Space communications between distant spacecraft and the Earth are mainly based on large reflector antennas, such as the 35-m Deep-Space Antennas of the European Space Agency. These provide the required G T and EIRP to existing missions, such as, for example, Rosetta, Mars Express, and Venus Express. However, future missions to Mars and to outer planets (Jupiter and Saturn) are going to require higher performance for the ground segment that current stations cannot offer. This paper presents the results carried out in the framework of a strategic feasibility study promoted by the European Space Agency to identify the best architecture for future deep-space ground stations. Technical, economic, and operating aspects are described, deriving high-level specifications for future ground stations, and discussing in detail the antenna options and the subsystem devices. As an outcome, two different ground-station architectures, based on arrays of reflector antennas, are proposed and discussed in detail. These indicate the roadmaps that are going to pave the road to the final implementation.