Frequencies - there was nothing to stop us registering the same frequency assignments, once the system had closed due to bankruptcy We did not need to buy the system to get them. And in any case there are still frequencoes available for our own system if we needed them.
Currently handled by the FCC in the USA, but the ultimate controller is the ITU. Orbits means frequencies - no allocation then your satellite can’t communicate with anyone. (Which is why there is such an interest in laser comms between constellation elements*).
https://www.itu.int/en/mediacentre/Pages/2019-PR23.aspx
https://www.itu.int/en/mediacentre/b...e-systems.aspx
https://arstechnica.com/tech-policy/...nd-satellites/
http://satellitemarkets.com/news-ana...constellations
* https://www.nasa.gov/directorates/sp...ared_crosslink