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 20 of 233 for “"Low Earth Orbit"”.
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Medical Constraints in Spaceflight: Venturing Beyond Low Earth Orbit
… model of medical care used in spaceflight in low-earth orbit to a model of medical care that will be conducive to exploration space missions. The intent of this project was to identify organizations that are doing research and development or have established products that will fulfill the …
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Observation of Low Earth Orbit Debris using GNSS Radar
… from small items of space debris are incredibly low and the detection of a desired weak GNSS signal in the presence of other strong signals is often problematic. We investigate cross-correlation behaviour when the Doppler offset between the desired and interfering signal is large and non-linear …
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Low Earth Orbit Spacecraft Slotting: Towards an Implementable Proposal
The growth in the number of proposed low Earth orbit (LEO) satellites is driven primarily by large commercial communications constellations. The launch of even half of the proposed satellites would result in an order-of-magnitude increase in active spacecraft traffic, with significant implications …
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Low Earth Orbit Stability Analysis Using Monte-Carlo Techniques
… This thesis focuses on MOCAT-MC- MIT’s Orbital Capacity Analysis Toolbox Monte Carlo. MOCATMC propagates individual space objects while accounting for various probabilistic factors common to LEO RSOs including mission failure, collision and space weather while open to new capabilities. …
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An analysis of low-earth-orbit-satellite communication systems
There is an ever increasing need for low-cost communication systems in the world. One such system, low-earth-orbit satellites, can provide store-and-forward, as opposed to real time, communication for many earth stations. The advantages and disadvantages of such a system is presented. Material …
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Autonomous materials for active erosion resistance in low-Earth orbit
Submission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2025-12-01
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HEXANE : architecting manned space exploration missions beyond low-earth orbit
… long-term designs for manned spaceflight beyond Earth orbit remain indefinite. Although progress has been made in plans for operations on orbit, the capabilities gap for manned spaceflight beyond orbit has grown. Gaining an understanding of the trade-offs inherent in future system architectures …
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Proliferated Low Earth Orbit (pLEO) Satellite Constellation Handover Cost Analysis
… for users. This is very true of proliferated Low Earth orbit (pLEO) satellite constellation networks in which both the satellite and the user are mobile with respect to each other. As satellites travel in their obits, they move into and out of ground users’ views every few minutes [4], and …
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The Impact of Low-Earth-Orbit Satellites on GNSS Ambiguity Resolution
In this thesis, the impact of low-earth-orbit (LEO) satellites on carrier phase ambiguity resolution is demonstrated through a global covariance simulation and a hardware in-the-loop simulation. Dedicated LEO constellations for GNSS are expected to become operational within the next few years and …
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On-Orbit Servicing System Architectures for Proliferated Low Earth Orbit Constellations
On-orbit servicing (OOS) presents new opportunities for refueling, inspection, repair, maintenance, and upgrade of spacecraft (s/c). OOS is a significant area of need for future space growth, enabled by the maturation of technology and the economic prospects. This congestion is leading s/c …
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Dynamics and Control of a Tensegrity System in Low-Earth Orbit
… looks at placing a tensegrity structure in orbit around the Earth. As a spacecraft's orbit is moved further away from the Earth, the strength of the Earth's gravity field lessens. Ideally, such a flexible structure would be placed far enough away from the Earth so that the gravity field …
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A variable-rate modulation and coding scheme for low earth orbit satellites
Low Earth Orbit (LEO) satellites are increasingly being used for a wide variety of communications applications. These satellites have to operate in widely varying channel conditions. These conditions are often significantly better than the 'worst case' situations that are experienced and thus a …
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Trajectory design for solar sailing from low-Earth orbit to the Moon
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 1992.
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Overhead channel power control in a low earth orbit satellite communication system
Thesis (M.Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1998.
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Attitude Dynamics of Debris Resulting From Upper Stage Fragmentation in Low Earth Orbit
… from the fragmentation of a spent upper stage in low Earth orbit (LEO).</p> <p>Up to now only whole objects of axisymmetric shape have been studied with the purpose of estimating their tumbling rates in LEO. Three shapes have been considered to be representative for the purpose of the study: a …
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INNER: interface-aware neighborhood routing in large-scale low-Earth-orbit satellite networks
Submission published under a 24 month embargo labeled 'U of I Access', the embargo will last until 2027-05-01
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Capacity provisioning, failure recovery and throughput analysis for low earth orbit satellite constellations
… we use a method of \cuts on a graph" to obtain lower bounds on capacity requirements and subsequently find algorithms for routing and failure recovery that meet these bounds. Finally, we quantify the benefits of path based restoration over that of link based restoration; specifically, we find …
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Utilization of ambient gas as a propellant for low earth orbit electric propulsion
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 1995.
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Quantifying technology infusion and policy impact on low earth orbit communication satellite constellations
… system, and presents the analysis results. The low earth orbit (LEO) communication satellite constellation system serves as the platform for carrying out the system trade space analysis. The system is reproduced in computer environment in the form of a multiple-input-output MATLAB model. The …
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