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 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.

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