Steve Summerford is a landscape architect, urban planner and a concept illustrator working with Icarus Interstellar on Project Hyperion, a study of manned interstellar flight and colonization of other worlds.
Imagine for a moment a typical picturesque Saturday morning.
You wake up, feeling refreshed or perhaps a bit groggy, but to the arrival of sunlight through a window nonetheless. Maybe first on the agenda is brewing coffee or taking the dog out, or perhaps putting on some clothes.
As you step outside your front door you look up at the sky above; only in this case, it's no longer yours. Instead it's being borrowed, slowly receding as you, your dog, and your entire neighborhood accelerate toward unknown horizons in search of new skies.
Sunlight still beats down on your skin, but it is filtered through a tinted protective encapsulation that is your neighborhood's only separation from the emptiness of space beyond. Yet you're unbothered by this; new suns will inevitably come, as you're a pioneer after all, on a mission to explore distant worlds.
Despite the inherent differences between life on Earth and that aboard a colonial "worldship," much can be done to ensure that life 'truly' abroad is as similar to terrestrial life as possible. While no successful spacecraft can exist without a complete integration of vessel and mechanics, the scope of this discussion temporarily divorces such devices. It will instead focus on the human experiential component and how design practices refined on Earth over the course of centuries can serve as valuable tools for the design of a sustainable space colony, accommodating as many as 10,000 permanent colonists.
Germane to this discussion would be the mention of a comprehensive study conducted in 1975 by a team of NASA researchers, independent collaborators, and Stanford University students, titled "Space Settlements: A Design Study" ( NASA SP-413 ).
Despite being nearly four decades old, much of the research contained within is extremely relevant today, as it deals with largely unchanging issues such as spatial allotment on a per person basis and the efficiency of potential worldship geometries. As such, it is considered a seminal study to be expounded upon as progress is made toward designing and building such a worldship, and will be referenced throughout this discussion.
The opening paragraph depicts a scenario many would not have considered if asked to describe a typical morning living within a space colony, yet I believe it to be both accurate and quite necessary. Presently, images often associated with space travel and its inhabitation conjure a very utilitarian designed framework, clad in lightweight metals and sterile fabrics, with bits of daily accoutrement floating aimlessly about.
While space station predecessors such as SkyLab, Mir, and the International Space Station (ISS) may have employed such practical, bare-bones design solutions, attempting to emulate these habitats with the goal of providing any semblance of a permanent 'home' for colonists would be futile. While such methods may be relatively economic, the development and implementation of a perpetual worldship with permanent colonists requires the establishment of an entirely new design criterion, much more closely aligned with architectural and spatial design practices found here on earth.
Certainly some portions of a colonial worldship could resemble the space laboratories of today -- exploiting weightlessness and practical design -- however the majority of occupiable living space arguably should more closely emulate neighborhoods and small towns found here on Earth.
Perhaps an oversimplified metaphor could be the notion of your familiar neighborhood and its associated town centers, merely encapsulated within a protective enclosure. Instead of imagery derived from sources such as movies, TV, and mid-century science fiction, think instead about what you would require for happy and healthy living conditions on a daily basis for the rest of your life.
Sure, conditions similar to those found aboard a cruise ship may suffice for a few weeks, but are only truly bearable due to the reality of its impermanence -- at the end of the journey, you will ultimately return to your home.
According to the 'Space Settlements' study, the average human requires minimum living quarters of approximately 50 m2 (500 ft2) in order to be comfortable -- not accounting for extraneous spatial experiences such as agriculture, recreation, shopping/dining, etc. When all factors necessary for normal living conditions are accounted for and averaged out across a colony of 10,000 inhabitants, the encompassing area climbs to approximately 150 m2 (1,600 ft2) per person.
The study goes further to project minimum volumetric space requirements as well, and includes a very detailed breakdown of how the space should be allotted, providing a significant benchmark for future development.
In total, one of the truly invaluable contributions made by the report is a reference point to begin scaling such a worldship. Such a vessel would require approximately 670,000 m2 of 'projected' living space and a pressurized volume of nearly 17,400,000 m3 -- a structure containing roughly as much livable area as three Empire State buildings. Contrast that to present day space capsules and modules that barely challenge the typical single family house, and the enormity of such a vessel begins to materialize.
Projected Living Space
Space travel today is synonymous with weightlessness. Ironically enough, such weightlessness is both one of the most advantageous and disadvantageous aspects inherent to developing a space colony.
Obvious advantages pertain to material and construction weight issues, maneuverability, scientific studies, etc. However, decades of research have demonstrated prolonged weightlessness to be extremely detrimental to the human body. To combat such debilitating side effects from perpetual exposure to zero-G environs, any such worldship design must generate its own measurable gravity -- a feat attainable through rotation about a central axis.
Knowing that the space colony must be able to rotate creates a huge driver behind the macro design of such a vessel. Capitalizing on the principles of centrifugal force, it is estimated that about 70 percent of Earth's gravity will be needed to safely allow for long term occupation, resulting in a gentle rotational rate of just 1 RPM.
As a design provision, such requirements suggest the implementation of simple geometries that are symmetrical about a central axis, such as cylinders, dumbbells, toruses, and spheres -- all of which are explored in great detail in the aforementioned research study.
Each geometry or combination thereof must be evaluated on its efficiency with respect to available projected living space, or rather, how much area is available perpendicular to the rotational axis where appreciable gravity can be experienced and human inhabitation can safely exist.
Imagine in the instance of a torus; colonists would live inside the ring and movement would be analogous to that of a hamster moving within a hamster wheel. The study concludes that shapes such as spheres are extremely inefficient in this regard (providing limited occupiable space), while more ring shaped structures such as the torus or even the dumbbell are much more practical.
In all likelihood, a final design may be a combination of a few of these geometric ideals, or perhaps multiple instances of a smaller geometry -- such as bands of toruses or multiple stacked dumbbells -- rather than one very large torus (a single torus could exceed 5 kilometers in diameter alone in order to accommodate a colony of 10,000 inhabitants and achieve some semblance of "flatness" to the occupants). By using multiple instances of a particular geometry, a more compact and economically feasible ship could be designed while still providing adequate space for the colonists.
The concept of modularity becomes extremely important when discussing the design and construction of a vessel that could be hundreds if not thousands of meters in length. Rather than constructing one large, massive vehicle, it makes considerably more sense to compose it from numerous smaller modules, allowing for economic scalability, systems redundancy, and future additions.
One key concept behind such modularity, however, should be the idea of allowing for controlled design and construction, while permitting some degree of modification by the colonists -- a notion that should span the design gamut from the master planning of the ship, down to the design of individual dwellings and public spaces. Granting the users the ability to modify their environment contributes significantly to fostering healthy mental well being.
Static, immovable spaces subject occupants to an unhealthy monotony, quickly resulting in mental atrophy and discontentment. Furthermore, such rigid constraints would not permit for situational adaptation when colonists must deal with issues arising outside of the anticipated design parameters and ad hoc solutions are necessary.
By developing vessel habitat designs with modularity in mind, several beneficial conditions arise as a result.
As aforementioned, considerable cost savings can be achieved through smaller scale, repetitive construction techniques with tighter quality control. As a significant challenge will be the dissemination of such components into temporary orbit or to a Lagrange point for composite assembly, smaller modules may allow for easier assembly and lower transport cost. Thoughtfully designed living vessels should be constructed in such a manner that colonists aboard the ship may continue to fashion additional 'shells' as needed when expansion is necessary, as they will likely have to rely on easily sourced materials and available processing techniques.
Within a series of interconnected modules, myriad habitat designs and considerations are possible. Dwelling architecture could resemble that found within moderately dense, urban earth environments, with units stacked or configured in multistory condo and townhome arrangements, stepping up to take advantage of available vertical space.
The aim would be to create as strong a sense of 'home ownership' as possible, rather than simply feeling like a permanent guest at a hotel. Although such a society won't rely on cars, the overall scale of the ship is likely to be several kilometers in aggregate length, and some sort of easily accessible transit will likely be required.
Pedestrian streets and open spaces should be provided for colonists to exercise, walk their pets, play soccer, or go for leisurely strolls. Architecturally there would be a variety of styles among the units while still employing modularity, as each "neighborhood" or "block" should have its own character, with colonists encouraged and enabled to make personal modifications and additions. Thoughtful planning would ensure that a variety of vista options and view sheds exist to mitigate feelings of claustrophobia -- framed external views or internal focal points would allow for continuous visual discovery and interest.
At a macro level, spatial diagrammatic studies are essential in determining the best configurations and groupings of residential and commercial pockets, and how they may be interspersed among retail town centers, research centers, agricultural pods, and places of work/education. Individual neighborhoods should develop their own character to encourage diversity throughout the colony.
For example, imagine a medium sized university on earth, where each dormitory is different, the halls are all known for something unique, and it takes years to fully explore the campus. Every effort to promote diversity and 'texture' where possible should be made.
In A Material World
Due in large part to popular culture disseminated over the last century, there exists no shortage of imagery influencing the perception of what interior space aboard a worldship may look like.
Mid-20th century space exploration supplanted into our minds images of utilitarian capsules, barely large enough for their occupants, while television and cinema have provided streamlined impracticality. Advances in technology have provided lasting images of tubular modules interconnected through means of hatches reminiscent of a submarine, with Velcro and whiteness abounding. Rarely explored, however, is the notion of actually trying to provide as many Earth-like comforts as possible within an artificial environment.
On earth, we enjoy the comforts provided by rich organic materials such as wood and stone, in addition to metals. Although the latter material may at first glance seem the most practical aboard a worldship, the former two should not be discredited as they embody a connection with nature. Even if used as a veneer or internal facade, the appearance of warm "home-like" materials will provide users with a sense of comfort and place, while still allowing for less aesthetic, but structurally required materials to be used without jeopardizing the human experience.
While clearly a large amount of space will be required for primary food provisions, the use of vegetation and trees does not have to be contained to just pods of agriculture. Thoughtful design would take advantage of an individual item's multiple functions. For example, agriculture dispersed among places for respite, such as fruit trees at a park, provide food, recreation, CO2 reduction and O2 contributions. By capitalizing on elemental repurposing, significant habitat and financial gains can be attained.
While there is a need for greater research and design studies, the Stanford study certainly encapsulates a plethora of solid ideas and valid data, carefully assembled in a meaningful manner in an effort to serve future design generations. Although great strides in mechanical prowess and propulsion technology are evolving daily, it is imperative to long-term success that equal attention be paid to the evolutionary design processes necessary to ensure that habitat design does not take a back seat.
As various teams of specialists -- ranging from propulsion scientists and material engineers, to urban planners and interior architects -- contribute to the accretion of ideas and design elements, the dream of someday dispatching a community of space explorers on an unprecedented mission in perpetuity becomes even more tangible.