Cees Bassa, Derek Breit, Russell Eberst, Alberto Rango, Greg Roberts, Scott Tilley and Brad Young contributed observations used to update one or more of the following element sets. Recent observations of ORS 1 by Alberto, Brad and Derek confirm the reliability of my zero-drag, mean mean-motion TLE, intended to account for the object's frequent anti-drag manoeuvres. Over the period 2012 Aug 07 - Oct 05 UTC, prediction time error is +/- 32 s, and cross-track error typically is well under 0.1 deg. This TLE, or one similar in concept, is especially useful to recover the object after a spell of invisibility, provided that it continues to maintain the same mean altitude. ORS 1 417 X 419 km 1 37728U 11029A 12268.03595803 .00000000 00000-0 00000-0 0 05 2 37728 40.0000 241.8967 0002000 87.7354 272.3686 15.50388770 04 Russell's observations of Oct 06 UTC reveal that 12048P led 12048A by nearly 9 s, and that it had manoeuvred lower since it was last observed, two days earlier. The mean motion of my 12048P TLE is based on my guess that it has matched that of 12048A. NOSS 3-6 (A) 1012 X 1198 km 1 38758U 12048A 12280.17540493 .00000000 00000-0 00000-0 0 05 2 38758 63.4381 345.0979 0124580 179.3812 180.7389 13.40854471 09 Arc 20121001.12-1006.2 WRMS resid 0.023 totl 0.012 xtrk NOSS 3-6 (P) 1012 X 1198 km 1 38773U 12048P 12280.17530152 .00000000 00000-0 00000-0 0 03 2 38773 63.4392 344.9175 0124620 178.3688 181.7768 13.40854000 09 Arc 20121006.2-01006.2 WRMS resid 0.004 totl 0.004 xtrk I expect the pair to maintain approximately the present spacing for the remainder of the their operational life. We should wait a day or two to confirm, then we may decide to swap designations, in accordance with our (not always followed) convention to assign "A" to the leader. Their present mean motion is a bit greater than that of the present NOSS constellation standard, 13.4061 rev/d. I believe that is intended to enable them to gradually drift to a relative time of ascending node passage that optimizes the coverage of the entire constellation. Previous NOSS 3 spacecraft have spent several months in drift mode before manoeuvring to synchronize with the constellation. Additional information about NOSS: http://www.satobs.org/noss.html Ted Molczan _______________________________________________ Seesat-l mailing list http://mailman.satobs.org/mailman/listinfo/seesat-l
This archive was generated by hypermail 2b29 : Sat Oct 06 2012 - 16:05:04 UTC