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Full-Text Articles in Engineering
Satellite Propulsion Spectral Signature Detection And Analysis For Space Situational Awareness Using Small Telescopes, Pamela L. Wheeler
Satellite Propulsion Spectral Signature Detection And Analysis For Space Situational Awareness Using Small Telescopes, Pamela L. Wheeler
Theses and Dissertations
Safe satellite operations are of utmost importance. Maintaining precise orbital maintenance places stringent performance requirements on current propulsion systems, which are often electric propulsion systems. Electron temperature is a commonly used diagnostic to determine the performance of a Hall thruster, and recent work has correlated near infrared (NIR) spectral measurements of ionization lines of xenon and krypton to electron temperature measurements. In the research herein, appropriate line spectra ratios are identified for each propellant type when used with remote space-to-ground observations. NIR plume emissions were used to characterize a 600 Watt Hall thruster for a variety of observation angles and …
Analysis Of An Experimental Space Debris Removal Mission, Krista L.L. Roth
Analysis Of An Experimental Space Debris Removal Mission, Krista L.L. Roth
Theses and Dissertations
Encountering space debris is an ever-increasing problem in space exploration and exploitation, especially in Low Earth Orbit. While many space-faring governing bodies have attempted to control the orbital lifetime post mission completion of satellites and rocker bodies, objects already in orbit pose a danger to future mission planning. Currently, governments and academic institutions are working to develop missions to remove space debris; however, the proposed missions are typically costly primary missions. This research proposes an alternative to use an upper stage rocket, to be called a chaser, already launching a primary mission near the desired debris as a host for …
Investigating Analytical And Numerical Methods To Predict Satellite Orbits Using Two-Line Element Sets, Adam T. Rich
Investigating Analytical And Numerical Methods To Predict Satellite Orbits Using Two-Line Element Sets, Adam T. Rich
Theses and Dissertations
As Low Earth Orbit (LEO) contains an ever-increasing number of objects, the prediction of future object positions must be precise in order to avoid collisions. Object positions are distributed in two-line element (TLE) sets and are generated using the analytical propagator known as Simplified General Perturbations 4 (SGP4). However, a numerical integrator called Special Perturbations (SP) provides an alternative approach to TLE generation and propagation. In this thesis, TLE accuracy was determined with both models, and the length of time that a single element set can provide valid information was also established. With two-line element sets as data, comparisons were …
Military Space Mission Design And Analysis In A Multi-Body Environment: An Investigation Of High-Altitude Orbits As Alternative Transfer Paths, Parking Orbits For Reconstitution, And Unconventional Mission Orbits, John N. Brick
Theses and Dissertations
High-altitude satellite trajectories are analyzed in the Earth-Moon circular restricted three-body problem. The equations of motion for this dynamical model possess no known closed-form analytical solution; therefore, numerical methods are employed. To gain insight into the dynamics of high-altitude trajectories in this multi-body dynamical environment, periapsis Poincare' maps are generated at particular values of the Jacobi Constant. These maps are employed as visual aids to generate initial guesses for orbital transfers and to determine the predictability of the long term behavior of a spacecraft's trajectory. Results of the current investigation demonstrate that high-altitude transfers may be performed for comparable, and …
The Impact Of Atmospheric Fluctuations On Optimal Boost Glide Hypersonic Vehicle Dynamics, Melissa A. Dunkel
The Impact Of Atmospheric Fluctuations On Optimal Boost Glide Hypersonic Vehicle Dynamics, Melissa A. Dunkel
Theses and Dissertations
A project under the management of Air Force Research Laboratory has begun development of a six degree of freedom model for use in hypersonic vehicle development and application. One area of interest is the perturbation of vehicle behavior based on atmospheric fluctuations – how the performance of the vehicle changes with respect to “hot”, “cold” and standard day conditions. The method developed to fill this need uses real-world data from the Global Forecast System to create a “hot” and “cold” day dataset to compare with the standard day model. The key parameter is atmospheric density, a value calculated over a …