back to article Bouncy bouncy: Comet probot Philae landed twice

ESA scientists are still a bit baffled about just how they managed to land their Philae probe on the surface of Comet 67P after the craft's harpoons failed to fire into the rock. And they think it’s possible Philae landed not once, but twice. It's the first time ever humanity has set down on a comet – and this one's 500 …

  1. Will Godfrey Silver badge
    Happy

    Well now,

    It obviously is a child. It enjoyed landing so much that it decided to jump up, spin around and do it again, leaving footprints all over the place in the clean sand.

    1. Mark 85 Silver badge

      Re: Well now,

      And it didn't land on it's head during one of the bounces.

  2. DuncanL

    My lander is full of eels.

    Would you like to come back to my comet, bouncy, bouncy?

    1. Ugotta B. Kiddingme Silver badge
      Coffee/keyboard

      Re: My lander is full of eels.

      I regret that I can only upvote you once. That was worth having to clean my monitor.

  3. Hans 1 Silver badge
    Alien

    I do think that the press coverage of all this is a tad light. Imagine the complexity of getting a craft out of our atmosphere, speed it up using amongst other means gravitation from earth and mars, have it speed into space at high speed for ten years on a journey of 6 billion km, then reach orbit of a comet moving at 18km/s some 500 000km away.

    That alone is quite a "brave" idea ... some boffin then says, we might as well land a robot on it, and they listen to this guy!!!!! Knowing that you have 28 minutes delay.

    These guyz actually made it happen! They had to trust their theory!!!!

    1. TheProf Silver badge

      "I do think that the press coverage of all this is a tad light. "

      I agree but 'news' today is more about human interest stories. Sky News did 15 minutes at 7 o'clock which surprised me. Firstly because it was Sky and secondly that I actively sought it out because the BBC were doing a very serious piece from Lebanon. Or Syria. Or Jordan. I forget which.

      1. FlatSpot
        Facepalm

        Newsnight seemed more obsessed with a scientists tattoo much too his disgust

    2. Destroy All Monsters Silver badge
      Paris Hilton

      They had to trust their theory!!!!

      Magic engineering, how does it work?

    3. Anonymous Coward
      Thumb Up

      Meanwhile on Earth

      some boffin then says, we might as well land a robot on it, and they listen to this guy!!!!! Knowing that you have 28 minutes delay.

      It certainly gives some perspective about people that can't park a family car back here on Earth without several attempts.

      Multiple beers to all all involved in the project.

    4. lambda_beta
      Linux

      I do think that the press coverage of all this is a tad light.

      Of course it's "a tad light", it news about science!. Most people could care less about anything factual or actually interesting. "News" is all about what sells, and science does not sell.

      1. BonerNose
        Headmaster

        Re: I do think that the press coverage of all this is a tad light.

        Downvoted for "could care less".

      2. A J Stiles
        FAIL

        Re: I do think that the press coverage of all this is a tad light.

        Most people could care less about anything factual or actually interesting.
        The ability to care less about something implies that one must already care about it to some fairly strong degree. Surely what you really mean is, "most people could care more about anything factual or actually interesting".

  4. KrisMac

    What is the pull of gravity of that rock?

    Given that the comet itself isn't big enough to pull itself into a ball I would assume the gravity is very low? So the (second) landing would have been potentially quite slow and soft?

    1. Destroy All Monsters Silver badge
      Paris Hilton

      Re: What is the pull of gravity of that rock?

      Assume a spherical cowhot fudge sundae with the following physical characteristics:

      Mass ~1.0 ×10^13 kg

      Mean density ~0.4 g/cm³

      This yields a sphere of ~1800m radius if I am not mistaken, so all the mass underneath will attract you with 2 * 10^(-4) N/kg at the ball's surface.

      This is not much.

      1. Rusty 1

        Re: What is the pull of gravity of that rock?

        "hot fudge sundae" - that sir, is where you are wrong.

        This is an interstellar baked Alaska. Totally different coefficients of mass, density, magic, coolness, and boffinnry.

        1. KrisMac

          Re: What is the pull of gravity of that rock?

          you forgot Yummyness (or does that epithet only apply to attractive soccer mums in SUV's?) :-)

      2. Anonymous Coward
        Anonymous Coward

        Re: What is the pull of gravity of that rock?

        I'm not sure about this but your mean density seems a bit low as it gives 400kg/m3.

        Loose gravel is about 1500kg/m3 and crushed stone is about 1600kg/m3, even crushed ice is about 600kg/m3. Solid limestone and marble are both around 2500kg/m3

        1. Eddy Ito

          Re: What is the pull of gravity of that rock?

          Those things are that dense because they've been pulled together for quite some time rather nicely by gravity here on Earth. Most of your sedimentary stone can be much less dense without the big squeeze it undergoes here and that is likely the case way out yonder even though it's likely just iron and ice, although confirmation of it's true makeup would be nice.

          In all, great stuff. It may seem easy to hit a dinner plate with a pea but not when you're in London and the plate is in Calais.

      3. randomengineer

        Re: What is the pull of gravity of that rock?

        nice ref to Lucifer's Hammer.

        well done

      4. DiViDeD Silver badge

        Re: Hot Fudge Sundae

        ... which, of course, falls on a Tuesdae this year.

        +1 for the Niven reference, sirrah!

  5. Anonymous Coward
    Anonymous Coward

    "It’s complicated to land on a comet"

    I don't know about Dr. Ulemac, but I would feel very smug being able to utter those words when someone asks me how my day's been. :-)

    1. EddieD

      Re: "It’s complicated to land on a comet"

      I dunno, it's not rocket sci...oh, wait...

  6. Gannon (J.) Dick

    Well done Philae!

    About the bounce ... experienced travelers know you always get in the line for the loo before you get in the line for Customs. No problem :)

  7. Stratman

    With such low gravity...

    .. how is the mother ship being held in orbit?

    1. d3vy Silver badge

      Re: With such low gravity...

      string

    2. BonerNose

      Re: With such low gravity...

      It isn't being 'held' as such - not by gravity anyway.

      It's in a sort of triangular orbit, so presumably once it's fuel runs out, it will just drift away.

      http://www.esa.int/spaceinvideos/Videos/2014/01/Rosetta_s_orbit_around_the_comet

  8. Marketing Hack Silver badge
    Go

    I hope that they can drill without being solidly anchored!

    I'd imagine that the gravity is so weak that actually pressing the drill into anything solid would start to push the probe back into space!

  9. Mystic Megabyte
    Linux

    Astro Chicken

    Were the boffins using this simulator or did they fool children into thinking that it was just a game?

    https://www.youtube.com/watch?v=Zgt17LwmT7c

  10. paulc

    Not looking good... :(

    Appears to be on it's side...

    http://www.esa.int/var/esa/storage/images/esa_multimedia/images/2014/11/welcome_to_a_comet/15048351-1-eng-GB/Welcome_to_a_comet.jpg

    1. Daz555

      Re: Not looking good... :(

      I don't think that left hand portion od dark is "space" I suspect it is shadow and when we see a full panorama we'll know for sure.

  11. This post has been deleted by its author

  12. Bunbury

    We need Georgie Fame

    "Rosetta, are you better? Are you well, well, well?"

    OK, it's not Philae but it's the best I could do.

  13. NP-HARD
    WTF?

    "Despite the unorthodox landing..."

    I guess the orthodox one is smashing into the comet at huge speed.

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