• The authors have more than 54 years of practical real- world experience and attempt to encompass this experience

in the chapters and suggested problems.

◦ Many of these problems have been adapted from these actual space projects and can not be found in many contemporary text books.

• This book will be used by practicing engineers and other texts may provide a deeper theoretical background.

◦ The reader can refer to more than 170 historical references beginning with Arthur C. Clarke’s 1945 reference describing his ideas for formation flying of three communication stations in a geosynchronous orbit in order to provide, through relay technology, instantaneous communication to/from any location on the Earth’s surface, and also to/from various orbiting spacecraft.

• The text begins with a review of orbital mechanics, emphasis here is placed on digital control techniques and specific application for formation flying, deployment, station keeping, and reconfiguration.

◦ Part of the formation flying is based on research contractors with the Applied Physics Laboratory, and DARPA, focusing on on-track (string of pearls) and 3-D tetrahedron configurations in highly elliptical orbits. The tetrahedron was suggested as of a design challenged by NASA Goddard.

• Advanced modern control techniques including intelligent control application such as fuzzy logic, hierarchical control, and adaptive control are proposed for the first time for formation flying applications.

◦ Some of these methods have been previously implemented for industrial applications, such as in the use of stepper motors.

• The philosophy is that most of us learn by practicing, which means by working problems of various degrees of difficulty. Suggested problems attempt to follow the material covered in the preceding chapter.

◦ Some of the suggested exercises came from the author’s own classes taken at MIT, the Catholic University of America, Howard University, various short courses at UCLA, and evening classes taken at the Applied Physics Laboratory and elsewhere. And many of the exercises were adapted from the authors’ practical experience.