Top 10 List of Scrapped Spaceships. Favorite designs are the Wernher Von Braun Ferry Rocket, Project Orion, an atomic spaceship, Boeing X-20 Dyna-Soar and the Lockheed X-33 Venture Star. In "Almost Famous: The X-20 DynaSoar," The Living Moon article reveals: "The semi-winged DynaSoar evolved greatly. The basic idea was to lob the bird into low Earth orbit and skip across the upper atmosphere like a rock across a pond, a concept then known as "dynamic soaring." Then some wag decided to shorten the term to "DynaSoar"-perhaps forgetting the fate that awaited the craft's prehistoric namesakes!...Then a proposal was developed that would have seen three stages in development-DynaSoar I, II, III, and finally the operational DynaSoar Manned Orbital Weapons System." The X-planes seem certainly direct ancestors of present X-37 Orbital Test Vehcile, history implies a weapons program and reason for strong protests from Russia and India concerning X-37 mission.
George Dyson, science historian, reviews Project Orion in a TED talk below. Freeman Dyson, George's father, worked on project to build 4,000 ton nuclear powered spaceship to travel to Saturn.