KRAKsat Satellite

@KD9KCK - please, have a look here:
After a restart, KRAKsat is simply transmitting “START U1, START U2, BOOT NR x” and after these messages there should be a beacon (as described in pdf).

Best regards,


As far as I can tell from the frames stored in our DB: not a single beacon has been recorded since. But it reboots a lot! ~500 reboots in ~4h45min, see:

        "time": "2019-08-04 05:47:34",
            "monitor": ":SP6ZWR:        BOOT NR 10561"
        "time": "2019-08-04 01:00:33",
            "monitor": ":SP6ZWR:        BOOT NR 10069"

Unfortunately we do not have any telemetry yet :frowning:

Definitely in a boot loop. Observation 905768: KrakSat (44427)

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Hello Alicja,

As KrakSat seems to get more healthy after a while there are some undocumented beacon contents present in the recorded data. Could you give some more hints on, e.g. ER, CU, EM, etc.?

Best regards,

Hello Patrick,

Yes, we know that unfortunately KRAKsat is now in the boot loop.
Where did you find these beacons? EM, CU and ER are Światowid’s (ID:44426) beacon parameters.

Best regards!

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Ok, so they might have overlapped in an observation. Just wondering: is that still possible?

We have a very basic dashboard, only showing the ASCII strings of the telemetry beacons, at

No filtering, so it might indeed be beacons from other satellites that crossed the KrakSat observation. But there also seem to be some data from KrakSat besides the boot-loop counter…

Maybe they have overlapped, maybe it’s still possible… After the restart there actually should be a beacon from KRAKsat, but as far as I know it manages only to send first line of it (STS with 32-bit 0/1 status) and after that it starts to reboot again. If you encounter a log from KRAKsat with master or radio status (M1;LOG or U1;RL), please let us know - it would be very valuable.

Thank you for your interest and help!

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Sure, I’ll check that immediately!

Everything we have containing M1;LOG or U1;RL unfortunately is from SR6SAT - Swiatowid :frowning:

Ohh, as I expected… But thank you very much for checking.

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I think it would be best if they could shut KRAKsat down for a while. Let it fully charge its batteries (Assuming thats why its dropping out half way thru boots)

Going to also assume thats not possible because of it failing to boot.

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@KD9KCK - as you assumed, it’s unfortunately not possible.

Dear all - I’m today here with another petition. If there was a possibility that anyone could try to listen to KRAKsat when it’s in sunlight, it’d be absolutely amazing. Since 11.09 every recording is from the night (and at night it probably doesn’t reboot) and timings of passes above our GS are also at night - so we don’t really have any information if it’s still “working” or not. It’d be very valuable and any help it’s much appreciated. If you have any questions, don’t hesitate to ask.

Thank you!

Could you calculate and give us the time periods that KRAKsat is in sunlight?

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It’s in sunlight on the Southern hemisphere. I already scheduled a few passes on some Australian stations.

We need a tick box on the scheduling interface that will only schedule passes in sunlight or night time. The ephem library provides a function to tell whether a satellite is sunlit or not.


Thank you very much for your help! It seems that it’s still restarting (reboot nr 106313 today).

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Created an issue to track this enhancement: satnogs-network#675


I scheduled a few observations on my Ground Station 160km South of Sydney.
Some of the heard AFSK signals were very strong but it sounds like it is still in
some sort of endless loop.
Wolfgang vk2byf


Yes, you’re right - but it’s good to know that it’s not completely silent after all. Thank you very much for your support!

Hi all!

Our simulations show that KRAKsat will be in sunlight all the time between 14 Dec 2019 03:35 UTC and 19 Dec 2019 07:31 UTC. It would be extremely helpful if anyone could listen to our satellite in that time, mostly on 14th and 15th of December (Saturday & Sunday) - we are going to need as many observations as possible to find out if change in lightning conditions changes the behaviour of KRAKsat and if we can do something about it (it’s still in reboot loop for now - more than 300 000 reboots achieved).

If you would like to know our satellite story more, we published a report today called KRAKsat Lessons Learned - it’s a summary and analysis of mistakes made during our satellite mission (both from payload and platform side). You can find it on ResearchGate (in english) here:

Thank you very much in advance.