A so far unidentified object in GEO near PAN and Eutelsat Hot Bird 13B [UPDATED]

PAN on March 4, 2024 (click image to enlarge)

UNID near PAN on March 8, 2024 (click image to enlarge)

In the evening of March 8 I did some observations to check upon the drifting PAN/NEMESIS-1 satellite. To my surprise, there was another object there that is not in the current catalogue (as of 10 March 2024). It wasn't there yet when I imaged the area 4 days earlier, in the evening of March 4, as can be seen by comparing the two images above.

Most likely this UNID is some commercial geosynchronous satellite that has been relocated without the 18th STS having caught that move yet. But it could also be something new. For now, it remains unidentified.

The UNID is located at about 33.8 E longitude. A very provisional elset:

UNID ML080324
1 99999U 24000X   24068.68698391 0.00000000  00000-0  00000-0 0    03
2 99999   0.0001  87.9800 0002372 229.7255 130.2564  1.00270000    07

The object could perhaps be the newly launched Chinese satellite WHG-01 (2024-040A). It was launched from Xichang a week ago, on 29 February 2024. Currently (March 11, 2024), only an 8-day old GTO elset is available for the object. That elset combined with the elset for the UNID above suggests that the satellite could have been inserted into GEO at 33.8 E on March 6 near 11 UTC.

Over the half hour arc that I imaged it on March 8, the UNID remained stationary. 

PAN/NEMESIS-1 is meanwhile slowly drifting west (the drift can be seen in the images above too, by comparing the distance of PAN/NEMESIS-1 to EUTELSAT HOT BIRD B13), as it has been doing for quite a while now. On 2024 March 8 it was near longitude 33.45 E. It is currently drifting at a rate of approximately -0.03 degrees per day.

 

PAN longitude of subsatellite point over time (click diagram to enlarge)

NOTE: an initial mix-up of the names of two recently launched Chinese GEO sats was corrected.

 

UPDATE 14 March 2024:

Space-Track, since yesterday (first non-GTO TLE has epoch 24073.71736125 = 13 March 2024 17:13 UTC), finally also places an object  in this position, catalogue nr 59069, COSPAR 2024-040A. Provisionally named "Object A", but the Cospar code indicates this would indeed be the Chinese satellite WHG-01.

PAN is moving back westwards again

 

click diagram to enlarge

In September 2021 I wrote a blogpost noting that the enigmatic geosynchronous SIGINT satellite PAN/NEMESIS I (2009-047A) had left 47.7 E and was drifting eastwards. By 30 August 2022 it had drifted as far as 63.1 E.

But somewhere in September 2022, it reversed its drift and started to move Westwards again. Greg Roberts in South Africa recovered it on 30 September 2022 at 55.7 E after he looked for it in vain at more eastward positions.

From tracking data over the period May 2021 - August 2022, PAN was drifting eastwards at a rate of about 0.27 degrees/day. The drift started late February 2021.

It subsequently must have rapidly moved West again, by at least 0.23 degrees/day. It is not clear yet whether the drift continues, or if it is now stable at 55.7 E. Future observations will tell.

At the time of the eastward drift, I was not sure whether the drift was deliberate or the result of an operational "end-of-life". With the halt of the drift and subsequent rapid move westwards this month, it seems to me that the drift was deliberate and the satellite is still operational.

PAN/NEMESIS I was launched in 2009 and is a SIGINT satellite with a very unusual role. As the diagram in top of this post shows, it frequently relocated between late 2009 and late 2013 (which was very unusual), stalking a number of commercial communications satellites and eavesdropping on them. By 2014, this behaviour suddenly stopped, and for a long time it was kept at a stable position near 47.7 E, untill it started to drift in February 2021.

Six years ago I wrote an in-depth article on this enigmatic satellite for The Space Review that you can read here.

PAN/NEMESIS 1 is still drifting

 

click image to enlarge

In a blog post in September, I wrote that after almost eight years of being steady at longitude 47.7 E, the classified  SIGINT satellite PAN/NEMESIS 1 (2009-047A) had started to slowly drift eastwards, with the drift starting in February 2021.

Observations on the evening of November 8 show that it is still drifting. Currently it is near longitude 54.8 E, close to Yamal 402 and the grouplet GSAT 8, GSAT16 and GSAT 29, as is visible in the image above.

As it is drifting eastwards, it is getting lower in my sky: currently it is at 14.7 degrees elevation above my northeastern horizon.

The history of PAN's relocations so far (for backgrouds on PAN, its probable role and its frequent relocations during the first five years of its life, see my 2016 article in The Space Review):

click diagram to enlarge

PAN (NEMESIS 1) is on the move again

Pan on August 8/9, 2021, imaged from Leiden. Click image to enlarge

Five years ago, in 2016, I wrote a long article in The Space Review titled "A NEMESIS in the sky: PAN, Mentor 4 and close encounters of the SIGINT kind". The primary subjects of that article were two SIGINT satellites: PAN (Nemesis 1) and Mentor 4.

In the article, I discussed what we had observed and deduced about PAN as amateur trackers, to what had been recently revealed about PAN by leaked documents from the Snowden files.

In the article I documented the frequent movements of PAN (2009-047A): for four years between its launch in September 2009 and mid 2013, PAN, very unusual for a geosynchronous satellite, was roving from location to location, each time being put close to a satellite for commercial satellite telephony.
For information on the "why" of that, and the larger context of it (a new kind of SIGINT information gathering), I refer to the earlier mentioned Space Review paper which goes into details.

Mid-2013, four years after launch, the frequent relocations stopped. For 8 years, the position of PAN remained stable in longitude near 47^o.7 E. It's roving days, snooping around and sniffing other satellites, were over. Until this year.  

Somewhere between 6 February and 7 May 2021, PAN started to move again, eastwards in longitude. Observed longitudes over the period May-August 2021 suggest a drift eastwards at about 0.025 deg/day. 

Assuming a stable drift, the move appears to have been initiated within a few days of 11 February, 2021.The last observation still showing PAN at 47.7 E was on 6 February 2021 (as it happens, our network did not observe it again untill early May 2021 when it had already moved eastwards by two degrees).

The diagram below (an updated version of one that appeared in my 2016 Space Review article) shows the positions in longitude that PAN has been taking up since its launch in 2006. Note the frequent relocations over the period 2009-2013, then the long stabilization at 47.7E, and the start of a new drift episode in 2021:

click diagram to enlarge

The question now is, what this drift since February means:

(1) Has it deliberately been brought into a drift state to move it to an eventual new position? 

(2) Has it reached end-of-life and been manoeuvered into a graveyard orbit?

A 'graveyard orbit' is usually an orbit that is located at least 235 km higher than a geosynchronous orbit. That does not appear to be the case here: if anything, the orbit seems to be a few km lower than it previously was. So it appears to be option (1).

It will be interesting to see whether PAN will stabilize its longitude at some point or not, and where that will be. Unfortunately, as it is drifting eastwards it is getting lower in my sky (currently, it is some 16 degrees above my local horizon), and there do not appear to be many other amateurs covering it currently.

It would be interesting to see whether radio observers can detect radio signals from PAN, which shortly after launch was emitting at frequencies similar to that of the "UFO" (UHF Follow On) constellation.

PAN on 2/3 June, 2021, imaged from Schiermonnikoog Island. Click to enlarge