Description of 2-line elements: http://www.satobs.org/element.html NOSS 3-3 (A) 0.0 0.0 0.0 4.0 v 1 28537U 05004A 05063.04932079 .00000011 00000-0 20000-4 0 03 2 28537 63.4381 89.2141 0131311 179.8948 180.2126 13.39750730 01 Arc 2005 Mar 03.83 - 04.06, WRMS residuals = 0.015 deg NOSS 3-3 (C) 0.0 0.0 0.0 4.0 v 1 28541U 05004C 05063.12407209 .00000011 00000-0 20000-4 0 09 2 28541 63.4375 89.1988 0127291 179.7350 180.3764 13.39772996 02 Arc 2005 Mar 02.79 - 04.13, WRMS residuals = 0.021 deg NOSS 3-3 r 0.0 0.0 0.0 4.7 v 1 28538U 05004B 05062.16808284 .00003528 00000-0 58538-2 0 07 2 28538 63.8274 92.5368 0137786 176.4636 183.7401 13.42817866 06 Arc 2005 Feb 19.20 - Mar 03.19, WRMS residuals = 0.025 deg My observation of the Centaur on Mar 04 UTC appears to be significantly late, so I ended the arc at the ascending node prior to Alberto Rango's observation of Mar 03 UTC. I suspected that my timing would prove late, since my observation nearly coincided with a minimum, making it too faint to see easily. It knew it was a bad sign when I saw it de-cloak well past my reference stars as I hit the stopwatch. As of the epoch of 05004C, above, it trailed 05004A by 9.54 s at the ascending node, closing at the rate of 0.11 s per rev. At that rate, they would reach their operational separation of 8 s, on Mar 05, near 04:00 UTC, at which point one of them may manoeuvre to match the mean motion of the other, fixing the separation. Ultimately, they will manoeuvre to match the mean motion of the other 5 operational groups. Here is recent data from one member of each group: NOSS SSN Desig Epoch Mean Motion 2-1 20691 90050C 05058.20098807 13.40465449 2-2 21799 91076C 05059.20017328 13.40464771 2-3 23908 96029C 05058.79293750 13.40463693 3-1 26907 01040C 05058.77487687 13.40468501 3-2 28095 03054A 05059.18383316 13.40466464 The range of orbital period of the above spans just 0.023 s. The number, magnitude and timing of the additional manoeuvres by which 05004A and C will match the above is known only to their operators. Based on the observed behaviour of the NOSS 3-1 and 3-2 groups, I expect one or more additional manoeuvres over the next week or two, resulting in a temporary mean motion within approx +/- 0.0015 rev/d of the above groups. They would remain at the temporary mean motion for several months, then manoeuvre to match the above groups. Ted Molczan ------------------------------------------------------------------------- Subscribe/Unsubscribe info, Frequently Asked Questions, SeeSat-L archive: http://www.satobs.org/seesat/seesatindex.html
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