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Proceedings Paper

Diode laser analysis of the sealed enclosures of the Charters of Freedom
Author(s): Glen William Sachse; Glenn S. Diskin; Thomas A. Slate; George F. Tucker; Joseph C. Hickman; James R. Podolske; Margaret Kelly
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Paper Abstract

We report the application of diode laser spectroscopy to the non-intrusive measurement of water vapor and helium content within the enclosures of the Charters of Freedom that were sealed by NBS approximately 50 years ago. The instrument was adapted from the Diode Laser Hygrometer, developed through the NASA Global Tropospheric Experiment program to make open-path water vapor measurements outside the NASA DC-8 research aircraft. Operating in the 1.4-micron wavelength region, laser wavelength scans of water vapor absorption lines enabled the determination of the moisture level and the amount of helium relative to air within the Charters enclousres (an indicator of enclosure leaks). These measurements revealed that at least five of the seven Charters of Freedom enclosures had not leaked since they were sealed approximately 50 years ago. The measurements also revealed that water vapor within these enclosures ranged from 29 to 55% greater than anticipated.

Paper Details

Date Published: 23 September 2002
PDF: 11 pages
Proc. SPIE 4817, Diode Lasers and Applications in Atmospheric Sensing, (23 September 2002); doi: 10.1117/12.453764
Show Author Affiliations
Glen William Sachse, NASA Langley Research Ctr. (United States)
Glenn S. Diskin, NASA Langley Research Ctr. (United States)
Thomas A. Slate, Swales Aerospace (United States)
George F. Tucker, The Sage Colleges (United States)
Joseph C. Hickman, NASA Langley Research Ctr. (United States)
James R. Podolske, NASA Ames Research Ctr. (United States)
Margaret Kelly, National Archives and Records Administration (United States)


Published in SPIE Proceedings Vol. 4817:
Diode Lasers and Applications in Atmospheric Sensing
Alan Fried, Editor(s)

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