A Space Habitat

This large space habitat is approximately 50 kilometers long and is home to some 1.2 million people. One end of the habitat (the one closer to the viewer) houses the main docking areas for interplanetary ships (as well as four rarely used docking arms for larger, interstellar vessels and immense Oort mining ships), while the other end houses the industrial fabricator and heat management facilities. By the 35th century, habitats like this house over 60 % of the total human population: the controlled, safe environment of a habitat is usually preferred over the chaos of planetary biospheres - not to mention, constructing a habitat is generally much easier than terraforming an entire world.

Cylinder is the most common habitat design found in the human space; they are rather sturdy, provide plenty of living space and their rotation generates a nice illusion of gravity for surface dwelling beings. Other types of habitats exist as well - the second most common design is a torus, and more unusual designs include free-fall habitats with no artificial gravity whatsoever. Habitats can be on independent orbits around their parent star, but most orbit planets or moons, often in groups or swarms.