Last NAVCAM archive release

The last batch of NAVCAM images taken by Rosetta during the final month of its incredible mission at Comet 67P/Churyumov-Gerasimenko have been released to the Archive Image Browser.

navcamfinal

The image set covers the period 2-30 September when the spacecraft was on elliptical orbits that sometimes brought it to within 2 km of the comet’s surface (watch this video for a reminder of Rosetta’s ‘end of mission’ orbits).

The archive release also includes the final five NAVCAM images that were published on 30 September, taken shortly after the spacecraft’s collision manoeuvre was executed on 29 September.

The new image sets can be found in folders MTP034 and MTP035.

Comments

8 Comments

  • Marco Parigi says:

    Hi Emily,

    Any word on the next OSIRIS release? I was looking forward to the perihelion ones.

  • James Poynton says:

    Looking at the photos it appears some areas show rock with stratification that to me doesn’t appear consistent with the size of the body. I would have expected an object would have needed to be much larger to have the geological processes to cause this. This makes me think this is a fragment of a large body thrown off at the time of an impact, which has then gone ahead and accumulated more dust and ice to become the body it is now.

    • Gerald says:

      A large body wouldn’t have allowed for the low bulk density.
      Strata may have formed by slow grain settlement of fluctuating grain frequency.

    • ianw16 says:

      @ James,
      You have to be careful of the use of words like “rock” and “geological”.
      It isn’t rock. The processes at work aren’t really analogous to what we see on Earth, except maybe landslides. You have a highly porous body, of very low density, with subsurface ice, some of which is more volatile than others. Some areas will have more ice than others areas. The hemispheres experience different insolation in their respective ‘summers’.
      You also have to factor in a changing orbital history.

      In short, what common sense tells us, based on our experiences on Earth, isn’t much use on a comet.

      In any case, it’s hard to envisage how an impact of a meteorite or asteroid would ‘throw off’ such a large chunk. The parent body, by definition, would have had to be a comet, otherwise 67P wouldn’t be a comet! If the parent body was a planet, then how does that fit with the properties of 67P – i.e. not being at all like a rock?
      We have plenty of large bits of rock in the solar system, some of which may well have once been part of a larger body – they are called asteroids and meteors. They aren’t at all like comets.

      • Dave says:

        Hi Ianw16

        I can understand your first paragraph and why, but your further comment just looks too simple . who knows what’s inside it for sure,

        With Philae out of action our look through the comet seems to be compromised, It did not even find the large pits that we have seen close ups of recently..

        Your description looks like something I could of read in the 70’s and is a bit oat odds with what we have found while traveling along side it for the last couple of years..

        But yes as has been said many times on the blog, it is difficult to over come our bias of geological processes that we see on earth.

        • ianw16 says:

          @Dave,
          I’m really not sure what you are saying here. Philae’s CONSERT instrument did not fail. There are papers on its findings. Initially, due to the uncertainty over its location, the results could not be constrained as accurately as they would have liked. That is no longer a problem. It hasn’t been a problem for some time, given that they constrained the area quite tightly prior to it being resolved in the recent image.
          So, just for the sake of clarity, I’ll repeat; 67P is not a rock. There is plenty of evidence of that. There was plenty prior to this mission.
          It was not blasted off of another rock, either by an impact, or some sort of invisible interplanetary lightning bolt., or any other kind of neo-Velikovskian woo.

          And I don’t see how what I’ve written in the paragraphs following the first one is something that you could have read in the 70s, or is at odds with results.. It is purely evidence based. Perhaps you could be specific?
          I’ll be happy to link to all that evidence if you haven’t read it as yet.
          Two of the CONSERT papers are here:

          ‘Properties of the 67P/Churyumov-Gerasimenko interior
          revealed by CONSERT radar.’
          Kofman, W., et al.
          http://science.sciencemag.org/content/349/6247/aab0639

          ‘A porosity gradient in 67P/C-G nucleus suggested from CONSERT and SESAME-PP results: an interpretation based on new laboratory permittivity measurements of porous icy analogues.’
          Brouet, Y. , et al.
          http://mnras.oxfordjournals.org/content/early/2016/09/05/mnras.stw2151.abstract

          Of course, we could go on about the density of comets, but that has been known for decades. We could also mention the subsurface ice which has been detected at this comet by MIRO. Again.
          Or the solid ice excavated by the DI impact. Again. However, that has also been known for over a decade (to most of us).
          Or the ice detected in large cometary outbursts, such as at 17P/Holmes.
          However, none of this is particularly surprising, given that we know that comets are composed primarily of dust and ice. As per all the evidence.
          Unless I’ve missed something? In which case I’ll be happy to look at it.

      • Pete_Yates says:

        Interesting, thanks. But I think a rocky object in Space smaller than an asteroid is actually a ‘meteoroid’. If it enters Earth’s atmosphere it is a ‘meteor’. If some of it survives and reaches the ground it is a ‘meteorite’.

        • ianw16 says:

          @Pete,
          True, but terminology aside, the point I was making is that comets most definitely are not rocks, and nor were they once part of a larger body (except in the cases where comets themselves split, or are otherwise disrupted).

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