The United States Spacecraft Discovery One was a nuclear-powered interplanetary fictional spaceship controlled by the AI onboard computer HAL 9000 from the first two novels of the Space Odyssey series and the movies 2001: A Space Odyssey and 2010: The Year We Make Contact.
This spaceship is founded on solidly conceived, yet unrealized science. One major concession in its appearance, for the purpose of reducing confusion, was to eliminate the huge cooling "wings" which would be needed to radiate the heat produced by its hypothetical thermonuclear propulsion system. The movie's producer/director Stanley Kubrick thought that the audience might interpret the wings as meaning that the spacecraft was intended to fly through an atmosphere.
The Discovery One was named after Captain Robert Scott's sailing ship RRS Discovery, which was launched in 1901. Writer Arthur C. Clarke used to visit this ship when it was moored in London. It shares its name with a real spacecraft, the Space Shuttle orbiter Discovery (OV-103).
In the novel 2001: A Space Odyssey, the Discovery One is described as being about 460 feet (140 meters) long (the 2010 movie mentions 800 feet) and powered by a nuclear plasma drive, separated by 275 feet (84 m) of tankage and structure, from the spherical part of the spaceship where the crew quarters, the computer, flight controls, small auxiliary craft, and instrumentation are located. In the crew's centrifuge, the crewmen would have enjoyed Moon-like gravitational conditions. This would be where they spend most of their time, and where the three hibernating astronauts rested in their compartments. The piloting, navigation, and other occasional tasks could take place in the zero-gravity command module.
Other sections of the crewmen's sphere would include the pod bay, where three one-man repair and inspection craft would be kept, and the spaceship's primary HAL 9000 mainframe computer with its level-upon-level of memory storage and digital processing units. Because of the lack of aerodynamic design and its immense size, the Discovery One would be assembled in and launched from orbit. As described in the novel, the Discovery One was originally intended to survey the Jovian system, but its mission was changed to go to Saturn and investigate the destination of the signal from the black monolith at the crater Tycho. As a result, the mission became a one-way trip to Saturn and its moon Iapetus. After investigating alien artifacts at Saturn and Iapetus, the preliminary plan is for all five members of the crew to enter suspended animation for an indefinite period of time. Eventually, it was hoped that a much larger and more powerful Discovery Two would be built that could make it to Iapetus and return with everyone in hibernation.
The ship's centrifuge was a spinning band of deck, mounted inside the crew compartment, that used centrifugal force to simulate the effects of gravity. It was the primary living and work area, featuring consoles, panels, screens, and devices. In the movie, there was Earth gravity in the centrifuge. All other points on the ship, including the command bridge, were micro-g environments where the crew members used Velcro shoes to attach themselves to the floor. There was an automated kitchen developed with the assistance of General Mills; a ship-to-Earth communications center; and a complete medical section where the astronauts underwent regular automated checkups with results and any diagnosis of deficiencies dislayed directly on a readout screen.
The Discovery is described as a very large ship that could be handled by only two astronauts (David Bowman and Frank Poole), along with the HAL 9000. In the book IBM predicted that computer development would have advanced to such an extent that the mission could be undertaken with all the astronauts placed in hibernation. It was said to be desired, however, that regular communications be maintained throughout the voyage between the pilot and copilot and mission control back on Earth. During communication, account was taken of the elapsed time for electromagnetic waves crossing space between the spaceship and the Earth. For example, Poole is depicted watching a prerecorded birthday message from his family, rather than interacting with them in real time. Such a conversation is not possible because messages take over 30 minutes to transmit between Jupiter and Earth. Naturally, this time would depend on the relative positions of the bodies in the Solar System at any given moment.
After the malfunction of HAL, Bowman deactivated the computer, thus effectively isolating himself on board the Discovery. In the movie, when the spacecraft arrives at Jupiter, it encounters TMA-1's considerably larger 'Big Brother', 'TMA-2', at the Jupiter/Io L1 point. The novel is basically the same with Discovery in orbit around Saturn's moon Iapetus instead. In both versions Bowman leaves Discovery to examine the monolith and is taken inside it.
The novel and movie 2010: Odyssey Two follows the 2001: A Space Odyssey movie ending rather than the novel.
After finding out that Discovery's orbit is failing, a joint Soviet-US mission (including Heywood Floyd) travels to Jupiter aboard the spacecraft Alexei Leonov to intercept and board Discovery believing that it harbours many of the answers to the mysteries surrounding the 2001 mission. Leonov docks with Discovery, reactivates the on-board systems, and stabilizes its orbit. Hal's creator, Dr. Chandra, is sent to reactivate the HAL 9000 computer and gather any data he can regarding the previous mission.
Later on, an apparition of Dave Bowman appears, warning Floyd that Leonov must leave Jupiter within two days. Floyd asks what will happen at that time, and Bowman replies, 'Something wonderful'. Floyd has difficulty convincing the rest of the crew, at first, but a dark spot on Jupiter begins to form and starts growing. HAL's telescope reveals that the “Great Black Spot” is in fact a vast population of monoliths increasing at a geometric rate. (The film accelerates the pace from the novel, both shortening Bowman's deadline from fifteen days, and making the spot grow faster.)
Initially it was planned to inject Discovery on an Earth-bound trajectory (though it would not arrive for some years); however, when faced with Bowman's warning, the Leonov crew devises a plan to use Discovery as a 'booster rocket', enabling them to return to Earth ahead of schedule, but leaving Discovery in a elliptical orbit of Jupiter. The crew worries that Hal will have the same neuroses on discovering that he will be abandoned, and Chandra convinces HAL that the human crew is in danger and must leave.
After detaching itself from Discovery, Leonov makes a hasty exit from the Jupiter system, just in time to witness the Monoliths engulf Jupiter. Through a mechanism that the novel only partially explains, these monoliths increase Jupiter's density until the planet achieves nuclear fusion, becoming a small star.
As Leonov leaves Jupiter, Bowman instructs HAL to begin repeatedly broadcasting the message:
ALL THESE WORLDS ARE YOURS EXCEPT EUROPA. ATTEMPT NO LANDINGS THERE.The movie version, as part of its heightened Cold War emphasis, adds the words:
USE THEM TOGETHER. USE THEM IN PEACE.The new star, which Earth eventually dubs "Lucifer", destroys Discovery. HAL is transformed into the same kind of entity as David Bowman and becomes Bowman's companion.