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D10 Satellite TECH THREAD - HD Testing Schedule / Press Releases / Location

Discussion in 'DIRECTV General Discussion' started by Sixto, Jul 6, 2007.

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  1. Sep 7, 2007 #1901 of 2718
    lwilli201

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    Missouri
    :scratch:
     
  2. Sep 7, 2007 #1902 of 2718
    oakwcj

    oakwcj Lower Echelon

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    Sorry, but that's NOT the latest. It's from day 249 of this year. The most recent is from day 250.
     
  3. Sep 7, 2007 #1903 of 2718
    dcben

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    Donshan,

    I understood every word!:scratch:

    And it does clear up why approx. 1.002710 rev/day keeps a satellite over the same spot. And it confirms our conclusion that in the next day or so one indication that we are on our way would be a TLE with a 1.002500 element.

    Anyone disagree????:ramblinon

    Ben
     
  4. Sep 7, 2007 #1904 of 2718
    donshan

    donshan Godfather

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    I would say your's is better, because it is a shorter summary. Besides two versions of this subject are always useful. :)
     
  5. Sep 7, 2007 #1905 of 2718
    oakwcj

    oakwcj Lower Echelon

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    The latest elset has a period of 23h,56m,and FIVE seconds, so I guess that's a little progress.
     
  6. Sep 7, 2007 #1906 of 2718
    dcben

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    23hr. 56 min 4 sec = 86164 sec.

    24 hr = 86400 sec

    86400/86164 = 1.002739

    Again, suggests we need a TLE element of 1.0025000 or thereabouts to make a three day trip to -102.775 W

    This has been fun. Even if I'm totally wrong.:beatdeadhorse:

    Waiting for a new TLE.

    Ben
     
  7. Sep 7, 2007 #1907 of 2718
    LameLefty

    LameLefty I used to be a rocket scientist

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    Great explanation from the astronomy folks, thanks! :D

    I'm a hack amateur (10" Dob that I like to hunt Messiers with on cold, dry nights) but I forget all the details about the day/date stuff.

    On the other hand, it illustrates why spacecraft engineers (as opposed to true orbital mechanics guys - and I do know a few who work at JSC and MSFC) are really more concerned with inclination and eccentricity (and a couple of those other pesky elements) for getting a handle on small movements of the satellites. :lol:
     
  8. Sep 7, 2007 #1908 of 2718
    n3ntj

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    Lancaster,...
    Thanks LameLefty..that was a very interesting writeup about the seasons. So, essentually, the Earth is always tilted..depending upon where it is located in its orbit around the sun, however, the northern half is facing the sun more than the southern half at one point (which we in this hemisphere call summer) and at the opposite half of this Earth orbit, the southern half is more directly facing the sun.

    In essence, since the Earth is always tilted, the satellites in GSO are also positioned with this same tilt.

    I know we are way off topic, but this is pretty interesting. Thanks.
     
  9. Sep 7, 2007 #1909 of 2718
    21hawk

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    The earth does have a wobble also, but it's just a couple of degrees over several thousand years, IIRC.
     
  10. Sep 7, 2007 #1910 of 2718
    cygnusloop

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    The tilt of the Earth's axis has a precession, like a spinning top. It will precess through 360 degrees in 26,000 years (~1 degree every 72 years). This means the seasons will have shifted by 6 months in 13,000 years. With the lifespan of communications satellites being 15 or 20 years, at most, it is a non-issue.

    P.S. Because of this precession, the zodiacal sign that you think you were born under is wrong. Since these signs were defined a bit over 2000 years ago, they have shifted to the west by about one sign. So, for example, if you thought you were a Gemini, you are really a Taurus, If you thought you were a Virgo, you are indeed a Leo. Also, in 13,000 years, Polaris won't be the North star anymore. But don't worry, it will be again in 26,000 years. :)

    Back to our regularly scheduled thread...
     
  11. Sep 7, 2007 #1911 of 2718
    21hawk

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    Yeah, what he said.
     
  12. Sep 7, 2007 #1912 of 2718
    bbaleno

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    Sorry I can resist !rolling !rolling !rolling !rolling !rolling !rolling !rolling !rolling !rolling !rolling !rolling !rolling !rolling !rolling !rolling !rolling
     
  13. Sep 8, 2007 #1913 of 2718
    richlife

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    Just stepped in to catch up on this thread -- not sure that was a good move....
    :D :D :D

    Let's see now -- does this mean that the Earth's eccentricity is probably small? Or was that just my stagger? C'mon D*, give these guys something to sink their teeth into.
     
  14. Sep 8, 2007 #1914 of 2718
    bakers12

    bakers12 ΔS > 0

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    Chicago -...
    Still looks parked to me.
    Code:
    DIRECTV 10 
    1 31862U 07032A   07250.43441108 -.00000125  00000-0  10000-3 0   759
    2 31862 000.0811 296.0095 0000210 337.8947 126.0388 01.00271797   649 
     
  15. Sep 8, 2007 #1915 of 2718
    dcben

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    We've had that TLE since post 1862. Not news.:nono2:

    Ben
     
  16. Sep 8, 2007 #1916 of 2718
    mlcdorgan

    mlcdorgan Godfather

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    Post from yesterday not todays #'s


    I am sorry, I was just trying to participate, and I went to space track and logged in and did a search for latest most recent TLE and that is what it gave me.

    How do you get the latest one? just trying to learn a little here, very interesting stuff, and on the edge of your seat feeling!
     
  17. Sep 8, 2007 #1917 of 2718
    syphix

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    Most recent (still from yesterday, 9/7/07):
    DIRECTV 10
    1 31862U 07032A 07250.43441108 -.00000125 00000-0 10000-3 0 759
    2 31862 000.0811 296.0095 0000210 337.8947 126.0388 01.00271797 649

    Still at 102.5585.
     
  18. Sep 8, 2007 #1918 of 2718
    John4924

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  19. Sep 8, 2007 #1919 of 2718
    LameLefty

    LameLefty I used to be a rocket scientist

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    If you go to Space-Track.org and do a search by satellite common name or international number and plug in the info for Directv 10, you should get the latest - once in awhile they post the numbers out of order, which is why you ended up with an older elset - I suspect that's what happens when a set of measurements isn't exactly perfect and someone has to massage the data to correct the glitch or re-run the data through some other program to "fix" it. Often by then another elset has been generated in the interim, so that that other set is by then obsolete.
     
  20. Sep 8, 2007 #1920 of 2718
    oakwcj

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    Because they sometimes list them out of order, it's helpful to request the last five elsets for some context. Then you can check the epoch date element to be sure. If you set up a favorites page with the D10, you'll also get a listing which may be out of order. But you can also check for the latest elset from that page. Thanks to Space-Track's little idiosyncracies, it's easy to be misled.
     
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