Aerospace Engineering Commons^™

Relative Orbital Motion Dynamics With Respect To A Rotating Spacecraft-Fixed Frame, Nicholas Ortolano, David K. Geller, Aaron Avery

Space Dynamics Laboratory Publications

The Clohessy-Wiltshire equations are commonly used to describe the relative orbit motion of two spacecraft in proximity to each other. The relative motion solution provided by these equations is most naturally given in a local-vertical, local horizontal frame. However, if a nearby spacecraft is spinning in a controlled or uncontrolled manner, it may be more convenient to describe the relative orbital motion in the rotating spacecraft-fixed frame. This may be especially true for satellite inspection or approach to a spinning spacecraft. In this paper a set of linear-time-varying differential equations describing the orbital relative motion of two spacecraft as observed …

Cadet: Uhf & Uhf Plus S-Band Radios, Space Dynamics Laboratory

Space Dynamics Laboratory Publications

With the increase in Government-funded and industry small satellites missions, the need for a more robust communication infrastructure is critical for the CubeSat community. As part of the solution, SDL provides the Cadet U and Cadet PLUS radios as powerful communications tools ideal for small satellites. These affordable solutions are available in both UHF (Cadet U) and UHF plus S-Band (Cadet PLUS) configurations. The Cadet radios are compact, power efficient, high data rate transceivers. SDL optimized the design, from the electronics to the modes of operation, for low power consumption.

Nsgt: Software-Defined Nanosatellite Ground Transceiver, Space Dynamics Laboratory

Space Dynamics Laboratory Publications

Ground station operators need an affordable, configurable solution to communicate with small satellite radios.

SDL’s software-defined nanosatellite ground transceiver is low cost and highly configurable. It is compatible with a broad range of industry radios, including SDL’s Cadet U and Cadet PLUS.

The nanosatellite ground transceiver can also be used for benchtop testing during spacecraft integration.

Enhancement Of Volumetric Specific Impulse In Htpb/Ammonium Nitrate Mixed Hybrid Rocket Systems, Jacob Ward Forsyth

All Graduate Plan B and other Reports, Spring 1920 to Spring 2023

Hybrid rocket systems are safer and have higher specific impulse than solid rockets. However, due to large oxidizer tanks and low regression rates, hybrid rockets have low volumetric efficiency and very long longitudinal profiles, which limit many of the applications for which hybrids can be used. This research investigates a method for increasing the volumetric efficiency and improving the form factor of hybrid rocket systems by a non-combustible load of solid oxidizer to the hybrid fuel grain. Including such oxidizers increases the regression rate of the fuel and lowers the amount of fluid oxidizer needed for optimal combustion. This type …

'My Entire Life Has Been Influenced By The Space Industry’ | College Of Engineering, Usu College Of Engineering

College of Engineering News

Published in Creating Tomorrow – Oct. 15, 2016 – Jessica Gregory remembers looking up on her way to elementary school and seeing rockets blaze into the morning skies. She was raised near Santa Maria, Calif., in the 1980s at a time when rocket launches from nearby Vandenberg Air Force Base were a common sight.

Multispectral Optical Telescope Alignment Testing For Cryogenic Space Environment, Trent Newswander, Preston Hooser, James Champagne

Space Dynamics Laboratory Publications

Multispectral space telescopes with visible to long wave infrared spectral bands provide difficult alignment challenges. The visible channels require precision in alignment and stability to provide good image quality in short wavelengths. This is most often accomplished by choosing materials with near zero thermal expansion glass or ceramic mirrors metered with carbon fiber reinforced polymer (CFRP) that are designed to have a matching thermal expansion. The IR channels are less sensitive to alignment but they often require cryogenic cooling for improved sensitivity with the reduced radiometric background. Finding efficient solutions to this difficult problem of maintaining good visible image quality …

Propulsion Theory Of Flapping Airfoils, Comparison With Computational Fluid Dynamics, Doug F. Hunsaker, W. F. Phillips

Mechanical and Aerospace Engineering Faculty Publications

It is shown that the time-dependent aerodynamic forces acting on a flapping airfoil in forward flight are functions of both axial and normal reduced frequencies. The axial reduced frequency is based on the chord length, and the normal reduced frequency is based on the plunging amplitude. Furthermore, the time-dependent aerodynamic forces are related to two Fourier coefficients, which are evaluated here from computational results. Correlation equations for these Fourier coefficients are obtained from a large number of grid- and time-step-resolved inviscid computational-fluid-dynamics solutions, conducted over a range of both axial and normal reduced frequencies. The correlation results can be used …

Enhanced Thermal Conductance Of Polymer Composites Through Embedding Aligned Carbon Nanofibers, David S. Wood, Dale K. Hensley, Nicholas A. Roberts

Mechanical and Aerospace Engineering Faculty Publications

The focus of this work is to find a more efficient method of enhancing the thermal conduc-tance of polymer thin films. This work compares polymer thin films embedded with randomly oriented carbon nanotubes to those with vertically aligned carbon nanofibers. Thin films embedded with carbon nanofibers demonstrated a similar thermal conductance between 40–60 µm and a higher thermal con-ductance between 25–40 µm than films embedded with carbon nanotubes with similar volume fractions even though carbon nanotubes have a higher thermal conductivity than carbon nanofibers.

Multi-Static Mimo Along-Track Interferometry (Atl), Chad Knight, Ross Deming, Jake Gunther

Space Dynamics Laboratory Publications

Along-track interferometry (ATI) has the ability to generate high-quality synthetic aperture radar (SAR) images and concurrently detect and estimate the positions of ground moving target indicators (GMTI) with moderate processing requirements. This paper focuses on several different ATI system configurations, with an emphasis on low-cost configurations employing no active electronic scanned array (AESA). The objective system has two transmit phase centers and four receive phase centers and supports agile adaptive radar behavior. The advantages of multistatic, multiple input multiple output (MIMO) ATI system configurations are explored. The two transmit phase centers can employ a ping-pong configuration to provide the multistatic …

Investigating The Effect Of Capping Layers On Final Thin Film Morphology After A Dewetting Process, Benjamin C. White

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Nanoparticles on a substrate have numerous applications in nanotechnology, from enhancements to solar cell efficiency to improvements in carbon nanotube growth. Producing nanoparticles in a cheap fashion with some control over size and spacing is difficult to do, but desired. This work presents a novel method for altering the size and spacing of nickel and gold nanoparticles. Dewetting is a methodology to reduce thin films to an ensemble of discrete droplets. The introduction of alumina capping layers to thin nickel films during a pulsed laser-induced dewetting process has yielded reductions in the mean and standard deviation of radii and pitch …

Development Of A Three-Dimensional High-Order Strand-Grids Approach, Oisin Tong

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The strand-Cartesian grid approach is a unique method of generating and computing fluid dynamic simulations. The strand-Cartesian approach provides highly desirable qualities of fully-automatic grid generation and high accuracy. This work focuses on development of a high-accuracy methodology (high-order scheme) on strand grids for two and three dimensions.

In this work, the high-order scheme is extended to high-Reynolds number computations in both two and three dimensions with the Spalart-Allmaras turbulence model and the Menter SST turbulence model. In addition, a simple limiter is explored to allow the high-order scheme to accurately predict discontinuous flows.

Extensive verification and validation is conducted …

Effects Of Radiation Heating On Additively Printed Hybrid Fuel Grain Oxidizer-To-Fuel Ratio Shift, Stephen L. Merkley

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This thesis examined the hypothesis that radiative heat transfer in small-scale printed-fuel hybrid rocket motors is responsible for the observed decreasing oxidizer-to-fuel (O/F) ratio shift. The magnitude of the radiation term was negligible for the motor sizes and types of propellants that have been previously tested, but was reintroduced in this study. To prove this hypothesis, a detailed enthalpy balance model was developed and tested using experimental fuel regression rate data obtained from a variety of motor scales using additively-manufactured acrylonitrile butadiene styrene (ABS) fuel grains.

Impact Of Mass And Bond Energy Difference And Interface Defects On Thermal Boundary Conductance, Changjin Choi

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Many portions of energy generated in the U.S. are not used and take the form of wasted heat due to a poor heat transfer efficiency. This fact leads research communities to focus on thermoelectrics as a means for using waste heat through direct thermal to electrical energy conversion. One way to enhance thermoelectric efficiency is to reduce thermal conductivity through nanostructuring. In nanostructures, understanding energy transport across the interface of two materials is important because interfaces dominate the resistance to overall thermal transport of the system and can be described by thermal boundary conductance (TBC). Also of note, an understanding …

Effects On A Wedge Flowmeter Installed Downstream Of A Double Elbow Out Of Plane, Devan S. Radle

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Precise flow measurement is a critical part of many industries including industrial, hydropower, petroleum, nuclear, and water/wastewater. Lengthy upstream piping is required for many flowmeters to obtain accurate results. Due to piping constraints, sub- optimal flow meter installations can occur. One of these conditions is the installment of a flow meter in close proximity downstream of a double elbow out of plane (DEOP). A DEOP can cause swirl to form in the flow and can cause inaccurate metering results due to the non-uniform flow and pressure conditions. This study investigated the effect of installing a differential pressure producing wedge flow …

Benchmark Experiments For Natural Convection In Nuclear Fuel Rod Bundles, Kyle L. Jones

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Buoyancy is the mechanism through which heated air causes fluid motion due to a difference in temperature between a body and the surrounding fluid. This fluid motion can be very erratic and unstable, which creates a difficult problem when attempting to simulate this fluid motion. Using high performance computational power the capability of simulating these complex interactions is available but requires assessment to determine the accuracy of these difficult flow scenarios. This study provides experimental data that can be used to assess the simulation’s accuracy and to ensure the computational models are achieving the correct solution. The Rotatable Buoyancy Tunnel …

Microalgae Sorption Of Ten Individual Heavy Metals And Their Effects On Growth And Lipid Accumulation, Eric M. Torres

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The purpose of this study is to determine the potential microalgae have for being a heavy metal remediation tool. Heavy metals are naturally occurring elements that can be found inside the earth or on its surface. Typically, heavy metals are found naturally at low concentrations. However, through human activities, heavy metals are continually making their way to the surface and being concentrated. This happens largely through mining and manufacturing operations. For example, NiCd batteries produce waste containing nickel and cadmium, and paper manufacturing produces waste containing high levels of lead. As underdeveloped nations continue to industrialize and the world population …

Path Following By A Quadrotor Using Virtual Target Pursuit Guidance, Abhishek Manjunath

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Missile guidance laws have been solely developed to follow and intercept a target thereby destroying or damaging it. In this research, the primary objective is to modify and adopt a missile guidance law to be used on a quadrotor to follow a virtual target. The target is termed 'virtual' as it only exists mathematically in the form of equations. The goal is to have the quadrotor successfully following the predefined path (described by the target) while maintaining a fixed distance from the virtual target. To ensure viability and assess performance, a detailed comparison with another path following law is made.

Quadrotor Uav Path Following Using Trajectory Shaping, Parwinder Singh Mehrok

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The propose of this research is to develop a path following control law known as Trajectory Shaping. The approach is to develop a three- dimensional (3D) version of it from an existing two-dimensional (2D) model. Apart from research on this 3D control law, a multirotor unmanned aerial vehicle (UAV) platform, having four rotors and known as quadrotor is designed from the ground up for validating the concept of path following. Several pre-defined paths like the circle and figure-eight trajectories are used to apply the newly developed version of this control law. The existing 2D concept of Trajectory Shaping guidance …

Throttleable Gox/Abs Launch Assist Hybrid Rocket Motor For Small Scale Air Launch Platform, Zachary S. Spurrier

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The ability for an aircraft-based launch platform to place an orbital payload onto a nominal launch trajectory at a higher energy state -- altitude, velocity, flight path angle, and azimuth --using highly-efficient air breathing propulsion instead of a much lower-efficiency rocket system, offers the potential for a significantly smaller launch vehicle. An airborne platform also provides the ability to launch from multiple locations and allows for significantly increased "system responsiveness." The NASA Armstrong Flight Research Center’s Towed Glider Air-Launch System (TGALS) is a small-scale flight research project investigating the feasibility for a remotely-piloted, towed, glider system to act as a …

Shield: Shotgun Interdiction Of Enemy Low-Flying Drones, Space Dynamics Laboratory

Space Dynamics Laboratory Publications

When conventional disruption and neutralization methods fail, it’s time to choose a kinetic solution. SHIELD is a preliminary concept for an automatic, state-of-the art kinetic defense system. Drones can be eliminated at ranges up to 100 meters. The SHIELD weapon system design consists of an ultra-reliable, high-capacity, semiautomatic shotgun with tungsten shot. This weapon system is coupled with precision pointing, target tracking, and real-time ballistics, ensuring high first-round hit probability. Battle-network capable, SHIELD can perform slew-to-cue operations and cue other networked systems.

Celis: Compact Eyesafe Lidar System, Space Dynamics Laboratory

Space Dynamics Laboratory Publications

SDL has developed a novel Compact Eyesafe Lidar System (CELiS) designed to monitor airborne particulate matter (PM) emissions. It uses a 1.57 µm wavelength commercial laser, an 8 inch off-axis parabolic mirror, and a 200 µm diameter InGaAs avalanche photodetector (APD). The laser, mirror, and APD are mounted on a carbon fiber breadboard and housed in an environmentally-sealed housing. CELiS can operate over an 80°C temperature range with an optical path change of only 100 µm.

Rdg: Remote Door Gunner, Space Dynamics Laboratory

Space Dynamics Laboratory Publications

Leveraging decades of experience in precision optical and spacecraft pointing systems, SDL developed the Remote Door Gunner (RDG) system, a M240/M134 door gunner station. RDG was designed for operation inside a UH-60 Black Hawk helicopter.

Calibration Considerations For A Reduced-Timeline Optimized Approach For Vnir Earth-Orbiting Satellites, Zachary Bergen, Joe Tansock

Space Dynamics Laboratory Publications

With the increasing number of commercial satellite constellations launching, the need for calibration remains as relevant as ever. Some of these instruments are built with COTS optical components and, given the number and need for timely calibration, a flexible, dynamic, and streamlined approach is necessary for reproducibility, regression testing, adaptability, and high-quality image data. We present a use case for a commercial VNIR payload and demonstrate techniques and a storyboard of our experience. We ran a calibration campaign on a 100” focal length telescope assembled in a payload of approximate 50kg containing a commercial Bayer pattern camera of medium resolution …

Design And Use Of The Ionospheric Connection Explorer Payload Mockup, Burt Lamborn, John Elwell, Andy Little, William Craig, Rich Rynders, Eric Moulton

Space Dynamics Laboratory Publications

The Ionospheric Connection Explorer (ICON) satellite contains six science instruments that are integrated into a small volume on a single payload interface plate (PIP). Integrating these six instruments onto a single deck was challenging and complex in part due to their different physical configurations. After investigating various methods of reducing integration schedule and risk, an innovative approach of creating a high-fidelity full-scale mockup using 3D printed parts was chosen to address these concerns. This mockup included all instruments, the PIP, and associated harnessing, plumbing, and blanketing components. While the mockup integration effort yielded invaluable information for the flight payload integration, …

Di2e: Defense Intelligence Information Enterprise, Space Dynamics Laboratory

Space Dynamics Laboratory Publications

The rising demand for rapid intelligence software solutions combined with limited Government funding has highlighted the need for an organized process to use resources more efficiently. The solution needed to leverage existing capabilities to meet mission needs and ensure that defense intelligence information flows seamlessly across enterprise boundaries. In response, as a Government initiative, the NRO and AFRL developed the Defense Intelligence Information Enterprise (DI2E) framework as a solution to promote intelligence software asset reuse where possible.

Experimental Validation Data For Cfd Of Forced Convection On A Vertical Flat Plate, Jeff R. Harris, Blake W. Lance, Barton L. Smith

Mechanical and Aerospace Engineering Faculty Publications

A CFD validation data set for turbulent forced convection on a vertical plate is presented. The design of the apparatus is based on recent validation literature and provides a means to simultaneously measure boundary conditions and system response quantities. All important inflow quantities for RANS CFD are also measured. Data are acquired at two heating conditions and cover the range 40;000 < Rex < 300;000, 357 < Red2 < 813 and 0:02 < Gr/Re2 < 0:232. The data and uncertainties are contained in files in the supplemental material

Lightweight Deployment Mechanism Of Solar Arrays For Use In Cubesats, John Wood Ellis

Undergraduate Honors Capstone Projects

Cube satellites, also referred to as CubeSats, were developed in the late twentieth century, and have since served as a cost-effective method of gathering out-of-this-world data. The development of these small-scale satellites have helped universities and small companies worldwide to perform important experiments, as well as gather critical data in order to provide for further space exploration. Cube satellites are designed to be self-sustaining, by using solar cells to capture impinging thermal energy and convert it to power to be consumed by the electronics housed within the satellite itself. In order to function properly, these cells are extended in an …

Software-And Hardware-In-The-Loop Verification Of Flight Dynamics Model And Flight Control Simulation Of A Fixed-Wing Unmanned Aerial Vehicle, Calvin Coopmans, Michal Podhradsk, Nathan V. Hoffer

Mechanical and Aerospace Engineering Faculty Publications

Unmanned aerial system (UAS) use is ever-increasing. In this paper, it is shown that even with low-cost hardware and open-source software, simple numerical testing practices (software- and hardware-in-the-loop) can prove the accuracy and usefulness of an aeronautical flight model, as well as provide valuable pre-flight testing of many situations typically only encountered in flight: high winds, hardware failure, etc. Software and hardware simulation results are compared with actual flight testing results to show that these modeling and testing techniques are accurate and provide a useful testing platform for a small unmanned aerial vehicle. Source code used in simulation is open …

Wideband Fluorescence-Based Thermometry By Neural Network Recognition: Photothermal Application With 10 Ns Time Resolution, Liwang Liu, Kuo Zhong, Troy Munro, Salvador Alvarado, Renaud Cote, Sebastiaan Creten, Eduard Fron, Heng Ban, Mark Van Der Auweraer, N. B. Roozen, Osamu Matsuda, Christ Glorieux

Mechanical and Aerospace Engineering Faculty Publications

Neural network recognition of features of the fluorescence spectrum of a thermosensitive probe is exploited in order to achieve fluorescence-based thermometry with an accuracy of 200 mK with 100 MHz bandwidth, and with high robustness against fluctuations of the probe laser intensity used. The concept is implemented on a rhodamine B dyed mixture of copper chloride and glycerol, and the temperature dependent fluorescence is investigated in the temperature range between 234 K and 311 K. The spatial dependence of the calibrated amplitude and phase of photothermally induced temperature oscillations along the axis of the excitation laser are determined at different …

Thermal Earth Resource Monitoring Instrument (Thermi) Size, Weight And Power (Swap) Reduction, T. Newswander, Z. Bergen, J. Hancock, S. Hansen, A. Shumway, J. Stauder, D. Williams

Space Dynamics Laboratory Publications

The Thermal Earth Resource Monitoring Instrument (THERMI) has been designed to meet stringent Landsat heritage requirements with reduced size, weight and power (SWaP). The instrument design provides Earth resource monitoring through the use of two long-wave infrared bands that measure the land surface temperatures. These bands are especially valuable for monitoring water resources and water use. Instrument subsystems, including electronics, cryocooler, thermal management, optical telescope assembly, focal plane module, in-flight calibrator, and scene select mirror were studied and conceptually designed to reduce overall THERMI SWaP. Reductions in SWaP make it possible for THERMI to fit on a small satellite bus …