This book, one in the series on Aerospace Education III, includes a discussion of the essentials of propulsion, control, and guidance and the conditions of space travel. Chapter 1 provides a brief account of basic laws of celestial mechanics. Chapters 2, 3, and 4 are devoted to the chemical principles of propulsion. Included are the basics of thrust, the differences between solid and liquid propellant engines, devices for generating electrical power in space, the potentialities of nuclear and electric rockets and thrust and thrust-vector controls. Chapter 5 is entitled "Control and Guidance Systems" and deals with topics such as servomechanisms and computers, types of guidance systems, and position fixing or celestial navigation. The final chapter includes a discussion of suborbital, earth orbital, lunar, and interplanetary flight. The book is designed for the Air Force Junior ROTC program. (PS)