Updated elements

From: Ted Molczan (ssl3molcz@rogers.com)
Date: Sat Oct 06 2012 - 16:04:00 UTC

  • Next message: C. Bassa: "CB Obs October 6/7, 2012; Part 1"

    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
    
    
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