Space Manufacturing Facility Research Articles

A logistics model for large space power systems

Space Power Systems (SPS) have to overcome two hurdles: (1) to find an attractive design, manufacturing and assembly concept and (2) to have available a space transportation system that can provide economical logistic support during the construction and operational phases. An initial system feasibility study, some five years ago, was based on a reference system that used terrestrial resources only and was based partially on electric propulsion systems. The conclusion was: it is feasible but not yet economically competitive with other options. This study is based on terrestrial and extraterrestrial resources and on chemical (LH 2/LOX) propulsion systems. These engines are available from the Space Shuttle production line and require small changes only. Other so-called advanced propulsion systems investigated did not prove economically superior if lunar LOX is available! We assume that a Shuttle derived Heavy Lift Launch Vehicle (HLLV) will become available around the turn of the century and that this will be used to establish a research base on the lunar surface. This lunar base has the potential to grow into a lunar factory producing LOX and construction materials for supporting among other projects also the construction of space power systems in geostationary orbit. A model was developed to simulate the logistics support of such an operation for a 50-year life cycle. After 50 years 111 SPS units with 5 GW each and an availability of 90% will produce 100 × 5 = 500 GW. The model comprises 60 equations and requires 29 assumptions of the parameter involved. 60-state variables calculated with the 60 equations mentioned above are given on an annual basis and as averages for the 50-year life cycle. Recycling of defective parts in geostationary orbit is one of the features of the model. The state-of-the-art with respect to SPS technology is introduced as a variable Mg mass/MW electric power delivered. If the space manufacturing facility, a maintenance and repair facility for operational units and a space logistics operation center are included in the GEO complex, the standard computer run indicates a value of 17 Mg/MW in the (1st) year and 7.1 Mg/MW in the 50th year. Total personnel requirements in GEO are 245 (1st) and 600 in the 50th year. The average mass flow from the Moon to GEO is 55,000 Mg p.a., from the earth come 42,000 Mg p.a. These flows require about 500 lunar bus launches and 540 HLLV average launches p.a. The use of lunar resources reduce the logistic cost to 67% compared to an all earth resources scenario!

The impact of energy on industrial growth

Energy is a fundamental factor of industrial production. The industrial process consists of work performance and information processing, in terms of which the production factors and the output can be defined and aggregated. The equation of growth relates the growth of output Q to the growth of the production factors capital K, labor L, and energy flow E. It can be solved in zero order approximation with respect to time, if one assumes that the characteristic properties of the industrial system are not changed by human creativity and that the economy is far from its thermodynamic limits to growth. Then Q must be a unique function of K, L and E. The integrability conditions result in three differential equations for the elasticities of production. They are solved subject to asymptotic boundary conditions. The integral of the equation of growth with the calculated, factor-dependent elasticities of production yields the production function q = e × exp }} a 0[2 − ( l + e)/ k] + a 0 c t ( l/ e − 1){{, with q, k, l and e being the relative values of Q, K, L, and E; a 0 and c t , are the two free parameters of the theory. For given factor inputs, the GNP and the output of the industrial sector of West Germany and the output of the sector “Industries” of the United States are calculated for the years 1960–78. Deviations of theory from reality are generally less than 5%. The slump during the energy crisis (1973–75) and the subsequent recovery are well reproduced. The influence of energy prices on factor inputs and growth is discussed. An assessment of future economic developments is given, including a calculation of the impact on U.S. industrial growth of solar power satellites from space manufacturing facilities.

Construction of Satellite Solar Power Stations from Nonterrestrial Materials

O'Neill has suggested that space manufacturing facilities processing nonterrestrial materials could be used to produce satellite solar power stations which could supply electricity to the Earth in economic competition with current and envisaged energy sources. A recent summer study determined that existing designs for satellite power stations could be largely constructible from lunar materials. Cost estimates based on lift by shuttle-derived vehicles indicates that, for a total investment of approximately $100 billion, rapid production could be established with twenty 10,000 MW power stations on-line some time in the 1990's and with cost-effective exponential growth thereafter. Total transportation costs were found to be less than that for any planned Earth-based launch system. The total investment would be several times less than that planned for capital expansion of electric generating capacity in the United States. Mass driver tugs, using space-shuttle tankage as reaction mass, could serve as low-to-high Earth orbit transportation, reducing front-end cost estimates further. Selected Apollo and Amor asteroids whose velocity intervals are lower than that from the lunar surface could be used as raw materials for space manufacturing at perhaps even lower cost. For example, a mass driver tug assembled from approximately 50 shuttle flights, could retrieve an approximatelymore » 10/sup 7/ ton asteroid for space manufacturing in high orbit within a few years. Such a mission could be automated using portions of the asteroid itself as reaction mass and could provide the materials for approximately 10 satellite power stations.« less

Space Colonies and Energy Supply to the Earth

It is pointed out that a space manufacturing facility may be economically more effective than alternative industries on the earth for the construction of products which are to be used in geosynchronous or higher orbits. The suggestion is made to construct solar power stations at a space colony and relocate them in geosynchronous orbit to supply energy to the earth. Attention is given to energy problems and approaches for solving them, taking into account environmental effects and economic factors. Economic aspects of space manufacturing are discussed in some detail.