I think it must be mostly a spectrum/licensing concern:
Neither T-Mobile nor Starlink own global frequencies in a suitable frequency band to offer offshore services.
That's one of the big benefits e.g. Apple gets out of the box for going with Globalstar, and Qualcomm for partnering with Iridium: They each own around 10 MHz of prime (i.e. L-band) global spectrum.
There is no global spectrum ownership, most countries regard radio waves as a national resource. ITU and related bodies only manage the standards not the allocation or ownership to operators.
What Globalstar, Iridium et al have agreements are agreements with wide array of countries but not all, for example India only allows Innmersat based devices , North Korea allows no one and so on.
OST does not cover radio frequency, only outer space( which is not well defined) ownership and activities, while the Bogota declaration failed to make progress for the equatorial countries at the UN, there are no major dispute on who owns the spectrum in the space above their national territories, most agree it is a national resource. Also to note there are many countries who are not signatories and/or not ratified the OST mostly in Africa.
Thank you for this context! Radio spectrum being considered a national resource actually makes a lot of sense. It also explains why Starlink's (residential) geographic availability map looks the way it does (i.e. corresponding to political borders).
Do you know if this is different for e.g. aviation applications or international waters? I also wonder whether Starlink (and other non-GEO operators) actually stop transmitting over countries where they don't have a license for their spectrum.
Nevertheless: Practically, Inmarsat, Globalstar, and Iridium do hold exactly these crucial L-band spectrum rights in almost all countries; Starlink doesn't yet.
In aviation, ICAO the governing body splits the globe into Flight Information Regions ( sub classified into ACCs) and delegates the management will have national member be responsible over international waters here is a list https://en.wikipedia.org/wiki/Flight_information_region
The national ICAO will "manage" practically used part of VHF and HF(pilots would use High Frequency over the ocean for greater propagation) and probably few other parts of the spectrum in this region they of course do not own the spectrum in that region.
Starlink and other communication satellites indeed will not transceive in a country without a license. In their case they transceive and not just transpond (broadcast). If any base station is attempting to connect to the satellite in a forbidden country by definition that is illegal and they will not acknowledge or open the connection.
This is why SpaceX is does not allow operations in disputed regions like Crimea, they do not want to be in position of recognizing sovereignty of disputed land for either Ukraine or Russia.
Related note: companies also don't want their civilian tech used for military applications, reason why DJI doesn't want their drones sold to either Russia or Ukraine. If they start getting classified as dual use by countries, they will be subject to export controls, sanctions etc.
This is a fascinating take. Cell phone adoption could push SpaceX into establishing a global spectrum committee. Let's hope they remember to register under the .INT domain
Well, that global spectrum committee already exists [1], .int domain and all :)
But somebody recently mentioned here that in order to provide satellite services in a given country, you still need a local license...?
I'm not sure how existing mobile satellite service providers fit in here – do Inmarsat, Iridium etc. just have a license in (almost) all countries worldwide?
Not all but a lot. It is a mixed bag though, Iridium and Thuraya are illegal in India but Inmarsat has a license, so it kind of depends really.
You need a local license because radio frequency is considered a national resource, so each country owns the radio space about its land and they get to govern it.
That makes sense. So the ITU has more of a role of coordination than of actual assignment, I suppose?
Practically, satellites won't switch frequencies every time their spot beam footprints cross national boundaries, so I suppose it's more of a matter of allowing/not allowing service in a given country (as determined by either the mobile or the satellite?).
The other tool is simply not allowing receivers to sold or used to decode/decrypt forbidden sources in a country enforced with import ban like with satellite phones etc.
That's news to me! Does ITU have any ability to mandate laws for the physical spectrum? If not, a global communications committee would still be needed. At minimum, they would need the ability to control the 5G blocks of every country participating in the SAT to cell service.
Like most of these international committees, I believe they mostly facilitate agreements between sovereign states; I don't believe they have any legislative power themselves.
Maybe an analogy would be ICAO's (another "specialized agency of the UN") "Freedoms of the Air" [1] – they define the terminology, but it's still up to individual (or blocs of) nation states to actually grant them to each other, ratify recommendations etc.
Neither T-Mobile nor Starlink own global frequencies in a suitable frequency band to offer offshore services.
That's one of the big benefits e.g. Apple gets out of the box for going with Globalstar, and Qualcomm for partnering with Iridium: They each own around 10 MHz of prime (i.e. L-band) global spectrum.