Geoscience and a Lunar Base: A Comprehensive Plan for Lunar Exploration

This document represents the proceedings of the Workshop on Geoscience from a Lunar Base. It describes a comprehensive plan for the geologic exploration of the Moon. The document begins by explaining the scientific importance of studying the Moon and outlines the many unsolved problems in lunar science. Subsequent chapters detail different, complementary approaches to geologic studies: global surveys, including orbiting spacecraft such as Lunar Observer and installation of a global geophysical network; reconnaissance sample return mission, by either automated rovers or landers, or by piloted forays; detailed field studies, which involve astronauts and teleoperated robotic field geologists. The document then develops a flexible scenario for exploration and sketches the technological developments needed to carry out the exploration scenario

Master of Science

thesisTraffic simulations, which attempt to describe how individual vehicles move on road segments in a network, rely on mathematical traffic flow models developed from empirical vehicle trajectory data (position, speed, acceleration, etc.). Many of these microscopic traffic flow models are described as car-following models, which assume that a driver will respond to the actions of the driver/s or vehicle/s located in front of them (stimulus-response behavior). Model calibration can be performed using regression and/or optimization techniques, but the process is often complicated by uncertainty and variation in human behavior, which can be described as driver heterogeneity. Driver heterogeneity is conceptually based on the idea that different drivers may have different reactions to the same stimuli (interdriver heterogeneity), and an individual driver may react differently to the same type of stimulus (intradriver heterogeneity). To capture interdriver heterogeneity, car-following model parameters must be estimated for each driver/vehicle in the dataset, which are then used to describe a probability distribution associated with those model parameters. Capturing intradriver heterogeneity requires going one step further, calculating those same model parameters over much smaller time periods (i.e., seconds, or fractions of sections) within one vehicle's trajectory. This significantly reduces the amount of data available for calibration, limiting the ability to use traditional calibration procedures

Methods for the Aerostructural Design and Optimization of Wings with Arbitrary Planform and Payload Distribution

The design of an aircraft wing often involves the use of mathematical methods for simultaneous aerodynamic and structural design. The goal of many of these methods is to minimize the drag on the wing. A variety of computer models exist for this purpose, but some require the use of expensive time and computational resources to give meaningful results. As an alternative, some mathematical methods have been developed that give reason ably accurate results without the need for a computer. However, most of these methods can only be used for wings with specific shapes and payload distributions. In this thesis, a hybrid mathematical/computational approach to wing design is developed that can be used for wings of any shape with any payload distribution. Specific mathematical expressions are found to predict the weight and drag for tapered wings and elliptic-shaped wings. The new approach and mathematical expressions are used to find the best distribution of lift on a variety of aircraft wing configurations to minimize drag during flight

Multidisciplinary Reference Solutions for Performance-Optimized Aircraft Wings with Tailored Aerodynamic Load Distributions

Morphing wings, or wings that can change shape during flight, have the potential to substantially reduce the amount of fuel consumed by an aircraft over the course of its flight. However, the extent to which these wings can reduce fuel consumption depends on the design of the wing, including its aerodynamic efficiency and its structural layout, and how the aircraft flies, including its flight altitude and speed. Correctly predicting how these design and operational characteristics interact is critical to predicting how wing morphing may affect aircraft fuel consumption. Many computer prediction tools exist that include the effects of these interactions, but extracting the information needed to understand how the interactions work from most of these tools is very difficult. In this dissertation, some simplified models are presented that more directly reveal key information about the interplay between aerodynamics, structures, control, and the flight trajectory in the design of morphing wings. This information is used to characterize the impacts of wing morphing on aircraft efficiency

Lithologies contributing to the clast population in Apollo 17 LKFM basaltic impact melts

LKFM basaltic impact melts are abundant among Apollo lunar samples, especially those from Apollo 15, 16, and 17. They are generally basaltic in composition, but are found exclusively as impact melts. They seem to be related to basins and so could represent the composition of the lower lunar crust. They contain lithic clasts that cannot be mixed in any proportion to produce the composition of the melt matrix; components rich in transition elements (Ti, Cr, Sc) and REE are not considered. To search for the mysterious cryptic component, we previously investigated the mineral clast population in two Apollo 14 LKFM basaltic impact melts, 15445 and 15455. The cryptic component was not present in the mineral clast assemblage of these breccias either, but some olivine and pyroxene grains appeared to be from lithologies not represented among identified igneous rocks from the lunar highlands. In addition, none of the mineral clasts could be unambiguously assigned to a ferroan anorthosite source. We have now extended this study to Apollo 17, starting with two LKFM impact melt breccias (76295 and 76315) from the Apollo 17 station 6 boulder. The results from the study are presented

LONG-RUN STRIGA CONTROL BY SUBSISTENCE FARMERS IN MALI

A dynamic programming model is developed to identify barriers to the adoption of long-run control programs for the parasitic weed Striga. The model is applied to Sirakorola in northwestern Mali. The ability of national and village-level institutions to overcome the barriers to adoption is explored.Community/Rural/Urban Development, Research and Development/Tech Change/Emerging Technologies,

Low-Fidelity Method for Rapid Aerostructural Optimisation and Design-Space Exploration of Planar Wings

During early phases of wing design, analytic and low-fidelity methods are often used to identify promising design concepts. In many cases, solutions obtained using these methods provide intuition about the design space that is not easily obtained using higher-fidelity methods. This is especially true for aerostructural design. However, many analytic and low-fidelity aerostructural solutions are limited in application to wings with specific planforms and weight distributions. Here, a numerical method for minimising induced drag with structural constraints is presented that uses approximations that apply to unswept planar wings with arbitrary planforms and weight distributions. The method is applied to the National Aeronautics and Space Administration (NASA) Ikhana airframe to show how it can be used for rapid aerostructural optimisation and design-space exploration. The design space around the optimum solution is visualised, and the sensitivity of the optimum solution to changes in weight distribution, structural properties, wing loading and taper ratio is shown. The optimum lift distribution and wing-structure weight for the Ikhana airframe are shown to be in good agreement with analytic solutions. Whereas most modern high-fidelity solvers obtain solutions in a matter of hours, all of the solutions shown here can be obtained in a matter of seconds

Comparison of Theoretical and Multi-Fidelity Optimum Aerostructural Solutions for Wing Design

As contemporary aerostructural research for aircraft design trends toward high-fidelity computational methods, aerostructural solutions based on theory are often neglected or forgotten. In fact, in many modern aerostructural wing optimization studies, the elliptic lift distribution is used as a benchmark in place of theoretical aerostructural solutions with more appropriate constraints. In this paper, we review several theoretical aerostructural solutions that could be used as benchmark cases for wing design studies, and we compare them to high-fidelity solutions with similar constraints. Solutions are presented for studies with 1) constraints related to the wing integrated bending moment, 2) constraints related to the wing root bending moment, and 3) structural constraints combined with operational constraints related to either wing stall or wing loading. It is shown that for each set of design constraints, the theoretical optimum lift distribution is consistently in excellent agreement with high-fidelity results. It follows that theoretical optimum lift distributions can often serve as a good benchmark for higher fidelity aerostructural wing optimization methods. Moreover, a review of solutions for the optimum wingspan and corresponding drag reveals important insights into the effects of viscosity, aeroelasticity, and compressibility on the aerodynamic and structural coupling involved in wing design and optimization

The Complex Stratigraphy of the Highland Crust in the Serenitatis Region of the Moon Inferred from Mineral Fragment Chemistry

Large impact basins are natural drill holes into the Moon, and their ejecta carries unique information about the rock types and stratigraphy of the lunar crust. We have conducted an electron microprobe study of mineral fragments in the poikilitic melt breccias collected from the Taurus Mountains at the Apollo 17 landing site. These breccias are virtually unanimously agreed to be impact melt produced in the Serenitatis impact event. They contain lithic fragments and much more abundant mineral fragments of crustal origin. We have made precise microprobe analyses of minor element abundances in fragments of olivine, pyroxene, and plagioclase to provide new information on the possible source rocks and the crustal stratigraphy in the Serenitatis region. These data were also intended to elucidate the nature of the cryptic geochemical component in breccias such as these with low-K Fra Mauro basalt compositions. We chose the finest-grained (i.e., most rapidly quenched) breccias for study, to avoid reacted and partly assimilated fragments as much as possible. Most of the mineral fragments appear to have been derived from rocks that would fall into the pristine igneous Mg-suite as represented by lithic fragments in the Apollo collection, or reasonable extensions of it. Gabbroic rocks were more abundant in the target stratigraphy than is apparent from the Apollo sample collection. Some pyroxene and plagiociase, but probably not much olivine, could be derived from feldspathic granulites, which are metamorphosed polymict breccias. Some mineral fragments are from previously unknown rocks. These include highly magnesian olivines (up to Fo(sub 94)), possibly volcanic in origin, that exacerbate the difficulty in explaining highly magnesian rocks in the lunar crust. It appears that some part of the lunar interior has an mg*(= 100 x Mg/(Mg/Fe) atomic) greater than the conventional bulk Moon value of 80-84. Other volcanic rocks, including mare basalts, and rapidly- cooled impact melt rocks do not contribute significantly to the fragment population. Nor do ferroan anorthosites contribute more than a tiny part of even the plagiociase fragment population. A few mineral fragments that are consistent with the cryptic low-K Fra Mauro chemical component were found, and these appear to be from gabbroic sources. The mineral fragment populations cannot be mixed in their observed proportions to produce the whole rock composition, because the fragments are more refractory and deficient in Ti, P, and alkalis. A preferential contribution to the melt from a rock similar to sodic ferrogabbro can partly resolve the discrepancy. The population of mineral fragments requires a very diverse population of igenous rocks that are not all related to each other, demonstrating the existence of a complex crust built of numerous separate igneous plutons. Many of these plutons may have crystallized at shallow depths. The chemical composition of the melt breccias, in combination with the mineral fragment data and an understanding of the cratering process, suggests that the deepest crust sampled by the Serenitatis impace (not necessarily the deepest crust) was basaltic in composition, including KREEP and gabbroic rocks like sodic ferrogabbro, and lacking abundant olivine-rich material. These were overlain by Mg-suite rocks of varied types, including norites and troctolites that supplied most of the olivine mineral fragments. Granulities, which are metamorphosed and more feldspathic breccias, were abundant near the surface. Remote sensing indicates that the entire Serenitatis region lacks ferroan anorthosite, consistent with the results of our study