USA 259 elements from observations

From: Ted Molczan via Seesat-l <seesat-l_at_satobs.org>
Date: Wed, 7 Jan 2015 08:24:24 -0500
Peter Wakelin observed 14081A / 40344 on 2015 Jan 06 UTC, more than 13 min. late relative the 15004.75625000 TLE,
revealing that it had made one or more manoeuvres.

Based on Peter's observations and a manoeuvre at the perigee of Jan 4 near 19:03:30 UTC, this would be the approximate
orbit:

                                                      2116 X 38167 km
1 70001U          15006.75694444  .00000000  00000-0  00000-0 0    06
2 70001  62.8366 210.1344 6797057 266.9758 340.4345  2.01014355    04

Assuming a manoeuvre at the perigee of Jan 5 near 06:56:26 UTC, this would be the approximate orbit:

                                                      2116 X 38223 km
1 70002U          15006.75694444  .00000000  00000-0  00000-0 0    07
2 70002  62.8366 210.1344 6800441 266.9758 340.4734  2.00695941    04

I evaluated the apogee passage that occurred between the above times, and ruled it out based on cross-track residuals.

The manoeuvre need not have occurred exactly at perigee, in which case it may run significantly early or late tonight
relative either TLE. Mike McCants pointed out that it could very well have achieved ~2.006 rev/d.

I noticed a significant increase in the brightness data Peter reported, Jan 6 being the brightest yet. The attachments
compare 14081A against both known Trumpet generations. 

http://satobs.org/seesat_ref/misc/Trumpet_Gen_1_and_14081A.pdf

http://satobs.org/seesat_ref/misc/Trumpet_FO_and_14081A_v2.pdf

The difference in brightness between the two Trumpet generations is about half a magnitude. 14081A could match either
generation, but it looks right at home with Trumpet Gen 1. 14081A's higher initial perigee explains at least some of the
reason for using a more powerful rocket than for Trumpet FO. Perhaps the payload is also larger and heavier. Further
brightness obs may eventually help settle the question.

Ted Molczan


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Received on Wed Jan 07 2015 - 07:24:52 UTC

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