As New Klondike suggests, space station cities have planet-based cousins. Science fiction could scarcely survive without its hundreds or thousands of air-protecting cities built under domes, under transparent tents, buried under the surface of moons and planets. The most basic job of these cities as physical constructions is to encapsulate breathable air at breathable pressure. Residents must always be on guard for breaks and blowouts that vent the usable air, void the pressure, or perhaps let in the poisonous atmosphere that has been swirling outside. These are cities protected from the vertical dimension—from meteors, from poisonous gases, or from vacuum that stretches upward to infinity.
Air is the one unregulated and unmetered input into our ordinary urban ecology. It is just there. It is not piped and monitored like water, nor packaged and vended like food and fuel. It is just there as we go about our lives—sometimes dry and sometimes rainy, sometimes smoggy, sometimes crisp and clear after a weather front has swept through. It can do violence when stirred into tornadoes and hurricanes, but usually we notice only its attributes—it’s too hot, too cold, too wet. To imagine air requiring technological intervention is a disquieting novum. Science fiction readers may be so accustomed to domed and buried cities that they scarcely notice, but the idea is actually startling, just as Fritz Leiber points out with the very title of his story.
Consider the dual role of air in the film Total Recall (1990). Mars is a mining colony controlled by a corporation directed by the creepy Vilos Colhaagen, who squeezes his workers by charging for the very air they breathe. When Douglas Quaid, played by Arnold Schwarzenegger, arrives on the planet, workers are being driven to revolt as the price of air keeps rising: “More Freedom! More Air!” At the same time, the half-buried, half-domed city is terribly fragile. Quaid’s arrival on Mars triggers a shoot-up in the arrivals hall that shatters a window and creates a blowout that sweeps people outside—very exciting and very dangerous, although we wonder who would design such a brittle dome, not to mention being stupid enough to arm guards with projectile weapons.
Writers have converged on consensus architecture for the stages of settlement on airless worlds. Allen Steele in Lunar Descent (1991) describes the moon early in the colonization process. Moon miners live in a single company town constructed from a bunch of “low, square and rectangular monocreete buildings clustered together under bulldozed soil, interconnected by subterranean tunnels and above ground crosswalks” (53). The mess hall / meeting hall has a couple of deeply recessed windows onto the drab moonscape, but the workers live inside under a layer of regolith or outside in pressure suits. Larry Niven set his SF detective novel The Patchwork Girl (1980) on the moon at a later stage of development, but the city is still buried under “rock and moondust piled high atop it for meteor protection” (15). The top level has windows, however, enabling an assassin to attempt murder by targeting a victim in his room with a powerful laser aimed from outside, setting up a reverse locked-room mystery. As lunar settlement continues to mature, we may find the characters living on the surface under a dome, as in the opening of Anniversary Day (2001), a recent entry in Kristine Kathryn Rusch’s “Retrieval Artist” series about a science fiction detective in Armstrong City: “Bartholomew Nyquist parked his aircar in one of the hoverlots at the end of the neighborhood. The Dome was dark this morning, even though someone should have started the Dome Daylight program. Maybe they had, deciding that Armstrong was in for a ‘cloudy’ day—terminology he never entirely understood, given that the Moon had no clouds and most people who lived here had been born on the Moon and had never seen a cloud in their entire lives” (15).
The consensus sequence is similar for Mars. South Colony in Robert Heinlein’s classic Red Planet (1949) has a population of a few hundred pioneers, living in double-layered plastic domes connected by tunnels. Arthur C. Clarke’s first published novel, The Sands of Mars (1951), is set sometime in the 1990s in Port Lowell, the largest city on Mars, with two thousand people. Lowellites live inside six nearly invisible plastic domes (the largest half a kilometer across) held up by internal air pressure and intertied by tunnels. Under the domes are “uniform metal houses and a few public buildings” giving the appearance “more of a military camp than a city.” Oxygen is extracted from the oxidized red Martian soil. Residents practice blow-out drills with the goal of getting to cover inside a sealable building within ten seconds.
Heinlein’s and Clarke’s colonists are in the first decade of settlement, but Greg Bear’s Moving Mars (1993) is set on a substantially developed planet in the year 2171. Residents still live underground, but with large domes over the central spaces. Off to the edges of the university, for example, is a maze of old tunnels: “Forty orbits ago—over seventy-five terrestrial years—these tunnels had connected several small pioneer stations. We filed past warrens once used by the earliest families, dark and bitterly cold, kept pressurized in reserve only for dire emergencies” (8). Now Martians live in domed trench complexes, well protected but still vulnerable to pressure-loss accidents and power failures leading to oxygen deprivation and recycler failures. When political crisis explodes, “the white walls and pressure arches [of the new Mars capital] stood out against the ochre and red all around, a beacon for assault” (367)—although it will prove to survive.
Descriptions of cities are secondary in Bear’s narrative, but they are central to Kim Stanley Robinson’s intentions in his trilogy about the terraforming of Mars. He opens the first volume, Red Mars (1993), with a civic festival celebrating Nicosia, the planet’s first fully surface city, coming seventy-five years after initial settlement. “The first town of any size to be built freestanding on the Martian surface; all the buildings were set inside what was in effect an immense clear tent, supported by a nearly invisible frame.” The town is a large triangle on a slope (great views!) with seven radiating avenues and low buildings in Fauvist hues. Its five thousand residents have already divided into ethnic neighborhoods. The air has enough oxygen and weight that the city does not have to be fully sealed, but the atmosphere is still so thin and cold that one cannot survive for long outside without protective suits. “After all those years in Underhill it was hard to grasp…. We’re out of our holes, Maya, we’re on the surface at last” (4–6, 19).
Decades earlier in Robinson’s planetary epic, Martian settlement had started with an expedition camp of modules scattered on the surface, such as might be found in Antarctica or Greenland. Soon Underhill is built as a permanent underground habitat. A double glass dome holds the pressure and keeps out ultraviolet radiation, roofing over a central atrium, with underground rooms branching off. “The sky was a ruby color through the glass panels, and the magnesium struts gleamed like tarnished silver” (163). Settlers built other habitats also largely underground, but with gradually increasing exposure, such as a set of rooms dug into the side of a thirty-meter trench, with three levels of stacked rooms faced with glass, and reflective material on the other side of the trench to direct sunlight. Then the increasingly confident Martians scaled up that model. Japanese immigrants built Senzeni Na, an industrial community at the bottom of Thaumasia Fossae’s deepest canyon. Production facilities on the canyon floor are connected by walktubes because pressure suits were still needed outside. “The town’s actual living quarters were built into the southeast wall of the canyon. A big rectangular section of the cliff had been replaced by glass; behind it was a tall open concourse, backed by five stories of terraced apartments.” The biggest and most beautiful new city is Burroughs, the de facto capital as the base of the United Nations Office of Mars Affairs. It is another cliff city, carved into a set of mesas: “Big sections of the mesas’ vertical sides had been filled by rectangles of mirrored glass, as if postmodern skyscrapers had been turned on the sides and shoved into the hills” (271).
The Martians revolt against Earth domination, UNOMA being the tool of big Earth corporations, but their cities are vulnerable to tent breach. They “lay helpless under the lasers of orbiting UNOMA police ships” (514). Refugees have crowded into Cairo, which is surrounded by UN police. “At 4:30 alarms went off all over the city. The tent had been broached, apparently catastrophically, because a sudden wind whipped west through the streets, and pressure sirens went off in every building. The electricity went off, and just that quick it went from a town to a broken shell, of running figures in walkers and helmets, all of them rushing about, crowding toward