Preface

A space orbit refers to the route along which a celestial body travels in space. It can also be called a trajectory or an orbit for short. Generally, there are three types, namely, launch orbit, operational orbit, and re-entry orbit. It follows that space orbit theory is about the principles and methods that the design of a space orbit should comply with, while orbit design is one of the key technologies in spacecraft system design. Orbit design needs to take many factors into consideration, such as orbit dynamics, space environment, mission requirement, and capability of effective payload, among others. Theories regarding orbit design were proposed long before the first man-made satellite was launched into space. With the growing demands in space application and the advancements in space technology, classical orbit theories and design methods can no longer meet the requirements of new space missions. There is an urgent need for new space orbit theories which can effectively bring advanced space technology into full play. On the basis of decade-long research findings, this book aims to answer the call of these new developments. There are eight chapters in this book. The first part consists of the first two chapters, which are a general review of recursive orbit, synchronous orbit, frozen orbit, stay orbit, and other classical orbits, together with their design methods. Based on this review, the focus of this book, i.e., concepts, types, and applications of special space orbits are introduced. The second part is from chapter three to chapter eight. Each chapter is about a specific orbit, together with its concepts, characteristics, design methods, and applications. So altogether, there are six special space orbits which are elaborated, namely, hovering orbit, spiral cruising orbit, multi-target rendezvous orbit, initiative approaching orbit, responsive orbit, and earth pole-sitter orbit. This book is based on the findings of our research team over the years. We want to thank Profs. Zhi Li and Lei Wang, postgraduate students Xiaojing Xu, Yuanfei Li, and Haijun Zhou, for their contributions to this book. Theories of space orbit design are closely related to other fast-changing areas of study and develop along with new space applications. The authors are fully aware