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Proceedings Paper

Fiber optic microsensor hydrogen leak detection system on Aerospike X-33
Author(s): Alex A. Kazemi; John W. Goepp; David B. Larson; Mark E. Wuestling
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Paper Abstract

Commercial and military launch vehicles are designed to use cryogenic hydrogen as the main propellant, which is very volatile, extremely flammable, and highly explosive. Current detection system uses Teflon transfer tubes at small number of vehicle location through which gas samples are drawn and stream analyzed by a mass spectrometer. A concern with this approach is the high cost of the system. Also, the current system does not provide leak location and is not in real time. This system is very complex and cumbersome for production and ground support measurement personnel. This paper describes the successful test of a multipoint fiber optic hydrogen microsensors system on the Linear Aerospike X-33 rocket engine at NASA's Stennis Flight Center. The system consisted of a reversible chemical interaction causing a change in reflective of a thin film of coated Palladium. The sensor using a passive element consisting of chemically reactive microcoatings deposited on the surface of a glass microlens, which is then bonded to an optical fiber. The system uses a multiplexing technique with a fiber optic driver-receiver consisting of a modulated LED source that is launched into the sensor, and photodiode detector that synchronously measures the reflected signal. The system incorporates a microprocessor to perform the data analysis and storage, as well as trending and set alarm function. The paper illustrates the sensor design and performance data under field deployment conditions.

Paper Details

Date Published: 2 October 2007
PDF: 12 pages
Proc. SPIE 6758, Photonics in the Transportation Industry: Auto to Aerospace, 675807 (2 October 2007); doi: 10.1117/12.731475
Show Author Affiliations
Alex A. Kazemi, The Boeing Co. (United States)
John W. Goepp, The Boeing Co. (United States)
David B. Larson, NexGen Research Corp. (United States)
Mark E. Wuestling, NexGen Research Corp. (United States)

Published in SPIE Proceedings Vol. 6758:
Photonics in the Transportation Industry: Auto to Aerospace
Alex A. Kazemi; Christopher S. Baldwin, Editor(s)

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