Aerospace Engineering Commons^™

System Integration And Validation Of The Cal Poly Spacecraft Attitude Dynamics Simulator Mk. Iv, Bricen S. Rigby

Master's Theses

The Cal Poly Spacecraft Attitude Dynamics Simulator (SADS) is an ongoing project that seeks to enable the simulation and validation of sensors, actuators, and control logic related to spacecraft attitude control. The SADS platform rests atop a spher- ical air-bearing device which allows for nearly frictionless rotation in all three axes. The orientation of the platform is controlled by four reaction wheels arranged in a pyramidal configuration. Over the past few years, there have been significant updates to the reaction wheel subsystem, as well as requests for a more capable central com- puter. Therefore, a new system architecture for the …

Optimization Of Repeat Ground Track Constellation Design For Complex Discontinuous Regional Coverage, Paige Jewell

Master's Theses

The continued growth of low Earth orbit (LEO) satellite constellations motivates efficient constellation design methods to reduce cost and complexity. Although brute-force methods are commonly employed in the preliminary design of satellite constellations, pairing analytic methods with optimization algorithms provides a more efficient means of searching the design space. Constellation design for continuous global and regional coverage is well-established; however, strategies for discontinuous regional coverage remain underdeveloped. This thesis focuses on an analytic geometry-based method for computing satellite coverage and revisit metrics, coupled with genetic algorithm optimization to efficiently explore the design space. The viability of this method is shown …

Effects Of Atomic Oxygen Exposure On Stressed Drag Sail Materials For Low Earth Orbit Applications, Nazanin Sadeghian Dezaki

Master's Theses

As low Earth orbit (LEO) has become an increasingly valuable region for satellite operations, it has grown increasingly congested. The Federal Communications Commission (FCC) deorbit regulations require satellites to be deorbited within 5 years of launch, and drag sails represent a practical means of meeting this requirement. An important consideration for drag sail design is the effect of atomic oxygen (AO) on sail materials. To address the gap in the literature regarding the behavior of stressed drag sail materials under AO exposure, a new test plate was manufactured for the California Polytechnic State University minimum atmospheric experimentation (MAX) AO chamber. …

Development Of A Computer Vision Based Rendezvous And Docking Test Platform, David T. Forbes

Master's Theses

This thesis presents the work completed in the development and testing of a low-cost modular sensor package capable of rendezvous and docking by providing a vehicle with relative navigational commands. These navigational commands are created using relative localization data gathered and processed onboard the sensor package, with validation, in post-processing, against global localization data. This research aims to reduce the cost of smaller autonomous vehicles by removing the need for custom control units, as its modular nature will allow it to be adapted to many different systems and vehicles. Discussed within this thesis is the rapid prototyping, development, and testing …

Spaceotter: A Floating Spacecraft Simulator Air Bearing Vehicle For Hardware-In-The-Loop Experiments And Research, Alexander Debartolo

Master's Theses

Growing interest in nanosatellites has increased demand for accessible ground-testing methods, which have historically been expensive and restricted. Floating Spacecraft Simulators (FSS), built around Air Bearing Vehicles (ABVs), address this gap by approximating a zero-gravity, friction-minimized environment suitable for testing spacecraft control systems, robotics, and propulsion on the ground.

This thesis presents the design, realization, and initial performance characterization of the Space Optically Tracked Testbed for Experiments and Research (SpaceOTTER) ABV, developed for the Cal Poly Space Robotics Lab. SpaceOTTER is the first step toward emulating the 3 degree of freedom (3-DOF) planar dynamics of a simulated spacecraft and is …

Hamster: Hybrid-Actuated Mobile Spherical Terrain Exploration Rover, Winnie Gao

Master's Theses

The expansion of space exploration to increasingly challenging planetary environments requires mobility systems capable of extreme traversal capabilities and operational reliability. This thesis presents the design, development, and testing of a low-cost Hybrid-Actuated Mobile Spherical Terrain Exploration Rover (HAMSTER) intended for use on a planetary surface exploration mission. HAMSTER uses a pendulum-based actuation method for steering and an actuated internal shaft to propel the vehicle forward. The internal structure includes a two-tiered central case composed of the navigation control module, accelerometer, motor controller, primary DC motor, battery, voltage regulators, Raspberry Pi, pendulum servo motor, and drive shafts. Additive manufacturing through …

Design And Implementation Of An Embedded Control System For The Cal Poly Spacecraft Attitude Dynamics Simulator, Neil Mahesh Bedagkar

Master's Theses

This thesis presents the development of a cascaded reaction wheel control system for Cal Poly's Spacecraft Attitude Dynamics Simulator. This work considers system architecture, empirical modeling, high-fidelity simulation, embedded firmware, hardware integration, and experimental characterization. In discrete-time simulation, it is shown that nonlinear direct model reference adaptive control (NDMRAC) enables a nonlinear, partially known plant with realistic actuator dynamics to track the response of a canonical second-order transfer function, with settling time within 4.67% and percent overshoot within order of magnitude of the second-order response. In hardware, the feasibility of a cascaded reaction wheel control architecture is experimentally demonstrated, achieving …

Design And Development Of A Resonance Ignition System Using Gaseous Propellants, Benjamin J. Hoefer

Master's Theses

This work presents the development and experimental evaluation of a resonance igniter (RI) operating with premixed gaseous propellants. Resonance ignition is a non-electrical ignition concept in which an underexpanded jet impinges on a closed-end Hartmann–Sprenger tube (HST), generating cyclic compression and expansion waves that rapidly heat gas near the tube endwall. A modular experimental system was designed and built to investigate resonance ignition using methane–air and methane–oxygen mixtures. The system includes a supplemental configuration that may probe for mixture conditions favorable to ignition, informing RI testing. Pressure and temperature measurements were used to characterize pressure control, mixture pressure ratio (MPR), …

Improving The Reliability And Performance Of A Supersonic Indraft Tube Wind Tunnel, Christian J. Kaml

Master's Theses

Access to supersonic testing is increasing in demand, and wind tunnels remain one of the safest and most cost-effective methods for gathering high-speed flow data. Despite being more economical than alternative options, supersonic wind tunnel facilities often require substantial investment to construct, operate, and maintain.

The novel indraft tube tunnel architecture was conceived as a high-speed flow testbed that incorporates features of both Ludwieg tubes and indraft wind tunnels to maintain costs low enough to be accessible even to small universities. This design was first developed and tested in 2018 at California Polytechnic State University, featuring a cost per test …

Design And Analysis Of A Customizable 6-Dof Force/Torque Sensor, Pyeongkang Kim

Master's Theses

This thesis presents the design, development, calibration, and testing of a novel customizable six-degree-of-freedom force/torque sensor, called the Kustom Force/Torque Sensor (KFTS), for use in the Cal Poly Low Speed Wind Tunnel (LSWT). The KFTS was developed as an alternative to commercial multi-axis force/torque sensors that feature fixed specifications. The swappable components and configurable structure of the KFTS enables changes to the sensor sensitivity, sensing range, and frequency response. Experimental testing verified that the sensor behaved as a linear time-invariant system, enabling calibration through the method of least squares and allowing the applied forces and moments to be reconstructed as …

A2s Uplink Latency Minimization For Wildfire Monitoring Systems Using Mbse And Stochastic Modeling, Luis Giovanni Wang

Master's Theses

Wildfire response depends on how quickly a detection reaches the people who act on it, and the slowest remaining step is often the link that carries an alert from a remote sensing platform to a satellite. This thesis models the latency of that link, the Air-to-Space uplink, for a wildfire-monitoring UAV that carries a Starlink terminal and sends an ALERT packet to a serving Low Earth Orbit satellite. The uplink is difficult to predict because both the UAV and the satellite move, and because the wildfire environment degrades the channel at the moment the data matters most.

The thesis uses …

Aerodynamic Design And Structural Evaluation Of A Global Minimum Torque Inspired Multirotor Propeller, Zeke Bukovansky

Master's Theses

This thesis develops a repeatable design, CAD, aerodynamic postprocessing, structural screening, and manufacturing feasibility workflow for a 22-inch global minimum torque inspired multirotor propeller. Matched MIL and GMT geometries were compared at a 35 N, 4000 rpm static-hover operating condition using BEMT/XFOIL aerodynamic postprocessing, with diameter, blade count, chord distribution, airfoil schedule, and target thrust held constant. The final modeled comparison predicted a modest 1.5% reduction in torque and shaft power for the GMT case while maintaining the same thrust target. CAD construction, MATLAB reduced-order beam model, Abaqus screening, and manufacturing planning were used to identify geometry level structural and …

Development And Verification Of An Updated Thermal Model For Cal Poly's Small Thermal Vacuum Chamber, Bryce G. Leonard

Master's Theses

This thesis discusses modifications made to the Small Thermal Vacuum (TVAC) Chamber in the Space Environments Laboratory at California Polytechnic State University, San Luis Obispo, and the development and verification of an updated thermal model reflecting these changes. The chamber was redesigned to improve thermal performance, featuring a homogeneous aluminum platen coated with Aeroglaze Z306 to enhance radiative heat transfer, along with expanded data acquisition capabilities for temperature and pressure measurements.

A new thermal model of the chamber was developed in SolidWorks using a finite element approach. The model incorporates conductive and radiative heat transfer mechanisms and is configured to …

Development Of A Free-Floating Space Robotic Simulator, Truman: Terrestrial Robotic Unit For Multibody Analysis And Navigation, Jackson W. Cordova

Master's Theses

This work describes the development of a 3 Degree-of-Freedom (DOF) robotic manipulator for use on a free-floating planar air-bearing vehicle. The system developed aims to serve as a foundation for future space robotics research at the California Polytechnic State University (Cal Poly)’s Space Robotics Laboratory. Systems doc- umentation describes conceptual operation and architecture of the proposed system: Terrestrial Robotic Unit for Multibody Analysis and Navigation (TRUMAN). The key operation of TRUMAN is to study a self launch maneuver of a free-floating ve- hicle including 4 distinct phases: launch off a fixed rail, coast, reorientation using manipulator motion, and capture of …

Short Arc Angles-Only Initial Orbit Determination For Reliable Reacquisition Of Low Earth Orbit Objects, Isabella Rackemann

Master's Theses

Low Earth orbit (LEO) is becoming increasingly congested, furthering the need for accurate tracking and catalog maintenance. Initial orbit determination (IOD) is the first step in this process, providing a preliminary estimate of an object’s state given observations. When it comes to LEO optical observations, a large portion of them are inherently short in duration. Angles-only IOD methods struggle with this data, often producing highly inaccurate solutions that limit reacquisition capabilities. This study expands on prior short arc IOD research, testing seven classical and assumed circular orbit (ACO)-modified angles-only IOD algorithms on real LEO observational data spanning 0-4 degrees of …

Effects Of Atmospheric Drag On Angles-Only Initial Relative Orbit Determination Accuracy In Low Earth Orbit, Sydney Walsh

Master's Theses

Growing congestion in low Earth orbit is increasing the demand for effective space situational awareness, straining ground station capabilities. Space-based relative orbit determination offers an alternative, using line-of-sight angle measurements from a chaser spacecraft to estimate a target spacecraft's orbit. This research focuses on angles-only initial relative orbit determination (IROD), where no prior target state knowledge is assumed. It investigates how IROD solution accuracy is affected by differential atmospheric drag between the chaser and target spacecraft. A nonlinear batch least squares filter is designed to estimate the target's initial state, which is compared against a truth solution. It was found …

A Higher Order Panel Method With Vortex Particle Wake, Luca Flick-Kaiser

Master's Theses

Panel codes were some of the earliest methods for computing the flow around aircraft. Despite the availability of higher fidelity CFD methods, panel methods remain an essential tool for the development of modern aircraft, allowing engineers to quickly iterate during the conceptual design phase.

This work develops and implements a high order panel method using Python. The wake is modeled using vortex particles, resulting in an accurate wake representation with minimal user input. The integration of the higher order singularity distributions has been extended to include the calculation of the velocity gradients necessary for the vortex particle implementation. The use …

A Polygon Approach For Satellite Coverage Computation Problems, Caleb I. Arbreton

Master's Theses

During celestial body observation mission planning, predicted sensor coverage is a key analysis tool used by designers to inform concept of operations. It enables trade studies by applying a metric to assess how well different sensor, satellite, and constellation configurations can observe a mission's region of interest. The effectiveness of the studied components is then paramount in determining whether they are justified in the system architecture. Coverage computation becomes more difficult as sensor types and regions of interest (RoIs) deviate from simple shapes, and as problem formulations seek higher-fidelity results. These simplifications include: conical camera sensors, RoIs represented as simple, …

A Scalable Iteration Of The Horizon Simulation Framework Using Multithreading Techniques, Jason E. Beals

Master's Theses

The Horizon Simulation Framework (HSF) occupies a unique space in the modern aerospace modeling landscape, enabling flexible, modular modeling of mission-level agent behavior through an object-oriented, hierarchical design. HSF's hallmark breadth-first search scheduling algorithm explores a "multiverse" of possible mission execution pathways, enabling exhaustive evaluation of schedule combinations against user-defined heuristics.

As aerospace systems become increasingly complex, HSF faces critical challenges in establishing verifiable, deterministic behavior. The framework's core scheduling algorithm had not undergone systematic validation, leaving questions about temporal consistency, state management correctness, and reproducibility across different program executions. Furthermore, the exponential growth of schedule combinations creates computational bottlenecks …

Reverse Design Of Solid Rocket Grain Geometry, Yechan Kang

Master's Theses

The reverse design of solid rocket motors remains a challenging process due to the nonlinear relationship between the grain geometry and the internal ballistics. The reverse design process involves obtaining an optimal grain geometry given a target performance curve set by mission requirements, which is the inverse problem of the forward design. The purpose of this study is to assess the validity and implementation of neural network and simulated annealing algorithms to perform the reverse design process. A modified phase field model of the eikonal equation is derived to simulate the evolution of combustion surfaces over time, enabling burn back …

Development And Test Of An Automatic Mass Balancing System For Cal Poly's Spacecraft Attitude Dynamics Simulator, Cameron B. Zorio

Master's Theses

The Cal Poly Spacecraft Attitude Dynamics Simulator (SADS) is an ongoing project to develop an air-bearing platform capable of recreating on-orbit rotational dynamics with near frictionless and torque-free rotations. However, any offset between the platform's center of rotation and its center of mass will introduce a torque due to gravity.

This thesis presents the design, implementation, and experimental evaluation of a low-cost, automatic mass balancing system for the SADS to address this challenge. A new modular sliding mass system was developed that overcomes issues faced in previous iterations of the SADS, providing real-time positional control of the masses and a …

Short-Arc Angles-Only Initial Orbit Determination For Leo And Geo Objects Using A Genetic Algorithm, Joseph R. Piini

Master's Theses

An ever-growing interest in utilizing space for scientific, commercial, and defense applications has led to an exponential rise in orbital debris recent years. With this sharp increase in space objects comes a greatly increased risk of potential collisions, necessitating an increase in Space Situational Awareness. In order to best mitigate the risk of future collisions in an increasingly congested space environment, it is crucial to be able to accurately determine the orbits of these new objects for trajectory tracking. This process is initial orbit determination (IOD), and is especially difficult when only observation angles are available for short observation times. …

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 …

Cislunar Orbital Debris Removal Feasibility Analysis Using Nrho To Dro Transfers At Varying Solar Angles, Peter C. Lie

Master's Theses

The resurgence of lunar exploration necessitates the expansion of space situational awareness into cislunar space. The current tracking technologies for cislunar objects are insufficient to determine vacant orbital regimes for human spaceflight. Orbital debris generated in the cislunar environment often evolves along complex and chaotic trajectories due to the influence of multi-body dynamics. Current research into methods of removing orbital debris from space is limited to debris in Earth orbits. For cislunar orbits, debris disposal options are slowly gaining research, mostly centered on hypothetical solutions for active missions. Lunar impact and escape to heliocentric space are low-cost options, but serve …

Investigation Into Silicone-Silicate Conversion Due To Atomic Oxygen In The Low Earth Orbit Environment, Justin T. Self

Master's Theses

Silicones have been widely used over the years in spacecraft for a variety of functions, but atomic oxygen (AO) exposure in Low Earth Orbit causes a silicate (SiO₂) surface layer to rapidly develop on the silicone which results in a permanent change in its thermal and optical properties. Although this silicone to silicate conversion is known to occur, statistical predictions of layer formation as a function of time on orbit are not found in literature. This thesis utilized optical and scanning electron microscopy, Fourier-Transform Infrared Spectroscopy, diffuse reflectance spectroscopy, and nonlinear regression statistical techniques after RF plasma asher …

A Feasibility Study On Series Hybrid-Electric Propulsion For Narrow-Body Transport Aircraft, Carver J. Glomb

Master's Theses

As global climate change accelerates, the reduction of carbon emissions has become a critical objective across multiple industries. The aviation sector, however, has lagged behind other transportation domains in implementing sustainable alternatives, despite growing demand for air travel. Recent research and emerging technologies have proposed several decarbonization pathways, including hydrogen fuel, sustainable aviation fuels (SAFs), and hybrid or fully electric propulsion systems. Among these, series hybrid-electric propulsion has received comparatively limited attention, particularly for application in transport-class aircraft. This study investigates the feasibility and emissions-reduction potential of a series hybrid-electric propulsion architecture applied to a representative narrow-body platform. A Python-based …

Enhancement Of A Python Integral Boundary Layer Method, Jeffrey T. Azuma

Master's Theses

This thesis presents a series of additions to a Python based integral boundary layer software library known as PyBL. This library provides the user the means to calculate boundary layer properties using different models for boundary layer behavior. The additions feature the integration of a set of new laminar and turbulent integral boundary layer models originally developed for and currently found in the program XFOIL. These models were modified to fit the ODE solver method at the foundation of PyBL. A new method for PyBL that stitches a laminar and turbulent solution together has been developed to improve the ability …

Design And Development Of A Laboratory Star Tracker System, Kevin D. Iverson

Master's Theses

This thesis presents the design, calibration, and validation of a low-cost star tracker system and hardware-in-the-loop testbed intended for small satellite applications. The system is composed entirely of commercial off-the-shelf components and integrates both a custom star tracker and a screen-based star field simulator for controlled, repeatable testing. An analytical modeling approach was used in the early design phase to predict system accuracy based on key optical and geometric parameters, informing the selection and configuration of components and guiding the development of calibration routines.

A simulation environment was developed to validate the star tracker software and assess the impact of …

Thermally Perfect Augmentation Of A Supersonic Inlet Design Tool That Uses Method Of Characteristics, Mario V. Guardado

Master's Theses

This work is the first in a series to augment a supersonic air inlet design tool based in Python 3 to incorporate new models that increase the range of applicability of the tool. This effort focuses on improving the thermodynamics model by incorporating a thermally perfect gas model. This tool utilizes method of characteristics to solve the governing equations for an inviscid, irrotational, isentropic, steady, supersonic flow field. Multiple test cases are used to assess the accuracy of all new models. A comparison is made between the original code’s test case for a supersonic inlet at low temperatures to verify …

Development Of A Novel Bio-Mimetic Ornithopter With Variable Flapping Angle, Geourg Kivijian

Master's Theses

From the beginnings of flight, flapping-winged flight has been a goal of many engineers to mimic and replicate. With gains in aerodynamic efficiency of flight and certain other favorable characteristics such as reduced noise, higher maneuverability, and surveillance opportunities in urban environments, flapping-wing aerial vehicle(FWAV) designs are consistently pursued in many corners of academia and industry. This thesis goes into the development of a flapping wing aerial vehicle with a Bio-mimetic novel drive mechanism that is cable-driven and can produce variable amplitude and frequency flapping stroke. Employing a Field-Oriented Control (FOC) Brushless Direct Current (BLDC) motor, paired with a bio-mimetic …