Decay watch: 2000 Mar 22

From: Alan Pickup (alan@wingar.demon.co.uk)
Date: Wed Mar 22 2000 - 15:01:21 PST

  • Next message: John Gardner: "Re: Decay watch: 2000 Mar 22"

    #11331 = 79- 32 A = Cosmos 1093
    
    My latest estimate is for decay at Mar 23 17:39 UTC +-5h near 18.0 S,
    13.3 E, while northbound just NW of Australia. If it survives, it passes
    near Jakarta, Indonesia, at 17:42 UTC, E of Hong Kong at 17:49 and E of
    Beijing, China, at 17:53. The following southbound track takes it over
    the E USA from Lake Huron at 18:16 to Charleston, S Carolina, at 18:19.
    My prediction for the final two revs:
    Cosmos 1093      5.0  1.5  0.0  5.4 v   11       151 x 144 km
    1 11331U 79032A   00083.61722543  .25399730  63657+0  52022-3 0 94117
    2 11331  81.1827 202.5967 0004767 274.8357  85.1098 16.46949701154423
    Cosmos 1093      5.0  1.5  0.0  5.4 v   11       139 x 134 km
    1 11331U 79032A   00083.67791950  .47854705  25171+1  49116-3 0 94113
    2 11331  81.1813 202.5110 0003538 274.5889  85.3707 16.51084707154432
    SpaceCom predicts a later decay, at Mar 23 21:56 +-16h at 55.2 S, 39.5
    E.
    
    #15977 = 85- 74 A = Molniya 1-64
    
    The final published elset is:
    Molniya 1-64                                     839 x 94 km
    1 15977U 85074A   00082.11078701  .99999999  71988-5  17209-2 0  1799
    2 15977  61.9337 136.1460 0544269 268.8111  85.0592 15.33209864 53837
    
    SpaceCom reports decay at Mar 22 05:36 +-7m at 39.1 S, 153.1 W, while I
    get Mar 22 05:29 -10m+90m at 52.2 S, 169.6 W.
    
    This kept to within a minute of my SatEvo prediction for the latter half
    of the 21st, but then drifted sharply later so that the eventual decay
    came later than SpaceCom or I anticipated. Once again, it is tempting to
    suggest that the Molniya's drag coefficient dropped sharply, perhaps at
    the perigee at about 23:05 UTC, when the stresses caused it to shed one
    or more of its "wings". I now calculate the following elsets for its
    final revs:
    Molniya 1-64                                     832 x 87 km
    1 15977U 85074A   00082.11076741 1.86501428  17844+1  15767-2 0 91796
    2 15977  61.9337 136.1461 0544285 268.8111  84.9510 15.35478789 53830
    Molniya 1-64                                     675 x 86 km
    1 15977U 85074A   00082.17556616 2.37350187  39623+1  16416-2 0 91798
    2 15977  61.9256 135.9021 0436025 268.8389  86.1640 15.62478274 53846
    Molniya 1-64                                     466 x 84 km
    1 15977U 85074A   00082.23916341 3.81882714  13442+2  18733-2 0 91792
    2 15977  61.9152 135.6516 0287347 268.8676  87.8394 15.99878930 53855
    Like SpaceCom, I think decay is most likely a little beyond perigee on
    the penultimate of these orbits, while it was NE-bound over the S
    Pacific. There is a possibility, though, that it survived to reenter on
    the approach to the following perigee at 06:52 UTC.
    
    
    #20919 = 90- 93 B = Inmarsat 2-1 Delta 2 rocket
    
    SpaceCom is predicting this decay for Mar 25 20:33 +-2d at 23.6 N, 34.4
    E while I calculate Mar 25 23:46 +-19h. The latest elset is:
    Inmarsat 2-1 r   5.9  2.4  0.0  5.0 v   14       261 x 215 km
    1 20919U 90093B   00082.64219889  .01586688 -12792-4  11260-2 0  5872
    2 20919  24.7094  82.5584 0035440 105.1690 255.2707 16.13256671511967
    
    
    More details at http://www.wingar.demon.co.uk/satevo/dkwatch/
    
    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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