Mobile-Satellite Service. A radiocommunication service:
(1) Between mobile earth stations and one or more space stations, or between space stations used by this service; or
(2) Between mobile earth stations by means of one or more space stations.
47 CFR § 2.1
Where a term or definition appears in this part of the Commission's Rules, it shall be the definitive term or definition and shall prevail throughout the Commission's Rules.