Drawing on practical engineering experience and latest achievements of space technology in China, this title investigates spacecraft system design and introduces several design methods based on the model development process. A well-established space engineering system with spacecraft as the core is integral to spaceflight activities and missions of entering, exploring, developing and utilizing outer space. This book expounds the key phases in the workflow of spacecraft development, including task analysis, overall plan design, external interface, configuration and assembly design and experimental verification. Subsystems that function as the nuclei of spacecraft design and important aspects in the model development process are then examined, such as orbit design, environmental influence factors, reliability design, dynamics analysis, etc. In addition, it also discusses the digital environment and methods to improve the efficiency of system design. The title will appeal to researchers, students, and especially professionals interested in spacecraft system design and space engineering.