The United States Spacecraft Discovery One is a fictional spaceship featured in the first two novels of the Space Odyssey series by Arthur C. Clarke and in the films 2001: A Space Odyssey (1968) directed by Stanley Kubrick and 2010: The Year We Make Contact (1984) directed by Peter Hyams. The ship is a nuclear-powered interplanetary spaceship, crewed by two men and controlled by the AI on-board computer HAL 9000. The ship is destroyed in the second novel and makes no further appearances. Clarke and Kubrick developed the first novel and film in parallel, but there were some differences to suit the different media. Kubrick dropped the cooling fins of the ship, fearing they would be interpreted as wings. The itinerary of Discovery One in the book is from Earth orbit via gravitational slingshot around Jupiter to Saturn and parking orbit around the moon Iapetus. Kubrick changed this to the simpler route from Earth to Jupiter's moon Europa. For the film, Kubrick built an exceptionally large model of the ship so that focus changes did not give away the true small size to the audience. He also built a large, expensive, rotating carousel for the artificial gravity scenes. Development The spaceship first appears in the novel 2001: A Space Odyssey by science fiction author Arthur C. Clarke and the film of the same name produced and directed by Stanley Kubrick. The book and the film were developed in parallel in a collaboration between Clarke and Kubrick. Despite this, the novelized and filmed appearances of the craft differ. Clarke based the design on ideas that were, or he believed were, scientifically feasible. He gave the ship a hypothetical thermonuclear propulsion system and added huge cooling fins to radiate away the excess heat produced. In the book, Clarke says the fins "looked like the wings of some vast dragonfly" and that they gave the ship a "fleeting resemblance to an old-time sailing-ship". In the film, Kubrick removed the fins because he thought that the audience might interpret them as wings giving the spacecraft the ability to fly through an atmosphere. Early in the development of the movie, Clarke and Kubrick considered having Discovery powered by an Orion type nuclear pulse propulsion system. Kubrick quickly decided against it, both because showing the ship accelerate by a 'putt-putt' method might be "too comic" for film, and because it might be seen as him having