Re: Decay watch: February 21
Alan Pickup (alan@wingar.demon.co.uk)
Sun, 21 Feb 1999 23:34:41 +0000
The SatEvo decay list I posted earlier today was, of course, issued
on February 21 and not 20 as stated - apologies.
The final(?) word on the Soyuz rocket:
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Object: #25633 = 99- 7 B = Soyuz TM-29 Soyuz r
Decay predictions:
Source Prediction made Predicted decay at Latitude Longitude
UTC UTC deg deg
SpaceCom Feb 20 13:48 Feb 21 20:54 +-19h 50.8 S 35.6 E
SpaceCom Feb 20 19:52 Feb 21 19:01 +-14h 3.8 N 43.4 W
SpaceCom Feb 21 06:57 Feb 21 18:35 +-8h 46.7 N 156.8 W
SpaceCom Feb 21 12:13 Feb 21 18:05 +-4h 40.3 S 112.0 E
SpaceCom Feb 21 16:08 Feb 21 18:04 +-1h 42.7 S 107.5 E
SpaceCom Feb 21 18:21 Feb 21 18:04 +-28m 42.4 S 108.0 E
SatEvo Feb 20 13:55 Feb 21 16:03 +-9h 0 3.7 E
SatEvo Feb 21 10:00 Feb 21 16:03 +-4h 0 3.7 E
SatEvo Feb 21 19:35 Feb 21 16:47 +-1h 0 172.6 E
Final elset:
Soyuz TM-29 Soyuz r 147 x 141 km
1 25633U 99007B 99052.63890138 .20865573 12602-4 32101-3 0 157
2 25633 51.6404 215.9489 0004503 111.8831 248.2713 16.48276255 243
Note: The last elset shows it running 8 seconds late on my final
prediction which was based on elsets issued more than 19 hours before.
The published elset for the preceding orbit had it only 0.5 seconds
late, so SatEvo had been performing very well until that point. The
indication is that the drag increased less than expected near the end,
another indication that SatEvo must still be improved to handle the
transition in atmospheric flow regime which the rocket could have
encountered about that time. A fit through the final elsets leads to
decay near a northbound equator crossing over the Pacific. If it had
survived this, as SpaceCom says it did, then it would have overflown the
length of southern Canada on the next orbit and I would have expected a
corresponding elset. I waited, but none has appeared (yet).
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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
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