This paper considers many of the factors and criteria which have to be considered and evaluated when selecting a specific rocket engine for a given vehicle application. The lists of criteria can be helpful as checklists in design and systems engineering of a rocket propulsion device. About ten different applications are examined to illustrate the relative importance of some of these selection criteria. There will be groupings of our major types of criteria; namely, performance, operational, economic and so-called judgment criteria. In many cases the last three categories are equally or more important than the performance criteria in selecting one of several rocket engines for a specific application. The actual selection usually is a compromise to make the rocket engine responsive to several important criteria.
