Aerospace Engineering Commons^™

Silver-Based Microbial Check Valve For Spacecraft Potable Water Systems, Rogelio E. Garcia

Chemical Engineering Undergraduate Honors Theses

As human space exploration increases, the development of a more efficient potable water treatment system suited for spacecraft becomes crucial. This Waste-management Education Research Consortium (WERC) challenge was designed to explore the viability of microbial control through the utilization of silver ions as a biocide for possible integration into the Tranquility Node 3 water purification system aboard the International Space Station (ISS). Current systems using iodine risk causing hyperthyroidism from overexposure; however, silver can be safely ingested without this side effect. After researching silver delivery methods including electrochemical ion production, controlled release, or a combination of the two, our team …

Task 1: Silver-Based Microbial Check Valve For Spacecraft Potable Water Systems, Eric Beitle

Chemical Engineering Undergraduate Honors Theses

As human space exploration increases, the development of a more efficient potable water treatment system suited for spacecraft becomes crucial. This Waste-management Education Research Consortium (WERC) challenge was designed to explore the viability of microbial control through the utilization of silver ions as a biocide for possible integration into the Tranquility Node 3 water purification system aboard the International Space Station (ISS). Current systems using iodine risk causing hyperthyroidism from overexposure; however, silver can be safely ingested without this side effect. After researching silver delivery methods including electrochemical ion production, controlled release, or a combination of the two, our team …

Moore’S Law And Space Exploration: New Insights And Next Steps, Michael Howell, Venkat Kodali, Richard Segall, Hyacinthe Aboudja, Daniel Berleant

Journal of the Arkansas Academy of Science

Understanding how technology changes over time is important for industry, science, and government policy. Empirical examination of the capability of technologies across various domains reveals that they often progress at an exponential rate. In addition, mathematical models of technological development have proven successful in deepening our understanding. One area that has not been shown to demonstrate exponential trends, until recently, has been space travel.

This paper will present plots illustrating trends in the mean lifespan of satellites whose lifespans ended in a given year. Our study identifies both Wright’s law and Moore’s law regressions. For the Moore’s law regression, we …

Active Permanent Magnet Attitude Control For Cubesats Using Mu-Metal Shielding, Maxwell Martin

Mechanical Engineering Undergraduate Honors Theses

Cube-Satellites (CubeSats) are nanosatellites composed of cube shaped units, each nominally 10cm to a side and around 1kg in mass. Due to their inherent size and weight limitations, it is often impractical to use conventional attitude, or rotational, control methods such as thrusters on these small satellites. Several methods, including magnetorquer rods and small reaction wheels, are often used instead of traditional methods to work around the size and weight limitations. As a new alternative to these methods, a permanent magnet mounted on a rotatable shaft could be used to achieve attitude control. In much the same way that a …

Optimization Of Miniaturized Resonant Microwave Cavities For Use In Q-Thrusters, Joshua Steven Pennington

Graduate Theses and Dissertations

A gedankenexperiment was considered to compare a hypothetical thruster that used no reaction mass to propulsion methods currently in use. A brief discussion of previous research work done on closed resonant cavity thrust devices was conducted. Using the previous work as a template, a simulation plan was devised. Computational models of resonant microwave cavities were constructed and investigated using COMSOL software. These COMSOL simulations were verified against known analytical solutions using Matlab software as a computational tool. Multiphysics simulations were created to study the microwave heating environment of the resonant cavities. From the COMSOL study outputs, the electromagnetic field magnitude, …

Time-Of-Flight Based Sonic Speed Measurements For Cold Gas Thruster Development, Brandon W. Kempf

Mechanical Engineering Undergraduate Honors Theses

The purpose of this thesis is to explore an experiment developed for validating the usage of a gaseous solution of water and propylene glycol for cold gas propulsion. The experiment involves a “Time of Flight” method of calculating the speed of sound in the gas and the corresponding specific heat ratio using a copper tube, two MEMS microphones, a piezoelectric speaker, and data-acquisition hardware. The experiment was calibrated using the known thermodynamic properties of air. The accuracy of the experiment was found to be within 0.6% for calculations of the speed of sound in air and within 1.0% of the …

The Aerodynamic And Dynamic Loading Of A Slender Structure By An Impacting Tornado-Like Vortex: The Influence Of Relative Vortex-To-Structure Size On Structural Loading, Matthew Nicholas Strasser

Graduate Theses and Dissertations

Structural loading produced by an impacting vortex is a hazardous phenomenon that is encountered in numerous applications ranging from the destruction of residences by tornados to the chopping of tip vortices by rotors. Adequate design of structures to resist vortex-induced structural loading necessitates study of the phenomenon that control the structural loading produced by an impacting vortex. This body of work extends the current knowledge base of vortex-structure interaction by evaluating the influence of the relative vortex-to-structure size on the structural loading that the vortex produces. A computer model is utilized to directly simulate the two-dimensional impact of an impinging …

Simulation Of A Dissimilar Fresnel Relfectarray Antenna, Paul L. Rogers

Electrical Engineering Undergraduate Honors Theses

Planar reflectarray antennas behave similarly to parabolic dish antennas, but are flat in their construction. They work by having areas on the planar surface of different reflection phase, causing the signal to be reflected to a focal point. This is done today by making planar patch antennas with the required reflection phase. These antennas are typically used in aerospace. This paper specifically discusses a planar reflectarray antenna that was originally constructed in Millimeter Wave Circularly Polarized Fresnel Reflector for On-Board Radar on Rescue Helicopters by K. Mazouni. In this paper, the authors eight different shaped antennas to form the planar …

Coreless Planar Transformer Using Low-Temperature Co-Fired Ceramics For Isolated Gate Driver Applications, Matthew W. Feurtado

Electrical Engineering Undergraduate Honors Theses

The aim of this thesis project is to design a signal isolation transformer for gate driver applications using coreless planar transformers (CPT) on a low-temperature co-fired ceramic (LTCC) substrate. To achieve this goal a modulator-demodulator circuit will be selected from several existing designs and an isolation transformer will be designed as a CPT to produce a high frequency high temperature signal isolation for gate driver applications in switching converters, audio drivers, and motor drives. Several designs for coreless planar transformers will be evaluated and tested, and the results will be compared to the theoretical performance obtained from SPICE models for …

Trajectory Generation For Stair Ascent Walking Using Rayleigh Oscillator, T. Afzal, Andrew B. Wright, Kamran Iqbal

Journal of the Arkansas Academy of Science

This paper describes a trajectory generation technique for stair-ascent walking. The knee, hip and ankle joint trajectory during stair ascent are generated using mutually coupled, nonlinear oscillators. The parameters of the oscillators are tuned using the harmonic balance method, which converts the nonlinear differential equations to a set of algebraic equations. Fourier analysis of data generated by stair-ascent walking is performed to extract the amplitude and the phase of the dominant frequency components for each joint trajectory. The solution for the oscillator is assumed to be a sinusoidal wave and then by harmonic balance method the parameters of the oscillator …

Flexible Circuits For Aerospace Applications With Special Emphasis On Rf Connectors, Abhishek Nareshraj Singh

Graduate Theses and Dissertations

The current work focused on the study of flexible electronic circuits for use in aerospace applications with emphasis on RF Connectors. The electrical and mechanical performance of the flexible circuits was studied and compared to a standard coaxial cable for feasibility study in avionics space. Also, Anisotropic Conductive Films (ACF) are studied for connecting the flexible RF connectors and their performance studied for electrical and mechanical behavior with change in bonding parameters.

Design Of Orbital Maneuvers With Aeroassisted Cubesatellites, Stephanie Clark

Graduate Theses and Dissertations

Recent advances within the field of cube satellite technology has allowed for the possible development of a maneuver that utilizes a satellite's Low Earth Orbit (LEO) and increased atmospheric density to effectively use lift and drag to implement a noncoplanar orbital maneuver. Noncoplanar maneuvers typically require large quantities of propellant due to the large delta-v that is required. However, similar maneuvers using perturbing forces require little or no propellant to create the delta-v required. This research reported here studied on the effects of lift on orbital changes, those of noncoplanar types in particular, for small satellites without orbital maneuvering thrusters. …

Multiuav2 Agent Swarming For Distributed Atr Simulation, Kyle White

Computer Science and Computer Engineering Undergraduate Honors Theses

Traditional automatic target recognition (ATR) is performed by unmanned aerial vehicles (UAVs) depending on a central control tower to provide the high level organization of the system. The UAVs fly through a region of interest to identify targets and relay all communication through a central control tower. The centralized approach to ATR has limited fault-tolerance, scalability with regards to the number of UAVs, and susceptibility to malicious attacks on the central tower [2]. A swarm-driven alternative [1] is extended with a communication control scheme to address fault-tolerance and scalability while utilizing the higher onboard processing power now available for UAVs …

Pressure And Flow Validation Of A Second Generation Gas Extraction Probe For A Hybrid Rocket Gas Extraction System, Constance Meadors, Andrew B. Wright

Journal of the Arkansas Academy of Science

A gas extraction system (GES) has been designed for use with the hybrid rocket facility at the University of Arkansas at Little Rock (UALR) for spectroscopic analysis of rocket plumes. While monitoring gas flow-rate and pressure, the GES extracts gases from the hybrid rocket plume and transports them to a mass spectrometer. This paper describes design and construction of a gas extraction probe (GEP) prototype capable of extracting gases directly from the plume. Gas dynamics equations were used to design two venturi-type GEP, converging and converging-diverging. The probe was tested with air to verify design assumptions. Flow rate through the …

Radiometer For The Investigation Of Infrared Emissions From Flames And Rocket Plumes, Kathy Underhill, M. Keith Hudson, Jason Willis, Mokhtar Mofidi, Matthew J. Russo

Journal of the Arkansas Academy of Science

A prototypical radiometer using standard one inch interference filters and a lead selenide detector was constructed for use in flame and rocket plume studies. This radiometer was designed to employ a 600 Hz chopper and chopper frequency/phase reference circuit for signal processing. Bandpass filters centered for either 2.7 mum or 4.45 mum were placed in the optical path. The passed carbon dioxide or water vapor band energy irradiated the lead selenide detector, resulting in an output voltage. This signal was then fed into a dedicated synchronous detector. The signal was then recorded by a computer system equipped with an analog-to-digital …