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Astrodynamics

Air Force Institute of Technology

2018

Articles 1 - 6 of 6

Full-Text Articles in Engineering

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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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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Optimal Trajectory Generation In A Dynamic Multi-Body Environment Using A Pseudospectral Method, Jacob A. Dahlke Mar 2018

Optimal Trajectory Generation In A Dynamic Multi-Body Environment Using A Pseudospectral Method, Jacob A. Dahlke

Theses and Dissertations

High-altitude parking orbits could provide resiliency to the military space infrastructure by providing redundancy in key assets, allowing for rapid reconstitution of underperforming satellites. When analyzing trajectories in a high-altitude regime, two-body models of Keplerian motion become less accurate since the gravitational effects of other bodies are no longer negligible. To provide a higher fidelity model of the dynamics in a high-altitude regime, a multiple-body model can be used. In the Earth-Moon system, a spacecraft operating in the high-altitude regime can be modeled with three-body dynamics. With certain simplifying assumptions, the model is called the circular-restricted three-body problem (CR3BP). The …

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Algorithms For Small Satellite Formation Flying, Robert B. Larue Mar 2018

Algorithms For Small Satellite Formation Flying, Robert B. Larue

Theses and Dissertations

This thesis presents algorithms for spacecraft formation flying using impulsive thrust and low-thrust methods. The general circular orbit formation initial conditions are derived in terms of equinoctial elements. Physical significance of the bounded relative motion parameters is presented for the case of general circular orbits. The developed algorithms are posed in terms of equinoctial elements for a singularity-free approach. The algorithms are assessed by numerical propagation of the inertial equations of motion with J2 and drag perturbations. Methods are presented for minimizing the ΔV required for formation initialization. An examination of the performance of open-loop and closed-loop control is provided …

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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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