Re: Kosmos 2542/2543 vs USA 245?

I took a quick look at this tonight because I had some free time.

I do see that using the pre-maneuver TLE that you provided, Kosmos 2543 was set to have multiple close passes to USA 245, with the closest ones coming on Dec 9, as close as ~55km away.   The timing of the USA 245 maneuver is interesting to say the least.

Kosmos 2543 made a small maneuver on Dec 9th followed by the larger ones you reference on Dec 14th and 16th.  You would think that if a "chase" is going on, that would be enough time to get a good fix on the new position of USA 245.

It's a really interesting observation, especially if USA 245 can be re-acquired in an orbit up near where Kosmos 2543 has headed.

As a note of comparison, Cartosat-3, which is also in the same plane, only has passes as close as around 150km, and most are in the 300-400km range.  That's just one data point, but it was certainly going to get closer to USA 245.

Michael Thompson
________________________________
From: Seesat-l <seesat-l-bounces+thomp376=purdue.edu_at_satobs.org> on behalf of Scott Tilley via Seesat-l <seesat-l_at_satobs.org>
Sent: Friday, December 27, 2019 4:36 PM
To: Tim Collins <twcc_at_btinternet.com>
Cc: seesat-l_at_satobs.org <seesat-l_at_satobs.org>
Subject: Re: Kosmos 2542/2543 vs USA 245?

Hi All

There are also many other missions (Cartosats, Jinlin etc) in almost the same plane so claiming it’s targeting USA 245 is a stretch until we see specific behaviour.

It could also be some sort of image image intel mission itself And/or technology demonstrator.

Scott Tilley



Sent from my iPhone

> On Dec 26, 2019, at 07:19, Tim Collins via Seesat-l <seesat-l_at_satobs.org> wrote:
>
> Nico,
>
> The cat-and-mouse activities and orbital change would appear to be an unlikely coincidence.  Maybe the Kosmos is on a mission to get close to the NRO satellite and take photographs to demonstrate its non-Earth reconnaissance capabilities.  It would be illogical for the Kosmos to catch a friendly, ie another Kosmos, as (a) the resulting demonstration photographs if released could compromise Russian capabilities, and (b) if they hit there is a risk of losing two Russian assets.  Alternatively, maybe the chase is just a test of collision avoidance technologies.
>
> Clear skies and good luck with re-acquisition of 245.
>
> Tim C
> UK
>
>
> -----Original Message-----
> From: Seesat-l [mailto:seesat-l-bounces+twcc=btinternet.com_at_satobs.org] On Behalf Of Nico Janssen via Seesat-l
> Sent: 26 December 2019 14:56
> To: seesat-l_at_satobs.org
> Subject: Kosmos 2542/2543 vs USA 245?
>
>
> Kosmos 2542 was launched on 2019-11-25 into a 368x857 km orbit.
> Interestingly, its orbit plane is almost exactly the same as USA 245's
> orbit plane. The difference is less than 1 degree.
>
> On 2019-12-06 the inspector satellite Kosmos 2543 was deployed from
> Kosmos 2542. After some initial maneuvers near its 'mother' satellite
> Kosmos 2543 started raising its orbit.
>
> On 2019-12-09 or 2019-12-10 USA 245 changed its orbit. Before its
> maneuver it was in a 272x985 km orbit. This is the last TLE set that I
> could determine before the maneuver:
> USA 245
> 1 39232U 13043A   19342.41935900  .00010000  00000-0  10147-3 0 00
> 2 39232  97.8900  42.9218 0508960 301.2530 203.1441 14.80147872 09
>
> I lost track of USA 245 after its orbit maneuver. I suspect it is now in a
> much higher orbit.
>
> Kosmos 2542 is still in its original orbit. But meanwhile Kosmos 2543 has
> climbed to a 590x859 km orbit, still in the same orbit plane as USA 245.
>
> So what is going on? Is Kosmos 2543 chasing USA 245? And is USA 245
> trying to escape by changing its orbit? Or is all this just a coincidence?
>
>
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