Re-entry alerts for N. America tonight

From: Ted Molczan via Seesat-l <seesat-l_at_satobs.org>
Date: Fri, 24 Jul 2015 21:26:28 -0400
A couple of large objects are nearing decay tonight, expected to occur in the early hours (UTC) of July 25, and there is
a definite slim chance of visibility from North America.

1. 83111B / 14484

USSTRATCOM's latest TIP message for 83111B / 14484 puts decay at 04:42 UTC, over 58.3 N, 79.8 W. Over the previous half
hour or so, it will be on an ascending track that crosses N.W South America, Central America, the Caribbean, and Eastern
N. America. The prediction time uncertainty is 2 hours, so for practical purposes, we don't know when and where it will
descend. My Satana analyses suggest that it may be down before 03:00 UTC, but it is impossible to be certain.

On the chance it decays near me, I intend to watch for it on my one pass, on 2015 Jul 25 near 04:21 UTC (the one over
Eastern N. America). Below is the approximate ground track in my region:

http://www.heavens-above.com/gtrack.aspx?satid=14484&mjd=57228.1811931965&lat=43.68764&lng=-79.39243&loc=Unspecified&alt
=0&tz=UCT

If it happens to be re-entering, then this estimated TLE will yield realistic predictions:

1 14484U 83111B   15206.18125000  .00000000  00000-0  00000-0 0    09
2 14484  82.7916 283.7685 0008063 244.1701 164.5200 16.74000000    07


2. 15035B / 40745

USSTRATCOM's latest TIP message for 15035B / 40745 puts decay at 06:08 UTC, over 6.6 S, 146.5 W. That is on an ascending
track that crosses parts of the U.S.A and Canada ~15 min. later. The prediction time uncertainty is 3 hours, so for
practical purposes, we don't know when and where it will descend. My Satana analyses suggest that it may be down before
04:00 UTC, but it is impossible to be certain.

On the chance it decays near me, I intend to watch for it on my two passes.

2.1 Pass of 2015 Jul 25 04:54 UTC:

Ground track in my region:

http://www.heavens-above.com/gtrack.aspx?satid=40745&mjd=57228.2046459998&lat=43.68764&lng=-79.39243&loc=Unspecified&alt
=0&tz=UCT

If it happens to be re-entering, then this estimated TLE will yield realistic predictions:

1 40745U 15035B   15206.20416667  .00000000  00000-0  00000-0 0    03
2 40745  51.6274 252.8546 0001266  46.7137  12.1548 16.73000000    00

2.2 Pass of 2015 Jul 25 06:25 UTC:

Ground track in my region:

http://www.heavens-above.com/gtrack.aspx?satid=40745&mjd=57228.2677590336&lat=43.68764&lng=-79.39243&loc=Unspecified&alt
=0&tz=UCT

If it happens to be re-entering, then this estimated TLE will yield realistic predictions:

1 40745U 15035B   15206.26736111  .00000000  00000-0  00000-0 0    08
2 40745  51.6274 252.4961 0001269  46.9812  25.7986 16.73000000    08

It is highly unlikely that a re-entry will occur on any of the above passes. Certainly, there is no guarantee. But if it
does happen, and I am not watching, then I am guaranteed to miss it.

Ted Molczan


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Received on Fri Jul 24 2015 - 20:27:06 UTC

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