Spacecraft Dynamics and Control: A Practical Engineering Approach

This addition to the spacecraft dynamics and control literature joins a fairly short list of texts that treat control of both orbit and attitude dynamics, including Bryson’s Control of Spacecraft and Aircraft (1994), Kaplan’s Modern Spacecraft Dynamics and Control (1976), and Wiesel’s Space ight Dynamics (1996). As the subtitle indicates, a novel aspect of this text is its emphasis on the “practical engineering” details of the subject, and the book succeeds in its stated goal of introducing “the basic engineering notions of controlling a satellite.” The author’s experience in the Želd is clearly demonstrated through his extensive use of examples illustrating the fundamental concepts; in fact, the cover features an image of one of the author’s projects—the Amos 1 satellite. The essence of the book is the development and linearization of the appropriate equations of motion, followed by the solution of typical automatic control problems using the basic tools of linear control theory. The author assumes that his readers are familiar with these tools, so that Bode plots, Nichols charts, and so forth are used with minimal explanation. Although the author uses some matrix and vector notation throughout the text, many equations that could be expressed succinctly in vector notation are given in scalar notation. Although this may make the book more readable for some, the use of scalar notation obscures some of the advantages that come with the use of state-space methods. The book has 10 chapters and three appendices. The Žrst chapter introduces the subject matter with a brief look at the life of a spacecraft from the dynamics and control analyst’s viewpoint and provides an overview of the rest of the text. There are two chapters on Orbit Dynamics and Orbital Maneuvers. Most of the usual topics are included; however, there are notable exceptions. The time-of-ight problem and the design of interplanetary missions using patched conics are both absent. The latter omission is especially noteworthy because many students want to do projects in this area and the AIAAsponsored student design competitions typically involve interplanetary mission design. On the other hand, this is the only book I have seen that emphasizes the importance of attitude control during orbit transfers. The remaining seven chapters cover a variety of key topics in attitude dynamics and control. The Žrst of these develops the basic equations of motion for a rigid body, including kinematics in terms of both Euler angles and quaternions. Part of the kinematics analysis is removed to an appendix, which should not trouble a careful reader. Two things about the development are troublesome. The Žrst involves a lack of rigor that will not impede the practical application of the equations of motion. Namely, the development of angular momentum passes directly from a summation over a Žnite number of mass particles to an integral over a continuum without any mention of whether this is an appropriate move. (For the interested reader, Truesdell’s essay, “Whence the Law of Moment of Momentum?” in his 1968 Essays in the History of Mechanics is recommended.) The second item also involves moments of inertia. The author claims that the “engineer generally prefers a satellite in which there are negligible products of inertia.” Whereas the experienced reader will understand the meaning here, newcomers to the subject may get the mistaken idea that products of inertia are satellite properties rather than reference frame properties. The second of the attitude dynamics and control chapters treats Gravity Gradient Stabilization. This chapter begins with an introduction to all of the subsequent chapters and deŽnes “the basic attitude control equation” based on a linear PID (proportional-plus-integralplus-derivative) control law whose gains are to be developed as appropriate for each problem. The discussion of gravity gradient stability is thorough and includes examples with passive, active, and magnetic damping. The discussion of the DeBra–Delp region is misleading in its statement that the region “is seldom used owing to practical structural difŽculties.” The fact is that this region is unstable in the presence of damping (see, for example, Sec. 9.3 of Hughes’ 1986 Spacecraft Attitude Dynamics). The remaining chapters cover Spin and Dual-Spin Stabilization, Attitude Maneuvers in Space, MomentumBias Attitude Stabilization, Reaction Thruster Attitude Control, and Structural Dynamics and Liquid Sloshing. All of these chapters are unusually thorough in the sense of providing useful information on the effects of real-world difŽculties such as sensor noise and actuator limitations. The chapter on attitude maneuvers includes excellent coverage of the use of momentum wheels as momentum exchange devices for maneuvers; control moment gyros are not covered. The author restricts attention to control synthesis based on linear dynamics models and for largeangle rotational maneuver refers readers to Junkins and Turner’s 1986 textbookOptimal Spacecraft Rotational Maneuvers, which remains the only textbook treatment of this topic. One especially useful feature of the book is the extensive use of speciŽc examples illustrating the various topics. Although some of these examples do not include all of the data necessary to reproduce the results exactly,