Last 2 weeks of KRAKsat

[yiea]

Hi!

Short introduction

You might remember KRAKsat, our always-rebooting space cube . It was launched in April 2019 with Antares to ISS from which it was deployed (together with Światowid on 3rd July 2019). In short: it didn’t work at all at first, then it was operational for 2 weeks but because of other errors we were unable to perform the mission objectives, and finally it became stuck in the reboot loop in which it stays till now.

As the ISS orbit is sometimes synchronized with sun, putting the satellite in constant sunlight for even a few days a year (about what I wrote e.g. here: Satellite's orbits - a practical overview | alicja • space), when first situation like this took place, we tried to “save” it or, at least, download any data that could be not corrupted. It turned out that rescue cannot be accomplished but we managed to confirm that there is no correct data stored in the satellite’s memory - at least I could (with sadness) accept the mission as unsuccessful.

Thank you, SatNOGS

SatNOGS community was extremely helpful at all times. First, when KRAKsat was silent, your observations allowed us to confirm that it’s not transmitting all over the world, and what’s even more important - I found the first transmitted beacon on SatNOGS! Without your help, it could take even several hours or few days more to just discover that it is, in fact, working, so we are extremely thankful for that!

In December 2019, when all-sunlight period took place, I wrote a post here with request about scheduling observations (KRAKsat Satellite - #32 by yiea) during the rescue mission. And once again - you didn’t disappoint us, scheduling so many observations that (besides trying to perform communication sessions), we spend all days and nights going through pages of waterfalls. It was simply amazing. I am in endless debt to you.

Last two weeks in orbit

KRAKsat is now around ~280 km above Earth. It will took it probably around 2 weeks to completely burn in the atmosphere (I’m comparing with Światowid, which deorbited in March this year, and was launched in the same time).

If you want, it is the last chance to listen to it and see what will the final reboot number be . It is not critical this time, only out of curiosity - if you want to schedule some observations for the next 2 weeks, you are welcomed to do so.

To be honest I still cannot believe that this space adventure is coming to an end.

Once again - thank you all for participating, it was a great pleasure . I’m working on another satellite now (Intuition-1) which is a commercial project in the company I work for (KP Labs) - but we are also providing on-board computer for another polish student CubeSat - PW-Sat3 . So I hope that one day, we will listen for it, together!

If you want to read more about KRAKsat failure, here are two links to publications:

• (PDF) KRAKsat Satellite Mission - Lessons Learned [EN]
• (PDF) Analysis of Methods for CubeSat Mission Design Based on in-orbit Results of KRAKsat Mission

And you can find amazing SatNOGS dashboard here: Grafana

Thank you in advance for listening and have a great new year!

[yiea]

Hi,
KRAKsat is somewhere very low, probably around 200 km now. As there was no TLE update today, some observations are not really the best (e.g. SatNOGS Network - Observation 5306921).

It means, probably, that it’s going to reenter - today, tommorrow, day after tommorrow - very soon. According to prediction (https://twitter.com/jremis/status/1482280192596922370), it could be the 18th of January (but I have a feeling that it can be even earlier).

If you want to listen it for the last time, it’s your chance. Thank you once again in the name of KRAKsat team and our always-rebooting cube.

I’ll write here after the confirmed reentry.

[kerel]

Based on the latest observations of Kraksat in SatNOGS (5304653, 5306922, 5307948, 5310032) I manually fitted a TLE.

1 44427U          22014.99962613  .00000000  00000-0  98586-3 0    07
2 44427  51.6301 286.4795 0008988 186.6244 260.4415 16.21043104    08
# 20220116.66-20220116.78, 78 measurements, 0.239 kHz rms

Validation with ikhnos against a previous observation:

Thank you Alicja for letting us take part in the journey of KRAKsat by this write-up up until re-entry!

edit: accidentally posted the unfinished post…

[fredy]

The TLE set is added in DB. If you have scheduled observations of KRAKsat please re-schedule.

[sp6hfe]

Hi Alicja @yiea,

I’ve read lessons learned from the mission you’ve linked above and I am impressed by the amount of the things you’ve (the team) detected that in the effect lead the mission to fail.

It is encouraging to see people learning new things the hard way, iteratively, based on gained experience, but that’s the way it goes oftentimes!

In my opinion, despite costs generated and maybe unfulfilled agreements, there is a benefit out of that mission: the next one will be pretty much different and the team performing it should be filled with people working on the KRAKsat project.

In the document, it was mentioned that consultancy with people from space business is vital. Remember you’ve (the team) just learned a piece of know-how enabling you to be successful in the next projects, allowing you, at the same time, to guide and inspire others that are just starting!

Good job!

[yiea]

Amazing, thank you @kerel - now it’s perfectly decodable
Unfortunately, it seems that they forgot about KRAKsat, because there is still no new “official” TLE…

@sp6hfe - Thank you for the kind words! We tried to take from this failure as much as we could.

[yiea]

KRAKsat is falling down like crazy and I see that unfortunately the TLE from @kerel is starting to drift too…

I asked my friend Tomek to compute a new TLE - here is the result:

1 44427U          22017.50000000  .00000000  00000-0  99927-3 0    00
2 44427  51.6301 286.4795 0008988 186.6244 151.9370 16.36313808    09
# 20220117.51-20220117.70, 69 measurements, 1.576 kHz rms

We’re not 100% sure if it’s good but if you could have a look, and if yes - add it to the DB, it would be amazing @fredy

[kerel]

Awesome, I’ll cross-check! Over at https://matrix.to/#/#satnogs:matrix.org we were also discussing a new TLE I created for Kraksat, but it didn’t fit as well as the one yesterday.

I also started to publish the underlying doppler data at Fabian P. Schmidt / SatNOGS Doppler Observations · GitLab

Let’s see how long we can see KRAKsat!

[fredy]

Bellow are the results on the latest good observation of the two TLE sets:

@kerel’s

1 44427U          22016.00000000  .00000000  00000-0  98586-3 0    04
2 44427  51.6301 280.9564 0006183 186.3817 326.7374 16.28484697    02

And from the TLE above:

So, It seems the one that @kerel generated follow better the curve… I’ve chosen that set to use in DB, Let’s see if we get anything. @yiea thanks anyway for sharing the TLE set.

[yiea]

Thank you for the verification!

[w6msu]

https://network.satnogs.org/observations/5318507/
Rather thin evidence (HI). It was at TCA.

73,

[yiea]

Last sucessful observation is from yesterday ~18 UTC (SatNOGS Network - Observation 5311486). After that I have a confirmation that is was silent above Japan around 3 UTC (their daytime) - https://twitter.com/JA0CAW/status/1483280118663770114 and a lot of blank observations from SatNOGS.

There are many also observations planned for today, and I’m also waiting for passes to be above Europe - if there won’t be any sign of restarts until my evening (CET timezone), I’ll confirm officially (and sadly) that KRAKsat has burned.

[yiea]

Okay, it looks like KRAKsat has ended its mission.

Thank you - all of you - for your neverending support, willingness to help and all the observations. Best community of radioamateurs in the world.

I published official info on KRAKsat twitter account: https://twitter.com/kraksatpl/status/1483537279184420865