The flyby of USA 326 by Kosmos 2558 on August 4: a post-analysis

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In a previous post I discussed the launch of Kosmos 2558 (2022-089A), a Russian military satellite which was launched from Plesetsk on August 1, 2022. 

As I pointed out, it was inserted into the same orbital plane as the American classified military satellite USA 326 (2022-009A, an electro-optical reconnaissance satellite launched in February 2022), at an orbital altitude only a few tens of kilometers below it. 

And that was probably no coincidence: Kosmos 25578 is likely an 'inspector' satellite meant to surreptitiously check out USA 326.

 

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The two satellites had a relatively close flyby on August 4. I did a post-encounter analysis based on orbits from before and after the flyby, to assess the time and the distance of the flyby.

I find that the close flyby happened near 14:16:27 UTC (August 4, 2022), give or take a few seconds, at a nominal distance of ~67 km. Most of that distance (about 64 km) is in altitude. 

The flyby happened in daylight near 42.3 N, 25.9 W, over the mid-Atlantic, while both objects were southbound. USA 326 was at an altitude of about 518 km at that time, and Kosdmos 2558 at an altitude of about 453km.

Below is an animation of the flyby, as seen from two viewpoints (first lateral, than oblique):

 

~67 km is a clear safe distance and therefore no cause for worry (although it worried some generals in the Pentagon perhaps), but nevertheless close enough to make it interesting. I strongly suspect that Kosmos 2558 was imaging USA 326 at the time, in an attempt to gather information on the character of the satellite.

The diagram below gives the distance with time between Kosmos 2558 and USA 326 around the time of the approach.

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It will be interesting to follow the two objects and see whether a new flyby happens at some point. In a previous similar case in early 2020, another Kosmos satellite, Kosmos 2542, was sent to check out the US military satellite USA 245, and released a second satellite, kosmos 2543, that chased the US satellite for a while.

 

Added comment:

Fred Jansen made a pertinent remark: from launch to operational in a mere 3 days would be awfully fast.
Another issue, brought up by Allan Thomson, is that the Sun-Kosmos 2558-USA 326 angle was quite low during this encounter, which is  not ideal.

However, as the two objecst share the same orbital plane, these encounters repeat at intervals: so even if it was not ready and fully operational yet during this approach, there will be other opportunities in the future. It will be interesting to see whether Kosmos 2558 will raise its orbit at some point, or will do other manoeuvres to keep the precession of its RAAN in line with that of USA 326.

(Note: the orbital elements for USA 326 used in this analysis are based on optical tracking data by an international group of  Independent Space Observers, including myself, Cees Bassa and Russel Eberst)

Close Encounters of the Classified Kind

The Space Review has just published my paper on the close ISS flyby of US spy satelllite USA 279.

OT: Near Earth Asteroid 2012 LZ1 fly-by imaged, June 15

On June 10, 2012, Australian Siding Spring astronomer Rob McNaught and colleagues discovered a bright Near Earth Asteroid (NEA). It got the provisional designation 2012 LZ1 and turned out to be large: it is estimated to be about 500 meter in diameter (UPDATE 22 June 2012: radar observations from Arecibo obtained during the fly-by actually showed it to be twice as large, i.e. 1 km diameter! This suggests a low albedo, which might imply a carbonaceous composition). It made it's closest approach to the earth/moon system around midnight of June 14/15. With a pass distance of 5.3 million km (a multitude of the Earth-Moon distance), this flyby was not particularly close. But because the asteroid is large, it became quite bright, ~ mag. +13.

In the early morning of June 15, some 9 hours after closest approach, I used the "remote" 37-cm F/14 Cassegrain of UoI Rigel observatory at Sonoita, Arizona, USA (MPC 857, the same telescope that I often use to image geostationary satellites)  to image the asteroid (I also obtained some imagery using the larger 61-cm telescope of Sierra Stars Observatory in California).

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The image above is a stack of 4 CCD images, each of 30 second exposure and spaced 5 minutes in time, obtained with the Rigel telescope. The asteroid can be seen as a set of 4 short trails lining up. It was moving at a rate of about 35"/minute near the Aquila-Capricorn border at that time and was near mag. +13.