How can we design the conditions for humans to thrive in outer space? This question is at the core of SOM’s specially commissioned installation for “Unknown Unknowns,” the 23rd Triennale Milano International Exhibition.

While sound and video are the most striking elements of the installation, “Decalogue for Space Architecture” began as a written text—an essay that emerged through conversations with the curator, astrophysicist Ersilia Vaudo, and a team of architects and engineers at SOM who have pursued concepts for space habitats through years of design and research.

Here we present the full text of the Decalogue: ten principles that should define a human-centered design approach for life beyond Earth.

Confronting the forces that govern the universe

All matter originated from a singular event which we know today as the birth of the universe. Matter follows the laws of the universe in ways we still cannot fully articulate, and yet it has been discovered that there is a real connection across small and large objects, between their different states and across space. Humans share in this same interconnectivity throughout the material universe and its metamorphosis. We are inseparable from this continuum, and at the same time have the ability to create and explore possibilities beyond natural phenomena. In this sense, architecture is a self-directed shaping of the universe filtered through the human mind.

Our awareness of this larger reality was long concealed by our existence within the protective envelope of Earth’s atmosphere and magnetosphere. While the natural world around us evolved its material forms incrementally through the competitive process of natural selection, wasting little in its search for idealized forms, humans most often created form crudely—overcoming gravity, weather, and time through trial and error and brute force. Though we succeeded at building habitats, our construction methods often had less immediately visible consequences, like the excessive release of carbon into the atmosphere—which, when aggregated across time and geography, has threatened the very conditions that allowed our species to evolve in the first place. Only now are we beginning to comprehend how complex space-making is, and how reliant we are on what our planet already provides for us. Leaving Earth, however, requires us to grapple more honestly with the forces that shape our reality.

Beyond Earth, we must face the truth that the universe is indifferent to humanity’s survival. Just the act of launching a rocket into space takes tremendous energy; we are forced to optimize every gram, lest the mass of our payload doom the endeavor from the start. Once in space, we confront an environment which presents fundamentally different challenges. Whereas on Earth, our task today is finding ways to better harmonize our existence with the planet and its ecosystems, in space we must insert something foreign—a miniscule pocket of habitable space in a hostile universe. In effect, the challenge is to create an “Earth” in miniature—a container which protects its inhabitants from its surroundings, artificially creating the conditions for life to thrive. To realize this environment stretches our current understanding of science and technology to the limit. We must find the purest, most efficient expression of the enclosure that can be fabricated on Earth, survive the trip to the Moon, and endure the vacuum of space. To do this, we must recenter our design thinking on both the forces that govern the cosmos and the human experience of these phenomena. Accordingly, we have divided our Decalogue for Space Architecture into two parts—those principles focused on the creation of the habitat and those centered on the human experience.

Part I: Habitat

Gravity

The human body has evolved to deal with the constant force of gravity. To thrive in space, we must seek out gravity or reproduce it.

The constant pressure that gravity exerts on the body is essential to our survival. In space, without the need to resist gravity, our bone density slowly degrades and our muscles atrophy. In fact, the absence of gravity affects nearly every aspect of our physiology: our blood circulation is disrupted, we experience motion sickness, and our immune system is suppressed.

To survive in the long term, we must either seek out gravity—by settling in low-G environments, such as the Moon or Mars—or artificially generate gravity by spinning the habitat. Even small amounts of acceleration could make it possible for humans to maintain their bodies with minimal exercise and strength training.

Extremes

Outside of the Earth’s atmosphere, architecture must protect us from swings in temperature.

In space, outside of the Earth’s protective shield, temperatures vary dramatically—between hundreds of degrees in areas facing the sun and near absolute zero in the shade. Our celestial neighbor Mars shows us what happens when a planet has lost its atmosphere. Although it has a similar cycle of days and seasons, the atmospheric pressure on Mars is only about one percent that of Earth. With virtually no thermal protection, the surface temperature swings by as much as 100 degrees Celsius on a typical day.

Earth’s atmosphere, a layer of gas dozens of kilometers thick, protects us from these extremes. In space, architecture must accomplish the same with just a few centimeters of thickness.

Cycles

Material cycles are the foundation for life on Earth. Balancing these cycles is a crucial challenge for sustaining life in space.

At every moment, elements such as nitrogen, carbon, and oxygen are being processed by living and non-living things. Atoms travel between the Earth and its atmosphere, released or captured by natural processes as small as bacteria decomposing a leaf, or as large as the shifting of tectonic plates. These cycles are the foundation for life as we know it. But when they become unbalanced—as the carbon cycle is today due to human activity—then the conditions for survival become more difficult.

In space, we will not have generations to realize that a cycle is broken. In a small, enclosed space habitat, any imbalance can quickly become dangerous. We must aspire to design completely closed cycles to create a suitable habitation.

Rays

In a universe flooded with fast-moving and destructive particles, architecture is our first line of defense.

Throughout the universe, supernovas, neutron stars, and black holes launch atoms at nearly the speed of light. On Earth, we do not encounter these particles—our magnetic field and atmosphere provide the barriers to stop them. But cosmic rays pose a lethal danger to humans in space.

The sun also flings out charged particles, and occasionally it erupts in powerful bursts of plasma—a phenomenon known as coronal mass ejections. None of Earth’s life forms can survive exposure to radiation of this magnitude.

For long-term settlement in space, our habitats must serve as a shield. The challenge, however, is balancing the cost of launching these materials with the protection they can provide.

Mass

Transporting building materials into space is prohibitively expensive. We must minimize the resources brought from Earth.

Moving mass in and out of a gravitational field requires great amounts of energy, and thus great expense. New technologies such as reusable rockets could eventually reduce costs for spaceflight, but this alone will not solve the basic challenge of transporting building materials for a long-term settlement.

An efficient use of materials is paramount—especially when those materials must come from Earth. Each gram that we reduce in the payload will save ten to twenty grams in rocket fuel. Ultimately the best solution is to use resources that are available at the destination: we must find ways to build with elements that exist on the surfaces of the Moon and other planets.

Part II: Human Experience

Confinement

Architecture in space should provide relief from feelings of isolation, while also allowing for privacy.

Humans are not built for an isolated existence—we cannot thrive without a diversity of interaction. At the same time, our need for privacy is essential. Habitats in space should allow residents to find the right balance—between sociability and solitude, community and privacy.

Extraterrestrial architecture should provide much of the rich variety of open and private spaces that exist in communities on Earth. Besides places to be alone, there must be spaces for two people to be together, for a small team to gather, or for an entire community to assemble.

Windows are an essential component of shelters in even the most inhospitable environments. Although breaking the protective envelope increases risk, the psychological benefits of a view outside are indispensable.

Symbiosis

A space habitat should be an ecosystem where humans and other species thrive together.

A recurring theme in science fiction is our relationship with technology—humans and their machines setting out to explore the universe. In reality, long-term space exploration will depend not only on technology, but also on biology.

Plants play many vital roles in space habitat design. They can provide a source of fresh food, which is especially important for a community living in isolation. Plants purify the atmosphere and enhance the range of sensory experience. Being in the presence of plants enhances psychological well-being. Even the inedible parts of plants can serve as feedstock for useful materials.

Finding the right balance between human and plant life on board is an essential challenge. Biodiversity must be integrated into the architecture.

Resilience

To keep humans safe in space, we must design a habitat that can withstand any emergency.

The goal of building codes on Earth is to provide safe egress from a structure in case of catastrophic event, such as a fire or earthquake. If everyone manages to exit the building alive, the architect and engineer have done their job. In space, the opposite is true. There is no safety outside—the outdoor environment is more deadly than almost any conceivable indoor emergency. The structure must be robust enough to allow the crew to remain safely inside.

Achieving this goal will require multiple levels of redundancy in every system. For instance, a growing settlement could be subdivided into segments, with at least two means of egress from every space into another individually pressurized space. The planning and architecture must eliminate any single points of failure.

Light

Dynamic lighting design can reinforce circadian rhythms and enhance well-being.

Human evolution has taken place in the 24-hour cycle of light and darkness created by our planet’s rotation. Our need for sleep, and the detrimental effects of interrupting our circadian cycle, are well known.

Other places in the solar system have a pattern of light and darkness that is very different from Earth. Fourteen days of sunlight follows fourteen days of darkness on the majority of the Moon’s surface, while sunlight is uninterrupted for most of the year on its south pole.

Artificial lighting can reinforce our natural circadian rhythms. Typical mechanical light, toggling between “on” and “off,” does not provide the variations in intensity and color that are part of a natural day and night cycle. Instead, a more dynamic and nuanced approach to lighting design can create a life-sustaining variety and rhythm.

Color

Recreating the variety of color found on Earth can bring emotional and psychological benefits in space.

The dynamic phenomenon of color is a defining characteristic of our natural environment. In contrast, the gray surface of the Moon presents a “magnificent desolation,” as astronaut Buzz Aldrin described it; the only burst of color is the Earth itself, hanging motionless in the sky.

The strategic use of color has a long history in the field of exploration. The polar explorer Fridtjof Nansen painted his ship in bright colors, anticipating the long arctic days spent in featureless white. More recently, designers of Antarctic research stations have sought the expertise of color psychologists to help mitigate sensory deprivation.

Supportive uses of color and lighting can bring profound emotional benefits. Within the enclosed space habitat, colors that change over time can reduce feelings of crowding or confinement.

Decalogue for Space Architecture