Formation Flight Of Earth Satellites On Kam Torus Using Classical Orbital Elements,
2017
Air Force Institute of Technology
Formation Flight Of Earth Satellites On Kam Torus Using Classical Orbital Elements, Marissa C. Reabe
Theses and Dissertations
This research uses the KAM theory that has been refined by Wiesel to show that Earth-satellites dynamics can be represented by an integrable Hamiltonian system with a small perturbation, like Earths geopotential. The satellite will follow a torus in phase space and remain on that KAM torus for all time unless acted on by a non-conservative force. A torus frequency was calculated, in this research, using a truth model in System Tool Kit (STK) and the High Precision Orbit Propagator (HPOP) to develop an accurate ephemeris file listing the Classical Orbital Elements (COEs). The frequencies found from the truth model …
Computational Optimization Under Uncertainty Of An Active Flow Control Jet,
2017
Air Force Institute of Technology
Computational Optimization Under Uncertainty Of An Active Flow Control Jet, Luke A. Welch
Theses and Dissertations
Optimization under uncertainty is performed to determine the optimal parameters of an active flow control jet to impart robust control during transonic cruise. A steady blowing jet is optimized on an airfoil to impart a change in lift greater than or equal to that generated by traditional control surfaces. The design candidates are computationally evaluated using the NASA flow solver, FUN3D, under 20 unique combinations of angle of attack, Reynolds number, and Mach number in order to propagate model input uncertainty. The mean change in lift and the associated standard deviation are included in the optimization framework to help ensure …
Evaluating The Autonomous Flying Qualities Of A Simulated Variable Stability Aircraft,
2017
Air Force Institute of Technology
Evaluating The Autonomous Flying Qualities Of A Simulated Variable Stability Aircraft, Ali M. Hamidani
Theses and Dissertations
Delivering communications from high altitudes, at airspeeds of just 30 knots, gathering data from active volcanoes and forming hurricanes, and collecting ISR over hostile territories, UAVs are at the ready to perform those missions that are too dull, dirty, or dangerous for manned aircraft. However, the proliferation of this new technology has its fair share of challenges. Over 460 DoD UAV mishaps have occurred since 2001, with almost half resulting in damages of $2M or more. One incident almost ended in fatalities, when a UAV, suffering from loss of control, collided with a C-130. That loss of control is what …
The Impact Of Atmospheric Fluctuations On Optimal Boost Glide Hypersonic Vehicle Dynamics,
2017
Air Force Institute of Technology
The Impact Of Atmospheric Fluctuations On Optimal Boost Glide Hypersonic Vehicle Dynamics, Melissa A. Dunkel
Theses and Dissertations
A project under the management of Air Force Research Laboratory has begun development of a six degree of freedom model for use in hypersonic vehicle development and application. One area of interest is the perturbation of vehicle behavior based on atmospheric fluctuations – how the performance of the vehicle changes with respect to “hot”, “cold” and standard day conditions. The method developed to fill this need uses real-world data from the Global Forecast System to create a “hot” and “cold” day dataset to compare with the standard day model. The key parameter is atmospheric density, a value calculated over a …
Time-Dependent Validation Of Finite Element Strain Distribution Of A Plastically-Deformed Plate Via Digital Image Correlation,
2017
Air Force Institute of Technology
Time-Dependent Validation Of Finite Element Strain Distribution Of A Plastically-Deformed Plate Via Digital Image Correlation, Kevin R. Knapp
Theses and Dissertations
Generation of residual stress is an essential step in the generation of Goodman data via Air Force Research Laboratory's vibration-based fatigue test. Conventional Goodman data is constructed through uniaxial fatigue testing at a rate of 40 Hz, while the vibration-based testing excites stresses at 1,600 Hz in a stress state that is similar to those seen in gas turbine engine airfoils. A pre-strain procedure is conducted to form residual tensile stress, which serves as a steady stress when the specimen is subjected to fully-reversed vibration-based fatigue loads. This steady tensile stress is desired at the fatigue zone of the test …
Investigating Analytical And Numerical Methods To Predict Satellite Orbits Using Two-Line Element Sets,
2017
Air Force Institute of Technology
Investigating Analytical And Numerical Methods To Predict Satellite Orbits Using Two-Line Element Sets, Adam T. Rich
Theses and Dissertations
As Low Earth Orbit (LEO) contains an ever-increasing number of objects, the prediction of future object positions must be precise in order to avoid collisions. Object positions are distributed in two-line element (TLE) sets and are generated using the analytical propagator known as Simplified General Perturbations 4 (SGP4). However, a numerical integrator called Special Perturbations (SP) provides an alternative approach to TLE generation and propagation. In this thesis, TLE accuracy was determined with both models, and the length of time that a single element set can provide valid information was also established. With two-line element sets as data, comparisons were …
Hall Effect Thruster Characterization Through Potential, Magnetic, And Optical Measurements,
2017
Air Force Institute of Technology
Hall Effect Thruster Characterization Through Potential, Magnetic, And Optical Measurements, Nicholas L. Hyatt
Theses and Dissertations
Electric propulsion is a promising method for providing ΔV to spacecraft on orbit. In general, much higher ISPS are obtained compared to their chemical counterparts. Hall thrusters are a subset of electric propulsion with moderately high specific impulse and thrust when compared to other forms of electric propulsion. Even though Hall thrusters have an extensive flight legacy around the world, there are still many unknowns associated with their operation. Experimental research was conducted in AFIT’s Space Propulsion Application Simulation System (SPASS) laboratory, to measure Hall current, plasma potential and visible emission from the 600W Hall thruster in a …
Modeling And Computation Of The Maximum Braking Energy Speed For Transport Category Airplanes,
2017
AAR Aerospace Consulting, LLC
Modeling And Computation Of The Maximum Braking Energy Speed For Transport Category Airplanes, Nihad E. Daidzic
Journal of Aviation Technology and Engineering
Transport-category or FAR/CS 25 certified airplanes may occasionally become braking energy capacity limited. Such limitation may exist when heavy airplanes are departing airports at high-density altitudes, on relatively long runways, and/or possibly with some tailwind component. A maximum braking energy VMBE speed exists which may limit the maximum allowable takeoff decision/action speed V1. The ever-existing possibility of high-speed rejected takeoff in such conditions may also limit the airplane gross weight for declared available distances. To gain deeper insights and acquire better understanding of the topic, a theoretical model of the maximum braking energy and the related VMBE speed for T-category …
P26. Global Exponential Stabilization On So(3),
2017
[email protected]
P26. Global Exponential Stabilization On So(3), Soulaimane Berkane
Western Research Forum
Global Exponential Stabilization on SO(3)
Collision Avoidance And Navigation Of Uas Using Vision-Based Proportional Navigation,
2017
Embry-Riddle Aeronautical University
Collision Avoidance And Navigation Of Uas Using Vision-Based Proportional Navigation, Matthew J. Clark
Doctoral Dissertations and Master's Theses
Electro-optical devices have received considerable interest due to their light weight, low cost, and low algorithm requirements with respect to computational power. In this thesis, vision-based guidance laws are developed to provide sense and avoid capabilities for unmanned aerial vehicles (UAVs) operating in complex environments with multiple static and dynamic collision threats. These collision avoidance guidance laws are based on the principle of proportional navigation (Pro-Nav), which states that a UAV is on a collision course with another vehicle or object if the line-of-sight (LOS) angles to the object remain constant. The guidance laws are designed for use with monocular …
The Collisional Evolution Of Orbital Debris In Geopotential Wells And Disposal Orbits,
2017
California Polytechnic State University, San Luis Obispo
The Collisional Evolution Of Orbital Debris In Geopotential Wells And Disposal Orbits, Benjamin Polzine
Master's Theses
This thesis investigates the orbital debris evolution in the geosynchronous disposal orbit regime and within geosynchronous orbits effected by the geopotential wells. A propagator is developed for the accurate simulation of GEO specific orbits and the required perturbations are determined and described. Collisions are then simulated in the selected regimes using a low velocity breakup model derived from the NASA EVOLVE breakup model. The simulations described in this thesis consider a set of perturbations including the geopotential, solar and lunar gravity, and solar radiation pressure forces. This thesis is based on a prior paper and additionally seeks to address an …
Orbital Determination Feasibility Of Leo Nanosatellites Using Small Aperture Telescopes,
2017
California Polytechnic State University, San Luis Obispo
Orbital Determination Feasibility Of Leo Nanosatellites Using Small Aperture Telescopes, Michael R. Strange
Master's Theses
This thesis is directed toward the feasibility of observing satellites on the nano scale and determining an accurate propagated orbit using a Meade LX600-ACF 14” diameter aperture telescope currently located on the California Polytechnic State University campus. The optical telescope is fitted with an f/6.3 focal reducer, SBIG ST-10XME CCD camera and Optec TCF-S Focuser. This instrumentation allowed for a 22’ X 15’ arcminute FOV in order to accurately image passing LEO satellites. Through the use of the Double-r and Gauss Initial Orbit Determination methods as well as Least Squared Differential Correction and Extended Kalman Filter Orbit Determination methods, an …
Decibel Notes,
2017
Morehead State University
Decibel Notes, Robert J. Twiggs
Robert "Bob" Twiggs STEM Education Collection
A class notes on "Decibel Notes" created by Professor Bob Twiggs on February 27, 2017.
Phonon Interference In Crystalline And Amorphous Confined Nanoscopic Films,
2017
Missouri University of Science and Technology
Phonon Interference In Crystalline And Amorphous Confined Nanoscopic Films, Zhi Liang, Thomas E. Wilson, Pawel Keblinski
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Using Molecular Dynamics Phonon Wave Packet Simulations, We Study Phonon Transmission Across Hexagonal (H)-BN and Amorphous Silica (A-SiO2) Nanoscopic Thin Films Sandwiched by Two Crystalline Leads. Due to the Phonon Interference Effect, the Frequency-Dependent Phonon Transmission Coefficient in the Case of the Crystalline Film (Si|h-BN|Al Heterostructure) Exhibits a Strongly Oscillatory Behavior. in the Case of the Amorphous Film (Si|a-SiO2|Al and Si|a-SiO2|Si Heterostructures), in Spite of Structural Disorder, the Phonon Transmission Coefficient Also Exhibits Oscillatory Behavior at Low Frequencies (Up to ∼1.2 THz), with a Period of Oscillation Consistent with the Prediction from the Two-Beam …
Surrogate Modeling Of Ultrasonic Simulations Using Data-Driven Methods,
2017
Missouri University of Science and Technology
Surrogate Modeling Of Ultrasonic Simulations Using Data-Driven Methods, Xiaosong Du, Robert Grandin, Leifur Leifsson
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Ultrasonic testing (UT) is used to detect internal flaws in materials and to characterize material properties. In many applications, computational simulations are an important part of the inspection-design and analysis processes. Having fast surrogate models for UT simulations is key for enabling efficient inverse analysis and model-assisted probability of detection (MAPOD). In many cases, it is impractical to perform the aforementioned tasks in a timely manner using current simulation models directly. Fast surrogate models can make these processes computationally tractable. This paper presents investigations of using surrogate modeling techniques to create fast approximate models of UT simulator responses. In particular, …
In-House Fabrication Of Temperature Sensitive Paint For Turbine Cooling Research,
2017
Embry-Riddle Aeronautical University
In-House Fabrication Of Temperature Sensitive Paint For Turbine Cooling Research, Mayur D. Patel, Mark A. Ricklick
Beyond: Undergraduate Research Journal
The Temperature Sensitive Paint (TSP) is a widely used method in measuring and visualizing flow separation and heat transfer. Compared to the cost and time consumption needed for methods such as pitot tubes, temperature sensitive paint is a cheaper alternative. Due to high usage in College of Engineering research projects, it was determined that in house fabrication of temperature sensitive paint would reduce time and cost limitations. For initial stages, literature research was performed to determine the recipe of intensity based TSP with luminophore and polymer binder that operated optimum at temperatures from 0-100°C. Europium III thenoyltrifluoroacetonate was determined to …
Method And Apparatus For Singularity Avoidance For Control Moment Gyroscope (Cmg) Systems Without Using Null Motion,
2017
Air Force Institute of Technology
Method And Apparatus For Singularity Avoidance For Control Moment Gyroscope (Cmg) Systems Without Using Null Motion, Brij N. Agrawal, Jae Jun Kim, Timothy Andrew Sands
AFIT Patents
A method is described for avoiding gyroscopic singularities during attitude correction to a system, such as a spacecraft having a CMG array. The method receives a corrective torque vector μ and gimbal angle values δ for each of at least three gimbals within the CMG array. The method generates a Jacobian matrix A as a function of gimbal angle values δ. The method calculates a determinant D of Jacobian matrix A. If the determinant is not equal to zero, it is not singular, and the method calculates a gimbal rate {dot over (δ)} using a pseudo-inverse steering law equation. If …
Determining Power For A Cubesat,
2017
Morehead State University
Determining Power For A Cubesat, Robert J. Twiggs
Robert "Bob" Twiggs STEM Education Collection
A PowerPoint Presentation created by Professor Bob Twiggs titled "Determining Power for a CubeSat" from February 3, 2017.
The Effect Of Biocomposite Material In A Composite Structure Under Compression Loading,
2017
California Polytechnic State University, San Luis Obispo
The Effect Of Biocomposite Material In A Composite Structure Under Compression Loading, Benjamin Andrew Sweeney
Master's Theses
While composite structures exhibit exceptional strength and weight saving possibilities for engineering applications, sometimes their overall cost and/or material performance can limit their usage when compared to conventional structural materials. Meanwhile ‘biocomposites’, composite structures consisting of natural fibers (i.e. bamboo fibers), display higher cost efficiency and unique structural benefits such as ‘sustainability’. This analysis will determine if the integration of these two different types of composites are beneficial to the overall structure. Specifically, the structure will consist of a one internal bamboo veneer biocomposite ply; and two external carbon fiber weave composite plies surrounding the bamboo biocomposite. To acquire results …
Professional Pilot Commercial Off-The-Shelf (Cots) Efb Usage, Policies And Reliability,
2017
Middle Tennessee State University
Professional Pilot Commercial Off-The-Shelf (Cots) Efb Usage, Policies And Reliability, Tyler A. Babb
International Journal of Aviation, Aeronautics, and Aerospace
Electronic Flight Bags (EFBs) have flooded the aviation industry. Commercial off-the-shelf (COTS) tablets are now commonly used by pilots as EFBs. Operators use EFBs for ease of use, faster access to information, to remove weight from the aircraft, and to increase pilots’ quality of life. Identifying trends in EFB usage among professional pilots could benefit operators and universities with flight training programs. EFB policies and procedures may vary among operators but achieve FAA compliance. This study identified these policies and procedures. The types of devices and software vary, and identifying these devices and software could be useful. This research used …
