Re: TJM obs of 2008 Nov 28 UTC; updated Lacrosse 2 elements

From: mike1@mgte.com
Date: Sat Nov 29 2008 - 17:35:02 UTC

  • Next message: Robert Holdsworth: "Very birght ISS with SST-126 behind.)"

    Ted,
    
    VERY interesting. I plugged your elements from Lacrosse 2 into 
    InstrackTrack 1.50 and the results of the following orbit were 
    calculated from my positoin, 30.59, -86.96 here in FL:
    
    11-30-08 @ 16:00 UTC, Bearing 229.9, Az -7.6
    
    What I want to know, will my observations be correct? Also, how often 
    do the elements have to be updated due to drag? Thanks for any info 
    you can give.
    
    Mike C.
    (on the worlds largest sandbar)
    
    
    On 28 Nov 2008 at 20:07, Ted Molczan wrote:
    
    > Just prior to my observation of 05016A, I observed without optical
    > aid, ISS and STS 126, separated by about 4 deg, on a low pass in the
    > NNW.
    > 
    > Lacrosse 2 was 15 s late relative the latest elements (below),
    > confirming Russell Eberst's observation yesterday that it was running
    > late.
    > 
    > Lacrosse 2      18.0  4.5  0.0  3.6 v
    > 1 21147U 91017A   08329.77017445  .00000050  00000-0  72139-5 0    05
    > 2 21147  67.9900 210.8587 0004500 277.5806  82.4194 14.76152093    09
    > 
    > Using our two points, I have updated the above elements, correcting
    > only RAAN, mean anomaly and motion; residuals are low:
    > 
    > 1 21147U 91017A   08333.97130653  .00000050  00000-0  72139-5 0    09
    > 2 21147  67.9900 199.6257 0004498 273.1067  86.9551 14.76087237    07
    > 
    > Its mean altitude is now about 200 m higher. It raised its orbit about
    > 100 m in mid October. One theory is that these manoeuvres are thruster
    > firings to desaturate reaction wheels; collision avoidance may be
    > another possibility worth studying.
    > 
    > 28646 05 016A   2701 G 20081128234103590 17 25 1453974+593023 18 S
    > 28646 05 016A   2701 G 20081128234121000 17 25 1424897+625617 37 S
    > 28646 05 016A   2701 G 20081128234224650 17 25 1136047+691996 96 S
    > 21147 91 017A   2701 G 20081128235048340 17 25 1149891+672338 18 S
    > 
    > IOD format: http://www.satobs.org/position/IODformat.html
    > 
    > Site 2701: 43.68764 N, 79.39243 W, 230 m = 0.015 deg
    > 
    > Ted Molczan
    > 
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