Sid Meier's Alpha Centauri (sometimes abbreviated to SMAC or Alpha Centauri) is a 4X turn-based strategic computer game created by Brian Reynolds and Sid Meier under the auspices of Firaxis Games in 1999. It is based on a fictional attempt by human beings to colonize a planet in the Alpha Centauri star system. It picks up where Meier and Reynolds' earlier titles, Civilization I and Civilization II, left off. An expansion pack called Sid Meier's Alien Crossfire (aka SMACX or just SMAX) was also released. Although popular with gamers, the game never reached the heights of success of the Civilization games. Pre-patched versions of Alpha Centauri and Alien Crossfire were later bundled together in the Alpha Centauri Planetary Pack. The game has also been released under the Sold-Out Software label.
According to the storyline of the game, humanity is destroying itself through war, famine, pollution, and poverty, but before it can complete self-destruction, the U.N. launches an enormous colonization starship called Unity. The Unity is destined for a planet in the Alpha Centauri system. This planet, named "Chiron" (but often just called "Planet") is very similar to Earth.
However, before the starship fully reaches Planet, forty years into the journey, the Unity suffers a core malfunction, awakening many of the crew, who then proceed to fix the malfunction. Before they are done, however, the captain of Unity, Garland, is assassinated by an unknown assailant. The rest of the crew is awakened soon after.
When news of the assassination spread, the crew panics, the ship beginning to break apart due to mishandling. Seven leaders take up the challenge of leading a faction onto Planet by use of colony pods. (The game's video introduction depicts an eighth escape pod separating from the Unity, only to explode shortly thereafter.) Unity breaks up in high orbit, supplies, components, and factions spread everywhere. After the colony pods land, the player comes in to take control and aid their faction to victory over the others.