Browsing by Department "Aerospace Engineering"
Now showing items 120 of 130

A comparison of range and rangerate based GRACE gravity field solutions
(20110713)In the generation of the standard GRACE gravity fields, the KBand Ranging (KBR) system data is used in its rangerate mode. Because time derivatives attenuate the gravity signal relative to the data noise at the lower ... 
A comprehensive numerical model of Io's chemicallyreacting sublimationdriven atmosphere and its interaction with the Jovian plasma torus
(20120629)Io has one of the most dynamic atmospheres in the solar system due in part to an orbital resonance with Europa and Ganymede that causes intense tidal heating and volcanism. The volcanism serves to create a myriad of volcanic ... 
A critical evaluation of modern lowthrust, feedbackdriven spacecraft control laws
(20121206)Lowthrust spacecraft trajectory optimization is often a difficult and timeconsuming process. One alternative is to instead use a closedloop, feedbackdriven control law, which calculates the control using knowledge of ... 
A dynamical systems theory analysis of Coulomb spacecraft formations
(20130611)Coulomb forces acting between close flying charged spacecraft provide near zero propellant relative motion control, albeit with added nonlinear coupling and limited controllability. This novel concept has numerous potential ... 
A new method to incorporate internal energy into a discrete velocity Monte Carlo Boltzmann Equation solver
(20110920)A new method has been developed to incorporate particles with internal structure into the framework of the Variance Reduction method [17] for solving the discrete velocity Boltzmann Equation. Internal structure in the ... 
A reusable command and data handling system for university CubeSat missions
(20140115)A Command and Data Handling (C&DH) system is being developed as part of a series of CubeSat missions being built at The University of Texas at Austin’s Texas Spacecraft Laboratory (TSL). With concurrent development of four ... 
A selfcontained guidance and targeting algorithm for spacecraft applications
(20121002)The development of a selfcontained, onboard, fully autonomous trajectory guidance tool for spacecraft is presented. To be considered completely autonomous requires the capability to both identify an appropriate startup ... 
A star tracker design for CubeSats
(20120612)This research outlines a lowcost, lowpower, arcminute accurate star tracker that is designed for use on a CubeSat. The device is being developed at the University of Texas at Austin for use on two different 3unit CubeSat ... 
A study of timevarying geopotential models for ICESat precision orbit determination
(20120611)Precision orbit determination (POD) plays a vital role in the success of spaceborne laser altimetry missions, such as ICESat (Ice, Cloud, and Land Elevation Satellite). Although current ICESat POD processing standards are ... 
A tabu search methodology for spacecraft tour trajectory optimization
(20141205)A spacecraft tour trajectory is a trajectory in which a spacecraft visits a number of objects in sequence. The target objects may consist of satellites, moons, planets or any other body in orbit, and the spacecraft may ... 
Acoustic waveforms produced by a laboratory scale supersonic jet
(20140905)The spatial evolution of acoustic waveforms produced by a Mach 3 jet are investigated using both 1/4 inch and 1/8 inch pressure field microphones located along rays emanating from the post potential core where the peak ... 
Acoustics from highspeed jets with crackle
(20130606)A scaling model based on an effective Gol'dberg number is proposed for predicting the presence of cumulative nonlinear distortions in the acoustic waveforms produced by highspeed jets. Two acoustic length scales, the shock ... 
Adaptation, gyroree stabilization, and smooth angular velocity observers for attitude tracking control applications
(20140908)This dissertation addresses the problem of rigidbody attitude tracking control under three scenarios of high relevance to many aerospace guidance and control applications: adaptive attitudetracking control law development ... 
Adaptive and convergent methods for large eddy simulation of turbulent combustion
(20150316)In the recent past, LES methodology has emerged as a viable tool for modeling turbulent combustion. LES computes the large scale mixing process accurately, thereby providing a better starting point for smallscale models ... 
Adaptive control for doubleintegrator class systems in the absence of velocity feedback
(20121206)This work considers formulation of new classes of adaptive controllers for doubleintegrator type systems where the underlying system parameters are uncertain and the complete statevector is not available for feedback. ... 
Adaptive estimation and control algorithms for certain classes of largescale sensor and actuator uncertainties
(20120629)This dissertation considers the general problem of controlling dynamic systems subject to largescale sensor and actuator uncertainties. The assumption is made that the uncertainty is limited to either pure rotation (i.e. ... 
Adaptive finite element simulation of flow and transport applications on parallel computers
(20110823)Not available 
Alignment filtering of ICESat flight data
(20121101)ICESat consisted of the Geoscience Laser Altimeter System (GLAS) and a commercial spacecraft bus. The stability of the GLAS to bus alignment was unknown and significant for GLAS pointing. Pointing control was performed by ... 
An analytical approach to computing step sizes for finitedifference derivatives
(20120629)Finitedifference methods for computing the derivative of a function with respect to an independent variable require knowledge of the perturbation step size for that variable. Although rules of thumb exist for determining ... 
An assessment of the GPS L5 signal based on multiple vendor receivers
(20120221)The L5 signal of the Global Positioning System (GPS) is becoming available on an increasing number of Block IIF satellites. As the third civilian signal, L5 is superior in signal design to the L1 C/A and L2C civilian ...