Russell Eberst, Björn Gimle, Marco Langbroek, Pierre Neirinck, and Scott Tilley contributed observations used to produce the following elements: USA 161 263 X 784 km 1 26934U 01044A 11255.30275232 .00025734 00000-0 21628-3 0 07 2 26934 97.8222 9.1129 0377498 193.9089 165.1517 15.13281946 01 Arc 201109011-0912.32 WRMS resid 0.021 totl 0.012 xtrk The arc probably is longer than ideal, given the recent spike in geomagnetic activity, but the results appear to be reasonably accurate, though perhaps not quite as precise as implied by the residuals. Yesterday, I finally hit on the correct solution to the observations of Aug 31, Sep 01, Sep 03 and Sep 06: the object had manoeuvred to a lower, not a higher orbit. Among the many problems with the higher orbit, was that the plane was ~1.3 deg farther east than could be explained by the apparently coplanar manoeuvre(s). The greater eastward rate of precession of a lower orbit, of mean motion ~15.15 rev/d, readily accounted for the planar shift, and quickly led to a preliminary ~15.13 rev/d solution that fit nearly all of the observations. Scott made the confirming observations last night. It appears that a single manoeuvre was made on Aug 24, near 12-13 h UTC, which decreased the perigee about 40 km, the apogee about 120 km, and the argument of perigee about 14 deg. The ground track of the previous orbit repeated after 7 days (104 revs), the present one after 8 days (121 revs). All of my earlier estimates of the post-manoeuvre orbit should be discarded. Ted Molczan _______________________________________________ Seesat-l mailing list http://mailman.satobs.org/mailman/listinfo/seesat-l
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