Aerospace Engineering Commons^™

Calculation Of Aerodynamic Surface Sensitivities Using The Adjoint Method In A Subsonic/Supersonic Panel Code, Nathan H. Hoch

All Graduate Theses and Dissertations, Fall 2023 to Present

An aircraft’s shape has a direct impact on the lift and drag it produces. In the early stages of designing an aircraft on a computer, engineers work to improve aircraft performance and efficiency by considering various shapes and configurations. Engineers use computer programs to analyze different designs and predict how each would perform in real-world conditions. Once an approximate aircraft shape is selected, adjustments to the shape can further improve the aircraft’s lift and drag characteristics. Engineers calculate a set of values called sensitivities that indicate which parts of the geometry should be changed to increase lift or reduce drag. …

Investigating Stability Of Cone-Derived Hypersonic Waverider Vehicles Via Design Space Exploration, Adam S. Weaver

All Graduate Theses and Dissertations, Fall 2023 to Present

It may come as no surprise that man-made objects flying at 5, 10, or even 25 the speed of sound (termed hypersonic) are difficult to design, inefficient in flight, and expensive to deploy. Most hypersonic vehicles are effectuated in ballistics, which simplify aerodynamic considerations owing to their fixed trajectory. However, maneuverable hypersonic vehicles can revolutionize commercial flight, national defense, and space travel. One candidate for such missions are waverider vehicles. Waverider vehicles cruise on a cushion of air generated by its own shock wave, essentially enjoying extra lift without any extra drag penalties (which are usually inherent to extra …

Effects Of The Gravity Gradient On The Path Of 1i/‘Oumuamua, Hannah R. Richardson

Honors Theses

In October 2017, the asteroid 1I/’Oumuamua first passed into viewing range [1]. The asteroid is notable for being the first interstellar object to enter the solar system. 1I/’Oumuamua was also unusual in its geometry; it is thought to have an aspect ratio of 6:1 and a length of approximately 400 m [2] [3]. The asteroid was observed to experience a non-Keplerian acceleration estimated to be on the order of 1⇥10−6 m s2 . Several theories have been proposed for the cause of this acceleration, all of which are non-gravitational in nature: volatile outgassing, photon pressure, and solar winds [1][4]. However, …

Exploring Metal Additive Manufacturing In Martian Atmospheric Environments, Zane Mebruer

Mechanical Engineering Undergraduate Honors Theses

On-surface manufacturing is key to the success of a planetary colonization, especially that of Mars. However, traditional subtractive manufacturing processes are equipment, energy, and material intensive, meaning novel additive manufacturing (AM) processes must be pursued for this end. Selective laser melting, one of the most effective and versatile AM methods, would be incredibly beneficial to a Martian mission but requires an artificial argon atmosphere to create effective parts. The purpose of this study was to examine if carbon dioxide, the gas that makes up over 95% of Mars’ surface atmosphere, would be a sufficient substitute for argon in SLM fabrication. …

Causes And Contributing Factors In General Aviation Fixed-Wing Stall And Spin Accidents, Lauren Westfall

Mechanical Engineering Undergraduate Honors Theses

General Aviation operations are all civil aviation operations excluding commercial airline operations and cargo transport. General Aviation accidents comprise approximately 94% of all aviation accidents in the United States annually. Stall and spin accidents are the third most common causes of fatal General Aviation accidents, accounting for 7.28% of such accidents in 2013–2022. The National Transportation Safety Board investigates and records all General Aviation accidents in the United States. Using the National Transportation Safety Board’s accident database, I investigated stall and spin accidents between 2013 and 2022 to find (1) the most common phases of flight where stall and spin …

Characteristics Of Patterned Surface Dielectric Barrier Discharge Devices For Ionic Wind Propulsion, Ethan J. Graef

Mechanical Engineering Undergraduate Honors Theses

Electroaerodynamic (EAD) or ionic wind propulsion is a growing area of research for small noiseless low speed aircraft. Previous flight demonstrations and experimentation have revealed that traditional methods of EAD propulsion utilizing corona discharge incur a large drag penalty due to their collector and emitter geometries. Recent publications detail flexible and geometrically conformable surface dielectric barrier discharge devices (SDBD) that could increase thrust and decrease drag as an ion source for an EAD propulsion system. This thesis explores the effects of different electrode sizes and geometries on total SDBD power consumption. SDBDs of a hexagonal, triangular, and square electrode geometry …

Advancing Additive Manufacturing For Extreme Environments Through Simulated Microgravity Printing, Laura Nayeli Molina

Open Access Theses & Dissertations

Additive Manufacturing (AM) holds significant potential for space exploration by enabling on-demand fabrication of components, reducing payload costs, and enhancing mission adaptability. However, microgravity introduces challenges in thermal regulation, material deposition, and structural integrity. This research explores the feasibility of submerged AM using neutral buoyancy in silicone oil to simulate microgravity conditions on Earth. A 3D printer was modified for submerged operation, with samples printed under three conditions: no oil (ambient air), submerged in oil, and simulated microgravity at varying temperatures. Mechanical tests, fracture surface analysis, and density measurements were performed to evaluate tensile strength, surface adhesion, and dimensional stability. …

Engineering Of Metallic Interpenetrating Phase Composites For The Control Of Deformation And Failure Modes During Dynamic Events, David Kiyoshi Santacruz

Open Access Theses & Dissertations

Aerospace components, automotive structures, and ballistics armor are all engineered to withstand high strain rate service events through a combination of material selection and design choices. However, structural components may be less effective when their implementation is constrained by other factors such as weight or design limitations. To meet these challenges, the development of next-generation materials will need to increasingly rely on composite material systems rather than monolithic materials. This thesis presents the fabrication, dynamic characterization testing, and post-mortem analysis of 316L/A356 interpenetrating phase composites (IPCs) made from the PrintCasting methodology. These composites consist of additively manufactured 316L stainless steel …

A Systems Engineering Approach For Mitigating Space Debris In Earth's Orbital Regimes, Manuel Soto

Open Access Theses & Dissertations

Space debris in Earth's orbital regimes is a complex threat that originates with human space activity and is maintained by Earth's gravitational force. Space debris poses the risk of colliding with and destroying operational space assets. These collisions, in turn, pose the risk of compounding space debris fragments by turning operational space entities involved in collisions into additional space debris. In other words, the space debris impact does not end with a fragment colliding with a space entity. Instead, the collision is a new space-debris birth since the entities colliding are likely to become multiple fragments. Depending on the collision's …

Stability Analysis Of Turbulent Fluid Flow, Adam D. Schroeder

Mathematics, Statistics, and Computer Science Honors Projects

Hydrodynamic stability refers to the study of when and how laminar flows transition to turbulence. This includes investigations of the mechanisms of transition, as well as the classification of known flow configurations as either stable or unstable and the identification of critical values of flow parameters at which this bifurcation occurs. In this thesis, we introduce the mathematical theory behind continuum mechanics and fluid dynamics as well as some tools from the study of dynamical systems. We apply these concepts to the linear stability analysis of zero pressure gradient flat plate flow via numerical simulations in OpenFOAM, discussing both the …

2025 Spring Graduate Recognition Program, Propulsion Research Center, Robert Frederick

PRC Graduate Recognition

This program includes the graduate recognition program for spring 2025. Includes photographs, upcoming events, recent publications, and student profiles.

Observing Mesospheric Gravity Waves With Nasa's Awe Mission And Correlating To Gnss Tec Maps, Jaime Aguilar Guerrero, Björn Bergsson, Sehin Mesfin, Pavel Inchin, Matthew Zettergren, Ludger Scherliess, Yucheng Zhao, Dominique Pautet

Space Dynamics Laboratory Publications

The Atmosphere Waves Experiment (AWE) is a NASA mission launched on November 9, 2023, and installed on the International Space Station (ISS). Its primary goal is to detect and characterize atmospheric gravity waves (AGWs) by measuring Earth’s mesospheric hydroxyl (OH) airglow with its key instrument, the Advanced Mesospheric Temperature Mapper (AMTM). Since its deployment, AWE has been quantifying the seasonal and regional variability of AGWs, investigating their occurrence and potential sources, and enabling the assessment of their broader impact on the atmosphere by comparing measurements at different altitudes by other instruments. AWE has collected extensive imagery and temperature data capturing …

Nonlinear Control System Design And Hardware Testing Of An Overactuated Multicopter, William A. Wearren

Graduate Theses and Dissertations (2019 - present)

For the concept of Urban Air Mobility to be implemented into everyday life, the safety of passengers, bystanders, and surrounding infrastructure needs to be held paramount [1]. In previous work done at the University of South Alabama Facility for Aerospace Systems and Technology (FAST) lab, a reconfigurable control law was derived and tested on a scratch built multicopter [2]. The goal of the control law was to stabilize an X8 model multicopter in the event of motor outages [2]. The control law was tested on a simulated model and flight tested on a small-scale X8 multicopter to verify the effectiveness …

Autonomous Control Of A Hybrid Unmanned Aerial Towed System On A Moving Platform, Zachary M. Miller

Graduate Theses and Dissertations (2019 - present)

With tethered rotor drones being more popular for aerial surveillance, moving platforms for tethered drones are being researched. However, these systems require constant power to the rotor drones for stabilization. With this difficulty in power consumption, a hybrid drone solution is presented. The hybrid drone is similar to an airplane, with quadcopter motors attached for stabilization and thrust when not moving.

The controller for the hybrid drone was tested and verified in simulation. The simulation of the system was built in Fortran and consists of a driver, a tether, and a hybrid drone. The driver was modeled after a generic …

An Msbe–Driven Advanced Air Mobility Post–Disaster Response System, Olabode A. Olanipekun

Graduate Theses and Dissertations (2019 - present)

In this work, an overarching conceptual design model towards the realization of a proposed Advanced Air Mobility Post–Disaster Response System (AAMPDR system) was explored through the focal lenses of systems thinking (ST), socio–technical systems (STS) and model–based systems engineering (MBSE) paradigms. Initially aimed at providing intervention for casualties and aerial support to emergency rescue workers on the ground in the event of a hurricane disaster around the Gulf shore of the Mobile bay area, Mobile city, AL., the scope of this research subsequently expanded to include a global outlook. Thereafter, culminating in the development of a generalized AAMPDR system model …

Implementation Of Unscented Kalman Filter-Based State Estimation For Multiple Spacecraft Using Global Positioning System Measurements, Bala Prenith Reddy Gopu

Theses and Dissertations

This study presents an implementation of state estimation for a drag-based rendezvous mission involving multiple chaser spacecraft and a single target, using Unscented Kalman Filtering (UKF) with Global Positioning System (GPS) measurements. The implemented method combines GPS navigation solutions with UKF to provide real- time state estimates of all spacecraft involved. Nonlinear least squares method is employed to process pseudorange and pseudorange rate measurements to determine receiver states, UKF utilizes these states as measurements to estimate absolute space- craft positions and velocities. This implementation also addresses practical challenges including raw GPS measurement processing, and varying GPS satellite geometries.

Experimental And Theoretical Fracture Analysis Of Additively Manufactured Orthotropic V-Notches, Venkata Siva Sainath Bavapuram

Theses and Dissertations

This study presents a comprehensive investigation into the fracture behavior of additively manufactured orthotropic V-notched components made of Acrylonitrile Butadiene Styrene (ABS) material. The research integrates both theoretical and finite element approaches to evaluate stress intensity factors (SIFs) in Modes-I and II, which are fundamental in characterizing stress field distributions around notches under applied loading conditions. Unlike isotropic materials, where stress fields depend only on geometry of the component, the anisotropic nature of 3D-printed ABS introduces a dependency on material properties that necessitate different approaches to include anisotropy of the material.

Tensile specimens are 3D-printed with specific material orientations to …

Developing End-To-End Imitation Learning For Asteroid Proximity Operations, Patrick David Quinn

Theses and Dissertations

Asteroid exploration remains a popular topic in the scientific community, however hurdles still exist for controlling spacecraft within the asteroid environment. Communication delays often require the usage of limited onboard computing hardware for navigation. Additionally, long mission timelines must be accommodated with highly efficient fuel use. Considering these issues, it is apparent that any guidance, navigation, and control (GNC) system in these spacecraft should emphasize both computational and fuel efficiency in its design. Furthermore, the integration of a robust state estimation system is necessary for the successful deployment of such systems. The development of a controller aiming to address these …

Towards Visual Inertial Navigation With Fixed Tetrahedral Targets, Joao Leonardo Silva Cotta

Theses and Dissertations

This dissertation presents a robust method for 6DoF position estimation under impaired visual conditions utilizing a minimum 4-point Perspective-n-Point (P4P) solver designed for tetrahedral targets. Using SO(3) × R 3 instead of SE(3), the method uses a Lie group-based formulation to discriminate between rotation and translation, thereby enabling computationally efficient, resource-conscious op- optimization while preserving correct geometric behavior. Designed using the contemporary C++17 library ShomerTarget, the solver is analytically formulated and assessed under pragmatic robotic conditions. Particularly in low-light and high-dynamic environments, experiments on embedded systems, UAVs, and NASA’s Astrobee show that the proposed solver attains enhanced accuracy compared to …

Mixed-Mode Fracture Analysis Of Additively Manufactured Periodic Orthotropic Functionally Graded Microcellular Materials, Behnam Shahbazian

Theses and Dissertations

The quest for safety, efficiency, and innovation in aerospace engineering demands a relentless focus on understanding how materials and structures behave under extreme and complicated loading conditions. Among the many challenges faced by engineers in this field, predicting and preventing structural failure stands out as both a fundamental necessity and a complex problem. Fracture mechanics, the science of how materials fail under stress, is a cornerstone of this effort. Whether it is the fuselage of an aircraft enduring cyclic loading or the lightweight components of a spacecraft resisting impact, the ability to accurately predict fracture behavior directly influences the reliability …