Heinlein, Clarke, Bear, and Robinson are all authors who respect engineering. Their Martian cities converge in appearance and structure because the logic of pressure gradients, oxygen pressure, and materials mandate a common form. Moreover, it is a form that readers with basic physics can understand, agree with, or critique. Engineering challenges and solutions are not another decorative gizmo like a bounce tube or dilating door, but rather essential background. In The Sands of Mars, for example, Clarke devoted several paragraphs to the completion of a seventh dome.
Hello, Earth. This is Martin Gibson speaking to you from Port Lowell, Mars. It’s a great day for us here. This morning the new dome was inflated and now the city’s increased its size by almost a half….
You know that it’s impossible to breathe the Martian atmosphere—it’s far too thin and contains practically no oxygen. Port Lowell, our biggest city, is built under six domes of transparent plastic held up by the pressure of the air inside—air which we can breathe comfortably though it’s still much less dense than yours.
For the last year a seventh dome has been under construction, a dome twice as big as any of the others….
Imagine a great circular space half a kilometre across, surrounded by a thick wall of glass bricks twice as high as a man. Through this wall lead the passages to the other domes, and the exits direct on to the brilliant green Martian landscape all around us….
When I entered Dome Seven yesterday, all this great circular space was covered with a thin transparent sheet fastened to the surrounding wall, and lying limp on the ground in huge folds beneath which we had to force our way…. The envelope of the dome is very strong plastic, almost perfectly transparent and quite flexible—a kind of thick cellophane. (422)
Several ensuing paragraphs describe the process of pumping in air and inflating the dome. The scene is perhaps not all that high on the sense-of-wonder scale, but Clarke knew that his own technical bent matched that of his readers.
CITIES UNDER THE SEAS
Underwater cities are the mirror image of lunar and Martian bubble cities. The basic challenge is to maintain a bubble of usable atmosphere within an environment at a different pressure. Dome breach is just as much a fear, but the problem is reversed—keeping massive overpressure at bay and preventing implosion rather than holding in air against explosive escape.
Underwater cities have seldom made for good fiction because of the storytelling problem of setting action in dark ocean depths where neither characters (nor readers/viewers) can see or move freely outside. Consider that submerged movies tend to be submarine warfare thrillers, mysterious shipwreck thrillers, or adventures revolving around alien objects that just happen to have fallen to the ocean floor. In The Abyss (1989), the best of the genre, ambience and action are dark and claustrophobic. A cinematic alternative like the cheesy Captain Nemo and the Underwater City (1969) offers implausibly cheerful interiors and no gestures to technical verisimilitude.
A pulp writer’s favorite option was to ignore science in favor of a mythical Venus with warm seas and networks of underwater cities. Henry Kuttner and C. L. Moore in Fury, originally serialized in Astounding in 1947, posited a set of undersea Venusburgs: “The Earth is long dead, blasted apart, and the human survivors who settled on Venus live in huge citadels beneath the Venusian seas in an atrophying, class-ridden society ruled by the Immortals—genetic mutations who live a thousand years or more.” The domes themselves, both beneath the waters and covering newer colonies on land, are made from “impervium.” What a handy material that is, excusing the authors from actually thinking through the engineering problems so they can focus the plot on tensions and conflicts within the ruling class. Nevertheless, impervium makes the machines for breathing possible: “Now he stood on the land of Venus, with a transparent impervium dome catching rainbows wherever the fugitive sun broke through the cloud blanket…. The free air of Venus was short on oxygen and long on carbon dioxide; it was breathable, but not vintage atmosphere…. Here, under the dome, the atmospheric ingredients were carefully balanced. Necessary, of course—just as the impervium shell itself seemed necessary against the fecund insanity that teemed the Venusian lands” (93).
Isaac Asimov left only part of his science at the door when he wrote for the juvenile market as Paul French, describing an entire network of fifty undersea cities in Lucky Starr and the Oceans of Venus (1954). Because the atmosphere contains no oxygen, Venusians make the planet livable by using electrolysis to oxygenate their bubble cities. Rather than Kuttner’s implausible mile-deep citadels, these lie just below the ocean surface so their tops nearly break into the sky at low tide. The dome is two-layered, with carbon dioxide sandwiched in between to absorb shocks. Honeycomb structures between the layers minimize danger, and internal barriers can shut off different sections of the city in case of breach (the first half of the book centers on threatened sabotage). This said, however, the domes themselves are made from a handy super-duper plastic called transite, which is completely insoluble, doesn’t etch, won’t change chemically in reaction with the ocean, and never gets encrusted with slime or Venusian barnacle equivalents. Moreover, the domes are actually supported by power beams that are, explains a city official, “diamagnetic force fields in steel housings. It looks as though steel beams are supporting the dome, but that’s not so. Steel just isn’t strong enough. It’s the force fields that do it” (58).
Maureen McHugh in Half the Day Is Night (1994) made a much more serious stab at imagining underwater cities, in this case a set of cities two hundred meters under the Caribbean that constitute the nation of Caribe. The plot itself—a story of two innocent individuals who slowly realize that they have been caught up in political and corporate maneuvers and scheme to escape—does not require the undersea setting. Much of the action occurs in the boardrooms, cheap hotels, and mean streets that are the familiar settings of noir and thriller fiction. Submarines rather than ferries connect the cities, buses operate on city streets, including the Caribe equivalent of Kenyan matatu and similar vehicles of the third-world poor. The ethnicity of the French Vietnamese and Chinese American protagonists contrasts with the darker-skinned Haitians of Caribe, paralleling the plot tension of individuals from the global North caught up in problems of the global South that drives many stories of intrigue, from Graham Greene novels to the 1982 film The Year of Living Dangerously.
Nevertheless, McHugh refrains from introducing impervium or transite or diamagnetic force fields and pays particular attention to the problems of temperature and air. She never describes the domes or containment systems themselves, but the ambient cold of the deep ocean overburdens heating systems and renders the cities always chill. Only a handful of construction workers and fish jockeys work in the sea outside, taking drugs to speed their metabolism and eating vast piles of carbohydrates to survive the cold. Inside, pressure variations between upper and lower levels affect the composition and quality of the atmosphere. The rich get clean, dry air. The poor on the lower levels breathe damp, oxygen-poor air laden with odors and pollutants because recirculation systems are ill-maintained. Open fires are illegal, a stricture violated in poor districts, but richer residents still drive cars with internal combustion engines. Air is not yet metered like water and power, notes one resident, but the implication hovers that Caribe is not that far removed from New Klondike.
SUPERSIZE US
In 1974, author and editor Frederik Pohl had a brief conversation with New York mayor John Lindsay about whether the city was governable (Lindsay thought that the basic problem was not enough tax revenue). The next year Pohl published The Years of the City, five chronologically sequential novellas about the future of New York. The unifying concern is the problem of governance as the changing cast of characters deal with labor union power and racketeering, political corruption, and changing legal systems.
In the third novella, “The Blister,” Manhattan is being enclosed under one large dome up from the Battery to Canal Street and another over the middle of the island, with a smaller dome to connect them, making a sort of lopsided dumbbell shape like “two humps on a camel, the tall igloo one down around lower Manhattan, the lower connecting bridge from Canal Street to the twenties, the big elongated one covering midtown and Central Park” (177). Pohl might have