Date of Award

5-2016

Level of Access Assigned by Author

Campus-Only Thesis

Degree Name

Master of Science (MS)

Department

Electrical and Computer Engineering

Advisor

Ali Abedi

Second Committee Member

John Vetelino

Third Committee Member

Vincent Caccese

Abstract

Micrometeoroid and orbital debris (MMODs) are becoming a major threat to spacecraft and habitats in Low Earth Orbit (LEO). Orbital MMODs travel at hypervelocities ranging from 7-10 km/s in LEO [1], and have the potential to impact and penetrate orbiting spacecraft. These impacts can leak oxygen, heat, or fuel, thus compromising the safety of the astronauts and possibly impeding upon spacecraft mission objectives. The Wireless Leak Detector (WLD) is a proof-of-concept, automated device that is capable of detecting and localizing leaks accurately and efficiently.

Leaks in pressurized structures have been shown to emit airborne ultrasonic acoustics from the source of the leak. WLD uses arrays of ultrasonic sensors and onboard processing to listen for and record leak signatures. Leak locations are estimated using a combination of angle of arrival (AoA) from time difference of arrival (TDOA), Kalman filtering, and a novel tree-search algorithm.

Prototypes of the system were constructed and tested in labs at the University of Maine. WLD was designed and constructed to accommodate NASA safety guidelines for the International Space Station (ISS). The system is currently scheduled to launch to the ISS in Summer/Fall 2016, where it will collect valuable data on leak localization in microgravity environments. Background theory, leak localization methods, system design, and experimental test results are presented.

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