It is nice to see another open source satellite [1]. Usually i only saw used in the satellites, releasing also the hardware part is super cool.
However there are also other notable repositories.
There is for instance a "space kit" for arduinos [2].
Another interesting project was QB50 [3], many student satellites, from multiple universities worked together to study the lower thermosphere. If you search for QB50, there are multiple public repositories with the code they used.<p>[1] - <a href="https://github.com/Quetzal-1-CubeSat-Team">https://github.com/Quetzal-1-CubeSat-Team</a>
[2] - <a href="https://github.com/ArduSat/ArdusatSDK">https://github.com/ArduSat/ArdusatSDK</a>
[3] - <a href="https://spaceflight101.com/spacecraft/qb50/" rel="nofollow noreferrer">https://spaceflight101.com/spacecraft/qb50/</a>