In selecting a baseline configuration, box systems were rejected because they normally involve the duplication of walls and floors and tend to be overly heavy. If metal vapor deposition is developed as a forming technique however, this type of system would become highly desirable. Bearing-panel systems were likewise rejected since they do not allow integration of mechanical subsystems except during erection, and since walls are heavy because they are load bearing. Cable and pneumatic systems were rejected due to their inability to span short distances without special provisions. However, they might be highly desirable because of their flexibility and lightness if a lower gravity environment proves acceptable in the colony.
The system that appears most suitable for use in the colony might involve a light, tubular structural frame (composed of modular column and beams) in combination with walls that are nonload bearing and with prepackaged, integrated mechanical subsystems (such as bathrooms) where needed. This system provides lightweight modularity to a high degree, good spanning capabilities, easily obtainable structural rigidity, and short assembly time since all labor intensive mechanical systems are prefabricated. A schematic (ref. 13) of some possible components of such a system is shown in figure 4-8. Applications of such a system to the colony are many and could be applied to all necessary enclosures with proper adaptation to the various specialized needs of life in space.
Some of the possible materials and components investigated as especially suitable for building in space are illustrated in appendix F. Elements that are light and strong and could be made from materials available in space are favored. The exterior and interior walls and the floor components are built from these materials. The floor components are based on extremely light yet strong elements designed for Skylab.
THE PEOPLE IN THE COLONY
It is not usual to think of human population as something to be designed. Nevertheless the numbers, composition, age and sex distribution, and productivity of the colonists bear importantly on the success of the project and on the creation of a suitable design. The study had to consider who should be the colonists, how many there should be, what skills they must have, and how they should organize and govern themselves. The alternatives are numerous and the grounds for choosing between them not as definite as for the more concrete problems of engineering, but it was possible to make what seem to be reasonable choices based on the goals of having in space permanent communities of sufficient productivity to sustain themselves economically.
Size and Suitability of Population
It is possible in principle to specify a productive task, for example, the manufacture of solar power satellites, and then calculate the number of people necessary to perform it, the number needed to support the primary workers, and the number of dependents. The sum of such numbers does not accurately define the population needed to found a colony since the calculation is complex. Even a casual consideration of what is necessary for a truly closed society would suggest that a colony population be far in excess of any reasonable first effort in space.
A similar approach would bypass the calculation just described and simply copy the population size and distribution of a major productive urban center on Earth. The difficulty, however, is that such communities are quite large, on the order of some hundreds of thousands of people. Moreover, close inspection reveals that human communities on Earth are less productive by labor force measurement standards than what would be needed in at least the early stages of space colonization.
One way to have a colony more productive than Earth communities would be to make the colony a factory, populated only by workers. The colony would then be only a space station, with crews of workers rotated in and out, much as is done on the Alaska pipeline project. Aside from the serious problems of transportation, such an approach does not meet the goal of establishing permanent human communities in space.
In the face of these difficulties a rather arbitrary decision is made to design for a colony of 10,000 with an attempt to bias the population in directions that favored high productivity but does not compromise too badly the goal of setting up a community in which families live and develop in a normal human way. It is also assumed that the completed colony is not an isolated single undertaking, but is a first step in a rapidly developing program to establish many colonies in space.
Ethnic and National Composition
The possible variations in nationality or ethnic composition are in principle very great. The actual composition will depend largely on who sponsors and pays for the colonization. If colonization were undertaken as a joint international project, the composition of the population would surely reflect that fact. On balance, however, it seems reasonable for the purposes of this design to assume that the first space colony will be settled by persons from Western industrialized nations.
Age and Sex Distributions
The initial population of the first colony is projected to grow from a pool of some 2000 construction workers who, in turn, bring immediate family members numbering an additional one to three persons per worker. Selective hiring of construction crew members tends to bias this population toward certain highly desirable skills, and toward the younger ages. In anticipation of the labor needs of the colony and the need to avoid the kinds of burdens represented by large dependent populations, a population is planned with a smaller proportion of old people, children and females than the typical U.S. population. It is a close analog of earlier frontier populations on Earth.
The proposed population is conveniently described in terms of differences from the population of the United States as described in the 1970 Census (ref. 14). These changes are illustrated in figure 4-9 which compares the colony with the composition of a similar sized community on Earth.
Figure 4-8 — Modular construction for inside the habitat. This diagram illustrates the kinds of components which might be used in building the space colony. A. Wall panels, nonstructural, can be any material depending on acoustical, thermal, and stability requirements; B. floor construction light honeycomb panels; C. shades, railings, etc., added in place; D. structural supports — receives frame; E. "roofing" kits — translucent, clear or opaque, of various configurations; F. structural frame — stacks four stories, 1.82 m or 3.64 m X 5.46 m structural bay; G. roof panels — used where tops are intended for walking surfaces; H. ceiling panels — visual and thermal barrier; I. spanning planks or beams; J. beams. Source: Building Blocks Design Potentials & Constraints, Center for Urban Development Research, Cornell Univ., 1971.
<!-- image -->Figure 4-9 — Population distributions of sex, age, and productive effort in the initial colony and in a similar sized community on Earth.
<!-- image -->The sex ratio is about 10 percent higher in favor of males, reflecting both the tendency of construction workers to be male and the expectation that by the time construction begins in space an appreciable fraction of terrestrial construction workers are female. Partly for this last reason and partly because of the anticipated need for labor in the colony, sizable increase in the proportion of married women in the labor force is assumed. Most striking is the substantial shift of the population out of the more dependent ages — from under 20 and over 45 into the 21 to 44 age class.
Export Workers
Productivity of any community is importantly influenced not only by the size of the labor force but also by the share of worker output going for export. Numbers on modern U.S. communities (see, e.g., appendix G) indicate that in our complex society the percentage engaged in export activity is generally less in the larger cities than in the smaller towns. The maximum activity for export seems to be about 70 percent. Without taking into account the peculiarities of life in space, the study group assumes that 61 percent of the workforce, or nearly 44 percent of the population of the initial colony would be producing for export (see fig. 4-9). This percentage declines as the colony grows. Conversely at an early stage in its development when the population is about 4300, the workforce is about 3200, with 2000 producing for export. Appendix G provides the data from which these assumptions are derived.
Social Organization and Governance
The form and development of governance depend strongly on the cultural and political backgrounds of the first colonists. The subject is rich with possibilities ranging from speculative utopian innovations to pragmatic copies of institutions existing on Earth. Among the alternatives easily envisioned are quasimilitary, authoritarian hierarchies, communal organizations like kibbutzim, self-organized popular democracies operating by town meetings, technocratic centralized control, or bureaucratic management similar to that of contemporary large corporations.
It seems most likely that government for the initial colony would be based on types of management familiar in government and industry today. There would be elements of representative democracy, but the organization would surely be bureaucratic, especially as long as there is need for close dependency on Earth. But whatever the forms initially, they must evolve as the colonists develop a sense of community, and it is easy to imagine at least two stages of this evolution.
First there is the start of colonization by some Earth-based corporate or governmental organization. Later, as continued development leads to more and more settlement, the colonists form associations and create governance bodies which reflect rising degrees of community identity, integration and separation of decision-making powers from organizations on Earth. These changes evolve first within a single habitat and then cooperative and governmental relations develop when neighboring habitats and a larger community grow. The rate at which this evolution occurs is uncertain.
LIFE SUPPORT
What do the colonists eat and how do they obtain this food? What do they breathe? How do they deal with the industrial and organic wastes of a human community in space? These questions pose the basic problems to be solved by life support systems. Richness of life and survival from unforeseen catastrophes are enhanced by diversification and redundance of food supplies, energy sources, and systems for environmental control, as well as by variety of architecture, transportation and living arrangements, and these considerations are as important in choosing among alternatives for life support as in making choices among other subsystems.
Food
Food supplies can be obtained from Earth or grown in space or both. Total supply from the Earth has the advantage that the colony would then have no need to build farms and food processing facilities or to devote any of its scarce labor to agriculture. However, for a population of 10,000 the transport costs of resupply from Earth at 1.67 t/yr per person is about $7 billion/yr. The preferred choice is nearly complete production of food in space.
Whatever the mode of production, it must be unusually efficient, thereby requiring advanced agricultural technologies (ref. 15). Direct synthesis of necessary nutrients is one possibility, but such biosynthesis is not yet economically feasible (J. Billingham, NASA/Ames, personal communication).¹ Also, algae culture and consumption have long been envisioned as appropriate for life in space, but upon close inspection seem undesirable because algae are not outstandingly productive plants nor are they attractive to humans (ref. 16). The best choice seems to be a terrestrial type of agriculture based on plants and meat-bearing animals (ref. 17).
This form of agriculture has the advantage of depending on a large variety of plant and animal species with the accompanying improvement in stability of the ecosystem that such diversity contributes (ref. 18). Moreover, plants and animals can be chosen to supply a diet familiar to the prospective colonists, that is, a diet appropriate to a population of North Americans biased in favor of using those plant and animal species with high food yields. Photosynthetic agriculture has a further advantage in that it serves as an important element in regeneration of the habitat's atmosphere by conversion of carbon dioxide and generation of oxygen. It also provides a source of pure water from condensation of humidity produced by transpiration (ref. 19).