Decay watch: February 13

Alan Pickup (alan@wingar.demon.co.uk)
Sat, 13 Feb 1999 16:50:26 +0000

Object: #16187 = 85- 99 A = Molniya 1-65

Decay predictions:
Source   Prediction made    Predicted decay at      Latitude Longitude
               UTC                UTC                  deg      deg

SpaceCom   Feb 11 10:12     Feb 13 08:19 +-1d         61.6 S   135.3 E
SpaceCom   Feb 12 09:58     Feb 13 10:13 +-15h        61.7 S    98.6 E
SpaceCom   Feb 13 01:43     Feb 13 02:14 +-34m        61.7 S   133.8 E
SpaceCom   Feb 13 13:03     Feb 13 15:19 +-2h         61.2 S    35.3 E
SpaceCom   Feb 13 15:31     Feb 13 15:21 +-21m        59.1 S    48.2 E

SatEvo     Feb 11 20:15     Feb 13 11:53 +-9h         61 S      80   E
SatEvo     Feb 12 20:15     Feb 13 13:29 +-5h         61.7 S    56.9 E
SatEvo     Feb 13 15:50     Feb 13 15:16 +-15m        61.3 S    34.2 E

Final elset:
Molniya 1-65                                     495 x 62 km
1 16187U 85099A   99044.60109982  .99999999  87705-5  49840-3 0  2844
2 16187  61.6816 124.9005 0325274 271.0112 158.5867 15.98710463 98248

Note: The true drag term on the above elset was probably close to 5.3, 
rather than the ceiling value of 0.99999999 quoted. I am certain 
that the Molniya decayed near perigee on this orbit, one orbit later 
than I predicted yesterday. SatEvo did reasonably well with this, and 
rather better than SpaceCom who seemed convinced that it had decayed 
much earlier today. One hour after their premature announcement, 
SpaceCom generated a further elset showing the Molniya running only 
4 seconds late on the prediction I posted here yesterday - pretty good 
considering that the orbital period had decreased by ~800 seconds 
since the last elset I had used in my analysis. The decay point is/was 
over the Southern Ocean, about 3,500 km SSE of the Cape of Good Hope, 
S Africa.
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Object: #19771 = 89- 4 E = Gorizont 17 aux motor

Decay predictions:
Source   Prediction made    Predicted decay at      Latitude Longitude
               UTC                UTC                  deg      deg

SpaceCom   Feb 11 15:15     Feb 15 11:49 +-18h        46.4 N    41.6 W
SpaceCom   Feb 12 04:41     Feb 15 05:01 +-2d         42.6 S   106.5 W
SpaceCom   Feb 13 04:45     Feb 15 05:59 +-1d         27.8 N   111.7 E

SatEvo     Feb 11 20:15     Feb 16.0 +-0.9d
SatEvo     Feb 12 20:50     Feb 15 11:29 +-15h        22 N     101 W
SatEvo     Feb 13 16:40     Feb 15 06:56 +-8h         24 N      29 W

Current elset:
Gorizont 17 aux motor                            544 x 136 km
1 19771U 89004E   99044.53745393  .09108778  10499-4  62903-3 0  4918
2 19771  46.3632 205.2789 0303577  23.1531 338.2316 15.76669752162788

SatEvo prediction:
Gorizont 17 aux motor                            480 x 134 km
1 19771U 89004E   99045.04245996  .12572225  18941-1  67850-3 0 94917
2 19771  46.3600 202.3536 0259138  26.0806 335.2023 15.88403213162863
Gorizont 17 aux motor                            402 x 131 km
1 19771U 89004E   99045.54339808  .16814201  42631-1  68068-3 0 94910
2 19771  46.3559 199.3980 0203963  29.0388 332.0807 16.02837595162942
Gorizont 17 aux motor                            287 x 126 km
1 19771U 89004E   99046.03888917  .31606477  25346+0  72207-3 0 94918
2 19771  46.3498 196.4010 0122250  32.0391 328.6984 16.24738475163021


Note: The latest elset has this 44 sec early on yesterday's prediction.
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Object: #13103 = 82- 6 C = OPS 2849 deb

Decay predictions:
Source   Prediction made    Predicted decay at      Latitude Longitude
               UTC                UTC                  deg      deg

SpaceCom   Feb 12 13:04     Feb 19 10:40 +-4d        54.5 S    91.1 E

SatEvo     Feb 12 19:40     Feb 21.1 +-3d

Note: No further elsets have been issued since that for 99041.17.
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Alan
-- 
 Alan Pickup | COSPAR 2707:   55d53m48.7s N   3d11m51.2s W   156m asl
 Edinburgh   | Home:   alan@wingar.demon.co.uk    +44 (0)131 477 9144
 Scotland    | SatEvo page:     http://www.wingar.demon.co.uk/satevo/