Nuclear spacecraft propulsion

Source: Wikipedia. Pages: 35. Chapters: Nuclear pulse propulsion, Nuclear thermal rocket, Nuclear salt-water rocket, Bussard ramjet, Fusion rocket, Nuclear photonic rocket, Nuclear electric rocket, Antimatter catalyzed nuclear pulse propulsion, Project Orion, Gas core reactor rocket, NERVA, Project Rover, British Rail flying saucer, Fission-fragment rocket, Mini-Mag Orion, Project Prometheus, Radioisotope rocket, Space Nuclear Propulsion Office, Project Longshot, Charles Osmond Frederick, Fission sail, RD-0410, Helios, Nuclear lightbulb, Project Timberwind, Project Icarus, ICAN-II, AIMStar, 11B97. Excerpt: Project Orion was a study of a spacecraft intended to be directly propelled by a series of explosions of atomic bombs behind the craft (Nuclear pulse propulsion). Early versions of this vehicle were proposed to have taken off from the ground with significant associated nuclear fallout; later versions were presented for use only in space. A 1955 Los Alamos Laboratory document states (without offering references) that general proposals were first made by Stanislaw Ulam in 1946, and that preliminary calculations were made by F. Reines and Ulam in a Los Alamos memorandum dated 1947. The actual project, initiated in 1958, was led by Ted Taylor at General Atomics and physicist Freeman Dyson, who at Taylor's request took a year away from the Institute for Advanced Study in Princeton to work on the project. By using energetic nuclear power, the Orion concept offered high thrust and high specific impulse, or propellant efficiency, at the same time. As a qualitative comparison, traditional chemical rockets-such as the Saturn V that took the Apollo program to the Moon-produce high thrust with low specific impulse, whereas electric ion engines produce a small amount of thrust very efficiently. Orion would have offered performance greater than the most advanced conventional or nuclear rocket engines then under consideration. Supporters of Project Orion felt that it had potential for cheap interplanetary travel, but it lost political approval over concerns with fallout from its propulsion. The Partial Test Ban Treaty of 1963 is generally acknowledged to have ended the project. During the late 1940s, Stanislaw Ulam realized that nuclear explosions could not yet be realistically contained in a combustion chamber. Such a project did briefly exist, named Helios, but while its theoretical performance was similar to that of what would become the Orion, the lack of materials that could withstand the propulsion generating process meant that Helios never got beyond the drawing board. Inst