Chapter 1

POPULATION DESIGN

1. Introduction

I propose the concept of population design and analyze the conditions for population design. Population design refers to the conditions the population has to satisfy in order to become self-sustainable from the physiological, economical, educational, cultural and scientific point of view. Beyond economic viability, several other criteria should be satisfied for the overall viability, including several conditions for the population. Conditions are not limited to economical viability.

In the second section of this chapter, I deal with the main conditions for the population design. The third part deals with the population composition and statistics. The fourth part deals with population growth models.

STATE OF THE ART

The settlement’s population may be evaluated differently in respect to its autonomy and to what it is expected to produce. In previous designs, like [1], [2], [3], [4] scarce or not entirely realistic designs have been proposed. For example, in our own past project ([2]), a scarce model was presented, as only the initial population structure has been analyzed (the population during the construction phase). The design [1] presented a population growth a bit too optimistic. Some designs focused only on the physiological, psychological and recreational needs of a society, rather than on its industrial needs ([3], [4]). Previous designs proposed as a solution to population growth just to provide extra space and to bring initially a lower population than the total settlement capacity ([4]), but have only approximated the required extra space. Many designs focused on settlement construction and life support and did not treat the actual population repartition regarding activity domains ([2], [4], [5]). We assessed these conditions and did our best to analyze all of them in detail, as they are of vital importance for the social organization of a space colony. Different population growth models have been analyzed. A proposal for how much space would be needed for settlement extension has been given.

Various designs proposed a self-sustainable space settlement [1, 2, 3, 4, 5]. Several previous designs limit the self-sustainability of the settlement to economical and physiological survivability. The expected degree of self-sustainability of a space colony has not been precisely stated. The concepts of social, cultural and scientific self-sustainability have not been yet introduced. These notions are discussed in this chapter.

2. Feasibility analysis of population self-sustainment

The feasibility analysis of a self-sustainable space settlement from social, economical and industrial points of view has been ignored in past designs. Also, the population requirements that have to be satisfied in order to ensure self-sustainability have not been thoroughly analyzed in past designs.

The aim of the feasibility analysis is to pinpoint the requirements in order to build a space colony in the near future (<60 years).

A self-sustainable space station must fulfill all of the following fundamental needs of people living in space:

· Basic biological requirements;

· Physiological needs

- atmosphere;

- water;

- food;

- thermal comfort;

- the need to live in a clean, proper environment;

- health needs.

· The need for security;

· The need for social relationships, for communication and for relaxing environments;

· The need for culture and for scientific development;

· Economical survivability.

These needs should be fulfilled by the population onboard the space settlement if it is fully self-sustainable. This means that the people onboard will be able to provide themselves with food, and construction materials, to develop culture, media, and industry, to have economical exchanges and to develop social relationships. The settlement society will need to progress in scientific and cultural fields at least at the same rate as the population on Earth in order to become economically viable and competitive.

BASIC BIOLOGIC REQUIREMENTS

We first deal with the minimal permanent population on the settlement, as determined by biologic requirements. If the population would be lower than 1000, then in 3-4 generations hereditary diseases will have a significant impact on the colony. This is according to Gregor Mendel’s theory and has been experimentally proven with various animal populations (such as tigers). The biologically viable minimal population should be at least 1000 strong.

SELF-SUSTAINABILITY REQUIREMENTS

Consider the settlement’s community as having autonomy from a cultural or scientific point of view. A population of 10’000 (as given in many past designs without significant justification [3], [4], including our own design [2]) cannot sustain a complete university (with all faculties, including Medicine and Law), a complete industry and education centers and schools in which to train people for all the activities a developed society needs. A population in the range of 10’000-40’000 would not be able to self-sustain educationally, culturally and scientifically, because it could not include a complete university. A complete university would simply not justify the cost for a population under 100’000 (as there would not be sufficient students for all faculties – economically speaking at least 10’000 students per university, according to standards on the Earth). Consider here a university preparing Ph.D. and Bachelor students in specific fields of importance for space exploration and engineering, such as: Aerospace engineering, Astrobiology, Space Medicine, Space Geology, Electronics (super conductibility, semiconductors), Astronomy.

The too small settlements would have to “import” specialists – doctors, lawyers and researchers on narrow fields in order to survive economically and technologically. To train all these specialists on the settlement would require much higher costs than to bring them from Earth, as a university that has faculties with fewer than 100 students per year is not profitable. In fact, operating a complete faculty for less than 100 students per year does not justify the costs.

THE NEED FOR CULTURE AND FOR SCIENTIFIC DEVELOPMENT

In order to become self-sustainable from a cultural point of view, the settlement would require artists, writers, philosophers and its own media. Without a university to train, inspire and learn people in all these fields, the station would simply have to “import” them as well.

A society will not become good enough in any field without competitive spirit. If people are not constantly in competition with others in their field, they would not have enough motivation to complete their work at the highest level. Researchers, artists, even sellers and manufacturers must be maintained in a competitive environment. 10’000, 40’000, even 100’000 people are not enough to ensure competition in all activity fields. I consider that competitive spirit is one of the basic mechanisms of modern society. Without it, a society may not excel. Looking at it otherwise is not realistic.

By analyzing the economical/industrial/cultural needs of a town with a population under 100’000, we find that it is not self-sustainable. It is not autonomous either from a scientific/cultural point of view (it has no or just a small university, that does not cover all fields) and either from agricultural/industrial points of view. Such a society cannot produce everything, because there are simply not enough people to support all industrial or research fields. This means that it cannot become industrially self-sustainable. The space settlement is just like a small town in space – only that it is rather isolated and it needs to produce by itself everything a modern society requires to survive.

ECONOMICAL SURVIVABILITY

There is no state having sufficient raw materials to sustain itself in all industrial fields. The settlement may obtain the raw materials required for its industry by extracting them from the Moon/asteroids. It may request periodically shipments of a specific raw material that cannot be extracted in sufficient amounts from the Moon/asteroids – but that would mean it is not self-sustainable and is not acceptable as a long-term solution.

The settlement must have an operational industry and may “import” during the construction period from Earth only the tools/materials that are too expensive to be produced in space. The settlement should offer – during its operational period – research, the possibility to train specialists in space in very narrow research fields, the possibility to launch cheaply and with a higher frequency space missions and the possibility of developing a community interested in space studies. Having the possibility to build and send spacecraft directly from space would mean sparing large quantities of fuel. It would turn both manned and unmanned space missions more affordable and frequent. Another advantage is commercial space tourism, that has been recently proven possible by the results of the X-Prize contest.

CONCLUDING ON CONDITIONS

It is feasible that the space settlement self-sustains physiologically and may fulfill its security and social needs, but it is not realistic to think of it as culturally, scientifically and industrially all-at-once self-sustainable society. To be able to self-sustain from all points of view, including the above three, the population of the settlement should be in the range 100’000-1’000’000. Even so, after completion it would still require a source of raw materials (the lunar extraction facility) for its aerospace industry, so it would not be fully independent from a resource point of view. In order to ensure self-sustainment of the settlement, we propose its population of at least 100’000.

3. Population composition and statistics

The population composition is determined based on economical viability and self-sustainment criteria. These include:

· Capability of a population living at a remote area in space to have an internal economy;

· Capability of industrial self-sustainment;

· Viability of research and education.

The space settlement’s society should not have a significantly different population composition than a highly developed society on Earth. The colony’s population should cover all activity fields in order to have its own internal economy. It has to produce goods for internal use and for export (satellites, spacecraft, robotics for unmanned space missions and so on). It must have its own administration, government services, and social, security maintenance services in order to cover all the needs of a modern society. All industries required for manufacturing modern society goods should also be represented in order to ensure economical viability.

There are two population compositions to consider. The first on is for the construction phase of the settlement. It has been presented in numerous past designs, including our own ([2]) and it is discussed in detail in a different approach (in relation to supplies needs and project timeline) in Chapter II.

The population composition for the operational phase of the settlement is relevant for the analysis, as it reflects the capability of self-sustainment of an orbital space colony.

In this phase, the employed population is considered as in the US Survey [6] and is of 64.1%. The rest of 35.9% is comprised of students (5.5%), children (15.3%) and retired persons (15.1%). Notice that the students’ ratio may rise up to 10%, considering that many may be employed in research while completing their Bachelor or Ph.D. degrees. Unemployment should be maintained below 0.1%, as almost everyone will be needed.

The population repartition on activity fields is presented in Table I.1 and in Fig. I.1 and I.2. The industry, agriculture and services activities are represented with their subsections. There are two types of ratios presented: per activity domain and per occupation. The categories cover largely the development needs of a modern society.

Table I.1. Population repartition per occupation. Based on the US Employment survey 2000 [6].

Occupation	Percentage	Notes
Ratios per activity domain	-
Civilian labor force	64.1
Agriculture	2.51	Out of total employed population
Non-agricultural industry	97.49	Out of employed population
Ratios per occupation	-	Out of total labor force
Managerial and professional specialty	30.61
Technical, sales & administrative support	28.8
Service occupations	13.34
Precision production, craft and repairs	10.88
Operators, laborers and fabricators	13.86
Farming	2.51
Per activity (excluding agriculture)	-
Industry	97.49
Goods manufacturing	19.32	Out of which:
Mining	0.41	Provided by the lunar extraction facility
Construction	5.01
Manufacturing	13.9
Durable goods	8.31
Non-durable goods	5.59
Food industry	23.1	Out of non-durable goods industry employment
Food industry	1.29	Out of total employed population [*]
Recycling industry	3	[*]
Services (1) - producing	75.17	[*]
Transportation	3.35	[*]
Communications & public utilities	1.81	[*]
Wholesale trades	5.21	[*]
Retail trades	17.14	[*]
Finance & insurance	5.86	[*]
Services (2)	26.51	[*], part of the services employed population (1)
Health services	4	[*]
Engineering services	7	Including space engineering, [*]
Recreation services	1.2	Including parks’ and theatres’ management and maintenance, [*]
Business services	6.8	[*]
Computer and data processing services	45	Percentage out of the business services’ employed population
Social services	2	Residential care, child care etc. [*]
Settlement maintenance services	3
Security services	0.5
Tourism	1.51	Hotel personnel, guides and so on; necessary for development of space tourism [*]
Miscellaneous	0.5	[*]
Government services	15.29	[*]
Education services	12.5
Other government services