Decay watch: May 28

Alan Pickup (alan@wingar.demon.co.uk)
Fri, 28 May 1999 22:52:07 +0100

SpaceCom has issued another decay notice for the Titan, but are still
keeping the elsets secret.
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Object: #25745 = 99- 28 B = USA 144 Titan 4 r

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

SpaceCom   May 24 21:58     Jun  2 11:36 +-5d        63.4 S    94.0 W
SpaceCom   May 26 06:28     Jun  1 14:00 +-4d        47.1 N     3.3 W
SpaceCom   May 28 11:26     Jun  1 11:29 +-2d        19.2 N   172.6 E

SatEvo     May 25 12:00     Jun  3       +-3d
SatEvo     May 27 19:00     Jun  1 23:00 +-1.4d (but see note below)
SatEvo     May 29 21:25     Jun  1 02:43 +-20h

Latest elset by Pierre Neirinck:
USA 144 Titan 4 r                                261 x 194 km
1 25745U 99028  B 99147.90363690  .01450000  00000-0  72065-3 0    03
2 25745  63.3550  81.6250 0050747 168.9210 191.1912 16.17077649    01

SatEvo prediction:
USA 144 Titan 4 r                                247 x 188 km
1 25745U 99028  B 99149.07725070  .01876379  16497-2  71594-3 0 90002
2 25745  63.3537  76.9751 0044703 168.9502 191.1483 16.20929681   197
USA 144 Titan 4 r                                240 x 185 km
1 25745U 99028  B 99149.50887436  .02119384  21362-2  71360-3 0 90000
2 25745  63.3532  75.2580 0042111 168.9611 191.1316 16.22650017   265
USA 144 Titan 4 r                                231 x 180 km
1 25745U 99028  B 99150.06309263  .02561770  33063-2  70901-3 0 90001
2 25745  63.3523  73.0463 0038333 168.9753 191.1090 16.25226423   351

Note: Pierre comments that the elset posted yesterday by Rainer, and 
copied in my previous note, contained an average drag value for the
period of the analysis, rather than the instantaneous value for the 
epoch. The latter is estimated by Pierre as 0.0125 rather than the 
0.01096472 as posted. Using this value of drag, my prediction yesterday 
for decay on June 1 at 23:00 UTC would have jumped forwards to June 1 
at 05:00. The drag value in Pierre's latest elset is his (new) 
instantaneous value - the average value over the period of analysis is 
0.01228, in agreement with Rainer's posting today. Again, the SatEvo 
prediction is based entirely on Pierre's elset.
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Object: #25683 = 99- 20 B = Landsat 7 Delta r

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

SpaceCom   May 26 20:46     May 30 20:26 +-2d        25.7 S   102.5 W
SpaceCom   May 28 19:51     May 30 17:37 +-1d        52.4 S    75.7 W

SatEvo     May 25 19:30     Jun  1 00:00 +-1.2d
SatEvo     May 26 18:00     May 31 10:00 +-1d
SatEvo     May 27 18:00     May 31 09:00 +-0.8d
SatEvo     May 28 21:40     May 31 03:50 +-12h

Latest elset:
Lndst7 Delta r   5.9  2.4  0.0  5.0 d            301 x 144 km
1 25683U 99020B   99148.78883613  .03311436  92313-5  24227-3 0  1311
2 25683 107.5582 274.1139 0118401 242.5428 116.4437 16.18884472  6745

SatEvo prediction:
Lndst7 Delta r   5.9  2.4  0.0  5.0 d            292 x 144 km
1 25683U 99020B   99149.03586157  .03770575  37045-2  25017-3 0 91311
2 25683 107.5576 274.7731 0112487 241.9474 116.9105 16.20701072  6782
Lndst7 Delta r   5.9  2.4  0.0  5.0 d            272 x 141 km
1 25683U 99020B   99149.52910790  .04456379  58402-2  23672-3 0 91318
2 25683 107.5561 276.0947 0099422 240.7535 118.2487 16.24733741  6867
Lndst7 Delta r   5.9  2.4  0.0  5.0 d            249 x 138 km
1 25683U 99020B   99150.02101606  .05646273  11290-1  22263-3 0 91316
2 25683 107.5544 277.4209 0084167 239.5551 119.6108 16.29636540  6946

Note: The latest elset has this running 17 seconds early against my
previous prediction.
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Alan
-- 
 Alan Pickup | COSPAR 2707:  55d53m48.7s N  3d11m51.2s W   156m asl
 Edinburgh   | Tel: +44 (0)131 477 9144     Fax: +44 (0)870 0520750
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