Petrographic survey of lunar regolith breccias

Regolith breccias from the Moon and from parent bodies of some meteorites may provide samples of ancient regoliths which have been frozen in time. If these rocks were essentially closed at some earlier time and that time can be determined, then these rocks provide a record of conditions in the solar system at that point in time. A survey of regolith breccias in the Apollo collection was conducted concentrating initially on Apollo 15 and 16. All available thin sections for 32 regolith breccias from Apollo 15 and 19 breccias from Apollo 16 were surveyed. These are most of the returned regolith breccias larger than 1 cm from these two mission. For comparison several fragmental matrix breccias which do not strictly qualify as regolith breccias were investigated. The criteria for classification as a regolith breccia is the presence of identifiable soil components such as glass spheres or agglutinates. The breccias are classified according to their intergranular porosity. In addition the fracture porosity is noted, and the relative abundance of agglutinates and spheres. Several petrographic trends are also noted. Identifiable regolith material decreases with decreasing intergranular porosity while fracture porosity increases. This relative lack of maturity of regolith breccias mayreflect their generally earlier formation age an the maturity of the regolith at that earlier time

Space resources. Volume 4: Social concerns

Space resources must be used to support life on the Moon and exploration of Mars. This volume, Social Concerns, covers some of the most important issues which must be addressed in any major program for the human exploration of space. The volume begins with a consideration of the economics and management of large scale space activities. Then the legal aspects of these activities are discussed, particularly the interpretation of treaty law with respect to the Moon and asteroids. The social and cultural issues of moving people into space are considered in detail, and the eventual emergence of a space culture different from the existing culture is envisioned. The environmental issues raised by the development of space settlements are faced. Some innovative approaches are proposed to space communities and habitats and self-sufficiency is considered along with human safety at a lunar base or outpost

Space resources. Volume 1: Scenarios

A number of possible future paths for space exploration and development are presented. The topics covered include the following: (1) the baseline program; (2) alternative scenarios utilizing nonterrestrial resources; (3) impacts of sociopolitical conditions; (4) common technologies; and issues for further study

Space resources. Overview

Space resources must be used to support life on the Moon and in the exploration of Mars. Just as the pioneers applied the tools they brought with them to resources they found along the way rather than trying to haul all their needs over a long supply line, so too must space travelers apply their high technology tools to local resources. This overview describes the findings of a study on the use of space resources in the development of future space activities and defines the necessary research and development that must precede the practical utilization of these resources. Space resources considered included lunar soil, oxygen derived from lunar soil, material retrieved from near-Earth asteroids, abundant sunlight, low gravity, and high vacuum. The study participants analyzed the direct use of these resources, the potential demand for products from them, the techniques for retrieving and processing space resources, the necessary infrastructure, and the economic tradeoffs

Fluid flow analysis by a modified, white light, Lau interferometer

This paper presents a sharp focussing schlieren system based upon a modified Lau interferometer. A method of reducing the depth of focus of the system is demonstrated and the development of the system to study large fields of view by theincorporation of flexible membrane mirrors is discussed

On Birthing Dancing Stars: The Need for Bounded Chaos in Information Interaction

While computers causing chaos is acommon social trope, nearly the entirety of the history of computing is dedicated to generating order. Typical interactive information retrieval tasks ask computers to support the traversal and exploration of large, complex information spaces. The implicit assumption is that they are to support users in simplifying the complexity (i.e. in creating order from chaos). But for some types of task, particularly those that involve the creative application or synthesis of knowledge or the creation of new knowledge, this assumption may be incorrect. It is increasingly evident that perfect order—and the systems we create with it—support highly-structured information tasks well, but provide poor support for less-structured tasks.We need digital information environments that help create a little more chaos from order to spark creative thinking and knowledge creation. This paper argues for the need for information systems that offerwhat we term ‘bounded chaos’, and offers research directions that may support the creation of such interface

The origin of amorphous rims on lunar plagioclase grains: Solar wind damage or vapor condensates

A distinctive feature of micron sized plagioclase grains from mature lunar soils is a thin (20 to 100 nm) amorphous rim surrounding the grains. These rims were originally described from high voltage electron microscope observations of lunar plagioclase grains by Dran et al., who observed rims up to 100 nm thick on plagioclase grains from Apollo 11 and 12 soils. These rims are believed to be the product of solar wind damage. The amorphous rims were studied on micron sized plagioclase grains from a mature Apollo 16 soil using a JEOL 200FX transmission electron microscope equipped with an energy dispersive x ray spectrometer. It was found that the amorphous rims are compositionally distinct from the interior plagioclase and it is proposed that a major component of vapor condensates is present in the rims

Take Me Out: Space and Place in Library Interactions

Information interactions are strongly affected by the place where they occur. Specific locations are ofen associated with searches on particular topics, and individual users perform different tasks in habituated places. A classic example of habituated space is the commuter who regularly reads the news on the train. This paper investigates these associations through four user studies that examine different uses of place in information interaction. Through this, we reveal the ways in which the location of information interactions makes them effective or ineffective. This extends our interpretation of the role of place in information interaction beyond established foci such as location-based search

Random Matrix Models, Double-Time Painlev\'e Equations, and Wireless Relaying

This paper gives an in-depth study of a multiple-antenna wireless communication scenario in which a weak signal received at an intermediate relay station is amplified and then forwarded to the final destination. The key quantity determining system performance is the statistical properties of the signal-to-noise ratio (SNR) \gamma\ at the destination. Under certain assumptions on the encoding structure, recent work has characterized the SNR distribution through its moment generating function, in terms of a certain Hankel determinant generated via a deformed Laguerre weight. Here, we employ two different methods to describe the Hankel determinant. First, we make use of ladder operators satisfied by orthogonal polynomials to give an exact characterization in terms of a "double-time" Painlev\'e differential equation, which reduces to Painlev\'e V under certain limits. Second, we employ Dyson's Coulomb Fluid method to derive a closed form approximation for the Hankel determinant. The two characterizations are used to derive closed-form expressions for the cumulants of \gamma, and to compute performance quantities of engineering interest.Comment: 72 pages, 6 figures; Minor typos corrected; Two additional lemmas added in Appendix

Helical rotary screw expander power system

An energy converter for the development of wet steam geothermal fields is described. A project to evaluate and characterize a helical rotary screw expander for geothermal applications is discussed. The helical screw expander is a positive displacement machine which can accept untreated corrosive mineralized water of any quality from a geothermal well. The subjects of corrosion, mineral deposition, the expansion process, and experience with prototype devices are reported