Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 17 of 17 for “"Spacecraft System"”.
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Spacecraft system-level integration and test discrepancies : characterizing distributions and costs
… is to characterize the distribution and costs of spacecraft discrepancies found at the system level of integration and test, as well as understand the implications of those distributions and costs for the spacecraft enterprise as a whole. If discrepancies can be better understood, they can …
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Deep-Learning Based Multiple-Model Bayesian Architecture for Spacecraft Fault Estimation
… of an intelligent architecture designed for spacecraft fault estimation. The approach incorporates a collection of systematically organized autoencoders within a Bayesian framework, enabling early detection and classification of various spacecraft faults such as reaction-wheel damage, sensor …
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Design methodology for a neural network-based telemetry monitor
… framework for an artificial neural network-based system that is capable of fulfilling monitoring and control requirements of future aerospace missions. Incorporated into this framework are a newly developed training algorithm and the concept of cooperative network architectures. The feasibility of …
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System design visualizations for synthesizing intent specifications
… faced not only with the challenges of developing spacecraft and supporting technologies to explore the unknown, but they must do so successfully with tighter budgets and fewer personnel. Mission failure causes publicity that the industry cannot afford in this economy. To maintain project schedules …
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Flight test of a supersonic decelerator on Earth to simulate a Mars entry
A systems analysis is presented for simulation of the descent of a decelerator (parachute) and spacecraft for entry through the atmosphere of the planet Mars by a flight test in the Earth's atmosphere. Engineering atmosphere models for Mars are defined and based on these models requirements for …
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Implementation of ACCI Test Vehicle
The main challenge in commissioning a spacecraft system is the time it takes to design, build, integrate, launch, and bring online a given system. Air Force Research Lab (AFRL) has envisaged transforming these processes into what it calls “six-day spacecraft†in the next decade. The six-day …
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Timed model-based programming : executable specifications for robust mission-critical sequences
… is growing demand for high-reliability embedded systems that operate robustly and autonomously in the presence of tight real-time constraints. For robotic spacecraft, robust plan execution is essential during time-critical mission sequences, due to the very short time available for recovery from …
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Design of an Attitude Control System for a Spacecraft with Propellant Slosh Dynamics
<p>The presence of propellant slosh dynamics in a spacecraft system during a maneuver leads to attitude control system (ACS) performance degradation resulting in attitude tracking errors and instability. As spacecraft missions become more complex and involve longer durations, a substantial …
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Simulation development and analysis of attitude-control system architectures for an astronaut mobility unit
Control-moment gyroscopes (CMGs) are spacecraft attitude-control actuators which control the spacecraft's orientation and pointing. CMGs operate on electrical power and therefore obey the the conservation of angular momentum. Single-gimbal CMGs are equipped with a high-speed flywheel which can be …
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Nutation in the spinning SPHERES spacecraft and fluid slosh
Spacecraft today are often spin-stabilized during a portion their launch or mission. Though the basics of spin stabilization are well understood, there remains uncertainty in predicting the likelihood of rapid nutation growth due to onboard liquids. Solely analytical methods of prediction are …
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Adaptive Control of Thrusters to Account for Deficiencies in Actuator Effectiveness and Model Uncertainties
… and adaptive control laws for an over-actuated spacecraft system with 3 degrees of freedom (DoF) to mitigate the effects of actuator deficiencies and system uncertainties. Additionally, the nature of the system being over-actuated allows for particular actuator degradation and failure. For …
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Fault detection algorithms for spacecraft monitoring and environmental sensing
… there is a growing need for efficient spacecraft systems monitoring and space situational awareness to avoid service interruptions due to hazards such as space weather. Particularly for large constellations, satellites need greater autonomy to improve responsivity and reduce the load on …
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Natural and perturbed dynamics about Trojan bodies
This thesis analyses the dynamics of a massless spacecraft (or point mass) around an inhomogeneous Trojan body in a system composed of three primaries lying on a plane at the vertexes of an equilateral triangle, with their mutual positions fixed over the course of the motion. This configuration …
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On the identification and mitigation of life-limiting mechanisms of ionic liquid ion sources envisaged for propulsion of microspacecraft
… the development of ILIS for propulsion of microspacecraft and other industrial applications. Micropropulsion in particular has received considerable interest in recent years due to the increasing utility of and demand for small satellites and the services they provide. A passively-fed, porous …
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Spacecraft Systems Design for LuNaDrone: A Deployable Lunar Hopper
L'abstract è presente nell'allegato / the abstract is in the attachment
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Development of a model-based systems engineering architecture for an unmanned cargo spacecraft design
Unmanned Cargo Spacecraft (UCS) systems involve exceedingly complex systems engineering and design in order to implement. UCS typically include a vast range of subsystems – Command and Data Handling (C&DH), Attitude Determination and Control System (ADCS), Propulsion, Guidance, Navigation, and …