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Out-of-Control Satellite Threatens Spacecraft

Discussion in 'General Satellite Discussion' started by LarryFlowers, May 3, 2010.

  1. James Long

    James Long Ready for Uplink! Staff Member Super Moderator DBSTalk Club

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    That is where lost satellites tend to go when they lose their station keeping abilities. When ground control lost the ability to make the minor adjustments needed to keep it in it's box it started moving toward the nearest natural resting spot. It will take months to get there and everything in its way will have to move to let it pass. But it should all turn out fine.
     
  2. GoPokes43

    GoPokes43 Mentor

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    I understand that there are natural resting places on the geosynchronous orbit, but I am wondering why those locations exist and why they are where they are? Obviously it's not the moon or sun, since neither remain stationary in relation to those naturual resting places. Is it a function of the shape or density of earth?
     
  3. scooper

    scooper Hall Of Fame

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    It's the physics of 2 relatively large bodies and one relatively small body and how the gravitational forces play out.
     
  4. GoPokes43

    GoPokes43 Mentor

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    That is what lagrangian points are. There are five lagrangian points related to two relatively large bodies. With respect to the moon and earth, three are in the moon's orbit, one is slightly beyond the moon and one is slightly inside the moon (all five travelling with the moon's orbit). Side note: none of them can hold a satellite in place indefinately because the sun disturbs them somewhat and a satellite would need to engage in station-keeping maneuvers.

    So, none of these points are on the geosynchrous orbit and none of them are stationary. Therefore, there seems to be no relation between the earth-moon Lagrangian points and the points at which satellites would naturally aggregate at 105 degrees west and 75 degrees east along the geosynchronous orbit.

    So, back to the question. Why do they congregate at these two points? (I realize that some reports refer to these points as libration points and that's fine since libration simply means to balance or sway, but they certainly are not Lagrangian points.)

    So, as I was typing this, I did find another internet discussion that indicates these libration points on the geosynchronous orbit are perhaps related to gravity wells on earth and the slightly elliptical nature of mass distribution within the earth. So, I guess I've answered my own question... :)
     
  5. Stewart Vernon

    Stewart Vernon Roving Reporter Staff Member Super Moderator DBSTalk Club

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    Since nobody else is going to say it... I will.

    To quote ZZ Top...

    "There's a lot of nice girls out there"...

    RE: LaGrange

    :)
     
  6. Lee L

    Lee L Hall Of Fame

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    I kind of wondered about this also as when you look up Libration point on Wikipedia, it forwards to Lagrange ponit, which are not the same thing, at least in this case.
     
  7. Nick

    Nick Retired, part-time PITA DBSTalk Club

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    The...
    From SkyReport:
    MediaBiz.com
     
  8. James Long

    James Long Ready for Uplink! Staff Member Super Moderator DBSTalk Club

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    The entire passage to 105 will take that long ... but passing each satellite will take less time. It will be like a very long solar conjunction for each satellite that is passed by Galaxy 15 (until G15 shuts down). The broadcast interference will only affect satellites using the same band as G15. All the DBS providers need to worry about is physical interference. Adjusting their orbits to let the drunk satellite pass by.
     
  9. Lee L

    Lee L Hall Of Fame

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    So, eventually the satellite lost earth lock, the solar panels were not able to charge the battery, it ran out of juice and then reset. I guess it then drifted enough so that it charged the battery and it started responding to commands and began station keeping.

    Now they think they can upload new software and actually use it. :eek:


    http://www.spaceref.com/news/viewsr.html?pid=35643
     

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