Where is Philae? When will it wake up?

These are the two most popular questions currently being asked of the mission – especially on our social media channels – and ones that we will try to answer in this post, including inputs from the OSIRIS team, and from the Lander Control Centre at the German Aerospace Center (DLR).

Where is Philae?

Ever since Philae touched down on Comet 67P/Churyumov-Gerasimenko for the final time on 12 November – it is thought to have come into contact with the comet’s surface a total of four times including the final landing – the search has been on to identify it in images. While the CONSERT instrument has helped to narrow down a 350 x 30 m ‘landing strip’ on Comet 67P/C-G’s smaller lobe, a dedicated search in OSIRIS images has so far not been able to confirm the little lander’s final location.

Philae descends to the comet. The timestamp marked on the images are in GMT (onboard spacecraft time). Credits: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA

Click for animation! The timestamp marked on the images are in UT (onboard spacecraft time).

Philae’s descent to the surface, the initial touchdown at Agilkia at 15:34 UT (onboard spacecraft time) and first rebound were well-documented with the OSIRIS narrow-angle camera. The team also identified what they believe to be the lander in a wide-angle shot taken at 17:18 UT above the rim of the large depression – named Hatmehit – on the comet’s small lobe. The image has been used to guide subsequent lander search efforts, and provides the basis for trajectory reconstructions. According to data recorded by Philae’s ROMAP instrument, the lander may have grazed the surface at 16:20 UT – so this image may have captured the result of that encounter.

Philae above the comet?Rosetta’s OSIRIS wide-angle camera captured this view of Comet 67P/Churyumov–Gerasimenko on 12 November 2014 at 17:18 GMT (onboard spacecraft time).  Credits: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA

Philae above the comet? Rosetta’s OSIRIS wide-angle camera captured this view of Comet 67P/Churyumov–Gerasimenko on 12 November 2014 at 17:18 GMT (onboard spacecraft time).

Philae’s onboard data subsequently recorded the next touchdown at 17:25 UT and its final touchdown at 17:32 UT, at a site that has now been named “Abydos” (the first touchdown site remains as Agilkia). Images sent back by the CIVA imager onboard the lander and subsequent reconstructions are providing clues as to the nature of the landing site, but a visual confirmation is still required to confirm its location.

Follow-up dedicated OSIRIS imaging campaigns that took place in late November and December from distances of 30 and 20 km from the centre of the comet (about 28 and 18 km from the surface, respectively) have not been successful in locating the lander. The campaigns specifically targeted the times that the lander would be illuminated – it is illuminated approximately 1.3 hours per comet revolution – and that Rosetta had the correct orbital position to be able to image it. However, the cameras were looking into long cast shadows from Rosetta’s terminator orbit, perpendicular to the Sun direction, which does not provide the optimum conditions for detecting the lander.

It is also important to note that Rosetta’s trajectory immediately following Philae’s touchdown allowed for good viewing conditions at the original landing site. Now that Rosetta has moved to a different orbit, and is further away from the comet, the chances of observing the lander are less (watch this video for a recap of the different trajectories following the landing).

The image below is an example of the images being used to search for the lander; it is a slightly cropped 2 x 2 mosaic taken by the OSIRIS narrow-angle camera on 13 December 2014 from a distance of about 20 km to the centre of the comet. For the 20 km imaging run 18 sets of two images were taken – one each with orange and blue filters to take advantage of the reflection of the lander solar panels, which differ compared to the cometary environment. The images were taken in the 2 x 2 rasters to ensure good surface coverage. The lander, about 1 metre across – the size of a household washing machine – would measure only about three pixels across in these images.

“We’re looking – by eye – for a set of three spots that correspond to the lander,” says OSIRIS principal investigator Holger Sierks from the Max Planck Institute for Solar System Research (MPS) in Germany. “The problem is that sets of three spots are very common all over the comet nucleus; Hatmehit and the area around its rim where we’re looking is full of boulders and we have identified several sets of three spots.”

Lander search area. The image is a 2 x 2 mosaic comprising OSIRIS narrow-angle camera images taken on 13 December 2014 from a distance of about 20 km to the centre of the comet.Credits: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA

Lander search area. The image is a 2 x 2 mosaic comprising OSIRIS narrow-angle camera images taken on 13 December 2014 from a distance of about 20 km to the centre of the comet. Credits: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA

Although Rosetta is flying to within 6 km of the comet’s surface on 14 February, the planned trajectory foresees the closest approach on the lower part of the larger comet lobe (although the trajectory also takes Rosetta over the first touchdown point). This trajectory is planned such that the Sun will be directly behind the spacecraft, allowing the acquisition of shadow-free images. The close flyby will also allow the suite of science instruments on the orbiter to take spectra of the surface with unprecedented resolution and to directly sample the very innermost regions of the cometary coma in order to learn more about how the comet’s characteristic coma and tail develop.

“Rosetta’s busy science schedule is planned several months in advance, so a dedicated Philae search campaign was not built into the plan for the close flyby,” says ESA’s Rosetta project scientist Matt Taylor. “We’ll be focusing on “co-riding” observations from now on, that is, we won’t be changing the trajectory of Rosetta to specifically fly over the predicted landing zone in a dedicated search, but we can modify the spacecraft pointing and/or command images to be taken of the region if we’re flying close to the region and the science operations timeline allows.”

“After the flyby we’ll be much further away from the comet again, so are unlikely to have the opportunity for another dedicated lander search until later in the mission, maybe even next year,” adds ESA’s Rosetta mission manager Fred Jansen. “But the location of Philae is not required to be able to operate it, and neither does it need to be awake for us to find it.”


When will Philae wake up?


The likely orientation of Philae, shown in a visualisation of a topographic model of the comet's surface. Credits: ESA/Rosetta/Philae/CNES/FD

For those of you who followed the wake-up of Rosetta, you will know that it is not simply a case of switch on and get back to the science right away. The same goes for Philae.

At the original landing site, Philae was expected to receive around 6.5 hours of illumination per 12.4 hour comet day, with temperatures becoming too high by March 2015 to enable continued operations. Now, at its new location, the illumination is just 1.3 hours.

“Now we need the extra solar illumination provided by the comet’s closer proximity to the Sun by that time in order to bring the lander back to life,” says DLR’s Lander Project Manager Stephan Ulamec.

In fact, even by May, the Sun inclination will be such that it will be directly overhead of the predicted landing zone, although the lander’s orientation is such that it won’t be able to make full use of the maximum illumination on offer.

As for the process of wake up, and assuming Philae survived the low temperatures in its new residence, the earliest that the lander team expect it to be warm enough to boot up is in late March. But it will likely be May or June before there is enough solar illumination to use its transmitter, and to re-establish a communications link with Rosetta – the lander needs about 17 Watts to wake up and say “hello”.

Furthermore, the orbiter also has to be commanded to listen for Philae’s “I’m awake” signal, and be in a good position relative to the landing site to pick up the signal – although it can be up to 200 km away from the comet. It will be longer still before the battery is fully charged and Philae is ready to do science again, but that means there is a chance it will have a ringside seat for perihelion.

“We are already discussing and preparing which instruments should be operated for how long,” adds Stephan.

But even if Philae doesn’t wake up, it’s important to remember that it already completed its first science sequence on the comet, unexpectedly providing information from multiple locations on 67P/C-G.

Meanwhile Rosetta will continue to follow the comet on its orbit around the Sun and as it heads back towards the outer Solar System.




  • Bonjour,

    Y a t il de la glycine sur la comète Tchouri ?
    Peut on extrapoler la trajectoire de la comète et prévoir si elle va atterrir sur Terre, dans un Océan ou bien ailleurs ?
    Ya t il une réaction de fusion froide dans la comète qui lui permet d'éjecter de l'eau lourde ?
    J. Puyuelo

    • Gerald says:


      les données d'instrument Ptolémy sont en train d'être analysées. On a mesuré beaucoup de masses moléulaire, C'est pourquoi l'analyse est très complexe, et il va prendre un peu plus de temps jusque les résultats vont être publiés.

      La trajectoire de la comète dans ce moment a un perihélion (le point plus proche du sol) entre l'orbit de la Terre et du Mars, sans danger d'une collision avec la Terre.
      La comète pouvait rencontrer Jupiter et changer l'orbit dans la future. Mais il est très difficile de prévoir la trajèctoire après une possible rencontre. La probabilité d'une collsion avec la Terre est négigible dans ce moment.

      L'énergie des proton du vent solaire est trop bas pour une fusion. Mais il y a des particules chargées d'origine galactique avec une énergie suffisante pour permettre des réactions nucléaires. La fréquence de cette sorte de réactions est très bas, trop bas pour être considerée rélévant dans des périodes courtes.
      Mais il y a probablement des traces de l'eau lourde (D2O) á la comète. Plus fréquent est de l'eau semi-lourde (HDO).
      Fusion froid n'éxiste probablement pas, sauf peut-être des réactions rare avec neutrons.

  • cosmo says:

    The secondary battery of the lander consists of Li-Ion cells. Li-Ion cells are very sensitive and undervoltage might cause cell damage. Self-discharge is inevitable. Is there some concern about this issue?

  • Hello, is there any way to contact who's working on the task of finding Philae?
    I would like to know if it' s possible to submit an idea I have but I cannot find anywhere more information on contacting. Please let me know, even by email.

  • Guili says:

    It is not true that Philae completed its first science sequence. The drilling didn't take place, for instance. Also, we read in this blog that without having the proper location of Philae, interpretations of some Concert data was not possible. Let's not rewrite history there. Philae was a success but some experiments of the FSS are missing results.

  • Ana says:

    Thanks, Emily. Your article was of great help for me. It was so strange that nobody could locate Philae so far. I was starting to think that they don't reveal lander's position for a hidden reason. Now I understand how things really are and technology limits. Even without Philae, everything posted on this site is amazing.

    Best wishes to you and all Rosetta team!

  • gravelinspector says:

    The question occurs - has imagery been captured to make 3d or anaglyphic presentations of the surface shape and slopes to constrain possible locations?

  • logan says:

    Thanks Emily, and OSIRIS team for a well detailed photo.

  • logan says:

    With this dust/gas radio, at perihelion we should be able to see some 'mud' sneakingly trying to hide, down there 🙂

  • Daniel says:

    Truly a difficult job to make a positive identification Philae from such images With the larger set of images with slightly different timings you might be able to rule out quite a few potential spots, but maybe not enough. I don't however understand why the red ellipse isn't the same area as the improved CONSERT estimation,.

    Either way, new ORISIS images are always welcome and the OSIRIS WAC picture of Philae hovering close to where it finally landed is an extra bonus.

  • Dilip Sharan says:

    Like the analysis. Hope Philae will awaken in time to do more great science around perihelion. Another question though. What is the long term plan for Rosetta? Will it be left in permanent orbit of 67P? How long can it survive, especially further from the Sun? What is the fuel position?

    • emily says:

      Hi, and sorry for delay in replying. Rosetta's long term plan is to study the comet as we continue on to perihelion (closest approach to the Sun along its orbit) in August, and then watch how the activity subsides again towards the end of 2015. It has already moved out of a bound approx 30 km orbit around the comet and is now making a series of flybys at a range of distances from the comet (see here for more info: http://www.esa.int/Our_Activities/Space_Science/Rosetta/Rosetta_swoops_in_for_a_close_encounter
      When Rosetta was previously at its furthest from the Sun (close to the orbit of Jupiter) it was put into hibernation as there was not enough power to operate it (it was in hibernation from June 2011 to Jan 2014). I do not know the fuel situation, but it is a topic of discussion as to how long the orbiter may be able to operate into next year.
      Hope that answers your questions!

  • Robin Sherman says:


    What a glorious image. Big THANK YOU to Holger and the OSIRIS team for sharing this image. There is so much to drool over in this image, but I guess the location of Philae is of most import. As I have already nailed my flag to the mast for Philae's location, the first place I looked was where I thought Philae landed. There is a fair bit of explanation involved to explain my conclusions, so I apologise in advance for the length of this post.

    The red ellipse on the image is the suggested search area, but my interpretation of the latest CONSERT search area has it further down the cliff, below the level of the two bumps in a horizontal band across the width and a bit more of the cliffs below the bumps. So the first image below is a context image to show this and the area of the second close up image. This evidence is not just, "its three blobs that look like Philae", I have indicated possible matches to the surrounding topology seen in the CIVAS images from Philae.


    No doubt others will disagree with this interpretation, and point out that the OSIRIS team has more exact information. However for all the 3 CONSERT defined areas we have seen, there has been a corollary that the shape model used is not reliable in this area because of the poor illumination conditions. The second suggested area even gave two different possible areas. So a discrepancy of a few tens of metres in interpretations is, in my view, insufficient to rule out areas adjacent to the red ellipse.

    For the close up image below I have scaled up the image, to make it less blocky. My tools are limited so others should be able to do better. As the post above says Philae only occupies a few pixels in this image so the surrounding formations must be attributable to those seen in the CIVAS images, remembering Philae's main body has rotated 36 degrees since those images were taken.


    So what can be said about this predicament that Philae finds herself in. It appears she is not vertical and pointing at an angle, hence one shot from the front left camera of mostly "sky". If my interpretation of the tiny blobs as Philae's shiny feet is correct, the front right is resting on a boulder and the front left appears to be in the air, as originally suggested by the Lander Team, but it may also be in contact with the surface hidden by the shadows. The back foot can not be seen at all, one, because it is in shadow and two, from this viewpoint the body would probably hide it. We know it is almost completely buried anyway so would not reflect anything like the amount of light the other two do.

    Philae also appears to be suspended some way from the bottom of the crevice, something that has been proposed as being fairly certain and would explain why the drill did not return any solid sample. The MUPUS probe extends some distance from the back of Philae and since the back foot is in solid contact with the surface behind Philae, it can be supposed that that extension was enough to make contact with the same back surface of the alcove.

    To the right of the three blobs is where Perihelion Cliff should be. In the CIVAS image this is seen as two overlapping thin sheets of material with a gap at the bottom through which a bright roughly round boulder can be seen, approximately along the line of the landing gear leg. This boulder and the overlapping sheets, can be seen in this image. The bright rock we saw in the right side CIVAS images can also be seen, the shape matching quite well to the brightest areas in the CIVAS image.

    The back left CIVAS image was very dark , but after processing it reveals two peaks of material behind Philae, with their forward edges and tops appearing slightly brighter. These can be seen too, the slightly better angle of illumination seems to fully catch the tops of these peaks. The nearest peak to Philae in the CIVAS image has a hole through the shoulder at the back of it, indicating erosion has taken place and therefore sunlight does reach this point in considerable amounts at some point during the comet's orbit. This is good news for Philae as she currently stands between the entrance of the alcove and this pair of peaks and should therefore have significant amounts of sunlight available at some point later in the comet year, as predicted by the Lander Team.

    So if one concedes that the search area is not that well matched to the actual shape of the comet, a very good case can be made for this being the location of Philae. Add this to the similar context evidence seen in the NAVCAM images used in my original post in late November, I see no reason to change my opinion that this is where Philae is located.

    I would add this time though, these crevice formations are very common in this area of the comet and so there may be others hidden in the shadows of the two bumps that could also be a candidate, presenting similar topology as evidence. I say again this is my interpretation, and should not be taken as a definitive location for Philae, others are welcome to disagree and hopefully will have found an even better candidate.

    I will scour the rest of this wonderful image for other nuggets to comment on in later posts.

    • Robin Sherman says:

      I have revised my guesstimated, artist's impression of Phillae's journey across 67P. They are not calculated or intended to be to scale, just as a visualisation and understanding aid. I have also used my own final landing point from above, so again please don't take this as fact. It's just to chart the progress of the situation as I see it.

      The first image uses the OSIRIS WAC image that has the speck that probably is Phillae above the Hatmehit depression rim wall. The point that Phillae makes a one foot contact with the rim wall still has to be a guess, but various simulations using more sophisticated tools and data place it in this general area. The green trajectory passes right through the speck so it can no longer be seen, but I have circled it in yellow in addition to the original red crosshairs.


      The second image uses the OSIRIS NAC image of the lander search area. I have marked a number of points of significance along with the times they occurred. The trajectory of the second bounce is in red. Phyla is only travelling at about 10cm/s during this bounce and it only lasts 7 minutes. The altitude data from Phillae shows that she is still above the surface at final touchdown, consistent with being "wedged" several metres from the bottom of the crevice.


      The third image is just a close up of the landing area. I have marked Matthias Malmer's "Glint" that he picked out from the NAVCAM movie and suspected was Philae. Other images showed it was possibly an exposed icy boulder and this OSIRIS image shows that to be the case. It is however very close to my proposed spot. Given Matthias's expertise, if he thought Phillae could have reached that point, I see no reason not to think my spot is very possible too.


      I haven't even started on the details of all the different terrains. Would an area covered in "Goosebumps" be said to contain a flock of "Goosebumps", or a clutch of "Dinosaur Eggs"? 😉

      • Daniel says:

        I also think that the red ellipse isn't correct with respect to the latest CONSERT area. Your attempt isn't exactly how I'd put it either, but then again, the shape model used by CONSERT might not be 100% exact either plus it depends on how well constrained Rosettas position was.

        You've consistently have put Philae at roughly the position you've indicated, so I will give you some critique about it and hopefully you don't mind. If I've made any errors in my assumptions then please point them out. Let's ignore that your position is outside the CONSERT area according to me. Then one of my main objections is the shadows on Philae.

        The +X foot (i.e. the one seen in the CIVA 3 image or what you call the front right foot) has shadows coming almost exactly from the left and say ~45 degrees from above (the 45 degree value is a lot more uncertain, it's just a quick guess). The +Y foot (i.e. the one seen in the CIVA 1 image or what you call the left front foot) has the sun coming from the front and a bit to the right, how high is difficult to determine. Either way, this puts constraint on the orientation of the lander with respect to the sun. The OSIRIS images are supposed to have been taken during the time Philae is lit, in other words knowing the direction of the sun in the OSIRIS images then determines what kind of orientation Philae has in the OSIRIS raster. The sun is coming from the top of the OSIRIS image, disregarding how high it is.
        Now combine this information with what you can see in the CIVA panorama, most importantly that nothing is seen in the CIVA 2 image.
        The gist of it is that the in the OSIRIS image the +Y foot is most likely "above" the body and to the right while the +X foot is most likely "below" the body and to the right.

        Well, that was a bit long winded, this is how I think Philae should look like in the OSIRIS image http://i.imgur.com/icrmEtf.png (note, variations definitely possible). Your supposed Philae doesn't fit that mould.

        The main uncertainties in my method is whether my rough sun directions are correct, I simply guessed a "good enough" after all. I'm also assuming that the OSIRIS image is taken on the same time of the comet day as the CIVA images.

        • Robin Sherman says:

          Hi Daniel. Thank you for your analysis and images. As you rightly say the sun is "above" Philae in the position I have indicated and your pictorial representation clearly shows this correctly within the limitations of the information available. I do however question your interpretation of this being the view from Rosetta. Rosetta is in orbit along the terminator of the comet and must therefore be looking at Phillae from a lower angle than this. Looking at the OSIRIS lander search image , a line from top to bottom through the image passes through the centre of the red ellipse and this marks the point where Rosetta is perpendicular to the surface. This means Phillae's position is slightly to the side of a direct view. Therefore I would interpret Rosetta's view as being from between 3 and 4 O'Clock on your images and therefore be very similar to the view in the OSIRIS image.

          Your proviso about the times when the images were taken is still valid, but my interpretation is that your analysis is more evidence for this being the correct position of Phillae, though that proviso means it can in no way be conclusive.

          With regard to the CONSERT search area, I would refer you to the image in Kasuha's post below and this image I posted previously. I used the larger ellipse in the context image above to match the search area being used by the OSIRIS team which is clearly a version of the second CONSERT defined search area, not the the more recent and much smaller third version.


          Thanks for taking the time to explain your doubts. I am not sure you will be convinced by my conclusions, these 3D interpretations from 2D images are never easy. I just hope those in the science team consider there is enough of a possibility to model the area in some detail to see if it is a possible match. Projections of what Phillae can see from this position are possible. Alex K. contacted me via Flickr with these images.



          • Daniel says:

            You could probably do a whole lot more in 3d with a better model of the comet and more work, but here I'm using the released shaped model of 67p along with an gigantic Philae: http://i.imgur.com/8tvw3z0.png
            I would use the model Malmer made but my computer is ancient and it chokes on it. Anyway, it should be very roughly the same view as the OSIRIS one. The reason the area where Philae should be looks so different is simply because the model isn't good enough. It is very smooth there and lacks the hard edges, so you don't get the same darkness and shadows. But it shows once again how I would imagine Philae is oriented, the shadows on its legs are roughly correct.
            Looking at Philae from a lower angle doesn't change enough (unless I miss interpret how you mean). I simply don't see how the feet can be at the positions you indicate relative to the body.

            This on the other hand is my interpretation of the CONSERT area: http://i.imgur.com/wI5FafD.png
            I've highlighted certain features that I've used to attempt to identify it. The yellow hill/ridge and blue hill being the main identifiers. The purple area is where your Philae location is. I just can't I am willing to be proven wrong as how far to the left the CONSERT area reaches, but I'm very certain that https://www.flickr.com/photos/124013840@N06/16058382452/ doesn't go far enough to the right. I would be very surprised if I've misidentified the blue hill in my highlighting which thus constraints it on the right side.

            But as you said, trying to make the conversion between 3d to 2d and back again can be difficult. Someone with a bit beefier computer, a better comet model and some more effort into making sure the position of Rosetta and the sun is correct could probably do a whole lot better than I've done.

  • omero says:

    Hello Emily,
    First of all, thank you indeed for the update on how things are with Philae! Long awaited news indeed.
    Would be asking too much for a version of the fantastic OSIRIS image without the red ellipse? In any case, keep up with all the exciting blog entries!

  • Kasuha says:

    Thank you for this update, much appreciated!
    Now I understand why is it so hard to find Philae and why the search wasn't successful so far.
    I wish you'll succeed finding it before it reawakens.

    I have of course also picked my personal favorite for Philae in the image you provided, although I'm pretty sure that spot was already investigated very thoroughly and most likely excluded based on other images and information you didn't share.


  • masanori says:

    Thank you very much Emily and all in the Blog team! All I am hoping about Philae for now is that he will wake up again and delivers more science, whenever but hopefully when close to perihelion.

    One question, please.

    I think I heard Prof Bibring said in AGU video that the illumination hour on Philae in coming months is going to be 4.33 hours. I think maybe I missed some words which were attached to this. But now I love to know what data/calculation/estimation ends up with 1.3 hours and what ends up with 4.33 hours, what is the difference of calculation/estimation between 1,3 hours & 4.33 hours, please. Thank you very much!

  • Nick Wyver says:

    I don't suppose you have any images of the landing site area from before the landing so you can do a flicker comparison.

  • Marco says:

    Let me get this straight. Agilkia is in the region of Ma'at, Abydos is in Bastet, and Philae flew over Hatmehit to get there. Philae is pretty close to the cliff edges of Hatmehit. I was just wondering, since Philae's orientation is known, if the "perihelion cliff" or other landmarks visible from Philae would be the peaks on the edge of Hatmehit?

  • Christoph says:

    Thanks for keeping us informed.
    Why do you believe the small bright spot above the crater rim/the horizon on the image of 12 November 2014, 17:18 GMT to be Philae and not some bolder or peak of the comet topping it's surrounding and illuminated by the setting sun? (Such light spots in a dark environment can be found on many images, e.g. ESA_Rosetta_NAVCAM_141202_A.jpg).
    Finally let me wish the Rosetta mission and team a happy and successful year 2015!

  • Sérgio Muraro says:

    My guess about Philae: https://flic.kr/ps/2ZHhyV

  • Cometstalker says:

    It would be nice if the lander could be repositioned with means of the flywheel and the electro mechanical suspension in the landing gear once the batteries are up to this maneuver. Another 50m jump is no risk once the flight team has a go for this kind of project.

  • flug says:

    I've just released updated videos showing a visualization of the best known trajectory for Philae from before touchdown to final resting place, using Matthias Malmer's 3D model of 67P.

    Overflight/overview of trajectory:


    Philae's first-person viewpoint of the flight:


    Extended discussion of the visualizations, updates and reasons for updating, sources, etc., here:


  • Michael B says:

    Once Philae has enough power, maybe Rosetta could find it with a "reverse GPS" technique—with (at least three) "virtual Rosettas" in orbit? Have Philae send a signal at the exact same time every complete comet rotation. If Rosetta could be in slightly different positions when each "daily signal" is sent, then trilateration of Philae's signal should narrow down its position. Just a thought. Good luck!

  • Amateur Astronomer says:

    Could this be the Philae Lander? The shape looks somehow similar. Please verify.


  • Kasuha says:

    I remembered an updated Philae position estimate was presented by the CONSERT team on the AGU meeting:
    But I am having major problems identifying features from that slide on the photo. Assuming the hill in the middle of the ellipse is the bump near the right end of the estimated position area, my guess would be actually quite close to the center of the estimate.

  • Robin Sherman says:

    Michael B. I think we can assume this was part of the information that went into refining the search area for Phillae, along with flight simulations and the CONSERT data, which in effect did the same thing, but using radio waves capable of passing through the comet.

    I have been studying the lovely OSIRIS image further and have picked out 4 sections with terrain and features of interest. In order to keep this post shorter I have added my comments in the descriptions accompanying the images.





  • Seymour B. says:

    If Philae is receiving 1.5 hours of sunlight on it's solar panels per comet day, wouldn't 4 days equal the normal full charge it would receive if it didn't bounce?

    • Gerald says:

      Yes, taken this aspect alone,
      But before charging Philae needs to be warmed up. The 1.5 hours at 3 a.u. aren't sufficient for that.

    • Kasuha says:

      No, because to charge its batteries, Philae has to warm them up first. The lander's temperature is somewhere near -150 degrees Celsius and the battery can't be charged at that temperature. So every time there's sun shining on Philae, it starts warming the battery up first and only when (if) it's warm enough it can start actually charging it.
      Also according to info I found - if Philae's battery even tries to keep any charge through freezing period - significant part of that charge is said to be lost. But since freezing a charged battery may result in some permanent damage, it's a question if Philae's battery isn't wired to keep itself warm as long as there is any charge in it instead. That would mean the charging process starts from scratch every cometary day.

    • Daniel says:

      First of it depends on how much of the solar panels are reached by sunlight during those 1,5 hours, Philae is only partially illuminated during that time. Secondly Philae has to heat its batteries to a sufficient temperature before they can be charged, so you could imagine those 1,5 hours going to booting and trying to warm up rather than ever getting to actually start charging them. Then the rest of the comet day that it spends in darkness cools it back down again.

  • Wendy says:

    How does one contact the ESA Rosetta mission team directly regarding the possible location of Philae please, I think I may have found something interesting within your red circled image that you may want to investigate further with more suitable imaging enhancement?

  • mm says:

    Ammm isn't Phillae just that bright little light next to that red circle? 🙂

  • marcoone says:

    for the reasons I have already explained prefer indicate how can position the base of the cliff in Hatmheit

    I start from the concept that during a rebound, the angle of entry and exit are equal;
    I draw to the ground position of Philae during the flight;
    at this point I cleaned the direction from heights and perspectives

    I do not think that the point marked with a red cross in the photo of 12novembre h17.18 both Philae. It could be a peak illuminated by the Sun as seen grazing in other photographs
    also has a height that would not touch the ground at 17.25 (7min)
    Stumble instead a particular abnormal albedo (blue square)

    This hypothesis is also a hope because if it was not stopped by the cliff is likely that the conservation of motion and the center of gravity of the comet as they have brought in the neck, until Hapi

  • masanori says:

    So sorry for such a stupid idea from me.

    But if Rosetta Mission team/ESA don't have time to think about #WakeUpPhilae competition, how about this one??

    Submit in a form of picture or video, clearly stating the date AND time that Philae will wake up at. One submission per person. Deadline is at 6am UTC on 28th March 2015 (Too late??). Once or if Philae wakes up, a prize goes to a person who submitted a time which is the closest to the actual wake-up time among all participants. Personally I hope the prize is the polo shirt of Rosetta Mission.....

    Hmmmm... Some kind of twist lacks....

    Anyway, then I would like to submit with 9th May 8:20am UTC!!

  • Bucshot says:

    Didn't the probe have a tether on the anchoring system? If so could you set the anchor and play out the tether to maybe a different location? With that being said the same process could be use to move the probe using the roll and pitch of the comet? This all depends on if there is a tether on the anchor and how long the line is.

  • kai says:

    Since the comet is sputtering off material all the time and this presumably will increase in intensity as it gets closer to the Sun, is there any concern that Philae might get "pushed off" the comet?

  • Johannes says:

    I may give my suggestion, too. Seam to be a little bit to obvious, but it very looks like the probe.


    Do I get a present now?

  • Vi says:

    Isn't there the risk of Philae to be covered by mud once the comet gets nearer to the sun?

  • Lcagee says:

    If we know the exact times of the touchdowns (3 or 4), the mass of 67p, the mass of the lander, the initial angular momentum of the lander, the change in spin rates in the x y and z axis after each bounce, and the distance to the center of gravity at the time of the first bounce, the rotational rate of 67p, the relative velocity of the lander in each axis, the relative velocity of the surface of 67 p in each axis at the time of touchdown, can we calculate an exact path? The change in the vector should be calculable based upon the change in spin on each axis.

    Also, do we know if the spikes fired? That would alter the calculations.

  • Marco says:

    Maybe Philae?
    Look at the center of this image, slightly right and down:



    • marcoone says:

      This is strikingly similar to a vehicle with three legs Marco.
      The impression that the raking light steps under the vehicle is extraordinary!
      But there are things that do not coincide with be Philae:
      - If I'm not mistaken calculations, with a scale image of 0.9m / pix, the distance between the feet would be about 20m
      - Is perfectly lit (the team says that He receives light for a short time)
      - The site does not match the landscape that Philae photographed around him
      - Is very far from the point estimated to be rather

      I have two explanations for this:
      - in Space contrasts are very strong and the lights and shadows do tricks at times;
      on the moon, near Vallis Alpes, I thought I had discovered a bridge instead there:
      - Someone landed on Comet before Philae :-))

  • Igor Baldachini says:

    What do you think about object in yellow circle in this image?


  • Daniel says:

    Why Philae was not executed with a Radionuklid battery to make it indipendend from the sun. I mean it was to expect that it may will land in the shaddow!

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