Decay watch: Iridium 19 Delta 2 rocket (and others)

Alan Pickup (alan@wingar.demon.co.uk)
Wed, 15 Apr 1998 19:55:51 +0100

The current published elset for the Iridium 19 Delta 2 rocket is:

Iridm 19 Delta r 5.9  2.4  0.0  5.6 d            231 x 186 km
1 24970U 97056F   98105.64081303  .02234011 -13263-5  74239-3 0  2701
2 24970  83.5881 265.4891 0034772 285.9210  73.8285 16.24102168 31471

This has it 143 seconds late on the predicted evolution I posted two
days ago. The drag it meets has climbed more slowly than I expected,
possibly because the atmosphere has been settling down as solar activity
has subsided from its remarkably high level of a week ago. On the 9th,
for example, the SESC sunspot number approached 200 - a level typical of
a strong sunspot maximum.

Not surprisingly, my predicted decay date has slipped and now stands at
April 17.8 +-0.4d. Predicted elsets:
Iridm 19 Delta r 5.9  2.4  0.0  5.6 d            224 x 182 km
1 24970U 97056F   98106.01024888  .02880543  44389-2  81666-3 0 92705
2 24970  83.5874 265.1214 0031610 284.3775  75.2716 16.26191884 31533
Iridm 19 Delta r 5.9  2.4  0.0  5.6 d            212 x 177 km
1 24970U 97056F   98106.50209041  .03773095  82690-2  82413-3 0 92707
2 24970  83.5862 264.6300 0026828 282.3152  77.3846 16.29419796 31616
Iridm 19 Delta r 5.9  2.4  0.0  5.6 d            193 x 167 km
1 24970U 97056F   98107.05402990  .06089158  24065-1  82963-3 0 92700
2 24970  83.5844 264.0752 0020153 279.9873  79.7853 16.34637514 31708
Iridm 19 Delta r 5.9  2.4  0.0  5.6 d            163 x 148 km
1 24970U 97056F   98107.54265231  .15514578  17928+0  51001-3 0 92705
2 24970  83.5812 263.5792 0011336 277.9069  81.9645 16.43754236 31782

The Iridium 51 Long March (CZ-2C) rocket is now predicted to re-enter on
April 24. Joining the mass-suicide of Iridium rockets is the Iridium 43
Delta 2 rocket which I now expect to decay about April 25. The latter
enters the Earth's shadow near latitude 56 deg N during local evening
and exits over Antarctica.

Alan
-- 
 Alan Pickup | COSPAR site 2707:   55d53m48.7s N   3d11m51.2s W    156m asl
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