Re: Decay update: October 14
Alan Pickup (alan@wingar.demon.co.uk)
Wed, 15 Oct 1997 19:47:48 +0100
In message <3444D9D5.C4057675@tt-tech.se>, Bjoern Gimle <bjorn@tt-
tech.se> writes
>Last (latest??) elset on OIG at 13:22 UT was
>
>Element set number = 1
>1 24908U 97043F 97288.47305831 .10144961 -14033-5 36726-3 0 1634
>2 24908 82.6031 342.0620 0023045 137.1462 223.8436 16.41579739 8761
>
>ndot2 and MM look too small compared to Alan's evolution, but on the
>other hand I don't get his results when using his 287.55 elset !
>With elset 163, my SatEvo gives the following :
>
> ... <snipped>
The latest elset from OIG is:
Iridm Delta r 5.9 2.4 0.0 5.6 d 163 x 140 km
1 24908U 97043F 97288.59470742 .16560798 -13707-5 33729-3 0 1667
2 24908 82.6011 341.9138 0017654 147.5192 212.7249 16.45490302 8788
confirming that it outlasted the SatEvo evolution I posted yesterday.
In fact, Bjoern, that was not generated from the raw OIG elset at
97287.55 - I had extrapolated that OIG elset to a (SatEvo) equator
crossing and replaced its ndot2 and MM terms by values computed by
forcing a SatEvo evolution through the elsets at 97286.56, 97287.12 and
97287.55. You can obtain that evolution by running SatEvo with the seed
elset:
Iridm Delta r 5.9 2.4 0.0 5.6 d 253 x 173 km
1 24908U 97043F 97286.56966449 .02890138 29514-2 79709-3 0 91506
2 24908 82.6147 344.2486 0061228 148.6185 211.7483 16.22414377 8454
Unfortunately, the Delta was not paying attention and was already
running 8 seconds late by the epoch of the OIG elset at 97287.92.
If my new analysis is better, it may have decayed at about October 15.68
(16:20 UTC) or it may have survived another 30-60 minutes. My new
evolution through the equator crossings of the latest elsets runs:
Iridm Delta r 5.9 2.4 0.0 5.6 d 177 x 147 km
1 24908U 97043F 97288.47292115 .14402651 16622+0 53133-3 0 91630
2 24908 82.6031 342.0622 0023050 137.1468 223.0331 16.41483927 8764
Iridm Delta r 5.9 2.4 0.0 5.6 d 170 x 144 km
1 24908U 97043F 97288.53384559 .18218212 28377+0 50676-3 0 91632
2 24908 82.6024 341.9906 0019817 136.8916 223.2637 16.43451072 8779
Iridm Delta r 5.9 2.4 0.0 5.6 d 160 x 139 km
1 24908U 97043F 97288.59468583 .25526369 62365+0 48995-3 0 91637
2 24908 82.6015 341.9188 0015946 136.6360 223.4895 16.46055398 8784
Iridm Delta r 5.9 2.4 0.0 5.6 d 146 x 132 km
1 24908U 97043F 97288.65540542 .47234700 26470+1 51147-3 0 91630
2 24908 82.6002 341.8468 0010771 136.3797 223.7054 16.50165659 8790
OIG may yet issue an elset near this final epoch.
Alan
--
Alan Pickup | COSPAR site 2707: 55d53m48.7s N 3d11m51.2s W 156m asl
Edinburgh | Home: alan@wingar.demon.co.uk +44 (0)131 477 9144
Scotland | SatEvo satellite page: http://www.wingar.demon.co.uk/satevo/