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Space Vehicles

Air Force Institute of Technology

2018

Articles 1 - 8 of 8

Full-Text Articles in Engineering

Human Optimization And Performance Enhancement In Flight Via Real-Time Biofeedback (Project Have Hope), Michael S. Fritts Mar 2018

Human Optimization And Performance Enhancement In Flight Via Real-Time Biofeedback (Project Have Hope), Michael S. Fritts

Theses and Dissertations

A four-phase, chronological, and build-up approach was implemented that commenced with basic hardware testing in a centrifuge and culminated in flights augmented by real-time biofeedback displays. A prototype Portable Electrocardiogram Unit (PECGU) was designed and proven to accurately measure heart rate (HR) and display percent heart rate reserve (%HRR). Results showed that %HRR was not a sole predictor of cognitive state. Cognitive responses indicated some correlation with %HRR, but were influenced by environment (centrifuge vs. flight). Subjective perceived exertion levels did not show statistically significant changes during test with biofeedback. A G-tracking task was evaluated during centrifuge and flight tests. …

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Pseudo Linear Hall Effect Thruster Characterization Through Potential, Magnetic, And Optical Measurements, Braeden A. Sheets Mar 2018

Pseudo Linear Hall Effect Thruster Characterization Through Potential, Magnetic, And Optical Measurements, Braeden A. Sheets

Theses and Dissertations

Electric propulsion systems are a more mass efficient method for providing a change in velocity, ΔV, to on-orbit spacecraft, than their chemical counterparts. In comparison, electric systems generally have a much higher specific impulse, Isp, than chemical systems. One option within the realm of electric propulsion is Hall Effect Thrusters, which have moderately high specific impulse values. From their advent in the 1960s, Hall Effect Thrusters have been used for orbit station keeping, attitude control, and orbit transfer. Although the discharge cavity is conventionally circular, pseudo-linear or racetrack shaped cavities have been developed. Even though Hall thrusters have decades of …

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Design And Testing Of An Additively Manufactured Cubesat Structural Bus, Karson A. Roberts Mar 2018

Design And Testing Of An Additively Manufactured Cubesat Structural Bus, Karson A. Roberts

Theses and Dissertations

Recent innovations in additive manufacturing and design capabilities have opened the door for more opportunities to integrate multiple functions into a structural de- sign. Specifically, 3D printing through advanced laser powder bed fusion of metal powder allows for the development and integration of advanced structures that were previously unachievable. The demonstration of these techniques on a small satellite results in a structural bus consisting of various external and internal features, increasing its functionality and capabilities beyond simply providing structural support. 3D printing a multi-functional CubeSat bus with these integrated features such as internal lattices and wiring tabs demonstrates a new …

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Parameter Study Of An Orbital Debris Defender Using Two Team, Three Player Differential Game Theory, David F. Spendel Mar 2018

Parameter Study Of An Orbital Debris Defender Using Two Team, Three Player Differential Game Theory, David F. Spendel

Theses and Dissertations

The United States Air Force and other national agencies rely on numerous space assets to project their doctrine. However, space is becoming an increasingly congested, contested, and competitive environment. A common risk mitigation strategy for the orbit debris problem is either performing evasive maneuvers, or placing additional shielding on the satellite before launch. Current risk mitigation strategies have significant consequences to satellite operators and may not produce sufficient risk mitigation. This research poses that an orbital debris defender, which would defend the primary satellite from orbital debris, may be a more effective risk mitigation strategy. By assuming the worst case …

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Characterization And Analysis Of Plasma Instabilities In A 600 W Permanent Magnet Hall Thruster, Samuel D. Wright Mar 2018

Characterization And Analysis Of Plasma Instabilities In A 600 W Permanent Magnet Hall Thruster, Samuel D. Wright

Theses and Dissertations

Electric propulsion is an important technology for the future of space operations and exploration. Within the range of electric propulsion devices, Hall Effect Thrusters provide a balance of thrust and specific impulse well-suited for many Earth-centric missions. Hall Effect Thrusters have been studied since their development in the 1960s and have been flown on hundreds of spacecraft, but the intimate details of the plasma behavior within the thruster exhaust plume are still not well understood. Furthering this knowledge may be key to improving thruster design to yield better performance and longer lifetimes. To this end, experiments were conducted to measure …

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The Study And Application Of Carbon Nanotube Film Heaters For Space Applications, Christopher C. Rocker Mar 2018

The Study And Application Of Carbon Nanotube Film Heaters For Space Applications, Christopher C. Rocker

Theses and Dissertations

The purpose of this research was to examine the feasibility of using Carbon Nanotube (CNT) sheets as thin film heaters for space applications. The ability to maintain the temperature of space components has a direct impact on a space vehicle's operation and longevity. Currently etched foil heaters are used to heat satellite batteries. Battery heaters are the focus of this research. However, as this study will show, they have limitations and are susceptible to failure. CNT sheets have many beneficial properties and show potential in replacing the etched foil design. In this study test specimens were created by forming laminate …

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Space-Based Maneuver Detection And Characterization Using Multiple Model Adaptive Estimation, Justin D. Katzovitz Mar 2018

Space-Based Maneuver Detection And Characterization Using Multiple Model Adaptive Estimation, Justin D. Katzovitz

Theses and Dissertations

An increasingly congested space environment requires real-time and dynamic space situational awareness (SSA) on both domestic and foreign space objects in Earth orbits. Current statistical orbit determination (SOD) techniques are able to estimate and track trajectories for cooperative spacecraft. However, a non-cooperative spacecraft performing unknown maneuvers at unknown times can lead to unexpected changes in the underlying dynamics of classical filtering techniques. Adaptive estimation techniques can be utilized to build a bank of recursive estimators with different hypotheses on a system's dynamics. The current study assesses the use of a multiple model adaptive estimation (MMAE) technique for detecting and characterizing …

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Utilizing Supercomputing To Analyze Risks Of An Emergent Large-Scale Debris Field In Low Earth Orbit, David J. Buehler Mar 2018

Utilizing Supercomputing To Analyze Risks Of An Emergent Large-Scale Debris Field In Low Earth Orbit, David J. Buehler

Theses and Dissertations

The likelihood of on-orbit breakups, whether spontaneous or the result of collision, will likely continue to grow as the barriers of entry to and use of space are reduced. In all orbital regimes, especially low Earth orbit (LEO), preparation to respond quickly when the next breakup occurs is critical. This research utilizes high-performance parallel computation along with python-driven Systems Tool Kit (STK) to model a large-scale on-orbit breakup in LEO, with the goal of returning data in less than 90 minutes. The breakup is characterized by the National Aeronautics and Space Administration (NASA) EVOLVE 4.0 breakup model and is both …

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