The 2nd edition of "Spacecraft Mission Design" takes a short route to practical understanding of mission design. It focuses on the most general and most practical tools needed for the early spacecraft design studies, including the principles of two-body motion, definition of orbits, orbital manoeuvres and central body observation. The use of elementary mathematics makes this concise book ideal for college upperclassmen, graduates and practising engineers or managers. There are enough worked examples that one can be self-taught. This 2nd edition includes astronomical reference material, sections on constellations, lunar trajectories, and cycler orbits. In addition, the ORBWIN AIAA Mission Design software has been totally rewritten to make it easier to use and compatible with Windows. ORBWIN allows you to proceed directly from understanding into professional work. It provides the accuracy, speed and convenience of personal computing. It defines orbital elements for any orbit, provides the parameters at any orbital point, calculates spacecraft horizon, instrument field of view, orbit perturbations, ground track, planetary ephemeris, conversion of Julian days, oblique triangle solutions, and propellant weight projections.