Update TLE of Celesta?

It seems from various tweets (@csumontpellier, @TSKelso) that 18 SDS has lost Celesta. The latest TLE is from July 28.

Can we use strf / SatNogs observations to refine the existing TLE of Celesta?

If useful, we could look a bit more with Dwingeloo, so that at least the signal to noise is not the limiting factor.

For observations of 28 August (6394890 and 6394891) I found 3kHz drift in 24 minutes from the artifacts. Files are attached.
celesta-6394890.csv (700 Bytes)
celesta-6394891.csv (595 Bytes)

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During the observations of 21 August, we got only 1 kHz drift in 24 minutes of observating (6365642 and 6365643). Strf files attached:
celesta-6365642.csv (560 Bytes)
celesta-6365643.csv (525 Bytes)

For reference, here are some observations from 29 August (not taken with SatNOGS), in strf format.
celesta-29aug.csv (204 Bytes)


Here’s an update TLE fitted to all observations.

1 53111U          22241.00000000  .00000000  00000-0  00000-0 0    05
2 53111  70.1517  84.1708 0015653 213.1670 334.3169  6.42041223    05
# 20220821.32-20220829.60, 74 measurements, 0.091 kHz rms

In the mean time, a new TLE has become available.


Indeed space-track.org has published it. Maybe our contact with them helped to solve the issue.

The TLE from Celestrak looks to be from something else. So Cees’ TLE above is probably the best for now.

Thanks for noting that! I’ve propagated the TLE by @cgbsat above and used it in DB and Network. Whoever had scheduled observations needs to re-schedule as the difference is signigicant!

The TLE in DB:

1 53111U          22255.00000100  .00000000  00000-0  00000-0 0    01
2 53111  70.1517  79.3185 0015497 209.1946 294.1392  6.42041170    09

I’m sorry, I’ve propagated the TLE set the wrong way, so the TLE set wasn’t available in Network for scheduling. I’ve just fixed it and now Network uses the @cgbsat TLE set.

A new Celesta TLE has been published on space-track.org. It is quite a bit different from the TLE that I fitted earlier.

A comparison against the Dwingeloo Telescope observations shows that the new TLE from space-track.org does not fit. So either the Dwingeloo Telescope observed a different object (unlikely because of decodes), or space-track.org is tracking the wrong object.


We tracked the space-track TLE yesterday with the Dwingeloo telescope, and (not surprisingly) saw nothing (6467318). We also tracked the TLE @cgbsat fitted (as propagated by @fredy), and saw nothing there either (6468538). As a final try, we also tracked the original TLE from June, and saw nothing there (6468587). So it could well be that the satellite has stopped transmitting.

It was mentioned on Twitter that the satellite may be dead: https://twitter.com/enzobecamel/status/1569723736042913794