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Full-Text Articles in Engineering
Operationally Responsive Spacecraft Using Electric Propulsion, Thomas C. Co
Operationally Responsive Spacecraft Using Electric Propulsion, Thomas C. Co
Theses and Dissertations
A desirable space asset is responsive and flexible to mission requirements, low-cost, and easy to acquire. Highly-efficient electric thrusters have been considered a viable technology to provide these characteristics; however, it has been plagued by limitations and challenges such that operational implementation has been severely limited. The technology is constantly improving, but even with current electric propulsion, a spacecraft is capable of maneuvering consistently and repeatedly in low-Earth orbit to provide a responsive and flexible system. This research develops the necessary algorithm and tools to demonstrate that EP systems can maneuver significantly in a timely fashion to overfly any target …
Empirical Characterization Of Unconstrained Tape Spring Deployment Dynamics, Daniel M. Williams
Empirical Characterization Of Unconstrained Tape Spring Deployment Dynamics, Daniel M. Williams
Theses and Dissertations
Satellite cost and mission capability are very sensitive to mass requirements. Mass or volume savings in one component will either lower total spacecraft mass, or provide greater margin for design error in other components. Solar arrays and antennas in particular are often driven by launch vehicle volume constraints instead of mission needs. Deployable structures provide more on-orbit area for both solar arrays and antennas, while occupying less space during launch. These structures therefore, help address these constraints and have been proven as efficient solutions for many years. Tape springs are one example in this category of structures which offer greater …
Methane Dual Expander Aerospike Nozzle Rocket Engine, Michael D. Moen
Methane Dual Expander Aerospike Nozzle Rocket Engine, Michael D. Moen
Theses and Dissertations
The Air Force Institute of Technology (AFIT), working to meet requirements set by the Air Force Research Laboratory's Next Generation Engine (NGE) initiative, is developing upper stage rocket models. The current path of investigation focuses on combining a dual expander cycle with an aerospike nozzle, or the Dual Expander Aerospike Nozzle (DEAN) using methane fuel. The design process will rely heavily on AFIT's previous work, which focused on the development of tools for and the optimization of a hydrogen/oxygen DEAN engine. The work outlined in this paper expands the existing research by substituting methane for hydrogen. The targets derived from …
Development Of A Star Tracker-Based Reference System For Accurate Attitude Determination Of A Simulated Spacecraft, Jorge G. Padro
Development Of A Star Tracker-Based Reference System For Accurate Attitude Determination Of A Simulated Spacecraft, Jorge G. Padro
Theses and Dissertations
The goal of this research effort is to investigate the analysis, design, integration, testing, and validation of a complete star tracker and star field simulator system concept for AFIT's satellite simulator, SimSat. Previous research has shown that while laboratory-based satellite simulators benefit from star trackers, the approach of designing the star field can contribute significant error if the star field is generated on a flat surface. To facilitate a star pattern that better represents a celestial sky, a partially hemispherical dome surface is suspended above SimSat and populated with a system of light emitting diodes of various intensities and angles …