Re: Mir Debris 23689 Obs

Alan Pickup (alan@wingar.demon.co.uk)
Sun, 13 Oct 1996 15:13:54 +0100

In message <199610121922.VAA25076@ratatosk.algonet.se>, Bjoern Gimle
<b_gimle@algonet.se> writes
>Re: Steve Bolton's (sbolton@nbnet.nb.ca) obs report :
>
>My post-mortem analysis gives decay at Oct.11 23:00 UT
>
>>Satspy using Allan Pickup's elsets predicted a pass of 23689 at 0146 UT on
>>Oct 12. Pass was in shadow so ideal if object reentering. Saw nothing but
>>lots of stars, a fine night for astronomy.

A rather large difference of opinion/analysis here. OIG elsets for this
object were rather sparce, but the two final ones were:

Mir debris JL                                    210 x 203
1 23689U 86017JL  96283.85011482  .02762804  11967-4  93099-3 0  3834
2 23689  51.6191 232.4108 0005063 163.6868 199.2937 16.24875924608366
Mir debris JL                                    176 x 160
1 23689U 86017JL  96284.76872468  .10459325  00000-0  82005-3 0  3842
2 23689  51.6191 227.2543 0012104 201.5828 158.5386 16.39043505608558

Note that day 94284 is October 10. When I fit a SatEvo evolution through
three of the equator crossings indicated by the final four elsets, I
compute rather different values for the ndot/2 term for these two
elsets: 0.0415 and 0.1607 respectively (with corresponding n values of
16.2561 and 16.3907). That evolution, which satisfies the equator
crossing of the 4th elset (for 96282.98) to better than 4 seconds, leads
to a decay at October 11.0.

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