RE: NROL-39 search elements

From: Ted Molczan (
Date: Fri Dec 06 2013 - 19:23:39 UTC

  • Next message: Ted Molczan: "RE: NROL-39 search elements"

    We have received observations and elements of the primary payload off-list, which reveal that the Centaur yaw-steered
    into orbit with a RAAN ~5 deg east of my 78802 TLE estimate, that was derived from a previous launch. It appears that
    the RAAN (right-ascension of the ascending node) is almost exactly midway between those of the first two FIA Radar
    satellites, as Cees Bassa suspected might happen. Further tracking is required to determine the precise RAAN.
    Here is the resulting TLE that I received:
    1 78817U          13340.34743573  .00000031  00000-0  50000-4 0    04
    2 78817 122.9957 225.7024 0008930  69.2445 293.3670 13.47211804    01
    Greg Roberts just reported that he was able to easily acquire the object using this TLE, and it was reasonably on time,
    but off a little in track. Greg is still observing, working to spot the Centaur, which may prove more of a challenge.
    Good luck Greg!
    Prospective observers should use the 78817 TLE. My pre-launch 78802 TLE should be abandoned, since it will produce
    predictions with huge track errors, that will almost certainly result in missing the object.
    I expect to be unavailable for some of the period from ~22:00 UTC to ~02:00 UTC. Upon my return, I will analyze
    observations that may be reported during that time, but I would be pleased to find that another list member took care of
    the task to maintain the flow of data to other observers.
    Ted Molczan
    Seesat-l mailing list

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