Optimal Spacecraft Attitude Controlusing Aerodynamic Torques
This thesis introduces a method of three-axis spacecraft attitude control using only aerodynamic torques. Attitude actuation is achieved using four control panels mounted on the rear of a cubical spacecraft bus. The controller consists of an outer loop using linear state feedback to determine desired control torque and an inner loop to choose appropriate control panel angles. The inner loop uses a Jacobian-based approachto invert the nonlinear relationship between panel angles and generated torque. Controller performance is evaluated via simulations, which show that three-axis control is possible over a range of initial angles and angular rates. The analysis used partial accommodation theory as the basis for aerodynamic torque calculations and assumed a rotating atmosphere with an exponential density profile.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
Analysis and Forecasting of Air Force Operating and Support Cost for Rotary Aircraft
This research explores forecasting techniques to estimate the Cost per Flying Hour for Air Force Helicopters. Specifically, this research evaluates three separate forecasting techniques to predict the CPFH for better estimating and budgeting by the USAF. It starts by empirically analyzing the Operating and Support cost by CAIG categories for each helicopter. For forecasting purposes the actual CPFH figures were compiled from FY96 to FY03 for a total of eight MAJCOMs flying the MH-53J/M, the HH-60G, or the UH-1N helicopters. The research explores the use of a 3-year moving average, the single exponential smoothing method, and the Holt's linear method.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
AFIT UAV Swarm Mission Planning and Simulation System
The purpose of this research is to design and implement a comprehensive mission planning system for swarms of autonomous aerial vehicles. The system integrates several problem domains including path planning, vehicle routing, and swarm behavior. The developed system consists of a parallel, multi-objective evolutionary algorithm-based path planner, a genetic algorithm-based vehicle router, and a parallel UAV swarm simulator. Both the path planner and the UAV swarm simulator are developed on AFIT's Beowulf parallel computer clusters. An extensive set of tests are performed to validate the system components as well as the system integration. Tests focus on two primary objectives: efficiency and effectiveness. The simulator is interfaced with a visualization system that serves as both an iterative design tool and as a mission playback tool. As a design tool, the visualization system provides rapid feedback, allowing developers to quickly observe the effects of model changes on its behavior. As a mission playback tool, decision makers and mission planners can view mission scenarios played out with different sets of parameters. Novel aspects of this research include: integrating terrain following technology into a swarm model as a means of detection avoidance, combining practical problems of path planning and routing into a comprehensive mission planning strategy, and the development of a swarm behavior model with path following capabilities. The culmination of this effort is the development of an extensible developmental model for swarm behavior. Discussions on the of the system's capabilities and limitations are presented along with recommendation for further development.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
Modeling, Stability, and Control of a Rotatable Tail on a Micro Air Vehicle
This research uses existing experimental wind tunnel data to develop a non-linear model that is used to characterize the stability of a flexible wing Micro Air Vehicle (MAV) with a rotatable tail. The experimental data are curve fit based on either angle of attack or angle of sideslip, and the coupled effect of tail rotation and tail deflection on the force and moment coefficients. Static optimization trims the input and state variables for Steady Level Unaccelerated Flight (SLUF). The resulting initial conditions are fed to an open loop non-linear Simulink/Matlab simulation. The study found that the bare MAV design is unstable, but parametric studies identified practical modifications that could be made to the MAV to improve its open loop stability characteristics. The study found that the coupling affect due to the dihedreal derivative, Cl, played a large role in destabilizing the lateral-directional dynamics and a feedback Stability Augmentation System is required for flight.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
Small Internal Combustion Engine Testing for a Hybrid-Electric Remotely-Piloted Aircraft
Efficient operation of a hybrid-electric propulsion system (HEPS) powering a small remotely-piloted aircraft (RPA) requires that a controller have accurate and detailed engine and electric motor performance data. Many small internal combustion engines (ICEs) currently used on various small RPA were designed for use by the recreational hobbyist radio-control (R/C) aircraft market. Often, the manufacturers of these engines do not make accurate and reliable detailed engine performance data available for their engines. A dynamometer testing stand was assembled to test various small ICEs. These engines were tested with automotive unleaded gasoline (the manufacturer's recommended fuel) using the dynamometer setup. Torque, engine speed and fuel flow measurements were taken at varying load and throttle settings. Power and specific fuel consumption (SFC) data were calculated from these measurements. Engine performance maps were generated in which contours of SFC were mapped on a mean effective pressure (MEP) versus engine speed plot. These performance maps are to be utilized for performance testing of the controller and integrated HEPS in further research.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
Micro-Mechanical Voltage Tunable Fabry-Perot Filters Formed in (111) Silicon
The MEMS (Micro-Electro-Mechanical-Systems) technology is quickly evolving as a viable means to combine micro-mechanical and micro-optical elements on the same chip. One MEMS technology that has recently gained attention by the research community is the micro-mechanical Fabry-Perot optical filter. A MEMS based Fabry-Perot consists of a vertically integrated structure composed of two mirrors separated by an air gap. Wavelength tuning is achieved by applying a bias between the two mirrors resulting in an attractive electrostatic force which pulls the mirrors closer. In this work, we present a new micro-mechanical Fabry-Perot structure which is simple to fabricate and is integratable with low cost silicon photodetectors and transistors. The structure consists of a movable gold coated oxide cantilever for the top mirror and a stationary Au/Ni plated silicon bottom mirror. The fabrication process is single mask level, self aligned, and requires only one grown or deposited layer. Undercutting of the oxide cantilever is carried out by a combination of RIE and anisotropic KOH etching of the (111) silicon substrate. Metallization of the mirrors is provided by thermal evaporation and electroplating. The optical and electrical characteristics of the fabricated devices were studied and show promissing results. A wavelength shift of 120nm with 53V applied bias was demonstrated by one device geometry using 6.27 micrometer air gap. The finesse of the structure was 2.4. Modulation bandwidths ranging from 91KHz to greater than 920KHz were also observed. Theoretical calculations show that if mirror reflectivity, smoothness, and parallelism are improved, a finesse of 30 is attainable. The predictions also suggest that a reduction of the air gap to 1 micrometer results in an increased wavelength tuning range of 175 nm with a CMOS compatible 4.75V.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
Common Aero Vehicle Autonomous Reentry Trajectory Optimization Satisfying Waypoint and No-Fly Zone Constraints
To support the Global Strike mission, an autonomous trajectory optimization technique is presented to minimize the flight time, satisfy terminal and intermediate constraints, and remain within the specified vehicle heating and control limitations. "Waypoints" are specified for reconnaissance or multiple payload deployments and "no-fly zones" are specified for geopolitical restrictions or threat avoidance. The Hypersonic Cruise Vehicle (HCV) is used as a simplified two-dimensional platform to compare multiple solution techniques. The solution techniques include a unique geometric approach, an analytical dynamic optimization technique, and a numerical approach. This numerical technique is a direct solution method involving pseudospectral methods and nonlinear programming to converge to the optimal solution. The Common Aero Vehicle (CAV) is used as the test platform for the full three-dimensional reentry trajectory optimization problem. The culmination of this research is the verification of the optimality of this proposed numerical technique, as shown for both the two-dimensional and three-dimensional models. Lastly, user implementation strategies are presented to improve accuracy and enhance solution convergence.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
A Static Aeroelastic Analysis of a Flexible Wing Mini Unmanned Aerial Vehicle
The static aeroelastic behavior of the Nighthawk mini unmanned aerial vehicle is examined using acombined experimental and computational approach. Three wings are examined. In order of increasingstiffness they are: a flexible wing, a stiff wing, and a fictitious rigid wing with zero deflection. Photogrammetryis used during wind tunnel testing to measure the average deflected shape of the flexible and stiff wingsduring flight. The independent variables during wind tunnel tests are angle of attack (ranging from -5.1othrough 13.4o) and velocity, which is 20 mph, 30 mph, and 40 mph. Roll angle and yaw angle are controlvariables, held constant at 0o. The measured deflection of each wing is used to adjust the wing shape forcomputational fluid dynamics analysis. Solutions are obtained for the flexible, stiff, and undeflected (or rigid)wings using a steady-state viscous flow solver with a Spalart-Allmaras turbulence model. The flexible andstiff wings experience two forms of deformation during flight. They bend upward along the span increasingthe dihedral, and the leading edge twists downward (wing washout). The amplitude of deflection is greatestfor the flexible wing. As a result, the flexible wing is more stable, but also exhibits worse static aerodynamicperformance. The rigid wing has the greatest lift (CL max=1.29) and the highest lift-to-drag ratio (L/Dmax =10.2).Stall occurs first near the root for all three wings. None of the wings stall at the tip in the range of angles ofattack tested. A separation bubble forms under the wing at angles of attack less than 8o. This separationdecreases the overall lift. It is most prominent on the flexible wing.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
A Methodology for Simulating the Joint Strike Fighter's (JSF) Prognostics and Health Management System
The Autonomic Logistics System Simulation (ALSim) was developed to provide decision makers a tool to make informed decisions regarding the Joint Strike Fighter's (JSF) Autonomic Logistics System (ALS). The benefit to ALS is that it provides real time maintenance information to ground maintenance crews, supply depots, and air planners to efficiently manage the availability of JSF aircraft. This thesis effort focuses on developing a methodology to model the Prognostics and Health Management (PHM) component of ALS. The PHM component of JSF is what actually monitors the aircraft status. To develop a PHM methodology to use in ALSim a neural network approach is used. Notional JSF prognostic signals were generated using an interactive Java application, which were then used to build and train a neural network. The neural network is trained to predict when a component is healthy and/or failing. The results of the neural network analysis are meaningful failure detection times and false alarm rates. The analysis presents a batching approach to train the neural network, and looks at the sensitivity of the results to batch size and the neural network classification rule used. The final element of the research is implementing the PHM methodology in ALSim.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
The UAV Continuous Coverage Problem
The purpose of this research is to develop a method to find an optimal UAV cyclic schedule to provide maximum coverage over a target area to support an ISR mission. The goal is to reach continuous coverage. UAV continuous coverage of a target area is crucial for the success of an ISR mission. Even the smallest coverage gap may jeopardize the success of the mission. Ideally it is desirable to obtain continuous coverage of a target area but the stochastic nature of the problem makes continuous coverage without gaps unlikely. However, it is still possible to obtain a high coverage rate. Coverage gaps may occur at handoff from one UAV to another. We first study a deterministic model with identical UAVs and derive the minimum number of required UAVs to ensure continuous coverage. Continuous coverage is possible only in the deterministic setting. The model provides valuable insights on the parameters driving the UAV performance coverage. It is shown that the loitering and the roundtrip times are the most impacting parameters driving the performance coverage of the UAVs. It is proved that the number of UAVs is an increasing function of the roundtrip time and a decreasing function of the loitering time.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
Description and Sampling of Contaminated Soils
The U.S. Environmental Protection Agency (EPA) was introduced on December 2, 1970 by President Richard Nixon. The agency is charged with protecting human health and the environment, by writing and enforcing regulations based on laws passed by Congress. The EPA's struggle to protect health and the environment is seen through each of its official publications. These publications outline new policies, detail problems with enforcing laws, document the need for new legislation, and describe new tactics to use to solve these issues. This collection of publications ranges from historic documents to reports released in the new millennium, and features works like: Bicycle for a Better Environment, Health Effects of Increasing Sulfur Oxides Emissions Draft, and Women and Environmental Health.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
Development of a Flapping Wing Design Incorporating Shape Memory Alloy Actuation
This research sought to validate a proof of concept regarding shape memory alloy actuation of a flapping-wing blimp. Specimen wires were subjected to cyclic voltage at increasing frequencies to quantify expected strains. A laser vibrometer captured 2048 sample velocities during single contraction and elongation cycles, and the resulting samples were used to calculate displacements. Displacements were determined ten times for each specimen and frequency to compute averages. Subsequently, a circumventing frame was designed to encase a blimp envelope and provide support for a flapping motion actuation system. Contraction of shape memory wire translated force to the flapping mechanism via bellcranks, pushrods, and clevises, while bias springs promoted elongation of the wire during power-off phases. Performance characteristics of the flapping system, augmented with each specimen wire individually, were determined during bench-top testing. A modified frame was constructed to reduce weight and fitted to a larger envelope due to buoyancy limitations of the original envelope. A circuit was constructed, cycling voltage at 0.2 hertz, to actuate the specimen wires. Performance of the system was observed with the incorporation of each specimen. Optimum performance was realized with the 0.005 inch diameter specimen wire, producing 25 to 35 degrees wing deflection.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
Building a Better Aircraft Maintenance Officer
Several changes have occurred in the maintenance operating environment and in aircraft maintenance officer training and development activities since the last known academic review in 2002.1 Chief among them are the reorganization of the wing structure into the Combat Wing Organization; creation of the 21AX Career Field Education and Training Plan (CFETP), the Maintenance Officer Intermediate Course (MOIC), and the Advanced Maintenance and Munitions Officer's School (AMMOS); as well as the introduction of the 21A/M Developmental Team (DT). In addition, several changes in the national security environment, including the DoD basing structure and the type of wars we fight, continue to shape the maintenance environment.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
USAF Pilot Perceptions of Workload Assessment in a Combat or High-Threat Environment
This study analyzed the self-reported survey responses of 219 Air Force Pilots concerning their perceptions of workload assessment in a combat or a high-threat environment. The first objective of this study was to determine and compare the combat workload factors of varying importance in combat workload assessment by aircraft and mission type flown. The second objective was to examine the pilots' perception of combat mission in-flight workload. A stepwise regression model to predict the pilots' perceptions of in-flight workload using pilots' characteristic data was explored. Research conclusion varied among aircraft types. Combat workload items indicated, as "distractingly" important were similar for all aircraft types, while items in lower level of importance were impacted by aircraft type. Mean Combat Workload (CWL) scores of pilots from each aircraft type were not significantly different. Overall, it was concluded that surveying pilots who had flown in combat or high-threat environments provided useful responses to assess pilot workload; however, findings based on subjective assessments, provide tentative grounds for further research.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
Reliability and Productivity Modeling for the Optimization of Separated Spacecraft Interferometers
As technological systems grow in capability, they also grow in complexity. Due to this complexity, it is no longer possible for a designer to use engineering judgement to identify the components that have the largest impact on system life cycle metrics, such as reliability, productivity, cost, and cost effectiveness. One way of identifying these key components is to build quantitative models and analysis tools that can be used to aid the designer in making high level architecture decisions. Once these key components have been identified, two main approaches to improving a system using these components exist: add redundancy or improve the reliability of the component. In reality, the most effective approach to almost any system will be some combination of these two approaches, in varying orders of magnitude for each component. Therefore, this research tries to answer the question of how to divide funds, between adding redundancy and improving the reliability of components, to most cost effectively improve the life cycle metrics of a system. While this question is relevant to any complex system, this research focuses on one type of system in particular: Separate Spacecraft Interferometers (SSI). Quantitative models are developed to analyze the key life cycle metrics of different SSI system architectures. Next, tools are developed to compare a given set of architectures in terms of total performance, by coupling different life cycle metrics together into one performance metric. Optimization tools, such as simulated annealing and genetic algorithms, are then used to search the entire design space to find the "optimal" architecture design. Sensitivity analysis tools have been developed to determine how sensitive the results of these analyses are to uncertain user defined parameters. Finally, several possibilities for the future work that could be done in this area of research are presented.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
Systems-Level Feasibility Analysis of a Microsatellite Rendezvous With Non-Cooperative
The United States is very dependant upon the use of space. Any threat to our ability to use it as desired deserves significant study. One such asymmetric threat is through the use of a microsatellite. The feasibility of using a microsatellite to accomplish an orbital rendezvous with a non-cooperative target is being evaluated. This study focused on identifying and further exploring the technical challenges involved in achieving a non-cooperative rendezvous. A systems engineering analysis and review of past research quickly led to a concentration on the guidance, navigation, and control (GNC) elements of the microsatellite operation. While both the control laws and orbit determination have been previously evaluated as feasible, the integration of the two remained in question. This research first validated past efforts prior to exploring the integration. Impulsive and continuous thrust control methods, and linear and nonlinear estimator filters were all candidate components to a potential system solution. A simple yet robust solution could not be found to meet reasonable rendezvous criteria, using essentially off-the-shelf technology and algorithms. Results reveal a simple linear filter is a misapplication and will not at all work. A nonlinear filter coupled with either a continuous or impulsive thrust controller was found to get somewhat close, but never close enough to attach to the target satellite. Successful GNC subsystem integration could only be achieved for a very simple case ignoring orbit perturbations such as the earth's oblateness. A top-level system architecture for a non-cooperative rendezvous microsatellite has been developed. The technical complexity, however, requires more complex algorithms to solve the rendezvous problem.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
Integrating Automated Multi-Disciplinary Optimization in Preliminary Design of Non-Traditional Aircraft
Current methods of aircraft conceptual design lack the ability to quickly generate detailed analysis, particularly of nontraditional designs such as blended wing body craft. This study developed a method to resolve this problem by creating a flexible, parametrically driven conceptual model in an object-oriented, adaptive modeling environment from which analysis and optimization may rapidly be performed. These object-oriented techniques are incorporated into a traditional conceptual design process. All objects inherit dependency-tracking and demand-driven calculations. Design Analysis was performed within the modeling language and utilized interfaces to other software packages. A detailed mesh, suitable for input into finite element analysis programs, was developed from the less detailed, geometric mesh created by the modeling program. The output from finite element analysis forms the basis for rapid changes in subsequent iterations of the design process. The demonstration focuses on a single parametric design model which transforms a conventional transport design into a blended wing body design. This single design is controlled by a limited set of geometric variables and produces optimal structural weight estimations while the designer addresses volumetric and cost requirements.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
Handling Qualities Evaluation of a Supersonic Tailless Air Vehicle
This thesis presents the results of a handling qualities evaluation of a supersonic tailless air vehicle. The 2006 Quadrennial Defense Review mandated the need for the next generation of long-range strike aircraft by 2018. Due to speed and stealth requirements, this resulted in a tailless aircraft with an instantaneous center of rotation located well forward of that of a conventional aircraft. This thesis examines how this center of rotation affected pilot handling qualities ratings. This effect should have been the most pronounced during approach and landing, and was where the testing focused. The goal of this research was to develop a systematic procedure for evaluating the handling qualities of this aircraft, and to determine how different pilot flying techniques or pilot-inceptor interactions influenced them. This procedure was demonstrated in simulator testing and in flight testing on the Calspan-operated Total In-Flight Simulator aircraft.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
Spacecraft Proximity Operations Used to Estimate the Dynamical and Physical Properties of a Resident Space Object
When conducting a space proximity operation, developing high-fidelity estimates of the dynamical and physical properties of a Resident Space Object (RSO)based on post-rendezvous observational data acquired, is imperative for the understanding of the RSO itself and the operating environment. This research investigatesthe estimation of relative motion dynamics, rotational dynamics, and the feasibilityof estimating the moments of inertia of a RSO. Using the Hill-Clohessy-Wiltshire equations, rigid-body dynamics, and estimation theory, a nonlinear least squaresestimation algorithm is implemented in the processing of range data from tracked observation points on the RSO body. Through simulation, it was determined that accurately estimating the relative motion and rotational dynamics is possible. However directly estimating the moments of inertia using range data proved to be problematicand exposed a possible observability limitation. Yet in general, the solutions were heavily dependent on the quality of the a priori knowledge as well as the reduction of solution ambiguity through the use of multiple observational data sets.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
Cubesat Packaged Electrospray Thruster Evaluation for Enhanced Operationally Responsive Space Capabilities
A new specialized electrospray thruster with a potential to be used with a 3-U CubeSat was operated. The key difference in this thruster from traditional colloid thrusters is the porous stainless steel surface used for the emission sites. With this porous surface the actual location and number of the Taylor cones formations vary with changing fuel flow. The understanding of these formations is discussed with low, moderate, and high flow rates. The limitations of the experiment and observed system response are discussed. Due to these limitations, the colloid thruster was only able to operate in the low mass flow rate regime.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
Detonation Propagation Through Ducts in a Pulsed Detonation Engine
Development of a continuously operating pulsed detonation engine (PDE) without a high energy ignition system or a deflagration-to- detonation transition (DDT) device will increase engine efficiency, reduce cost, improve performance, and reduce weight. This report is a study of configurations that allow a consistent and predictable transition of a detonation from one detonation tube to second tube. The intent was, via visualization of detonation propagation through a cross-over tube, to develop a cross-over passage leading to minimization of energy losses and effective and repeatable tube-to-tube initiation. Detonation tube cross-over width, cross-over geometry and fuels were varied to determine their effect on tube-to-tube detonation initiation. The cross-over detonations studied decoupled into and out of the cross-over tube due to propagation as subcritical spherical detonations. It was shown that the mechanism of shock reflection could be used to transition the spherical detonation back to a planar detonation.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
Controlling Sideslip Angle to Reduce the Radar Exposure of a Tactical, Rotary Winged UAV
This work investigates another way of contributing to the radar minimization solution for air vehicles in a threat environment. While muchresearch has been conducted on structural solutions to radar exposure minimization, not much work has been done in the area of using control tocontinuously assess and present the smallest radar cross section of an air vehicle to oncoming threat radar systems by changing the aircraft'sorientation. This work looks at the application of sideslip/beta angle feedback control of an unmanned helicopter to minimize radar crosssection exposure in a hostile radar environment. A new way of controlling aircraft trajectory is introduced that incorporates both path andorientation optimization feedback; the aircraft's heading is controlled to orient the vehicle in a way that reduces its radar cross section, whilesideslip angle is used to control the aircraft's path. A representative hostile environment is created and results show that a substantial reductionin radar cross section exposure can be achieved with beta feedback control. A linear state space model is derived for the OH-6A helicopter withthe JANRAD software program. Eigenstructure assignment is used to shape the response of the helicopter into desired response modes. AMatlab based flight control system is developed around the derived helicopter model with altitude, heading, and beta angle command signalsthat drive four conventional helicopter control inputs.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
Rockets and People, Volume 2
Much has been written in the West on the history of the Soviet space program but few Westerners have read direct first-hand accounts of the men and women who were behind the many Russian accomplishments in exploring space. The memoirs of Academician Boris Chertok, translated from the original Russian, fills that gap. In these writings, spread over four volumes, Chertok not only describes and reflects upon his experiences, but he also elicits and extracts profound insights from an epic story about a society's quest to explore the cosmos.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
Design of a Space-Borne Autonomous Infrared Tracking System
Complete characterization of the space environment in support of the United States' goal of Space Situational Awareness is not currently achievable. When confronted with recent increases in the deployment and miniaturization of microsatellites by numerous nations, the questions of foreign space capabilities are magnified. This study sought to determine the feasibility of and experimentally demonstrate a microsatellite capability to autonomously loiter about and track a target satellite. Various methods of passive remote sensing were investigated to determine the best means of detecting and tracking a target in space. Microbolometer-based infrared sensors were identified as the best sensor for several reasons, primarily due to their ability to track in the absence of light. A representative system was constructed for demonstration in AFIT's SIMSAT laboratory. Software modeling results identified open-loop instability, and therefore the requirement for closed-loop control. A simple PD control algorithm served as the basis for control, and a pseudo-feed-forward term was added to improve the results. The feed-forward term was derived form orbital dynamics as the rate at which the chase satellite traverses around an ellipse formed in the target's frame of reference. Reduction in pointing errors of up to 67% were found in simulations. Non-optimal yet successful tracking results were obtained in the laboratory with a hardware-in-the-loop model for both step and moving inputs. With minor modification, this infrared tracking system could be implemented onboard a microsatellite.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
Modeling of Wake-vortex Aircraft Encounters
There are more people passing through the world's airports today than at any other time in history. With this increase in civil transport, airports are becoming capacity limited. In order to increase capacity and thus meet the demands of the flying public, the number of runways and number of flights per runway must be increased. In response to the demand, the National Aeronautics and Space Administration (NASA), in conjunction with the Federal Aviation Administration (FAA), airport operators, and the airline industry are taking steps to increase airport capacity without jeopardizing safety. Increasing the production per runway increases the likelihood that an aircraft will encounter the trailing wake-vortex of another aircraft. The hazard of a wake-vortex encounter is that heavy load aircraft can produce high intensity wake turbulence, through the development of its wing-tip vortices. A smaller aircraft following in the wake of the heavy load aircraft will experience redistribution of its aerodynamic load. This creates a safety hazard for the smaller aircraft. Understanding this load redistribution is of great importance, particularly during landing and take-off. In this research wake-vortex effects on an encountering 10% scale model of the B737-100 aircraft are modeled using both strip theory and vortex-lattice modeling methods. The models are then compared to wind tunnel data that was taken in the 30ft x 60ft wind tunnel at NASA Langley Research Center (LaRC). Comparisons are made to determine if the models will have acceptable accuracy when parts of the geometry are removed, such as the horizontal stabilizer and the vertical tail. A sensitivity analysis was also performed to observe how accurately the models could match the experimental data if there was a 10% error in the circulation strength. It was determined that both models show accurate results when the wing, horizontal stabilizer, and vertical tail were a part of the geometry. When the horizontal stabilizThis work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
Satellite Capabilities Mapping
The cost and schedule advantages small satellites have over larger legacy systems have been studied, but there has been very little experimentation performed to determine whether small satellites can actually deliver the capabilities of larger spacecraft. To date, a desired operational capability has not been fully realized by a scalable satellite design. Advances in sensor technology have led to significant reductions in size, weight, and power (SWaP) presenting an opportunity to exploit the evolution of space operations by using small satellites to perform specific missions. This paper describes a methodology that maps a specific set of large space vehicle capabilities to CubeSats. The process examines the utility of advanced sensors.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
Costs of Arsenic Removal Technologies for Small Water Systems
The U.S. Environmental Protection Agency (EPA) was introduced on December 2, 1970 by President Richard Nixon. The agency is charged with protecting human health and the environment, by writing and enforcing regulations based on laws passed by Congress. The EPA's struggle to protect health and the environment is seen through each of its official publications. These publications outline new policies, detail problems with enforcing laws, document the need for new legislation, and describe new tactics to use to solve these issues. This collection of publications ranges from historic documents to reports released in the new millennium, and features works like: Bicycle for a Better Environment, Health Effects of Increasing Sulfur Oxides Emissions Draft, and Women and Environmental Health.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
Experimental Investigation of the Flow Field in a Transonic, Axial Flow Compressor With Respect to the Development of Blockage and Loss
A detailed experimental investigation to understand and quantify the development of loss and blockage in the flow field of a transonic, axial flow compressor rotor has been undertaken. Detailed laser anemometer measurements were acquired upstream, within, and downstream of a transonic, axial compressor rotor operating at design and off-design conditions. The rotor was operated at 100%, 85%, 80%, and 60% of design speed which provided inlet relative Mach numbers at the blade tip of 1.48, 1.26, 1.18, and 0.89 respectively. At design speed the blockage is evaluated ahead of the rotor passage shock, downstream of the rotor passage shock, and near the trailing edge of the blade row. The blockage is evaluated in the core flow area as well as in the casing endwall region. Similarly at pm speed conditions for the cases of (1) where the rotor passage shock is much weaker than that at design speed and (2) where there is no rotor passage shock, the blockage and loss are evaluated and compared to the results at design speed. Specifically, the impact of the rotor passage shock on the blockage and loss development, pertaining to both the shock/boundary layer interactions and the shock/tip clearance flow interactions, is discussed. In addition, the blockage evaluated from the experimental data is compared to (1) an existing correlation of blockage development which was based on computational results, and (2) computational results on a limited basis. The results indicate that for this rotor the blockage in the endwall region is 2-3 times that of the core flow region and the blockage in the core flow region more than doubles when the shock strength is sufficient to separate the suction surface boundary layer. The distribution of losses in the care flow region indicate that the total loss is primarily comprised of the shock loss when the shock strength is not sufficient to separate the suction surface boundary layer.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
Design Manual
The U.S. Environmental Protection Agency (EPA) was introduced on December 2, 1970 by President Richard Nixon. The agency is charged with protecting human health and the environment, by writing and enforcing regulations based on laws passed by Congress. The EPA's struggle to protect health and the environment is seen through each of its official publications. These publications outline new policies, detail problems with enforcing laws, document the need for new legislation, and describe new tactics to use to solve these issues. This collection of publications ranges from historic documents to reports released in the new millennium, and features works like: Bicycle for a Better Environment, Health Effects of Increasing Sulfur Oxides Emissions Draft, and Women and Environmental Health.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
A Robust Rotorcraft Flight Control System Design Methodology Utilizing Quantitative Feedback Theory
Rotorcraft flight control systems present design challenges which often exceed those associated with fixed-wing aircraft. First, large variations in the response characteristics of the rotorcraft result from the wide range of airspeeds of typical operation (hover to over 100 kts). Second, the assumption of vehicle rigidity often employed in the design of fixed-wing flight control systems is rarely justified in rotorcraft where rotor degrees of freedom can have a significant impact on the system performance and stability. This research was intended to develop a methodology for the design of robust rotorcraft flight control systems. Quantitative Feedback Theory (QFT) was chosen as the basis for the investigation. Quantitative Feedback Theory is a technique which accounts for variability in the dynamic response of the controlled element in the design robust control systems. It was developed to address a Multiple-Input Single-Output (MISO) design problem, and utilizes two degrees of freedom to satisfy the design criteria. Two techniques were examined for extending the QFT MISO technique to the design of a Multiple-Input-Multiple-Output (MIMO) flight control system (FCS) for a UH-60 Black Hawk Helicopter. In the first, a set of MISO systems, mathematically equivalent to the MIMO system, was determined. QFT was applied to each member of the set simultaneously. In the second, the same set of equivalent MISO systems were analyzed sequentially, with closed loop response information from each loop utilized in subsequent MISO designs. The results of each technique were compared, and the advantages of the second, termed Sequential Loop Closure, were clearly evident.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
Analyzing Carbohydrate-Based Regenerative Fuel Cells as a Power Source for Unmanned Aerial Vehicles
Based on current capabilities, we examine the feasibility of creating a carbohydratebased regenerative fuel cell (CRFC) as the primary power source for unmanned aerial vehicles (UAV) for long endurance missions where station keeping is required. A CRFC power system is based on a closed-loop construct where carbohydrates are generated from zooxanthellae, algae that create excess carbohydrates during photosynthesis. The carbohydrates are then fed to a carbohydrate fuel cell where electric power is generated for the UAV's propulsion, flight control, payload, and accessory systems. The waste products from the fuel cell are used by the zooxanthellae to create more carbohydrates, therefore mass is conserved in the process of power generation. The overall goal of this research is to determine if CRFCs should be explored further as a viable power source. Through simulations, a UAV is sized to determine if greater than 24 hour endurance flight is possible and these results are compared to UAVs using more traditional photocell based power systems. The initial results suggest that more research should be done in the development of CRFCs as a power system for long endurance UAVs. The final outcome of this research is to identify the most important areas for more detailed followon work in designing a production-ready CRFC power system for long endurance UAVs.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
Operational Characteristics of a Rotating Detonation Engine Using Hydrogen and Air
Rotating detonation engines (RDE) are pressure gain combustion engines that have the potential for greater efficiency than traditional, constant pressure, deflagration engines. RDEs are smaller and mechanically simpler than pulsed detonation engines. A small diameter (3 in) engine was successfully run on hydrogen and air. Most of the tests were conducted using air with a slightly lower diluents percentage (77% nitrogen as opposed to 79% nitrogen). These tests provided the foundation for determining the operational space (mass flow rate and equivalence ratio) of the rotating detonation engine. From the tests conducted with the lower diluents air, the appropriate run conditions for regular air were determined. For standard air (79% nitrogen) it was found that a larger equivalence ratio (about 1.5) was required to obtain continuous detonations.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
Long Term Quadrotor Stabilization
The work of this thesis focuses on the IMU and getting the best performance possible out of the IMU to achieve better long term stability and a better navigation solution. This is done in two ways. First, the IMU accelerometer output is examined to determine if it is possible to use accelerometers to determine attitude. If the quadrotor is stationary or moving at constant velocity, the roll and pitch angles can be determined. Additionally, the accelerometers can be used to determine angular accelerations and angular rates which are integrated to determine heading. The second approach models the quadrotor and uses the models in Kalman Filters along with the IMU measurements to determine the best possible navigation solution.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
Sizing Analysis for Aircraft Utilizing Hybrid-Electric Propulsion Systems
Current conceptual aircraft design methods use historical data to predict and evaluate the size and weight of new aircraft. These traditional design methods have been ineffective to accurately predict the weight or physical dimensions of aircraft utilizing unique propulsion systems. The mild hybrid-electric propulsion system represents a unique design that has potential to improve fuel efficiency and reduce harmful emissions. Hybrid-electric systems take advantage of both reliable electric power and the long range/endurance capabilities of internal combustion engines. Desirable applications include general aviation single-engine aircraft and remotely-piloted aircraft. To demonstrate the advantages of mild hybrid-electric propulsion, a conceptual design code was created that modified conventional methods. Using several case studies, the mild hybrid conceptual design tool verified potential fuel savings for general aviation aircraft and expanded mission capability for remotely-piloted aircraft.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
A Novel Communications Protocol Using Geographic Routing for Swarming UAVs Performing a Search Mission
This research develops the UAV Search Mission Protocol (USMP) for swarming UAVs and determines the protocol's effect on search mission performance. It is hypothesized that geographically routing USMP messages improves search performance by providing geography-dependent data to locations where it impacts search decisions. It is also proposed that the swarm can use data collected by the geographic routing protocol to accurately determine UAV locations and avoid sending explicit location updates. The hypothesis is tested by developing several USMP designs that are combined with the Greedy Perimeter Stateless Routing (GPSR) protocol and a search mission swarm logic into a single network simulation. The test designs use various transmission power levels, sensor types and swarm sizes. The simulation collects performance metrics for each scenario, including measures of distance traveled, UAV direction changes, number of searches and search concentration. USMP significantly improves mission performance over scenarios without inter-UAV communication. However, protocol designs that simply broadcast messages improve search performance by 83% in total searches and 20% in distance traveled compared to geographic routing candidates. Additionally, sending explicit location updates generates 3%-6% better performance per metric versus harvesting GPSR's location information.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
Wind Tunnel Analysis and Flight Test of a Wing Fence on a T-38
A low-speed wind tunnel study and flight tests were performed to examine the effects of a wing fence on the T-38A. Wind tunnel results were based upon force and moment data collected with a six-component balance and flow visualization at Reynolds numbers up to 0.3 x 106, based on mean aerodynamic chord. The model did not include the last 7.79 feet of the aircraft, and the engine and exhaust were modeled as through-holes. Five fence geometries, placed at wing station 125 ( 0.825 semispan), were compared. The best performer of these designs, based on drag polar, was the fence that wrapped the leading edge and extended 84.6 percent of the local chord length along the wing's upper surface. Wind tunnel data showed that this fence increased the lift coefficient by up to 6.3 0.6 percent and reduced spanwise and separated flow outboard the fence. The flight-tested fence was based on the best performing fence design from the wind tunnel study. The results were based on aircraft instrumentation and flow visualization at Reynolds numbers up to 9.98 x 106. It was inconclusive whether the fence caused an increase in lift coefficient. The fence reduced the roll-off tendency and wing rock during approaches to stall. Tuft visualization on the aircraft wing suggested that the fence reduced spanwise and separated flow outboard the fence, which agreed with the wind tunnel results.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
A Comparative Analysis of the Cost Estimating Error Risk Associated With Flyaway Costs Versus Individual Components of Aircraft
A shrinking workforce, unstable budgets, and rapidly changing objectives under stricter time constraints characterize today's cost analysis and acquisition environment. In concert with this environment, cost analyst positions have rapidly decreased as demonstrated by Aeronautical Systems Centers 54% decline in total authorized slots from 1992 to 2001. The question is how to deal with this 'more with less' mentality.The purpose of this research is to investigate and measure the risks associated with taking a macro versus micro approach to aircraft cost estimation. By analyzing the fidelity of a cost estimate developed at the flyaway cost level versus a cost estimate developed at the individual components level, this research provides guidelines for appropriate allocation of cost analyst resources. This objective is accomplished by looking at the cost estimation error risk of recurring costs at level one of the Work Breakdown Structure (WBS) and at level two of the WBS.Results show that there is a statistically significant difference between estimating at the differing WBS levels. However, from a practical standpoint, the difference in dollar terms is too small to be considered significant. As a result, program manager should allocate resources based on other constraints such as time allotted to complete the estimate or required level of visibility into the estimate.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
Experimental Methods to Characterize Nonlinear Vibration of Flapping Wing Micro Air Vehicles
For urban combat reconnaissance, the flapping wing micro air vehicle concept is ideal because of its low speed and miniature size, which are both conducive to indoor operations. The focus of this research is the development of experimental methods best suited for the vibration testing of the wing structure of a flapping wing micro air vehicle. This study utilizes the similarity of a beam resonating at its first bending mode to actual wing flapping motion. While computational finite element analysis based on linear vibration theory is employed for preliminary beam sizing, an emphasis is placed on experimental measurement of the nonlinear vibration characteristics introduced as a result of large movement. Beam specimens fabricated from 2024-T3 aluminum alloy and IM7/5250-4 carbon epoxy were examined using a high speed optical system and a scanning laser vibrometer configured in both three and one dimensions, respectively.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
Optimizing Mean Mission Duration for Multiple-Payload Satellites
This thesis addresses the problem of optimally selecting and specifying satellite payloads for inclusion on a satellite bus to be launched into a constellation. The objective is to select and specify payloads so that the total lifetime utility of the constellation is maximized. The satellite bus is limited by nite power, weight, volume, and cost constraints. This problem is modeled as a classical knapsack prob- lem in one and multiple dimensions, and dynamic programming and binary integer programming formulations are provided to solve the problem. Due to the compu- tational complexity of the problem, the solution techniques include exact methods as well as four heuristic procedures including a greedy heuristic, two norm-based heuristics, and a simulated annealing heuristic. The performance of the exact and heuristic approaches is evaluated on the basis of solution quality and computation time by solving a series of notional and randomly-generated problem instances. The numerical results indicate that, when an exact solution is required for a moderately- sized constellation, the integer programming formulation is most reliable in solving the problem to optimality. However, if the problem size is very large, and near- optimal solutions are acceptable, then the simulated annealing algorithm performs best among the heuristic procedures.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
Autonomous Air Refueling for Unmanned Aircraft Systems
Air Refueling (AR) demonstrates its critical importance on a daily basis in combat and peacetime missions all over the world. It is a crucial link enabling the global reach the US Air Force needs to fly, fight and win the current Global War on Terrorism (GWOT) and conduct various other missions in support of the US Military Strategy. Despite its critical importance to airpower, AR technology has changed little in the last 50 years. The Air Force uses the same basic refueling systems designed for Strategic Air Command (SAC) over a half-century ago. These systems require a heavy workload by the receiver pilot either maintaining position in a tight refueling envelope for the Boom System or actually making and maintaining a contact with the Probe and Drogue System. With unmanned platforms playing a larger role in the Intelligence, Surveillance and Reconnaissance (ISR) role and envisioned to one day replace the manned fighter, a system which can accomplish air refueling autonomously is being sought to enable the next generation of combat and ISR aircraft to safely conduct AR. The purpose of this research is to accomplish a cost/benefit analysis of air refueling Unmanned Aircraft Systems (UAS) used as ISR platforms, specifically high altitude endurance (HAE) class UAS such as the Global Hawk. Currently two different AAR systems are being developed and tested independently by the Air Force Research Lab (AFRL) and the Defense Advanced Research Projects Agency (DARPA) in conjunction with the Sierra Nevada Corporation. This research is not intended to determine the superiority of one system over the other however; it is only intended to weigh the benefits and costs of the AAR concept as a whole.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
Automated Carrier Landing of an Unmanned Combat Aerial Vehicle Using Dynamic Inversion
Dynamic Inversion (DI) is a powerful nonlinear control technique which has been applied to several modern flight control systems. This research utilized concepts of DI in order to develop a controller to land an Unmanned Combat Aerial Vehicle (UCAV) on an aircraft carrier. The Joint Unmanned Combat Air System (J-UCAS) Equivalent Model was used as the test aircraft. An inner-loop DI controller was developed to control the pitch, roll, and yaw rate dynamics of the aircraft, while an outer-loop DI controller was developed to provide flight path commands to the inner-loop. The controller design and simulation were conducted in the MATLABR-/Simulink R- environment. Simulations were conducted for various starting positions near the carrier and for varying wind, wind turbulence, and sea state conditions. In the absence of wind and sea state turbulence, the controller performed well. After adding wind and sea state turbulence, the controller performance was degraded. Future work in this area should include a more robust disturbance rejection technique to compensate for wind turbulence effects and a method of carrier motion prediction to compensate for sea state effects.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
Comparing Risks From Low-Level Radioactive Waste Disposal on Land and in the Ocean a Review of Agreements/Statutes, Scenarios, Processing/Packaging/Disposal Technologies, Models, and Decision Analysis
The U.S. Environmental Protection Agency (EPA) was introduced on December 2, 1970 by President Richard Nixon. The agency is charged with protecting human health and the environment, by writing and enforcing regulations based on laws passed by Congress. The EPA's struggle to protect health and the environment is seen through each of its official publications. These publications outline new policies, detail problems with enforcing laws, document the need for new legislation, and describe new tactics to use to solve these issues. This collection of publications ranges from historic documents to reports released in the new millennium, and features works like: Bicycle for a Better Environment, Health Effects of Increasing Sulfur Oxides Emissions Draft, and Women and Environmental Health.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
Fixed-Wing Aircraft Combat Survivability Analysis for Operation Enduring Freedom and Operation Iraqi Freedom
The primary tenet of the aircraft survivability discipline is threat definition. In order to deliver relevant capabilities and protection to the warfighter it is imperative; therefore, to provide timely, accurate, and actionable threat data to the survivability community. In an attempt to identify the evolution of aircraft threats in today's combat environment, an analysis of fixed-wing aircraft battle damage was conducted. This analysis reports battle damage incidents from OPERATIONS ENDURING FREEDOM (OEF) and IRAQI FREEDOM(OIF). Additionally, reported damage incidents were then validated by crosschecking aircraft maintenance records from this period to eliminate non-hostile fire data points. This revolutionary approach uncovered discontinuities, which were further explored to identify their root cause. As a result, significant Air Force policy changes in the realm of battle damage reporting procedures were suggested. In the end, lives will be saved because the acquisition community at large will have valuable threat data in which they can be confident.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
Measurement of Human Pilot Dynamic Characteristics in Flight Simulation
Fast Fourier Transform (FFT) and Least Square Error (LSE) estimation techniques were applied to the problem of identifying pilot-vehicle dynamic characteristics in flight simulation. A brief investigation of the effects of noise, input bandwidth and system delay upon the FFT and LSE techniques was undertaken using synthetic data. Data from a piloted simulation conducted at NASA Ames Research Center was then analyzed. The simulation was performed in the NASA Ames Research Center Variable Stability CH-47B helicopter operating in fixed-basis simulator mode. The piloting task consisted of maintaining the simulated vehicle over a moving hover pad whose motion was described by a random-appearing sum of sinusoids. The two test subjects used a head-down, color cathode ray tube (CRT) display for guidance and control information. Test configurations differed in the number of axes being controlled by the pilot (longitudinal only versus longitudinal and lateral), and in the presence or absence of an important display indicator called an 'acceleration ball'. A number of different pilot-vehicle transfer functions were measured, and where appropriate, qualitatively compared with theoretical pilot- vehicle models. Some indirect evidence suggesting pursuit behavior on the part of the test subjects is discussed.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
Feature Selection for Predicting Pilot Mental Workload
As advances in technology are made, the cockpits of the aircraft in the Air Force inventory have become increasingly complex. Consequently, mental demands on the pilot have risen. In a worst case scenario, the pilots have been so saturated with inputs they have actually forgotten to carry out the fundamentals of flying, such as G-straining maneuvers, resulting in several fatalities. Recent research in this area has involved collecting psychophysioloical features, such as electroencephalography (EEG), heart, eye and respiration measures, in an attempt to identify pilot mental workload. This thesis focuses on feature selection and reduction of the psychopnysiological features and subsequent classification of pilot mental workload on multiple subjects over multiple days. A stepwise statistical technique and the signal-to-noise (SNR) saliency metric were used to reduce the number of features required for classification. Factor analysis was used to compare the variables chosen by the discriminant procedure and the SNR saliency metric as applied to a neural network.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
Concepts of Operations for a Reusable Launch Space Vehicle
The US military must be prepared to take advantage of reusable launch vehicles should the NASA-led effort to develop an RLV demonstrator prove successful. The focus of this research was an explanation of how the US military could use RLVs by describing and analyzing two concepts of operations. Four assumptions which guided the research are worthy of mention. First, the estimate that RLV technology will become operationally feasible by 2012 is reasonable. Second, a fiscally constrained environment will continue. Third, the US government will continue to support growth and development of the US commercial spacelift industry and encourage dual-use, or perhaps triple-use, of related facilities and systems. Fourth, the US Government's national security strategy will continue to emphasize international leadership and engagement to further its political, economic, and security objectives.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
A Systems Engineering Approach to the Design of a Spacecraft Dynamics and Control Testbed
A systems engineering team used an innovative process to develop a new frictionless air bearing satellite simulator, SIMSAT II, for AFIT. AFIT faculty provided the design team with initial requirements, including rotating 30 rpm for spin stabilization and a rapid slewing capability about the yaw axis of +/- 45 degrees in 15 seconds from a standing start to a standing stop. The design team developed the Project Vee process model to meet these requirements by combining key system engineering principles of the original Vee model with project management tenets. The Project Vee model decomposed the requirements to produce a complete system design, guided the procurement of components, and performed validation and verification of the system. The design effort resulted in a three-axis, tabletop spherical air bearing configuration. SIMSAT II incorporates the use of fans as an actuating device for rapid slewing capability, a rigid structure for greater stability, and the capability for longer experimental runs. A modular payload platform allows for numerous types of experiments to be conducted onboard the system. SIMSAT II provides AFIT with a new simulator for spacecraft dynamics and control, with both educational and research experimentation possibilities.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
Thomson Scattering Study of Collisional-Shock Heated Plasmas, Report No. 62
Thomson scattering was used to obtain eloctron temperature and density profiles in deuterium plasmas produced by strong collisional shock waves. The transverse shock speeds were 3 to 25 cm/ usec in 50 to 100 mTorr deuterium. Ruby laser light was incident at a right angle to the axis in the midpoint of the annular gap of an electromagnetically driven coaxial shock tube.and scattered 9 light was collected at 90 degrees. Plasma created by reflecting a strong shock from a dielectric wall was also studied. It is found that the plasma electron temperature (10-30 eV) is much less than the ion temperature (100-500 eV) as is predicted by theory for the early life of theplasma. Electron-lon Coulomb colllslonal temperature relaxation does not occur during the times of observation (3-4, AA sec). Electron heating in the plasma is caused primarily by Ohmic dissipation of currents in the shock structure and piston. Plasma densities (0.5-3.5x1016 cm-3)agree well with shock theory predictions. For gas ionizing shocks, good agreement with collisional theory is found for the electron temperature.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
