**Abstract**

From the first satellite launched in 1957, these systems always have drawn the attention of telecommunications operators. Thanks to their natural orbit, satellites can provide coverage to the entire globe or serve a vast region. Is this feature that makes them potential systems to extend current ground networks over the space. The first satellites were conceived as a single backhaul system to broadcast television or phone calls. Over the years, this concept evolved to a group of satellites that compose a constellation to interconnect any user around the globe. Nowadays, these constellations are still evolving to massive architectures with thousands of satellites that are interconnected between them composing satellite networks. Additionally, with the emergence of 5G, the community has started to discuss how to integrate satellites in this infrastructure. A review of the evolution of the satellites for broadband communications is presented in this chapter, discussing the novel and future proposed architectures. The presented work concludes with the potential of these satellite systems to compose a hybrid and heterogeneous architecture in which space, air, and ground networks become interconnected.

**Keywords:** Satellite networks, Non-Terrestrial Networks, Satellite communications, Internet of Satellites, Mega-constellations
