Re: Decay update: Iridium 15 Delta 2 r

Alan Pickup (alan@wingar.demon.co.uk)
Sat, 28 Mar 1998 23:13:28 +0000

There is little more than a day left for this decaying Delta 2 rocket.
The latest elset at the time of posting is:

Iridm 15 Delta r 5.9  2.4  0.0  5.6 d            223 x 182 km
1 24874U 97034F   98087.63829283  .02696554 -12901-5  75032-3 0  3328
2 24874  82.6966 276.7622 0031027  90.3077 270.1674 16.26435285 40884

Compared with the "9324" SatEvo evolution I posted yesterday, this shows
it running 8.7 seconds late. In fact, the drag rate has been steady
since this morning while the perigee has fallen by 4 km, suggesting that
the atmospheric isobars have been falling with the Delta.

My current prediction is for decay at March 30.3 (+-0.3d), though for
this to happen the drag must increase again very soon.

Predicted elset to decay:

Iridm 15 Delta r 5.9  2.4  0.0  5.6 d            213 x 177 km
1 24874U 97034F   98088.00714436  .03760807  80491-2  85200-3 0 93329
2 24874  82.6957 276.3428 0027339  88.7916 271.5216 16.28980360 40943
Iridm 15 Delta r 5.9  2.4  0.0  5.6 d            206 x 174 km
1 24874U 97034F   98088.25271667  .04487928  12057-1  85564-3 0 93326
2 24874  82.6950 276.0626 0024579  87.7789 272.5025 16.30994206 40983
Iridm 15 Delta r 5.9  2.4  0.0  5.6 d            195 x 168 km
1 24874U 97034F   98088.55920312  .06023248  23456-1  85826-3 0 93326
2 24874  82.6939 275.7117 0020622  86.5104 273.7254 16.34164481 41036
Iridm 15 Delta r 5.9  2.4  0.0  5.6 d            183 x 161 km
1 24874U 97034F   98088.80389643  .08518500  49782-1  85489-3 0 93327
2 24874  82.6927 275.4301 0016807  85.4929 274.6990 16.37645235 41073
Iridm 15 Delta r 5.9  2.4  0.0  5.6 d            165 x 150 km
1 24874U 97034F   98089.04794528  .14946296  15351+0  55521-3 0 93327
2 24874  82.6909 275.1475 0011835  84.4720 275.6630 16.43086561 41111
Iridm 15 Delta r 5.9  2.4  0.0  5.6 d            151 x 140 km
1 24874U 97034F   98089.16958970  .25679104  58529+0  42719-3 0 93325
2 24874  82.6891 275.0055 0008311  83.9594 276.1353 16.47760933 41138
Iridm 15 Delta r 5.9  2.4  0.0  5.6 d            138 x 131 km
1 24874U 97034F   98089.23024934  .44604739  21712+1  40238-3 0 93329
2 24874  82.6877 274.9343 0005800  83.7022 276.3639 16.51783332 41147

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
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