An Introduction to Mission Design for Geostationary Satellites

Abstract

This text first saw life as a training document for mission analysts within the Dynamics Department of British Aerospace's Space and Communications Division. The intention was to make available in an easily understandable form, to newcomers to the field, the techniques and experience accumulated through years of mission design for a wide variety of spacecraft. It soon proved its worth, and not only with prospective mission analysts. Systems engineers, and others generally interested in geostationary spacecraft found it to be of value. It was clear that the text satisfied a need that could not otherwise be filled. There are many, and very good, books on celestial mechanics, there are many excellent books on astrodynamics, but until now there has been no book that explains the ins and outs of mission design, explains why things are done the way they are, as well as how they are done. For the much wider audience for which this book is designed, much of the material has been extensively revised, and portions have been completely re-written with the objective of providing a detailed and well-rounded account of the mission design of geosynchronous spacecraft. The work will be of interest not only to practising mission analysts, but also to spacecraft systems engineers, spacecraft project managers and to those who wish to employ the unique attributes of geosynchronous spacecraft for useful purposes. A basic understanding of orbit mechanics is essential for a good understanding of the text, but even this may be dispensed with for an appreciation of the introductory sections of the various chapters. This book is complementary to works on celestial mechanics, astrodynamics etc, and not a substitute for them. Fundamental orbit mechanics concepts are, therefore, taken for granted, and only those developments are presented which have a particular application to geostationary spacecraft. For reasons of logical development and narrative flow, the various mission design activities are presented in the order in which the mission of a real spacecraft will unfold. This does not imply that the analyses are, or should be, carried out in this order in support of a spacecraft project. No such simple ordering is possible in a field as complex as this, and in any case, the emphasis and ordering of mission design activities are governed by the requirements of a particular spacecraft project. After an introductory chapter, setting the scene and presenting a profile of the mission of a geostationary spacecraft, Chapters 2 to 6 take the spacecraft from launch through to the end of its useful life in geostationary orbit. The remaining chapters address topics that arise in several mission phases without being specific to anyone. Throughout the text no distinction is made between the meaning of the words spacecraft and satellite, and they are used interchangeably, and the same applies to the words geostationary and geosynchronous. By deliberate policy, the text is left free of references. The final section of each chapter contains an annotated list of the most useful literature pertaining to the subject of that chapter. The author gratefully acknowledges British Aerospace for valuable assistance in the preparation of the camera-ready copy, and the European Space Agency (ESA) for permission to cite the ESA family of communications spacecraft as examples throughout the text. On a more personal note, the author is indebted to his wife, Meher, for proof-reading every page of the text and enhancing its readability, to Jacqui Dennis for the typing and page layout, and to Jim Wertz, the Chief Editor of this series, for his unflagging enthusiasm for this book, and his valuable suggestions for its improvement. If, in spite of all this help, errors remain, they are entirely the author's own responsibility.