Sid Meier's Civilization: Beyond Earth is now available for pre-purchase on Steam, as noted by Steam News. The game's Steam page therefore now reveals the preorder bonuses for the sci-fi turn-based strategy game:

Pre-purchase Sid Meier’s Civilization: Beyond Earth and receive the Exoplanets Map Pack for free.

The Exoplanets Map Pack includes six custom maps inspired by real-world exoplanets. Specialized scripts produce randomized geographic layouts each time a new game begins, allowing for even more replayability on new alien worlds.

• Kepler 186f: This lush forest planet is one of the oldest known Earth-like planets.
• Rigil Khantoris Bb: Orbiting the closest star to the solar system, the historical records of this arid continental planet’s settlement are well-preserved.
• Tau Ceti d: This planet of seas and archipelagos features a booming biodiversity and a wealth of resources.
• Mu Arae f: Tidally locked in orbit around a weak star, the southern hemisphere of this planet is a blistering desert where the sun never sets, while the northern hemisphere is perpetually in frozen darkness.
• 82 Eridani e: An alien world of scarce water and wracked by tectonic forces.
• Eta Vulpeculae b: A mysterious new discovery with unknown terrain.