Kevin Fetter observed an UNID that I have identified as Essaim 3 E24 (04049E / 28496): http://satobs.org/seesat/Feb-2013/0024.html Kevin intended to post his observations, but seems to have forgotten to include them. Here is the TLE he fit to them: 1 99999U 13035.96631388 .00000400 00000-0 50000-4 0 07 2 99999 98.3168 65.2854 0011742 315.8390 91.9980 14.82402441 02 Greg Roberts spotted the same object last July, which he suspected was 83060C / 14139. Here are his observations, with the correct ID: 28496 04 049E 0433 F 20120713174806650 55 15 1307007+244228 19 28496 04 049E 0433 F 20120713174816796 55 15 1305495+265204 19 28496 04 049E 0433 F 20120713174821854 55 15 1305103+275252 19 28496 04 049E 0433 F 20120713174831916 55 15 1304041+294626 19 When Kevin posts his observations, it may be possible to improve his orbit, by including Greg's observations. I based my identification on the orbits of the four Essaim satellites following their decommissioning in 2010 October, as reported in the following paper: http://www.spaceops2012.org/proceedings/documents/id1266472-Paper-001.pdf The results for each satellite are appended to this message. There are three TLEs per satellite. The first is the last known orbit prior to decommissioning, derived from hobbyist observations. The second is the result of propagating the first orbit to the approximate time of the final decommissioning manoeuvre, using Mike McCants' int2 program, and then assuming instantaneous change to the final eccentricity and mean motion. The third TLE is the result of propagating the second one to the approximate epoch of Kevin's observation, using int2. Since the second and third TLEs are estimates, their catalogue number has been altered to reduce the risk of their being mistaken for TLEs from observations. The propagated Essaim 3 E24 TLE is very similar in RAAN and mean motion to the one Kevin derived from his observations. I recommend using Kevin's TLE to recover Essaim 3, since it should be reasonably predictive. Mine is not predictive, so should not be used for the recovery. I used int2 for the propagations because it accurately models solar gravity perturbations, which significantly affect sun-synchronous orbits. If I understood the above paper correctly, the Essaim are in frozen orbits, with argument of perigee near 270 deg. Int2 appears not to propagate frozen orbits reliably, and I made no effort to adjust the final results. The remaining three objects could be discovered using my propagated elements, by means of a planar search. My estimated TLEs are not predictive, so a planar search absolutely is required. I would not be surprised if one or more have been spotted in recent years as UNIDs, so if time permits I may check past UNIDs for correlations. Ted Molczan Essaim 1 W23 1 28494U 04049C 10078.14364266 .00000000 00000-0 00000-0 0 05 2 28494 98.2800 46.2358 0003758 100.0011 260.1619 14.70167000 01 1 78494U 04049C 10287.29238483 .00000600 00000-0 88972-4 0 03 2 78494 98.3033 259.0155 0011630 158.8992 200.9893 14.75120000 01 1 78494U 04049C 13035.97110678 .00000664 00000-0 96694-4 0 07 2 78494 98.3493 50.2927 0010213 349.7093 10.2637 14.75942268 04 Essaim 2 W11 1 28495U 04049D 10078.14410210 .00000000 00000-0 00000-0 0 07 2 28495 98.2800 46.1004 0004638 90.0000 270.1725 14.70167382 05 1 78495U 04049D 10280.35064607 .00000650 00000-0 89651-4 0 09 2 78495 98.3014 251.8087 0010460 170.8296 189.0669 14.78225000 03 1 78495U 04049D 13035.97860405 .00000581 00000-0 78528-4 0 02 2 78495 98.3421 54.3392 0011107 325.9098 33.9985 14.79086885 07 Essaim 3 E24 1 28496U 04049E 10091.34792659 .00000000 00000-0 00000-0 0 05 2 28496 98.3090 64.3581 0010000 59.4702 300.7489 14.70158874 01 1 78496U 04049E 10279.39896266 .00000700 00000-0 90150-4 0 08 2 78496 98.3271 256.2958 0012500 185.4986 174.3864 14.81100000 00 1 78496U 04049E 13035.99698442 .00000572 00000-0 72199-4 0 03 2 78496 98.3402 65.3759 0009522 325.9896 33.9291 14.81989447 09 Essaim 4 E12 1 28497U 04049F 10091.34746670 .00000000 00000-0 00000-0 0 08 2 28497 98.3146 64.4169 0013000 49.4724 310.7611 14.70158768 03 1 78947U 04049F 10287.29352680 .00000650 00000-0 93066-4 0 07 2 78947 98.3348 264.5546 0012000 150.6790 209.2677 14.76620000 04 1 78497U 04049F 13035.95143143 .00000803 00000-0 11237-3 0 05 2 78497 98.3547 60.1610 0014283 336.1683 23.7514 14.77626980 07 _______________________________________________ Seesat-l mailing list http://mailman.satobs.org/mailman/listinfo/seesat-l
This archive was generated by hypermail 2b29 : Wed Feb 06 2013 - 05:00:18 UTC