As Richard Rhodes points out in this article, Robert H. Goddard’s attempt to produce a workable rocket propelled by a series of controlled explosions failed and he went on to devise the liquid-fuel system that became the basis for most of his subsequent work.
Yet the concept of a “machine-gun” rocket did not die with Goddard in 1945. In the academic year of 1958-59 the physicist Freeman Dyson became involved with Theodore B. Taylor and other scientists on Project Orion at Point Loma, California, aimed at developing a spaceship powered by small, controlled nuclear explosions. Dyson telk the story in his recent memoir, Disturbing the Universe: