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.
TABLE 6-4 — HABITATS
| Habitat | Mass (t)* | R&D Cost ($B)** | Purchase ($B)*** | | :--- | :--- | :--- | :--- | | LEO Station | 500 | 2.5 | 0.25 | | Lunar Base | 2000 | 1.0† | 1.0 | | Construction Shack | 22,000 | 1.0† | 11.0 | | Colony Shell | 156,000 | 1.0† | 78.0††† | | Colony Shield | 9.9 X 10⁶ | — | — |
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- Mass per person used is between the 10 t/person of the NASA 100 person space base and the 3.5 t/person of G. W. Drigger's design (paper presented at Princeton Conference on Space Manufacturing Facilities, May, 1975). The lunar base is expected to withstand the weight of lunar soil covering for shielding and to be more permanent.
- ** Research and development through first unit at $5000/kg.
- *** Designed for construction crew of 300; permanently occupied by operational crew of 150.
- † Cost for first unit makes use of R&D done for LEO station; $500/kg purchased on Earth.
- †† Normal Earth materials costed at $5/kg.
- ††† NASA estimates.
- All costs expressed in 1975 dollars.
TABLE 6-6 — LABOR SCHEDULE
| Year | LEO | Moon | L5 | Total | | :--- | :--- | :--- | :--- | :--- | | 5 | 100 | 0 | 0 | 100 | | 6 | 100 | 0 | 0 | 100 | | 7 | 100 | 0 | 0 | 100 | | 8 | 100 | 0 | 0 | 100 | | 9 | 100 | 0 | 0 | 100 | | 10 | 100 | 300 | 300 | 700 | | 11 | 100 | 300 | 300 | 700 | | 12 | 100 | 300 | 300 | 700 | | 13 | 100 | 300 | 300 | 700 | | 14 | 100 | 300 | 300 | 700 | | 15 | 0 | 150 | 4400 | 4550 | | 16 | 0 | 150 | 4400 | 4550 | | 17 | 0 | 150 | 4400 | 4550 | | 18 | 0 | 150 | 4400 | 4550 | | 19 | 0 | 150 | 4400 | 4550 | | 20 | 0 | 150 | 4400 | 4550 | | 21 | 0 | 150 | 4400 | 4550 | | 22 | 0 | 150 | 4400 | 4550 |
- *K denotes 1000.
TABLE 6-5 — SCHEDULE OF TASKS
| Year | Task* | Cost ($B)** | Payloads (t)† | | :--- | :--- | :--- | :--- | | 1-5 | Research on Earth (E) | 1.6 | — | | 5-9 | LEO Station (O) | 2.5 | (500) | | 5-9 | Transportation R&D (E) | 18.5 | — | | 5-9 | Energy R&D (E) | 2.0 | — | | 5-9 | Extraction/Fabrication R&D (E) | 2.0 | — | | 5-9 | Mass Launcher/Catcher R&D (E) | 2.0 | — | | 10 | Lunar Base (M) | 1.0 | (2000) | | 10 | Lunar Power (M) | 0.5 | (9900) | | 10 | Construction Shack (L5) | 11.0 | (22,000) | | 10 | L5 Power (L5) | 0.5 | (2800) | | 11 | Extraction Plant (L5) | 0.5 | (7500) | | 11 | Fabrication Plant (L5) | 0.5 | (3300) | | 12 | Mass Launcher (M) | 0.5 | (300) | | 12 | Mass Catcher (L2) | 0.5 | (220) | | 12 | >> Mass Flow (M to L5) | — | 1.2 X 10⁶/yr | | 13 | >> Extraction (L5) | — | 1.5 X 10⁵/yr | | 14 | >> Fabrication (L5) | — | 9 X 10⁴/yr | | 15-20 | Colony Shell (L5) | 78.0††† | — | | 15-22 | >> Colony Shield (L5) | — | — | | 20-23 | >> Immigration (L5) | — | — |
- *E indicates effort on Earth, O in Earth orbit, M on the Moon, L and L5, L2 at L2.
- ** Research and development costs are $5 X 10⁶/t.
- *** >> denotes the time at which the system becomes operational.
- †( ) indicates masses which are payloads.
- †† NASA estimates.
- ††† Construction cost is $0.5 X 10⁶/t after experience gained at LEO.
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 tables 6-5 through 6-7.
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. These results are summarized in figure 6-2. In addition, the total costs are given as: research, $1.6 billion; development, $28.5 billion; production, $14.6 billion; and transportation, $114.3 billion. Including a 20 percent overhead charge of $31.8 billion, the total cost of the system is thus $190.8 billion, where all costs are expressed in 1975 dollars. Figure 6-2 also shows that the availability of oxygen in space dramatically reduces the transportation costs which are still over half of the total system costs. A detailed breakdown of these cost data is given in table 6-8.
Chapter 6 — Building The Colony And Making It Prosper
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PRODUCTION OF ENERGY IN SPACE AS A POTENTIAL ECONOMIC JUSTIFICATION FOR SPACE COLONIZATION
Beyond the Initial Cost Estimate
The study looked into ways in which a space colonization program might be economically justified. One way, and perhaps the most promising, is production of SSPS's to satisfy terrestrial demands for energy. In the following sections the cost effectiveness of this production is discussed and important factors affecting economic viability are identified.
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.
TABLE 6-9 — ADJUSTMENTS IN BILLIONS OF 1975 DOLLARS TO THE COSTS GIVEN IN FIGURE 6-2*
| Year | Baseline Costs (1) | SSPS R&D (2) | L5/Moon Expansion (3) | Lunar Power (4) | 2nd Gen. Shuttle (5) | | :--- | :--- | :--- | :--- | :--- | :--- | | 1-5 | 1.6 | — | — | — | — | | 6 | 3.1 | 0.5 | — | — | — | | 7 | 3.1 | 0.5 | — | — | — | | 8 | 3.1 | 0.5 | — | — | — | | 9 | 3.1 | 0.5 | — | — | — | | 10 | 13.9 | 0.5 | — | 0.5 | — | | 11 | 13.9 | 0.5 | 0.5 | 0.5 | — | | 12 | 13.9 | 0.5 | 0.5 | 0.5 | — | | 13 | 13.9 | 0.5 | 0.5 | 0.5 | — | | 14 | 13.9 | 0.5 | 0.5 | 0.5 | — | | 15 | 13.4 | — | 0.5 | — | 1.3 | | 16 | 13.4 | — | 0.5 | — | 1.3 | | 17 | 13.4 | — | 0.5 | — | 1.3 | | 18 | 13.4 | — | 0.5 | — | 1.3 | | 19 | 13.4 | — | 0.5 | — | 1.3 | | 20 | 13.4 | — | 0.5 | — | 1.3 | | 21 | 13.4 | — | 0.5 | — | 1.3 | | 22 | 13.4 | — | 0.5 | — | — |
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- 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.
- ** Indicates columnar numbers referred to in text.
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 costs of 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.
Figure 6-3 — The production schedule for terrestrial satellite solar power stations.
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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.
At year 11 a rectenna must be built on the Moon to be ready to receive power from the lunar SSPS in year 15. Its receiving capacity is increased as needed in subsequent years. Parts of the rectenna can be fabricated on the Moon from lunar materials, for which chemical processing and fabricating equipment would be placed on the Moon at year 10. This equipment would also be used to expand the lunar base and to produce additional mass drivers. Costs of these lunar expansion activities are given in column 4 of table 6-9, including the cost of producing the lunar SSPS at L5. (See appendix B for technical details of the power system.)
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.)
Figure 6-4 — The production schedule for colonies.
<!-- image -->Figure 6-5 — Total costs and electricity benefits.
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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 for nuclear 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 10-GW 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).