Re: #24763 decay & geomagnetic storm

Alan Pickup (alan@wingar.demon.co.uk)
Fri, 16 May 1997 07:41:47 +0100

New elsets from OIG confirm that the decay of this object has
accelerated. The latest elset from OIG is:
Cosmos 2340 SL-6 plat                            259 x 168 km
1 24763U 97015C   97136.00176144  .03409118  84135-5  81332-3 0  1245
2 24763  62.8527 140.8016 0069350 117.6929 243.1893 16.22350669  5647

This shows it running 13 seconds late with respect to my previous SatEvo
evolution which was based on a x2.39 increase in drag from the onset of
the geomagnetic storm on the morning of the 15th. Simply changing the
factor to x2.11 produces an evolution which satisfies all but one of the
seven elsets since then with a mean error of 0.3 sec (max 0.9 sec) - the
omitted elset (at 97135.38) being clearly a "rogue".

The new evolution predicts decay around May 17.4 (ie tomorrow). However,
assuming that the atmosphere will settle down after the storm, I expect
the object to begin to run late and for the decay to be delayed a
little.

The evolution over the next few hours runs:
Cosmos 2340 SL-6 plat                            248 x 165 km
1 24763U 97015C   97136.24806380  .04798580  85156-2  98361-3 0 91248
2 24763  62.8520 139.8018 0062925 117.7378 242.9000 16.24829896  5686
Cosmos 2340 SL-6 plat                            236 x 163 km
1 24763U 97015C   97136.49403569  .05639098  14932-1  99249-3 0 91245
2 24763  62.8511 138.8000 0055774 117.7828 242.7833 16.27376086  5728
Cosmos 2340 SL-6 plat                            223 x 160 km
1 24763U 97015C   97136.73958374  .07094341  26155-1  10156-2 0 91248
2 24763  62.8502 137.7959 0047576 117.8281 242.6535 16.30468675  5766
Cosmos 2340 SL-6 plat                            205 x 156 km
1 24763U 97015C   97136.98459689  .10061548  63312-1  96741-3 0 91248
2 24763  62.8488 136.7888 0037656 117.8735 242.5082 16.34567218  5809
Cosmos 2340 SL-6 plat                            178 x 147 km
1 24763U 97015C   97137.22883215  .20318053  30922+0  74220-3 0 91246
2 24763  62.8467 135.7775 0023982 117.9193 242.3235 16.41324366  5841
Cosmos 2340 SL-6 plat                            167 x 142 km
1 24763U 97015C   97137.28969715  .28919477  67085+0  68945-3 0 91244
2 24763  62.8459 135.5236 0019108 117.9308 242.2626 16.44251614  5857
Cosmos 2340 SL-6 plat                            150 x 134 km
1 24763U 97015C   97137.35042352  .56230724  28305+1  67615-3 0 91249
2 24763  62.8447 135.2690 0012469 117.9424 242.1839 16.49011674  5868

I plan to post another analysis this (UK) evening.

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    | Royal Observatory: A.Pickup@roe.ac.uk +44 (0)131 668 8224