NOSS 3-3 elements

From: Ted Molczan (molczan@rogers.com)
Date: Fri Mar 04 2005 - 11:25:21 EST

  • Next message: Greg Roberts: "Update obs 01 March 2005"

    Description of 2-line elements: http://www.satobs.org/element.html
    
    NOSS 3-3 (A)     0.0  0.0  0.0  4.0 v
    1 28537U 05004A   05063.04932079  .00000011  00000-0  20000-4 0    03
    2 28537  63.4381  89.2141 0131311 179.8948 180.2126 13.39750730    01
    Arc 2005 Mar 03.83 - 04.06, WRMS residuals = 0.015 deg
    
    NOSS 3-3 (C)     0.0  0.0  0.0  4.0 v
    1 28541U 05004C   05063.12407209  .00000011  00000-0  20000-4 0    09
    2 28541  63.4375  89.1988 0127291 179.7350 180.3764 13.39772996    02
    Arc 2005 Mar 02.79 - 04.13, WRMS residuals = 0.021 deg
    
    NOSS 3-3 r       0.0  0.0  0.0  4.7 v
    1 28538U 05004B   05062.16808284  .00003528  00000-0  58538-2 0    07
    2 28538  63.8274  92.5368 0137786 176.4636 183.7401 13.42817866    06	
    Arc 2005 Feb 19.20 - Mar 03.19, WRMS residuals = 0.025 deg
    
    My observation of the Centaur on Mar 04 UTC appears to be significantly late, so
    I ended the arc at the ascending node prior to Alberto Rango's observation of
    Mar 03 UTC. I suspected that my timing would prove late, since my observation
    nearly coincided with a minimum, making it too faint to see easily. It knew it
    was a bad sign when I saw it de-cloak well past my reference stars as I hit the
    stopwatch.
    
    As of the epoch of 05004C, above, it trailed 05004A by 9.54 s at the ascending
    node, closing at the rate of 0.11 s per rev. At that rate, they would reach
    their operational separation of 8 s, on Mar 05, near 04:00 UTC, at which point
    one of them may manoeuvre to match the mean motion of the other, fixing the
    separation.
    
    Ultimately, they will manoeuvre to match the mean motion of the other 5
    operational groups. Here is recent data from one member of each group:
    
    NOSS   SSN   Desig        Epoch      Mean Motion
    2-1   20691  90050C  05058.20098807  13.40465449
    2-2   21799  91076C  05059.20017328  13.40464771
    2-3   23908  96029C  05058.79293750  13.40463693
    3-1   26907  01040C  05058.77487687  13.40468501
    3-2   28095  03054A  05059.18383316  13.40466464
    
    The range of orbital period of the above spans just 0.023 s.
    
    The number, magnitude and timing of the additional manoeuvres by which 05004A
    and C will match the above is known only to their operators. Based on the
    observed behaviour of the NOSS 3-1 and 3-2 groups, I expect one or more
    additional manoeuvres over the next week or two, resulting in a temporary mean
    motion within approx +/- 0.0015 rev/d of the above groups. They would remain at
    the temporary mean motion for several months, then manoeuvre to match the above
    groups.
    
    Ted Molczan
    
    
    
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