Tuesday, 2 August 2022

Kosmos 2558, a Russian inspector satellite targetting the US IMINT satellite USA 326?


click image to enlarge

On August 1, 2022, at 20:25 UTC, Russia launched a Soyuz 2.1v carrying a military satellite from Plesetsk into a Polar orbit. It has since been catalogued under nr 53323 (COSPAR ID is 2022-089A). It will probably receive the designation Kosmos 2558

Directly after launch it was in a 435 x 452 km, 97.25 degree inclined orbit. The Volga upper stage was catalogued in a 284 x 425 km orbit.

Before the launch, there was a rumour that this was another 'inspector' satellite - a snooping satellite meant to covertly inspect another satellite. After some speculation about the potential target arose, I pointed out that the middle of the launch window as indicated by NOTAM's for the launch, 20:30 UTC, was close to the moment that the orbital plane of the classified US electro-optical IMINT satellite USA 326 (2022-009A) passed over Plesetsk, at 20:25 UTC

And sure enough, it did indeed launch at 20:25 UTC, into the orbital plane of USA 326. And as it turned out, into an orbital altitude that is close as well.

The apparent target, USA 326, was launched in February and is widely believed to be a new generation electro-optical IMINT satellite. It moves in a 97.4 degree inclined, 489 x 518 km sun-synchronous polar orbit. 

The RAAN of the newly launched Kosmos 2558 matches the RAAN of USA 326 closely, with a difference of only 0.04 degree (changing by about 0.01 degree/day). The close correspondance of the two orbital planes can be seen in the diagram above. The orbital altitude of Kosmos 2558 is about 60 km lower than that of USA 326, but that might change if any post-launch manoeuvres are done the coming days and weeks.

With the current orbit, Kosmos 2558 will make a relatively close approach to USA 236 at August 4 near 14:47 UTC. The approach distance is ~75 km, almost all of that (73 km) is in altitude.

 [EDIT: a post-encounter analysis on 6 Aug 2022 based on orbits closer to the approach moment gives 4 August ~14:16:27 UTC for the approach, and a nominal distance of 67 km, most of this in altitude]

In early 2020, Russia did something similar with Kosmos 2542/2543, directing it towards the KH-11 electro-optical reconnaissance satellite USA 245.

It will be interesting to follow both satellites the coming weeks, to see what happens.

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