**1. Introduction**

Since 1957 with the launch of the first artificial satellite *Sputnik 1*, space has been populated by a wide variety of satellite systems. The development of new technologies proliferated the emergence of different satellite platforms for multiple purposes. The global miniaturization of the technology influenced the satellite design by enabling small satellites with reduced mass. This trend not only drove the satellite shape, but also noteworthy impacted on the perception of a satellite, and its development.

This has been reflected also in satellites developed to provide broadband telecommunications services. The global coverage and large spot areas are features that naturally characterize satellites, and which telecommunications operators may leverage to deploy services. Therefore, the first satellite to provide television broadcast was launched in 1964 [1]. New missions and systems followed this launch, achieving better communications performance from space, and certifying that satellites may

become a crucial system in these services [2, 3]. The achieved results encouraged to go a step forward on the design of satellite constellations. These constellations are composed of a group of satellites that work for the same goals. In this case, these constellations were conceived to provide phone services in low-orbit regions. Iridium or Globalstar are examples of the viability of the system [4, 5].

These constellations enabled to think about systems in which satellites are interconnected with Inter-Satellite Links (ISL) to exchange data [6]. These new systems represent satellite networks that dynamically change their behavior over time. With this new concept, novel architectures to optimize this dynamic behavior were presented [7–10]. From the proper definition of a single network to the integration of different constellations, each of those proposals presented unique features to enhance satellite services.

The apparition of the New Space concept and all the associated technology development also drove the novel progress in the broadband telecommunications domain [11]. In particular, the apparition of the mega-constellations became an important disruption in the concept of traditional constellations [12–14]. This architecture proposes the deployment of thousands of satellites to provide global Internet coverage. Among the different technology challenges, this approach also triggered the discussion of other difficulties related to frequency allocation or satellite manufacture procedure [15, 16]. An alternative to these massive constellations proposed the collaboration between satellites to share unused downlink opportunities. The Internet of Satellites (IoSat) paradigm [17] proposes the establishment of temporal satellite networks according to the necessity to exchange data. This dynamic environment poses new communications challenges that must be addressed in future researches.

The fifth-generation technology standard for cellular networks (5G) has been already established on the ground infrastructure as a fast, reliable, and highconnectivity communications interface for cellphones and other devices. Nevertheless, current discussions are still been performed on how to integrate satellite systems in this infrastructure [18]. Thanks to its global coverage, satellites become potential systems to expand current ground networks with a Non-Terrestrial Network (NTN) [19]. This network leverages this high altitude architecture which awards the satellites with unique qualities for the 5G. The large coverage area of spaceborne telecommunications systems enhances the service continuity in case that is not being ensured by ground infrastructure. Furthermore, satellite coverage enhances the network capacity by serving a myriad of end-users with a single spot. Finally, the orbit trajectory of a satellite allows reaching the service ubiquity on the entire globe, being able to provide services in remote and typically inaccessible areas.

This chapter surveys the evolution of satellites for broadband telecommunications services that have been experienced in the last years. Details of each developed technology are presented and discussed the implications on current and future network infrastructure. The remainder of the chapter is structured as follows. First, the apparition of broadband telecommunications satellites is presented in Section 2. Section 3 presents the satellite constellations that provided novel broadband services. The concept of satellite networks is discussed in Section 4. The impact of the New Space trend is presented in Section 5. Section 6 presents the novel concept of IoSat, while Section 7 discusses the integration of satellites in the 5G infrastructure. Finally, Section 8 concludes the chapter.
