Decay watch: 2000 Feb 19

From: Alan Pickup (alan@wingar.demon.co.uk)
Date: Sat Feb 19 2000 - 11:56:51 PST

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    #25769 = 99- 30 B = Starshine
    
    Apologies for this long-delayed update to yesterday's decay. SpaceCom's
    final notice gives the decay at Feb 18 15:45 UTC +-22m at 34.6 S, 51.1
    W. My estimate is Feb 18 15:09 -1+45m near the equator at 170.2 E.
    
    The final two elsets for this (one the former still not in OIG's
    database) are:
    Starshine        1.0  0.0  0.0  9.0 d 0.30       145 x 143 km
    1 25769U 99030B   00049.48035817  .12890540  12629-4  20493-3 0  3425
    2 25769  51.5812   6.2360 0002000 269.4929  90.4903 16.48315797 42094
    Starshine        1.0  0.0  0.0  9.0 d 0.30       166 x 88 km
    1 25769U 99030B   00049.60150974  .22193012  13358-4  55675-4 0  3434
    2 25769  51.3223   5.7104 0059441  55.6569 304.3326 16.54690199 42112
    
    Starshine clearly survived the northbound equator crossing and possible
    decay over Lagos that I had warned of in my final pre-decay posting.
    Indeed, I understand that SpaceCom's last sensing of the satellite
    occurred at 15:08 UTC as it was approaching its southbound equator
    crossing over the W Pacific. The final elset, presumably incorporating
    this fix but issued many hours later, is obviously in error since it
    implies that Starshine's apogee had risen considerably, while (to reach
    the Pacific) it would have had to survive a very deep passage over N
    Africa. Not surprisingly, I find it impossible to link this elset with
    the ones that came before.
       When such an eccentric elset (using both meanings of the term) has
    been issued before, I have taken it as evidence that the object was
    suffering very high drag in the early stages of reentry at the time it
    was observed. If this was the case with Starshine, then I feel justified
    in placing the decay time at 15:09 UTC, as it crossed the equator.
    However, it is possible that it survived beyond this point, and perhaps
    to South America and beyond as both SpaceCom and Harro Zimmer suggest.
    If this did reach South America, it would have overflown Pategonia at
    15:37 UTC, but with the Sun high in a midday sky.
    
    More 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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    This archive was generated by hypermail 2b29 : Sat Feb 19 2000 - 11:58:45 PST