Re: Decay watch: Iridium Long March rocket

Alan Pickup (alan@wingar.demon.co.uk)
Mon, 19 Jan 1998 22:15:10 +0000

After a long wait for a recent elset, this is the latest..
Iridm CZ-2C r   10.0  3.0  0.0  3.0 d            210 x 143 km
1 25079U 97077C   98019.65751104  .05305625 -12563-5  21510-3 0  1329
2 25079  86.2676  99.0023 0051052 356.6858   3.4125 16.36129770  6673
...which is 27 late against the "9124" SatEvo evolution I posted
previously.

My current prediction is for decay at January 20.33 +-0.1 day.

Predicted elsets:
Iridm CZ-2C r   10.0  3.0  0.0  3.0 d            193 x 139 km
1 25079U 97077C   98019.90186326  .09100965  52230-1  25732-3 0 91328
2 25079  86.2663  98.8579 0040840 355.6003   4.3639 16.40022863  6711
Iridm CZ-2C r   10.0  3.0  0.0  3.0 d            187 x 138 km
1 25079U 97077C   98019.96286276  .10204638  69577-1  25768-3 0 91324
2 25079  86.2659  98.8217 0037864 355.3283   4.6365 16.41196945  6728
Iridm CZ-2C r   10.0  3.0  0.0  3.0 d            182 x 137 km
1 25079U 97077C   98020.02381603  .11695876  94762-1  25863-3 0 91322
2 25079  86.2655  98.7855 0034635 355.0561   4.9098 16.42527034  6735
Iridm CZ-2C r   10.0  3.0  0.0  3.0 d            175 x 135 km
1 25079U 97077C   98020.08471638  .13806941  13784+0  26024-3 0 91328
2 25079  86.2650  98.7492 0031076 354.7835   5.1842 16.44071913  6746
Iridm CZ-2C r   10.0  3.0  0.0  3.0 d            168 x 132 km
1 25079U 97077C   98020.14555430  .17066164  22196+0  26352-3 0 91328
2 25079  86.2644  98.7128 0027057 354.5106   5.4598 16.45934036  6755
Iridm CZ-2C r   10.0  3.0  0.0  3.0 d            158 x 129 km
1 25079U 97077C   98020.20631495  .22890922  42718+0  27126-3 0 91326
2 25079  86.2636  98.6764 0022332 354.2372   5.7371 16.48322374  6766
Iridm CZ-2C r   10.0  3.0  0.0  3.0 d            145 x 124 km
1 25079U 97077C   98020.26697095  .37043764  12244+1  29490-3 0 91328
2 25079  86.2626  98.6400 0016304 353.9632   6.0172 16.51803458  6774

Re-entry is most likely near the following northbound equator crossing
at 07:51 UTC at 139 deg W longitude. However, the uncertainty (0.1 day =
2.5 hours) is such that re-entry is possible on the final orbit above
which takes it across the equator at 06:24 UTC at 117 deg W, then just E
of Los Angeles at 06:32 UTC moving almost due N towards Calgary in
Canada at 06:36 UTC. Remember that 06:32 UTC on the 20th is 22:32 PST on
the 19th.

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