Richard Miles, who observes minor planets, imaged the payload of NROL-24 over a wide arc. He has kindly reduced his observations into the MPC reporting format: http://satobs.org/seesat_ref/misc/MPCReportA.txt For ease of use by our analysts, I have converted them to the U.K. format: http://satobs.org/seesat_ref/misc/Richard_Miles.txt http://www.satobs.org/position/UKformat.html Richards site coordinates are 50.9310 N, 2.4053 W, 72 m. For my internal use, I have assigned a site number of 9011, which appears in above U.K. format file. Combining Richard's and Peter Wakelin's observations yields the following elements for the payload, with excellent residuals: 1 32378U 07060A 07344.98097734 .00000000 00000-0 00000-0 0 04 2 32378 60.0096 318.1644 5542864 286.8880 21.5711 4.77472119 06 Arc 2007 Dec 11.01 - 11.13, WRMS residuals = 0.009 deg The orbit is 261 X 16775 km, inclined at 60 deg, with a period of 301.6 min. The objects from this launch have yet to appear in the public catalogue; however, the international designator can only be 07060A. I have speculatively assigned the next available catalogue number, 32378. As is often the case soon after a launch, we have yet to reach consensus as to which object is the payload and which is the rocket body. I agree with Daniel Deak that the payload is the object that appeared to be within the Centaur's propellant dump cloud, and the Centaur was the one that appeared well clear of it. In fact, neither object was within the cloud, but the payload happened to be in line with it and the observer. Richard reported his single Centaur and 47 payload points in agreement with this interpretation. Peter Wakelin's identifications are the reverse. Scott Campbell and Mike McCants have produced accurate elements for what I believe to be the Centaur (Mike labelled it as the payload), which differ from those of the payload mainly in the inclination and RAAN: 1 99999U 000000 07344.98098874 0.00000172 00000-0 50000-4 0 08 2 99999 60.7019 318.7838 5501400 285.6245 22.3875 4.77454958 05 1 32378U 07060A 07344.98106975 .00000000 00000-0 00000+0 0 01 2 32378 60.7184 318.7781 5536000 286.5100 21.8181 4.77400000 00 It makes sense to me that the payload would have a nice round numbered inclination, i.e. 60.0 deg, and that the Centaur would end up in 60.7 deg, as a result of its CCAM (collision and contamination avoidance manoeuvre) and subsequent venting. If the payload behaves like that of NROL-1, then it will manoeuvre to a Molniya orbit within about one week of launch. The initial orbital plane is about 16 deg east of the 90028 / 04846A Molniya object that I and others expected NROL-24 to target for replacement. I am surprised to see such a wide planar separation, so perhaps the 90028 replacement theory needs to be reconsidered. Note that due to their different rates of precession, NROL-24 would overtake the plane of 90028 in about 41 days, but that seems a long time to wait in the intermediate orbit. Perhaps the plane will be shifted west as part of the manoeuvres to Molniya; I have not analysed this possibility. Ted Molczan ------------------------------------------------------------------------- Subscribe/Unsubscribe info, Frequently Asked Questions, SeeSat-L archive: http://www.satobs.org/seesat/seesatindex.html
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