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 _______________________________________________ Seesat-l mailing list http://mailman.satobs.org/mailman/listinfo/seesat-l
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