Global ETD Search
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Showing 1 to 15 of 15 for “"Low-Thrust Propulsion"”.
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Small-Body and Heliophysics Missions using Hybrid Low-Thrust Propulsion
… of increasingly efficient and powerful propulsion systems. However, all of these systems, from the earliest chemical engines to modern electric thrusters, require propellant, thereby reducing the mass budget available for a payload. By harnessing the momentum of reflected photons of …
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Formation of RAAN-Spread CubeSat Constellations Utilizing Onboard Low-Thrust Propulsion
… occur within a timeframe and distance that allows for adequate capture of the horizontal wave vector. Receivers used in radio occultation have been successfully used on CubeSats. A CubeSat constellation of satellites in the same orbital plane with varying right ascension of the ascending node …
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Optimal pursuit/evasion spacecraft trajectories in the hill reference frame
… central body and each spacecraft uses continuous low-thrust propulsion. The thrust-pointing direction is the control for each spacecraft. Each vehicle has a finite specific impulse and therefore the mass of each vehicle decreases as propellant is consumed. Optimal closed-loop controllers were also …
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Space logistics network optimization with embedded propulsion technology selection
Establishing long-term human presence beyond low Earth-orbit will require cooperative use of emerging technologies, such as low-thrust solar electric propulsion, along with existing space exploration technologies. Trajectory analysis plays a key role in deciding the costs of using different …
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The orbital dynamics of advanced planetary observation systems
… than any other proposed system. Various low-thrust propulsion technologies are considered to enable the Taranis orbits, with electric propulsion found to be the most beneficial following mission analysis. Design of constellations for high-latitude remote sensing is also conducted which …
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Asteroid hazard mitigation: deflection models and mission analysis
… for nuclear interceptor, kinetic impactor, low-thrust propulsion, mass driver, solar collector and gravity tug are developed and their efficiency is assessed for a complete set of different types of hazardous celestial objects. A multi-criteria optimization is then used to construct a set of …
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Natural and perturbed dynamics about Trojan bodies
… inhomogeneities of the asteroid are negligible. Low-thrust propulsion perturbations are incorporated into this model. The possibility to determine the range of validity of each model using an application of a Weak Stability Boundary (WSB) theory, a relatively novel approach to dynamics for …
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Optimal strategies for selecting from multiple asteroid interception targets
… to an asteroid interception problem using low-thrust propulsion and solved through a combination of particle swarm optimization (PSO) and a commercial non-linear programming (NLP) solver SNOPT (Sparse Nonlinear OPTimizer). The problem considers an intercepting vehicle and three bodies of …
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Continuous Low-Thrust Trajectory Optimization: Techniques and Applications
… mission feasibility during mission design. High-thrust trajectory optimization problems are typically formulated as discrete optimization problems and are numerically well-behaved. Low-thrust systems, on the other hand, operate for significant periods of the mission time. As a result, the …
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Solar Sailing Adaptive Control Around the Earth-Moon Lagrange Point L4 for Stellar Observations
… trajectory is initially designed using low-thrust propulsion in a nonlinear optimal control problem.</p> <p>We further transition solar sailing periodic orbits to a higher-fidelity ephemeris model to account for actual celestial distances and planes of motion, as opposed to the CR3BP and …
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Low thrust augmented periodic orbits in the two- and three-body problems
Continuous low thrust propulsion can add considerable utility to spacecraft dynamics by enabling rich new families of thrust augmented orbits. With the aim of enabling such orbits for small, low-cost spacecraft with limited on-board sensing, new families of non-Keplerian orbits are generated in the …
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Technology for the Solution of Hybrid Optimal Control Problems in Astronautics
… approximating spacecraft trajectories that use low-thrust propulsion. Two new shapes are developed for the solution of time-free and time-fixed rendezvous problems respectively. The shape-based trajectories are compared to ""exact"" solutions and shown to be effective in determining near-optimal …
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Analysis, fabrication and testing of a MEMS-based micropropulsion system
… industry are driving the development of low-thrust propulsion systems. These may be needed for fine attitude control, or to reduce the mass of the propulsion system through the use of small lightweight components. The nozzle converts the stored energy in a pressurized gas into kinetic …
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Orbital Maneuvers and Interplanetary Trajectory Design via Reinforcement Learning
… learning (RL) to the design and optimization of low-thrust spacecraft trajectories, with an emphasis on autonomy, adaptability, and robustness in the presence of system uncertainties and unmodeled perturbations. Classical approaches to low-thrust trajectory design are predominantly grounded in …
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Automated global optimization of low-energy trajectories using a hybrid optimal control framework
… less fuel, thus gaining the moniker of low-energy transfers. Typically, these transfers are constructed by analyzing intersections of these dynamical structures at certain planes of interest in the form of Poincaré surfaces of section. Initial guesses gained from these maps are then used …