NOSS 3-4 elements

From: Ted Molczan (ssl2molcz@rogers.com)
Date: Fri Jul 27 2007 - 10:40:19 EDT

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    Russell Eberst's observations of 2007 Jul 27 UTC revealed that 07027A and C have
    raised their orbits again. Both were about 10 s late relative their epoch
    07207.286 orbits.
    
    Recent manoeuvres have increased the orbital period between 3.6 and 4.2 s,
    averaging near 3.8 s. Here are their approximate new orbits, assuming a 3.8 s
    increase in period:
    
    NOSS 3-4 (A)     0.0  0.0  0.0  4.9 v
    1 70001U          07208.02129679  .00000018  00000-0  20000-4 0    09
    2 70001  63.3500 296.1195 0212300 149.6510 211.7019 13.60976000    07
    
    NOSS 3-4 (C)     0.0  0.0  0.0  4.9 v
    1 70002U          07208.02314820  .00000017  00000-0  20000-4 0    03
    2 70002  63.3618 296.1414 0200300 150.3181 210.9399 13.61002000    05
    
    Prediction time uncertainty will be about 5 s per 24 h since epoch.
    
    Observations of 07027B by Daniel, Lucille and Russell, result in the following
    improved elements:
    
    NOSS 3-4 r       0.0  0.0  0.0  5.0 v
    1 31702U 07027B   07208.17709442  .00000023  00000-0  10000-4 0    03
    2 31702  63.2474 285.2552 0145701 194.1648 165.5309 14.17698600    02
    Arc 2007 Jul 24.23 - 27.19, WRMS residuals = 0.034 deg
    
    1 31702U 07027B   07208.17710651 -.00000272  00000-0 -12072-3 0    05
    2 31702  63.2835 285.2888 0140762 194.9531 164.7350 14.17700966    02
    Arc 2007 Jun 15.73 - 27.19, WRMS residuals = 0.069	 deg
    
    The longer arc demonstrates the close agreement between the recent observations
    and the data extracted from Babak A. Tafreshi's images of the propellant
    blow-down. I would not expect exact agreement, mainly because of:
    
    - approx 1 s uncertainty in times of the Tafreshi images
    
    - apparent effects of subsequent out-gassing on the orbit
    
    - perturbing effects of the Earth's odd zonal harmonics on eccentricity of
    orbits near 63.4 deg inclination
    
    Ted Molczan
    
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