RE: Lacrosse 5 and USA 129 elements

From: Ted Molczan (molczan@rogers.com)
Date: Tue May 10 2005 - 12:41:57 EDT

  • Next message: Leo Barhorst: "Re: Re: LB obs 2005 May 5 morning"

    Since I posted my epoch 05129.10360012 elset of 96072A, additional observations
    became available, so I have analyzed the larger data set, and replaced the
    earlier elset with this one:
    
    USA 129         15.0  3.0  0.0  5.3 v
    1 24680U 96072A   05129.10360041  .00009106  00000-0  12435-3 0    03
    2 24680  97.9728 192.9242 0525480 285.6540  68.7299 14.73013634    00
    Arc 2005 May 05.92 - 09.11, WRMS residuals = 0.020 deg
    
    Last night, the object was running nearly 0.7 s early relative the above,
    indicating a significant increase in rate of decay, perhaps related to the
    geomagnetic storm of May 08 UTC. I produced this reduced-arc elset, by
    propagating the above elset to the ascending node prior to the latest
    observations, and adjusting only B* (the decay term), mean anomaly and mean
    motion:
    
    USA 129         15.0  3.0  0.0  5.3 v
    1 24680U 96072A   05130.12250838  .00012092  00000-0  16499-3 0    01
    2 24680  97.9728 193.9300 0525400 282.3745  71.9156 14.73045721    09
    Arc 2005 May 08.84 - 10.13, WRMS residuals = 0.016 deg
    
    As for Lacrosse 5, I am reasonably certain that this was its orbit until late on
    May 08 UTC:
    
    1 28646U 05016A   05128.93811057  .00000042  00000-0  10000-4 0    02
    2 28646  57.0097  98.9510 0004211 173.0227 187.0846 14.53350785    03
    Arc 2005 May 05.10 - 08.96, WRMS residuals = 0.030 deg
    
    There appears to have been a subsequent small manoeuvre, perhaps a nudge closer
    to the eccentricity and argument perigee of the typical 57 deg Lacrosse frozen
    orbit. Here are preliminary elements, based on a fairly short arc:
    
    Lacrosse 5       0.0  0.0  0.0  3.4 v
    1 28646U 05016A   05130.03868548  .00000042  00000-0  10000-4 0    03
    2 28646  57.0063  94.8667 0001657  79.1016 281.0183 14.53353903    01
    Arc 2005 May 09.09 - 10.20, WRMS residuals = 0.021 deg
    
    Ted Molczan
    
    
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