NROL-61/USA 269/Centaur observed by Paul Camilleri

From: C. Bassa via Seesat-l <seesat-l_at_satobs.org>
Date: Fri, 29 Jul 2016 08:23:34 +0200
Hi all,

Paul Camilleri was able to observe the NROL-61 fuel dump from
Australia and track the payload and the Centaur upper stage between
13:47 and 15:54UT today. He obtained a set of images with an 85mm and
a 180mm lens and he kindly shared the images with me. I calibrated the
astrometry of the 85mm images and measured the positions listed below.

The Centaur was tracked longest and the arc is long enough to fully
constrain the orbit.

NROL-61 Centaur                                       -252 x 28014 km
1 75403U 16710A   16210.61864000  .00000000  00000-0  00000-0 0    02
2 75403  18.8996 323.3539 6976124 166.7514  81.1155  3.01131186    00
# 20160728.57-20160728.66, 34 measurements, 0.042 deg rms

The negative perigee is consistent with the planned deorbit and the
orbit intersects the area published in the NOTAM at the planned time.

The payload was faint and only visible on a few of the images. This
elset is based on Ted Molczan's pre-launch elset, keeping the
eccentricity and mean motion fixed but fitting for the other
parameters.

USA 269                                                843 x 35739 km
1 41724U 16047A   16210.54537038  .00000000  00000-0  00000-0 0    04
2 41724  18.8823 324.8886 7072816 178.2633 359.8822  2.24094669    09
# 20160728.59-20160728.64, 11 measurements, 0.041 deg rms

The orbit for the payload and the Centaur have closest approach
between 13:41 and 13:45UT, suggesting the deorbit burn occurred a few
minutes before Paul took his first image.

This orbit for the payload should be accurate enough to recover it
during the next few days, provided it does not maneuver in between.

It is interesting to note that at 18.9 deg, the inclination is about
1.8 deg smaller than the initial GTO orbit of USA 252/NROL-33, the
previous SDS that was launched towards a geosynchronous
orbit. However, it is significantly larger than the 13.4 deg
inclination that was suggested by the orientation of the Centaur
deorbit area, suggesting the payload is heavier than estimated before
launch.

Regards,
   Cees Bassa

41724 16 047A   8600 G 20160728141028013 27 25 1701830-073245 17 S
41724 16 047A   8600 G 20160728141214026 27 25 1707396-073076 17 S
41724 16 047A   8600 G 20160728142029011 27 25 1730753-071778 17 S
41724 16 047A   8600 G 20160728142859030 27 25 1751085-065735 17 S
41724 16 047A   8600 G 20160728143228982 27 25 1758501-064839 17 S
41724 16 047A   8600 G 20160728144229030 27 25 1817458-061855 17 S
41724 16 047A   8600 G 20160728144729011 27 25 1825827-060304 17 S
41724 16 047A   8600 G 20160728145028982 27 25 1830645-055419 17 S
41724 16 047A   8600 G 20160728145359021 27 25 1835962-054310 17 S
41724 16 047A   8600 G 20160728150158973 27 25 1847123-051701 17 S
41724 16 047A   8600 G 20160728151659002 27 25 1905277-042951 17 S

75403 16 710A   8600 G 20160728134742029 27 25 1519652-062884 17 S
75403 16 710A   8600 G 20160728134906960 27 25 1527093-064062 17 S
75403 16 710A   8600 G 20160728135435021 27 25 1553332-071407 17 S
75403 16 710A   8600 G 20160728135559002 27 25 1559408-071999 17 S
75403 16 710A   8600 G 20160728135943987 27 25 1614547-073143 17 S
75403 16 710A   8600 G 20160728140042998 27 25 1618298-073353 17 S
75403 16 710A   8600 G 20160728140250006 27 25 1626091-073714 17 S
75403 16 710A   8600 G 20160728140728992 27 25 1641744-073980 17 S
75403 16 710A   8600 G 20160728140843987 27 25 1645670-074038 17 S
75403 16 710A   8600 G 20160728141028013 27 25 1650920-073990 17 S
75403 16 710A   8600 G 20160728141214026 27 25 1656091-073856 17 S
75403 16 710A   8600 G 20160728141500000 27 25 1703713-073599 17 S
75403 16 710A   8600 G 20160728142029011 27 25 1717740-072729 17 S
75403 16 710A   8600 G 20160728142614006 27 25 1730860-071582 17 S
75403 16 710A   8600 G 20160728142859030 27 25 1736664-070932 17 S
75403 16 710A   8600 G 20160728143228982 27 25 1743667-070050 17 S
75403 16 710A   8600 G 20160728143529040 27 25 1750314-065119 17 S
75403 16 710A   8600 G 20160728143959040 27 25 1757386-064006 17 S
75403 16 710A   8600 G 20160728144229030 27 25 1801619-063259 17 S
75403 16 710A   8600 G 20160728144459021 27 25 1805646-062515 17 S
75403 16 710A   8600 G 20160728144729011 27 25 1809640-061742 17 S
75403 16 710A   8600 G 20160728145028982 27 25 1814219-060801 17 S
75403 16 710A   8600 G 20160728145359021 27 25 1819307-055682 17 S
75403 16 710A   8600 G 20160728145714026 27 25 1823853-054644 17 S
75403 16 710A   8600 G 20160728150158973 27 25 1830171-053084 17 S
75403 16 710A   8600 G 20160728150959011 27 25 1840138-050417 17 S
75403 16 710A   8600 G 20160728151359030 27 25 1844825-045058 17 S
75403 16 710A   8600 G 20160728151659002 27 25 1848227-044051 17 S
75403 16 710A   8600 G 20160728152559002 27 25 1857860-040984 17 S
75403 16 710A   8600 G 20160728153058982 27 25 1902916-035263 17 S
75403 16 710A   8600 G 20160728153758973 27 25 1909706-032809 17 S
75403 16 710A   8600 G 20160728154559011 27 25 1917037-030049 17 S
75403 16 710A   8600 G 20160728154759021 27 25 1918828-025337 17 S
75403 16 710A   8600 G 20160728155358963 27 25 1924038-023234 17 S
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Received on Fri Jul 29 2016 - 01:24:20 UTC

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