The concepts ofspace stations andspace habitats feature inscience fiction. The difference between the two is that habitats are larger and more complex structures intended as permanent homes for substantial populations (thoughgeneration ships also fit this description, they are usually not considered space habitats as they are heading for a destination[1]), but the line between the two is fuzzy with significant overlap and the term space station is sometimes used for both concepts.[2][3] The first such artificial satellite in fiction wasEdward Everett Hale's "The Brick Moon" in 1869,[2][4] a sphere of bricks 61 meters across accidentally launched into orbit around the Earth with people still onboard.[1][5]
Space stations started appearing frequently in science fiction works following the release of the 1949popular science bookThe Conquest of Space byWilly Ley, which deals with the subject.[2] They serve several disparate functions in different works. Among these are industry, health benefits due to low gravity, prisons, and means to observe alien worlds.[6] Several early works of the genre focused on space stations inEarth orbit or atLagrange points as relay stations for interplanetary communication or transportation.[2] Military uses for space stations appear, but being portrayed as a direct threat is comparatively rare.[2][6] Occasionally, the space stations are connected to the planet they are orbiting via aspace elevator, a concept which was introduced to science fiction separately byArthur C. Clarke andCharles Sheffield in 1979.[6] In fiction, space stations were largely superseded by space habitats in the final quarter of the 20th century.[2]
The first fictional space habitat proper (not counting the unintentional one in "The Brick Moon") was featured in the 1931 novella "The Prince of Space" byJack Williamson;[1] it is a cylinder 1,520 metres (5,000 ft) long and wide which rotates to createartificial gravity.[7]
Besides cylinders, space habitats in fiction also come in the shapes of spheres, wheels, and hollowed-out asteroids, among others. A more unusual depiction is seen inJames Blish's 1955 bookEarthman, Come Home—as well as the rest of hisCities in Flight series—where they are cities roaming through space.[1]
Space habitats featured only intermittently in science fiction until 1977, whenGerard K. O'Neill'sspeculative nonfiction bookThe High Frontier: Human Colonies in Space was published and went on to inspire numerous authors.[3][4][7] The works inspired by O'Neill range fromutopian to dystopian; the latter foresee a wide variety of problems with space habitats, including dilapidation while humans are still living there, vulnerability to sabotage, and the potential for a wealthy elite in space to exploit the inhabitants of Earth.[7]
A recurring theme in these works is tensions between the inhabitants of the habitats and planet-dwellers.[1] Inasmuch as they provide opportunities for telling stories of isolated populations with diverse cultures, space habitats serve the same function in space that islands serve on Earth in earlierspeculative fiction,[3] though some science fiction works such as the TV seriesStar Trek: Deep Space Nine andBabylon 5 take the opposite approach of portraying space habitats as multicultural centres where members of different spacefaring civilizations coexist peacefully.[7]
