2010: Odyssey Two

2010: Odyssey Two is a 1982 science fiction novel by British writer Arthur C. Clarke. It is the sequel to his 1968 novel 2001: A Space Odyssey, though Clarke changed some elements of the story to align with the film version of 2001.

Set in the year 2010, nine years after the failure of the Discovery One mission to Jupiter, the plot centres on a joint Soviet-US mission aboard the Soviet spacecraft Alexei Leonov. The mission has several objectives, including salvaging the spaceship Discovery and investigating the mysterious "monolith" discovered by Dave Bowman in 2001: A Space Odyssey. It was nominated for the Hugo Award for Best Novel in 1983. The novel was adapted for the screen by Peter Hyams and released as the film 2010: The Year We Make Contact in 1984.

A joint Soviet-American crew, including Heywood Floyd, on the Soviet spacecraft Alexei Leonov (named after the cosmonaut) arrives to discover what went wrong with the earlier mission, to investigate the monolith in orbit around Jupiter, and to resolve the disappearance of David Bowman. They hypothesize that much of this information is locked away on the now-abandoned Discovery One. The Soviets have an advanced new "Sakharov" drive which will propel them to Jupiter ahead of the American Discovery Two, so Floyd is assigned to the Leonov crew.

However, a Chinese space station rockets out of Earth orbit, revealing itself to be the interplanetary spacecraft Tsien, also aimed at Jupiter. The Leonov crewmembers think the Chinese are on a one-way trip due to its speed, but Floyd surmises that due to the large water content of Europa they intend to land there and use the water content to refuel. The Tsien's daring mission ends in failure, when it is destroyed by an indigenous lifeform on Europa. The only survivor, Professor Chang, radios the story to the Leonov, confirming that life exists on the moon; it is presumed that he dies when his spacesuit air supply runs out.

The Leonov survives a dangerous aerobraking around Jupiter and arrives at Discovery (One). Mission crewmember and HAL 9000's creator, Dr. Chandra, reactivates the computer to ascertain the cause of its earlier aberrant behavior. After some time, Floyd is speaking to Vasili Orlov on board, and Orlov, for an instant, sees the Monolith, dubbed "Big Brother", open into a Stargate again as David Bowman escapes from the Monolith's dimension back into ours. Unfortunately, Dr. Floyd is facing the wrong direction and therefore does not see this.

A sequence of scenes follows the explorations of David Bowman, who has been transformed into a non-corporeal, energy-based lifeform, much like the aliens controlling the monoliths. During his journey, the avatar of Bowman appears on Earth, making contact with significant individuals from his past: He visits his mother and brushes her hair shortly before she dies, and he appears to his ex-girlfriend on her television screen. The aliens are using Bowman as a probe to learn about humankind. He then returns to the Jupiter system to explore beneath the ice of Europa, where he finds aquatic lifeforms, and under the clouds of Jupiter, where he discovers gaseous life-forms. Both are primitive, but the aliens deem the Europan creatures to have evolutionary potential.

An apparition of Bowman appears before Floyd, warning him that they must leave Jupiter within fifteen days. Floyd has difficulty convincing the rest of the crew at first, but then the monolith vanishes from orbit.

The Leonov crew devises a plan to use the Discovery (One) as a "booster rocket", enabling them to return to Earth ahead of schedule. HAL and the Discovery (One) will be trapped in Jupiter's orbit, with insufficient fuel to escape. The crew are worried that HAL will have the same neurosis on discovering that he will be abandoned yet again, so Chandra must convince HAL that the human crew is in danger.