Soyuz-2.1v/Volga - Kosmos 2558 - Plesetsk 43/4 - 1 August 2022 (20:25 UTC)

[Rondaz]

Update: obj. 53324 KOSMOS 2558 SL-4 R/B decay prediction: November 19, 2022 UTC 09h43mn ± 5h

https://twitter.com/jremis/status/1593747654277750790

[Rondaz]

Update: obj. 53324 KOSMOS 2558 SL-4 R/B decay prediction: November 19, 2022 UTC 09h43mn ± 1h

https://twitter.com/jremis/status/1593893959985668098

[B. Hendrickx]

As can be seen in the attached graphs from Celestrak, Kosmos-2558 continues to regularly perform small maneuvers, which are most likely intended to make sure that its orbital plane doesn’t drift away from that of USA 326, allowing it to make regular close passes to the US reconnaissance satellite. The latest maneuver took place earlier this month.

One big difference between Kosmos-2558 and its two predecessors (Kosmos-2519 and 2542) is that 5.5 months into its mission, it has not yet deployed a subsatellite. Kosmos-2519 and Kosmos-2542 released their subsatellites (Kosmos-2521 and Kosmos-2543) about two months and two weeks after launch respectively. Both subsatellites later fired what seem to have been high-speed projectiles when flying close to other Russian satellites.

The three most obvious explanations are that Kosmos-2558 does not carry a subsatellite, that the deployment failed for some reason (fairly unlikely) or that it is yet to be deployed. Another possibility is that it has been deployed, but is stealthy and has therefore not been spotted by US tracking assets. One of the known objectives of the Nivelir project was to outfit satellites with a radar absorbing coating. CNIIHM, the prime contractor for Nivelir, signed a contract for this with a company called NII Ferrit-Domen back in November 2016 (under the name Nivelir-RP). I wrote about this in the thread on the first Nivelir mission several years ago:
https://forum.nasaspaceflight.com/index.php?topic=43064.320
(see Reply 325)

Measures may also have been taken to make it difficult to spot the subsatellite with optical tracking systems. In fact, optical stealth technology may already have been tested by Kosmos-2536 (possibly also part of Nivelir), which was involved in rendezvous experiments with Kosmos-2535 in 2019-2020, but (unlike Kosmos-2535) was very difficult and sometimes impossible to see through telescopes used by amateur satellite observers.

If such a stealthy subsatellite has indeed been deployed, it does not seem to be transmitting at 2280 MHz, a frequency used by the earlier subsatellites to downlink telemetry. A search by European radio amateurs has turned up nothing on this frequency in the orbital plane of Kosmos-2558. However, a stealthy satellite would, of course, not be likely to transmit on a predictable frequency.