International Concrete Abstracts Portal

Lunar Concrete is the exciting new symposium volume which explores the production and use of concrete on the moon. Contained within 20 technical papers from well-known authorities on lunar concrete are details on lunar base construction, use of lunar resources, lunar concrete formulation, forming and placing lunar concrete, reinforcing lunar concrete, and environmental effects of lunar concrete, optimizing lunar concrete and much more. It may at first seem outrageous that concrete could be considered as primary material of construction for use on the Moon. However, a small group of scientists and engineers, many of them represented in this collection of papers, have persevered in examining this outrageous premise. Most, perhaps all, of the materials needed to make concrete are naturally present on the lunar surface. Although they have to be extracted and transformed, the energy required to do that, and probably the cost, is much less than that which would be required to bring the same quantity of material from the Earth to use on the Moon. The technology for utilizing these natural materials of the Moon would appear to be straightforward modifications of techniques that have been developed for terrestrial applications. Note: The individual papers are also available as .pdf downloads.. Please click on the following link to view the papers available, or call 248.848.3800 to order. SP125

The moon offers a stable platform with excellent visual conditions for astronomical observations. Some troublesome aspects of the lunar environment must be overcome to realize the full potential of the moon as an observatory site. Mitigation of negative effects of vacuum, thermal radiation, dust, and micrometeorite impact is feasible with careful engineering and operational planning. Shields against impact, dust, and solar radiation must be developed. Means of restoring degraded surfaces are probably essential for optical and thermal control surfaces deployed on long-lifetime lunar facilities. Precursor missions should be planned to validate and enhance the understanding of the lunar environment (e.g., dust behavior with and without human presence) and to determine environmental effects on surfaces and components. Precursor missions should generate data useful in establishing keepout zones around observatory facilities where rocket launches and landings, mining, and vehicular traffic could be detrimental to observatory operation. If lunar concrete becomes available, it could be a material of choice for observatory foundation construction. For concrete to be a viable choice, its production and use must be compatible with the observatories' needs for clean, precision optics, and for an environment free of dust, shock, vibration, and outgassing. It must also be economically competitive with alternative construction techniques.

It has been proposed that a large pressurized shirt sleeve environment assembly facility would be useful during all phases of lunar outpost development. This article discusses the use of such a facility during later phases of outpost development when use of native materials is maximized. The principle benefits from the use of a large pressurized facility are that workers needn't wear cumbersome, restrictive space suits and concrete needn't be cured in the vacuum environment of the moon. A specific assembly facility concept is presented and its conversion to a lunar precast concrete plant is discussed.

Early in the next century, humans will return to the surface of the moon for stays of increasingly longer duration. Many civil engineering challenges must be addressed so that these twenty-first century pioneers will have the shelter and life-support systems needed to survive and thrive in a largely benign but, in some ways, hostile environment. Depending on the stage of the lunar presence, different structures and processes will be feasible. Reliance on lunar resources, including manufactured forms such as lunar concrete, will become more important as the base size and maturity grows. It is the task of the universities in these endeavors to provide the basic knowledge to help meet these challenges and to produce enthusiastic and well-prepared graduates who can best continue to develop the solutions needed to support the expansion of humans into space. Educational programs in space civil engineering now undergoing development at Colorado State University under a NASA space grant college program are described. An undergraduate option that supplements the existing civil engineering program through a cluster of classes that can be taken within the existing elective structure is being developed. Concepts for an MS graduate program are also outlined.

In the lunar environment, the use of solar thermal energy has obvious advantages over any combustion or electrical furnace for driving high-temperature processes. However, extremely high temperatures, in the range of 1700 to 2000 C, will be necessary to produce cement from lunar minerals and will, in turn, require very high levels of solar flux concentration. Such levels can only be achieved in practice with some form of ideal or near-ideal nonimaging concentrator that can approach the maximum concentration permitted by physical conservation laws. In particular, very substantial gains in efficiency can be generated through the incorporation of a properly designed ideal or near-ideal nonimaging secondary concentrator in a two-stage configuration with a long focal ratio primary concentrator. A preliminary design configuration for such a high-flux nonimaging solar concentrating furnace for lunar applications is presented. It employs a tracking heliostat and a fixed, off-axis, two-stage concentrator with a long focal length utilizing a nonimaging trumpet or CPC-type secondary deployed in the focal zone of the primary. An analysis of the benefits associated with this configuration employed as a solar furnace in the lunar environment shows that the thermal conversion efficiency can be about 3 to 5 times that of the corresponding conventional design at 2000 C. Furthermore, this configuration allows the primary collecting aperture to remain unshaded by the furnace or any associated support structure.