ABSTRACT
This chapter gives an understanding of why rockets are needed and some mathematical tools that are the basics of trajectory and orbital mechanics. It provides the reason for rocket propulsion. The chapter discusses missions and payloads, which are the things one desire to accomplish and how one plan to accomplish them. Missiles typically deliver payloads on a ballistic trajectory. In order to truly understand what a rocket must do in order to deliver a payload, one looked into the details of trajectories and how to mathematically model them. The chapter discusses the Newton's laws of motion and universal gravitation and of Kepler's Laws. It also discusses orbital maneuvers and changes and how to calculate them. The chapter further discusses how to convert an elliptical orbit to a circular one and how to transfer from one orbit to another via some different approaches.
