6. Building the Colony and Making It Prosper

For the functioning system described in the previous chapter to become a reality much preparatory work must take place to fill in the gaps in current knowledge. Initial efforts toward space colonization begin on Earth, move into low Earth orbit (LEO) and continue later to the lunar surface, the site of the mass catcher (L2), and finally to the site of the colony (L5).

Critical gaps in present knowledge and experience, such as physiological limitations of a general population and dynamics of closed ecological systems, require extensive basic research before space colonies can be established. Parallel engineering efforts are also needed to develop suitable techniques, processes, and materials for colonization of space. Pilot plants for extraction of materials, for fabrication in space, and for power production are necessary to provide design and operations experience. Finally, transportation systems, in particular the mass launcher and catcher, and the rotary pellet launcher which are necessary for transporting lunar ore to L5, must be developed early in the space colonization effort.

This chapter describes the projected preparations, operations, schedules, and costs to establish a permanent colony in space. While not optimized with respect to any criterion, they have been conservatively developed to demonstrate feasibility. The sequential activities needed for space colonization and the costs for such a program are summarized in figures 6-1 and 6-2.

Also included in this chapter is a discussion of the satellite solar power stations (SSPS's) as a potential economic justification for space colonization. If production of SSPS's were to become the central activity of space colonists, several modifications of the system logistics would be likely.

PREPARATORY WORK

Activities on Earth

Systems not requiring zero-g can be developed in pilot plants on Earth. These include systems for materials extraction and fabrication, power generation, transportation, and habitation. Techniques for processing lunar soil into structural materials are especially critical for the colonization program since they differ significantly from those currently used on Earth (see chapter 4, appendix I and appendix J). Those processes which require vacuum can be tested on a small scale on Earth. In addition, many of the large subsystems, while ultimately dependent upon the features of the locale in space, may be studied or partially developed on Earth. For example, a large facility or manufacturing plant may use lighter structures and different heat radiators in space; nevertheless, its internal processes can be studied in detail on Earth. These preliminary RDDT&E efforts are critical milestones for most major elements of space colonization.

Both nuclear and solar power sources of large scale must be developed, even though solar electric power is generally preferred since a specific plant mass of 14t/MW is estimated for solar plants as compared to 45 t/MW for unshielded nuclear generators. Nuclear power is planned for the station in LEO and for the lunar base so that continuous power can be supplied during frequent or prolonged periods of being in shadow.

Two basic transportation systems must be developed; one to lift large and massive payloads, the other to transport lunar ore to L5. The first system includes a heavy lift launch vehicle (HLLV) capable of lifting 150 t to LEO; an interorbital transfer vehicle (IOTV) with a 300 t payload for missions from LEO to high orbits; e.g., to L2, L5, or to lunar parking orbit; and a lunar landing vehicle (LLV) with a 150 t payload capacity. These vehicles can be developed using the technology developed for the space shuttle. Development of the lunar mass accelerator, the mass catcher at L2, and the interlibration transfer vehicle (ILTV) is less certain but is still expected to use to use current technology.Major research, as opposed to the above technological development, is required on physiological effects and ecological closure. The physiological effects that are amenable to research on Earth include long-term exposure to reduced total atmospheric pressure, to reduced pressures of certain gases, and effects of rotation on vestibular function. Research into questions of ecological closure is vital to the long-range colonization of space. The mix and quantity of flora and fauna needed to maintain closure or partial closure together with humans must be quantified. Moreover, research into intensive agricultural techniques is important in the colony's efforts to provide its own food. Particular attention must be directed to microbial ecology; the varieties, amounts, and interactions of bacteria and other microbes needed for healthy agriculture, animals, and people, are today imperfectly understood.

Activities at LEO

Pilot plants for materials extraction and fabrication, techniques for materials assembly, solar and nuclear power generation systems, the mass catcher, the ILTV and IOTV, and the habitats are all tested in LEO which provides vacuum and zero-g with relatively rapid access from Earth Research on physiological effects of rotation and reduced gravity is conducted there also.

Activities on the Moon

Preliminary efforts on the surface of the Moon are minimal because the lunar systems can be evaluated and tested near Earth. Moreover, only limited lunar exploration is required (though more may be desirable) since undifferentiated lunar soil supplies the colony with sufficient minerals.

MATERIALS AND SUPPLIES

Fabrication on Earth

Low Earth orbit (LEO) serves as a vital point in the construction and supply of the first space colony. There, a space station consisting of a crew quarters, a construction shack, and a supply depot is assembled from materials made on Earth Additional materials are then launched from Earth to LEO for assembly of the lunar base. They include a nuclear power station, a mass launcher and auxiliary equipment, mining equipment, crew quarters, and maintenance equipment. Also launched is equipment for L2, the mass catchers and the interlibration transfer vehicle (ILTV). The construction shack, the solar power station and the supplies and facilities used in materials extraction and fabrication are launched to LEO for transfer to L5.

Raw Materials from the Moon

Lunar mining operations proceed as described in chapter 5 . Oxygen is an important by-product of the refining of lunar materials at L5. It can be used there as rocket propellant immediately (resulting in a significant reduction in costs of transportation) or can be stored for later use in the atmosphere of the space colony and in its water.

Full use of all of the mass obtained from the Moon is assured by the manufacture of metals, glass, and soil, and by the use of ore and the slag in the cosmic ray shield.

Raw Materials from the Earth

The completed habitat must be outfitted with supplies and raw materials which are available only from the Earth, including highly specialized equipment and personal belongings of the immigrants to the colony. The atmosphere, water, and chemical systems also require raw materials from Earth; mostly hydrogen, carbon, and nitrogen which are not present in lunar ore. The initial agricultural biomass must be transported from the Earth to complete the outfitting of the habitat. From the time when immigration of colonists begins, only the resupply and new materials not available from the Moon are required from the Earth.

TRANSPORTATION AND CONSTRUCTION

Initially all of the supplied materials must be sent from Earth to LEO for transshipment to the point of activity. As operations begin at L5 raw materials must be sent there from the surface of the Moon so that metals can be extracted and the construction of the colony can start.

Transshipment and Assembly in LEO

After the effort of research, development, demonstration, testing and evaluation there is a LEO station with pilot plants for processing materials and for producing nuclear and solar power. Because of the volume and weight limitations of HLLV payload capacity, large items are launched in subunits to be assembled in space. The payload capacity of the IOTV nominally equals that of two HLLV's, but in space neither volumes nor acceleration forces limit the configuration. Assembly tasks at LEO range from repackaging the mass launcher to setting up the complete solar power stations.

A propellant depot must also be established at LEO for use by the IOTV. When this additional propellant is taken into consideration, the mass which must be brought from Earth to LEO is roughly 4 times the payload delivered to L5 and 8 times the payload delivered to L2 or to the lunar surface. However, with the eventual availability of oxygen for rocket propellant as a by-product of refining at L5 the mass which must be brought to LEO becomes approximately twice the payload to L5 and 3.3 times the payload to L2 or to the lunar surface (Austin, G., Marshall Space Flight Center, Alabama, personal communication, Aug. 15, 1975). These factors include return of transportation hardware to its point of origin following each mission.

Lunar Operations

Portions of the lunar base and the propellants for the lunar landing vehicle (LLV) are carried by the IOTV to a lunar parking orbit from which the LLV's ferry material to the lunar surface. As shipments arrive there, an assembly crew successively assembles the power plant, an underground habitat, the lunar soil scoop, and the mass launcher. Two separate nuclear power systems and 2 mass launchers are used to achieve the reliability needed. Their construction is timed to provide substantial operational experience with the first system before a second system is completed. The lunar base also includes a repair shop and a supply of spare parts fortimely preventive maintenance and repairs.

Build-up at L5

The construction shack and the first power plant are delivered to L5 by the IOTV and are assembled by the construction crew. Thereafter, the materials extraction system and the fabrication system are constructed and made operational. Any lunar material received before the processing facility is completed is simply stockpiled.

ESTIMATING COSTS AND TIME

The subsystems, materials, supplies, and operations required for the build-up of the colony system have been outlined in the previous sections. It now remains to schedule the sequencing and timing of the events, and to determine the costs involved with this build-up. The scheduling and costing activities are interdependent.

System Considerations and Constraints

The scheduling and costing presented here are for the establishment of the baseline colony system described in chapter 5 through the completion and population of one habitat.

To allow ample lead time consistent with other large scale projects, the colony's development is scheduled with a gradual build-up of effort and with minimal fluctuations from year to year. Alternative strategies by which costs or project duration may be minimized are outlined briefly in appendix A. In general these results indicate that short durations are accompanied by large system costs. If interest costs are included, there is some minimum cost strategy. However, no optimization is attempted on the schedule presented here.

Automation is included only to the extent that it is now practiced in the industries involved. Bootstrapping (the use of small systems to build larger systems which, in turn, are used to build still larger systems) is not used in the cost estimate for the colony development, with the exception that pilot plants serve mainly to gain design and operational experience. The factors of additional time and added complexity of increased construction in space both caused the rejection of extensive bootstrapping.

Methods Used for Estimation

The scheduling and costing of a space colony require estimation of labor, size, and cost. First, labor: the personnel required in space for each major step of colonization is estimated from a composite of similar elementary tasks performed on Earth but derated or increased by the effects of vacuum and weightlessness. The methodology for estimating labor requirements is described in appendix D of chapter 5; the major results are summarized in table 6-1.

TABLE 6-1 (gif format)

TABLE 6-1.- PERSONNEL REQUIREMENTS

	Number of people	Resupply,* t/yr	Time period,** yr	Rotation, people/yr	Tasks
LEO station	200	330	5-14	400	Physiological testing - rotation, gravity; pilot plant operations andtesting; assembly systems for L5 and Moon depot fuel
LEO station	100 (+ 100 transient)	250	15-25	200	Way station Supply transshipment
Lunar base	300	500	10-14	300	Assemble lunar systems
L5 construction station:	100 2270	167 3784	9-11 12-18	100 2270	Set up L5 site Build shell and 60% shield
L5 colony	10,000			100	Complete interior and shield Live and work
Inter-librational transfer vehicle	10	-	11-25	-	Crew for transfer between L2 and L5

Next, sizes: the main items to be sized include habitats, vehicle fleets, and resupply and mass flow rates. The L5 construction station and the LEO station are nominally 5 t/person with 7 t/person for the more permanent Moon base. The number of vehicles is twice that required for minimum turnaround time. Annual supply rates during construction are set at 1.7 t/person, which includes food, water, gases, and expendables. After the colony is available for habitation, the annual supply rateis reduced over the 4yr colony build-up to an estimated 0.1 t/person.

The mass flow rate from the Moon is sized to complete the shield in 10 yr (1.2 X 10^6 t/yr). The materials extraction and fabrication plants are sized by the completion of the colony's shell in 6 years (9 X I0^4 t/yr). Plant output is assumed (on the basis of an average of terrestrial industries) to be approximately 8.3 plant masses per year. Each power source is sized proportional to its respective power user.

These estimates for the transportation system, the mass and energy systems, and for the habitats are shown in tables 6-2, 6-3, and 6-4, respectively.

TABLE 6-2 (gif format)

TABLE 6-3 (gif format)

TABLE 6-3.- MASS AND ENERGY SYSTEMS - SIZE AND COST

	Output size	Specific mass	Total mass, t	Time period, yr	R&D TFU* $10^9	Number of units	Unit cost, $10^9
LEO Nuclear power pilot plant Solar power pilot plant Pilot materials plant	10 MW 20 MW 2500 t/yr of Al	45 t/MW** 14 t/MW**	450 280(a) 300	6-25 6-25 7-25	2.3 1.4 1.5
L5 Solar power plant 1 2 3 4 5 Materialsplant	20 MW 50 MW 50 MW 50 MW 50 MW 90,000 t/yr of Al	14 t/MW** 14 t/MW** 14 t/MW** 14 t/MW** 14 t/MW**	280 700 10800	9-25 (from LEO) 12-25	-	4 1	0.4(b) 5.4(b)
Mass Transport Lunar Surface to L2 to L5 Nuclear power plant 1 2	120 MW 120 MW	45 t/MW** 45 t/MW**	5400 5400			2	2.7(b)
Mass launcher 1 2	5X10^5 t/yr 5X10^5 t/yr		2750 2750	12-25 14-25	5.0(c)	1	1.4(b)
Mass catcher 1 2 3 4	2.5X10^5 t/yr 2.5X10^5 t/yr 2.5X10^5 t/yr 2.5X10^5 t/yr		340 340 340 340	11-25 13-25 13-25 13-25		3	0.2(b)
Interlibration transfer vehicle (ILTV) 1 (and crew module)2	5X10^5 t/yr 5X10^5 t/yr		400 400	11-25 11-25	2.0	1	0,2(b)

TABLE 6-4 (gif format)

Finally, cost estimates are required for three categories of expenses - research and development through the first unit, purchase price of additional units, and transportation costs. A precise costing effort for the first two items is prohibitively complicated. However, previous space projects have shown that research and development costs vary from $1000 to $20,000 per kg; Apollo was $14,000/kg. In this study $5000/kg is used. Purchase prices are assumed to be $500/kg which is consistent with other large-scale systems. Transportation costs, primarily launch and propellant costs and exclusive of vehicle costs, are based upon a manned payload of 30 people in each shuttle and an unmanned payload of 150 t per HLLV leading to $4.4 X 10^5 per person and $2 X 10^5 per tonne delivered to LEO. Outward beyond LEO, costs depend upon destination. They decrease with increased availability of oxygen in space from processing of lunar material.

These data are summarized in tables 6-2, 6-3, and 6-4 along with the size data. All costs are expressed on 1975 dollars.

Schedule

Scheduling of the colony build-up requires special attention to several key elements of the system; these include the habitats, the lunar nuclear power station, the lunar ore transportation system, the L5 materials processing plant, the transportation costs, and the productivity of the L5 work force.

Very simply, these factors interact in the following manner. Physiologically adequate crew quarters must be developed before any extraterrestrial activities can take place. Thereafter, lunar construction and mining can proceed only with the availability of the lunar nuclear power station. The shipment of lunar ore to L5 requires that the mass launcher/catcher system be operational. Construction activities which use materials obtained from lunar ore depend crucially upon the development of materials extraction and fabrication techniques and upon the completion of the L5 processing facility. Reduced transportation costs are possible as soon as oxygen in space is available as a by-product of the materials processing facility at L5. Finally, the necessary work force which best matches the processing plant output, the desired rate of construction, and the available crew quarters requires careful consideration of the productivity of space workers.

These factors lead to the mission timetable which is summarized in figure 6-1. In brief, the schedule provides for 5 yr research on Earth, 3 to 5 yr for development and testing in orbit near Earth, 5 yr to build up operations on the Moon and at L5, 6 yr for habitat construction, and a final 4 yr for completion of the shield and the immigration of the colonists. The overall schedule projects a 22 yr completion of the colony from the start of the project. Specific details of this schedule for the space colony are given in the tables listed below:

• Table 6-5 (gif format)
• Table 6-5 - Concluded (gif format)
• Table 6-6 (gif format)
• Table6-7 (gif format)

TABLE 6-5.- SCHEDULE OF TASKS

Task	Mass t	Manpower, persons	Cost, $10^6	Years after Go Ahead   1   2   3   4   5   6   7   8   9 10 11 12 13 14 15 16 17 |    |    |    |    |    |    |    |    |    |    |    |    |    |    |    |    |
RESEARCH Closed ecology Physiological effects Material science	--- --- ---	400 200 100	1000 500 150	E* E O*  E
DEVELOPMENT THROUGH FIRST UNIT Pilot plants Solar power (20 MW @ 14 t/MW) Nuclear power (10 MW @ 45 t/MW) Materials processing (7.0 t/day)   Transportation systems Heavy lift launch vehicle Interorbit transfer vehicle Lunar lander   Mass system Mass launcher Mass catcher Interlibrational transfer vehicle   Habitats LEO station (5 t/person) Moon station (7 t/person) L5 station (5 t/person) Crew transport module A Crew transport module B	280   450   300         (150)(a) (300) (150)     2750 340 400       1000 2100 11350 9 63	10       200 300 2270 10 100	1400**   2250**   1500**         300(b) 400(b) 1700(b)     5000** 1700** 2000**       5000** 1100(c) 5700(c) 300(b) 200(b)	E O L*>>***   E O >>     E O >>         E >>  E O >> E O M*>>     E O M >> E    O  L2 >> E  O    L2 >>       E O >> E O M >> E O L >> E O >> E O >>
PRODUCTION Solar power plant 1 (50 MW) Solar power plant 2 (50 MW) Solar power plant 3 (50 MW) Solar power plant 4 (50 MW) Nuclear power plant 1 (120 MW) Nuclear power plant 2 (120 MW) Materials plant (Fab. & Ext.) Heavy lift launch vehicle 1 vehicle 2 vehicle 3 vehicle 4 vehicle 5 Space shuttle 1 Space shuttle 2 Space shuttle 3 Interorbit transfer vehicle 2-4 vehicle 5-9 Lunar lander 2-4 Mass launcher 2 Mass catcher 2-4 Interlibration transfer vehicle 2	700 700 700 700   5400 5400   10800     (150) (150) (150) (150) (150)   (30) (30) (30)     (300) (300)   (150)   2750   340     400	--- --- --- ---   --- ---   ---                 (30) (30) (30)     (450) (450)   (220)             (10)	350 350 350 350   2700 2700   5400     80 80 80 80 80   30 30 30     30X3 30X5   30X3   1400   20X3     20	E O L >> E O L >> E O L >> E O M >>         E O M >> E O M >>           E O L >>           E>>       E>>       E>>       E>>       E>>   E>>       E>>       E>>           E O >>           E O >>             E O M>>                 E O M>>                     E O L2>>                             E O L2>>

*E indicates effort on Earth, O in Earth orbit, M on the Moon, L andL5, L2 at L2.
**Research and development costs are $5X10^6 /t.
***>> denotes the time at which the system becomes operational.
(a)( ) indicates masses which are payloads.
(b)NASA estimates.
(c)Construction cost is $0.5X10^6 /t after experience gained at LEO.

TABLE 6-6.- LABOR SCHEDULE

Years after Go Ahead:

1     2     3     4     5     6     7     8     9     10     11     12     13     14     15     16     17     18     19     20     21     22

TASK Manpower, persons LEO Lunar L5   Resupply, t/yr LEO Lunar L5   Crew roation, persons/yr LEO Lunar L5

200 100                                                  300 150                                      100 2270   4K*   6K   8K   10K                           330 250                                                  500 250                                      167 3784 4200 1000                             400 200                                                  300 75                                      200 100 270 100

*K denotes 1000.

Cost Totals

The task, labor, and payload schedules of these tables are combined with the cost data of tables 6-2 through 6-4 to provide a schedule of costs.

• Table 6-2
• Table 6-3
• Table 6-4

TABLE 6-8 (gif format)

PRODUCTION OF ENERGY IN SPACE AS A
POTENTIAL ECONOMIC JUSTIFICATION FOR
SPACE COLONIZATION

Beyond the Initial Cost Estimate

Costs can be reduced in several ways. Second and later colonies affect total costs, and space colonies have the ability to repay Earth for their initial and operating costs by supplying energy from space. Most of the repayment takes place after the first colony is finished and operating; in fact, the time horizon of the program has to be extended to 70 years. However, such an extension introduces cost uncertainties and suggests changes in the system that would be likely to increase its economic productivity.

Potential for Optimization Based on SSPS Production

A modified sequence to establishing colonies in space is to build several construction shacks first, and then begin building SSPS's and colonies at the same time. Additional workers (above the 4400 housed in the colony) should be housed in construction shacks. Shacks are more quickly built and cost less than colonies but have higher recurring costsof wages, crew rotation from L5 to Earth, and resupply. Colonies have less total cost; that is, initial and recurring costs taken together. As production activities expand, more lunar materials are needed until the capacity of the initial mass launching system is exceeded. To move more material from the Moon will require more power there. Rather than add another nuclear station, an SSPS in lunar synchronous orbit should be considered since nuclear stations are probably cost effective on the Moon only before SSPS's are built in space.

Incorporation of these changes modifies the baseline mission timetable of space colonization operations after year 12, by building additional construction shacks and a lunar SSPS at L5. Although start of construction of the first colony is delayed 3 years (see table 6-5), the colony is still completed by year 22.

The labor force in space also changes from the baseline system; it is smaller through years 12 to 14 and larger afterwards than that given in table 6-1. The initial construction shack houses only 500 people until year 15 when capacity is increased to 2000. By year 14, 3200 workers are needed, by year 15, 5389. No more construction shacks are required after year 15. New cost estimates reflecting these changes are given in column 3 of table 6-9.

TABLE 6-9 (gif format)

TABLE 6-9. - ADJUSTMENTS IN BILLIONS OF 1975 DOLLARS TO THE COSTS GIVEN IN FIGURE 6-2(a)

(1)(b) Year of program	(2) Figure 6-2 costs	(3) Construction shack adjustments	(4) Lunar expansion & lunar SSPS power costs	(5) Transportation adjustments
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22	2.8 3.7 6.0 6.7 7.8 7.1 7.6 11.8 16.2 16.0 18.4 13.8 9.0 9.4 6.8 7.3 7.0 7.0 6.6 7.1 7.1 7.1	-0.9 -2.2 -3.3 -3.3     2.54 1.14 2.07	2.29 1.47 1.47 8.96 8.96	1.3 -4.5

(a) Cost of SSPS's which are built after year 14 and costs of second and later colonies are not included in this table. All costs given in this chapter include a 20 percent surcharge in miscellaneous items and administration.

(b) Indicates columnar numbers referred to in text.

Profitable commercial production of terrestrial SSPS's at L5 would not begin until year 22, although 9 demonstration units, each full scale, would be completed to prove the system during the previous 6 years.

Simultaneously with the SSPS demonstration, a second-generation shuttle system needs to be developed with lower operating costs than the current shuttle. The second-generation system would be justified by the increased traffic into space needed in a space colonization program. As an added benefit, the new shuttle could use propellants that would not pollute the Earth's atmosphere. The effect on costs of one candidate for a second-generation shuttle is shown in column 5 of table 6-9. (See also appendix C.)

Schedule, Costs, and Benefits of SSPS and of Additional Colonies

The U.S. market for electrical energy from space is assumed to be equal to the need for new plants because of growth in consumption and obsolescence of existing plants. The foreign market is assumed to be half of the U.S. market; that is, the same proportionately as fornuclear plants (ref. 1). Uncertainties in new technology delay its acceptance so that markets have to be penetrated. Ten years are assumed for full penetration of the electricity market by SSPS, which may be optimistic based upon current experience with nuclear power.

The market size is assumed to increase 5 percent per year, consistent with the intensive electrification scenario of the Energy Research and Development Administration (ref. 2). Figure 6-3 gives the number of 10GW capacity SSPS's needed each year to meet the terrestrial demand and the number of them actually transmitting energy (based on the assumption that each has a lifetime of 30 yr and begins to deliver power as soon as it is built in space).

Figure 6-4 shows the growth of the number of people and colonies in space if the only aim is to produce electricity for Earth Other additional scientific or industrial activities in space would require larger populations.

Figure 6-5 shows production costs for SSPS's and colonies, and the benefits from electricity generated to terrestrial-based Americans. The economic advantage of space operations would be improved if benefits to foreign nationals from lower electricity costs, and to colonists, are included in the analysis.

An international organization to fund the colonization program would bring even greater benefits to terrestrial Americans as discussed later. But even an American funded program would produce sufficient benefits, based on revenue obtained from sale of electricity and lower price of the electricity to the consumer. The costs for electricity (ref. 3) are discussed in appendix E. A competitive cost for space-derived electricity is 14.1 mils based on the assumption that the most economically produced terrestrial electricity (from nuclear plants) will be 14.1 mils during the period under consideration. It is assumed that electric power consumption will not increase with price decreases and that all nations will be charged the same price.

Cash Flow and Other Results

A summary of cash flow - defined as the benefits less the costs for each year of operation in space - is given in figure 6-6. After year 12, costs are found to be dominated by building of SSPS's when mass starts to be transported from the Moon. The following 3 yr would be spent expanding the initial construction shack at L5 and building an SSPS to be used to beam energy to the Moon.

By year 22 a new shuttle system is to be operating and commercial production of SSPS's begun. Colonists would start to arrive in year 20 and number 10,000, 3 years later. Costs then would be subsequently proportional to the number of SSPS's produced each year, and benefits proportional to the total number built, increasing more rapidly than costs.

Through completion of the first colony the program would cost $196.9 billion, excluding costs directly related to SSPS's and more colonies (columns 1 and 5 of table 6-9). An additional $14.7 billion would be needed to prepare for production of the demonstration SSPS's (columns 3 and 4 of table 6-9) which would cost $21.7 billion more than the value of the electricity they produce.

By year 28 annual benefits would exceed costs. Payback in costs would be achieved.

Busbar cost of electricity produced from energy gathered from space is calculated to be 8.5 mils at year 22 falling to 4.8 mils by year 70 as shown in figure 6-6 (see also appendix D). The analysis is quite sensitive to the real discount rate (including inflation) which at 10 percent gives a benefit-to-cost ratio of 1.02. If the discount rate is lowered to 8 percent, the benefit-to-cost ratio is 1.5 (see appendix G).

Still Other Alternatives

The date at which a second-generation shuttle system becomes available is important. If development started at year 3 instead of year 15, the benefit-to-cost ratio could be increased to 1.3 and the cost of the program for the initial colony would drop to $112.7 billion, but with greater annual expenditures in the early years of the program.

There are alternatives to space colonization for generating electricity from space-building the SSPS's on Earth, and using construction shacks only without building any space colony. But space colonies win over terrestrial building because they use lunar materials which cost hundreds of times less at the use point in space than do terrestrial materials. While construction shacks cost less and can be built more quickly, in the long run they are more expensive because of their operating costs.

Some Other Energy-Related Benefits

While electricity from space and lower costs of electricity to U.S. consumers may be extremely desirable and sufficient to justify a space colonization program, there are other benefits that have not been fully evaluated in the study but may be significant. Environmentally, microwave transmission of power from space for conversion into electricity at Earth, is a very clean form of energy production (see appendix H). It avoids emission of pollutants into the Earth's atmosphere and minimizes the waste heat introduced into the terrestrial environment. The conversion of microwave energy to electricity is far more efficient than any thermodynamic process - 85 percent compared with a maximum of 50 percent.

Electrical energy from space may also be the only way in which the nation can become energy independent within the same time scale of 70 years, for not only can it supply the needed quantities of electrical energy but also inexpensive electrical energy that might be used for electrolysis of water to produce transportable fuels and thereby reduce dependence on petroleum products in transportation systems.

Another subtle energy-related benefit is the widespread nature of its application to mankind. Low-income people spend a comparatively greater percentage of their income on electricity than do affluent people. Thus lower priced electricity would benefit an enormous number of people and not just a few. This benefit from space colonization offers the potential of reaching vast numbers of people in the U.S. and providing relatively low cost energy to many more in the developing nations of the world. It offers a real alternative to limited growth scenarios for underdeveloped peoples.

Table of Contents

Curator: Al Globus If you find any errors on this page contact Al Globus.

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