Date of Award

8-2010

Level of Access

Campus-Only Thesis

Degree Name

Master of Science (MS)

Department

Electrical and Computer Engineering

Advisor

Ali Abedi

Second Committee Member

Nuri Emanetoglu

Third Committee Member

Vincent Caccese

Abstract

Space exploration is a cornerstone of American engineering and science. With the pivotal first moon landing occurring over 40 years ago, NASA has focused on a new task of achieving extended space missions, requiring scientists to live and work on celestial bodies. This brings the need to develop the specifications of a suitable space habitat. One solution lies in perfecting inflatable low-mass structures and equipping them with the necessities to withstand the adverse conditions inherent to these environments.

This work focuses on the structural monitoring of an inflatable space habitat, more specifically, characterizing impacts on the surface of such a structure. Given many celestial objects have no atmosphere, they are not shielded from small space debris that would normally incinerate on earth, creating the need for these additional safeguards. This thesis explores an accelerometer based system to localize and scale an impact on the structure’s surface.

An inflatable testbed is setup with appropriately selected sensors and data collection hardware. Tailored for wireless sensor implementation, methodologies are developed that utilize the accelerometer array to accurately determine the location, and calculate the intensity of, an impacting object. Various approaches to the caveats of such a task are explored throughout. Finally, the resulting algorithms are tested and evaluated on the space habitat test structure, providing a working proof-of-concept for an accelerometer based wireless impact localization and scaling system.

Topics in wave theory, signal processing, and numerical optimization are explored. Both time based and amplitude based systems are derived after affirming the existence propagating surface waves on the inflatable structure. Waves are detected utilizing simple peak detection as well as frequency domain analysis via a continuous wavelet transform. Localization is achieved using a time difference of arrival scheme, and numerically computed using both a nonlinear and linear approach. Results from varying wave detection algorithms, as well as the two solution methods, are compared. Scaling is achieved using amplitude analysis. Various sensor properties are verified experimentally and exploited in the impact scaling software, allowing the determination of impact intensities. The results of all systems are illustrated, sources of error are explained, and suggestions for future development on a final space structure are projected.

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