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Master's Projects

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Now showing 1 - 10 of 102
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Low-Thrust Trajectory Optimization Tool to Assess Options for Near-Earth Asteroid Deflection

2007-12-01 , Stahl, Benjamin Andrew

In the past decade, the scientific community has become more interested in Near Earth Objects (NEOs) and the threat they pose to existence of life on this planet. The recent trend in NEO deflection technique research has been toward “slow push” techniques in order to absolve the need for sending nuclear weapons into space. A software tool was developed to assist in design and performance testing of various low-thrust deflection methods. The tool features an n-body high fidelity long term orbit propagator that allows for deflection mechanism forces to be directly applied through the equations of motion. The propagator utilizes DE405 ephemeris data for the acting bodies and was validated through comparison with JPL’s HORIZONS database. A hybrid optimization algorithm featuring a genetic algorithm global search and a conjugate direction local search was also developed to optimize the thrust direction versus time for a given deflection technique. The optimizer is applicable for many different missions and objectives, and is tested with several missions designed to maximize NEO close approach miss distance.

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Unsuccessful Plans and What Might Have Been: Wal-Mart and the Redevelopment of the Old Avondale Mall Site on Memorial Drive in DeKalb Co., GA

2007-07 , Berry, K. Lynn

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Mayor's Park: Analysis of an Urban Park as a Neighborhood Reconnection Tool

2007-05 , Singer, Samantha

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Blueprint: Piedmont Heights

2007 , Chernock, Jason , Harper, Jennifer , Keating, Xandon , Lewandowski, Steve , Nelson, Jennifer Indech , Nelson, Melanie , Paget-Seekins, Laurel , Stephens, Alexa , Trudell, Talya , Zuehlke, Zai , Conschafter, Stephen , Habeeb, Dana , Hwang, Kyu , Kim, Young , Qin, Sharon , Page, Jerry , Sung, Ada

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Hypersonic Entry Aeroshell Shape Optimization

2007-12-01 , Theisinger, John E.

Several different approaches to shape optimization are explored to identify hypersonic aeroshell shapes that will increase landed mass capability by maximizing drag-area for a specified lift-to-drag ratio. The most basic approach manipulates standard parameters associated with analytic aeroshell shapes like the sphere-cone and ellipsled. More general approaches manipulate the control points of a spline curve or surface. The parametric polynomial formulations of the Bezier and B-spline curves and surfaces are employed due to their desirable properties in shape design. Hypersonic aerodynamic analyses are carried out using Newtonian flow theory panel methods. An integrated optimization environment is created, and a variety of optimization methods are applied. In addition to a lift-to-drag ratio constraint, size constraints are imposed on the aeroshell, as determined by payload volume requirements and launch vehicle shroud size restrictions. Static stability and center-of gravity placement required to achieve hypersonic trim are also considered during optimization. An example case is presented based on the aeroshell for the Mars Science Laboratory mission.

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Tagging for TV: Design Document

2007-05 , Lausier, Annie

In recent years, television has developed from a limited set of shows constrained by a fixed timeslot into a veritable viewer’s choice of channels, shows, and times. In addition, we have seen the rise of the complex episodic series that encourages replay. Meanwhile, the Internet has grown into a media-rich, customizable experience for users who have become familiar with the concept of tagging items with keywords to foster the organization of a network. Broadcast has begun to merge with broadband in many forms, but viewers still have little to help them navigate through a show. This project, Tagging for TV, brings tagging from the Internet to television as a social, viewer-generated means of organizing data.

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Kitchen Incubators: An Economic Development Opportunity for Atlanta, GA

2007-05 , Granier, Miguel

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Space Shuttle Solid Rocket Booster Control Limitations Due to Failure of an Hydraulic Power Unit

2007-11-21 , Kranzusch, Kara M.

The Space Shuttle solid rocket boosters (SRBs) each have two nozzle actuators to provide thrust vector control (TVC). Two hydraulic power units (HPUs) provide hydraulic pressure to drive the actuators and are capable of driving both gimbals simultaneously at 5º/s. One HPU, however, is only designed to drive both gimbals simultaneously at a combined rate of 6º/s. Reduced gimbal rate capability due to failure of an HPU can limit the gimbal’s ability to keep up with commands and the development of large command-position deltas could cause loss of control of the actuator. Due to SRB thrust authority during the Shuttle’s first stage, loss of control of an SRB TVC could result in loss of the vehicle. To study the effect of a failed HPU during nominal ascent profiles, an SRB actuator was modeled in SIMULINK and the gimbal drive rate was limited to simulate the failure. The maximum resulting command-position deltas were calculated to determine control limitations. The required gimbal rate summation limit to cause loss of control of an SRB actuator in response to an HPU failure during nominal ascent demands is also estimated. Through this analysis, large margins are demonstrated against this failure scenario. The availability and feasibility of an operational response are discussed.

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Murmur : kinetic relief sculpture, multi-sensory display, listening machine

2007-05 , Rydarowski, Aimee

Today, increasingly varied modes of data representation, coupled with accessible technological resources, have democratized the field of information visualization and opened computing to new user groups. This environment has created a critical mass of consumer-creators who serve up information baked, sautéed, flambéed, stuffed, roasted, pureed, boiled, braised, steamed and flash fried to audiences with discerning pallets. By thoughtfully varying data representation, we can increase opportunities for information to be thoroughly digested. Murmur is a multi-sensory display, an interactive kinetic relief sculpture and listening machine. The design intention is to balance these elements so they enhance one another and are still compelling when considered separately. The aural information that Murmur presently displays is representative of the combination of environmental as well as self-produced sounds picked up by its sensors.

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Statistical Reconstruction of Mars Entry, Descent, and Landing Trajectories and Atmospheric Profiles

2007-04-27 , Christian, John Allen

Accurate post-flight reconstruction of a vehicle’s trajectory during entry into a planetary atmosphere can produce a wide array of valuable information. The data collected through the reconstruction of entry, descent, and landing (EDL) system performance enables the quantification of performance margins for future systems. Beyond the engineering knowledge gained through trajectory reconstruction, the results may also be used by planetary scientists to generate an accurate atmospheric profile. A computer tool was developed to facilitate the rapid analysis of data gathered during entry. Emphasis was placed on making the tool flexible and capable of easily incorporating different types of data. These data are used to provide an accurate reconstruction through the use of an Extended Kalman Filter (EKF). In its present form, the filter propagates the mean state forward using a three degree-of-freedom dynamic model and is capable of handling data from accelerometers and altimeters. The tool is validated against previous trajectory and atmosphere reconstructions that were performed for the Mars Pathfinder mission.

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