Image
APPENDIX D: METHODS FOR ESTIMATING COST AND TIME FOR SSPS AND MORE COLONIES
To guard against the possibility of cost underestimates in the earlier studies of the F-1 and to satisfy the need to develop a hydrogen-oxygen system for environmental reasons, this study assumes that the cost of the second generation system is $9 billion (rather than $5 billion) spread over a 7-yr period. Regardless of whether the F-1 or some other system is developed, performance characteristics are assumed to be a transportation cost to low Earth orbit of $55/kg of freight and $80,000 per person. Table 6-11 gives the transportation costs for people and freight to L5 and the Moon over the whole program.
Column 3 of Table 6-12 gives the number of new terrestrial SSPS's produced per year. The program is set up so that from the first year of production the level of output is always equal to the demand for terrestrial SSPSs, which is calculated in appendix E. That appendix shows that the level of demand depends in part on the year in which production begins. To determine demand, year 1 of the program is assumed as 1976.
To avoid undue complexity, composite variables are used in the analysis for two major variables — SSPS's and all colonies other than the first. Costs of a composite are obtained by aggregating costs of its components, including a propellant as a by-product of refining at L5, the mass which must be brought to LEO becomes approximately twice the payload to L5 and 3.3 times the payload to L2 or to the lunar surface (Austin, G., Marshall Space Flight Center, Alabama, personal communication, Aug. 15, 1975). These factors include return of transportation hardware to its point of origin following each mission.
TABLE 6-11 — TRANSPORTATION COSTS
| Destination | Years 5-11¹ | Years 12-21² | Years 22-70³ | | :--- | :--- | :--- | :--- | | Freight ($/kg) | | | | | LEO | 200 | 200 | 55 | | L5 | 800 | 400 | 110 | | Moon | 1600 | 660 | 180 | | People ($/person) | | | | | LEO | 440,000 | 440,000 | 80,000 | | L5 | 1,760,000 | 880,000 | 160,000 | | Moon | 3,520,000 | 1,452,000 | 264,000 |
- 1 Before year 5 the program involves no transportation. The Space Shuttle and HLLV became available for use in year 5.
- 2 O₂ becomes available in space for rocket propellant.
- 3 The second-generation shuttle becomes available.
TABLE 6-7 — PAYLOAD SCHEDULE (t)
| Year | LEO | Moon | L5 | | :--- | :--- | :--- | :--- | | 5 | 100 | 0 | 0 | | 6 | 100 | 0 | 0 | | 7 | 100 | 0 | 0 | | 8 | 100 | 0 | 0 | | 9 | 100 | 0 | 0 | | 10 | 0 | 11,900 | 24,800 | | 11 | 0 | 0 | 10,800 | | 12 | 0 | 300 | 220 | | 13 | 0 | 0 | 0 | | 14 | 0 | 0 | 0 | | 15 | 0 | 0 | 0 | | 16 | 0 | 0 | 0 | | 17 | 0 | 0 | 0 | | 18 | 0 | 0 | 0 | | 19 | 0 | 0 | 0 | | 20 | 0 | 0 | 0 | | 21 | 0 | 0 | 0 | | 22 | 0 | 0 | 0 |
TABLE 6-8 — DETAILED COST DATA ($B)
| Year | R&D | Purchase | Transportation | Resupply | Total | | :--- | :--- | :--- | :--- | :--- | :--- | | 1-5 | 1.6 | — | — | — | 1.6 | | 6 | 5.4 | 0.1 | 0.1 | 0.1 | 5.7 | | 7 | 5.4 | 0.1 | 0.1 | 0.1 | 5.7 | | 8 | 5.4 | 0.1 | 0.1 | 0.1 | 5.7 | | 9 | 5.4 | 0.1 | 0.1 | 0.1 | 5.7 | | 10 | 1.0 | 6.5 | 18.2 | 0.6 | 26.3 | | 11 | 1.0 | 0.5 | 4.3 | 0.6 | 6.4 | | 12 | 1.0 | 0.5 | 0.2 | 0.6 | 2.3 | | 13 | 1.0 | 0.5 | — | 0.6 | 2.1 | | 14 | 1.0 | 0.5 | — | 0.6 | 2.1 | | 15 | — | 13.0 | — | 4.0 | 17.0 | | 16 | — | 13.0 | — | 4.0 | 17.0 | | 17 | — | 13.0 | — | 4.0 | 17.0 | | 18 | — | 13.0 | — | 4.0 | 17.0 | | 19 | — | 13.0 | — | 4.0 | 17.0 | | 20 | — | 13.0 | — | 4.0 | 17.0 | | 21 | — | 13.0 | — | 4.0 | 17.0 | | 22 | — | — | — | 4.0 | 4.0 |
All costs expressed in 1975 dollars.
charge for use of capital and an adjustment for the cost of maintenance. Methodology and costs of the major components are set forth in appendix F.
Costs for each of the composites are expressed by 5 variables whose initial values are: for an SSPS, $9.73 billion plus the costs associated with obtaining 3,398 man-years of labor at L5; 700 man-years of labor on the Moon; and 557 man-years of labor in other locations in space. In addition, the costs of 22.98 percent of a chemical processing and fabricating plant at L5 is charged to the SSPS. These costs decrease over time due to learning curves and the introduction of the second-generation shuttle system. Second and later colonies are only produced after the second-generation shuttle system has been introduced. Their costs are also affected by learning curves. To begin with, colonies cost $9.24 billion, 20,946 man-years at L5, 1759 man-years on the Moon, 626 man-years elsewhere in space, and a chemical processing and fabricating charge of 0.5741 L5 plants.
Man-year requirements for both SSPS's and colonies are assumed to decrease as additional units are produced with an 80 percent learning curve, found to be empirically valid in the aircraft industry (refs. 5, 6). The level of output of new terrestrial SSPS's coupled with the labor costs of an SSPS and the assumption that an SSPS is produced within 1 yr, determine the number of workers needed at L5 for SSPS construction, as given in column 4 of table 6-12. Column 5 of table 6-12 gives the number of new and old colonies. Columns 6 and 7 give the number of SSPS workers in colonies and construction shacks, respectively.
The timing of the nonlabor costs for building any particular colony other than the first is determined by assuming that expenditures are proportional to the labor input. Column 9 gives the number of new chemical processing and fabricating plants that are needed for a given year at L5 to build the scheduled number of SSPS's and second and later colonies. The initial chemical processing and fabricating plant has a mass of 10,800 t. It all comes from Earth. The cost of material purchased on Earth for all plants is assumed to be $600/kg. Taking into consideration the previously-mentioned learning curve and the cost of transportation for the year in question, the costs of all plants can be determined. Next, for each year, the average cost is computed of plants that have been placed at L5 during that year or any preceding year for the purpose of building terrestrial SSPS's or second and later colonies. Similarly for colonies, the total nonlabor costs in dollars of terrestrial SSPS's and of second and later colonies are given in columns 10 and 11.
Column 13 gives the costs of labor. It is assumed that every colonist obtains 100 kg from the Earth annually and that the purchase price on Earth is $5/kg. Luxury goods and various consumable goods produced within the colony make up the colonists' wages. The costs for a worker who is not a colonist consist of wages, crew rotation costs, and supplies from Earth. Wages cost $120,000 per worker for each year spent in space. Each noncolonist also requires 1.67 t of supplies from Earth per year, costing $5/kg purchase price on Earth plus transportation. Besides workers who live in construction shacks at L5 all workers not at L5 are assumed to be noncolonists. Column 14 gives the total costs.
The total of terrestrial SSPS's being used, column 15, is the sum of all terrestrial SSPS's built during the previous year or before, minus those worn out after an assumed lifetime of 30 yr. The derivation of the benefits listed in column 16 is discussed in appendix E.
The last column of table 6-12 gives the costs of the power produced after SSPS's come into commercial production. The cost of second and later colonies is thereby incorporated since they are needed to house the required labor. It is assumed that the resulting cost must be paid over the 30-year lifetime of the SSPS. A level charge for the 30-year period, which also covers interest at a real rate of 10 percent is then computed. The same procedure is followed so as to compute a level charge for all terrestrial SSPS's. To obtain the cost of electricity for a particular year, the level charges of all terrestrial SSPS's which produce electricity in that year are averaged.
APPENDIX E
ELECTRICITY BENEFITS
This analysis assumes that the funding organization is American as compared to international, and that the only benefits tallied are those which occur to Americans who remain on Earth.
Prices
The price of electricity is approximately equal to its cost plus a normal rate of profit. Busbar costs are the costs of power at the generation station; for SSPS's, the receiving antenna. They do not include the costs of distributing the power through the electrical grid to consumers. In 1974 the cost of electricity produced by nuclear (light water reactor) plants was 15 mils/kW-hr, by coal 17 mils, and by oil considerably more (refs. 3 and 7). The cost of electricity today is not as important as what it will be in the future. An optimistic projection is a constant price until 2045 of 14.1 mils (ref. 7).
There are several terrestrial-based technologies such as the fast breeder reactor, fusion, and central station solar which might be developed during the period under consideration. The least expensive of these will probably be able to produce electricity at 11.6 mils, not including a charge for development costs. When the latter cost is taken into consideration as well, it is reasonable to take 14.1 mils as the price which space colonization power must meet to be competitive (Manne, A., personal communication, June 24, 1975).
The market for electricity can be divided into two types, baseload and peakload. The baseload market is where the sources which generate electrical power are run until maintenance requires a shut-down. Peakload plants are run for much less time to satisfy fluctuating demands for electricity with the hour of the day and the time of year.
All of the costs given in appendix D assume that the electricity produced is used in the baseload market. Since space colony power is cheaper than its competitors, all new baseload plants are likely to be SSPS's.
Manne and Yu (ref. 7) project a fixed cost of a constant 7.2 mils for coal and 9.6 mils for nuclear, while the variable costs are 12.0 mils for coal and 4.5 mils for nuclear. The costs of peakload power are the fixed costs plus a fraction of the variable costs which depends on the amount of plant utilization. In the absence of space colonization, coal will dominate the peakload market, as well as be important in the baseload market. The fixed cost of 7.2 mils for coal suggests that space colonization power will not compete in much of the peakload market. When new plants are needed for the peakload market, rather than build new coal plants, it would be more economical to convert some of the coal plants from the baseload to the peakload market and replace the loss in the baseload market with SSPS's.
For the foreign market it was assumed that no power would be sold to other nations for the first 2 years after the introduction of the first power plant. Afterward, one-third of the power produced would be sold abroad. This level of exports is consistent with past experience of building and selling nuclear, central-station electric power reactors (ref. 1).
The growth rate of electricity demand is assumed to be 5 percent per year. The Energy Research and Development Administration's scenarios, for 1975-2000 (ref. 2), involve a growth rate of 5.7 percent for intensive electrification. Since space colonization could lead to a large supply of low-cost electricity, it would imply that a 5 percent growth rate appears reasonable. The 5 percent growth rate was chosen to be consistent with a price of 14.1 mils. The consistency of a 14.1 mil price and a 5 percent growth rate is supported by Manne and Yu (ref. 7) and Hudson and Jorgenson (ref. 8).