The launch took place on May 23 at 8.36 UTC and the satellite will probably be called Kosmos-2588. The Soyuz-2.1b flew a trajectory typically used for launches into 67° inclination orbits, but the Fregat upper stage at some point changed the inclination to 73°. This was most likely done to avoid the use of new drop zones on Russian territory (the 73° inclination hasn't been used from Plesetsk in decades). The inclination change had been predicted on the basis of stage drop zones by Dillon Shropshire in the related thread "Upcoming Russian Military Cosmos Launch". http://www.satobs.org/seesat/May-2025/0099.html However, the orbit is much lower than predicted, namely 464x480 km. The orbit is reminiscent of that of the US electro-optical reconnaissance satellites USA 280 and USA 338. Marco Langbroek kindly responded to my request to calculate the current orbits of the American satellites and it turns out the new Russian satellite is nearly co-planar with USA 338 (2022-117A, NORAD 53883). Kosmos 2588 464 x 481 km 1 64095U 25109A 25143.55933395 -.00000077 00000-0 00000+0 0 9992 2 64095 72.9781 11.2707 0012011 240.5421 205.8561 15.31087914 30 USA 338 402 x 408 km 1 53883U 22117A 25143.55933391 0.00015160 00000-0 23433-3 0 07 2 53883 73.5909 11.3830 0004038 237.5250 33.4145 15.53961352 07 There is little doubt that this is the fifth mission flown under a project known as Nivelir, one goal of which is to make long-distance observations of US reconnaissance satellites. The first Nivelir satellite (Kosmos-2519) used a Russian reconnaissance satellite as a target, but subsequent ones (Kosmos-2542, 2558 and 2576) have been co-planar with US reconnaissance satellites. In addition to that, Kosmos-2519 and 2542 both released a subsatellite which in turn fired what the Pentagon believes is an ASAT projectile. It is not known if these subsatellites are on board Kosmos-2558, 2576 and 2588. More on the current mission in this thread on the NASA Spaceflight Forum: https://forum.nasaspaceflight.com/index.php?topic=62904.0 And here is a two-part article on the Nivelir project that I recently wrote for The Space Review: https://www.thespacereview.com/article/4979/1 https://www.thespacereview.com/article/4982/1 Bart Hendrickx _______________________________________________ Seesat-l mailing list https://lists.seesatmail.org/mailman/listinfo/seesat-lReceived on Fri May 23 2025 - 16:22:03 UTC
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