Engineering Commons^™

U.S. 5g Technology Policy: Competition Or Boycott?, Wes Ferguson, Kyle Vargus

Space and Defense

Rather than corral allies and partners across the globe into boycotting Chinese 5G telecommunication systems, U.S. officials should embrace free-and-fair trade competition against China, even in products and services where China may enjoy a technological lead.

The race for technological supremacy has emerged as a defining characteristic of the newest era of great power competition. China and the United States compete to become the dominant world power. Each side is racing to create the latest and most elite technologies to catapult themselves into the lead and give them the edge over their adversary. The fifth generation of wireless technology, called …

Atomic Assurance: Funding A Modern U.S. Test Readiness Program, Mark Tang

Space and Defense

To address intensified strategic competition with Russia and China, the United States should reinstate funding for a modern nuclear Test Readiness Program.

The U.S. has never faced the threat of two adversarial powers with nuclear arsenals that equal our own. With the emphasis on great power competition and mounting aggression by both China and Russia, the risk of conflict with either or both powers is growing. Currently, the U.S. is ill prepared for the possible existential challenge that is deterring conflict with two major nuclear peer adversaries. America’s defense strategy and approach towards the international order must change to protect …

Earth To Orbit: Three Models For Strengthening Space Deterrence, Anton Dahm

Space and Defense

Nuclear, cyber, and integrated deterrence models hold lessons for space deterrence strategy, including declared thresholds, resilient space architecture, and the embrace of international competition in technological innovation.

The United States depends heavily on space capabilities, significantly more than any other country. Not only does space enable navigation, communications, environmental monitoring, and other vital capabilities, but space has also been described as the most essential warfighting domain. However, the U.S. space architecture mirrors its early days: relying on important, expensive payloads on a limited number of satellites. While providing important capabilities to U.S. decision-makers, kinetic and non-kinetic weapons can easily target …

The German Zeitenwende: Turning Point Or Blind Alley?, Savannah Hollen

Space and Defense

The Zeitenwende, or turning point, announced by Chancellor Olaf Scholz after Russia’s invasion of Ukraine in February 2022, may end up leaving Germany with few good defense policy options.

After Russia’s invasion of Ukraine in 2022, Germany vowed to change course, to expand and modernize its military, which for decades has been weak relative to the size of Europe’s leading economy. As bold as Germany’s declarations have been, German leaders may well have walked into a blind alley, unsure of exactly how Zeitenwende will happen, what the final results will be, or the consequences if they never come close to …

Strategic Space Cooperation: U.S. Space Command And The National Guard’S State Partnership Program, David Moore, Jesse Morehouse, Patrick Mitchell

Space and Defense

In 2022, the U.S. Space Command (USSPACECOM) and the National Guard's State Partnership Program (SPP) began pursuing security cooperation objectives while integrating the space domain into greater deterrence efforts. As the newest combatant command (CCMD) with space as its Area of Responsibility (AOR), USSPACECOM has global strategic partnership interests and recognizes the value of the enduring relationships inherent in SPP. This cooperation allows the National Guard to offer its strong relationships, space expertise, and industry knowledge to USSPACECOM. This provides a foundation for USSPACECOM's security cooperation efforts. This article discusses the SPP's role in supporting USSPACECOM's engagement strategy and the …

Arms Control Optimism And Great Power Competition, Damon Coletta

Space and Defense

In its unjust war, Russia rakes at Ukrainian civilian targets using dual-capable missiles. China meanwhile tightens the screws on Taiwan as it cements its friendship with Russia and continues its buildup of strategic nuclear warheads.1 Conventional wisdom and U.S. policy under such tense conditions unduly discount expectations for arms control.2 Arms control, in the popular mind, centers on bans in testing or deployment, and is therefore terminally associated with disarmament. Trepidation about disarmament fuels assumptions in polarized democracy, and the United States in particular, about the narrow political conditions under which arms control can succeed during great power competition. Conventional …

Drone-Based, Boost-Phase Intercept Of North Korean Icbms, James D. Wells, William Priedhorsky, Frederick Lamb, Laura Grego

Space and Defense

North Korea currently has an adversarial relationship with the United States and has successfully tested both nuclear weapons and intercontinental-range ballistic missiles (ICBMs) capable of striking the continental United States.1 There are several ways the United States could attempt to address the threat posed by North Korea’s nuclear-armed ICBMs. Historically, the United States has relied on a policy of projecting military strength, fostering strong alliances, and maintaining a credible threat of retaliation to deter adversaries, including those with nuclear weapons, from initiating hostilities. Some have argued that this approach has been instrumental in preventing conflict between nuclear-armed nations, including North …

A Premature Obituary For Conventional Deterrence, Jeffery S. Lehmkuhl

Space and Defense

As the United States (US) continues to shift its weight of effort towards great power competition, some scholars and practitioners have questioned the relevance of conventional forces and their ability to deter. Chief among them is Sean McFate, who asserts that “conventional war is unicorn hunting” and that “no one fights that way anymore.”1 Jim Sciutto echoes McFate’s claims in his book The Shadow War and states that the US is losing to Russia and China in a new way of warfare that is conducted below the threshold of conventional warfare.2 Leading Russian General Valery Gerasimov furthered this claim when …

Nuclear Regimes In The 21st Century, Stephen J. Cimbala, Adam Lowther

Space and Defense

The modern nuclear operations practitioner is facing a more complex future than at any point since the height of the Cold War. Understanding the past, present, and possible future of nuclear force structure and doctrine offers the policy maker a useful way to make sense of unfolding events and place them within a broader context. With China, Russia, and North Korea all posing a growing nuclear risk to the United States, a strong grasp on the available options for countering these threats is certainly important.

Editor's Note, Damon Coletta

Space and Defense

No abstract provided.

Table Of Contents Vol. 15 No. 2

Space and Defense

No abstract provided.

Space And Defense Vol. 15 No. 2 Fall 2024 (Whole Issue)

Space and Defense

No abstract provided.

Heat Transfer In Tightly Packed Cylinder Arrays, Martin Kovachev

Doctoral Dissertations and Master's Theses

Cylindrical arrays with a cross flow are commonly used for heat transfer augmentation within an internal channel. In most applications, the cylinders have a spacing of over 2 diameters (2D) between their center points in both the lateral and downstream directions. One option for battery thermal management in hybrid/electric aviation is to use cylindrical batteries packed in arrays with an applied cross flow. In the context of aviation, it is important to maximize space and weight savings. Tightly packing these cylinder arrays with a spacing of under 2D in both directions would save on both of these yet have not …

A Low-Complexity Algorithm For Trajectory Generation In The Three-Body Problem, Brian P. Baker-Mcevilly

Doctoral Dissertations and Master's Theses

The Cislunar realm holds intrinsic value for scientific, commercial, and military applications as numerous entities have begun to invest resources into the expansion and utilization of the region. As the Cislunar region continues to grow, there is an escalating need for efficient methods of trajectory generation in this multi-body dynamical system for computationally limited systems. Thus, a low-complexity classical algorithm is proposed to achieve accurate orbital trajectories in the three-body problem. The proposed algorithm solves a polynomial interpolation problem, formulated using state measurements, through the unique decomposition of a dense system into sparse matrices. Several relevant Cislunar trajectories are simulated …

Nasa Microgreen Cultivation In Space Utilizing Pegda Hydrogels, Thomas Alarcon Ali, Zohaib Gabriel Khan, Ariel Marroquin, Samuel Martinez, Fabiha Samiha, Emily Yong

Publications and Research

During long-term space expeditions, it is crucial that astronauts receive the nutrients they need to maintain their overall health. While the current space diet of palatable foods is commendable and constantly evolving, nutritional content and food quality degrades over long durations. Microgreens are excellent candidates for space cultivation because they are nutrient-dense, young plants that are are densely grown and harvested when leaves are just emerging. However, antigravity, microgreen fragility, degradation speed, contamination, and limited water resources are substantial barriers to doing so. This study aims to address these challenges by cultivating microgreens inside a hydrogel, a soilless medium, to …

Aerodynamic Noise Reduction Of Wind Turbine Blades, Steven Davenport

Honors Theses

This project is presented to meet Western Michigan University’s College of Engineering and Applied Sciences Senior Design requirements. With wind turbines becoming increasingly popular as a form of energy generation, the need to reduce the aerodynamic noise is needed. Most commercial wind farms use turbines with a NACA 0012 airfoil. Thus, that is the only profile shape considered in this research. Seven modifications were made to a NACA 0012 airfoil to reduce aerodynamic noise. The airfoils were designed in SolidWorks and 3D printed at the WMU College of Aviation. The airfoils were simulated in Ansys Fluent and experimentally tested in …

Deployable Assembly Structure And Harnessing For A Langmuir Probe (Dash-Lp), Sean Cowell

Honors Theses

The nanosatellite being designed by the Western Aerospace Launch Initiative (WALI) will demonstrate the technology of single-polarity electrospray thrusters. Essential to the mission is the collection of information from the ionospheric plasma surrounding the CubeSat in Low Earth Orbit (LEO). Due to the plasma sheath generated by the spacecraft, a 1.75 m boom is required to extend the Langmuir probe (LP) outside of the region of disturbed plasma. This project, Deployable Assembly Structure and Harnessing for a Langmuir Probe (DASH-LP), developed components that accompany the boom deployment system. In particular, a cable stowage system to store the RG403 shielded triaxial …

Machine Visual Perception From Sim-To-Real Transfer Learning For Autonomous Docking Maneuvers, Derek Worth, Jeffrey Choate, Ryan M. Raettig, Scott L. Nykl, Clark N. Taylor

Faculty Publications

This paper presents a comprehensive approach to enhancing autonomous docking maneuvers through machine visual perception and sim-to-real transfer learning. By leveraging relative vectoring techniques, we aim to replicate the human ability to execute precise docking operations. Our study focuses on autonomous aerial refueling as a use case, demonstrating significant advancements in relative navigation and object detection. We introduce a novel method for aligning digital twins using fiducial targets and motion capture data, which facilitates accurate pose estimation from real-world imagery. Additionally, we develop cost-efficient annotation automation techniques for generating high-quality You Only Look Once training data. Experimental results indicate that …

Uncovering Upconversion Photoluminescence In Layered Pbi2 Above Room Temperature, Sharad Ambardar, Xiaodong Yang, Jie Gao

Mechanical and Aerospace Engineering Faculty Research & Creative Works

As a van der Waals (vdW) layered semiconductor material, lead iodide (PbI2) possessing a direct bandgap with strong photoluminescence emission in visible range has gained wide attention in applications of photonic and optoelectronic devices. Here, up conversion photoluminescence (UPL) in exfoliated PbI2 flakes is demonstrated at room temperature and elevated temperatures. The linear power dependence of UPL emission with 532 nm excitation suggests the one-photon involved multiphonon-assisted UPL emission process, which is revealed by the temperature-dependent UPL emission measurement. Meanwhile, the nonlinear power dependence of UPL emission with 561 nm excitation indicates the transition of UPL emission mechanism from linear …

The Integration And Validation Of A Class 3b Laser For Stereo Particle Imaging Velocimetry, Jensen Lam

Master's Theses

Particle Imaging Velocimetry (PIV) is a laser flow diagnostic measurement technique used to measure spatial and temporal velocity fields. In an effort to promote experimental aerodynamic research, specifically an entry point for students to learn Particle Imaging Velocimetry, an in-house Class 3B laser PIV system was developed and its experimental results were verified with a Class 4 laser. Both systems were integrated on the Cal Poly Water Tunnel Laboratory. The work emphasizes the application of lasers controlled by a micro-controller to perform microsecond-based pulses and integrating a newly-developed device with an old system consisting of software, cameras, and synchronizers. The …

An Investigation Into The Use Of Amateur Astronomy Equipment For Optical Orbit Determination Using A Mobile Telescope Platform, Johan C. Govaars

Master's Theses

The process of optical orbit determination has long been in the domain of large organizations and stationary observatories with highly specialized scientific equipment. This thesis seeks to determine not only if satellites can be captured regularly using purely commercial-off-the-shelf (COTS) equipment, but also if initial orbit determinations can be made using that data. Moreover, the use of a mobile telescope platform allows users to circumvent the restrictions of fixed observatories such as low horizon viewing restrictions or existing light pollution.

A completely COTS setup was utilized that included an 8-inch Celestron NextStar 8SE telescope with an f/6.3 focal reducer and …

Physics-Informed Deep Learning For Pilot Parameter Estimation And Pilot-Induced Oscillation Characterization, Stephen A. Brutch

Doctoral Dissertations and Master's Theses

This thesis investigates the issue of loss-of-control in flight which is a driving contributor to fatal aviation accidents. The two main contributors tackled in this research are human pilot error and categories of pilot-induced-oscillations. The primary objective is to develop models that can capture the mathematical parameters that relate to human pilot control under the widely used McRuer Mathematical pilot model. The goal is that if the mathematical parameters that relate to human pilot control can be monitored during flight then the pilot’s input to the control system and pilot-induced-oscillations (PIO) can be monitored during flight to avoid loss-of-control. This …

Assessing General Propulsion Architectures For Fast Transit Times To Mars For Crewed Missions, Vivek Bhatt

Doctoral Dissertations and Master's Theses

As NASA and commercial contractors, such as SpaceX, continue to develop their programs with Artemis and Starship, respectively, it is becoming more and more apparent that the program developments are ultimately for finding a way to put humans onto Mars. However, when we approach the current timeline of going to Mars, it usually involves a 6-9 month one way trip. Due to this, human spaceflight to Mars becomes more dangerous as exposure to affects such as solar radiation, long exposure to low gravity fields, and isolation. These are some of the many hazards that come with interplanetary space travel for …

Equivalent-Area Studies For Sonic Boom Loudness Mitigation On A Commercial Supersonic Aircraft Configuration, Zachary N. Foster

All Graduate Reports and Creative Projects, Fall 2023 to Present

Since the early 1970s, the FAA has banned commercial supersonic flight over populated areas. This ban has limited aerospace manufacturers’ and commercial aircraft companies’ ability to design and operate subsonic aircraft in their fleets. Since then, research has been conducted to understand the sonic boom and learn how to minimize its loudness. The work presented in this project report aims to use a 1D low-fidelity analysis to study the effect of perturbations to the outer mold line (OML) of a representative model of the N+2 Quiet Commercial Supersonic Concept Aircraft. Using a 1D analysis that employs an equivalent area method, …

Controller Software: Evolution, Identification, And Implementation, Balaji Balasubramaniam

Dissertations and Doctoral Documents, University of Nebraska-Lincoln, 2023–

In the annals of automation history and advancement, one can find control technology is at the core. Modern-day controllers rely heavily on software capability to provide stability and improve the system's performance. In particular, drone flight controllers use autopilot control software to accomplish autonomous navigation from take-off to landing. However, we know very little about how the controller code modifications and its impact, particularly at the software level. No general framework has been developed to identify the control code changes and observe the real values of software control loops at the kernel layer.

In this thesis, we lay the foundation …

Computational Investigation Of Boundary-Layer Transition Mechanisms In A Blunt Cone, Arturo Rodriguez

Open Access Theses & Dissertations

In this study, we have performed two-dimensional steady-state hypersonic CFD and one-and-two-dimensional steady-state heat conduction numerical simulations. We are using them to guide and study hypersonic boundary-layer transition ground testing physical experiments to be performed at Holloman High-Speed Test Track. We use surface heat transfer and fluid flow spot signatures to identify fluid flow regimes using laminar and turbulent numerical simulation solvers to understand boundary-layer transition thermocouple temperatures and fluid flow-forming structures. We have also analyzed the fluid flow in the geometries to be inviscid. We passed the CFD solution into the boundary-layer Harris code developed by NASA to explore …

Multiphysics Modeling And Experimental Validation Of High-Strength Steel In Laser Powder Bed Fusion Process, M. Rangapuram, S. Babalola, J. W. Newkirk, L. N. Bartlett, F. W. Liou, K. Chandrashekhara, Stephen R. Cluff

Materials Science and Engineering Faculty Research & Creative Works

Laser powder bed fusion (LPBF) is a subset of the additive manufacturing process in which a laser beam selectively joins the metal powder into a desired part in a sequential layer process. Owing to its complex nature of rapid heating and cooling of the melt pool, there is a need to understand the melt pool behavior and its effects on the final manufactured part. a densely packed powder bed is highly desirable for fabricating a superior part using the LPBF process. in this work, discrete element model was used to generate powder beds with realistic powder properties and various factors …

Biaxial Strain Tuned Upconversion Photoluminescence Of Monolayer Ws2, Shrawan Roy, Xiaodong Yang, Jie Gao

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Monolayer tungsten disulfide (1L-WS₂) is a direct bandgap atomic-layered semiconductor material with strain tunable optical and optoelectronic properties among the monolayer transition metal dichalcogenides (1L-TMDs). Here, we demonstrate biaxial strain tuned up conversion photoluminescence (UPL) from exfoliated 1L-WS₂ flakes transferred on a flexible polycarbonate cruciform substrate. When the biaxial strain applied to 1L-WS₂ increases from 0 to 0.51%, it is observed that the UPL peak position is redshifted by up to 60 nm% strain, while the UPL intensity exhibits exponential growth with the up-conversion energy difference varying from − 303 to − 120 meV. The measured …

2024 Summer-Fall Graduate Recognition Program, Propulsion Research Center, Robert Frederick

PRC Graduate Recognition

This program includes the graduate recognition program for summer and fall 2024. Includes photographs, upcoming events, recent publications, and student profiles.

Learning-Based Feature Identification For Rendezvous And Capture Of Non-Cooperative Space Objects, Trupti Mahendrakar

Theses and Dissertations

In recent years, On-Orbit Servicing (OOS) and Active Debris Removal (ADR) have attracted increasing interest due to growing concerns about space debris. This debris poses a significant risk to spacecraft, as collisions can catastrophically end missions and potentially trigger a cascading chain reaction of more debris. Space debris ranges from tiny paint chips to large non-functional spacecraft and even launch vehicle components. One way to mitigate the formation of additional space debris is to reduce the total number of large non-cooperative resident space objects present in operational orbits. This can be achieved through two approaches: de-orbiting these objects as part …