Aerospace Engineering Commons^™

Autonomous Feature Detection For Capture Path Planning For Rendezvous And Docking With Non-Cooperative Spacecraft, Trupti Mahendrakar

Theses and Dissertations

With the increasing risk of collisions with space debris and the growing interest in on-orbit servicing, the ability to autonomously capture non-cooperative, tumbling target objects remains an unresolved challenge. This thesis provides an autonomous and artificial intelligence solution to either inspect, avoid, or perform on-orbit spacecraft servicing of an uncooperative resident space object (RSO). The solution is built on the fundamentals of Convolutional Neural Networks (CNN), which is used to classify the four most targeted features of a spacecraft essential for docking and collision avoidance during rendezvous, such as solar panels, antennas, spacecraft bodies, and thrusters. The solution was then …

Preliminary Development Of The Dialysis-Membrane-Based Passive Biocide Delivery System For Spacecraft Water Recovery Units, Rogelio Elias Garcia Fernandez

Graduate Theses and Dissertations

The purpose of this investigation is to explore the capabilities of a dialysis-membrane-based system for the in-line dosing of silver ions to treated water in spacecraft water recovery units. The spacecraft environmental control and life support system community (ECLSS) are interested in adopting silver ions as a biocide in future spacecraft water recovery processes since silver ions are effective biocide at concentrations that humans can safely consume. The system has been designed following the configuration of the Water Processor Assembly (WPA) aboard the International Space Station. In this configuration, silver ions have to be added at the last step in …

Computational Sodium Heat Pipe Simulation In Three Dimensions For Transient Nuclear Reactor Analysis With Variable Surface Heat Flux, Valerie Jean Lawdensky

UNLV Theses, Dissertations, Professional Papers, and Capstones

Heat pipes are used to transfer heat through phase change in a liquid/vapor contained in a metal tube. They are passive devices that require no pumps to circulate the fluid and can transfer heat far more efficiently than a solid copper rod of the same diameter. They are commonly used in laptop computers where copper heat pipes filled with water take heat away from the CPU and transfer the heat to air through a heat exchanger. Heat pipes were also used in the Kilopower nuclear reactor where higher temperatures required sodium as the working fluid with stainless steel tubes. Computer …

Numerical Validation Of A Cryogenic Thermo-Fluid Mixing Model, Sean William Bowman

Theses and Dissertations

Thermal management of a hot convective gaseous flow can be achieved by the injection of a cold liquid stream. This cooling effect is constrained by the amount of liquid injected, the rate of evaporation of the liquid, and the length of the domain. In this study, such a domain is referred to as a “mixer”. The mixer used to facilitate this process is designed with a venturi geometry, such that the throat of the pipe creates a drop in the static pressure of the gaseous crossflow. Liquid coolant can thereby be passively entrained from a central pipe (plenum) by the …

Helicopter Flight Energy Modeling And Scaling For Urban Air Mobility Applications, Nolan Gene Hopkins

Theses and Dissertations

The costs associated with conducting full-scale helicopter flight tests in terms of both time and money beg to question the validity of using small-scale model helicopters in order to predict full-scale performance. To do this, the energy change for a small time interval is determined throughout a full-scale helicopter’s flight of a given profile, and the overall energy use compared to model results. The profile is then scaled based on a variety of factors, and the accuracy of energy scaling compared for each. Scaling dimensions based off helicopter weight and energy reserve modeling show promising results, but comparison of relative …

Flight Test Evaluation Of Elevator Stick Force Gradients On General Aviation Aircraft, Isaac Lee Faust

Theses and Dissertations

The objective of this research is to establish a suitable method of changing elevator stick force gradients on a Piper Warrior II. After finding a range of stick force gradients, the gradients will later be evaluated to get handling qualities ratings. A stick force gradient is the change in stick force as the airspeed deviates from trim condition. An aircraft’s yoke force gives pilots haptic feedback which improves their situational awareness without the need to assess instrument readings. A high stick force gradient will give the pilots a lot of feedback but will require more physical exertion to fly the …

Experimental Study Of Progressive Crushing Behaviour In Pultruded E-Glass Tubes Using Crown Triggers And A New Perforated Trigger, Chirag Mohan Dodani

Theses and Dissertations

An experimental study is conducted on the progressive crushing behavior and the energy absorption during crushing of pultruded fiberglass tubes, initiated by two types of crush triggers, a previously tested crown trigger, and a new perforated trigger. These crush triggers are introduced at the loading end of a pultruded E-Glass/vinyl-ester, circular tube coupon. Coupons with various trigger diameters and number of holes are crushed under quasi-static compression, to evaluate the trigger effectiveness, crushing response, and energy absorption during sustained crushing. It is observed that all trigger types induced progressive crushing in the splaying mode, characterized by the formation of a …

Optimal Sizing And Control Of Hybrid Rocket Vehicles, Srija Ryakam

Doctoral Dissertations and Master's Theses

In the present work, a genetic algorithm is used to optimize a hybrid rocket engine in order to minimize the propellant required for a specific mission. In a hybrid rocket engine, the mass flow rate of the oxidizer can be throttled to enhance the performance of the rocket. First, an analysis of the internal ballistics and the ascent trajectory has been carried out for different mass flow rates of the oxidizer as a function of time, for a fixed amount of oxidizer, in order to study the effect of throttling. Two equivalent problems are considered: in the first problem the …

Airspace Integration Of New Entrants And Safety Risk Management Models, Fadjimata Issoufou Anaroua

Doctoral Dissertations and Master's Theses

In recent years, the demand for airspace access of Unmanned Aerial Systems (UAS) increased significantly and is continuously increasing for different altitude-types UAS. A similar evolution is expected from Commercial Space Operations (CSO) in the next years. These aviation/aerospace systems will need to be seamlessly integrated into the National Airspace System (NAS), at their operational altitude levels, and accounted for from all perspectives, including proactively addressing their safety hazards. This thesis captures the requirements for the new entrants’ integration, and then identifies and analyzes the safety risks added to the NAS operations by its new entrants, the future omnipresent UAS …

Trajectory Generation For A Multibody Robotic System: Modern Methods Based On Product Of Exponentials, Aryslan Malik

Doctoral Dissertations and Master's Theses

This work presents several trajectory generation algorithms for multibody robotic systems based on the Product of Exponentials (PoE) formulation, also known as screw theory. A PoE formulation is first developed to model the kinematics and dynamics of a multibody robotic manipulator (Sawyer Robot) with 7 revolute joints and an end-effector.

In the first method, an Inverse Kinematics (IK) algorithm based on the Newton-Raphson iterative method is applied to generate constrained joint-space trajectories corresponding to straight-line and curvilinear motions of the end effector in Cartesian space with finite jerk. The second approach describes Constant Screw Axis (CSA) trajectories which are generated …

Satellite Deceleration Using Gravity Assist From Asteroid, Nicolas M. Prulhiere

Doctoral Dissertations and Master's Theses

Satellites have used gravity assists to increase their speed when exploring the solar system. This same maneuver can be done but with the objective to slow down the satellites. This has been theorized to slow down asteroids using the moon to capture them in earth’s orbit. My goal is to determine if asteroids can be used to provide a change in speed great enough to the point that after multiple of these maneuvers the satellite can come to a stop. By being able to slow down and stop a satellite without having to use thrusters will allow the mass allocated …

Second-Order Reliability Methods: A Review And Comparative Study, Zhangli Hu, Rami Mansour, Mårten Olsson, Xiaoping Du

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Second-order reliability methods are commonly used for the computation of reliability, defined as the probability of satisfying an intended function in the presence of uncertainties. These methods can achieve highly accurate reliability predictions owing to a second-order approximation of the limit-state function around the Most Probable Point of failure. Although numerous formulations have been developed, the lack of full-scale comparative studies has led to a dubiety regarding the selection of a suitable method for a specific reliability analysis problem. In this study, the performance of commonly used second-order reliability methods is assessed based on the problem scale, curvatures at the …

Crashworthiness Of Metallic Tubes Under Off-Axial Loading, Victor Manuel Bautista Katsalukha

Theses and Dissertations

Energy absorbing structures (EAS) are structures used to make the frame of a vehicle absorb energy during an impact scenario and keep the deceleration forces within survivable limits for the occupant(s). These structures are found in all sorts of vehicles, such as cars, helicopters, airplanes, etc., and come in many types of shapes (circular, square, triangular tubes and flat or curved plates) and materials (metals and composites). In this thesis, 304 Stainless Steel tubes with circular and square cross-sections are investigated when subject to off-axis loading at angles at 0, 5, 15 and 25°. The square tubes had two different …

Exploration Of Simplified Vehicle Operations For Electric Vertical Takeoff And Landing Through A Garmin Autopilot On A Piper Warrior, William Stefan Dietrich

Theses and Dissertations

Urban Air Mobility is an emerging concept that would allow urban transportation of both people and cargo through the air in large metropolitan cities. Because of new propulsion methods like distributed electrical propulsion, the Urban Air Mobility is concentrating on Electric Vertical Takeoff and Landing aircraft to implement its concept. Controlling and maneuvering these aircraft are very different than piloting traditional general aviation even through Electric Vertical Take and Landing aircraft aim to be in the same size category. Because of the more complex controls needed for Electric Takeoff and Landing aircraft, Simplified Vehicle Operation schemes are being developed in …

Feasibility Analysis And Performance Study Of A Pulsed Solid Propellant Integrated Propulsion System For Small Satellites, Tahir Kanchwala

Theses and Dissertations

Solid propellant has come a long way since the 13th century when gunpowder was widely used as the go-to means in rocket propulsion. Of course, back then, rockets were not intended to carry humanity out of the atmosphere. Untill the introduction of liquid propellants in the mid-20th century, solid propellants were the foundation. Still, liquid propellants aimed to add more stability and controllability to rocketry and thus were preferred over their solid counterparts. This thesis seeks to analyze a novel type of propulsive device that aims to eliminate challenges faced by both types of fuels and instead utilize the advantages …

Small Satellite Development And Mission Design For Low Earth Orbit And Geostationary Transfer Orbit Missions, Ashiqur Rahman

Open Access Theses & Dissertations

Aerospace Center formerly known as cSETR at UTEP is a NASA funded center of excellence in aerospace and exploration, focusing on strategic capability development in propulsion and robotic lander, lunar surface exploration, and small spacecraft technologies. To support the center’s mission for space exploration and to demonstrate advancements in small satellite technologies, the Aerospace Center at The University of Texas at El Paso is on track to develop and launch several CubeSats in next few years. A CubeSat is a small satellite that has become popular in recent years due to their low cost, low complexity and short development timeline. …

Data-Driven Damage Initiation Criteria For Carbon Fiber Reinforced Polymer Composites, Alexander Richard Post

College of Computing and Digital Media Dissertations

Computational progressive failure analysis (PFA) is vital for the design, verification, and validation of carbon fiber reinforced polymer (CFRP) composites. However, the computational cost of PFA is usually high due to the complexity of the model. The damage initiation criterion is one of the essential components of a PFA code to determine the transition of a material’s state from pristine or microscopically damaged to macroscopically damaged. In this thesis, data-driven models are developed to determine the matrix damage initiation based on the Mohr-Coulomb model and Hashin model. For 2D plane stress states, the computational cost for determining damage initiation can …

Analysis Of Energy Utilization And Losses For Jet-Propelled Vehicles, Mohammad Abbas, David W. Riggins

Mechanical and Aerospace Engineering Faculty Research & Creative Works

The global control volume-based energy utilization balance for an aerospace vehicle is extended to allow for the analysis of jet-propelled vehicles. The methodology is first developed for analyzing the energy utilization and entropy generation characteristics of jet engines without airframe considerations. This methodology, when combined with separate energy utilization analysis for an unpowered airframe, allows for the assessment of a powered vehicle. Wake entropy generation for a powered vehicle is shown to be the summation of the wake entropy generation associated with the propulsion system (no airframe) and the unpowered airframe. The fundamental relationship between overall entropy generation and the …

Exploring Dft+U Parameter Space With A Bayesian Calibration Assisted By Markov Chain Monte Carlo Sampling, Pedram Tavadze, Reese Boucher, Guillermo Avendaño-Franco, Keenan X. Kocan, Sobhit Singh, Viviana Dovale-Farelo, Wilfredo Ibarra-Hernández, Matthew B. Johnson, David S. Mebane, Aldo H. Romero

Faculty & Staff Scholarship

The density-functional theory is widely used to predict the physical properties of materials. However, it usually fails for strongly correlated materials. A popular solution is to use the Hubbard correction to treat strongly correlated electronic states. Unfortunately, the values of the Hubbard U and J parameters are initially unknown, and they can vary from one material to another. In this semi-empirical study, we explore the U and J parameter space of a group of iron-based compounds to simultaneously improve the prediction of physical properties (volume, magnetic moment, and bandgap). We used a Bayesian calibration assisted by Markov chain Monte Carlo …

Graphene Flake Self-Assembly Enhancement Via Stretchable Platforms And External Mechanical Stimuli, Harrison A. Loh, Claudio Marchi, Luca Magagnin, Konstantinos A. Sierros

Faculty & Staff Scholarship

While the green production and application of 2D functional nanomaterials, such as graphene flakes, in films for stretchable and wearable technologies is a promising platform for advanced technologies, there are still challenges involved in the processing of the deposited material to improve properties such as electrical conductivity. In applications such as wearable biomedical and flexible energy devices, the widely used flexible and stretchable substrate materials are incompatible with high-temperature processing traditionally employed to improve the electrical properties, which necessitates alternative manufacturing approaches and new steps for enhancing the film functionality. We hypothesize that a mechanical stimulus, in the form of …

Investigations Of The Negative Temperature Coefficient Region Of Sustainable Aviation Fuels For Mitigation Of Global Warming, Richard C. Smith Iii

Honors College Theses

An investigation was led to determine the correlations between the durations of Ignition Delay (ID), Combustion Delay (CD), Derived Cetane Number (DCN), Negative Temperature Coefficient (NTC), Low-Temperature Heat Release (LTHR) regions, ringing intensity, and precent mass burn, and the effect of blending the Fischer-Tropsch (F-T) synthetic aerospace fuel (SAF), iso-paraffinic kerosene (IPK), with petroleum derived Jet-A aerospace fuel on these regions. Neat blends of Jet-A and IPK and three by mass blends of the fuels will be researched. These blends include mass percentages of 75%Jet-A and 25%IPK (75Jet-A25IPK), 50%Jet-A 50%IPK (50Jet-A50IPK), and 25%Jet-A 75%IPK (25Jet-A75IPK). The study will utilize a …

Fatigue Damage Quantification And Life Estimation With Provision For Microstructure, Arash Pourbagheri Jirandehi

LSU Doctoral Dissertations

This dissertation provides methodologies for the quantification of different forms of fatigue damage by considering the role of microstructure. The laws of thermodynamics in conjunction with Finite Element Method (FEM) are utilized to devise thermodynamically-base frameworks for the estimation of cyclic damage in polycrystalline metals. Accordingly, a microstructure-sensitive platform for fatigue life estimation is introduced. The proposed framework is assessed for 3D printed metallic alloys at room and elevated temperatures. Further, it is used to analyze the fatigue performance difference between additively manufactured Inconel 718 in three print orientations. This research is of fundamental vital interest because it ensures that …

Issue 18: Contributors, Don Flournoy

Online Journal of Space Communication

List of Issue 18 Contributors

Sunsat Design Competition 2015-2016 First Place Winner – Team Space Transport: Power Satellites Beamed Energy Bootstrapping, Keith Henson, Anna Nesterova

Online Journal of Space Communication

This International SunSat Design Competition first-place winner for 2016 describes a beamed energy transport system that will operate in Space above low earth orbit (LEO) as a way to move power satellite parts into high orbits.

This design, entitled “Beamed Energy Bootstrapping,” makes use of small propulsion power satellites to provide the energy for space-based vehicles using electric arcjets. The proposal lays out a scheme to get the first propulsion power satellite in place without damage as it passes through the orbiting space junk below 2000 km.

Click here to see the video: Space Transport for Power Satellites Beamed Energy …

Sunsat Design Competition 2015-2016 Second Place Winner – Team Pathway To Power : Wireless Power Transfer, Javier Tandazo, Ethan Wong, Curtis Waggoner, John Guggenheim, Alexander Carter

Online Journal of Space Communication

Solar Power Satellites (SPS) using Wireless Power Transfer (WPT) to beam renewable energy to consumers on earth face three grand challenges: moving parts, heat dissipation, and radio interference. Solutions to each of these “show stoppers” are presented here. Further, a progressively more-complex pathway is described which starts where we are now and leads step-wise to implementation of large-scale Space Solar Power (SSP).

The first two grand challenges are addressed by a novel SPS design based on a thin-walled cylinder configuration of solar panels. The remaining challenge is tackled through a newly-discovered antenna configuration which allows dramatic reduction in radio/telecom interference …

Sunsat Design Competition 2014-2015 Third Place Winner – Team Martian: Space Solar Power Test Bed, Jeremy Straub, Tristan Plante, Benjamin Kading, Alex Holland, Landon Klein, Jordan Forbord

Online Journal of Space Communication

We propose a four-stage plan to demonstrate the effectiveness and safety of Space Solar Power (SSP) for use on Earth. Our project goal is to achieve Technology Readiness Level (TRL) by means of: 1) a test mission in low Earth orbit using a small spacecraft; 2) that will support a manned mission to Mars; 3) that includes a bent pipe experiment (power supplied from Earth, to a spacecraft and back to Earth), and 4) to complete system deployment.

The primary impediment to SSP implementation is thought to be the acceptance of the system by those on Earth who may be …

Sunsat Design Competition 2014-2015 First Place Winner – Team Cast: Multi-Rotary Joints Sps, Xinbin Hou, Meng Li, Lili Niu, Lu Zhou, Ying Chen, Zhengai Cheng, Haipeng Ji

Online Journal of Space Communication

Space Power Satellite (SPS) is a huge spacecraft designed to collect solar energy in space for supplying electric power to the electric grid on the ground. The SPS concept was first proposed by Dr. Peter Glaser in 1968.

Various studies on SPS in various countries have been produced over the past forty years. Today, there are multiple variations on this early concept, both in innovation and in optimization. Because of the huge size, immense mass and high power of these SPS installations, there are many technological difficulties.

Here, a new Multi-Rotary Joints SPS (MR-SPS) concept is proposed. The large solar …

Sunsat Design Competition 2014-2015 Second Place Winner – Team Sunflower: Thermal Power Satellite, Keith Henson, Steve Nixon, Kris Holland, Anna Nesterova

Online Journal of Space Communication

Space-based Solar Power has failed to be competitive on cost in spite of decades of study. A new approach appears to resolve the cost issue, undercutting coal and opening huge markets for low cost solar power from space. There are two parts to the problem. First is the cost of lifting parts to Geosynchronous Earth Orbit (GEO; second is the mass of parts that make up a power satellite.

Our team is proposing a combination that makes use of Skylon to Low Earth Orbit (LEO), and a 15,000 ton payload ground powered electric propulsion from LEO to GEO. This strategy …

Sunsat Design Competition 2013-2014 Third Place Winner – Team University Of North Dakota: Nano Ssp Satellite, Corey Bergsrud, Robert Bernaciak, Ben Kading, John Mcclure, Jeremy Straub, Subin Shahukhal, Karl Williams

Online Journal of Space Communication

This work presents the conceptualization of a Space-to-Space Microwave Wireless Power Transmission (S2S-MWPT) experimental demonstration mission using small spacecraft. Literature reviews [1, 2] suggest a stepwise procedure for technology demonstrations in support of advancing space solar power satellite (SSPS) systems. These technologies should be verified first on Earth and then in-space using small satellites. This project built its S2S-MWPT demonstration concept within the University NanoSat program restrictions (dimensions of 50cm x 50cm x 60cm and mass of 50kg). The idea is to use these upper limit restrictions to develop the MWPT spacecraft (MicroSat). Contained inside the MicroSat …

Sunsat Design Competition 2013-2014 Second Place Winner – Team Solar Maximum Llc: Sun-Synchronous Orbits, Danny R. Jones, Anna Nesterova

Online Journal of Space Communication

The orbital location of PowerSats plays a critical role in determining the mass of the solar power satellite (PowerSat) transmitter and the size of the rectenna on the Earth’s surface. These in turn play an important role in the cost of deploying the PowerSat, especially the cost of launching the PowerSat into orbit as the transmitter makes up a large part of the PowerSats mass. We will consider a new approach to PowerSat orbital positioning by considering a circular sun-synchronous orbit at 5,185.3 kilometers with an inclination of 142.1 degrees. Locating the PowerSat at this location offers several benefits and …