decoding SpaceX telem with RTLSDR

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drew
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decoding SpaceX telem with RTLSDR

Postby drew » Thu Mar 25, 2021 2:39 pm

I don't know if y'all have been following but over on Twitter there's a whole slew of european RF nerds that are manually tracking SpaceX launches and recording the live telemetry video downlink stream in real time from the rocket. Honestly, I'm blown away by this. I've done a bit of ADS-B decoding as well as a bit of POCSAG (in minecraft) with my NooElec RTLSDR I bought years ago but I never expected one would be able to use that to record a rocket telemetry downlink.

Here's the site that has the most info in one place. Near the bottom is a 44MB decoded video they made from the data they captured.
https://www.r00t.cz/Sats/Falcon9

And here's an example setup consisting of a WiFi mesh antenna, MMDS convertor, and Airspy MINI SDR.

Image
Andrew Hamilton
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SpaceManMat
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Re: decoding SpaceX telem with RTLSDR

Postby SpaceManMat » Fri Mar 26, 2021 9:11 pm

Saw that, pretty cool stuff. I want to know if the transmit video for DOD launches, they do not stream the video once they stage these flights.
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ToniC
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Re: decoding SpaceX telem with RTLSDR

Postby ToniC » Fri Mar 26, 2021 11:48 pm

The first thing I thought of when I heard about this was if the data stream is cut or at least better encrypted for the higher security flights. If not, I'm sure that's about to change, if it doesn't break up the partnership.

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drew
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Re: decoding SpaceX telem with RTLSDR

Postby drew » Mon Mar 29, 2021 9:28 am

ToniC wrote:The first thing I thought of when I heard about this was if the data stream is cut or at least better encrypted for the higher security flights. If not, I'm sure that's about to change, if it doesn't break up the partnership.

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Yea, currently it's not encrypted at all, hence the easy decoding. Over the weekend a guy attempted to do the same with a Starship engine test but that transmission was encrypted.
https://twitter.com/r2x0t/status/1375472068595187722

Same with Electron, the downlink seems to be encrypted as well.
https://www.r00t.cz/Sats/Electron

I expect telemetry will continue and they will start encrypting the downlink on Falcon 9 flights.
Andrew Hamilton
AMRS 28 L3
AMRS Records Committee Chairman
Max Alt AGL - 26,850ft - L935 - THUNDA 2019
Max V - 3,004 ft/s, ~Mach 2.67 - L935 - THUNDA 2019

drew
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Re: decoding SpaceX telem with RTLSDR

Postby drew » Thu Apr 08, 2021 2:39 pm

AAAANNNNNDDDDD the party is over. Falcon 9 downlink is now encrypted. :cry:
Andrew Hamilton
AMRS 28 L3
AMRS Records Committee Chairman
Max Alt AGL - 26,850ft - L935 - THUNDA 2019
Max V - 3,004 ft/s, ~Mach 2.67 - L935 - THUNDA 2019


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