Decay watch: 2000 Dec 31

From: Alan Pickup (alan@wingar.demon.co.uk)
Date: Sun Dec 31 2000 - 03:18:31 PST

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    My last Decay Watch update of the Millennium...
    
    _____________________________________________________________________
    Object: #4584 = 70- 85 B = Meteor 1-6 rocket
    
    Decay predictions:
    Source   Prediction made    Predicted decay at      Latitude Longitude
                   UTC                UTC                  deg      deg
    SpaceCom   Dec 30 11:14     Jan  1 11:16 +-1d        71.6 S    66.1 W
    SatEvo     Dec 31 10:40     Jan  1 13:07 +-7h         0.0      57.3 E
    
    Latest elset:
    Meteor 1-6 r     3.8  2.6  0.0  5.1 v   11       179 x 174 km
    1 04584U 70085B   00366.32883927  .03441118 -94724-6  44021-3 0  4767
    2 04584  81.1534 357.0100 0003770 124.7577 235.3989 16.35937199654503
    
    SatEvo prediction: See my Decay Watch page - prediction ends...
    Meteor 1-6 r     3.8  2.6  0.0  5.1 v   11       140 x 138 km
    1 04584U 70085B   01001.36523949  .16865268  25708+0  20691-3 0 94767
    2 04584  81.1486 355.5560 0001975 120.5908 239.4287 16.50095385654672
    Meteor 1-6 r     3.8  2.6  0.0  5.1 v   11       134 x 132 km
    1 04584U 70085B   01001.42584143  .23815729  53991+0  19958-3 0 94761
    2 04584  81.1478 355.4698 0001684 120.3437 239.6729 16.52506804654685
    Meteor 1-6 r     3.8  2.6  0.0  5.1 v   11       124 x 122 km
    1 04584U 70085B   01001.48633443  .38258321  76974+0  19005-3 0 94769
    2 04584  81.1467 355.3833 0001260 120.0961 239.9164 16.56198816654693
    
    Note: The latest elset shows this running 0.7 sec late against the 
    prediction I posted yesterday. My current estimate is for this to 
    decay near the northbound equator crossing at the end of the final
    predicted rev, above. This places it over the western Indian Ocean.
    I note that that rev carries it southbound in eclipse over the 
    western USA from near Spokane, Washington, at 12:12 UTC to the 
    California-Mexico border at 12:16. There are earlier southbound 
    passes over the USA within the window of uncertainty for the decay.
    _____________________________________________________________________
    Object: #25529 = 98- 66 C = Iridium 85
    
    Final decay analyses:
    Source   Prediction made    Predicted decay at      Latitude Longitude
                   UTC                UTC                  deg      deg
    SpaceCom   Dec 30 20:53     Dec 30 20:45 +-1h        60.3 S   167.8 W
    SatEvo     Dec 31 09:45     Dec 30 20:40 +-40m       58.6 S   167.5 W
    
    Final elset:
    Iridium 85 tum   4.0  1.8  0.0  6.0 d  9.3       150 x 140 km
    1 25529U 98066C   00365.74996778  .23202093 -11755-5  38608-3 0  8671
    2 25529  85.9684 248.8024 0007841 176.2789 183.8690 16.47824324120103
    
    Note: The final elset has this 20 sec late against my final pre-decay 
    prediction. I was caught out by how much this decay slipped over the 
    latter orbits - more than I can explain by any expected decrease in drag
    coefficient as it dropped into the atmospheric transition flow region.
    In the end, my best fit gives a predicted final elset of:
    Iridium 85 tum   4.0  1.8  0.0  6.0 d  9.3       132 x 124 km
    1 25529U 98066C   00365.81054454  .59309281  20663+1  37547-3 0 98673
    2 25529  85.9666 248.7630 0005746 176.0056 183.9989 16.54291319120115
    Like SpaceCom, I estimate that this decayed while northbound over the
    S Pacific.
    _____________________________________________________________________
    
    
    Alan
    -- 
    Alan Pickup / COSPAR 2707:  55d53m48.7s N   3d11m51.2s W      156m asl
    Edinburgh  / SatEvo & elsets:    http://www.wingar.demon.co.uk/satevo/
    Scotland  / Decay Watch: http://www.wingar.demon.co.uk/satevo/dkwatch/
             *
    
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