Updated elements

From: Ted Molczan (ssl3molcz@rogers.com)
Date: Tue Jul 17 2012 - 16:36:29 UTC

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    1. USA 236 observed; initial orbit
    
    Greg Roberts observed an UNID last night that I believe is USA 236 (12033A / 38466), the payload of NROL-38, launched on
    2012 Jun 20 UTC. The RAAN of the orbital plane is close to the pre-launch estimate of 274.1 deg; the initial inclination
    is the same as that of the previous SDS (USA 227 / 11011A / 37377), launched last year.
    
    USA 236
    1 70000U          12198.03083459  .00000000  00000-0  00000-0 0    03
    2 70000   4.9106 274.6677 0002000  86.7978 273.5037  1.00273700    02
    
    The eccentricity and mean motion are guesses; the remaining elements were allowed to vary in the analysis. The observed
    arc is too short to determine the mean motion with precision; I guessed that the object is synchronous, but it could
    still be drifting a bit.
    
    Its location near 30 W is a surprise. I guessed that it would reach GEO and be checked out within 20 deg of the
    operational SDS slot at 144 W, before taking over that slot from SDS 3-2 (01046A / 26948). I based this on the behavior
    of USA 227, which was checked out at 30 W for about 90 days before moving to the operational slot at 10 W. Apparently,
    30 W is the preferred location for SDS checkout. I still expect USA 236 to eventually move to 144 W.
    
    2. USA 237 observed; updated orbit
    
    Greg also made our second set of observations of USA 237, the payload of NROL-15, launched on 2012 Jun 29 UTC.
    
    USA 237                                              35677 X 36102 km
    1 38528U 12034A   12197.78746808  .00000000  00000-0  00000-0 0    07
    2 38528   3.5184 299.5137 0050303 310.7722  48.7936  0.99909995    04
    Arc 20120713.71-0716.76 WRMS resid 0.001 totl 0.000 xtrk
    
    It was near 82 E, drifting west 1.3 deg/d.
    
    3. Elisa West Satellites Found
    
    Alberto Rango and Scott Tilley have reported observations that confirm that the Elisa West plane is about 2.5 deg in
    RAAN west of the Elisa East Plane. Alberto observed 11076A; Scott observed A and C. Here are approximate elements that
    fit their observations:
    
    Elisa W11                                                673 X 688 km
    1 38007U 11076A   12199.27377032  .00000257  00000-0  50000-4 0    02
    2 38007  98.1589 272.9104 0010685 143.9017 216.2908 14.63069705    09
    
    Elisa W23                                                679 X 681 km
    1 38009U 11076C   12199.27393649  .00000256  00000-0  50000-4 0    05
    2 38009  98.1819 272.9488 0001486 102.4077 257.7291 14.63066078    02
    
    RAAN separation from the eastern plane is about 2.59 deg.
    
    Additional observations of all four satellites over several weeks would reveal the actual rate of decay, and perhaps
    their frequency of station-keeping manoeuvres.
    
    Ted Molczan
    
    
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