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Directv 1 to be moved to disposal orbit

Discussion in 'DIRECTV General Discussion' started by lwilli201, Feb 8, 2009.

  1. Feb 8, 2009 #1 of 62
    lwilli201

    lwilli201 Hall Of Fame

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  2. Feb 8, 2009 #2 of 62
    longrider

    longrider Well-Known Member DBSTalk Club

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    I'd say they got their design life out of that bird. 15 years + is respectable
     
  3. Feb 8, 2009 #3 of 62
    Scott in FL

    Scott in FL Godfather

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    For those who might be interested...

    Usually what happens is the satellite's electronics are still in perfect working order, but the fuel runs out (batteries are a separate concern). No fuel means they can no longer "station keep" the satellite. In other words, keep the satellite in its proper location. Plus, they have to save a bit of fuel to boost the satellite out into space at End Of Life.

    The company I used to work for, COMSAT, developed a maneuver where the satellite's East-West thrusters were turned off to save fuel. This was OK for awhile, but in time the satellite would move North and South, resulting in a figure-8 pattern (also known as inclined orbit). The trick was to use tracking antennas on the ground. No problem for big teleports, but not at all practical for Direct-to-Home satellite service!

    So this Direct TV bird is probably still in working order... just our of gas. RIP.
     
  4. Feb 8, 2009 #4 of 62
    dodge boy

    dodge boy R.I.P. Chris Henry

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    Why not just have it burn up during re-entry?
     
  5. Feb 8, 2009 #5 of 62
    lwilli201

    lwilli201 Hall Of Fame

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    I am sure it would take a great deal of fuel to orchestrate a controlled reentry to a safe place on earth, and remember, these satellites are about 35,000 Kilometers up there. There are a lot of low orbit bodies that may be in jeopardy of being hit and the liability that goes with a possible landing in the middle of your street if they do not completely burn up.
     
  6. Feb 8, 2009 #6 of 62
    dodge boy

    dodge boy R.I.P. Chris Henry

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    I was just curious 'cuz I thought the shuttle went futher out than them, and also the Space Station.... Guess they are furthest out... Where do they go? Crash into the moon? Get sucked into the sun or another planet? Just curious..
     
  7. Feb 8, 2009 #7 of 62
    rccoleman

    rccoleman AllStar

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    With objects in space, it's pretty hard to fully understand the scale of things. The space shuttle goes up to about 186 miles, while the DirecTV satellites are typically around 22,000 miles high. In comparison, the moon is 238,857 miles out.

    Rob
     
  8. Feb 8, 2009 #8 of 62
    MattWarner

    MattWarner Legend

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    Nope. Geostationary satellites are out at 22,300 miles.. shuttle and station are MUCH much closer to the earth.

    Think about this: the satellite at 22,300 miles out takes 24 hours to go all the way around the earth, thus it appears to stay in the same place if you look from the earth. The shuttle and station circle the earth every 90 minutes or so. Therefore, either they are moving much much faster or they are much much closer to the earth.

    I love space things...
     
  9. Feb 8, 2009 #9 of 62
    Newshawk

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    The International Space Station is in a Low Earth Orbit (LEO)-about 190 miles above Earth. The space shuttle has an operational altitude of 100 to 520 nautical miles. Communications satellites are in geostationary orbit on the Clarke belt, at 22,236 mi above the Equator.

    But isn't DirecTV 1 the satellite at 72.5?
     
  10. paragon

    paragon Godfather

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    Maybe the 72.5->MPEG4 transition will happen faster than D* wanted.
     
  11. Mertzen

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    Nah. just an orbit either lower or higher where they pose no risk to live birds.
     
  12. Win Joy Jr

    Win Joy Jr AllStar

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    Geo Birds are typically boosted into a HIGHER orbit, then the fuel system is safed (vented / depressurized), and finally the electronics are disabled.

    And each orbiting asset has an end-of-life disposal plan.
     
  13. Montezuma58

    Montezuma58 AllStar

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    So does this mean Pegasus is really really done.:lol:
     
  14. Tom Robertson

    Tom Robertson Lifetime Achiever DBSTalk Club

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  15. Newshawk

    Newshawk Hall Of Fame

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    Thanks, Tom! I forgot about D-1R.
     
  16. B-Town Blues

    B-Town Blues Cool Member

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    But isn't this just delaying the problem. Even if they boost the dead sat to a 30,000 mile orbit, it's still going to come down at some point. It might be 100-200 years from now, but it will come down, and this time there will be no way to have any control over its descent path (its completely out of fuel now). Maybe we're counting on a future capability where a space faring garbage truck goes up and collects all of the dead satellites and hauls them to the Smithsonian Museum for display, but I wouldn't like to count on that. I think this philosophy of a dead sat orbit is just a short term solution to a long term problem. What goes up will eventually come down.
    I'm not a rocket scientist, just my 2 cents worth...
     
  17. Tom Robertson

    Tom Robertson Lifetime Achiever DBSTalk Club

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    Hopefully someone closer to the industry can explain the parking orbit that the international agencies have agreed to.

    Cheers,
    Tom
     
  18. xIsamuTM

    xIsamuTM Icon

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    you know, I always figured they'd burn up in orbit too. there's not a safe way you can aim it to hit the ocean? how much mass is in the average sat anyway? will it even hit the ground or just vaporize in space?
     
  19. RunnerFL

    RunnerFL Well-Known Member

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    Can't they just get the shuttle to deliver some fuel? ;) :lol:

    On a serious note: Good information, thanks!
     
  20. LameLefty

    LameLefty I used to be a rocket scientist

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    Satellites left alone in GSO or higher are essentially permanent. It will be THOUSANDS of years before they deorbit, maybe even longer. In fact, modeling these processes is chaotic (meaning teeny-tiny variances in your assumptions or precision of calculations makes a huge difference in your results), so it's quite possible that the interactions of the moon, the sun, and even near-earth asteroids might well toss them out of orbit eventually too.

    In any event, you want a disposal orbit higher for a number of reasons. The biggest one is that it takes a lot of delta-V to deorbit the satellite and that means a lot of fuel must be kept in reserve. It actually takes a lot less fuel to move it up a few hundred miles and out of the way. International agreements also require that deorbiting satellites must be targeted to avoid land and (ideally) shipping lanes too. That takes some precision and most satellite operators don't have that kind of experience with targeted entries (NASA, Russia and ESA do, and the Chinese could probably figure it out quickly if they don't already). The second main reason is that higher = out of the way of launches to operational slots and drifting between slots.
     

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