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Rosetta Mission

So they sent a probe to meet a comet and drop a three-legged robot on its surface which bounced twice to end up lying on its side. Apparently the harpoons that should have fired to anchor the robot to the comet did not go off. This is why we can't have nice things. Murphy's law sucks! The drill which was supposed to get samples is not pointing down!!

I hope they can still do something before they run out of power.


  • Does the comet generate gravity of any kind? Or is Rosetta more or less flying "with" the comet?
  • StingrayStingray Elite Ranger
    edited November 2014
    The comet is over 4km in length, so I'm guessing it should generate some gravity, even though it is probably not much. The robot did a 1km bounce that took two hours during the landing... which is a hair raising thought all by itself. lol
  • croxiscroxis I am the walrus
    Anything with mass generates gravity. Enough so that the lander weighs a few ounces.
  • I guess what I meant is that does it generate enough gravity for the gravity to be relevant.
  • StingrayStingray Elite Ranger
    edited November 2014
    I don't know enough about the physics involved to give an approximative, much less a definitive answer (not that anybody was asking me, lol). Those involved in the Rosetta mission had to make educated guesses since they didn't know the exact composition of the comet beforehand to figure out the accurate gravitational parameters that caused the bouncy landing. On face value there appears to be enough gravity and matter to keep the robot stuck in place. They ran out of power last night but they were able to download some valuable data nonetheless before the communcation gear went silent.

    Edit: Our Moon that orbits Earth has a diameter of 3474km and the astronauts walking on its surface experienced 1/6th of Earth's gravity. The comet is 868.5 times smaller than our Moon. Let's just say, there isn't much gravity, but enough to have a robot bounce off and drop down again!!
  • BigglesBiggles <font color=#AAFFAA>The Man Without a Face</font>
    One (not that great) analogy I heard was that lifting the lander would be like lifting a piece of paper on Earth.

    Another problem that apparently occurred with the landing was that their best guess for the surface was for a relatively soft, powdery surface. Instead, it turned out to be rock hard.
  • ShadowDancerShadowDancer When I say, "Why aye, gadgie," in my heart I say, "Och aye, laddie." London, UK
    Given the number of unknowns that the lander faced, the fact that it got down at all is amazing!
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