RE: NROL-49 search elements

From: Ted Molczan (
Date: Sat Jan 22 2011 - 13:30:59 UTC

  • Next message: Ted Molczan: "RE: NROL-49 search elements"

    Bob Christy's radio observations now total 5 passes spanning 15 revs, ending early Jan 22, near
    00:23 UTC.
    The larger data set leads me to this approximate solution:
                                                             251 X 994 km
    1 72001U          11020.92423333  .00008569  00000-0  70000-4 0    05
    2 72001  97.9000 135.1447 0530280 257.4692  96.4311 14.81221067    01 
    At least until successive solutions shows signs of convergence, they should be treated with
    suspicion - expect large time and track errors.
    This one is far removed in argument of perigee from the earlier ones. It happens to be close to the
    argument of perigee of the spacecraft that USA 224 (11002A / 37348) will replace, USA 161 (01044A /
    26934), so it seems reasonable for it to closely match its orientation elements. 
    That did not always happen on previous KH launches, but those employed the Titan 4, the final stage
    of which could not be restarted. The restartability of Delta 4 Heavy's final stage offers much
    greater flexibility in argument of perigee - what cannot be achieved by direct insertion, can be
    achieved by inserting into a parking orbit at the intended perigee altitude, coasting to the
    required latitude of perigee, and then firing again to raise the apogee.
    I expect to be unavailable from approximately 16:00 UTC until perhaps 03:00 UTC.
    Ted Molczan
    Seesat-l mailing list

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