Aerospace Engineering Commons^™

Deep Reinforcement Learning For Leo Satellite Grouping, James E. Minteer

Theses and Dissertations

This research investigates jamming evasion using DRL to provide an autonomous solution that repositions a geostationary satellite experiencing directed, terrestrial based jamming. Second, this thesis applies DRL to an area of research for LEO satellite constellations, user grouping, using a portion of an Air Force Research Lab reinforcement learning framework. As LEO satellites orbit the earth, they must constantly re-evaluate not only which users they are able to connect to, but on which of its multiple beams. This model succeeds in finding a balance between maximizing signal strength and minimizing overhead from switching user assignments, all while requiring fewer costly …

An Analytical Approach In Solving A Two-On-One Pursuit Evasion Differential Game With Fast Evader And No-Point Capture, Nathan T. Morrow

Theses and Dissertations

This paper is concerned with a co-planar pursuit-evasion scenario where two Pursuers (P) are after an Evader (E). The players are holonomic/can turn on a dime and their speeds, V_P and V_E, are constant, but the evader is faster than the pursuers, that is, the speed ratio parameter μ =  V_E/V_P > 1. The Pursuers are endowed with a circular capture disc whose radius l > 0. A differential game (DG) with three states and one parameter is addressed through geometric and analytical methods where a partial solution is outlined and visualized. The game is split …

Choosing Robust Leadership: Encompassing The Best-Of-N Model And Swarm Intelligence Optimization For Heterogeneous Multiple Autonomous Unmanned Aerial Vehicle Systems, Kudamuhandiramlage Harith Kolitha Warnakulasooriya

Shelby Hall Graduate Research Forum Presentations

Presentation slides for a presentation given at the 1st annual Shelby Hall Graduate Research Forum at the University of South Alabama.

Thermal Stability Analysis Of Aqueous Ionic Amines For Sustainable Co2 Capture, Li Hua Zang, Keegan Everitt, Kevin West, Brooks D. Rabideau, Breanna Dobyns, James Davis

Shelby Hall Graduate Research Forum Posters

In closed air cabin atmospheres such as those of spacecraft, CO₂ accumulation jeopardizes crew respiratory function and may gradually affect sensitive equipment, making effective air revitalization critical. Traditional CO₂ capture methods like monoethanolamine (MEA) efficiently capture CO₂ but suffer from high volatility, leading to solvent loss and unpleasant odor, as well as corrosion and degradation, requiring frequent replacement. These flaws demand eco-friendly, durable alternatives. This study addresses these limitations by exploring a series of aqueous ionic amines (AIAs), salts similar to MEA in CO₂ capture efficiency but with improved thermal stability—crucial for preventing degradation under high regeneration temperatures and prolonged …

Extension Of The Circular Restricted N-Body Problem (Crnbp) To Varying Multi-Body Gravitational Systems, Annika J. Gilliam

Theses and Dissertations

Multi-body dynamical models are a valuable tool used to examine certain aspects of spacecraft orbital mechanics by applying assumptions to restrict the problem. The Circular Restricted Three-Body Problem (CR3BP), one of these dynamical models, has been examined extensively in the last few decades; however, this model is not sufficient in the case of more than two massive celestial bodies gravitationally affecting a spacecraft. A novel model called the Circular Restricted N-Body Problem (CRNBP) is studied in this research as an alternative to the traditional CR3BP where necessary. A variety of systems are examined in this thesis, including the Jovian, Saturnian, …

Creating And Analyzing Space Vehicle Seit/Pm Factors, Jordan A. Bosco

Theses and Dissertations

The Department of Defense relies on accurate cost estimation to inform budget decisions. Beyond being a critical component of the Defense Acquisition System, cost estimation is a legal requirement in the budgeting process. Cost analysts, therefore, have both a fiduciary and statutory responsibility to produce realistic estimates. Among the many elements of a space system cost estimate is Space Vehicle Systems Engineering, Integration & Test, and Program Management (SEIT/PM). While existing factors aid in estimating SEIT/PM, Space Systems Command is interested in research in alternatives to the current methods and crosschecks for those methods. This study develops a set of …

A Multi-Objective Reinforcement Learning Framework For Title Autonomous On-Orbit Inspections, Austin C. Reynolds

Theses and Dissertations

The rapidly evolving landscape of space operations necessitates dynamic and autonomous systems to address complex challenges such as Resident Space Object (RSO) inspections. This research explores the application of a Multi-Objective Reinforcement Learning (MORL) framework to rendezvous and proximity operations (RPO), enabling agents to balance conflicting objectives like time efficiency, fuel conservation, and information gain. Unlike traditional reinforcement learning, MORL allows dynamic reweighting of objectives without retraining, offering adaptability and efficiency in multi-objective environments. The study demonstrates MORL's capabilities through custom 2D and 3D simulations of Hill-Clohessy-Wiltshire (HCW) environments and comparing its performance to traditional RL in RPO scenarios. Tasks …

Commercial Satellite Payload Trends, Alexander B. Krawietz

Theses and Dissertations

This thesis examines the evolving trends in commercial satellite payloads with an emphasis on mass, operating power, and project duration overall and across different payload types, serving as a benchmark for Department of Defense (DoD) leaders to compare against private industry advancements. Utilizing a comprehensive dataset of open-source commercial satellite data, this study identifies significant trends that could influence cost estimation, schedule estimation, and satellite design. The analysis not only highlights the technological progression over several decades but also provides a comparative insight into how the United States and China are positioned in their race for space dominance. Beyond detecting …

Utility Of Self-Sensing Damage Technology Through A2/Ad Drone Combat Simulation, Sidhanth Venkatasubramaniam

Theses and Dissertations

Since the introduction of the first unmanned aerial vehicle (UAV), UAVs have consistently improved in capability and versatility. The ability to perform military operations without the risk of losing human life is crucial for the United States military. The trade-off for this versatility is cost, and several ongoing research efforts are being made to improve UAV mission success and the lifespan of UAVs. An area of research that falls under the categories mentioned is self-damage detection. The Air Force Research Laboratories (AFRL) are developing a capability to enable a UAV to assess airframe damage, enabling real-time determination of damage potentially …

Universal Model Based Systems Engineering Rendezvous And Proximity Operations Mission Planner, Thomas J. Kelly

Theses and Dissertations

This thesis addresses the fragmentation and inefficiencies in current Rendezvous and Proximity Operations (RPO) mission planning by developing an integrated Model-Based Systems Engineering (MBSE) framework. The research explores the design and implementation of RPO missions using System Modeling Language (SysML) and Matlab-based physics simulation to improve mission planning processes. Key objectives include the standardization of mission requirement characterization, the development of evaluation criteria for mission plans, and the implementation of iterative design methods to refine RPO strategies. The study leverages the Hill-Clohessy-Wiltshire (HCW) equations for initial mission planning, incorporating rigid-body attitude control with properties generated from the physical description, and …

Adiabatic And Overall Effectiveness Superposition Theory For Upstream Phantom Cooling On A Film Cooled Leading Edge, Nathaniel J. Stout

Theses and Dissertations

Film cooling experimentation aims to improve the cooling performance while minimizing the amount of coolant flow redirected from the compressor. The coolant flow that is used for film cooling reduces the maximum thrust any gas turbine engine can produce. Finding creative ways to improve cooling performance without increasing the amount of coolant used, like phantom cooling, is essential for the gas turbine industry to improve engine performance while increasing turbine components’ lifespan. Phantom cooling refers to any secondary cooling effect that propagates downstream from its original cooling application to cool subsequent turbine components. Phantom cooling is actively gaining more attention …

Thin-Filament Pyrometry In A Rotating Detonation Engine, Theodore B. Guetig

Theses and Dissertations

Rotating Detonation Engine (RDE) proves beneficial by creating a pressure rise across the combustor rather than a pressure drop seen in traditional aircraft combustors. Coupled with this high pressure is a high temperature in the detonation engine that is difficult to measure as it varies spatially and temporally. Thin-Filament Pyrometry (TFP) was performed on a 6-in RDE to measure these high temperatures. Temperature profiles were obtained over a variety of mass flows, equivalence ratios, and different axial locations within the RDE providing insight into the mixing process and where the heat release occurs. Successful determination of these temperature profiles within …

Solid State Transformer Controls For Mitigation Of E3a High-Altitude Electromagnetic Pulse Insults, Connor A. Lehman, Rush D. Robinett, Wayne Weaver, David G. Wilson

Michigan Tech Publications

This paper explores the use of a solid state transformer (SST) to mitigate the 𝐸3𝐴 component of a high-altitude electromagnetic pulse (HEMP) insult using external energy storage optimal control techniques. In lieu of conventional passive blocking devices or feedback-controlled energy storage devices, a novel implementation of Hamiltonian error tracking is utilized to develop a feedback control law for the variable converter ratio in an SST. The findings of the simulations performed in this paper suggest that additional energy storage is not necessary to protect an individual load from a HEMP insult. The simulations performed examine the response of a single-phase …

Stanag 4575 Cst M35, Will Scheirer, Lee Sublett, George Weiss, Tina Howell, Ben Hill, Jared Sanders

Space Dynamics Laboratory Publications

General Information

➢ Provides a standardized “direct data download” capability from any NADSI compliant ISR data acquisition recorder to a compliant ground station

➢ STANAG 4575 Ed.4 became a mandated DISR standard for US DoD organizations on 24 April 2018; STANAG 4575 Ed. 5 is currently under JCGISR silence procedure until 14 February

➢ Magnetic Disk, Solid State, Complete Units, or Removable Media Modules (RMMs); Non-proprietary Directory and File Structure

➢ Based On Commercial Gigabit Ethernet Standards TCP/IP and Fiber Channel

Ongoing Efforts

➢ Working NADSI Ed.5 implementation with various national and international industry partners and manufacturers

➢ Further NADSI …

Quality Evaluation For Colored Point Clouds Produced By Autonomous Vehicle Sensor Fusion Systems, Colin Schaefer, Zeid Kootbally, Vinh Nguyen

Michigan Tech Publications

Perception systems for autonomous vehicles (AVs) require various types of sensors, including light detection and ranging (LiDAR) and cameras, to ensure their robustness in driving scenarios and weather conditions. The data from these sensors are fused together to generate maps of the surrounding environment and provide information for the detection and tracking of objects. Hence, evaluation methods are necessary to compare existing and future sensor systems through quantifiable measurements given the wide range of sensor models and design choices. This paper presents an evaluation method to compare colored point clouds, a common fused data type, among two LiDAR-camera fusion systems …

Flight Crew And Aviation Sustainability, Eva Maleviti

Publications

Sustainable Development

The concept of sustainable development was defined in the World Commission on Environment and Development’s (WCED) 1987 Brundtland Report ‘’Our Common Future’’. The Brundtland Commission aimed to help world nations towards sustainable development. Then, sustainable development became an essential concept in the vocabulary of politicians, practitioners, and planners.

Metaheuristic Techniques To Optimize Trajectory Planning Of Uav Swarms: Enhancing Data Acquisition In Wireless Sensor Networks, Nada Ali Mohamed Ahmed Ahmed

Theses and Dissertations

Unmanned aerial vehicles (UAVs) have become increasingly integrated into various applications due to their cost-efficiency, rapid deployment, flexible maneuvers, and enhanced performance. This has led to the development of a new field called UAV-assisted Wireless Sensor Networks (U-WSNs), which focus on data routing, network performance optimization, and planning UAV trajectories between sensor nodes in wireless sensor networks. In this thesis, a new framework has been proposed to manage a swarm of UAVs cooperatively serving large-scale wireless sensor networks. The framework consists of three optimization problems: distributing sensor nodes among UAVs, finding optimal trajectories in the presence of obstacles, and performing …

The Future Of Aviation: Becoming An Evtol Pilot – Faa’S New Regulations Open Up Career Opportunities, Sarah Nilsson

Publications

As the aviation industry stands on the brink of a revolutionary change, aspiring pilots are increasingly drawn to the exciting prospect of flying electric Vertical Takeoff and Landing (eVTOL) aircraft. The allure of this cutting-edge technology has many asking: “How does one become an eVTOL pilot in the United States?” This question opens up a cascade of inquiries about the future of flight training, the certification process and the transition for existing pilots into this new realm of aviation like:

• What will the flight training curriculum look like for eVTOL aircraft?

• Who will be the pioneering Certified Flight …

Stabilizing A Bio-Inspired Rotating Empennage Fighter Aircraft In Multiple Trim Scenarios, Benjamin C. Moulton, Matthew W. Harris, Douglas F. Hunsaker

Mechanical and Aerospace Engineering Student Publications and Presentations

This paper considers the problem of stabilizing a bio-inspired fighter aircraft at its Air Combat Maneuver Condition in steady level and coordinated-turning flight. The aircraft equations of motion are linearized, and an infinite-horizon linear quadratic regulator design is conducted. The open-loop system is unstable in the short period and Dutch roll modes. This is mitigated in the closed-loop system, which is analyzed in the time and frequency domains. Included in the simulation dynamics are first-order actuator models, actuator deflection limits, and actuator rate limits. These are particularly important for this bio-inspired aircraft because control actuation requires rotation of the empennage, …

The Problem Of Reducing The Wave Resistance Of Blunt Bodies At Supersonic And Hypersonic Velocities, Oleksandr M. Shyiko, Olexii A. Оbukhov

Journal of Aviation Technology and Engineering

A new method for reducing the aerodynamic wave drag of blunt bodies in supersonic and hypersonic flows is considered. The method is based on the destruction of the detached head shock wave by placing a family of thin needle elements of a cone-shaped or cylindrical type on the blunt surface. This qualitatively changes the gas-dynamic flow pattern and leads to a new positive quantitative effect. The bow shock wave breaks up into a series of local interacting shock waves of lower intensity, which leads to a decrease in the wave drag of the streamlined body. Variants of hemispherical blunting of …

Circular Dichroism In Achiral Metasurfaces Induced By Spatially Selective Coupling With Molecules, Baojuan Han, Xiaodong Yang, Jie Gao

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Achiral metasurfaces with near-field optical chirality have attracted great attention in molecular sensing and chiral emission control. Here, the circular dichroism (CD) response of an achiral metasurface induced by spatially selective coupling with polymethyl methacrylate (PMMA) molecules is demonstrated. A designed achiral metasurface with a V-shaped resonator exhibits large optical chirality with a strongly dissymmetric distribution under circular polarization. By introducing a PMMA molecule layer on top of the metasurface, which covers the area with large optical chirality, CD in absorption of 0.38 and a dissymmetric factor of optical chirality gc of 0.16 are obtained. Furthermore, an analysis of the …

Optimization Of The Cross-Section Of Generic Flexible Bridges, Manal Kamal Zaki, Mina M. Helmy, Mark M. Tawadros

Journal of Engineering Research

This paper investigates the behavior of flexible bridges prone to aerodynamic instabilities due to wind. Optimal cross-sections that reduce aerodynamic forces are recommended. This is achieved by studying a variety of bridge sections with different widths of upper and lower sloping edges in addition to studying the upper and lower cramps of the deck. The wind velocities are also parameterized. Computations are developed based on the powerful computational fluid dynamics (CFD) method known as FLUENT and embedded in ANSYS software. For parametric study, a design of experiments (DOE) is performed based on the response surface methodology (RSM) combined with the …

Turbulent Structures In Coupled Wind-Wave Flows, Cerrina Mouchref

Dissertations and Theses

The interactions between wind and waves in offshore environments are complex and have yet to be fully understood. Analyzing these interactions is motivated by an increased interest in climate modeling and the deployment of offshore construction, such as offshore wind farms. In this study, experiments are performed in a wind tunnel using particle image velocimetry (PIV) to analyze wind-wave interactions over various wave and wind speeds. The addition of the wave, a moving boundary, leads to the use of Reynolds triple decomposition in order to separate the turbulent and wave-phase coherent fluctuations. A curvilinear coordinate system was used to analyze …

Evaluation Of Stability And Controllability Of The Multiple Trim Solutions For A Bio-Inspired Rotating Empennage Fighter Aircraft, Benjamin C. Moulton, Christian R. Bolander, Douglas F. Hunsaker

Mechanical and Aerospace Engineering Student Publications and Presentations

Aircraft with non-traditional actuators tend to have multiple or infinite trim solutions for a single flight condition. For a given flight condition the bio-inspired rotating empennage fighter aircraft has multiple distinct trim solutions with varying tail rotation angles. In the present work these trim solutions are evaluated from various perspectives including: minimum drag, dynamic stability, controllability, and degree of controllability. The results of these analyses can be used to further constrain a trim solver routine such that a trim solution is found meeting a desired criterion. The purpose of the present paper is to evaluate the multiple trim solutions for …

Mars Sample Return Earth Entry System Uncertainty Analysis, Michael D. Squire, Victor Cabrera, Eric Christiansen, Alan Jenkin, Kevin Hoffman, Quincy Mckown, Peter Parker, Glenn Peterson, Bruno Victorino Sarli, William P. Schonberg, Katie Steward, Brian Tulaba, Joel Williamsen

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Spacecraft designers and operators use micrometeoroid and orbital debris (MMOD) risk assessments to predict the probability that an MMOD particle impact will cause a critical failure to their systems. An important aspect of MMOD risk and associated requirements is the treatment of uncertainty, often difficult to quantify, or even estimate, for many elements of MMOD risk. This paper describes recent efforts to estimate uncertainties in inputs to the MMOD risk assessment process for a portion of the planned Mars Sample Return (MSR) campaign. The uncertainty bounds developed were used to examine their effect on overall mission MMOD risk.

Analyzing Micrometeoroid And Orbital Debris Shield Performance For Sample Return Spacecraft, William P. Schonberg, Michael Squire

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Sample-return missions typically seek to collect and return samples from extraterrestrial locations to Earth for analysis. The return of samples from certain locations in the solar system represents a potential hazard to Earth's biosphere from foreign microorganisms. One way this could occur would be a break-up of the returning capsule during entry (which would disperse the samples through the air) due to undetected damage to the capsule thermal protection system (TPS). As a result, missions that plan to return payloads from some destinations are likely to have certain design requirements for the TPS surrounding their returning capsules, which may include …

Reduced Set-Shifting Processing Speed In Male Rats Following Low Dose (10 Cgy) Proton Exposure, Hui Ho Vanessa Chang, Gyutae Kim, Kyu-Sung Kim, Richard A. Britten

Center for Integrative Neuroscience and Inflammatory Diseases (CINID) Faculty Publications

Space radiation (SR) exposure poses significant biomedical risks, including effects on the central nervous system (CNS). These risks are particularly relevant to cognitive function during long-duration space missions. One critical cognitive skill is decision-making, which requires attentional set-shifting (ATSET)—the ability to quickly assess problems, evaluate options, and select the best actions. Previous studies have shown that exposure to However, the impact of low LET (< 1 keV/μm) protons, which significantly contribute to the total radiation flux astronauts encounter within spacecraft, on ATSET performance is unknown. To address this gap, we evaluated the effects of cranial irradiation with 10 cGy of 100 MeV/n protons (LET = 0.732 keV/μm) on ATSET performance in male Sprague-Dawley rats. We also investigated whether concurrent exposure to variable gravity (hypergravity step-up, step down, purported to have the same effect as exposure to microgravity (another major spaceflight stressor) exacerbated SR-induced cognitive deficits. Our findings indicate that proton exposure alone significantly impaired ATSET performance, as evidenced by decreased processing speed while performing compound discrimination reversal and extra-dimensional shifting. Notably, no additive or synergistic effects were observed when hypergravity was combined with proton exposure. The impact that low-dose proton exposure has on CNS functionality, particularly in reducing processing speed during complex tasks, warrant further investigation. If similar cognitive deficits were to occur in astronauts exposed to galactic cosmic rays, mission success and safety could be significantly compromised.

Fusion-Based Utilization And Synthesis Of Efficient Detections, Ethan C. Rogers, Parker H. Liberatore, Thomas G. James

Endeavors: Mississippi State Undergraduate Research Journal

This study aimed to develop hardware and software for an object detection fusion system, using three different sensors. The system was built and studied with the motivating application of autonomous drones searching for and detecting people in a search-and-rescue scenario. The system’s performance was compared to that of individual sensors deployed for the same task. The focus of the research was to prove the competence and benefits of a decision-level fusion method as it was applied to a lightweight object detection architecture, and the driving motivators behind the study were simplicity in implementation and good computational performance. In short, the …

Design Strategy For Hybrid Thrust Air Bearings: Comparative Analysis Of Rigid Vs. Foil Bearings Considering Optimum Taper Angle And Orifice Location With Experimental Validation, Ehiremen Ebewele

Mechanical and Aerospace Engineering Dissertations - Archive

Gas foil thrust bearings (GFTBs) are contactless bearings that offer advantages such as lightweight construction and the ability to accommodate misalignments and geometric irregularities. However, their load capacity is lower than rigid or magnetic bearings. The structure and geometry of the foil significantly influence GFTB performance. The taper-flat design is the most used configuration due to its effectiveness and ease of implementation. Key parameters in designing this geometry include taper ratio, taper height, orifice size, and orifice location. These parameters must be optimized alongside manufacturing constraints to produce an effective GFTB. This study presents a design optimization investigation of various …

Computational Study Of Detonation Wave Propagation And Propellant Injection In Detonation Engines, Jayson C. Small

Mechanical and Aerospace Engineering Dissertations - Archive

This research investigates the physics of detonation waves and their application to detonation engines, with two primary objectives: (1) to characterize detonation wave propagation, specifically detonation speed and wavefront thickness, in stoichiometric propane-oxygen mixtures near quenching conditions, and (2) to examine the physiochemical processes during propellant injection under detonation engine conditions, focusing on flush-wall-mounted, fluidic-valve injectors.

A multi-fidelity computational approach was employed. Reduced-order modeling based on the Chapman–Jouguet and Zeldovich–von Neumann–Doring models were used to evaluate detonation parameters and select an appropriate chemical mechanism. High-fidelity, multi-dimensional simulations solved the unsteady, compressible, reacting flows with finite-rate chemistry, using Reynolds-Averaged Navier–Stokes equations …