Aerospace Engineering Commons^™

Effects Of Uncertainty Refinement On Satellite Collision Probability, Bruce Thomas Morrison

Masters Theses

"Due to the drastic increase in orbital debris about the Earth, the likelihood for new and current mission satellites to collide with other objects grows. When a mission satellite is placed in a highly populated orbit in the vicinity of other satellites or debris, it is necessary to consider the probability of collision to assess any possible conjunctions. The computation of the collision probability is heavily dependent on the relative position and velocity of the objects during conjunction, as well as the combined covariance. There are two main types of analytic collision probability computations; the first assumes that the objects …

Program Management For Concurrent University Satellite Programs, Including Propellant Feed System Design Elements, Shannah Withrow-Maser

Masters Theses

"Propulsion options for CubeSats are limited but are necessary for the CubeSat industry to continue future growth. Challenges to CubeSat propulsion include volume/mass constraints, availability of sufficiently small and certified hardware, secondary payload status, and power requirements. A multi-mode (chemical and electric) thruster was developed by at the Missouri University of Science and Technology to enable CubeSat propulsion missions. Two satellite buses, a 3U and 6U, are under development to demonstrate the multi-mode thruster's capabilities. Two key challenges related to these missions are the development of the feed system to support the thruster and management of the two bus programs' …

Propagation Of Uncertainty Through Coning, Sculling, And Scrolling Corrections For Inertial Navigation, James Daniel Alan Brouk

Masters Theses

"This thesis investigates the propagation of estimation errors through generalized coning, sculling, and scrolling algorithms used in modern day inertial navigation systems, in order to accurately quantify the uncertainty in the estimation of position, velocity, and attitude. The corrections for coning, sculling, and scrolling algorithms have an often unaccounted for effect on documented and empirically derived error statistics for measurements used to predict the uncertainty in a vehicle's position, velocity, and attitude estimates. Through the development of an error analysis for these generalized algorithms, mappings of the measurement and estimation errors through the correction termare generated. Using the developed mappings, …

Small Satellite Earth-To-Moon Direct Transfer Trajectories Using The Cr3bp, Garrett Levi Mcmillan

Masters Theses

"The CubeSat/small satellite field is one of the fastest growing means of space exploration, with applications continuing to expand for component development, communication, and scientific research. This thesis study focuses on establishing suitable small satellite Earth-to-Moon direct-transfer trajectories, providing a baseline understanding of their propulsive demands, determining currently available off-the-shelf propulsive technology capable of meeting these demands, as well as demonstrating the effectiveness of the Circular Restricted Three Body Problem (CR3BP) for preliminary mission design. Using the CR3BP and derived requirements from NASA's Cube Quest Challenge, five different trajectory scenarios were analyzed for their propulsive requirements. Results indicate that the …

Laser Machining Countersinks In Carbon Fiber Reinforced Polymer, Leon James Neely Hill

Masters Theses

“Laser machining countersinks with a frequency doubled Q-switched diode pumped Nd:YAG laser is demonstrated. Tests were conducted in 0.100" thick IM7 prepreg CFRP with [0,90]3S orientation. The HAZ is minimized to avoid stress concentrations in the epoxy matrix. A chamber and filtration system was designed and built to contain the byproducts produced in the machining process. The variables investigated are the number of repetitions in the offset path, the plunge rate, and the line energy. The research was performed over one baseline study, one parameter space exercise, two full factorial experiments, and one repeatability study. Assessment was done under an …

Variable Reluctance Virtual Torque Sensor For Automotive Applications, Vivek Iddum

Masters Theses

Torque sensing has been realized as one of the critical aspects in improving the dynamic vehicle performance in automotive systems. This thesis mainly presents the work on the development of a novel torque measurement method based on the estimation of nth-order flywheel angular acceleration from the variable reluctance flywheel speed sensor pulses. The number of firings in the engine determine the order of the harmonic to be used for torque estimation. The nth-order flywheel angular acceleration is computed using a micro-controller with built in timer counter and an associated signal conditioning circuit. The pulses obtained from the flywheel speed sensor …

Determination Of Chemical Notch, KChem On Aluminum And Steel When Subjected Under Slow Strain Rate Test In Corrosive Environment, Joshua Teo Lee Kuok

Masters Theses

When designing for any mechanical components or system, the question would arise as to how the material would react to the loads subjected on it? Would the component survive its service load? How would it react to environmental corrosion? To answer these questions, the technique used in this thesis paper is the Slow Strain Rate Test (SSRT) method. Aluminum and steel were chosen as the material to be tested in this paper. Al 7075-T651, and Al 6061-T651 was chosen due to its wide range of application, high strength to weight ratio and ease of machinability. It is highly used in …

Thermal Analysis And Control Of Small Satellites In Low Earth Orbit, Katelyn Elizabeth Boushon

Masters Theses

"Small satellites are becoming more popular in the space sector, primarily due to their lower cost and shorter development time. Much of the information available about satellite thermal analysis and control refers to larger spacecraft. Sorting through this information to find the practices specifically applicable for small satellites can be a daunting task, particularly for inexperienced engineers. This thesis study is intended to inform the reader about basic thermal control and analysis methods that relate specifically to small satellites in low Earth orbit. A case study involving a satellite designed by the Missouri University of Science and Technology Satellite Research …

Characterization Of Ionic Liquid Monopropellants For A Multi-Mode Propulsion System, Alex J. Mundahl

Masters Theses

"Multi-mode micropropulsion is a potential game-changing technology enabling rapidly composable small satellites with unprecedented mission flexibility. Maximum mission flexibility requires one shared propellant between the chemical and electric systems. A deep eutectic 1:2 molar ratio mixture of choline-nitrate and glycerol ([Cho][NO₃] - glycerol) is investigated as a fuel component in a binary mixture propellant for such a multi-mode micropropulsion. Specifically, binary mixtures of the novel ionic liquid fuel with hydroxyl-ammonium nitrate (HAN) and ammonium nitrate (AN) are considered and compared against the previously investigated propellant [Emim][EtSO₄]-HAN. Chemical rocket performance simulations predict this new propellant to have …

Effects Of Terrain-Based Altimetry On Navigation Performance, Kenneth Michael Kratzer

Masters Theses

"Navigation filters used during an entry, descent, and landing scenario often receive measurements related to the terrain over which the vehicle is traversing. Models of the terrain can be presented in varying degrees of fidelity, providing increasingly realistic and accurate models of the surface. While it is ideal to provide the filter with the most realistic model possible, the performance is limited by the strict nature of the real time scenario. Therefore, it is of interest to determine what level of fidelity is necessary to achieve an accurate filtering solution. Determining how best to incorporate terrain-related data into navigation solutions …

Quantifying On-Orbit Performance Of Cubesat Micropropulsion Systems By Observing Orbital Element Variations, Bradyn William Morton

Masters Theses

"The Advanced Propulsion Experiment mission in development by the Missouri University of Science and Technology's satellite research team (M-SAT) is a technology demonstration mission of a multi-mode propulsion system. The true test of any satellite propulsion system is the on-orbit performance. The purpose of this research is to develop methods for quantifying the on-orbit performance of the multi-mode propulsion system. This performance can be determined by observing the small variations in the orbital element parameters and using a differential corrector with the Gauss Variation of Parameter equations. Furthermore, this research could be used to determine and quantify a propulsion system's …

Developing Computational Models For Pulsed-Inductive Plasma Formation, Zachary Aaron Gill

Masters Theses

"Pulsed-inductive discharges are a common method of producing a plasma. They provide a mechanism for quickly and efficiently generating a large volume of plasma for rapid use and are seen in applications including propulsion, fusion power, and high-power lasers. However, some common designs see a delayed response time due to the plasma forming when the magnitude of the magnetic field in the device is at a minimum. New designs are difficult to evaluate due to the amount of time needed to construct a new geometry and the high monetary cost of changing the power generation circuit. To more quickly evaluate …

Development Of A Cfd Model Of The Catalytic Combustion Of A Microtube Multi-Mode Propulsion System, Andrew Paul Taylor

Masters Theses

"This thesis presents the process and results of the development of a computational fluid dynamics (CFD) model in ANSYS Fluent 18.1 on the catalytic decomposition of a novel liquid monopropellant in a microtube in order to gain deeper insights than what is available through the experimental data. The CFD model was created using the Euler- Euler Multiphase model in conjunction with the Heterogeneous Reaction submodel. Such a choice of modeling setting was backed up by theory and benchmark computations on multiphase and compressible flow, shown in Section 3 and Appendix A. It was found that the previously determined one-step reaction …

Model Predictive Power Management Of A Hybrid Electric Propulsion System For Aircraft, Tyler J. Wall

Masters Theses

This work presents the switched optimal power flow control for an aircraft with a hybrid electric propulsion system. The propulsion system is a switched system that operates in either of two modes: (i) battery discharging and electric motor propelling and (ii) battery charging and electric motor generating. The aircraft model and components that form the hybrid propulsion system are modeled as either an algebraic power source/sink or as a dynamic model with appropriate power and state interconnections. With the system model defined, a model predictive control power management strategy is set fourth which minimizes a performance index that includes altitude …

Experimental Study Of Global Luminescent Oil-Film (Glof) Skin-Friction Meter On Delta Wings, Patrick Nicholas Wewengkang

Masters Theses

This thesis describes how the Global Luminescent Oil-Film (GLOF) Skin-Friction Meter can be applied experimentally to extract skin-friction from a set of images. In this study, the effect of oil viscosity, experimental sample size, and step size were considered to see how they would affect the extracted skin-friction using the GLOF method. These results were then compared to published literature on skin-friction diagnostics of delta wings, based on observations of critical characteristics such as reattachment and separation lines. Delta wings of 50°, 55°, 60°, 65°, and 70° sweep angles were built and placed in the Small Wind Tunnel (SWT) at …

Development Of Empirical And Virtual Tools For The Study Of Bicycle Safety, Brent Kostich

Masters Theses

Bicycles have been used as a form of non-motorized transportation for several hundred years. Recently, their use in the transportation realm has been reinvigorated because of growing population densities and efforts to improve environmental sustainability. However, a large deterrent for public use of the bicycle is concern over its level of safety in the transportation environment. The goal of this thesis is to develop two complementary research tools that advance the study of bicycle safety factors.

First, an instrumented probe bicycle (IPB) is constructed from the ground up. The bicycle is outfitted with an array of sensors that are integrated …

Atmospheric Microbial Community Sampling System For Varying Altitude Collection, Kenneth David Domingue

Masters Theses

The study of airborne microbial communities in the vertical atmosphere is an area of research in which very little data has been collected and analyzed. Developing a vehicle to house biological sampling equipment that collects, and mitigates contamination is required by a team of biology researchers to perform sampling of atmospheric microbial communities. This study uses a sampler box that is attached to aerostatic vehicles: zero pressure balloons and tethered balloon/kite structures. Zero pressure balloons are used for sampling at altitudes above 150 m above sea level, and tethered balloon/kite structures are used for sampling at 30 m and 150 …

Satellite Sequencing Optimization And Observational Orbit Determination Using Genetic Algorithms, Andrew W. Verstraete

Masters Theses

The problem of mission design for a robotic servicing satellite in geosynchronous Earth orbit (GEO) was investigated. A representative set of potential client satellites was selected, and operational needs were randomly assigned based on the average number of GEO retirements, anomalies, and repositioning maneuvers that currently occur each year. An objective function was developed to represent the value of servicing mission sequences, including client fees, time penalties, and operational risk. A genetic algorithm was then used to find sequences of operations on the potential client set that maximized the objective function’s value. Scenarios were analyzed with the database of satellites …

Development And Implementation Of Star Tracker Based Attitude Determination, Casey Grant Smith

Masters Theses

"As interest in nanosatellites grows within the university community, the demand for inexpensive, space-grade hardware grows as well. Star trackers can be a luxury item for some spacecraft and therefore are often not considered due to their cost. Ideally, a star tracker could be built using inexpensive parts so long as the software is available. Unlike many other attitude determination instruments, star trackers are renowned for their high accuracy, yielding accurate and precise attitude estimates. However, development of this software can be overwhelming for the university settling, especially when multiple missions are on hand. If these instruments were readily available …

Liquid Pulsed Plasma Thruster Plasma Plume Investigation And Mr-Sat Cold Gas Propulsion System Performance Analysis, Jeremiah Daniel Hanna

Masters Theses

"The plasma plume produced by a liquid pulsed plasma thruster is investigated using a Langmuir triple probe and a nude Faraday probe. The Langmuir triple probe failed to produce results which are suspected caused by the presence of ionic liquid in the plume resulting in shorting of the probe. The nude Faraday probe is able to record the ion current density which revealed a high level of inconsistency in the plasma plume. Ion current density recorded by the nude Faraday probe had a relative standard deviation of upwards of 100% of the mean value. Controlling the amount of propellant used …

Entropy-Based Performance Analysis Of Jet Engines; Methodology And Application To A Generic Single-Spool Turbojet, Mohammad Abbas

Masters Theses

"Recently developed methodology that provides the direct assessment of traditional thrust-based performance of aerospace vehicles in terms of entropy generation (i.e., exergy destruction) is modified for stand-alone jet engines. This methodology is applied to a specific single-spool turbojet engine configuration. A generic compressor performance map along with modeled engine component performance characterizations are utilized in order to provide comprehensive traditional engine performance results (engine thrust, mass capture, and RPM), for on and off-design engine operation. Details of exergy losses in engine components, across the entire engine, and in the engine wake are provided and the engine performance losses associated with …

Wrinkling Of Functionally Graded Sandwich Structures Subject To Biaxial And In-Plane Shear Loads, Harold Costa

Masters Theses

"Benefits of a functionally graded core increasing wrinkling stability of sandwich panels have been demonstrated in a recent paper [1] where a several-fold increase in the wrinkling stress was observed, without a significant weight penalty, using a stiffer core adjacent to the facings. In the present paper wrinkling is analyzed in case where the facings are subject to biaxial compression and/or in-plane shear loading and the core is arbitrary graded through-the-thickness. Two issues addressed are the effect of biaxial or in-plane shear loads on wrinkling stability of panels with both graded and ungraded core and the verification that functional grading …

A Genetic Algorithm Incorporating Design Choice For The Preliminary Design Of Unmanned Aerial Vehicles, Kenneth Michael Mull

Masters Theses

Unmanned Aerial Vehicles (UAVs) are currently at the forefront of aerospace technologies. The design of these aircraft is complex and often performance characteristics are coupled to multiple design attributes. At the early design phase both discrete and continuous design choices are present limiting the feasibility of traditional derivative based optimization techniques. In place of these methods, the design space can be explored using a genetic algorithm that mimics the process of natural selection, providing a capable and reliable base airframe constructed from the required performance metrics. By incorporating a genetic multidisciplinary optimization algorithm early in the conceptual design phase, aircraft …

Modeling, Optimizing And Testing Thermoelectric Generators For Liquid-To-Liquid Low Grade Waste Heat Recovery, Ali Eyddan Hamil

Masters Theses

The use of thermoelectric generators (TEGs) for producing electricity from low grade waste heat is thought to be a great solution in the future to reduce the power generation cost because of their advantages of reliability and environmental friendliness. Therefore, the current project aims to study thermoelectric generators for low grade waste heat recovery. In this work, a single unit cell of liquid to liquid thermoelectric generator attached with heat exchangers (heat sinks) is modeled using an internal flow. Its optimum design is obtained based on heat sink optimization and the optimal design method. An analytical model of four unit …

Analytical Study Of Miniature Thermoelectric Device, Mohammed Dhannoon

Masters Theses

Miniature thermoelectric devices (TE) have been regarded as hopeful devices to attain efficient cooling in microprocessors and other small-scale devices. To recognize the performances of miniature thermoelectric coolers, a thermoelectric cooling module is theoretically analyzed. Particular attention is paid to the impact of the thermoelectric element length effect and the substrate material type influence on the cooling performance. The electrical contact resistance and thermal contact are taken into account.

Furthermore, miniature thermoelectric is compared with large thermoelectric, and effective material properties of miniature thermoelectric are studied. The obtained results also demonstrate power density (cooling/heating power per unit area of the …

Experimental Characterization And Simulation Of Carbon Nanotube Strain Sensing Films, Nagendra Krishna Chaitanya Tummalapalli

Masters Theses

Carbon Nanotubes (CNTs) have excellent mechanical, electrical and electromechanical properties. These properties led to a lot of novel applications. Due to change in electrical properties under mechanical loading, these composites have potential applications in strain sensors, when these are fabricated as films. CNT-based films are commonly fabricated using different physical and chemical techniques based on the property requirements governing those applications. In this work, CNT films were prepared using wet chemical based methods and chemical vapor deposition techniques.

Plasma chemical vapor deposition using microwave power is used in the first method to deposit films on silicon substrates, using Nickel film …

Analytical Modeling And Numerical Simulation Of A Thermoelectric Generator Including Contact Resistances, Shripad Dhoopagunta

Masters Theses

With increasing demand for energy harvesting systems, research has been conducted in different areas in which Thermoelectric Generators (TEG) find their way into the top of many available resources. Out of many energy harvesting systems available, TEGs are comparatively easier to study, to manufacture and also to comprehend while producing enough energy for applications they find use in. They are solid state devices, meaning; they do not have any moving parts and hence makes them durable. Most of the energy that goes out of the automobile as exhaust is reused to power the TEGs. In most of the works that’s …

Optimization Methodology For Cvt Ratio Scheduling With Consideration Of Both Engine And Cvt Efficiency, Steven Beuerle

Masters Theses

A transmission ratio schedule is developed to optimize the fuel consumption for an automotive continuously variable transmission (CVT) connected to an internal combustion engine (ICE). Although the optimal operating line (OOL) generated from an engine brake specific fuel consumption (BSFC) map can be used to generate a CVT ratio schedule that yields maximum engine efficiency, it was found that OOL-based CVT ratio scheduling does not necessarily offer the best fuel economy because optimal CVT efficiency does not always correspond to OOL tracking. To develop a CVT ratio schedule that can offer the best fuel economy, a novel ratio-scheduling methodology is …

Development Of An Analytical Model For Beams With Two Dimples In Opposing Directions, Mofareh H. Ghazwani

Masters Theses

Structures such as beams and steel plates can produce potentially high levels of unwanted vibrations and noises in the environment. A method of improving the vibration and acoustic characteristics of beams based on introducing dimples on its surfaces will be presented in this study. This method focuses on creating two dimples in the same and opposite direction on beam’s surface where the effect of dimples on the change in beam’s natural frequencies is the problems of interest.

A boundary value model (BVM) is developed for a beam with two dimples and subjected to various boundary conditions using Hamilton’s Variational Principle. …

Optimal Design Of Automotive Exhaust Thermoelectric Generator (Aeteg), Hassan Fagehi

Masters Theses

A consumption of energy continues to increase at an exponential rate, especially in terms of automotive spark ignitions vehicles. About 40% of the applied fuel into a vehicle is lost as waste exhaust to the environment. The desire for improved fuel efficiency by recovering the exhaust waste heat in automobiles has become an important subject. The thermoelectric generator (TEG) has the potential to convert exhaust waste heat into electricity as long as it is improving fuel economy. The remarkable amount of research being conducted on TEGs indicates that this technology will have a bright future in terms of power generation. …