English: Ever try to shoot a slow flying duck while standing rigidly on a fast rotating platform, and with a gun that uses bullets which curve 90° while in flight?" This question appeared in the July 1963 issue of Lab-Oratory, in an article about spacecraft trajectory design. During mission development in 1967, the trajectory design model shown above allowed Mariner Mars mission planners to illustrate the orientation of the planet, the expected path of the Mariner 6 and 7 spacecraft, and the window of opportunity for the instruments and TV cameras to operate during the flyby. Today, computer generated plots and computer animations are used to present the same information.