Aerospace Engineering Commons^™

What Types Of Uncertainty Emerge In Instructional Aviation Incidents?, Abigail Henson

Mechanical Engineering Undergraduate Honors Theses

This study utilized narrative reports from the National Aeronautics and Space Administration (NASA) Aviation Safety Reporting System (ASRS) database to examine the types of uncertainty present in near-miss instructional aviation incidents occurring within the United States between 2015 and 2025. The final dataset consisted of 86 reports, with each report containing a set of narrative accounts from both the student pilot and the flight instructor operating under Part 91 regulations. Each instructional event was classified using a combined framework incorporating uncertainty categorizations and the Human Factors Analysis and Classification System (HFACS). Results indicate that epistemological uncertainty was the most common …

Cascaded Pid Control Of A Passive Bio-Inspired Rotating Empennage Aircraft, Zachary T. Jenkins

All Graduate Theses and Dissertations, Fall 2023 to Present

This thesis presents an autopilot for a Bio-Inspired Rotating Empennage (BIRE) aircraft. Most airplanes control yaw using a vertical stabilizer and a moving rudder, a design that has stayed essentially unchanged for nearly a century but adds weight, drag, and surface area to the aircraft. The BIRE removes the vertical tail entirely and instead allows the horizontal tail to rotate about the body x-axis of the airplane; tilting the horizontal tail produces a yaw force, doing the job of a rudder. This thesis first develops a controller for the BIRE where the empennage angle is commanded directly, then extends …

Flight System Development For A Bio-Inspired Rotating Empennage Experimental Unmanned Aerial Vehicle, Ashton Gilbert

All Graduate Theses and Dissertations, Fall 2023 to Present

Unmanned aerial systems, commonly known as drones, are increasingly used for research, environmental monitoring, and testing new aircraft concepts. Many commercially available drone flight controllers work well for standard aircraft designs, but they can be difficult to adapt for experimental vehicles that use unconventional control methods or require detailed monitoring during testing. This creates challenges for researchers who need flexible and reliable tools to safely evaluate new flight technologies. This work presents the development of a custom drone flight control system designed specifically for experimental research. The system integrates custom electronics and software that allow researchers to easily modify control …

A Data-Driven Koopman Framework For Station-Keeping On Near Rectilinear Halo Orbit, Anusha Sharma Malladi

Theses and Dissertations

Cislunar missions have gained significant attention in recent decades, motivating the need for efficient modeling and reliable control. In this work a Koopman operator based framework is developed for approximating the error dynamics around a reference Near Rectilinear Halo Orbit (NRHO) in the Earth-Moon Circular Restricted Three-Body Problem (CR3BP). A decoder free neural network is used to learn a lifted linear representation of the nonlinear CR3BP dynamics and a residual based approach is used to identify the corresponding control input matrix. The model is then implemented in a receding-horizon target point controller and compared with uncontrolled propagation and a State …

Developing Imitation Learning Policies By Exploring Diffusion Framework For Quadcopters, Likith Swamireddy

Theses and Dissertations

Imitation learning offers a promising approach in developing near-optimal onboard policies for nonlinear systems, by learning from computationally expensive trajectory planners during offline training. Existing State-of-the-art methods commonly learn deterministic mappings from observations to actions by training fast neural networks to mimic the expert demonstrations, which can limit their ability to capture the action distribution, when the policy is trained on multiple possible expert commands to reach the same target, and this may lead to unsafe scenarios in the obstacle environments. To address these challenges, this study explores Diffusion Models (DMs) as a feedback controller for quadcopters that learns the …

Developing Field And Spaceflight Microscopy, Nikki Johnston

Dissertations and Theses

Designing for spaceflight favors the reduction of unnecessary features and cost-cutting, whether thisbe computation, hardware, or procedure. Resources are spent toward fortification and mission success over convenience. Such design goals paired with the relatively smaller budgets of academia lead us to do as much as we can in-house and use open-source as much as we can without compromising mission success. We also believe that thoroughly testing technology in extreme environments on earth is necessary for the success of a flight instrument. We focus on microscopy for life detection. I have spent my time here learning methods of hand-building microscopes to …

Advancing The Oresat Adcs: Design & Implementation Of An Open-Source Reaction Wheel System, Chris Kane-Pardy

Dissertations and Theses

Reaction wheels provide the primary means of precision attitude control for many CubeSat attitude determination and control systems by exchanging angular momentum with the spacecraft body. As the Portland State Aerospace Society's OreSat spacecraft transitioned from a 2U to a 3U configuration, the increased spacecraft inertia reduced the attitude control authority available from the legacy reaction wheel system. This thesis addresses that challenge through the redesign of the reaction wheel system and the development of a deterministic embedded controller and experimental framework for evaluating brushless motor commutation strategies under identical operating conditions.

The redesigned system combines an analytically sized flywheel, …

Accelerating Rans Cfd Convergence For Bluff Body Flows Using Surface-Vorticity Panel Solver Initialization, Trisha Babu

All Graduate Reports and Creative Projects, Fall 2023 to Present

Reynolds-Averaged Navier--Stokes (RANS) simulations are widely used for predicting aerodynamic performance in engineering applications but often require substantial computational time to achieve convergence, particularly for bluff-body flows characterized by large-scale separation and wake formation. Improving the initialization of CFD simulations offers a practical approach for reducing computational cost without modifying the underlying numerical algorithms. This study investigates the use of a surface-vorticity panel solver (FlightStream) to generate physically informed velocity fields for initializing steady RANS simulations in STAR-CCM+.

Two canonical bluff-body geometries are considered: a sphere at a Reynolds number of 5 X 10⁵ and an isolated cube at …

Theory, Implementation, And Practical Applications Of A Modern Parabolized Navier-Stokes Code, Logan B. Freeman

All Graduate Theses and Dissertations, Fall 2023 to Present

The Parabolized Navier-Stokes (PNS) method is a specialized computational approach for solving the equations that govern fluid flowing faster than the speed of sound, known as supersonic flow. By leveraging unique physical properties of supersonic environments—specifically that information cannot travel upstream—this method allows for significantly more efficient calculations than traditional approaches. Supersonic flows are important for many military and civilian applications including hypersonic weapons, high-speed passenger aircraft, and reentry. This thesis provides a comprehensive review of the two-dimensional PNS formulation, detailing the mathematical derivation and its practical implementation for solving flow problems. Through performance analysis and error assessment, this research …

Simulation Of Hypersonic Conditions In A Lab-Scale Environment Using A Hybrid Rocket With Nitrogen Cooling, Joshua R. Sorenson

All Graduate Theses and Dissertations, Fall 2023 to Present

Developing hypersonic vehicles requires testing under extreme heat, airflow, and pressure. Traditional facilities like shock tunnels and arc-heated wind tunnels are costly and slow to set up. This thesis proposes a simpler, low-cost method using a small-scale hybrid rocket motor as a gas generator. The rocket’s hot exhaust is directed onto the front edge of a scaled-down model that represents the nose of a hypersonic vehicle. This creates a realistic flow that matches both the intense heat energy and the pushing force experienced in high-altitude hypersonic flight. The setup allows easy measurement of motor performance, surface pressures, leading-edge temperatures, and …

A Cfd-Dem Framework For Characterizing Nanoparticle Adhesion Effects On Creeping-Flow Permeability In Composite Manufacturing, Gavin Stoker

All Graduate Theses and Dissertations, Fall 2023 to Present

Modern aircraft, spacecraft, and high-performance vehicles are increasingly built from composite materials, engineered combinations of plastics and fibers that are lighter and stronger than traditional metals. Researchers are now pushing these materials further by mixing in microscopic particles thousands of times smaller than a human hair, called nanoparticles, to make them even tougher and more resistant to damage. The challenge is getting those nanoparticles distributed evenly. During manufacturing, liquid plastic resin is pumped through a network of tightly packed fibers, carrying the nanoparticles along with it. But nanoparticles tend to clump together and stick to surfaces as they travel, clogging …

Smart Process Planning For Automated Fiber Placement, Matthew J. Godbold

All Dissertations

Automated Fiber Placement (AFP) is a preeminent manufacturing technology for producing high-performance composite structures, offering precise material placement, reduced waste, and the potential for highly optimized lightweight designs. While AFP has been widely adopted in aerospace applications, its broader use across industries such as automotive, wind energy, maritime, and sporting goods remains limited. A key barrier to wider adoption is the traditional separation of design, manufacturing, and inspection processes, which drives up cost and results in inefficiencies, sub-optimal designs, and limited feedback between lifecycle stages. In current practice, manufacturing is treated as an isolated process, disconnected from early-stage design decisions …

Machine Learning For Predictive Energy And Emissions Modeling Of Vehicles And Power Grids In The United States, S M Tanvir Faysal Alam Chowdhoury

Dissertations

The environmental benefits of electric vehicle (EV) adoption depend on more than replacing internal combustion engine vehicles with electric powertrains. EV adoption reshapes electricity demand, interacts with regional generation mixes, and influences travel behavior and congestion, creating a coupled transportation-energy system in which vehicle and power-plant emissions must be evaluated together. This dissertation develops machine-learning frameworks for predicting energy consumption and emissions from vehicles and power grids under rising EV adoption. The first component forecasts grid emissions from EV charging. Using simulation data from NREL's Cambium database, a Prophet-based time-series framework predicts carbon dioxide, nitrous oxide, and methane emission rates …

Residual Stress Informed Reconstruction And Failure Analysis Of Manufacturing Induced Composite Meso-Structure, Mohammad Nazmus Saquib

Mechanical & Aerospace Engineering Theses & Dissertations

A physics informed, AI-augmented framework is developed to enable digital twins of molded composite materials by linking manufacturing induced residual stresses to a local meso-structure. By reconstructing and explicitly modeling these architectures, the framework reveals how processing driven meso-structural variability governs stiffness, damage evolution, and failure. The work focuses on two technologically important systems: prepreg platelet molded composites (PPMC), characterized by inherently stochastic platelet architectures, and 2/2 twill glass fiber/PA6 organosheets, whose periodic but locally variable weave geometry influences mechanical response. For PPMC, the Residual Stress Informed Microstructure Reconstruction (ResIMiR) framework is introduced, combining thermoelastic strain fields with deep learning …

Toward Risk-Informed Design Of Supercooling Heat Exchangers: Statistical Inference And Experimental Investigation Of Heterogeneous Ice Nucleation, Daniel B. Gardner

All Graduate Theses and Dissertations, Fall 2023 to Present

Ice-based cooling storage systems can reduce electricity costs and grid strain by making ice during off-peak hours and using it for air conditioning during the day. One promising design works by chilling water below its freezing point as it flows through a heat exchanger, then allowing it to freeze in a separate storage tank. The challenge is that the chilled water can freeze prematurely inside the heat exchanger itself, blocking the flow and shutting the system down. Preventing this unwanted freezing requires understanding how and where ice begins to form on surfaces, a process called nucleation.

This dissertation investigates ice …

Characterization, Transport Modeling, And Image Analysis Of Rover-Terrain Interaction For Lunar Regolith In-Situ Resource Utilization, Luke A. Manolescu

All Theses

NASA has declared a return to the lunar surface and the need and demand for sophisticated In-situ Resource Utilization (ISRU) is the highest in history. ISRU will require regolith excavation, transport, and processing in order to harvest the valuable resources available, support surface operations, and keep astronauts alive. Characterizing the lunar regolith is essential to understanding the mechanical and physical behavior of the material that will be used to construct berms and structurally support astronaut habitats and landers. Any construction on Earth requires an in-depth geotechnical site assessment prior to any construction to rule out any potential site issues that …

Effect Of Solid Particle Size And Density On Incipient Motion In A Turbulent Boundary Layer, Robert Bryan

Doctoral Dissertations and Master's Theses

Wind-blown sand and other instances of solid particles mobilized and suspended in gaseous turbulent boundary layers (TBLs) are seen in a wide variety of engineering contexts. An experimental framework was developed to study the incipient particle motion driven by external forcing within a turbulent boundary layer, which is provided by an airfoil section oscillating in the free-steam flow, resulting in a periodic disturbance in the near-wall region through production of synthetic large-scale structures at a fixed frequency. The incoming unsteady carrier-phase eddies were measured with a hot-film sensor upstream of a particle bed, and the particle motion was captured by …

Assessing Computer Vision Based Conflict Detection In Uas Traffic Monitoring Under Secure Communication Constraints, Fadjimata Issoufou Anaroua

Doctoral Dissertations and Master's Theses

The rapid growth of Unmanned Aircraft Systems (UAS) and Advanced Air Mobility (AAM) is creating a new low-altitude airspace ecosystem where drones, air taxis, service suppliers, communication networks, sensors, and ground-based monitoring systems must work together safely. Within this ecosystem, UAS Traffic Management (UTM) is expected to provide a digital framework for coordinating operations beyond traditional air traffic control. However, reliable integration also requires resilient monitoring methods that can detect non-cooperative aircraft, protect communication links, and maintain timely situational awareness under real-world constraints.

This dissertation examines how computer vision can support cooperative monitoring systems such as Remote ID and ADS-B …

System Integration And Validation Of The Cal Poly Spacecraft Attitude Dynamics Simulator Mk. Iv, Bricen S. Rigby

Master's Theses

The Cal Poly Spacecraft Attitude Dynamics Simulator (SADS) is an ongoing project that seeks to enable the simulation and validation of sensors, actuators, and control logic related to spacecraft attitude control. The SADS platform rests atop a spher- ical air-bearing device which allows for nearly frictionless rotation in all three axes. The orientation of the platform is controlled by four reaction wheels arranged in a pyramidal configuration. Over the past few years, there have been significant updates to the reaction wheel subsystem, as well as requests for a more capable central com- puter. Therefore, a new system architecture for the …

Prediction Of Satellite Temperature During An Orbit Of A Cubesat, Michael Reynolds

Honors Theses

This thesis develops a thermal-simulation strategy for predicting CubeSat component temperatures, applied to Jag-Sat-1, a CubeSat developed at the University of South Alabama and deployed from the International Space Station in 2022. The orbit was reconstructed from two-line element (TLE) data using simplified general perturbations (SGP4) propagation, and spacecraft attitude was recovered from onboard gyroscope measurements. Sunlight, penumbra, and umbra intervals were computed geometrically, and the external radiative environment — direct solar, Earth infrared, and albedo heat fluxes — was modeled using orientation-dependent view factors. These time-varying fluxes drove a transient finite-element thermal simulation of the full satellite geometry in …

Direct Ink Writing Of Functional Fiber/Granular Composites, Zhuoyuan Yang

Doctoral Dissertations and Master's Theses

Direct ink writing provides a versatile manufacturing route for fabricating functional fiber and granular composites with controlled architecture, tunable interfaces, and customized material distributions. Fiber reinforced composites offer high stiffness, strength, fatigue resistance, and functional anisotropy, while granular composites provide scalable access to particle based structures with high material efficiency and broad resource compatibility. However, the additive manufacturing of these composite systems remains challenging. For fiber based composites, precise control of fiber placement, matrix impregnation, interfacial bonding, and freestanding deposition is difficult to achieve during printing. For granular composites, stable particle flow, controllable packing, binder infiltration, and shape retention are …

Cohesive Zone Modelling Of Fiber–Matrix Interface In Composite Materials, Arjun Myadam

Doctoral Dissertations and Master's Theses

Carbon Fiber reinforced polymers (CFRPs) are widely used in aerospace, automotive, and structural applications due to their high specific strength, stiffness, and design flexibility. Their mechanical performance is critically governed by the fiber–matrix interface which controls stress transfer and directly influences damage initiation, crack propagation, and fracture behaviour. The interface properties are quantified through the Interfacial Shear Strength (IFSS) and fracture energy, both serving as key indicators of composite integrity. Effective interfacial bonding is therefore essential to the composite’s strength. Nanoscale fiber surface modifications provide a promising approach to enhance interfacial bonding and can also impart multifunctionality. These multifunctionalities can …

Compact Cislunar Orbital Representation For Efficient Tracking In Cislunar Space, Mauro Palomo

Doctoral Dissertations and Master's Theses

Expanding lunar missions require efficient, interoperable orbital tracking where existing methods fail to scale. Two-Line Elements (TLEs) lack applicability beyond geocentric regimes, while high-accuracy Orbit Ephemeris Messages (OEMs) require excessive data volumes and bandwidth to communicate. To support increased lunar traffic, this paper proposes the Compact Cislunar Orbital Representation (CCOR), providing a novel framework that strikes a balance between TLE level efficiency and OEM-level fidelity, ensuring multi-actor communication for missions in the cislunar region. By evaluating the framework across six diverse cislunar trajectories, this study demonstrates the CCOR’s robustness and ability to compress thousands of OEM state vectors into a …

Experimental-Motion-Driven Cfd Investigation Of Slosh Dynamics In Propellant Tanks Of Spacecraft And Launch Vehicles, Priyanshu Savaliya

Doctoral Dissertations and Master's Theses

Liquid sloshing in partially filled propellant tanks can generate transient forces and moments that affect spacecraft and launch vehicle stability, guidance, and control. This research develops a one-way experimental-to-Computational Fluid Dynamics (CFD) integration framework to investigate free-surface slosh behavior under realistic excitation conditions.

The overarching goal of this thesis is to develop and evaluate a one-way experimental-motion-driven computational framework for predicting liquid slosh response in a partially filled cylindrical tank. Rather than relying on idealized sinusoidal inputs, this work uses experimentally measured actuator-feedback motion as the prescribed excitation for high-fidelity CFD. The central objective is to establish the experimental and …

Noise-Optimized Routes For Air Taxi, Waleed Raza

Doctoral Dissertations and Master's Theses

Community noise is a primary barrier to the public acceptance and deployment of Advanced Air Mobility (AAM) and Urban Air Mobility (UAM) air taxi operations. This dissertation develops a coupled siting, routing, and noise optimization framework that links vertiport placement to its downstream acoustic consequences, demonstrated through a Daytona Beach case study. Candidate vertiports are screened and selected using accessibility, safety, demand, and feasibility criteria, and the selected sites form a directed network of 20 routes. Each trajectory is evaluated with a physics-based acoustic pipeline reporting Lmax, SEL, and EPNL at school, hospital, and residential receptors, showing that received exposure …

Optimal Integrated Cfd-Gnc Model For Drag-Based Reentry Dynamics, Sebastian Lopez

Doctoral Dissertations and Master's Theses

This research focuses on optimizing the control of a drag-maneuvering, Starship-class re-entry vehicle by closely integrating high-fidelity aerodynamic data derived from Computational Fluid Dynamics (CFD) simulations, specifically using StarCCM+. The aerodynamic models, tailored to the unique geometry of a drag-maneuvering body, are seamlessly incorporated into a guidance, navigation, and control (GNC) framework. This integration enables closed-loop CFD simulations with real-time control feedback, allowing for direct analysis and optimization of vehicle stability, trajectory, and control demands throughout the re-entry process.

Building upon the work of Gaglio and Bevilacqua, this advanced CFD-GNC model introduces high-order aerodynamic effects, such as aerodynamic moments and …

Numerical Investigation Of Shock-Induced Deformation Of Bubble-Laden Droplets, Juan Roldan

Doctoral Dissertations and Master's Theses

Rain impact can be a source of surface erosion on hypersonic vehicles, and the severity of each impact depends on droplet velocity, mass, and final shape, all of which are set by how the droplet breaks up under shock loading. Real droplets are expected to carry entrained non-condensable gas (NCG) nuclei from their formation. This dissertation investigates whether the purely mechanical, pressure-driven response of these nuclei, independent of vaporization, is large enough to measurably alter the internal pressure field and early deformation of a shock-loaded droplet.

The droplet and surrounding gas are modeled with a compressible, diffuse-interface, axisymmetric Eulerian framework …

Advancing Sensing And Structural Health Monitoring Of Non-Conventional Space Structures, Scott Bender

Doctoral Dissertations and Master's Theses

Future lunar and deep-space missions will require new structural concepts that reduce mass while maintaining reliability. Two technologies that have received significant attention are inflatable habitats and additively manufactured structures; however, challenges remain in their characterization, validation, and long-term monitoring. This dissertation investigates methods to improve the testing and sensing of these non-conventional aerospace structures through the use of advanced photogrammetry and embedded distributed fiber-optic sensors. A color-filtering digital image correlation technique was developed to isolate orthogonal strain directions in woven inflatable structures, providing improved characterization of biaxially loaded softgoods. In addition, methods were developed to embed distributed fiber-optic sensors …

A Systems Analysis Of Autonomous Uav Swarm Spraying For Precision Agriculture, Ryker Davis

Graduate Theses and Dissertations

The application of Unmanned Aerial Vehicles (UAVs) in civilian sectors, particularly for precision agriculture and targeted aerial spraying, has rapidly evolved from passive monitoring to advanced, autonomous, multi-agent coordination. While deploying UAV swarms offers a promising solution to the payload and battery endurance limitations of single drone operations, realizing field-scale coverage introduces significant logistical and safety challenges. To evaluate the trajectory and viability of swarms, this study synthesizes bibliometric trends, operational simulation, and safety reporting analysis. First, because physical testing of complex swarms poses financial and safety risks, we developed an agent-based and discrete event simulation to evaluate autonomous spraying …

Mars Rover Wheels And Drive, Presley S. Sacavitch, Ryan W. Trevena, Dylan A. Mack, Daniel Hudak

Mechanical Engineering

Cal Poly’s Poly1Rover team, advised by Professor Rich Murray, aims to deploy four student-designed mini-Mars rovers, each equipped with a sample-tube retrieval claw, before 2030. However, the wheels of Poly1Rover’s current 6th generation rover are not ready for deployment to Mars, as they do not utilize space-grade materials, are not optimized for manufacturability, and lack sufficient spoke compliance to absorb landing and high-impact loads. This project will be developed by a team of Mechanical Engineering students at California Polytechnic State University, San Luis Obispo (Cal Poly): Daniel Hudak, Dylan Mack, Presley Sacavitch, and Ryan Trevena. Next Intent is providing funding …