Driven by innovations in satellite technology and cell phone electronics, direct-to-device (“D2D”) services have emerged to enable direct communication between satellites and standard consumer devices, including smartphones and IoT sensors. D2D promises to make most future mobile handsets capable of communicating worldwide, albeit with potentially limited throughput, without needing to be in range of terrestrial base stations. Despite D2D's obvious utility, identifying appropriate spectrum is a significant challenge for new D2D services. Spectrum licenses are extremely valuable when used for terrestrial mobile broadband. Thus, mobile operators may be reluctant to set aside substantial amounts of unimpaired terrestrial spectrum for D2D use on a multi-region basis or even to allocate this spectrum in areas near cities so that D2D can be used to fill in coverage gaps. As a result, using terrestrial spectrum for D2D is likely to result in a patchwork of coverage, with restricted spectrum access, across a limited number of countries. Notably, existing Mobile Satellite Services (MSS) spectrum (as demonstrated by Globalstar’s partnership with Apple) provides nationwide (and potentially global) D2D coverage, covering all “dead zones,” whether they are near cities or in the most remote wilderness areas, whenever a terrestrial network is unavailable. 1 Nevertheless, access for new entrants to MSS spectrum is problematic due to active incumbent use in certain MSS allocations. Spectrum sharing has gained popularity in recent years in higher-frequency Fixed Satellite Services (FSS) bands such as the Ku- and Ka-bands, but it would be highly disruptive to existing MSS users.