Cubesat Development Framework,
2021
Air Force Institute of Technology
Cubesat Development Framework, William D. Sousa
Theses and Dissertations
AFITs Center for Space Research and Assurance (CSRA) has developed several small satellites without a detailed developmental framework in place but future work will focus on CubeSat development with the intent of managing multiple builds concurrently. With the goal of each satellite being completed in three years, a comprehensive process needs to be established. Research revealed that the Department of Defense (DoD), U.S. Air Force (USAF), and National Aeronautics and Space Administration (NASA) guidance on the acquisition and systems engineering processes require more reviews and deliverables than appropriate for CSRAs projects. The development processes from other universities divulge some aspects …
Satellite Tracking With Neuromorphic Cameras For Space Domain Awareness,
2021
Air Force Institute of Technology
Satellite Tracking With Neuromorphic Cameras For Space Domain Awareness, Joseph G. Bacon Jr.
Theses and Dissertations
A significant number of objects orbit the space around Earth. Each of these objects, be it debris, a functioning satellite, or even a staffed space station, circle the planet at extreme speeds relative to most objects on the Earth's surface. Any collision would result in disaster thanks to the extreme amount of kinetic energy involved. Space Domain Awareness (SDA) includes the detection, identification, cataloging, and tracking of orbiting objects to prevent such catastrophes. SDA is maintained in multiple ways to include radar, lidar, telescopes, and other sensors. This research investigates the maturing technology of neuromorphic cameras to determine their applicability …
Design And Analysis Of Air-Stiffened Vacuum Lighter-Than-Air Structures,
2021
Air Force Institute of Technology
Design And Analysis Of Air-Stiffened Vacuum Lighter-Than-Air Structures, Ruben Adorno-Rodriguez
Theses and Dissertations
Lighter-than-air (LTA) systems have been developed for numerous applications and have taken several forms. Airships, aerostats, blimps, and balloons are all part of this family of systems, which uses Archimedes principle to achieve neutral and positive buoyancy in air by replacing an air volume with LTA gases. These lifting gases stiffen the otherwise compliant envelope structures, allowing them to sustain the pressure difference brought by the displaced air. The compliance of these structures is a byproduct of the weight requirement, materials and geometrical arrangement of which these structures are built from, typically resulting in dimensionalities that exhibit low or virtually …
Cubesat Attitude Determination And Control System (Adacs) Characterization And Testing For Rendezvous And Proximity Operations (Rpo),
2021
Air Force Institute of Technology
Cubesat Attitude Determination And Control System (Adacs) Characterization And Testing For Rendezvous And Proximity Operations (Rpo), Steven T. Bednarski
Theses and Dissertations
This research endeavors to evaluate and characterize the performance of CubeSat specific commercial-off-the-shelf (COTS) Attitude Determination and Control Systems (ADACS) for Mission suitability. To ensure COTS components are capable of meeting CubeSat mission requirements, deliberate performance testing of critical CubeSat subsystems in flight-like conditions is essential. This effort focuses on testing the MAI-401 ADACS subsystem as configured to support the Grissom-1 CubeSat mission, as mounted to an air bearing, residing within a 3-axis Helmholtz Cage, and subjected to a simulated magnetic environment of various orbital parameters.
Applied Reachability Analysis For Time-Optimal Spacecraft Attitude Reorientations,
2021
Air Force Institute of Technology
Applied Reachability Analysis For Time-Optimal Spacecraft Attitude Reorientations, Layne C. Barrett
Theses and Dissertations
Satellite attitude reorientation has been of significant interest in astronautical engineering, and being able to reorient in a time-optimal manner has been of exceeding interest since the 1970s. Ensuring a spacecraft mission set can be conducted within a certain amount of time begs the question of whether or not a certain maneuver can be completed with a bounded control. This thesis answers that question by using the concept of reachability to provide reachable sets for different spacecraft reorientation scenarios. The reachable sets generated provide a range of initial states that guarantee a satellite reach a desired end orientation given a …
Cislunar Debris Propagation Following A Catastrophic Spacecraft Mishap,
2021
Air Force Institute of Technology
Cislunar Debris Propagation Following A Catastrophic Spacecraft Mishap, Nathan R. Boone
Theses and Dissertations
This research involves theoretical analysis of the short- and long-term motion of space debris in cislunar trajectories following a spacecraft catastrophic mishap. Specifically, the research formulates a debris propagation model using four-body dynamics and determines debris trajectories following breakup events for a variety of different initial orbital positions. A spacecraft survivability model is then used to quantify the risks from the debris to other cislunar spacecraft. First, a study of the risks due to natural debris comprising the Kordylewski clouds at the Earth-Moon ��4 and ��5 Lagrange points is conducted as an introduction to cislunar debris propagation. Next, …
Scaling Gas Turbine Film Cooling Adiabatic Effectiveness Through Simultaneous Matching Of Momentum Flux Ratio And Advective Capacity Ratio,
2021
Air Force Institute of Technology
Scaling Gas Turbine Film Cooling Adiabatic Effectiveness Through Simultaneous Matching Of Momentum Flux Ratio And Advective Capacity Ratio, Evan C. Glowiak
Theses and Dissertations
The study of gas turbine engine performance improvement requires extracting usable work from the hot section turbine. To prevent heat damage to turbine blades, film cooling is employed. Low temperature tests are conducted at ambient pressure on scale models to analyze the effects of gas flow parameters on scaling adiabatic effectiveness at easily repeatable conditions. This research aims to determine how matching coolant flow rate parameters Momentum Flux Ratio (I) and Advective Capacity Ratio (ACR) can scale adiabatic effectiveness on flat plate and leading edge geometries between air and carbon dioxide gas. Results indicate improvement in scaling adiabatic effectiveness when …
A Reduced Order Model Of The Celestial Icosahedron As The Substructure For A Lighter Than Air Vehicle,
2021
Air Force Institute of Technology
A Reduced Order Model Of The Celestial Icosahedron As The Substructure For A Lighter Than Air Vehicle, Torin C. Quick
Theses and Dissertations
A finite element approach was used to investigate a novel reduced order model to determine the minimum structure dimensionality to support vacuum for a VLTAV. This modeling technique represented the individual segments of the substructure as curved beams with clamped radially-resisted boundary conditions. The full structure was then modeled as a bare structure and structure with skin to validate the results of the reduced order model. The beam geometry for the material Ultem 9085 was determined through this process leading to the 3-D printing of the structure. It was then experimentally tested under uniaxial compression complimented with a FEA model.
Safe Spacecraft Rendezvous And Proximity Operations Via Reachability Analysis,
2021
Air Force Institute of Technology
Safe Spacecraft Rendezvous And Proximity Operations Via Reachability Analysis, Paul A. Grossi
Theses and Dissertations
The rapid expansion of the utilization of space by nations and industry has presented new challenges and opportunities to operate efficiently and responsibly. Reachability analysis is the process of computing the set of states that can be reached given all admissible controls and can be a valuable component in an autonomous mission planning system if conducted efficiently. In the current research, reachability analysis is used with several relative motion models to show that all ranges of orbits can be computed in milliseconds, and that it is a feasible approach for on-board autonomous mission planning. Reachability analysis is then combined with …
Hybridized Spacecraft Attitude Control Via Reinforcement Learning Using Control Moment Gyroscope Arrays,
2021
Air Force Institute of Technology
Hybridized Spacecraft Attitude Control Via Reinforcement Learning Using Control Moment Gyroscope Arrays, Cecily C. Agu
Theses and Dissertations
Machine learning techniques in the form of reinforcement learning (RL) can solve complex nonlinear problems found within spacecraft attitude determination and control systems (ADCS). Three CMG arrays were implemented in two simulated spacecraft environments using a reinforcement learning controller. The performance of the controllers were evaluated using target profiles from traditional control law implementations, singularity measure, and variable initial state values. The current research demonstrates that while RL techniques can be implemented, further exploration is needed to investigate the operational efficacy of an approach for producing comparable performance attributes with respect to traditional control laws.
Shock Migration On An Oscillating Straked Delta Wing Using An Unsteady Euler Solver,
2021
Air Force Institute of Technology
Shock Migration On An Oscillating Straked Delta Wing Using An Unsteady Euler Solver, Alexander J. Brown
Theses and Dissertations
This research contributes to the understanding of Shock Induced Trailing Edge Separation (SITES) as a driver of Limit Cycle Oscillation (LCO) by performing a computational investigation of nonlinear aerodynamic phenomena on a straked delta wing in transonic flow, oscillating in pitch. ZEUS, an Euler-based aeroelastic solver with a boundary layer coupling scheme meant to capture viscous flow effects within the boundary layer, was used to analyze aerodynamic flow around the wing for various mean incidence angles, oscillation amplitudes, and Mach numbers within the transonic region. The dynamic characteristics of the airflow around the wing were investigated in order to characterize …
Optimizing Design Parameters For Active Flow Control Boundary-Layer Fence Performance Enhancement On A Delta Wing,
2021
Air Force Institute of Technology
Optimizing Design Parameters For Active Flow Control Boundary-Layer Fence Performance Enhancement On A Delta Wing, Nathan L. Tedder
Theses and Dissertations
Utilizing computational fluid dynamic (CFD) simulations, the presented study is able to further the investigation of replicating and improving upon the performance of a NACA 0012 cropped half-span delta-wing at high angles-of-attack with an active flow control fluidic fence via wall-normal, steady blowing from an optimized single chordwise slot located at z/b = 70%,. The data is generated using CREATE-AV Kestrel v10.1rc5 CFD software on the Department of Defense High Performance Computing systems. The flight regime is held constant at a Mach number of 0.18 and a Reynolds number (Re) of 5.0 x 105, based on the root …
Real-Time Aerial Magnetic And Vision-Aided Navigation,
2021
Air Force Institute of Technology
Real-Time Aerial Magnetic And Vision-Aided Navigation, Daniel J. Clarke
Theses and Dissertations
Aerial magnetic navigation has shown to be a viable alternative navigation method that has the potential for world-wide availability, to include over oceans. Obtaining GPS-level accuracy using magnetic navigation alone is challenging, but magnetic navigation can be combined with other alternative navigation methods that are more posed to obtaining GPS-level accuracy in their current state. This research presents an aerial navigation solution combining magnetic navigation and vision-aided navigation to aid an inertial navigation system (INS). The navigation solution was demonstrated in real-time playback using simulated magnetic field measurements and flight-test captured visual imagery. Additionally, the navigation solution was flight-tested on …
Automated Find Fix And Track With A Medium Altitude Long Endurance Remotely Piloted Aircraft,
2021
Air Force Institute of Technology
Automated Find Fix And Track With A Medium Altitude Long Endurance Remotely Piloted Aircraft, Aubrey L. Olson
Theses and Dissertations
A limitation in RPA ISR operations is loss of target track if the command link is severed. For an RPA to effectively execute the ISR mission without a command link, it needs the capability to F2T targets autonomously. Automated Find Fix and Track (AFFTRAC) was developed to help solve this problem by demonstrating a proof of concept tactical autopilot. Monocular stereo vision was used to process sequential images acquired during orbit to produce a partial structural point cloud of the original structure. This partial structural point cloud was then exploited to create a holding area density for the aircraft to …
Impendance Probe Payload Development For Space-Based Joint Service Collaboration,
2021
Air Force Institute of Technology
Impendance Probe Payload Development For Space-Based Joint Service Collaboration, Brian T. Kay
Theses and Dissertations
Collaborations utilizing small spacecraft in near earth orbit between the U. S. Coast Guard Academy (CGA), Naval Research Lab (NRL), the U. S. Naval Academy (USNA), and the Air Force Institute of Technology (AFIT) have initiated scientific and engineering space-based experiments. Sourced opportunities like the VaSpace ThinSat missions have provided a platform for payload, sensor, and experiment development that would have otherwise been resource prohibitive. We have constructed an impedance probe payload derived from the existing ‘Space PlasmA Diagnostic suitE’ (SPADE) mission operating from NASA’s International Space Station. Currently both space and laboratory plasmas are investigated with AC impedance measurements …
Modeling Situation Awareness In A Uav Scenario Using Sysml,
2021
Air Force Institute of Technology
Modeling Situation Awareness In A Uav Scenario Using Sysml, Tommy R. Hernandez
Theses and Dissertations
The U.S. Department of Defense (DoD) is rapidly moving towards using increasingly automated systems. Unmanned Aerial Systems (UAS) will be used in contested environments where direct human control may be impossible for long stretches of time. This increase in automation brings with it challenges in maintaining resilient Situation Awareness (SA) for operators, who still need to set goals for the UAS to accomplish their missions. Simultaneously, the DoD is increasing the adoption of Model-Based Systems Engineering (MBSE) in the development of weapon systems. This thesis explores the use of SysML to model of an SA repair system for a UAS …
Modeling Aircraft Disturbance Fields For Magnetic Navigation Using Dense Anns And The Novel Manntl Architecture,
2021
Air Force Institute of Technology
Modeling Aircraft Disturbance Fields For Magnetic Navigation Using Dense Anns And The Novel Manntl Architecture, Kyle A. Emery
Theses and Dissertations
The ability to use GPS for navigation is becoming increasingly limited in certain areas of the world. Knowing this, the Air Force Research Labs is constantly looking for ways to improve alternate navigation methods such as magnetic navigation. In the interest of making advancements in aircraft disturbance field modelling, Lieutenant Emery recreates models from previous works to prove results. Lieutenant Emery also introduces a novel model architecture that attempts to mix the filtering properties of Tolles-Lawson with the non-linear capabilities of an artificial neural network. The introduction of this model could present better aircraft disturbance field modelling and in turn, …
Delayed Authentication System For Civilian Satellite,
2021
Air Force Institute of Technology
Delayed Authentication System For Civilian Satellite, Sean M. Feschak
Theses and Dissertations
This thesis presents the feasibility of a Delayed Authentication System (DAS) for civilian satellite navigation (satnav) receivers. In satnav systems, encrypted signal components are transmitted synchronously with civilian components. Hence, the civilian signals can be authenticated by detecting the presence of encrypted signal components within the received signal. To authenticate, a reference station transmits estimated encrypted signal spreading code symbols processed using a high gain antenna. In this thesis, it is shown that a 1-meter diameter dish antenna is adequate to provide a high probability of successful authentication, thereby reducing overall system complexity and cost.
Optimizing A Bank Of Kalman Filters For Navigation Integrity,
2021
Air Force Institute of Technology
Optimizing A Bank Of Kalman Filters For Navigation Integrity, Luis E. Sepulveda
Theses and Dissertations
Alternative navigation is an area of research which employs a variety of sensor technologies to provide a navigation solution in Global Navigation Satellite System degraded or denied environments. The Autonomy and Navigation Technology Center at the Air Force Institute of Technology has recently developed the Autonomous and Resilient Management of All-source Sensors (ARMAS) navigation framework which utilizes an array of Kalman Filters to provide a navigation solution resilient to sensor failures. The Kalman Filter array size increases exponentially as system sensors and detectable faults are scaled up, which in turn increases the computational power required to run ARMAS in areal-world …
Neuromorphic Vision Sensors For Space-Based Applications,
2021
Air Force Institute of Technology
Neuromorphic Vision Sensors For Space-Based Applications, Jessica L. Horn
Theses and Dissertations
This research examines the viability of event-based vision (neuromorphic) sensors for future use on satellites. Outputting single pixel events only when a change in intensity is detected, event-based vision sensors offer a potential low power, low latency, high temporal resolution, and high dynamic range solution as compared to traditional CCD or CMOS camera technology. The commercial off-the-shelf DVS240C sensor, is analyzed to determine if operability is affected by launch conditions and the low Earth space environment through vacuum, thermal vacuum, and vibration tests. No appreciable changes in sensor operation was observed throughout testing. Additionally, the sensor was able to detect …
