IMHO, it seems that a small manoeuver by 161 is unusual, and probably done only to correct inclination or track timing in preparation for the next one by 129. OTOH it is more likely that when 161 is raised, it is by a large amount (to reach 14.72 or so), although it did not reach the normally significant MM=14.84 yet. But it may be that they prefer to change the orbit while it is most difficult for amateurs to discover. Tony has only occasional passes around 20 deg elev, usually just above 10 deg. I may spot it in the afternoon twilight, low in NW. 129 is usually raised alone when the pass time reaches 2h 45m before 161, to a MM lower than that of 161, by an amount that causes the drag to reduce the pass time difference to 2h 20m by the time their MMs are equal. Roughly, this means that its new MM differs from that of 161 by the same amount as before, but with opposite sign. In this case, it would mean a change from 14.8456 to 14.8113, since 161 had 14.8284. By coincidence, or more likely careful planning, this 2h 45m diff was reached on the same day that USA 161 had its perigee on the equator ! Since it has not been found on any of Ted's search elsets, I would propose that the large raise was made, probably on the evening of Dec.19, when USA 161 perigee was on the equator. You can make search elsets by just adding small +- increments to MM, eg 14.719 14.739 and 14.733 14.753 USA 129 +19 m/s 1 24680U 96072A 3353.75010000 .00027406 00000-0 28356-3 0 11 2 24680 97.7982 53.4604 0545501 117.4163 359.3733 14.72878899 207 USA 161 +14 m/s 1 26934U 01044A 03353.84324512 .00002200 00000-0 90000-4 0 28 2 26934 97.9250 105.5870 0354827 0.1152 0.0078 14.74316830 15 ----- Original Message ----- > > The last time USA 161 manoeuvred, its mean motion went from about 14.834 rev/d > to 14.82 rev/d. This time, its mean motion likely had not quite reached 14.83 ----------------------------------------------------------------- To unsubscribe from SeeSat-L, send a message with 'unsubscribe' in the SUBJECT to SeeSat-L-request@satobs.org List archived at http://www.satobs.org/seesat/seesatindex.html
This archive was generated by hypermail 2b29 : Fri Dec 26 2003 - 07:58:05 EST