Brad Young's observations of 2010 Nov 26, at 12:10 UTC, revealed OTV 1-1 running about 7 s late relative the elements I posted yesterday, probably the result of one or more orbit maintenance manoeuvres within the span of the recent observations. The following elements are based on Brad's observations, and the most recent of Greg Roberts observations, and the assumption that it was coasting in the interim. X-37B OTV 1-1 283 X 291 km 1 36514U 10015A 10330.49573769 .00024523 00000-0 55503-4 0 04 2 36514 39.9869 93.3339 0006175 352.7017 7.3719 15.96472018 09 Arc 20101124.79-1126.51 WRMS resid 0.059 totl 0.035 xtrk The mean motion and rate of decay remain a bit uncertain, but predictions should be accurate to within a few seconds per day since epoch. Non-Positional Observations Are Useful Too Observations, like the one Robert Holdsworth reported today, are also useful, because they can provide an early warning that a large manoeuvre has occurred, and help narrow down the time when it occurred. http://satobs.org/seesat/Nov-2010/0293.html The sooner we know that OTV 1-1 has "disappeared", or is running significantly early or late, the sooner we can organize a search to recover it, and determine its new orbit. The narrower the span between the last sighting in the last known orbit and the first evidence of a manoeuvre, the fewer the search planes we have to deal with. Bill Arnold's non-positional observation of OTV 1-1 on Nov 12 UTC, would not normally have been of much interest to me: http://satobs.org/seesat/Nov-2010/0159.html but it became very important two days later, when Ed Cannon, Brad Young and Mike McCants reported it a no-show: http://satobs.org/seesat/Nov-2010/0189.html Ted Molczan _______________________________________________ Seesat-l mailing list http://mailman.satobs.org/mailman/listinfo/seesat-l
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