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 9 of 9 for “"Orbit Transfers"”.
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Optimal orbit transfers for satellite formation flying applications
This dissertation focused on trajectory optimization problems arising from the application of satellite formation flying, and obtained three major results. First, the dissertation proposed an algorithm for finding a multi-impulse, fuel-optimal trajectory, based on relative motion dynamics, and the …
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Optimization of relative orbit transfers via particle swarm and primer vector theory
… the amount of fuel required for impulsive transfers between periodic orbits in the relative motion problem. Relative orbit elements are used in order to create the solution vectors for the particle swarm, and the Clohessy-Wiltshire-Hill equations are used to define the motion of the …
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Spacecraft trajectory design utilizing resonance orbits in a hybrid optimal control framework
… inherent stability and instability of certain orbits as a means of fuel efficient transfers. Traditionally, work on these types of trajectories has taken a very “hands on” approach from the astrodynamicist, i.e. requiring intuition and fine tweaking of parameters. This work details preliminary …
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Modeling of Hall thruster lifetime and erosion mechanisms
… suited for missions such as station-keeping and orbit transfers. However, uncertainty about thruster lifetime has impeded the device's widespread integration as mission designers want a propulsion system guaranteed to last the entire mission duration. Furthermore, recent interest in applying the …
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Trajectory design in the spatial circular restricted three-body problem exploiting higher-dimensional Poincare maps
… about Jupiter, and the search for periodic orbits in the vicinity of the primary bodies in the spatial problem. Because current strategies to represent higher-dimensional maps, generally, lead to a loss of information, new approaches to represent all information contained in …
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Improved collocation methods with application to direct trajectory optimization
… and used to solve minimum-time, Earth-moon orbit transfers. These collocation methods are based on a family of modified Gaussian quadrature rules. This family of rules includes the basic trapezoid and Simpson quadrature rules. The collocation schemes derived from the trapezoid and Simpson …
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Optimal Electrodynamic Tether Phasing and Orbit-Raising Maneuvers
… tether (EDT) performing phasing and orbit-raising maneuvers. An EDT is a conductive tether on the order of 20 km in length and uses a Lorentz force to provide propellantless thrust. We develop the optimal equations of motion using Pontryagin's Minimum Principle. We find numerical …
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Technology for the Solution of Hybrid Optimal Control Problems in Astronautics
… are specialized to solve several types of orbit transfer problems. The resulting solutions are less exact than a conventional direct or indirect method would yield but are shown to in fact be quite good. Then a ""shape-based"" method is developed for rapidly approximating spacecraft …
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Optimization-Based Guidance for Satellite Relative Motion
… to two (or more) satellites in nearly identical orbits. We examine control design for relative configurations on the scale of meters (for the purposes of proximity operations) as well as on the scale of tens of kilometers (representative of science gathering missions). Realistic control design …