RE: Total confusion about SZ-4 elsets?

From: Ted Molczan (molczan@rogers.com)
Date: Tue Dec 31 2002 - 10:04:40 EST

  • Next message: Harro Zimmer: "MOLNIYA 1-61 decayed"

    Alan Pickup wrote:
    
    > This leaves just four orphan elsets, the earlier ones issued 
    > under the B 
    > designation:
    > 
    > 1 27631U 02061B   02363.99063452 -.00002648  83756-5  00000-0 0    19
    > 2 27631  42.4166 338.1817 0096007 122.0244 238.9998 16.07463202    45
    > 
    > 1 27631U 02061B   02364.29795330  .08819089  86747-5  32762-3 0    63
    > 2 27631  42.4377 336.1153 0023606 141.5036 214.4799 16.41507587    96
    > 
    > 1 27631U 02061B   02364.29867553  .99999999  86250-5  14303-1 0    78
    > 2 27631  42.3982 336.1522 0029614 151.2781 209.0607 16.36663733    95
    > 
    > 1 27631U 02061B   02364.32335142 -.00002781  87973-5  00000-0 0    29
    > 2 27631  42.4166 336.0438 0096007 124.5196  22.9059 16.29358713    92
    > 
    > The first of these is not dissimilar to that of the rocket at 
    > the time but appears to be 58 seconds ahead of the rocket. Was there 
    > ever a third object?
    
    I suspect that the first of the above was the payload, and that the 
    one assigned to the payload was the rocket:
    
    1 27630U 02061A   02363.99130504 -.00002620  82868-5 -20368-5 0    19
    2 27630  42.4085 338.1747 0100490 131.4080 229.5479 16.03477566    55
    
    Except for the spurious decay terms, this set agrees very closely with 
    this later elset of the rocket:
    
    1 27630U 02061A   02364.38854632  .00779380  82659-5  57683-3 0    50
    2 27630  42.4073 335.6309 0099754 134.9968   2.7393 16.04294545   119
    
    Another possibility is that the elsets were correctly assigned, and that
    the one for the rocket was simply less accurate than that of the payload.
    
    I suspect that the three rocket elsets above, with the high mean motion,
    were the result of a mishap in the tracking and/or analysis.
    
    Notice that the last of the above has the same inclination and eccentricity
    and nearly the same decay term as the first. My guess is that the erroneous
    mean motion had been detected and the analysis re-started using the first
    elset as the starting point. The strategy is to hold constant those elements
    that are the most reliable and the least likely to have changed very much.
    This should help reveal the bad data, which should have much greater residuals
    than the good data.
    
    How could this have happened? Perhaps an unrelated object passed near 
    the predicted track of the real one. Perhaps the best analysts had been 
    assigned to track Santa. who having accomplished their mission went on 
    vacation, leaving the place in the charge of second-stringers.
    
    Ted Molczan
    
    
    -----------------------------------------------------------------
    Unsubscribe from SeeSat-L by sending a message with 'unsubscribe'
    in the SUBJECT to SeeSat-L-request@lists.satellite.eu.org
    http://www.satellite.eu.org/seesat/seesatindex.html
    



    This archive was generated by hypermail 2b29 : Tue Dec 31 2002 - 23:27:27 EST