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Thrust And Performance Study Of Micro Pulsed Plasma, Jeremy J. Selstrom
Thrust And Performance Study Of Micro Pulsed Plasma, Jeremy J. Selstrom
Theses and Dissertations
This research is focused on several areas of the μPPT performance. An important idea studied is the effect of lifetime use on the performance. The thruster is fired for a simulated lifetime of use to see if there is an impact on the thrust of the thruster later in life. Also vital is the efficiency of the thruster. A μPPT performing at max efficiency will ionize all ablated material; however, we know that not to be the case. In this research the effort is made to collect these non-ionized particles in order to measure their mass post-test. With this collected …
Attitude Model Of A Reaction Wheel/Fixed Thruster Based Satellite Using Telemetry Data, Jason E. Smith
Attitude Model Of A Reaction Wheel/Fixed Thruster Based Satellite Using Telemetry Data, Jason E. Smith
Theses and Dissertations
Attitude determination of satellites is normally the job of inertial instruments, such as gyroscopes, or through sensing instruments, such as star trackers or Global Positioning Satellites (GPS). Satellite health monitoring systems watch and determine if the satellite deviates from its normal operating attitude orientation. Knowing the orientation of a satellite is essential in being able to control it in order to complete the satellite's designated mission. While there are a multitude of ways to determine a satellite's orientation, very little research has been done on determining if the attitude of a satellite can be determined directly from telemetry data of …
A Numerical Analysis For Passive Attitude Stabilization Using A Tethered Balloon On A Gravity Gradient Satellite, Ernest Matias Maramba
A Numerical Analysis For Passive Attitude Stabilization Using A Tethered Balloon On A Gravity Gradient Satellite, Ernest Matias Maramba
Theses and Dissertations
This research effort analyzes the fundamental dynamics governing a satellite with a gravity gradient boom and a tethered balloon. Satellites that use gravity gradient booms for passive attitude control are characterized by undamped pitch oscillations and no roll control. The tethered balloon acts as a high drag device that accounts for the most drag on the satellite system. By attaching a drag device, the system resists rolling movements while also damping oscillations. This could potentially be a cost effective method for increasing satellite stabilization. The goal of this research is to model the dynamics and determine the feasibility of a …
Sub-Optimal Control Of Rigid Spacecraft Reorientation Using Three Momentum Wheels, Gregory W. Schultz
Sub-Optimal Control Of Rigid Spacecraft Reorientation Using Three Momentum Wheels, Gregory W. Schultz
Theses and Dissertations
This thesis addresses sub-optimal employment of 3 momentum wheels for large angle reorientation of rigid spacecraft with minimal induced spacecraft motion during maneuvers. In addition to development of general theory for 3 wheel vehicles, simulation results for a vehicle using momentum wheels for secondary attitude control (GPS Block IIR) are compared to results for a vehicle using them for primary attitude control (the Hubble Space Telescope), to demonstrate practical applications and limitations. While the control laws were developed assuming no external perturbing torques on the vehicle, reorientation scenarios were run both in a torque free environment as well as an …
Satellite Attitude Determination Using Linear Combination Of Models, Martin S. Chin
Satellite Attitude Determination Using Linear Combination Of Models, Martin S. Chin
Theses and Dissertations
In satellite analysis, it is often necessary to determine the attitude of a satellite from a two dimensional image of the satellite. This thesis describes work performed to determine the attitude of a satellite relative to a reference position. The attitude is described in terms of the scaling, rotation and translation of the reference that will result in a pose that can be projected to form the image of interest. The techniques used are based on finding coefficients for the linear combination of basis images and decomposition of a composite transformation matrix. The methods were initially modeled in Mathematica and …