This paper describes a complex hybrid terrestrial-satellite mobile network which includes both Satellite Based Network (SBN) and Ancillary Terrestrial Component (ATC) components that are integrated via a single logical standards-based core network based on 3GPP and 3GPP2 network entities. Next generation session controls are implemented across its all-IP core and transport network via an IMS Core utilizing SIP signaling. Two satellite air-interfaces, GMR1-3G and satellite BRPD (sHRPD), operating over a GEO satellite are described and their main and advanced features and performance are reviewed.