International Concrete Abstracts Portal

The age of space exploration is already here and it appears likely that, in the next 20 years, there will be permanent bases on the moon. Therefore, it is incumbent upon engineers designing lunar structures to become knowledgeable about the peculiar effects of gravity and relativity under extraterrestrial conditions. The purpose of the paper is to present a review of Newtonian physics in light of Einstein's special and general theories of relativity. In particular, Newton's classic laws of motion and gravitation are compared with modern concepts of space-time, time dilation, length contraction, equivalency principle, and other interesting aspects of relativity.

Conventional structural engineering philosophy and experience can be inappropriate when it comes to designing structures for the moon. This paper illustrates the authors' adaptation of design philosophy for concrete, which involves changing the whole value system for this material. Far from being readily available, common, and plentiful, concrete will be an exotic and precious material on the moon. The use of concrete is proposed for such efficient structures as thin shell rather than the more common planar structures more suitable for earth. The structure containing one atmospheric pressure inside must be pressurized to resist such pressure, and a new value system must be derived.

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.