Cees Bassa wrote: > The 99733/23658A unknown was seen again. These observations can be > connected to the June 7 observations with the following 263 x 1032 km > _at_ 97.93 deg orbit: > > USA 224 candidate > 1 99733U 23658A 23158.02219900 .00000000 00000-0 50000-4 0 09 > 2 99733 97.9305 294.0898 0547630 284.3456 131.1547 14.74334761 05 > # 20230607.02-20230613.06, 14 measurements, 0.004 deg rms > > There is no obvious match to the 99735/23663A unknown. A circular > orbit fit yields a low orbit: 323 km _at_ 97.4 deg. I am confident that Cees has recovered USA 224 (11002A / 37348), now in a new plane. During its primary mission, USA 224 operated in the eastern KH-11 plane. It maintained MLTAN (Mean Local Time of Ascending Node), between 00:52 hours and 01:05 hours, with a mean of 00:58 hours. In 2021, it began to drift eastward. This was accomplished by allowing its orbit to decay, hastened by at least three (3) small orbit-lowering manoeuvres in late 2021, detected by Nico Janssen. By day 22221.99742264, its mean motion was 15.18127660 rev/d, and its MLTAN was 02:22:41. On day 22261.06005200, Nico detected it in a higher orbit, with mean motion 14.99182926 rev/d. MLTAN was 02:30:14. It was last observed by Nico on day 22271.06970500 in the same orbit, with MLTAN of 02:31:37. Cees has recovered it in a 14.74334761 rev/d sun-synchronous orbit, with MLTAN of 02:35:44. USA 116 provides a rough historical precedent. Like USA 224, during its primary mission it operated in the eastern KH-11 plane. It maintained MLTAN between about 00:54 and 01:04, with a mean of 00:59. Following the launch of its replacement (USA 161 01044A/ 26934) in October 2001, its orbit was allowed to decay, causing it to drift eastward. USA 116 reached USA 224's present MLTAN of 02:35 on 2006 Dec 18 UTC. It was last seen on day 08323.69802823, in a 14.83044340 rev/d orbit, with MLTAN 02:53:38. Ted Molczan _______________________________________________ Seesat-l mailing list https://lists.seesatmail.org/mailman/listinfo/seesat-lReceived on Tue Jun 13 2023 - 06:26:08 UTC
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