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Proceedings Paper

Development of detectability limits for on-orbit inspection of space shuttle wing leading edge
Author(s): Ryan A. Stephan; David Geoffrey Johnson; A. J. Mastropietro
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Paper Abstract

At the conclusion of the Columbia Accident Investigation, one of the recommendations of the Columbia Accident Investigation Board (CAIB) was that NASA develop and implement an inspection plan for the Reinforced Carbon-Carbon (RCC) system components. To address these issues, a group of scientists and engineers at NASA Langley Research Center proposed the use of an IR camera to inspect the RCC. Any crack in an RCC panel changes the thermal resistance of the material in the direction perpendicular to the crack. The change in thermal resistance can be made visible by introducing a heat flow across the crack and using an IR camera to image the resulting surface temperature distribution. The temperature difference across the crack depends on the change in the thermal resistance, the length of the crack, the local thermal gradient, and the rate of radiation exchange with the environment. The current paper describes how the authors derived the minimum thermal gradient detectability limits for a through crack in an RCC panel. This paper will also show, through the use of a transient, 3-dimensional, finite element model, that these minimum gradients naturally exist on-orbit. The results from the finite element model showed that there exists sufficient thermal gradient to detect a crack on 96% of the RCC leading edge.

Paper Details

Date Published: 28 March 2005
PDF: 12 pages
Proc. SPIE 5782, Thermosense XXVII, (28 March 2005); doi: 10.1117/12.605735
Show Author Affiliations
Ryan A. Stephan, NASA Langley Research Ctr. (United States)
David Geoffrey Johnson, NASA Langley Research Ctr. (United States)
A. J. Mastropietro, NASA Goddard Space Flight Ctr. (United States)

Published in SPIE Proceedings Vol. 5782:
Thermosense XXVII
G. Raymond Peacock; Douglas D. Burleigh; Jonathan J. Miles, Editor(s)

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