Gravity Assist

The history of the beginning of interplanetary space travel, and the exploration of the solar system only occurred one time and will never happen again. Therefore, it is important in the history of science to preserve an accurate documented account of this history, and the key breakthrough invention that made it possible. It was achieved by the invention of gravity propelled interplanetary space travel popularly known as "gravity-assist trajectories." The invention broke all the high-energy barriers of interplanetary space travel based on the classical theory of space travel using reaction propulsion, and, as a result, made it not only possible to explore the entire solar system, but it also made it easy with small launch vehicles propelled by conventional chemical propulsion. It resulted in all of NASA's high-energy deep-space gravity propelled multi planetary missions used to explore the entire solar system!