Re: Decay watch: Long March and Dispenser

Alan Pickup (alan@wingar.demon.co.uk)
Mon, 21 Sep 1998 21:53:42 +0100

The Long March rocket lasted much longer than I predicted, with the
final elset:
Iridm 3 CSL02 r 10.0  3.0  0.0  4.0 d            118 x 102 km
1 25433U 98048C   98264.15805988  .14191064 -16451-5  37548-4 0  1407
2 25433  86.3345 231.9511 0012918  24.4665 335.9914 16.61258020  5086

Decay was likely near perigee on this orbit at about September 21.16
(~03:50 UTC). Not for the first time, the drag rate appears to have
fallen sharply over the final orbits as the atmospheric flow regime
changed.

             ------------------------------------

The latest elset for the Smart Dispenser shows it 13 seconds late on
yesterdays evolution.
Iridm 3 S/D      5.0  2.0  0.0  5.5 d            264 x 164 km
1 25434U 98048D   98264.57019556  .03196201 -13041-5  75431-3 0  1121
2 25434  86.3035 231.6345 0075685  26.9777 333.5783 16.21962352  5136

My new analysis indicates decay at September 23.35 +-0.35day.
Predicted elsets:
Iridm 3 S/D      5.0  2.0  0.0  5.5 d            249 x 162 km
1 25434U 98048D   98265.00161983  .04193438  72191-2  83308-3 0 91120
2 25434  86.3023 231.3871 0065782  25.0995 335.2189 16.25280427  5200
Iridm 3 S/D      5.0  2.0  0.0  5.5 d            223 x 157 km
1 25434U 98048D   98265.55488347  .06212735  20356-1  78908-3 0 91125
2 25434  86.3003 231.0678 0050305  22.6761 337.5454 16.30840894  5294
Iridm 3 S/D      5.0  2.0  0.0  5.5 d            187 x 147 km
1 25434U 98048D   98266.04464990  .13787469  13354+0  59059-3 0 91121
2 25434  86.2973 230.7823 0030660  20.5102 339.6126 16.39496148  5371
Iridm 3 S/D      5.0  2.0  0.0  5.5 d            143 x 128 km
1 25434U 98048D   98266.28810716  .56761952  28253+1  49865-3 0 91123
2 25434  86.2936 230.6382 0012216  19.4189 340.6274 16.51480627  5418

Alan
-- 
 Alan Pickup | COSPAR 2707:   55d53m48.7s N   3d11m51.2s W   156m asl
 Edinburgh   | Home:   alan@wingar.demon.co.uk    +44 (0)131 477 9144
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