This book describes the reliability research results and experience of BeiDou navigation satellite in engineering development. According to the characteristics of high reliability and high availability, this book discusses the reliability requirements, reliability design, reliability modeling, and reliability analysis of navigation satellite and constellation, focusing on the demonstration and decomposition of reliability requirements, constellation availability design, satellite availability design, and availability analysis. Based on the characteristics of batch production of navigation satellites, the particularity of reliability work is analyzed, and the batch production reliability assurance works such as process reliability, data consistency comparison, storage reliability, and satellite redundancy demonstration are introduced. This book is suitable for engineering developers of aerospace product manufacturers and postgraduates majoring in spacecraft engineering and reliability.