Decay watch: 2000 Feb 6

From: Alan Pickup (alan@wingar.demon.co.uk)
Date: Sun Feb 06 2000 - 12:35:20 PST

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    #22702 = 93- 42 C = GPS 2-21 r2 (PAM-D)
    
    OIG has started to post fresh data again, including five elsets
    over the final day of this decayer and, in the past few minutes, several
    missed SpaceCom decay warnings. The final elset...
    GPS 2-21 r2      3.0  1.5  0.0  6.5 d  3.4       233 x 125 km
    1 22702U 93042C   00036.92316574  .29930517  63367-6  51302-3 0  7097
    2 22702  34.4930 339.4695 0082065 263.7476 170.9951 16.35085860152757
    ... shows it 
    running 114 seconds early on my latest prediction, which had been based 
    on elsets more than 30 hours old. SpaceCom puts the decay at Feb 5 22:56
    +-1m, near perigee on that very orbit, but I show it surviving for two
    (or at least one) further orbits with the decay just after perigee to
    the W of Australia near 32.9 S, 104.4 E at Feb 6 01:56 +-90m.
    That orbit would take it N of Perth at 01:58 UTC and NE across 
    Australia to Townsville, Queensland at 02:06. The next landfall would 
    have been near Los Angeles at 02:32. My prediction for the final 
    couple of orbits:
    GPS 2-21 r2      3.0  1.5  0.0  6.5 d  3.4       215 x 124 km
    1 22702U 93042C   00036.97136626  .46401630  98459+0  68310-3 0 97097
    2 22702  34.4918 339.1094 0069437 264.2711  94.9368 16.38553576152764
    GPS 2-21 r2      3.0  1.5  0.0  6.5 d  3.4       184 x 118 km
    1 22702U 93042C   00037.03219745  .78966994  38411+1  67600-3 0 97097
    2 22702  34.4904 338.6514 0050501 264.9370  94.4863 16.45749096152778
    
    Thanks (and commiseration's) to Ed Cannon, Jim Nix, Don Gardner and
    Wayne Hughes for the negative obs of this. Perhaps SpaceCom is/was
    correct after all :(
    
    
    #26043 = 99- 73 B = Cosmos 2368 r1
    
    This enters eclipse at far-southern latitudes and leaves eclipse near 58
    deg N while northbound at about 06h local time. I show this decaying at
    Feb 7 17:52 +-6h near 39.9 N, 78.0 W. This is in daylight while it is
    SE-bound over the NE USA, between Pittsburgh and Washington DC. SpaceCom
    puts the decay more than one orbit earlier, while over NE Australia at
    Feb 7 15:49 +-14h near 21.2 S, 148.0 E. My prediction for the final
    orbit:
    Cosmos 2368 r1   4.0  0.0  0.0  5.0 d   12       134 x 117 km
    1 26043U 99073B   00038.72199819  .73931907  44021+1  36211-3 0 91199
    2 26043  62.7863 172.5326 0012633 110.1785 249.9575 16.55232988  6638
    
    
    See http://www.wingar.demon.co.uk/satevo/dkwatch/ for more details.
    
    
    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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