The ground segment is the fundamental backbone of every satellite project, yet it is usually not visible to the public or the end user of a satellite service. Also the bulk of existing published space literature tends to focus on the satellite or its subsystems. This book tries to fill this gap and addresses systems engineering concepts applied to the design, development, qualification, and deployment of the ground control segment required to operate a single satellite, a constellation, or even a manned space vehicle. The domain of ground segment engineering has significantly evolved in recent years, mainly driven by major advances in the IT sector. Hardware virtualisation or the availability of on-demand cloud computing services are typical examples of new technologies that have changed fundamental architectural concepts previously standard in heritage ground segments. Furthermore, the stark increase of cyber attacks - today a major risk to almost all critical IT based infrastructure - has made a cyber threat resilient architecture to become one of the indispensable design requirements for ground segment engineers. The new mega constellations recently put into space deploying up to several hundred of flying objects have put very demanding needs on the ground segment for automated satellite operations. These topics and more are addressed in the books chapters, along with a detailed explanation of the most relevant components of a typical ground segment architecture. The basic functional requirements, design features, and the most important ground and space segment interfaces are addressed and explained in detail, supported by a wealth of figures for easier understanding. This book is kept at an introductory level, allowing newcomers to get familiar with this fairly complex subject matter. It is therefore suitable for graduate students, but can equally serve as a valuable source of information for already experienced space engineers who seek to gain a deeper understanding of the ground segment infrastructure and related systems engineering processes. It can also help project managers to better interact with their systems engineers, satellite developers to define their ground segment interfaces, and satellite operators to improve their flight and ground procedures. It is very well suited for everyone intending to start a career in satellite ground segment systems engineering.