5G-IS; “5G system infrastructure study”, is a study funded under the ESA ARTES Strategic Programme Line “5G/6G and Sustainable Connectivity”. The study analyses and assesses different aspects of architecture design and related evaluation criteria, including key performance indicators, in order to identify potential system architecture options towards the deployment of a 5G space-based infrastructure (5GSBI – extending to beyond 5G and even 6G), complementing terrestrial next generation mobile networks. In a specific extension of the work, the focus of a dedicated deep dive was placed on 5G/6G satellite connectivity solutions for automotive/road transportation applications as one of the most promising market areas. Recent advances in space technologies (including new launch and propulsion concepts) have helped to significantly improve the performance and reduce the deployment cost of spacebased infrastructures. Collectively they have enabled a new generation of low earth orbiting satellites that allow to reduce round-trip air interface latency and make mega-constellations viable. The promise of service continuity, ubiquity and scalability that space-based assets can provide has drawn increased attention to the use of satellite communication technology as an inherent part of future communications infrastructures in the context of beyond 5G and 6G. 3GPP, the main standardisation body for 5G/6G mobile networks has recognised this development and made non-terrestrial networks (NTN) an integral part of its standards beginning with Release 17 and further expanding in scope and impact in the upcoming releases 18 and 19.