Aerospace Engineering Commons^™

Multi-Fidelity Machine Learning Modeling For Aerodynamic Response Prediction Of Aerospace Vehicles, Ethan S. Jackman

Theses and Dissertations

Hypersonic vehicle design requires understanding complex aerodynamic phenomena across the full flight regime. This study presents a novel MF surrogate modeling methodology that enables the prediction the full field response across a vehicle’s surface. A Space-Filling Curve (SFC) is used to convert unstructured data into 1D vectors. The a Convolutional Autoencoder is used with transfer learning to reduce the dimensionality of the data. An Emulator-Embedded Neural Network (E2NN) combines multi-fidelity data for fast, accurate predictions. A benchmark analytical example and hypersonic application are used to evaluate the methodology. Using various numbers of samples and sampling strategies it is found that …

Sparse-Data Orbit Estimation In Low Earth Orbit Using The Markov Chain Monte Carlo Ensemble Gaussian Mixture Filter, Nicholas J. Oden

Master's Theses

The number of space objects (SOs) in low Earth orbit (LEO) continues to increase rapidly, creating challenges for the current ground-based tracking network, which cannot accommodate the projected growth in SOs. Catalog maintenance relies on frequent observations for reliable reacquisition, with Two-Line Element (TLE) sets typically generated daily to mitigate rapid error growth from poor TLE accuracy. This constraint limits the ability to track more objects with existing infrastructure. This work evaluates the Markov Chain Monte Carlo Ensemble Gaussian Mixture Filter (MCMC EnGMF), a nonlinear, non-Gaussian filter well-suited for sparse tracking scenarios where higher post-update accuracy is needed to reduce …

Distributed Coherent Beamforming At 60 Ghz Enabled By Optically-Established Coherence, Drake Silbernagel, Yu Rong, Isabella Lenz, Prithvi Hemanth, Carl Morgenstern, Owen Ma, Nolan Matthews, Nadar Zaki, Kyle W. Martin, John D. Elgin, Jacob Holtom, Daniel W. Bliss, Kimberly Frey

Space Dynamics Laboratory Publications

We implement and experimentally demonstrate a 60 GHz distributed system leveraging an optical time synchronization system that provides precise time and frequency alignment between independent elements of the distributed mesh. Utilizing such accurate coherence, we perform receive beamforming with interference rejection and transmit nulling. In these configurations, the system achieves a coherent gain over an incoherent network of N nodes, significantly improving the relevant signal power ratios. Our system demonstrates extended array phase coherence times, enabling advanced techniques. Results from over-the-air experiments demonstrate a 14.3 dB signal-to-interference-plus-noise improvement in interference-laden scenarios with a contributing 13.5 dB null towards interference in …

Mesospheric Gravity Waves Observed By Nasa Atmospheric Waves Experiment (Awe), Yucheng Zhao, Jiarong Zhang, Pierre-Dominique Pautet, Jun Ma, Joe Mcinerney, Hanli Liu, Steve Eckermann, Ludger Scherliess, Michael John Taylor, Burt Lamborn, Russ Kirkham

Space Dynamics Laboratory Publications

Although smaller scale gravity waves (GWs) (horizontal wavelengths ~30–300 km) are thought to account for the dominant energy and momentum inputs at the Ionosphere-Thermosphere-Mesosphere (ITM) altitudes, the sources, variability, and influences of these smaller-scale GWs are still major unknowns. The NASA Atmospheric Waves Experiment (AWE) is designed to measure these GWs in the mesopause region. In November 2023, AWE was successfully launched and deployed on the International Space Station (ISS) and science data collection was started. The AWE instrument maps the nighttime hydroxyl (OH) layer (~87 km), providing 2D GW fields in mesospheric temperature and OH band intensity over a …

Orographic Wave Activity At Mesospheric Altitude Over The Southern Ocean Islands Observed By The Atmospheric Waves Experiment, P.-D. Pautet, S. D. Eckermann, L. Scherliess, J. Ma, Y. Zhao

Space Dynamics Laboratory Publications

A major source for the gravity waves (GW) measured in the stratosphere and higher is the orographic forcing produced by the tropospheric wind blowing over mountainous regions. Recent studies have shown that even small islands can generate waves which, under appropriate conditions, are able to penetrate above 80 km altitude, transporting large amount of momentum into the upper atmosphere. Investigating the exact effects of those islands is challenging because ground-based and even airborne measurements are limited above those generally isolated places.

The Utah State University (USU) Atmospheric Waves Experiment (AWE) was designed and built to study mesospheric GW globally, even …

Tensile Creep Of A Hybrid Polymer-Matrix/Ceramic-Matrix Composite At Elevated Temperature, Waleed S. Alshehri

Theses and Dissertations

Advanced aerospace systems require structural materials that can perform reliably in high-temperature environments for long durations. The performance of standard polymer matrix composites (PMCs) in these conditions is often limited by their susceptibility to time-dependent deformation, such as creep. The objective of this research is to characterize the high-temperature creep behavior of a novel unitized material system comprising a polymer matrix composite (PMC) and a ceramic matrix composite (CMC) co-cured together. The PMC part consists of the polyimide matrix reinforced with laminated carbon fibers woven in an eight harness satin weave (8HSW). The CMC part consists of a zirconia-based ceramic …

Low-Cost Transfers For Cislunar Liaison Navigation, Ka'eo J. Swartzmiller

Theses and Dissertations

CubeSats have an inherent limitation on volume due to their small form factor. Naturally, this extends to the capacity of on-board ΔV, thus limiting the maneuverability of the satellites. This limited maneuverability makes it extremely important to be intentional when planning out mission trajectories. The cislunar region subjects these trajectories to the gravitational forces of both the Earth and the Moon, making it all the more necessary to deliberately plan out maneuvers. The Circular Restricted Three Body Problem (CR3BP) provides a simpler model for estimating the motion of spacecraft within the cislunar region, allowing for the gravitational forces to be …

Reduced Order Models Of Hydrodynamically Interacting Flapping Wings, Jose Pabon

Dissertations

Fish schools exhibit a collective behavior and self-organization that is mediated by hydrodynamic interactions between individual fish. However, the long-time evolution of hydrodynamically interacting collectives is challenging to investigate due to the persistent influence of long-lived vortical structures, and the high-resolution requirements of direct numerical simulation at large Reynolds numbers. Reduced-order models have therefore played an important role in theoretical investigations of collectives of swimming bodies. The main results detailed herein are several new reduced-order models of swimmers that self-propel by flapping, i.e., by executing a prescribed periodic rigid body motion. The models are extensions of a discrete-time dynamical system …

Lifting-Line Predictions For Optimal Dihedral Distributions In Ground Effect, Amanda K. Olsen, Zachary S. Montgomery, Douglas F. Hunsaker

Mechanical and Aerospace Engineering Student Publications and Presentations

When a flying wing comes within close proximity to the ground, a phenomenon called ground effect occurs where the lift is increased and the induced drag is decreased. This research seeks to determine the optimal dihedral distribution predicted by lifting-line theory that minimizes induced drag in ground effect. Despite some limitations, using lifting-line theory for this study allows for quick results across a large range of design variables, which would be infeasible for high-fidelity methods. The SLSQP optimization method is used along with a numerical lifting-line code to find the dihedral distribution that minimizes induced drag. Results are presented showing …

Grain Size- And Temperature-Dependent Phonon-Mediated Heat Transport In The Solid Electrolyte Interphase: A First-Principles Study, Arjun S. Kulathuvayal, Yanqing Su

Mechanical and Aerospace Engineering Student Publications and Presentations

The solid electrolyte interphase (SEI) is a passive layer, typically a few hundred angstroms thick, that forms on the electrode surface in the first few battery cycles when the electrode is in contact with the electrolyte in lithium-metal batteries. Composed of a combination of lithium salts and organic compounds, the SEI plays a critical role in battery performance, serving as a channel for Li-ion shuttling. Its structure typically comprises an inorganic component-rich sublayer near the electrode and an outer organic component-rich sublayer. Understanding heat transport through the SEI is crucial for improving battery pack safety, particularly since the Li-ion diffusion …

Contributing Factors To Low Airspeed On Climb-Out As A Precursor To Loss Of Control In Flight, Owen D. Poborsky

Journal of Aviation Technology and Engineering

The nature of aviation is not without inherent risk. Conducting training flight operations increases these inherent risks. Flight data monitoring and voluntary safety action programs seek to reduce risk, as seen in their success at commercial airlines. These successes are slowly permeating into general aviation through programs such as the National General Aviation Flight Information Database (NGAFID). The NGAFID is a program funded by the Federal Aviation Administration that allows general aviation operators to have the ability to collect and share de-identified flight data on an aggregate level to identify trends and increase safety margins during flight operations. This study …

Resolvent-Based And Data-Driven Analysis Of A Supersonic Rectangular Multistream Jet, Miteshkumar Thakor

Dissertations - ALL

Coherent structures play a key role in uncovering and predicting the underlying physics of complex turbulent flows. This dissertation employs data-driven and operator-based techniques to investigate spatiotemporal correlated structures of a complex supersonic multi-stream rectangular jet. The nozzle configuration comprises three primary shear layers: (i) an upper shear layer (USL) formed by the flow on the upper single-sided expansion ramp stream and the freestream, (ii) a splitter plate shear layer (SPSL) generated by the mixing of a core Mach 1.23 stream with a bypass Mach 1 stream at the splitter plate trailing edge (SPTE) and (iii) a lower shear layer …

Defending Nato’S Northern Flank: Power Projecting And Military Operations, Nate Ostdiek

Space and Defense

This review evaluates Defending NATO’s Northern Flank: Power Projection and Military Operations, edited by Lon Strauss and Njord Wegge. The volume offers a comprehensive assessment of NATO’s evolving Arctic posture, combining doctrinal analysis, historical context, and alliance dynamics. Contributions examine Russia’s military strategy, U.S. Arctic policy, and intra-alliance complexities involving Denmark, Greenland, and the Faroe Islands. While the anthology provides valuable insights into NATO’s strategic challenges, it notably underrepresents Canada’s role. Overall, it stands as a timely and rigorous contribution to understanding Arctic security and NATO’s internal decision-making amid rising geopolitical competition.

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Modeling Nato Joint Warfighting Through Space Combat Simulations, Grant Nehls, Apoorva Somani

Space and Defense

This article investigates NATO’s dependence on space systems in joint warfighting and explores the use of simulation to quantify degradation effects. Using a custom-built AFSIM model of a NATO Arctic operation, the study demonstrates how GNSS spoofing and crosslink jamming undermine data integrity, commander trust, and strike execution—even without kinetic losses. Results show that partial degradations can cause mission failure through decision paralysis. By moving beyond binary modeling, this research highlights the need for nuanced simulations to prepare NATO for contested space environments and the challenges of great power competition.

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From The Last Frontier To The Final Frontier: The Polar Regions And Space Security, Michael Lynch

Space and Defense

This article examines the intersection of Arctic geopolitics and space security amid intensifying U.S., Russian, and Chinese competition. Melting ice has opened access to resources and new sea routes, elevating the Arctic’s strategic value while increasing reliance on space-based communications, navigation, and surveillance. Yet, vulnerabilities in polar orbits, aging ground infrastructure, and dual-use facilities expose critical systems to environmental hazards and geopolitical risks. The analysis highlights modernization efforts—including SHIELD and Golden Dome—as well as enduring cooperation and rivalries, underscoring the Arctic’s role as both a frontier of opportunity and a potential flashpoint in space-enabled security.

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Same But Different: The Survivability Of Arctic-Based Russian Second-Strike Capability, July Decarpentrie

Space and Defense

This article analyzes the survivability of Russia’s second-strike capability in the Arctic through the lens of classical nuclear deterrence theory. Despite heavy commitments in Ukraine, Moscow continues to modernize its Northern Fleet and reinforce bastion defenses, underscoring the Arctic’s role as the cornerstone of its retaliatory deterrent. While these strategies mirror Cold War practices, they face unprecedented challenges from NATO expansion, multipolar competition, and advances in anti-submarine detection technologies. The study concludes that safeguarding Russia’s second-strike capability not only shapes regional security dynamics but also has broader implications for global strategic stability.

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Atomic Offsets: Nuclear Policy Shifts For Arctic States In The Wake Of Moscow’S Special Military Operation, Molly Wise, Lillian Hussong

Space and Defense

This article examines how Russia’s 2022 invasion of Ukraine has intensified nuclear reliance among Arctic states. Applying a new framework of “conventional-nuclear vulnerability,” it analyzes the nuclear policy shifts of Sweden, Finland, and Russia. The findings show that Finland and Sweden pursued NATO membership to secure nuclear guarantees, while Russia adopted riskier nuclear signaling and lowered thresholds for nuclear use. These developments highlight the growing centrality of nuclear deterrence in Arctic security, underscoring the challenges for U.S. and NATO policymakers in balancing assurance and deterrence in a volatile regional environment.

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Russian Strategic Culture And Deterrence In The Arctic, Lana Obradovic, Bethany Vailliant

Space and Defense

This study analyzes Russia’s evolving strategic culture to assess its implications for deterrence in the Arctic. It argues that Western deterrence frameworks insufficiently account for Russia’s integration of military, economic, informational, and political tools into a holistic strategy. Rooted in a siege mentality and aspirations for great power status, Russia perceives the Arctic as central to its security, economic modernization, and geopolitical influence. By situating Arctic policy within this cultural framework, the analysis highlights the need for U.S. and NATO practitioners to reassess assumptions and develop more culturally attuned deterrence strategies.

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Table Of Contents Vol. 16 No. 1, Editors Space And Defense

Space and Defense

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Front Matter, Editors Space And Defense

Space and Defense

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