Aerospace Engineering Commons^™

Navigational Feasibility Of Flyby / Impact Missions To Interstellar Objects, Declan Moore Mages

Master's Theses

In October 2017, the first interstellar object, designated 1I/2017 U1 and more commonly referred to as Oumuamua, was detected passing through our solar system by the Pan-STARRS telescope, followed recently by the detection of 2I/Borisov in August 2019. These detections came much sooner than thought possible, and have redefined our understanding of the population of interstellar objects. With the construction of the next generation of powerful observatories, future detections are estimated to occur as frequently as two per year, and while there is significant scientific understanding to be gained from observing these objects remotely, a spacecraft sent to intercept one …

Modeling And Testing Powerplant Subsystems Of A Solar Uas, Luke J. Bughman

Master's Theses

In order to accurately conduct the preliminary and detailed design of solar powered Unmanned Aerial Systems (UAS), it is necessary to have a thorough understanding of the systems involved. In particular, it is desirable to have mathematical models and analysis tools describing the energy income and expenditure of the vehicle. Solar energy income models may include available solar irradiance, photovoltaic array power output, and maximum power point tracker efficiency. Energy expenditure models include battery charging and discharging characteristics, propulsion system efficiency, and aerodynamic efficiency. In this thesis, a series of mathematical models were developed that characterize the performance of these …

Development Of A Tailored Flight Test Approach For Small Unmanned Aircraft Systems, Neil A. Wolfe

Master's Theses

This document contains the details of a study conducted to determine an effective performance flight test approach specifically for small Unmanned Aircraft Systems (sUAS). This was done by taking proven procedures and documentation from the FAA and the Air Force for manned aircraft and tailoring them specifically for use with sUAS flight test programs. A ‘sUAS Flight Testing Handbook’ was created from the proceedings to aid commercial organizations and recreational developers conducting sUAS research without access to flight test experience. A performance flight test program was conducted with the AeroVironment RQ-20 Puma sUAS using the developed approach to verify that …

Cubesat Astronomy Mission Modeling Using The Horizon Simulation Framework, Alexander W. Johnson

Master's Theses

The CubeSat Astronomy Network is a proposed system of multiple CubeSat spacecraft capable of performing follow-up observations of astronomical targets of interest. The system is intended to serve as a space-borne platform that can complement existing systems utilized for astronomical research by undergraduate and high school students. Much research and development work has been performed to develop model-based system engineering methodologies and products for CubeSat missions, including the Horizon Simulation Framework. The Horizon Simulation Framework enables the development of system models using the Extended Markup Language (XML), and its simulation program can generate system simulations over model-specified timespans. System requirements …

Investigation Of The Under-Body Flow Field Of A Prototype Long-Range Electric Vehicle, Matthew P. Nguyen

Master's Theses

This thesis presents changes to the design of the Prototype Vehicles Laboratory (PROVE Lab) Endurance Car, an electric car intended to break the Guinness World Record for the single-charge range of an electric vehicle. The design range is 1609.34 km, however at the design velocity of 104.6 kph, the drag is 196 N; which requires more battery capacity than the 100 kWh maximum of the baseline model. With a fixed frontal area, drag reduction can come from lowered velocity or reduced CD. CD reduction is attempted in four ways: side skirts between the fenders, a raised ride height, an elongated …

Experimental Investigation Into Utilizing Synthetic Jet Actuators To Suppress Bi-Modal Wake Behavior Behind An Ahmed Body, Daniel Jacob Baratta

Master's Theses

Testing done on the flat-back Ahmed Body and other bluff bodies has shown the existence of a bi-stable reflectional symmetry-breaking wake at Reynolds numbers ranging from 340 to 2.41 x 10⁶. Several methods of flow control, both active and passive, have been used to improve the efficiency of the Ahmed body but their effect on the bi-stable nature of the wake has not been investigated. This work details the experimental investigation done to determine if piezoelectrically driven synthetic jet actuators are capable of suppressing the bi-stable wake effects observed behind the Ahmed Body. The synthetic jets were designed …

A Comparison Of Crushing Parameters Of Graphite Composite Thin-Walled Cylinders Cured In Low And High Pressures, Trenton John Matson

Master's Theses

Out-of-Autoclave (OoA) processes for manufacturing aerospace-grade parts needs to be better understood to further the development and success of industries that are manufacturing reusable launch vehicles, military and commercial aircraft, and spacecraft. Overcoming the performance limitations associated with OoA, also known as low-pressure prepreg curing, methods (void count, energy absorption, etc.) will help decrease the costs associated with aerospace composite manufacturing and the negative environmental effects correlated with high-pressure composite curing methods. Experimental, theoretical, and numerical approaches are used to explore both low and high-pressure curing cycles and how the two different processes affect final cured parts. Quasi-static uniaxial compression …

The Effects Of Atomic Oxygen On Patch Antenna Performance And Lifetime, Max J. Barta

Master's Theses

The space environment is a volatile and challenging place for satellites to survive in. For Low Earth Orbiting (LEO) satellites, atomic oxygen (AO) is a constant corrosive effect that degrades the outer surface of satellites over long durations. Atomic oxygen exists in the atmosphere between 180 and 675 km and has a relatively high energy at 4.5 eV, which allows AO to break molecular bonds in materials on the surfaces of spacecraft. As the number and complexity of CubeSat missions increase, there is an increased risk that AO degradation on commercial off the shelf parts (COTS), such as antenna, could …

Design Principles And Preliminary Testing Of A Micropropulsion Electrospray Thruster Research Platform, Will Alan Mcgehee

Master's Theses

The need for micropropulsion solutions for spacecraft has been steadily increasing as scientific payloads require higher accuracy maneuvers and as the use of small form-factor spacecraft such as CubeSats becomes more common. Of the technologies used for this purpose, electrospray thrusters offer performance that make them an ideal choice. Electrosprays offer high accuracy impulse bits at low power and high efficiency, and have low volume requirements. Design choice reasoning and preliminary testing results are presented for two electrospray thruster designs. The first thruster, named the Demonstration thruster, is operated in atmospheric conditions and serves as a highly visible example of …

Colloid Thruster To Teach Advance Electric Propulsion Techniques To Post-Secondary Students, Alexander M. Powaser

Master's Theses

Colloid thrusters, and electrospray thrusters as a whole, have been around since the 1960s. When they were first developed, the high efficiency and fine thrust control was overshadowed by the high power requirement for such a low thrust that the system provides. This caused the technology to be put on hold for aerospace applications. Now, as small satellites are becoming more prevalent, there has been a resurgence in interest in electrospray thruster technology. The recent advancements in tech- nology allow electrospray thrusters to use significantly less power and occupy less volume than their predecessors. As electrospray technology continues to advance, …

Atomic Oxygen Effects On Particulate Contamination And Short Beam Strength Of Carbon Composites, Marlee K. Litzinger

Master's Theses

In order to design a successful space system, the unique challenges of the space environment it will operate in must be considered during the design process. Atomic oxygen (AO) is a detrimental environmental effect found in Low Earth Orbit (LEO) that affects spacecraft surfaces by oxidizing and eroding material over time, particularly polymers. Carbon fiber/epoxy composites are a commonly used spacecraft material affected by AO exposure. Carbon composites are used as a structural material, such as on solar panels; their large surface area therefore is a potential contamination source to sensitive components. The Space Environments and Testing Lab at California …

Effects Of Corrugations On Stiffness Properties Of Composite Beams For Structural Applications, Jane Xiao

Master's Theses

Composites have high strength-to-weight ratios, which is particularly desired for applications with weight restrictions. Common composite materials such as carbon fiber reinforced plastic (CF) and fiber glass reinforced plastic (FG) were used in this research. While composite materials possess high stiffness and strength properties, the stiffness of composite laminates may be maximized by changing the geometry. By adding corrugations, the flexural stiffness is increased in one direction compared to the stiffness of a flat part with the same amount of material. Thus, stiffness increases without a change in weight. The primary goal of this research was to investigate the stiffness …

A Homegrown Dsmc-Pic Model For Electric Propulsion, Dominic Charles Lunde

Master's Theses

Powering spacecraft with electric propulsion is becoming more common, especially in CubeSat-class satellites. On account of the risk of spacecraft interactions, it is important to have robust analysis and modeling tools of electric propulsion engines, particularly of the plasma plume. The Navier-Stokes equations used in classic continuum computational fluid dynamics do not apply to the rarefied plasma, and therefore another method must be used to model the flow. A good solution is to use the DSMC method, which uses a combination of particle modeling and statistical methods for modeling the simulated molecules. A DSMC simulation known as SINATRA has been …

Sweep And Taper Analysis Of Surfboard Fins Using Computational Fluid Dynamics, Brandon James Baldovin

Master's Theses

The research presented here provides a basis for understanding the hydrodynamics of surfboard fin geometries. While there have been select studies on fins there has been little correlation to the shape of the fin and its corresponding hydrodynamic performance. This research analyzes how changing the planform shape of a surfboard fin effects its performance and flow field. This was done by isolating the taper and sweep distribution of a baseline geometry and varying each parameter individually whilst maintaining a constant span and surface area. The baseline surfboard fin was used as a template in Matlab to generate a set of …

A Higher-Order Method Implemented In An Unstructured Panel Code To Model Linearized Supersonic Flows, Jake Daniel Davis

Master's Theses

Since their conception in the 1960s, panel codes have remained a critical tool in the design and development of air vehicles. With continued advancement in computational technologies, today's codes are able to solve flow fields around arbitrary bodies more quickly and with higher fidelity than those that preceded them. Panel codes prove most useful during the conceptual design phase of an air vehicle, allowing engineers to iterate designs, and generate full solutions of the flow field around a vehicle in a matter of seconds to minutes instead of hours to days using traditional CFD methods. There have been relatively few …

Effect Of Aerogel On The Thermal Performance Of Corrugated Composite Sandwich Structures, Jacob Dillon Chess

Master's Theses

Current insulation solutions across multiple industries, especially the commercial sector, can be bulky and ineffective when considering their volume. Aerogels are excellent insulators, exhibiting low thermal conductivities and low densities with a porosity of around 95%. Such characteristics make aerogels effective in decreasing conductive heat transfer within a solid. These requirements are crucial for aerospace and spaceflight applications, where sensitive components exist among extreme temperature environments. When implemented into insulation applications, aerogel can perform better than existing technology while using less material, which limits the amount of volume allocated for insulation. The application of these materials into composites can result …

Generating Exploration Mission-3 Trajectories To A 9:2 Nrho Using Machine Learning, Esteban Guzman

Master's Theses

The purpose of this thesis is to design a machine learning algorithm platform that provides expanded knowledge of mission availability through a launch season by improving trajectory resolution and introducing launch mission forecasting. The specific scenario addressed in this paper is one in which data is provided for four deterministic translational maneuvers through a mission to a Near Rectilinear Halo Orbit (NRHO) with a 9:2 synodic frequency. Current launch availability knowledge under NASA’s Orion Orbit Performance Team is established by altering optimization variables associated to given reference launch epochs. This current method can be an abstract task and relies on …

Micro-Nozzle Simulation And Test For An Electrothermal Plasma Thruster, Tyler J. Croteau

Master's Theses

With an increased demand in Cube Satellite (CubeSat) development for low cost science and exploration missions, a push for the development of micro-propulsion technology has emerged, which seeks to increase CubeSat capabilities for novel mission concepts. One type of micro-propulsion system currently under development, known as Pocket Rocket, is an electrothermal plasma micro-thruster.

Pocket Rocket uses a capacitively coupled plasma, generated by radio-frequency, in order to provide neutral gas heating via ion-neutral collisions within a gas discharge tube. When compared to a cold-gas thruster of similar size, this gas heating mechanism allows Pocket Rocket to increase the exit thermal velocity …

Investigating The Effect Of An Upstream Spheroid On Tandem Hydrofoils, Joel Tynan Guerra

Master's Theses

This thesis documents a series of three dimensional unsteady Reynolds Averaged Navier-Stokes CFD simulations used to investigate the influence of an upstream prolate spheroid body on tandem pitching hydrofoils. The model is validated by performing separate CFD simulations on the body and pitching hydrofoils and comparing results to existing experimental data. The simulations were run for a range of Strouhal numbers (0.2-0.5) and phase differences (0-π). Results were compared to identical simulations without an upstream body to determine how the body affects thrust generation and the unsteady flow field.

The combined time-averaged thrust increases with Strouhal number, and is highest …

Nanosatellite Launch Data-Logger (Sync), Christopher Martin Gerdom

Master's Theses

CubeSat designers are increasingly looking to incorporate delicate structures and optics into their payloads. These delicate payloads, however, may not survive the required absolute-worst-case launch vibration testing needed for flight certification. To help address this problem, and to better match testing conditions to real-world launch environments, this thesis introduces Sync, a compact 1/4U CubeSat payload designed to collect data on the vibrations and thermal environments CubeSats experience inside a deployer on the way to orbit. This data can be used to better understand the launch environment for different vehicles, and help develop new, more realistic testing guidelines that could enable …

Comparative Analysis Of Electrodynamic Toroidal Radiation Shielding Configurations, Max Rosenberg

Master's Theses

Beyond the protective confines of Earth's atmosphere and magnetosphere, spacecraft are subject to constant bombardment by high-energy charged particles originating from our Sun in the form of Solar Particle Events (SPEs), and from outside the solar system in the form of Galactic Cosmic Rays (GCRs). The harm these particles do can be reduced or mitigated outright through radiation shielding. Because protons and other charged particles comprise most of these radiation particles, strong magnetic fields could be generated around spacecraft to deflect incoming charged radiation particles. This thesis investigates the performance of specific configurations of toroidal superconducting solenoids to generate magnetic …

A Computational Fluid Dynamics (Cfd) Analysis Of The Aerodynamic Effects Of The Seams On A Two-Dimensional Representation Of A Soccer Ball, Allen R. Rohr

Master's Theses

Most major sports today use a dedicated ball or projectile with specific shape, size, and surface geometry, except for soccer. Over the history of the sport, the surface geometry and design stayed relatively unchanged, sewn together using 32 pentagonal and hexagonal panels. However, recent innovations in panel designs differ substantially from the traditional 32 panel ball. The effects these new designs have on the aerodynamic characteristics of the ball have remained largely unknown, even with the influx of experimental research completed in the past decade. Experimental studies have been broad in scope, analyzing an entire ball in wind tunnels or …

Bi-Stability In The Wakes Of Platooning Ahmed Bodies, Daniel M. Stalters

Master's Theses

Autonomous heavy vehicles will enable the promise of decreased energy consumption through the ability to platoon in closer formation than is currently safe or legal. It is therefore increasingly important to understand the complex and dynamic wake interactions between vehicles operating in close proximity for aerodynamic gains. In recent years, a growing body of research has documented a bi-stable, shifting wake generated behind the Ahmed reference bluff body. At the same time, studies of platooning Ahmed bodies have focused on changes to the body forces and moments at different following distances or lateral offsets, typically based around time-averaged measurements or …

The Development And Validation Of Sinatra: A Three-Dimensional Direct Simulation Monte Carlo (Dsmc) Code Written In Object-Oriented C++ And Performed On Cartesian Grids, David Matthew Galvez

Master's Theses

The field of Computational Fluid Dynamics (CFD) primarily involves the approximation of the Navier-Stokes equations. However, these equations are only valid when the flow is considered continuous such that molecular interactions are abundant and predictable. The Knudsen number, $Kn$, which is defined as the ratio of the flow's mean free path, $\lambda$, to some characteristic length, $L$, quantifies the continuity of any flow, and when this parameter is large enough, alternative methods must be employed to simulate gases. The Direct Simulation Monte Carlo (DSMC) method is one which simulates rarefied gas flows by directly simulating the particles that compose the …

An Evaluation Of Ultrasonic Shot Peening And Abrasive Flow Machining As Surface Finishing Processes For Selective Laser Melted 316l, Rhys Gilmore

Master's Theses

Additive Manufacturing, and specifically powder bed fusion processes, have advanced rapidly in recent years. Selective Laser Melting in particular has been adopted in a variety of industries from biomedical to aerospace because of its capability to produce complex components with numerous alloys, including stainless steels, nickel superalloys, and titanium alloys. Post-processing is required to treat or solve metallurgical issues such as porosity, residual stresses, and surface roughness. Because of the geometric complexity of SLM produced parts, the reduction of surface roughness with conventional processing has proven especially challenging. In this Thesis, two processes, abrasive flow machining and ultrasonic shot peening, …

Orbital Constellation Design And Analysis Using Spherical Trigonometry And Genetic Algorithms: A Mission Level Design Tool For Single Point Coverage On Any Planet, Joseph R. Gagliano

Master's Theses

Recent interest surrounding large scale satellite constellations has increased analysis efforts to create the most efficient designs. Multiple studies have successfully optimized constellation patterns using equations of motion propagation methods and genetic algorithms to arrive at optimal solutions. However, these approaches are computationally expensive for large scale constellations, making them impractical for quick iterative design analysis. Therefore, a minimalist algorithm and efficient computational method could be used to improve solution times. This thesis will provide a tool for single target constellation optimization using spherical trigonometry propagation, and an evolutionary genetic algorithm based on a multi-objective optimization function. Each constellation will …

Investigating Forward Flight Multirotor Wind Tunnel Testing In A 3-By 4-Foot Wind Tunnel, Reed Danis

Master's Theses

Investigation of complex multirotor aerodynamic phenomena via wind tunnel experimentation is becoming extremely important with the rapid progress in advanced distributed propulsion VTOL concepts. Much of this experimentation is being performed in large, highly advanced tunnels. However, the proliferation of this class of vehicles extends to small aircraft used by small businesses, universities, and hobbyists without ready access to this level of test facility. Therefore, there is a need to investigate whether multirotor vehicles can be adequately tested in smaller wind tunnel facilities. A test rig for a 2.82-pound quadcopter was developed to perform powered testing in the Cal Poly …

Use Of Manifolds In The Insertion Of Ballistic Cycler Trajectories, Oliver K. Morrison

Master's Theses

Today, Mars is one of the most interesting and important destinations for humankind and copious methods have been proposed to accomplish these future missions. One of the more fascinating methods is the Earth-Mars cycler trajectory which is a trajectory that accomplishes repeat access to Earth and Mars with little to no fuel-burning maneuvers. This would allow fast travel to and from Mars, as well as grant the possibility of multiple missions using the same main vehicle.

Insertion from Earth-orbit onto the cycler trajectory has not been thoroughly ex- plored and the only existing method so far is a Hohmann-esque transfer …

Electrode Geometry Effects In An Electrothermal Plasma Microthruster, Harrison Raymond King

Master's Theses

Nanosatellites, such as Cubesats, are a rapidly growing sector of the space industry. Their popularity stems from their low development cost, short development cycle, and the widespread availability of COTS subsystems. Budget-conscious spacecraft designers are working to expand the range of missions that can be accomplished with nanosatellites, and a key area of development fueling this expansion is the creation of micropropulsion systems. One such system, originally developed at the Australian National University (ANU), is an electrothermal plasma thruster known as Pocket Rocket (PR). This device heats neutral propellant gas by exposing it to a Capacitively Coupled Plasma (CCP), then …

Interplanetary Transfer Trajectories Using The Invariant Manifolds Of Halo Orbits, Megan S. Rund

Master's Theses

Throughout the history of interplanetary space travel, the Newtonian dynamics of the two-body problem have been used to design orbital trajectories to traverse the solar system. That is, that a spacecraft orbits only one large celestial body at a time. These dynamics have produced impressive interplanetary trajectories utilizing numerous gravity assists, such as those of Voyager, Cassini, Rosetta and countless others. But these missions required large amounts of delta-v for their maneuvers and therefore large amounts of fuel mass. As we desire to travel farther and more extensively in space, these two-body dynamics lead to impossibly high delta-v values, and …