Soyuz-2.1v - Kosmos-2574, Razbeg №1, MKA-V - Plesetsk, 43/4 - December 27, 2023 (07:03:44 UTC)

[B. Hendrickx]

Kosmos-2574 and Kosmos-2575, which are in the same orbital plane, seem to be getting ready for a close encounter shortly. Their initial post-launch orbit parameters were virtually identical (349x360 km), but Kosmos-2574 is now orbiting roughly 10 kilometers below Kosmos-2575 due to slow orbital decay and a series of small maneuvers it has made in the past three weeks or so (Kosmos-2575 has so far not made any orbit corrections). Their current altitudes are:
Kosmos-2574: 338x347 km
Kosmos-2575: 348x358 km

After the launch of Kosmos-2575 on February 9, the two satellites were at a considerable distance from one another (almost on opposite sides of the Earth), but since Kosmos-2574 is in a slightly lower and hence faster orbit, it has slowly been getting closer to Kosmos-2575. If no significant changes are made to the orbits of these satellites in the coming day, Kosmos-2574 will catch up with Kosmos-2575 and overtake it on February 21. Because of the low relative velocity, this is a slow process that will see the two satellites fly relatively close to each other for several hours. I’m not sure how close exactly they will get. It’s interesting though that the apogee of Kosmos-2574 is very close to the perigee of Kosmos-2575.

This doesn't look like typical behavior for a pair of co-planar remote sensing satellites. These usually have almost exactly the same perigee/apogee, maintaining the same distance from one another to ensure that they pass over any given region with the same interval. That is, for instance, what’s being done with the two co-planar Bars-M topographic mapping satellites (Kosmos-2556 and 2573).  In other words, it’s still too early to conclude that Kosmos-2574 and 2575 are the first two Razbeg optical reconnaissance satellites.

Some reports in recent days have linked Kosmos-2575 to the Russian nuclear space weapon that’s been causing a lot of commotion in Washington. However, the only foundation for that speculation seems to have been the fact that it was the most recently launched Russian military satellite, nothing more. Several days before the launch of Kosmos-2574 in December a usually reliable source on a Russian space forum did cryptically call it a “death star”, a reference to the space weapon in Star Wars. Hard to say though how credible that information is. As usual, we’ll just have to wait and see what these satellites do in the coming days and weeks to draw any more definitive conclusions about their missions. 

[B. Hendrickx]

The latest info is that unless further orbit adjustments are made the closest approach between Kosmos-2574 and 2575 will be tomorrow around 16.00 UTC. Their orbits are not entirely coplanar (there is still a 0.7° angle between them) and the closest distance will be several tens of kilometers, so not that close.

[B. Hendrickx]

These graphs posted on the "Novosti kosmonavtiki" forum show the mutual distance (in km) between Kosmos-2574 and 2575 as well as their relative velocity (in km/s) in the coming hours. Based on yesterday's Two Line Elements, the closest distance will be 26 km at 15.42, so no indications that there will be any direct physical interaction between the two satellites.

[B. Hendrickx]

Jonathan McDowell on X:

A debris object (59022) has been cataloged coming off the Kosmos-2574 satellite (whose low orbit mission is unclear). It separated late on Feb 23. Worth noting, although likely unrelated, is a close pass to the satellite by Kosmos-2575 on Feb 21 around 1400 UTC.

The object (with the international designation 2023-209C) appeared on SpaceTrack today and is not yet identified as debris there. However, it is quickly losing altitude, strongly suggesting it is a low-density piece of debris rather than a subsatellite. The altitudes calculated from the two available TLEs are: 
24 Feb 2024 18:08: 324.6 х 339.0 km
25 Feb 2024  9:37:  321.1 х 335.9 km

Kosmos-2574 itself  is currently in a 334x345 km orbit. Robert Christy (orbitalfocus.uk) estimates the object separated from Kosmos-2574 "around February 22", somewhat earlier than what Jonathan McDowell writes. Kosmos-2575 has still not maneuvered and is in a 348x356 km orbit.

Even though the recent encounter between Kosmos-2574 and 2575 was relatively distant, the appearance of this object so soon afterwards may not at all be coincidental. Again, this is not typical behavior for an optical reconnaissance satellite. No such debris shedding events have been observed for other Russian reconnaissance satellites in the recent past. Moreover, if this were some kind of protective cover for an optical system, why wait to eject it until almost two months after launch?

It'll be interesting to see if any more debris is catalogued in the coming days. This is often a gradual process.
 

[B. Hendrickx]

Another distant encounter between Kosmos-2574 and 2575 is taking place in the coming hours. Kosmos-2574 has been showing a pattern of natural decay interspersed with small burns to further lower its orbit. Kosmos-2575 has not maneuvered yet (see the graph made by Robert Christy last week). The current altitudes are:
Kosmos-2574: 325x338 km
Kosmos-2575: 346x356 km

Kosmos-2574's lower and faster orbit will bring it in the vicinity of Kosmos-2575 on a regular basis. There can be little doubt that there is some kind of relation between the two satellites, but what exactly that is remains open to speculation.

Meanwhile, the object that separated from Kosmos-2574 shortly after the previous encounter between the two satellites in late February re-entered around March 5. 

[B. Hendrickx]

Kosmos-2574 re-entered on November 15 following a mission lasting nearly two years. After having a reached a peak altitude of about 350 km last March, the satellite stopped making maneuvers and its orbit had been gradually decaying ever since. Its mission was clearly correlated with that of Kosmos-2575, which was launched into the same orbital plane (see the attached graph made by Marco Langbroek). Meanwhile, Kosmos-2575's orbit is being meticulously maintained at an average altitude of 344 km. Exactly the same is being done with Kosmos-2578, ensuring that the two pass over the same general region of Earth with a 45-minute interval. Their orbital planes are spaced about 5° apart, as a result of which they have significantly different viewing angles.

Kosmos-2574 is indicated in the thread heading as "Razbeg N°1/MKA-V", but this should be removed because it has become quite clear by now that it did not belong to that project, which is most likely yet to see its first launch. Kosmos-2574 appears to be one in a series of 12 low-orbiting imaging satellites that Russia has launched since September 2021 and that are known only by the names EO MKA and OO MKA ("prototype of a small satellite"). The twelve satellites are Kosmos-2551, 2555, 2560, 2568, 2574, 2575, 2577, 2578, 2591, 2592, 2593 and 2594.