Michael Thompson

Prior to its most recent set of maneuvers, it was still in the same plane as USA 245, but its period was offset such that there were only relatively close passes every 11-12 days.

(Note that any two satellites in the same plane with offset periods will have passes like this at some regular cadence. It's enough to raise suspicion, but not prove anything.)

Although the range oscillates, the relative orbit is phased such that the closest distance is when the satellites are in sunlight (i.e. visible to optical observation) and the furthest distance is when both satellites are in eclipse.

When 2542 was launched, Russia said that only Russian satellites would be inspected, but the only ones in this orbital plane are Cosmos 2523 (a previous inspection satellite), Cosmos 2543 (an earlier deployed sub-satellite), and Resurs-P1 (a commercial remote sensing satellite).

While they are in the same plane, the passes are typical of any two satellites in the same plane: taking place at a distance of a few hundred km every few days. Not in consistent view, and the most recent maneuvers did nothing to improve the viewing geometry with any of these.

Personally, I think the intelligence value of observations of optical spy satellites like this one are probably marginal. Their mirror dimensions are publicly known, and from there, it's just basic optics to calculate approximate capabilities.

This is all circumstantial evidence, but there are a hell of a lot of circumstances that make it look like a known Russian inspection satellite is currently inspecting a known US spy satellite.

A pretty thorough look of the satellite catalog can't produce another potential target that looks as good as this in terms of the orbits and viewing geometry. (End)

A much needed follow up to this thread, as it ended up with much more exposure than I expected. The orbital elements for USA 245 were formulated and based on observations made by @HAMSATNL and shared through the SeeSat community. http://www.satobs.org/seesat/Jan-2020/index.html …

Additionally, if you look at the email threads there, @HAMSATNL, @cgbassa, Björn Gimle, and Ted Molczan have all been discussing a possible relationship between Cosmos 2542/2543 and USA 245 during January.

They've all been doing this kind of analysis for longer than me, and have been very helpful for myself and others who have only been spinning up on satellite tracking in the more recent years.

And probably one last set of updates for a while, as @coastal8049 and @HAMSATNL have both provided additional observations on USA 245. The original analysis used the same orbit for USA 245 throughout because it was the only one I had on hand.

The orbit for USA 245 now uses: 1. An orbit estimate from January 31st from @HAMSATNL: http://www.satobs.org/seesat/Jan-2020/0008.html … 2. An orbit estimate from January 20th posted by @coastal8049: https://twitter.com/coastal8049/status/1219889619187027968?s=20 … 3. An orbit estimate from HAMSATNL from January 28th posted to his website.

Some initial analysis estimates that USA 245 made its maneuver on January 23rd, just 1 day after Cosmos 2542 synchronized its period, but with sparse state estimates like these, it's hard to make a solid match on just one epoch.

But to sum it up, with the additional observations, we can see that Cosmos 2542 probably only was close to USA 245 for a few days at most before 245 made a maneuver to start to drift away.