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Rosetta's comet mission discussion thread

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  1. Feb 2, 2012 #1

    marcus

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    This YouTube describes the Rosetta mission


    Here is the print version:
    http://science.nasa.gov/science-news/science-at-nasa/2012/02feb_rosetta/

    Rosetta is a European (ESA) mission with some Usa instruments on board. It carries a lander that will descend onto the comet surface, take pictures at the surface, and study the comet.

    Rosetta will continue to orbit the comet for about 16 months, while the comet goes in close to the sun, evaporates some making a tail, and then swings out away from the sun again.

    The lander's feet will have to drill into the comet material in order to be anchored firmly, because the gravity is very slight.
     
    Last edited by a moderator: Sep 25, 2014
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  3. Aug 26, 2014 #2

    marcus

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    http://science.nasa.gov/science-news/science-at-nasa/2014/26aug_rosetta/

    Landing is expected in mid-November.

    The article says that 3 of the five sites are on the small lobe, and 2 on the large lobe (which surprised me).

    So they have narrowed the choice down to a "short list".

    I'd be interested to know if you understand what criteria were used in the selection, other than a level patch clear of obstacles.
     
    Last edited: Aug 26, 2014
  4. Aug 26, 2014 #3

    marcus

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  5. Sep 8, 2014 #4

    Dotini

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  6. Oct 3, 2014 #5

    Dotini

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  7. Nov 10, 2014 #6

    Dotini

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    They may well attempt the landing tomorrow, November 11.
    http://rosetta.jpl.nasa.gov/

    The landing looks almost impossibly difficult. IMO, they will need plenty of luck. But I wish them well.
     
  8. Nov 10, 2014 #7

    marcus

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    I too! The landing time I see projected is for Wednesday 12 November.

    "Rosetta will deploy Philae on November 12 at 12:35 AM PST. Confirmation of the landing will arrive at ground stations around 8:03 AM PST."

    "Rosetta will deploy Philae on November 12 at 3:35 AM EST. Confirmation of the landing will arrive at ground stations around 11:03 AM EST.

    "Rosetta will deploy Philae on 12 November at 08:35 UTC from a distance of 22.5 km. Confirmation of the landing will arrive at ground stations around 16:00 UTC"



    the chosen landing site used to be called "Site J" and is now renamed Agilkia, after an island in the Nile.
    http://sci.esa.int/rosetta/54870-farewell-j-hello-agilkia/

    Here is a beautiful photograph of terrain on the comet:
    http://blogs.esa.int/rosetta/2014/10/31/cometwatch-28-october/
     
    Last edited: Nov 10, 2014
  9. Nov 11, 2014 #8
  10. Nov 11, 2014 #9
    Hello Everyone - 2 links for your enjoyment....

    The EESA live stream.... http://new.livestream.com/esa/cometlanding

    and a neat audio recording of Rosetta - https://soundcloud.com/esaops/a-singing-comet [Broken]

    Enjoy!
     
    Last edited by a moderator: May 7, 2017
  11. Nov 11, 2014 #10
    Wow this is really exciting. This will be the first time (that I know of) humans will ever get a close-up view of the surface of an object of such low gravity.
     
  12. Nov 11, 2014 #11

    berkeman

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    Wow, pretty amazing! :-)
     
  13. Nov 11, 2014 #12

    mfb

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    Itokawa is smaller, and we have samples on earth. I didn't see pictures directly taken from the surface, however.

    It will be the first landing on comet.

    That doesn't sound good, but apparently they are confident Philae will make it. Well, the escape velocity is tiny.
     
    Last edited: Nov 11, 2014
  14. Nov 11, 2014 #13

    marcus

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    Glad you liked it, Berkeman! That terrain was photographed just recently, on 28 October. In case anyone new to the thread hasn't seen it, here's the link:
    http://blogs.esa.int/rosetta/2014/10/31/cometwatch-28-october/

    About the landing site, formerly called "Site J" and now renamed after an island in the Nile river (Agilkia) that plays some role in the the Rosetta stone story, that landing site is on the very top of the duck's head if you imagine the comet as a toy plastic duck the large roundish lobe being the body and the smaller lobe being the head.
    And interestingly, the way the comet is rotating it tumbles head over heels so the top of the head comes swinging by you, in the animation, and it looks like a question of precise timing to land on it.
     
  15. Nov 11, 2014 #14

    marcus

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    Here is an animation that shows the rapidly tumbling comet and the orbit being traced out by the Rosetta spacecraft.
    http://www.esa.int/spaceinvideos/Videos/2014/10/Rosetta_close_orbits_to_lander_deployment
    Around 45 seconds into the clip they shift to slo-mo. And they show the lander's path as it is released and descends to the surface (at Site J aka Agilkia, the very top of the duck's head).
    The landing occurs at around 54 seconds into the video.

    After that, Rosetta makes some complicated orbit changes in order to be positioned well for communication with the lander and for serving as a relay.

    Incidentally the lander will need to plant two small harpoons into the comet surface material in order to be anchored securely, given the comet's weak gravity.
     
    Last edited: Nov 11, 2014
  16. Nov 11, 2014 #15

    marcus

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    Churyumov-Gerasimenko rotates once every 12.7 hours, or about twice in an Earth day.
    The landing site (on top of the duck's head) is about as far out from the center of gravity as any part of the comet surface, so it would be rotating as fast or faster than any other part of the surface. (the axis of rotation corresponds to a minimal width). My guess is that its radial distance from the center of rotation is at least 2 km. So if my estimates are right the landing site if moving at least 4π kilometers in 12.7 hours. That is at least 1 kilometer/hour.

    Well that's not too bad.
     
  17. Nov 12, 2014 #16
    ESA seem to be broadcasting live here:
    (Quote: "Waiting for confirmation of landing. Expected at around 16:00 UTC")
    http://rosetta.esa.int/
     
  18. Nov 12, 2014 #17

    OmCheeto

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    And Philae made NASA's Picture of the Day.

    She has her own twitter account, as does Rosetta.
    Philae's last name is Lander. I did not know that.

    X4-Y4nc5_normal.jpe Philae Lander @Philae2014 · 15m
    .@ESA_Rosetta I will send you hundreds of postcards from #67P :) #CometLanding

    a6286c08618d966740207142a62eda84_normal.png ESA Rosetta Mission @ESA_Rosetta · 25m
    .@Philae2014 :) My back is chilly now you’ve left, but I'm in a better position to watch you now. Send me a postcard! #CometLanding

    X4-Y4nc5_normal.jpe Philae Lander @Philae2014 · 20m
    .@ESA_Rosetta WOW! I feel like I’m floating! And #67P is closer and closer… #CometLanding

    X4-Y4nc5_normal.jpe Philae Lander @Philae2014 · 24m
    Finally! I’m stretching my legs after more than 10 years. Landing gear deployed! #CometLanding

     
  19. Nov 12, 2014 #18

    Dotini

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    I have heard from BBC radio that the important "down" thruster has failed.

    A big question is the nature of the surface. It may turn out that pitons and jam nuts are more useful than harpoons and ice screws.
     
  20. Nov 12, 2014 #19
    In just a few minutes NasaTV and other sites will be posting Live Coverage. Someone already knows if it made it safely as it would have radio'd back almost an hour ago. Prior to that, during descent it the lander radio'd back to Rosetta and seemed to confirm that pictures will be sent. The last I read, it is still given 75% chance of success. I can hardly sit still.
     
  21. Nov 12, 2014 #20
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