery is working properly
  • The mass memory is working fine (all data acquired until lander loss of signal at 17:59 UTC were transmitted to the orbiter)
  • Systems on board the lander recorded a rotation of the lander after the first touchdown. This is confirmed by ROMAP instrument data, which recorded a rotation around the Z-axis (vertical).

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

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

Comments

82 Comments

  • Jon says:

    CNES confirms: #Philae is currently located at ~1 kilometer from..initial touchdown point. #CometLanding”

    • Martalien says:

      I think, it could be possible turn the module around one leg. Only when it is possible control the drills on the legs. Two drills from three must be unscrewing from the surface and the modul can turn about the third leg into better position .

    • broomberg says:

      ...can the drilling mechanism be used to shift philae to a better position?

      • belial says:

        If they had the top thruster, they could probably "walk" the lander on it's legs by leaving one screwed, rotating it, pushing down, screwing another in and unscrewing the rest, rotate, push down ad infinitum.

    • quezween says:

      Do no what will happen in the future. this so exiciting than any thing i have ever seen

  • Yann says:

    Is there any chance the harpoons can be fired ?
    What are the possible issues if not ?

  • So what are the plans for the anchoring situation? Is there a chance Philae will hop to a new location due to orbital mechanics?

    • Peter Foele says:

      Is there a possibility it has hopped off the 'head' of the comet and is now resting somewhere in the neck?

    • Graham Hall says:

      while the lander does have some hop capability, it normally requires 3 feet in contact with the surface. It seems that Philae is on its side and its not clear what is in contact with the surface. I'd wager that the team will get all they can from their experiments before they attempt anything that will change the orientation - for fear of making things worse.

      Possibly the drill arm could be utilised to try and improve matters as well. The engineers will do all they can to improve things - look at how NASA kept the rovers going (even backwards) after wheels stopped working.

  • Piot says:

    Hello,

    Is this typo? First touch down at 15:34!?!?
    That seems pretty early and such a big bounce compared to the others.

    Nevethelmess, great job Philae!
    I am looking forward the CONSERT data.

    • Donal says:

      Not a typo. That was the predicted landing time anyway. First bounce would be expected to be higher than the second, I would imagine?

    • Luis says:

      Keep in mind that gravity on the comet is extremely small, about 10/100 millionths of the gravity on earth. So once it bounced the first time it had very little gravity to accelerate it on the surface, thus resulting in a very large delay.
      But yeah, this is yet another science experiment that will propel us further into tomorrow's technology! Very excited.

    • Larry says:

      Drop a soccer ball on grass and it will bounce a few times. Each bounce will be lower and briefer than the last.

  • Cyro says:

    Great job. you were fantastic !!

  • Adrian says:

    Firstly, Congratulations from an Argentinian in Crimea ))

    Now a question: When you say "There were three touchdowns at 15:34, 17:25 and 17:32 UTC; in other words, the lander bounced" it means that it was floating from 15:34 until 17:25? During 111 minutes?

    Why the first bounce lasted 111 minutes and the second and last only 7 minutes?

    Congrats again, keep up the good work!

    • Reynald says:

      First bounce duration was 112 minutes (to 450 m heigh), and second bound duration was about ten minutes (to 3 meters heigh) ; that normal according to the very low gravity on 67P.

    • Graham Hall says:

      Because the landers legs operate like a shock absorber on a car. If you press down on one corner of the car hard and let it go you get 2/3 decreasing oscillations until the car returns to rest.

    • Larry says:

      Being small, the comet's gravity is low. It took 55 minutes after the first touchdown for its low gravity to stop the rise of the rebounding lander and another 55 minutes for the falling lander to return to the ground. Each impact absorbed energy so the rise after the second touchdown was lower and briefer than the rise after the first. The third touchdown absorbed so much of the remaining energy that it did not result in a detectable bounce.

  • Atanas Matev says:

    Is it possible to instruct Philae to fire its harpoons from Earth?

    • Graham Hall says:

      yes but no guarantees that they would work or what the effects would be!

  • Jean Vallee says:

    What is the implication of the harpoon NOT firing? Could it means that Philae could fly away or is the gravity enough to keep it there? I tought that screws where at the end of the leg, will you be able to use them if you don't have the harpoon? So many questions, but I was so glad when I heard of the landing.

    • USA Citizen says:

      I think what they are doing is first analyzing if the current location is sufficient for performing the functions they need and if the craft will receive enough solar power to keep going. If not, they may want it to change position before screwing it in there. How they do this exactly is unknown to me.

      • Tad in New Mexico says:

        I, too, am an American citizen, and I, too, congratulate the European consortium that made the orbit and and landing happen. It is an exiting achievement for all of the world, and it is an ongoing thrill to watch the lander-orbiter tandem do their work so well, even while acknowledging the unexpected last minute events. Good decision to go without the thruster, despite the limitations imposed thereby. Nothing but praise and excitement from me. We're going to miss Philae when it gets ejected too close to the sun, but we'll be a whole lot more informed by then. More than anything else, congratulations on a job well done. It helps bring the world together on an important event, and it is always good to have an event that the cynics among us don't know how to get cynical about! I look forward to more--as much as we are treated to, for as long as it can last.

  • Carlos Cuervo says:

    Es increible el avance logrado, es como haber pisado la luna por una Segunda vez a mi manera de ver. Y abre una nueva pregunta, podremos resolver el problema combustible y alcance de viajar por el espacio investigando otros mundos aprovechando la potencia de los cometas Felicidades

  • PeterK says:

    Wow, is Philae then still at about the right landing site or has it jumped away to somewhere else?
    is it possible for Rosetta to take a Picture of Philae on the surface? What about the ice screws, did they also malfunction like the harpoons?

    • USA Citizen says:

      It is definitely not on the original landing target location but somewhere close (they predict). The screws haven't been used yet according to the updates we've received up until now. Not sure if they can still trigger the harpoons to fire remotely or not.

    • Adrian says:

      Rosetta is orbiting 67P at an altitude of 29 km (18 mi), and Philae has the size of a washing machine. I think it would be impossible to take a photo of him on the surface, at least from that distance.

    • Graham Hall says:

      Lets assume that the lander came down vertically. It then was in space (nearly said air!) again for circa 110 minutes. The comet rotates in about 12.7 hours. it "could" have touched down in a very different place. That's the worst case. As it is, its though Philae landed finally in an adjacent large depression (crater?) about 1KM from the initial landing point, which appears to have been almost exactly on target.

    • Graham Hall says:

      The landing sequence was for the downward gas thruster to operate when the surface was detected to prevent bounce and give time for ice screws to work. Then the harpoons to fire (some sort of explosive propellant) and then be wound back in to lock Philae to the comet,

      Since the gas thruster AND the harpoons didn't work, the ice screws perhaps didn't have time to work, or if they did work were unable to prevent the recoil bounce from lifting the lander. As I understand it the energy for the screws came from the touch down itself so there's no second chance - even if the Philae could be righted the screws wouldn't be able to be reused.

  • Voyager2 says:

    Firing of harpoons did not occur, so what is the thing you see below, center to the right of the picture, it looks like a string that anchores the Lander to the rock? or is it just an image effect?

    • TonyR says:

      That's clearly a cable extending into the surface. You can tell by the shadow it's casting.

    • MattR says:

      @Adrian / @PeterK:
      Initial "approach was about 1 m per sec
      First bounce with 38 cm per sec, lasting 111 min resulting in a 1 km "hop" (to "B")
      Second bounce with 3 cm per sec resulting in a 10 (or so) m "hop" (to the crater "rim" between site "B" and "I" which is to the right of "J" in most pictures).

      Bounces "shortened" because of damping by the landing gear

      @Voyager2:
      The "string" is one of the "antennas" (there are two):
      See above link at 20+ and 30+ secs

      And, yes, the harpoons could be fired, but that might result inother jump, to an unknown destination
      And, actually, Philae can "hop" (using its landing gear).

      Absolutely amazing story, big success!

  • Fernando PalopMarro says:

    Great! Proud to be European

    • Adrian says:

      I'm proud that most Europeans don't need to say they are proud to be Europeans when this is a mankind achievement 🙂

  • Cometstalker says:

    Impressive landing manoeuvre, the time between the bounces indicate a huge first jump the second was moderate. The first one hour upwards and then one hour downwards the second about 7 minutes up an down. Not knowing the local gravity is hard to estimate the hight but a 1 m drop takes 80 or so seconds.
    The second drop possibly to an 8 meter elevation but the first jump to impressive over 300 meter altitude. A lot of luck saved this mission outcome and i actually saw on person slapping one hand on the other indicating the bounce. My figures are not accurate but the scale is about right.

  • USA Citizen says:

    This such a great moment for humanity to accomplish such a feat, I have to congratulate all of the European minds that have worked so hard to make this a success! Congrats and great work indeed! I hope this craft is able to provide more scientific answers (and clues) as we turn science fiction into science fact.

  • Jacob Koch says:

    So what will this mission accomplish? It seems pretty exciting and I am just now hearing about it. Very curious and anxious to see what data this produces.

  • Ian f says:

    Wwwwwwwooooooowwwwweeeeeeeeeeeeee I'm really happy for a machine this is going to be legend wait for it dart

  • Taray says:

    ok, so who is taking the video's and pictures at such close range? Comets are traveling at a great speed with some sort of rotation as well right? is there another craft out there taking photo's with such perfect lighting in such dark "Space"? or is it a "Selfie"? I am an enthusiast and I do not mean to sound cynical, but how close is this comet?

  • Cometstalker says:

    Great picture with a lot of totally new items to discuss. Do try to use all tricks in the box to at least get the screws anchored as it seams to be practically without dust layers, its not about drifting away but its essential for some experiments, the harpoons or thruster are not an issue anymore and forget them for a while at least until the screws are in the cork. The drill might help to get some information if handled with caution.
    Anyhow its safe and so far so good, i suppose that this knowledge is essential for the future missions. This glitches might actually turnout to be a positive event like a spoiler.

  • Ian f says:

    Wwwwwwwooooooowwwwweeeeeeeeeeeeee I'm really happy for a machine this is going to be legend wait for it dary

  • Zineb says:

    Congratulations!! Philae!

    One question:

    Rosetta has been travelling for 10 years, it means that all the equipments especially for photo processing and data collecting date back to 10 years, which means that Philae is now operating with a 10 years old tehcnology. My question concerns the impacts of that on the work of Philae. Also, dont you think that you will have "excellent" results using a 10 years old technology? Thanks!!

    Congratulations again!!!

    • Michael says:

      The technology is actually 20 years old, it took 10 years to fly there and 10 years to design and build.

    • Adrian says:

      I think 10 years ago there were already good photo cameras and excelent lenses. But i'm also interested in know specifications of the photo instruments that Philae and Rosetta are carrying.

    • Graham Hall says:

      Yes the technology is even older than 10 years as Rosetta was designed and built long before its launch 10.5 years ago. It was even designed to go to a different comet. On the other hand the cameras would have been state of the art at the time. For the general public the pictures are very important, for the scientists less so - the data from their instruments is much more significant. The pictures help capture the imagination of the public, reams and reams of science data don't.norm

    • MattR says:

      @Zineb:
      Actually, Rosetta took off 10 years ago, but was designed and built about 15 (to 20) years ago.
      Usually all satellites are built with components, which were "cutting edge" 5 to 10 years before launch, because assembly, tests, (re-)assembly, more tests, transportation to launch site are all pretty time consuming.
      Today you could built a better Philae, but it would arrive 15 years from now at the comet. That's simple the way it is.

      Did this timespan have an impact: considering the harpoons and the thruster (to hold Philae down), maybe "yes". Could it be done better: probably "no".

      Consider this: everything worked flawlessly (so far).
      There had to be some problems (after all those years).
      But, there could have been more and more serious problems, though. But there weren't. Great work!

    • logan says:

      Hi Zineb. Endorsing nobody, but quite sure it's the world's best engineering at the time when Philae was build.

    • Andrea says:

      Zineb, the spacecraft was launched 10 years ago but of course it was build before and designed even earlier. This means that Rosetta uses a 15 - 20 years old technology. It looks pretty obvious, doesn't it? If we start to design a new space mission tomorrow morning to be launched in 2025 and maybe used in 2035, which technology would you use? The one of today or the technology of 2035??? 😉

  • Per says:

    My guess is that when the lander bounced the comet rotated and the lander come to a stop against a vertical rock.
    If You look at the image there is a large rock real close and if You look at the white part in the middle to the right it seems as something has hit the rock (probably the lander)

  • rod says:

    there appears to be a cable running into the surface of the comet?

  • Haring says:

    Before of all, congratulations for this extraordinary mission and how you manage information to the public.

    Philae is not anchored?
    It could be better... Since it bounced safely 2 times, it could be an idea to allow him to jump again, after the experiments have been completed...
    Will the harpoon provide enough reaction, if fired (and hopefully NOT hooking), to allow at least a small jump?

  • Vassily says:

    @Zineb: The technology is ten years old but made for space operations, not for Christmas shoppers. Do you honestly believe the cameras for example shoot with 3.2 mp? 🙂

  • Mark says:

    I wonder if the harpoon(s) could be fired to try to get it to bounce to a better location? If it's in shadow, the rechargeable batteries are not going to last long. I don't think it has any thrust mechanisms, does it?

  • Mic says:

    Congratulations to all involved, what a great day for science!!!! Hopefully we gain valuable insight into the universe around us and continue to learn more about who we are and where we came from. You all should be very proud. A lot of things can go wrong over 10 years and the fact that it all came together shows that you worked as a team, solved problems and did it for the greater good of mankind. Well done!!!!!

  • dieblume says:

    Congratulations to everybody involved.
    You are a great example for international cooperation and a reason to continue believing the "european" dream! Thanks for that.
    Always amazing how the deep space is universally fascinating.

  • Trevor says:

    It is supercalifragilisticexpialidocious
    good to be European

  • maher says:

    Based on 10 years back technology one could not expect much things but still considers Great leap ahead..... good job

  • Dan Kitchen says:

    In answer to a few of the questions I these comments, the harpoons can be fired and as far as I'm aware the landing screws can also be used.

    The issue with both of these mechanisms where we are now is that without a means of counteracting the upward force produced by these mechanisms their use could cause Philae to push off of the surface and not come back. Down force would have been provided by the thruster on top of the lander, and would have fired upon first landing to counteract to force of the harpoons and screws. As we saw though this component malfunctioned and is not able to be used causing the current concerns with using these mechanisms to secure the lander.

    At the moment I think gravity is keeping it on or just above the surface. The issue currently is that Philae is obscured partially by shadow and is not receiving enough power to operate once its main battery runs out. Secondly there is a reluctance to deploy certain instruments due to the above mentioned issue with force that cannot be counteracted.

  • 10-yr old technology!
    Hence the telemetry link to Earth of 28Kb/s-1 as reported on the 'Rosetta Operations Update' link.
    Dial-up!

  • logan says:

    "...recorded a rotation around the Z-axis..."

    So it flipped -after all- THOMAS. 😉

    • hank says:

      Rotation around the Z-axis -- around the vertical axis, so not a 'flip'

  • Rocky Rhodes says:

    Just a guess regarding the unusually long first bounce: Philae hits the surface, fires the harpoons, but instead of piercing the surface, they propel the lander a pretty good ways from the comet (near losing it from the comets gravity) but Philae makes it back to the comet with only the last two landings. As far as ten year old technology, it it is not the age of a particular design and technology but the long term reliability of the design and technology.

  • Bud Deihl says:

    Signing, fantastic and astounding considering the computing technology on the board is now over 10 years old.

  • Andrea says:

    Piot, the touchdown was at 15:34 UTC which means 16:34 CET (Central European Time). The data transfer takes ~28 min to be received on the Earth. This means 17:02 CET, when we actually got the touch-down confirmation. No typo 🙂

  • Karl says:

    I think some of the confusion about time between "bounces" may stem from the fact that this blog uses two different time zones ("After touchdown at 15:34 UTC (confirmed at 17:02 CET)") in one statement.
    Minor detail considering this great achievement.

  • Dr Moore says:

    I'm very excited, will not sleep tonight and will eat not one but two packets of M and Ms. Till bedtime I willI run backwards knocking furniture over.

  • Klaus Stadtmüller says:

    Incredible Performance and with its duration of already 25y a very unusual project. Scientifically and technically much more Important than the mission to the Moon.great European achievement!
    Congratulation

  • Cam says:

    The comet does have enough gravitational to keep philae on the surface, the harpoons were precautionary, in fact the gravitational pull of the comet was what allowed philae to land on the comet.

  • Nick says:

    Although any moving attempt might be too risky for the lander, I wonder if by activating the harpoon that is on the air could move it enough - by vibrations - so that the foot steps down.... and again, seems risky.
    Congratulations for the landing!

  • Jon Hingos says:

    Hello all Im wondering if the command centre will try to get the harpoons to fire and anchor the lander,?

  • Jon Hingos says:

    Hello again Its Jonny Im across the pond in usa , You are all AWSOME Great job Mates, BRAVO !

  • Nanci & Richey says:

    Great Job fellow Space adventurers! Info will be BRILLIANT! Tucson L5 Space Society "Since the seventies"

  • Jacob Nielsen says:

    Philae the Jolly Jumper

  • Chris Townsin says:

    Great job guys but when do you think you'll be able to deploy the harpoon and can these be employed to rotate Philae to a better orientation for the solar panels ?

  • Chris Townin says:

    This is a fantastic acheivement in the field of "studying of comets" - well done to the team - I hope that you will inspire a fresh generation of astrophysicists given the media attention generated (my kids are certainly talking about it) , My question/concern relates to the harpoons and their deployment : do you believe that the harpoons can be employed to re-orientate the lander so that the solar panels are positioned more effectively ? Or alternatively, as a colleague has asked, can the lander generate any thrust in it's own right to correct it's current positon? Thanks and good luck!

  • Malcolm Light (Dr) says:

    Philae will be on the comet as it approches the sun and the illumination of the panels should improve by then. Seismic vibrations from gas jets may also change Philae's orientation by then. Can some reserve power be left in the batteries so that the probe can be reawakened when the condtions are more favourable later.

  • hank says:

    If only we knew exactly where the lander is, and

    if only the orbiter had a reflective flat surface and could orient to use such a mirror to direct a sunbeam down into the dark spot to give a little power to the solar cells ...

    or I suppose a nice powerful laser illuminator 🙂

  • K.Kubotera says:

    I am surprised to great technology of ESA. .I hope from japan to be even philae and roseta great success in the future.

  • Kris Jackson says:

    No. The spacecraft is designed to investigate this one body, the comet. It has plenty of work to do where it is.

  • Kowlaski says:

    Tahnks for sharing information...Give Us more data and more pictures ...

Comments are closed.