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 selfsustainable 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 selfsustainable space settlement [1, 2, 3, 4, 5]. Several previous designs limit the selfsustainability of the settlement to economical and physiological survivability. The expected degree of selfsustainability of a space colony has not been precisely stated. The concepts of social, cultural and scientific selfsustainability have not been yet introduced. These notions are discussed in this chapter.
2. Feasibility analysis of population selfsustainment
The feasibility analysis of a selfsustainable 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 selfsustainability 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 selfsustainable 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 selfsustainable. 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 34 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.
SELFSUSTAINABILITY 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 10’00040’000 would not be able to selfsustain 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 selfsustainable 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 selfsustainable. 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 selfsustainable. 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 selfsustainable and is not acceptable as a longterm 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 XPrize contest.
CONCLUDING ON CONDITIONS
It is feasible that the space settlement selfsustains physiologically and may fulfill its security and social needs, but it is not realistic to think of it as culturally, scientifically and industrially allatonce selfsustainable society. To be able to selfsustain from all points of view, including the above three, the population of the settlement should be in the range 100’0001’000’000. 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 selfsustainment 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 selfsustainment criteria. These include:
· Capability of a population living at a remote area in space to have an internal economy;
· Capability of industrial selfsustainment;
· 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 selfsustainment 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 
Nonagricultural
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 

Nondurable
goods 
5.59 

Food
industry 
23.1 
Out
of nondurable 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 
2.79 
Including defense and Meteor
collision prevention system 
[*]=out of total employed population
The ratios computed in Table I.1 are according to the scientific needs of the settlement. A higher employment rate was considered for education, engineering and some business services (computer and data processing services). Some specific services are included (such as the Meteor collision prevention system). The total number of medical personnel has also been recalculated, according to the colony’s needs.
Figure I.1. Population composition considering employment status. Includes employed persons, retired, children and unemployed students.
Figure I.2. Population composition considering the major activity domains.
COMPUTATION OF SPECIFIC EMPLOYMENT REQUIREMENTS
Media
To satisfy its cultural and communication needs, the settlement will need its own media. The population of the settlement being of 100’000 will afford a local TV studio, radio studio and a local newspaper. A local TV studio has largely the same employment requirements as a radio studio – 30 people minimum. A local newspaper has an employment requirement of 15 people (ten people for the editorial board and five more people for the printing house).
Medical personnel
As people onboard the settlement will live in a relatively isolated environment, with tense deadlines (in R&D, for example) and higher stresses, they will need periodical psychological counseling and examinations. It is simply more difficult to live in a closed environment, relatively far from Earth and with tenser deadlines than living on Earth. People will need to maintain their society as elite, in order to preserve its economical viability. Usual relaxation requirements include parks, restaurants and theatres. Counseling may be a medical requirement. A higher number of psychologists may be required. People will likely need an examination every six months. An examination/counseling session takes on average one hour. Thus per year we will need 2000 hours of counseling/examination sessions per 1000 people.
For the total population of 100’000 200’000 hours of counseling/examination sessions are needed yearly. One year has in average 260 workdays. A usual work shift takes eight hours. Thus, the total work time per year [average] is 2085 hours. We will need approximately 95 psychologists for the entire 100’000 population.
For the total medical personnel, we should take into account that specialists should represent all major fields (ophthalmologists, dentists, pediatricians, family and general practitioners, anesthesiologists, surgeons, audiologists, internists, obstetricians and so on). An emergency medical system must be included. The minimal number of highly qualified medical personnel should be three doctors per field per 10’000 people. Each doctor may be supported by 23 assistants on average and by two more maintenance personnel. Pharmacists are at least 15 per 10’000 people. Thus, the minimal number of medical personnel for the 10’000 population cell is in the order of 165. The minimal employed population in the health care system is 1.75%. The recommended employment in the health sector is of about 4%, after [6].
Defense and security
An asteroid/meteor collision prevention system should be developed for the settlement’s society. This defense system should look for potentially hazardous meteors/asteroids (using a radar system). Large objects on an impact course could be deflected or destroyed using a laser system or other methods.
The settlement should be protected also against any disastrous situation. Highly qualified and trained personnel should be able to deal with any extreme security problem or hazardous situation (such as a fire). These should be the elite defense personnel. The defense sector will cover 2% of the employed population
Basic security needs are ensured by security personnel (0.5% out of total population). These should also be trained as firemen and some as emergency medical personnel.
4. Population growth models
Various models have been proposed in the past in order to express the growth of a specific population. Each model is discussed and analyzed in order to determine which one is best suited for computing the settlement’s population growth.
THE FIBONACCI MODEL
This model does not apply to human populations. It applies to rabbit populations. It is important, as it was the first population growth model.
The model is defined using a linear seconddegree recurrence:
_{}, (1)
where _{} is the population at the moment of time n.
Equation (1) has the general solutions stated in the following expression:
_{},
where _{} and _{} are constants determined from the initial conditions (2), while _{} and _{}are the solutions of the characteristic equation for recurrence (1):
_{}
The initial conditions for this model are:
_{} (2)
We do not insist further on this model, as it does not apply to human population.
EXPONENTIAL GROWTH MODEL (MALTHUSIAN MODEL)
The natural growth model or exponential growth model in its discrete form states:
_{} (3)
where _{} is the initial population, n the moment of time and k the growth rate.
From (3) the model of natural growth is determined in its continuous form:
_{} (4)
Divide expression (4) to the time variation _{} in order to obtain:
_{} (5)
By multiplying (5) with _{} and then dividing the expression with _{} we obtain:
_{} (6)
Equation (6) is the differential growth equation. By integration, the equation states:
_{} (7)
where c is a constant, determined from the initial condition. The initial condition states:
_{} (8)
Change c from expression (8) into equation (7) in order to obtain:
_{} (9)
which is the Natural Growth Model in its continuous form.
An important theorem of natural growth is:
A population following the Natural Growth
Model will double in a constant amount of time, regardless of the initial
population.
To prove the theorem, we first consider two different moments of time, _{} and _{} _{}. _{} is the amount of time in which the population doubles. The following notation is used for further calculus: _{}.
The population doubles in _{} time, stating that:
_{}
_{} (10)
Equation (10) proves that the time in which the population doubles is a constant regardless of the initial population. Notice that this model does not reflect realistic population growth. As will be seen in the next model, other factors influence population growth. This model is widely used for the radioactivity law (in order to model the decay rate of radionuclides population). The decay rate is obtained from equation (6):
_{} (11)
If the decay rate is known for a specific radionuclide population, the _{} coefficient may be determined:
_{} (12)
The _{} coefficient is <0 for radionuclide populations (as it expresses the decay) and is >0 for human populations (as it expresses growth).
However, this model has its limitations. It is applied for determining the decay of radionuclide populations, but for human populations it is just a fair approximation. Notice in Table I.2 that the population does not double at exact intervals. Figure I.3 is based on the world population census for the past century. Notice that significant variations occur in the real model in respect to the exponential growth model. The Malthusian Model is, however, widely used.
Table I.2. World population growth versus time for the period 19001985. Data from [10].
Figure I.3. World population growth for the past century. Notice that the real growth may be approximated with an exponential growth, but significant variations appear in the real model.
The population does not follow exactly the exponential growth, as other factors intervene in growth. For example, if a population grows, its efficiency and selfsustainment capacity will also grow, but up to a limit. The limit is determined from the fact that a population will not have enough food or space to grow indefinitely. These are only some of the natural limiting factors for population growth. In a realistic model, we have to take into account that as the efficiency of the population grows, so does its growth rate.
These factors are taken into account by the Heinz von Foester model.
THE COALITION MODEL (HEINZ VON FOESTER)
We restate the differential growth equation from the Natural Growth Model:
_{}
Notice that _{} is the growth rate. If the growth rate is also dependent with the population growth (and thus timedependent), then we have the following law:
_{} (13)
In (13) h is a constant, _{}. (13) is the von Foester model in its differential form. Notice that if _{} (13) is reduced to the natural growth model. The coefficients _{} are dependent to the development capacity and productivity of a specific society. The values of these coefficients for the settlement population should be determined from direct experimental analysis of a large population’s growth in a closed environment – like a large colony in space. In our numerical applications, we used the growth rates as resulting from US Survey [10].
The continuous form of the von Foester model can be determined from equation (13) by integration:
_{} (14)
where _{} is a constant resulting from the integration. (14) is equivalent to:
_{} (15)
Equation (15) is the continuous form of the von Foester model.
THE LOGISTIC GROWTH MODEL (VERHULST)
The Verhulst model considers that if resources decline in respect to the growth of the population, we have to add to the natural growth model (6) a negative factor proportional to the square of the population number:
_{} (16)
The equation (16) is the continuoustime logistic model. In a different form, it is written as:
_{} (17)
Model expressed in (17) is the classical logistic model, proposed by Verhulst in the 19^{th} century. It has a solution in the form:
_{}.
The equation (18),
_{}, (18)
is the discrete form of equation (17). The recurrent equation (18) has no analytical solution. Its solutions have to be determined numerically. The process in equation (18) may be chaotic.
NUMERICAL APPLICATION FOR US AND WORLD POPULATION GROWTH
Data is taken from various censuses ([13], [14], [15]) and the real population growth is plotted. Predictions are made using the exponential growth model and several logistics models. The results are then compared.
Table I.3. US population growth from 1790 up to 2005. Data for population growth before 2000 from [13], data for 2005 from [14].
Year 
Population 
1790 
3.929 
1800 
5.308 
1810 
7.24 
1820 
9.638 
1830 
12.866 
1840 
17.069 
1850 
23.192 
1860 
31.443 
1870 
38.558 
1880 
50.156 
1890 
62.948 
1900 
75.996 
1910 
91.972 
1920 
105.711 
1930 
122.775 
1940 
131.669 
1950 
150.697 
1960 
179.323 
1970 
203.185 
1980 
226.546 
1990 
248.71 
2005 
295.229 
Figure I.4. US population growth for the period 17901990 according to table I.3.
The exponential growth model for the world population with three different coefficients is shown in table I.4 and the corresponding graph in figure I.5. Data from [14] is also used.
Table I.4. World population growth approximated using the exponential growth model for three different coefficients;
Year 
World population 
Exponential model coefficient k=1.01 
Exponential model coefficient k=1.015 
Exponential model coefficient k=1.0012 
1900 
1608 
1608 
1608 
1608 
1910 
1750 
1776.232 
1866.15 
1811.72 
1920 
1834 
1962.066 
2165.743 
2041.25 
1930 
2070 
2167.341 
2513.433 
2299.86 
1940 
2295 
2394.093 
2916.942 
2591.233 
1950 
2517 
2644.568 
3385.23 
2919.521 
1955 
2780 
2779.468 
3646.854 
3098.948 
1960 
3005 
2921.248 
3928.697 
3289.401 
1965 
3345 
3070.261 
4232.323 
3491.559 
1970 
3707 
3226.875 
4559.414 
3706.141 
1975 
4086 
3391.479 
4911.783 
3933.911 
1980 
4454 
3564.478 
5291.386 
4175.678 
1985 
4850 
3746.302 
5700.325 
4432.305 
2005 
6411 
4571.201 
7677.512 
5626.52 
Figure I.5. Comparison between the actual world population growth and predictions using three different coefficients for the Malthusian model.
Population growth is more accurately predicted using logistic models. A numerical application is given for predicting the US population growth. The logistic models used differ in parameters.
Table I.5. US population and predictions by several logistic models (from H.N. Teodorescu, with permission)
Year 
US population 


1790 
3.929 
3.93 
3.93 
1800 
5.308 
5.03498 
4.98538 
1810 
7.24 
6.446604 
6.320566 
1820 
9.638 
8.247401 
8.007557 
1830 
12.866 
10.54049 
10.13557 
1840 
17.069 
13.4537 
12.81438 
1850 
23.192 
17.14388 
16.1778 
1860 
31.443 
21.80086 
20.38709 
1870 
38.558 
27.65044 
25.63356 
1880 
50.156 
34.95484 
32.1397 
1890 
62.948 
44.00905 
40.1574 
1900 
75.996 
55.13051 
49.96163 
1910 
91.972 
68.6394 
61.83762 
1920 
105.711 
84.82727 
76.05947 
1930 
122.775 
103.9132 
92.85898 
1940 
131.669 
125.9902 
112.3854 
1950 
150.697 
150.9699 
134.6598 
1960 
179.323 
178.538 
159.5319 
1970 
203.185 
208.1383 
186.6509 
1980 
226.546 
238.9974 
215.4626 
1990 
248.71 
270.1962 
245.2409 
2005 
295.229 
315.5481 
289.8963 
2010 

329.846 
304.3585 
2020 

356.6967 
332.0838 
2030 

380.8409 
357.7168 
2040 

402.0345 
380.8409 
2050 

420.2479 
401.2444 
2060 

435.6175 
418.8982 
2070 

448.3888 
433.9159 
2080 

458.866 
446.5079 
2090 

467.371 
456.9386 
2100 

474.2163 
465.4926 
The model used to plot fig. I.4 is the logistic equation solution with parameters chosen, for example
_{} (19)
where t is the time in years, t >1790.
Figure I.4. Actual US population growth and prediction using two logistic models that differ in parameters.
Figure I.4 shows that the logistic model predicts much more accurately population growth than the Malthusian model. Figure I.5 is from [11] and shows predictions for US population growth using all three models.
Figure I.5. Population growth models used in discrete form to approximate the US population. The census data is plotted in order to depict model accuracy. From [11].
NUMERICAL APPLICATION FOR COLONY POPULATION GROWTH
In average in developed countries the population growth is 0,2% per year. This ratio is adopted for colony population prediction using the Malthusian model. The problem is to determine after how many years the colony’s population grows significantly such that extension is needed. The amount of supplementary space required for population extension is computed. The Malthusian model is used just as an example for predicting the colony’s population growth.
The coefficients for the von Foester or Verhulst models are dependent on the development capability of the society. It is thus rather hazardous to approximate them or to take the same values as for the US population growth, as we cannot predict how exactly the settlement’s society will evolve. These should be determined experimentally in at least 40 years after the settlement’s operational period has commenced.
The growth ratio is 0,2%. _{} is the population at a given time, n the time [in years]. _{}is the initial population. The growth model is (natural growth, discrete form):
_{} (20)
The values for population growth versus time have been computed from (20) for various moments of time (0100 [years]). The results are shown in Table I.6.
Table I.6. Population growth over a period of 0 to 100 years after to the construction phase. The time increment is five years. An exponential model is assumed.
Time 
Percentage of initial
population 
Growth [%] 
0 
100 
0 
5 
101.004008 
1.004008008 
10 
102.0180963 
2.018096337 
15 
103.0423662 
3.042366194 
20 
104.0769198 
4.076919802 
25 
105.1218604 
5.121860411 
30 
106.1772923 
6.177292308 
35 
107.2433208 
7.243320825 
40 
108.3200524 
8.320052354 
45 
109.4075944 
9.407594354 
50 
110.5060554 
10.50605536 
55 
111.615545 
11.61554501 
60 
112.736174 
12.73617402 
65 
113.8680542 
13.86805423 
70 
115.0112986 
15.01129862 
75 
116.1660213 
16.16602126 
80 
117.3323374 
17.33233742 
85 
118.5103635 
18.51036348 
90 
119.700217 
19.70021702 
95 
120.9020168 
20.90201679 
100 
122.1158827 
22.11588272 
Notice that in 25 years the population will grow with 5%. In 50 years, the population will grow with 10,5%. We consider necessary to include 10,5% more habitable space in the settlement from its construction phase to ensure that sufficient space is provided for population extension. The settlement should start its structural extension 45 years after to its construction.
5. Conclusions
As no significant emphasis was provided in literature regarding to the social/cultural/technical/industrial/scientific feasibility of a large population living onboard a space colony, I did my best to analyze this problem and to depict its importance. The analysis did not focus only on the economical viability of such a society, but also on the social and cultural aspects that should be satisfied by the colony. An estimate of the minimal population to ensure selfsustainability of the colony in all of these aspects was presented. Based on economical, technological, social, educational and scientific viability, the population repartition regarding employment and activity has been analyzed.
Moreover, we found in past designs scarce or no estimates of population growth for a space colony. Various models have been presented in order to state the importance of correctly determining the population growth of the settlement. Population growth is an important concern – if the amount of additional space required for extension is not precisely determined, the population may run out of space or the society will stall its development. However, I can only make predictions on how the settlement’s population will evolve. The three known population growth models (Malthusian, von Foester, Verhulst) are presented, along with a discussion of their use for space applications.
I did my best to pinpoint these problems, which are vital for the existence of any modern society.
FURTHER WORK
There is a degree of uncertainty in predicting the population growth of a space colony. If a better model than the Malthusian is used, experimental data are required. The relationship growthdevelopment and growthresource depletion has to be analyzed for a large population in a closed environment (such as the space colony). We cannot make predictions based on the coefficients determined for the US population or for other countries. The conditions differ – and the state of art does not present any analysis with large populations in closed environments. This lack of knowledge hinders predictions. Experimental data will have to be gathered based on, for example, the development/growth ratio for the first space colony. Until experimental data on this topic is available, our predictions will remain at the state of crude approximations.
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