RE: USA 129 Jan 30 2014

From: Ted Molczan <ssl3molcz_at_rogers.com>
Date: Sun, 2 Feb 2014 10:44:38 -0500
Greg Roberts wrote:

> 2nd pass:
> 
> USA 129 prediction: 21h03m47s UT az 228.0 el 22.4  --- nil seen
>          1st boost orbit  21h08m37s UT az 228    el 20     --- nil seen
>         2nd boost orbit  21h12m26s UT az 228    el 18.5
> 
>         I observed az 228.0 el 22.4 from 20h59m35s to 21h11m35s UT and saw
> nothing.
> 
>         So again not too conclusive - nothing seen in 1st boost orbit but did
> not wait long enough for boost orbit #2, but, as in first pass, boost orbit #2
> would have probably been outside the field of view as well.
> 
> Boost orbit #3 was a long way away from either so obviously not looked for or
> seen.
> 
> So, at the moment it looks like USA 129 not in original orbit, nor possibly in
> boost orbit no 1 -  so possibily still in boost orbit #2 or #3 not observed
> which I will do tonight if clear.

Thank you, Greg. Your 2nd pass is especially helpful in narrowing the re-boost time period. I am not surprised that the
70001 TLE can be excluded, because it almost certainly defines the extreme earliest boost time. I offer the appended
revised set of search TLEs that better bracket the likely range after allowing for your information.

Note that I have included boosts at apogee as well as perigee, since the predicted tracks can differ considerably,
especially if observing at high elevation. They will diverge more with passage of time from epoch.

Note also that there is some uncertainty in the pre-boost position, which results in some uncertainty in the search TLE
mean motion; therefore, I recommend beginning a search session 1 or 2 min. earlier than predicted by 71001.

Good luck, Greg.

Ted Molczan


Boost at 11:30:49 UTC perigee                            307 X 755 km
1 71001U          14027.77763757  .00015429  00000-0  24929-3 0    05
2 71001  97.5750  83.3491 0324389 181.9039 178.0984 15.10755478    02

Boost at 12:18:25 UTC apogee                             320 X 743 km
1 71002U          14027.77759560  .00013195  00000-0  24929-3 0    01
2 71002  97.5502  83.3481 0306044 181.9041 178.1052 15.10684931    00

Boost at 14:41:10 UTC perigee                            307 X 765 km
1 71003U 96072A   14027.77759665  .00015236  00000-0  24929-3 0    00
2 71003  97.6010  83.3488 0331523 181.9041 178.0954 15.09086608    08

Boost at 15:28:45 UTC apogee                             330 X 743 km
1 71004U          14027.77751953  .00011533  00000-0  24929-3 0    05
2 71004  97.5549  83.3480 0298105 181.9043 178.1078 15.08941379    09

Boost at 17:51:29 UTC perigee                            307 X 814 km
1 71005U          14027.77739930  .00014397  00000-0  24929-3 0    08
2 71005  97.7244  83.3468 0365735 181.9048 178.0810 15.01092252    02

Boost at 18:39:04 UTC apogee                             384 X 743 km
1 71006U          14027.77713777  .00006409  00000-0  24929-3 0    05
2 71006  97.5782  83.3478 0258494 181.9056 178.1209 15.00252234    01


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Received on Sun Feb 02 2014 - 15:45:50 UTC

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