Re: Hook Line and Sinker

From: B Gimle @ComHem (@ComHem)
Date: Tue Mar 17 2009 - 10:57:46 UTC

  • Next message: Peter Wakelin: "SATOBS 2009 March 16"

    As John noted, elset age is not the only factor, but neither are LEO/MEO/GEO 
    nor the semi-major axis.
    That's why I wrote my TLEage.exe Windows program (misleading name - it 
    estimates prediction error based on age, drag and MM)
    What I don't account for are gravitational perturbations on HEO/GEO, and 
    maneuvering GEO/spysats.
    Compare the estimates (376,303,287,131... seconds, sorted with QSORT  )
    and drag factors (0.00000500,0.00003000...) in the following sections of 
    output.
    A high drag satellite like USA 161 is much more uncertain after three months 
    than a "stable" satellite like KH 9-18 after 21 months.
    
    IGS 4B          376 07005B
    1 30587U 07005B   08185.00631613 0.00000500  00000-0  18956-4 0    08
    2 30587  97.3000 299.6051 0006000 352.9424   7.0574 15.26902000    09
    USA 161         303 01044A
    1 26934U 01044A   08349.73834853 0.00003000  00000-0  61331-4 0    02
    2 26934  97.9043  97.6506 0467060 230.3701 129.6298 14.76942683    07
    USA 89 r        287 92086C
    1 22519U 92086C   08280.00993814 0.00000550  00000-0  60988-4 0    04
    2 22519  56.9061  31.4768 3236274 241.3520  82.4226  8.79181323    07
    KH 9-18 Elint   131 83060C
    1 14139U 83060C   07163.64774262 0.00000023  00000-0  83610-4 0    00
    2 14139  96.6588 162.8700 0001784 357.9710   2.0289 12.93732462    08
    USA 116         100 95066A
    1 23728U 95066A   08323.69802823 0.00000600  00000-0  31670-4 0    02
    2 23728  97.9290 101.5081 0307000 194.3756 165.6243 14.83044340    09
    USA 3            58 84065C
    1 15071U 84065C   08272.11992388 0.00000170  00000-0  20191-4 0    05
    2 15071  95.9105 219.2652 0005000   2.5314 357.4684 14.84533720    06
    KH 9-17 Elint    49 82041C
    1 13172U 82041C   08286.12855325 0.00000170  00000-0  21353-4 0    03
    2 13172  95.9640  82.2569 0002000  59.2568 300.7431 14.82218542    03
    USA 102          23 94017B
    1 23031U 94017B   09026.28268435 0.00000800  00000-0  32022-4 0    09
    2 23031 105.0511 266.7364 0017000 146.4138 213.5862 15.24879330    02
    NOSS 1 (D)       20 76038D
    1 08836U 76038D   09031.73055006 0.00000800  00000-0  54579-4 0    03
    2 08836  63.2925   0.1800 0916500  75.4621 284.5379 13.55481519    09
    
    
    ----- Original Message ----- 
    >
    > Ok, so I'm slow to chime in, but being an old Unix guy I wanted to share
    > this piece to make it easier if you have access to a *NIX system, a
    ...
    >
    > While the full file currently has 280 vehicles in it, this is the
    > beginning of the output. It is from Mike McCants' classfd.tle from 0500
    > 16 March 2008 CDT, and represents the very oldest 14 vehicles in the file:
    >
    > 90059U 06320.93910488
    > 11852U 07037.75716387
    > 90061U 07048.80870443
    > 90057U 07061.96014410
    > 90047U 07130.72731785
    > 14139U 07163.64774262
    > 30588U 07224.01907183
    > 90062U 07240.48781203
    > 90076U 07261.14212025
    > 90020U 07306.84635606
    > 26356U 08066.83903380
    > 96027U 08098.39106334
    > 96085U 08100.69892177
    > 90080U 08181.08833312
    >
    > This shows some vehicles are probably going to be quite challenging to
    > recover since their last updates were at the end of 2006 and the early
    > part of 2007.
    >
    > Of course, this doesn't distinguish between LEO, MEO and GEO vehicles.
    
    
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