Decay watch: June 24
Alan Pickup (alan@wingar.demon.co.uk)
Thu, 24 Jun 1999 20:58:49 +0100
Something quite bizarre has happened with the decaying Molniya rocket...
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Object: #16686 = 86- 31 D = Molniya 3-28 r2
Decay predictions:
Source Prediction made Predicted decay at Latitude Longitude
UTC UTC deg deg
SpaceCom Jun 17 01:00 Jun 23 16:44 +-4d 46.6 S 44.7 W
SpaceCom Jun 20 05:29 Jun 24 05:35 +-2d 27.7 S 139.1 E
SpaceCom Jun 21 01:35 Jun 24 05:27 +-2d 56.8 S 102.6 E
SpaceCom Jun 21 08:42 Jun 24 05:17 +-2d 60.9 S 53.9 E
SpaceCom Jun 22 16:51 Jun 24 07:40 +-1d 47.4 S 88.3 E
SpaceCom Jun 23 05:19 Jun 24 05:39 +-15h 60.2 S 84.8 E
SpaceCom Jun 23 05:19 Jun 24 05:39 +-15h 60.2 S 84.8 E
SpaceCom Jun 23 21:52 Jun 24 05:55 +-5h 56.8 S 95.8 E
SatEvo Jun 17 19:35 Jun 24 00:00 +-2d
SatEvo Jun 20 17:30 Jun 24 09:52 +-1.3d
SatEvo Jun 21 20:20 Jun 24 05:27 +-18h
SatEvo Jun 22 19:55 Jun 24 05:31 +-11h
SatEvo Jun 23 18:40 Jun 24 07:34 +-5h 61.3 S 22.8 E
SatEvo Jun 24 19:15 ! Jun 27 20:00 +-? !
Latest elset:
Moln 3-28 r2 1609 x 86 km
1 16686U 86031D 99175.70663882 .18814004 00000-0 21842-3 0 5167
2 16686 61.7514 149.4822 1053385 261.5169 86.6248 14.13539830 85181
SatEvo prediction:
Moln 3-28 r2 1548 x 86 km
1 16686U 86031D 99175.91817360 .20193621 13408-1 22677-3 0 95163
2 16686 61.7479 148.8184 1015602 261.6012 86.7760 14.22572886 85215
Moln 3-28 r2 1470 x 86 km
1 16686U 86031D 99176.19830506 .21408175 15637-1 22743-3 0 95165
2 16686 61.7429 147.9263 0967323 261.7147 87.2176 14.34218121 85256
Moln 3-28 r2 1389 x 85 km
1 16686U 86031D 99176.47611700 .22822508 18412-1 22842-3 0 95164
2 16686 61.7381 147.0257 0916571 261.8297 87.6859 14.46494934 85290
Note: Sometime before midnight UTC on June 23/24, the drag experienced
by this decayer fell sharply so that, in the course of the single orbit
beginning at 23:49 UTC, it went from running 12 seconds early against
yesterday's SatEvo prediction to running 117 seconds late! As another
posting by Daniel Deak mentions, the SpaceCom drag rate then fell
resolutely over several elsets, though it may now have stabilised.
SpaceCom's decay notices for this have dried up, too, so perhaps I'm
not the only one who's puzzled.
One clue is that the recent elsets suggest that the perigee has risen
10 km or more to around the 87 km level (relative to a spherical
Earth). I can't put this down to normal atmospheric decay or
luni-solar effects. As to when this rocket will finally decay, your
guess is probably as good as mine :)
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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
Scotland | SatEvo page: http://www.wingar.demon.co.uk/satevo/