Aerospace Engineering Commons^™

Celis: Compact Eyesafe Lidar System, A Portable 1.5 Μm Elastic Lidar System For Rapid Aerosol Concentration Measurement: Part 2, Retrieval Of Particulate Matter Concentration, Kori D. Moore, Alan W. Bird, Michael D. Wojcik, Robert Lemon, Jerry L. Hatfield

Space Dynamics Laboratory Publications

SDL Poster on the CELiS Compact Eyesafe Lidar System

A Novel, Direct Matrix Solver For Supersonic Boundary Element Method Systems, Cory D. Goates, Doug Hunsaker

Mechanical and Aerospace Engineering Faculty Publications

For problems with very fine surface meshes, typically the most time-consuming step of a boundary element method (BEM, also called a panel method) is solving the final linear system of equations. Many have already studied how to efficiently solve the dense, asymmetric systems which arise in elliptic BEMs. However, this has not been studied for a supersonic aerodynamic BEM, for which the governing PDE is hyperbolic. Due to this hyperbolic character, the matrix equation which arises from a supersonic BEM has a large number of identically zero elements. But the resulting linear system of equations is also not sparse in …

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, …

Finite-Time Control Strategies For Rendezvous And Proximity Operations, John Tamotsu Akagi

All Graduate Theses and Dissertations, Fall 2023 to Present

One common metric to use when designing a controller is the time that the system will take to reach the desired state. Unfortunately, many approaches to developing controllers only guarantee that the system will approach, but not exactly reach, the desired state. This can become a limitation in time-sensitive situations where rapid and complete convergence is necessary. One group of control methods, known as finite-time control, does guarantee both faster convergence and that the desired state will be reached, but often fails to define exactly what time that will occur, how much control will be used to get there, and …

A Relaxable Vortex Wake Model For Modern Supersonic Panel Methods, Joshua J. Hurwitz

All Graduate Theses and Dissertations, Fall 2023 to Present

This thesis presents an improved vortex wake model for unstructured, supersonic panel methods. Panel methods are numerical methods that utilize inviscid flow assumptions and other simplifications to allow efficient computation of pressure distributions, velocity fields, and aerodynamic forces. They are commonly used for preliminary design, automatic design codes, and automatic optimization routines. Most existing supersonic panel methods do not include automatic wake generation and relaxation. This prevents the accurate analysis of many geometries, including those with conventional horizontal stabilizers or canards. This thesis first outlines the derivation of a relaxable generalized supersonic vortex filament equation. Next, it explores other necessary …

Quasi-Static Indentation Characteristics Of Foam-Filled Sandwich Composite Structures With Additively Manufactured Cfrp And Gfrp Corrugated Cores, S.Z.H. Shah, Juhyeong Lee, Khurram Altaf, M. Mohammad, M.Z. Hussain, R.S. Choudhry

Mechanical and Aerospace Engineering Faculty Publications

This paper presents an experimental investigation on the quasi-static indentation performance of polyurethane (PU) foam-filled carbon fibre-reinforced polymer (CFRP) and glass fibre-reinforced polymer (GFRP) corrugated sandwich composite structures (SCSs) under different indenter tip geometries (conical, trapezoidal, hemispherical, pyramidal, and cylindrical shapes). The SCSs were produced using hybrid manufacturing methods: (1) the facesheets were fabricated using the vacuum-assisted resin infusion (VARI) process, (2) the CFRP and GFRP corrugated cores were additively manufactured using the fused filament fabrication (FFF) process, and (3) the self-expanding PU foam-filled the open spaces in the core. The results elucidated that the indenter tip geometry and core …

A Probabilistic Kp And Hp Driven Auroral Boundary Model Using 28 Years Of Dmsp Data, Riley N. Troyer, Russell Landry, Michael David, Vincent Eccles, Adrian E. Acosta

Space Dynamics Laboratory Publications

This paper uses energy flux data from the DMSP F6 thru F19 satellites to construct a new equatorward auroral boundary model. This method of processing the data allows one to easily extend boundary detections to different instrument generations because it is based on a standard deviation value instead of hard thresholds. Using this method, the paper provides statistics from just under 1 million auroral boundaries between 1986 and 2014. These statistics are based on normal distribution fits for each Kp/Hp and MLT bin, which allows one to specify the boundary for an arbitrary distribution percentile. The paper compares …

Thermal Straps: Aluminum 1235 Foil Qualification Summary, Holly Mortensen

Space Dynamics Laboratory Publications

Space Dynamics Laboratory (SDL) first developed thermal strap technology in 1994 when we designed, built, and tested the SABER instrument, which is still on orbit and has performed flawlessly since 2001. Since then, we have continued to pioneer solderless flexible thermal straps and supporting technologies.

SDL’s heritage thermal straps used aluminum 1145 foil, an extremely pure alloy that contains 99.45% aluminum content. Unfortunately, it is no longer readily procurable in the market. Aluminum 1235 is a very similar alloy with similar chemical composition and physical attributes, but more readily available than 1145.

This report documents the process and results in …

Development And Testing Of A Fast-Acting, 8-Bit, Digital Throttle For Hybrid Rocket Motors, Stephen A. Whitmore

Mechanical and Aerospace Engineering Faculty Publications

The potential for throttle control of hybrid rocket systems has long been known as a potential advantage for a variety of applications. Because only a single flow path is controlled, theoretically, hybrids should be significantly easier to throttle than bipropellant systems. Unfortunately, the slow response times and nonlinearity of traditional position-control valves have limited practical applications of hybrid throttling. This paper presents an alternative throttling system where the oxidizer flow path is broken into multiple streams, with each flow path controlled by a solenoid-operated on/off valve. The parallel paths allow significantly faster and more precise control than can be achieved …

Sunrise Propulsion Subsystem Leak Rate Measurement Methodology, Alex Kirkman, Brittany Woytko, Holly Walen, Bret Maughan

Space Dynamics Laboratory Publications

As part of the integration and testing for Sun Radio Interferometer Space Experiment (SunRISE), it was necessary to characterize the propellent leak rate of the fully assembled propulsion subsystem for each satellite to ensure compliance with performance requirements. SunRISE utilized a cold gas system for its propulsion subsystem, using R-236fa propellant inside a tank made from a monolithic 3D printed SLA material. It was not possible to accurately characterize the propellent leak rate via weight by measuring the mass loss from the tank. This is due to the SLA material having both a high absorbance rate of water in normal …

Multiscale Analysis Of Thermal Barrier Coated Cfrp Composites Under Thermal Loading, Devin Nielsen, Trenton M. Ricks, Juhyeong Lee

Mechanical and Aerospace Engineering Student Publications and Presentations

Carbon-fiber reinforced polymer (CFRP) composites are commonly used in high performance applications. Although offering several advantages (i.e., superior specific properties and improved structural rigidity), traditional CFRP composites often exhibit poor thermal stability due to a low matrix thermal decomposition temperature. The effective operating temperature of the CFRP composites can be raised by applying an outermost, protective thermal barrier coating (TBC) layer. Prefabricated high void content ceramic TBCs are ideal for composite applications due to their high thermal stability and relatively low thermal conductivity. In this paper, the thermo-mechanical response of the TBCCFRP composite laminate subjected to 500°C are assessed through …

Origami And Kirigami-Inspired Sandwich Panels For Uam Primary Structural Applications, Kalyan Raj Kota, Juhyeong Lee

Mechanical and Aerospace Engineering Faculty Publications

Foldcore sandwich panels (FSPs) provide highly tailorable structural and multifunctional performance over legacy sandwich panels made with honeycomb or foam cores. In FSP manufacturing, skins and foldcore are made from any flat sheets of unitary or hybrid materials, folded into a desired pattern. Two common folding mechanisms include origami and kirigami: origami core is involved with folding only, while kirigami core is associated with a strategic combination of folding and cutting. Material and core geometry can be determined to satisfy the applications’ performance requirements. Overall, origami- or kirigami-inspired FSPs have the potential to revolutionize the ways to design and …

Wing-Shaped Leading-Edge Stealth Composites Using An Over-Expanded Honeycomb Core And A Periodic Pattern Etched On Ni-Coated Glass Fabric For Lightning Strike Protection, Seonghaeng Heo, Hannah Jang, Shanigaram Mallesh, Dongjun Hong, Byeongsu Kwak, Juhyeong Lee, Youngwoo Nam

Mechanical and Aerospace Engineering Faculty Publications

This paper proposes an RF-stealth sandwich composite, designed in a leading-edge shape, using Ni-coated glass fabric and an over-expanded honeycomb core, which incorporates a highly conductive nickel-coated glass fabric for lightning strike protection. The presented structure was designed and fabricated using nickel-coated glass fiber, which effectively absorbs electromagnetic (EM) waves, and an SWCNT-coated over-expanded honeycomb core, which improves sheet resistance properties. The designed RAS was subjected to an artificial lightning strike with the waveform of component A. Pristine and damaged RAS specimens from the artificial lightning strikes were measured using a free-space measurement system. The fabricated RAS specimens demonstrated satisfactory …

Atmospheric Waves Experiment (Awe) Advanced Mesopheric Temperature Mapper (Amtm) Optomechanical Design, Fabrication, And Environmental Test, Tyrel C. Rupp, James Champagne, Greg Hopkins, Roy Esplin, Burt Lamborn, Erik Syrstad, Jordan Jacobson

Space Dynamics Laboratory Publications

The AWE AMTM is a widefield of view (WFOV) infrared imaging radiometer designed for use in measuring the P₁(2) and P₁(4) emission lines of the earth’s OH layer to determine temperature and produce images of gravity waves. The sensor was designed, built, and characterized by Utah State University (USU) Space Dynamics Laboratory (SDL) and has been externally mounted to the International Space Station (ISS) looking nadir to collect images for analysis for a minimum of two years. The Opto-Mechanical Assembly (OMA) consists of four identical imaging telescopes, each comprised of a fisheye lens, a field lens, …

Overcoming Contamination Obstacles In Additive Manufacturing A Monolithic Propulsion Structure For The Sunrise Mission, Holly Walen, Emma Brown, Robert Fowler

Space Dynamics Laboratory Publications

The SunRISE propulsion system utilizes an additively manufactured monolithic structure containing a main tank, plenum, and six thrusters. The complex design geometry and novel manufacturing approach of this structure lends itself to several problems, primarily related to the consistent fabrication of the thruster channels. Standard cleaning methods for stereolithography printing were inadequate to meet program requirements for this structure, leading to the development of a rigorous cleaning approach and intermediate characterization of the thruster throughput during the manufacturing process. In this paper, we present the cleaning and characterization approach that lent to the successful manufacturing of the SunRISE propulsion structure.

Atmospheric Waves Experiment (Awe) Advanced Mesopheric Temperature Mapper (Amtm) Optical System Design, Alignment, And Image Quality Verification, James Champagne, Roy Esplin, Tyrel Rupp, Greg Hopkins, Burt Lamborn, Erik Syrstad, Mike Holt, Matt Ralphs

Space Dynamics Laboratory Publications

The AWE AMTM is a wide field-of-view (WFOV) infrared imaging radiometer designed for use in measuring the P₁(2) and P₁(4) emission lines of the earths OH layer. From these measurements, the atmospheric temperature is determined and finally images of gravity waves will be produced as the AWE field of view transverses the OH layer. Designed, built, and characterized by Utah State University (USU) and its Space Dynamics Laboratory (SDL), the sensor has been externally mounted to the International Space Station (ISS) looking nadir. Images will be collected and analyzed for a minimum of two years. The …

Trade-Offs In Lighting For Dic Strain Measurements In Vibration-Based Fatigue Testing, Jacob R. Rigby

All Graduate Theses and Dissertations, Fall 2023 to Present

Vibration based fatigue testing offers a fast and efficient method for determining the breaking point of a material. This method often uses a device, called a strain gage, to measure the deformation of a test sample at a single spot on the test sample. However, these strain gages often break before testing is complete. To overcome this premature break, a laser vibrometer is often used to measure the amount of movement or the speed of the test sample throughout the vibration test. The deformation measured by the strain gage is compared against the amount of movement or velocity of the …

Cislunar Optimal Robust Trajectory Design With Corrective Maneuvers, Scott J. Kelly

All Graduate Theses and Dissertations, Fall 2023 to Present

One common method for determining how to get from point A to point B is by finding the most fuel-efficient path. This is a common method for spacecraft trajectory designers also. Without any random or unexpected occurrences this path is called the deterministic optimal trajectory. Sometimes unexpected events happen that result in deviating from the most fuel-efficient path; while driving, you may encounter a detour. Naturally, we tend to return to the original fuel-efficient path and continue the journey. Similar deviations happen in space. The rocket delivering a spacecraft to orbit likely will not deliver exactly to the intended starting …

Atmospheric Waves Experiment (Awe) Thermal Control System: From Design Through On-Orbit Thermal Performance, Matthew I. Ralphs, Mike Holt

Space Dynamics Laboratory Publications

The Atmospheric Waves Experiment (AWE) will provide the first global characterization of atmospheric waves that originate in Earth’s lower atmosphere and affect space weather. The instrument has been installed on the International Space Station (ISS) ExPRESS Logistics Carrier (ELC) 1 since November 2023. The main thermal control system consists of a passive, ambient temperature, bi-directional radiator to which pyrolytic graphite sheet (PGS) thermal straps connect four independent detectors, whose temperatures are actively controlled by thermoelectric coolers (TECs). This paper discusses the thermal design, thermal model correlation efforts (both with test temperature data and flight temperature data), and how the predictions …

Raditation Test Report: Characterization Of Fairchild Imaging Cis2521 Cmos Focal Plane Array, Space Dynamics Laboratory

Space Dynamics Laboratory Publications

This report documents the results of radiation testing of Fairchild CIS2521 CMOS imaging sensor. Proton radiation measurements (both transient and total ionizing dose) were performed at the Crocker Nuclear Laboratory (CNL) of the University of California, Davis (UC Davis). Latchup characterization using Heavy Ion radiation was performed at the Texas A&M University Cyclotron Institute, Radiation Effects Facility.

Principles And Practices For Creating Inherently Resilient Smallsats Despite Constrained Resources, Lee Jasper, Tyler De Caussin

Space Dynamics Laboratory Publications

Over the past few years, small satellites have become heavily utilized for both constellations and single vehicle missions. Many organizations have learned how to be successful with these platforms however, while small, they are not simple systems and first-time creators of these systems still suffer high rates of failure. AFRL's Small Satellite Portfolio has established guiding practices/principles for satellite design that help reduce overall mission risk based upon both community and internal lessons learned. These principles help make the design technically resilient and can also help with programmatic execution. This paper will discuss the principles with some detail (such as …

Development And Testing Of An 8-Bit Digitally Throttled Hybrid Rocket Motor, Trevor W. Coombs

All Graduate Theses and Dissertations, Fall 2023 to Present

Hybrid rocket motors that use a solid fuel grain and liquid oxidizer are low-cost and safer alternatives to traditional rocket motors. Another benefit of hybrid rocket motors is that during a burn, the amount of oxidizer into the combustion chamber can be changed, this capability is called throttling. To take advantage of the throttling ability of hybrid rocket motors, a throttling valve made up of 8 individually controlled valves is designed, developed, and tested, which is documented in this thesis. The results of the testing campaign show that the 8-bit digital throttling valve technology is an effective throttling technology and …

Oxider To Fuel Ratio Shift Compensation Via Vortex Strength Control In Hybrid Rocket Motors, Max W. Francom

All Graduate Theses and Dissertations, Fall 2023 to Present

Hybrid motors have existed as a hypothetical propulsion system for decades in a wide range of upper stage rocket motors due to their simple, robust, non-toxic, and versatile nature. However, inherent to hybrids is Oxidizer to Fuel ratio (O/F) shift over time, which results in performance losses for the majority of the rocket’s lifetime. The purpose of this study is to develop a hybrid rocket motor capable of manipulating O/F at will, resulting in an engine which eliminates the undesirable effects of O/F shift. By developing and refining a numerical simulation, a novel injector system, and an open-loop control scheme, …

Development, Modeling, Identification, And Control Of Tilt-Rotor Evtol Aircraft, Clayton T. Spencer

All Graduate Theses and Dissertations, Fall 2023 to Present

This thesis includes the development, modeling, identification, and control of an electric-Vertical-Take-Off-and-Landing (eVTOL) aircraft with tiltable rotors. The front two rotors have tilting capability for transition flight from vertical-take-off to forward-level flight. This work details the development of an eVTOL aircraft and the selection of sub components such as electric motors, batteries, and controllers. After the aircraft build, mathematical model is derived to describe the motion of the aircraft. Unknown parameters in the mathematical model are identified using a Least-Squares-regression (LSR) method that can handle parameter constraints. This is done using real flight data collected from the aircraft. Lastly, this …

Multifidelity Comparison Of Supersonic Wave Drag Prediction Methods Using Axisymmetric Bodies †, Troy Abraham, David Lazzara, Douglas Hunsaker

Mechanical and Aerospace Engineering Student Publications and Presentations

Low-fidelity analytic and computational wave drag prediction methods assume linear aerodynamics and small perturbations to the flow. Hence, these methods are typically accurate for only very slender geometries. The present work assesses the accuracy of these methods relative to high-fidelity Euler, compressible computational-fluid-dynamics solutions for a set of axisymmetric geometries with varying radius-to-length ratios (R/L). Grid-resolution studies are included for all computational results to ensure grid-resolved results. Results show that the low-fidelity analytic and computational methods match the Euler CFD predictions to around a single drag count (~1.0 × 10^–4) for geometries with R/L ≤ 0.05 …

Offshore Wind Farm Pycnocline Mixing From Varied Flow Types, Laura Lundahl

Student Research Symposium

As the demand for sustainable low carbon energy grows, offshore wind farms (OWFs) are becoming increasingly popular and are being pushed into stratified regions where a pycnocline exists (Figure 1). These wind farms may cause turbulent mixing of the pycnocline, which will harm the phytoplankton ecosystem. This project quantifies pycnocline mixing to gain knowledge of effective methods for mitigating harmful effects.

Simulating Low Gravity Particle-Laden Flow, Ryan Lewis

Student Research Symposium

No abstract provided.

High-Fidelity Turbulence Modelling Of Double-Diffusive Mixing In Buoyancy Driven Flows, Sanaz Izadifar

Student Research Symposium

Double-diffusive convection is the flow caused by buoyancy gradient in a fluid, where two different scalars cause density gradients, and each scalar has significantly different diffusion rates.

Wake Characteristics Of In-Phase And Out-Phase Array Of Oscillation Airfoils, Yi-Cheng Chen

Student Research Symposium

In order to solve the hydrodynamics of a school of fish using the open-source SEM solver Nek5000, an oscillating mesh is required to simulate fish oscillations and at the same time simplify the process of mesh partitioning and satisfy the limitation of nek5000 that the mesh must be quadrilateral.

Mechanical Property Variability In Lpbf Ss316l Due To Defects Formation And Process Interruption, Tasrif Ul Anwar

Student Research Symposium

This project aims to understand the correlation between the manufacturing process, defect formation, process interruptions, and the resulting properties of components made with laser powder bed fusion techniques.