Decay watch: 2000 Aug 15

From: Alan Pickup (alan@wingar.demon.co.uk)
Date: Tue Aug 15 2000 - 12:56:11 PDT

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    I have updated my Decay Watch page at
          http://www.wingar.demon.co.uk/satevo/dkwatch/
    with more about the following decayers.
    
    #13967 = 83- 25 D = Molniya 1-57 r2
    
    Current decay estimates:
       SpaceCom: Aug 16 10:29 +-13h       25.6 S    86.9 W
       SatEvo:   Aug 16 11:55 +-6h        31.4 S   113.7 W
    
    Latest elset:
    Molniya 1-57 r2                                  694 x 98 km
    1 13967U 83025D   00228.55868953  .24806888  87139-5  30931-3 0   150
    2 13967  62.2634  52.5932 0440117 298.3966  57.3725 15.57156959150870
    
    The latest elset shows this running 12 sec late against yesterday's
    prediction. I estimate that this will decay after perigee on the
    following orbit:
    Molniya 1-57 r2                                  291 x 91 km
    1 13967U 83025D   00229.44132905  .93268556  17932+1  46687-3 0 90153
    2 13967  62.2386  49.1198 0152173 298.7091  59.7699 16.30721388151014
    This puts it on a northbound track over the E Pacific. If it stays in
    orbit a little longer, there is a pass over the E coast of the USA from
    Tampa, Florida, at 12:11 UTC to Boston, Mass, at 12:16.
    _____________________________________________________________________
    
    #24321 = 96- 56 C = GPS 2-27 Delta 2 r2
    
    Final decay estimates:
       SpaceCom: Aug 15 07:22 +-2h        12.0 S    86.8 W
       SatEvo:   Aug 15 14:29 +-4h        21.5 N   110.9 E
    
    Final elsets:
    GPS 2-27 Delta 2 r2                              441 x 131 km
    1 24321U 96056C   00228.02104329 -.99999999 -22473-5 -19288-1 0  7660
    2 24321  34.7878 151.0547 0232477  82.5767 283.3847 15.95719254 86089
    GPS 2-27 Delta 2 r2                              513 x 125 km
    1 24321U 96056C   00228.10367355  .99999999  11120-5  65754-2 0  7674
    2 24321  34.7505 150.5383 0290064  86.4898  32.5466 15.84135389 86093
    
    SpaceCom certainly had its problems with this decayer and settled on a
    decay time that I think is too early by several hours. The two final
    elsets suggest that this was running only 13 and 8 seconds early
    respectively against the prediction I posted yesterday, but the elsets
    imply a decrease in mean motion that cannot be correct. My analysis
    discards the penultimate elset, with its extreme negative drag. I show
    this as decaying while southbound to the W of Hong Kong on a path that
    would carry it over the Philippines. My predicted elset for that orbit
    is:
    GPS 2-27 Delta 2 r2                              256 x 111 km
    1 24321U 96056C   00228.58005642  .92645582  21682+1  88485-3 0 97656
    2 24321  34.7636 147.0420 0110443  90.2054 271.0602 16.33434216 86177
    
    
    Alan
    -- 
     Alan Pickup | COSPAR 2707:  55d53m48.7s N  3d11m51.2s W   156m asl
     Edinburgh   | Tel: +44 (0)131 477 9144     Fax: +44 (0)870 0520750
     Scotland    | SatEvo page:   http://www.wingar.demon.co.uk/satevo/
    
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