CometWatch – 9 August

Rosetta navigation camera (NAVCAM) image taken on 9 August 2014 at about 99 km from comet 67P/C-G.

View and download image here.


Full-frame NAVCAM image taken on 9 August 2014 from a distance of about 99 km from comet 67P/Churyumov-Gerasimenko. Credits: ESA/Rosetta/NAVCAM



  • marcello says:

    When the Philae’s Landing?

    • emily says:

      The working date is 11 November but this won’t be confirmed until a landing site and the flight path has been determined.

  • Solon says:

    What is this object made of? Densities, from Wikipedia:
    Comet 67P/C-G
    102±9 kg/m³

    2648 kg/m3

    999.9720 kg/m3

    Ice is about 90% the weight of water. IS it hollow then?

    • Mark McCaughrean says:

      There are quite a range of numbers out there for the density of 67P/C-G based on previous studies, i.e. before Rosetta arrived, but all are less than the density of water.

      Definitive mean density values will be available soon, once Rosetta has measured the mass and overall volume of the comet.

      But the general thinking is that comet’s are rather loosely-packed, porous structures, as the self-gravity is not strong enough to make the compact. So, not hollow, but porous.

  • Paul says:

    Wonderful pictures!
    But there much better pictures from the Narrow Angle Camera. These better pictures are lacking for quite some time now.

    So it is time to show NAC pictures high res…. The world likes to see the comet on more detail!
    Thanks for your help

    • Mark McCaughrean says:

      Thanks for the interest. We’ll be posting more from NAC when we get them from the external OSIRIS science team. They’re currently very busy, working hard to put maps and models of the comet together to help with landing site selection, a process that has to happen very quickly now. Everyone’s concentrating on that mission-critical part …

      Hopefully we’ll have some soon, but in the meantime, we’ll continue to post images from NAVCAM daily.

      • Dave Harvey says:

        There would be virtually no work required at all to publish them here if they simply posted the “raw” images! I’m sorry, but the excuses for the “mine, all mine” approach to OUR data are becoming increasingly ridiculous. I have put this into the political realm now, and once the UK parliament is back in session, my MP will be asking the Science Minister to make UK contributions to ESA projects conditional on removal of the “proprietary period”….. I ask all others interested in science for all (as opposed to personal glory for a few) to make similar moves in their own countries.

        Of course – based on past experiences of this blog, I challenge the moderators not to censor this comment!

  • Birgit Hofmann says:

    Oops !
    Tschuri is bizarrely shaped today…..

  • Tapio Ahonen says:

    Beautiful, just beautiful!!

  • CRT says:



  • Andrew R Brown says:

    Another fantastic image.

    The slight increase in distance, is due to the completion of the first ‘leg’ of the first so called Pyramid Orbit, which really is a Tetrahedron Orbit. Rosetta will start closing in again, from a different angle.

    There are more boulders visible both on the head and on the ‘chest’ of the large lobe.

    Thank You very much Claudia for giving up some time on your weekend to provide this amazing update for us. 🙂

    Andrew R Brown.

  • Dave Robinson says:

    Why are so few images being revealed to the taxpaying public who pay ESA’s bills? I watched man’s first landing on the moon LIVE, the moon-buggy’s ride across the lunar surface LIVE, etc.
    ESA should provide similar facilities to its sponsors (aka taxpayers).
    Drip-feeding the occasional image is simply not enough! They do not belong to ESA scientists, personally, and they should not keep them for themselves.

    • emily says:

      Hi Dave, we are very happy to be able to share daily images of the comet – you can find them under “CometWatch” if you missed some of the previous publications over the last few weeks.
      Please also see Mark’s comment above.

    • raymundo dionicio says:

      …”moon LIVE”…



      This is not Ok,
      so please delete me if offend some one…

      This is big science,
      not big muscle showing.

    • Mark McCaughrean says:

      There’s a key misunderstanding here: Rosetta is currently just over 400 million kilometres from the Earth, compared to the 400,000 km distance of the Moon from us. That’s 1,000 times further away.

      Thus all other things being equal, the signals arriving from Rosetta would be 1,000,000 times weaker than a mission on the Moon, making it impossible receive any kind of “real time TV” signals.

      As a previous blog article ( explained, we’re currently able to receive data from Rosetta at roughly 46 kilobits per second.

      A 2048 x 2048 pixel OSIRIS NAC image is very roughly equivalent to 64 megabits, so would take roughly 1,400 seconds, almost half an hour, to be transmitted to ground. NAVCAM is “only” 1024 x 1024 pixels, but the same constraints apply. So “live TV” from Rosetta is just not possible.

      On top of which, there are 10 other instruments on Rosetta which also need spacecraft power, as well bandwidth to download their data, so the cameras are not always on.

      Hope that provides a little more background to the technical constraints involved in taking images with Rosetta and getting them down to the ground.

      • Dave Harvey says:

        Are you saying that you don’t even use lossless compression? JPEG lossless (or JPEG-LS or even zip!) should easily manage 2-3:1 on these images, so that should cut the download time to about 10-15 minutes!

  • Haerwe says:

    Max Planck Institut Sonnenforschung Germany is the PI / OSIRIS Experiment. From US sources I learned that the OSIRIS PI prior to Mister Sierks withheld the OSIRIS pictures of the Rosetta Mars flyby 2007 for more than FIVE YEARS.
    Based on the facts(above) : Are we to expect this as the valid MPS/MPG information policy for the 67P/CG mission.

    While ESA states on one of their Blogs:
    This blog is operated by the European Space Agency (ESA) as an unofficial and in-depth source of information for anyone interested in the Rosetta mission.

    It is updated by editors from the ESA Space Science and ESA Human Spaceflight & Operations communications teams with input from Rosetta scientists and engineers.

    The team will certainly do their best to get you the latest information on the wake up of Rosetta on 20 January 2014, and throughout the entire mission as the spacecraft reaches, orbits and deploys a lander onto comet 67P/Churyumov-Gerasimenko.

  • kees says:

    how about boulders flying in the near distance of rosetta ?
    Are they detected and mapped?
    Seems to me this comet is an collection of frosen together
    boulders of all kinds there print leaving when dewing off the comet

  • raymundo dionicio says:

    That crater
    in the front of the neck
    of ET/Duck
    is amazing.

    And considering its density
    and supposed lack of compactness
    then ET/Duck may indeed
    will have her neck broken by the su

  • raymundo dionicio says:

    Some kind of
    extremely “puffy” snow?

  • raymundo dionicio says:

    Here is my first model
    of the “fluffy” layers:

    On original attachment
    some kind of snowy individual crystals.

    The ages turning it to
    something like polystyrene foam.

    The sun spectra heating
    the first surface meters.

    The porus growing bigger
    (and hexagonal) toward the surface.

    • raymundo dionicio says:

      This model could explain
      the very low reflectivity.

    • raymundo dionicio says:

      This model
      would make a sun orbiting comet
      into a dust catcher at aphelion
      and a dust thrower at perihelion.

Comments are closed.