Re: Decay of Progress M-36 Soyuz r (#25003)

Alan Pickup (alan@wingar.demon.co.uk)
Wed, 8 Oct 1997 17:36:16 +0100

Ignoring elsets which were superceded, the final ones for this object 
were:
Prog M-36 Soyuz r                                173 x 160 km
1 25003U 97058B   97280.33869518  .08017942  12444-4  59564-3 0   160
2 25003  51.6450 242.0512 0009759  69.8311 290.3778 16.39623097   278
Prog M-36 Soyuz r                                168 x 153 km
1 25003U 97058B   97280.46052074  .09108808  00000-0  45385-3 0   176
2 25003  51.6303 241.3696 0011424  65.9293 294.3629 16.41900924   299
Prog M-36 Soyuz r                                163 x 154 km
1 25003U 97058B   97280.50178241  .09334978  12502-4  44733-3 0   175
2 25003  51.6388 241.1380 0006553  75.5344 168.9508 16.42743204   290
Prog M-36 Soyuz r                                155 x 146 km
1 25003U 97058B   97280.67608796  .08968674  12597-4  21592-3 0   184
2 25003  51.6465 240.1385 0006567  70.3872 126.5633 16.45796307   322

which are respectively 0.07s late, 0.22s late, 0.91s early and 
(about) 21s late as compared with the SatEvo-predicted evolution I 
posted on the preceding day. The drag and mean motion terms in the last 
elset appear anomalously low and, since the epoch is far from the 
northbound equator crossing, these have a marked adverse effect on the 
final residual which compares the implied crossing times indicated by 
SatEvo and the OIG elset. Given the remarkably good fit of my 
prediction over the final day, I suspect that decay occurred at about 
October 7.74 (17:50 UTC), when it would have been ESE-bound
over the Pacific near 42 deg S and 180 deg E/W. However, this must be
uncertain by at least one hour.

Alan
-- 
 Alan Pickup | COSPAR site 2707:   55d53m48.7s N   3d11m51.2s W    156m asl
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