Re: Decay watch: February 21

Alan Pickup (alan@wingar.demon.co.uk)
Mon, 22 Feb 1999 20:31:20 +0000

I wrote...
>---------------------------------------------------------------------
>Object: #25633 = 99- 7 B = Soyuz TM-29 Soyuz r
>...
>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: ...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).

The missing elset did materialise eventually...

Soyuz TM-29 Soyuz r                              137 x 128 km
1 25633U 99007B   99052.69943327  .29150271  12653-4  21260-3 0   164
2 25633  51.6433 215.6101 0007075 147.0522 213.1042 16.52503020   253

The drag term is much less than would be expected from earlier elsets
were it not for the apparent effect of the change in atmospheric flow
regime near the end. Taking just this elset, SatEvo predicts decay at 
18:20 UTC on February 21. Attempts to fit it with earlier elsets are not
convincing.

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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