In this scheme they would be controlled by a central party, as effectively we're talking about Starlink and SpaceX. Or maybe one of the legacy satellite interne

In this scheme they would be controlled by a central party, as effectively we're talking about Starlink and SpaceX. Or maybe one of the legacy satellite internet providers. Assuming that though, you send a hash of your content up to the system, which geolocates it (based on physical reception), adds a timestamp and geolocation into the metadata, and returns the signed information, using the central party's key. You also could run a similar method on cellular networks by using towers as the signing node and the telecom as the centralized entity. Because realistically, it's not Byzantine Generals. What you want is (a) timestamp verified by a trusted party, (b) geolocation verified by a trusted party, (c) content hashed/signed to prevent subsequent modification, (d) prevention of replay forging of (a) or (b), & (e) most of the infrastructure not physically accessible by users (e.g. signing chip embedded in a camera).