RE: Optical 31 Dec 2011

From: Ted Molczan (ssl3molcz@rogers.com)
Date: Mon Jan 02 2012 - 04:58:39 UTC

  • Next message: Ted Molczan: "RE: Optical 31 Dec 2011"

    Greg Roberts wrote:
    
    > NOTES:
    > -------
    > (1) Thanks to the efforts of Mike and Ted the bright unknown has now been
    >     identified as IGS 7 #37954 11-075A.
    
    After some study, I have concluded that our identification of Greg's bright unknown of Dec 29 UTC as IGS 7 was
    incorrect. The object reported as 11075A is the rocket of IGS 5A (09066B / 36105). The following orbit is an excellent
    fit to Greg's observations of Dec 29-31 UTC, and also correlates closely with the last known orbit, based on
    observations about 3 months ago:
    
    IGS 5A r                                                 536 X 589 km
    1 36105U 09066B   11365.85988510  .00000000  00000-0  00000-0 0    09
    2 36105  97.5804  66.3617 0038181 332.1842  27.7339 15.00584881    04
    Arc 20111229.85-1231.92 WRMS resid 0.019 totl 0.008 xtrk
    
    Here are the observations, with the correct ID:
    
    36105 09 066B   0433 F 20111229202531100 56 15 1212251-560219 39  +030 05
    36105 09 066B   0433 F 20111229202531100 56 15 1212251-560219 39  +030 05
    36105 09 066B   0433 F 20111229202533700 56 15 1209282-560149 39  +030 05
    36105 09 066B   0433 F 20111229202533700 56 15 1209282-560149 39  +030 05
    36105 09 066B   0433 F 20111229202536300 56 15 1206549-560122 39  +030 05
    36105 09 066B   0433 F 20111229202536300 56 15 1206549-560122 39  +030 05
    36105 09 066B   0433 F 20111229202538600 56 15 1215063-560233 39  +030 05
    36105 09 066B   0433 F 20111229202538600 56 15 1215063-560233 39  +030 05
    36105 09 066B   0433 F 20111229202539400 56 15 1203261-560129 39  +030 05
    36105 09 066B   0433 F 20111229202539400 56 15 1203261-560129 39  +030 05
    36105 09 066B   0433 G 20111230202630000 18 15 1131160-553354 39  +020 05
    36105 09 066B   0433 G 20111230202635000 18 15 1124020-551933 39  +020 05
    36105 09 066B   0433 G 20111230202640000 18 15 1116470-550400 39  +020 05
    36105 09 066B   0433 G 20111230202640200 56 15 1116456-550809 39  +020 05
    36105 09 066B   0433 G 20111230202646000 18 15 1109080-544450 39  +020 05
    36105 09 066B   0433 G 20111231202547700 56 15 1245331-561240 39  +015 05
    36105 09 066B   0433 G 20111231202643800 56 15 1144079-560408 39  +015 05
    36105 09 066B   0433 G 20111231202711300 56 15 1104542-544152 39  +020 05
    36105 09 066B   0433 G 20111231202732400 56 15 1031447-523839 39  +025 05
    36105 09 066B   0433 G 20111231202752800 56 15 0958169-493211 39  +025 05
    36105 09 066B   0433 G 20111231220330000 56 15 2322545-312955 39  +045 05
    36105 09 066B   0433 G 20111231220341400 56 15 2330410-291027 39  +045 05
    36105 09 066B   0433 G 20111231220348700 56 15 2335277-274004 39  +045 05
    
    The confusion arose in part because, Greg spotted what he thought was 09066B on Dec 24 UTC, which turns out to have been
    05042A / 28888. Greg expected 05042A at about 23:07 UTC, but it failed to appear, which alerted him (and us) that it
    must have manoeuvred since the previous observation, by Tony Beresford, on Dec 13 UTC. Greg did not realize that the
    object he observed at 22:31 UTC, and reported as 09066B, was in fact 05042A. Their planes were sufficiently close to
    mistake one for the other, which is a common type of problem.
    
    This was 05042A's pre-manoeuvre orbit:
    
    USA 186                                                  253 X 987 km
    1 28888U 05042A   11347.47987517  .00031380  00000-0  26508-3 0    01
    2 28888  97.8879  47.7555 0523876  80.3861 285.6115 14.82040127    01
    Arc 20111206.85-1213.54 WRMS resid 0.126 totl 0.101 xtrk
    
    Here is the post-manoeuvre orbit, based on Greg's observations during Dec 24-29 UTC:
    
    USA 186                                                 256 X 1023 km
    1 28888U 05042A   11364.82944495  .00018503  00000-0  16863-3 0    02
    2 28888  97.8771  64.7923 0546213  24.1506 338.4302 14.75914571    02
    Arc 20111224.86-1230.89 WRMS resid 0.062 totl 0.011 xtrk
    
    Here are the observations of Dec 24, with their correct ID:
    
    28888 05 042A   0433 G 20111224203130400 56 15 1147235-615211 39  +040 05
    28888 05 042A   0433 G 20111224203135000 56 15 1141276-615551 39  +050 05
    28888 05 042A   0433 G 20111224203146700 56 15 1125490-615844 39  +045 05
    28888 05 042A   0433 G 20111224203158700 56 15 1107589-615321 39  +040 05
    
    The orbits nearly intersect on 2011 Dec 15 at 12:26 UTC, at perigee, which I take to be the time of the reboost
    manoeuvre.
    
    So, IGS 7A (11075A / 37954) and its rocket have yet to be found. I offer the following search elements, which are based
    on the initial orbit of its predecessor in Japan's western imaging reconsat plane, 03009B / 27699:
    
    1 70000U          11346.36282681  .00000000  00000-0  00000-0 0    01
    2 70000  97.3700  53.6970 0002000 265.0000  95.0000 15.26000000    42
    
    A full planar search likely will be required to find both objects. The orbit appears not to be well placed (marginal)
    for Greg, so the discovery could be delayed for some time.
    
    Ted Molczan
    
    
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