Yesterdays elset for #22709 1993-44 A :
Cosmos 2258
1 22709U 93044 A 95152.36004767 .00941474 00000-0 68337-3 0 4135
2 22709 065.0200 226.3296 0056891 241.7410 117.7956 16.11558597108051
I have tried using NPOE 3.0 integration program to predict the decay
of #22709 1993-44 A. After some trial-and-error, and many hours of
computing time, I found a value of Area*Drag coefficient/Mass of
0.02182 sq.m/kg, which makes extrapolation of elset 95148.81 to
149.25, 149.43, 149.87, 150.37, 150.49, 151.55, 152.23, 152.36
have errors of less than 4 seconds. This corresponds to an accuracy
in the drag term of better than 1%, since the accumulated effect of
drag to day 152.36 is about 540 seconds. Further extrapolation indicates
a decay on the orbit starting June 07, 17:03 UT.
The residuals show a slightly increasing tendency, both linear and
quadratic terms, which could indicate a few more revolutions are possible.
My usual mathematical extrapolation fits the given elsets to better
than 1 second for each point, but I would expect NPOE to be more
accurate for extrapolation, since it uses a real atmosphere model.
NPOE Day O-C (seconds) % of drag
05/28/1995 19:34:48 148.8158308 -----------------------
05/29/1995 06:02:32 149.2517214 -3.590784 48.38%
05/29/1995 10:31:30 149.4384910 -3.982176 26.10%
05/29/1995 20:58:52 149.8742200 0.454464 -1.02%
05/30/1995 08:55:33 150.3718675 -3.195072 3.26%
05/30/1995 11:54:39 150.4962687 -1.651104 1.44%
05/31/1995 13:16:09 151.5529281 3.73248 -1.19%
06/01/1995 05:39:41 152.2359145 1.609632 -0.32%
06/01/1995 08:38:26 152.3600477 2.439936 -0.45%
You can compare the following predicted node crossings with future
elsets, to judge the accuracy of my NPOE attempt:
Semi-major axis :
06/01/1995 10:07:47 152.4220747
06/01/1995 11:37:08 152.4841245 6626.5778
06/01/1995 13:06:29 152.5461694 6626.231
06/01/1995 14:35:49 152.6082095 6625.8817
06/01/1995 16:05:09 152.6702446 6625.5296
06/01/1995 17:34:29 152.7322747 6625.1749
06/01/1995 19:03:48 152.7942999 6624.8174
06/01/1995 20:33:06 152.8563200 6624.4571
06/01/1995 22:02:24 152.9183349 6624.094
06/01/1995 23:31:42 152.9803448 6623.7279
06/02/1995 01:00:59 153.0423495 6623.3594
06/02/1995 02:30:16 153.1043490 6622.9879
06/02/1995 03:59:32 153.1663433 6622.6134
06/02/1995 05:28:48 153.2283322 6622.2356
06/02/1995 06:58:03 153.2903159 6621.8547
06/02/1995 08:27:18 153.3522941 6621.4705
06/02/1995 09:56:33 153.4142669 6621.0829
06/02/1995 11:25:47 153.4762343 6620.6918
06/02/1995 12:55:00 153.5381961 6620.2972
06/02/1995 14:24:13 153.6001523 6619.8991
06/02/1995 15:53:26 153.6621030 6619.4973
06/02/1995 17:22:38 153.7240479 6619.0917
06/02/1995 18:51:49 153.7859871 6618.6822
06/02/1995 20:21:00 153.8479206 6618.2688
06/02/1995 21:50:11 153.9098482 6617.8514
06/02/1995 23:19:21 153.9717699 6617.4299
06/03/1995 00:48:30 154.0336856 6617.0047
06/03/1995 02:17:39 154.0955953 6616.5754
06/03/1995 03:46:48 154.1574990 6616.1416
06/03/1995 05:15:56 154.2193966 6615.7034
06/03/1995 06:45:03 154.2812879 6615.2605
06/03/1995 08:14:10 154.3431730 6614.8128
06/03/1995 09:43:16 154.4050518 6614.3602
06/03/1995 11:12:22 154.4669242 6613.9026
06/03/1995 12:41:27 154.5287901 6613.4398
06/03/1995 14:10:32 154.5906495 6612.9718
06/03/1995 15:39:36 154.6525022 6612.4983
06/03/1995 17:08:40 154.7143483 6612.0192
06/03/1995 18:37:43 154.7761876 6611.5343
06/03/1995 20:06:45 154.8380200 6611.0435
06/03/1995 21:35:47 154.8998455 6610.5466
06/03/1995 23:04:48 154.9616640 6610.0434
06/04/1995 00:33:48 155.0234754 6609.5342
06/04/1995 02:02:48 155.0852796 6609.0187
06/04/1995 03:31:47 155.1470765 6608.4964
06/04/1995 05:00:46 155.2088660 6607.9669
06/04/1995 06:29:44 155.2706480 6607.4302
06/04/1995 07:58:41 155.3324225 6606.8859
06/04/1995 09:27:38 155.3941892 6606.3338
06/04/1995 10:56:34 155.4559481 6605.7737
06/04/1995 12:25:29 155.5176991 6605.2051
06/04/1995 13:54:24 155.5794421 6604.6279
06/04/1995 15:23:18 155.6411769 6604.0418
06/04/1995 16:52:11 155.7029034 6603.4463
06/04/1995 18:21:03 155.7646215 6602.8412
06/04/1995 19:49:55 155.8263311 6602.2261
06/04/1995 21:18:46 155.8880319 6601.6005
06/04/1995 22:47:36 155.9497239 6600.9641
06/05/1995 00:16:26 156.0114069 6600.3166
06/05/1995 01:45:14 156.0730807 6599.6583
06/05/1995 03:14:02 156.1347452 6598.9876
06/05/1995 04:42:49 156.1964002 6598.3043
06/05/1995 06:11:35 156.2580455 6597.6076
06/05/1995 07:40:20 156.3196810 6596.897
06/05/1995 09:09:05 156.3813064 6596.1717
06/05/1995 10:37:48 156.4429215 6595.4312
06/05/1995 12:06:31 156.5045261 6594.6746
06/05/1995 13:35:13 156.5661200 6593.9011
06/05/1995 15:03:54 156.6277030 6593.1098
06/05/1995 16:32:33 156.6892747 6592.3
06/05/1995 18:01:12 156.7508349 6591.4704
06/05/1995 19:29:50 156.8123834 6590.6199
06/05/1995 20:58:27 156.8739198 6589.7473
06/05/1995 22:27:02 156.9354438 6588.8513
06/05/1995 23:55:37 156.9969551 6587.9305
06/06/1995 01:24:10 157.0584534 6586.9843
06/06/1995 02:52:43 157.1199382 6586.0099
06/06/1995 04:21:14 157.1814091 6585.0054
06/06/1995 05:49:44 157.2428658 6583.9684
06/06/1995 07:18:12 157.3043077 6582.8966
06/06/1995 08:46:39 157.3657344 6581.7872
06/06/1995 10:15:05 157.4271452 6580.6372
06/06/1995 11:43:30 157.4885397 6579.4429
06/06/1995 13:11:53 157.5499171 6578.2006
06/06/1995 14:40:14 157.6112769 6576.9055
06/06/1995 16:08:34 157.6726181 6575.5525
06/06/1995 17:36:52 157.7339400 6574.1355
06/06/1995 19:05:09 157.7952416 6572.6472
06/06/1995 20:33:23 157.8565219 6571.0792
06/06/1995 22:01:36 157.9177796 6569.4214
06/06/1995 23:29:47 157.9790136 6567.6615
06/07/1995 00:57:55 158.0402222 6565.7859
06/07/1995 02:26:01 158.1014038 6563.7744
06/07/1995 03:54:05 158.1625563 6561.6034
06/07/1995 05:22:06 158.2236773 6559.2414
06/07/1995 06:50:04 158.2847638 6556.6469
06/07/1995 08:17:58 158.3458124 6553.7615
06/07/1995 09:45:49 158.4068185 6550.5019
06/07/1995 11:13:36 158.4677761 6546.7391
06/07/1995 12:41:18 158.5286772 6542.2569
06/07/1995 14:08:54 158.5895095 6536.6446
06/07/1995 15:36:22 158.6502528 6528.9288
06/07/1995 17:03:39 158.7108638 6515.2542
My usual method gives Ascending Node Times as
155.7665589 -0.0604255504*x -0.000324220662,*x*ln(x)
where x= 10860.18650873 -n , and n is an integer orbit number.
Although this fits the current elsets better, the .000324 value,
which is roughly proportional to atmosperic scale height, has been
about .00055 for most successful extrapolations (.0004-.0005 for
the very last days). This fully explains the (asymptotic) decay
date of 155.96, almost three days before the NPOE model prediction.
=========================================================
Bjorn_gimle@lector.kth.se == bjorn.gimle@duesenberg.se ==
== bjorn.gimle@online.dextel.se ; 59.22371 N, 18.22857 E
=========================================================
Received on Fri Jun 02 1995 - 09:07:56 UTC
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