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High-Resolution Inspection of the Space Shuttle External Tank Spray-on-Foam Insulation (SOFI) using Focused Millimeter Waves at D-Band (150 GHz)Space Shuttle Columbia's catastrophic failure has been attributed to a piece of spray-on-foam insulation (SOFI) that was dislodged from the external tank and struck the leading edge of the left wing. A piece of SOFI was also dislodged in the recent Space Shuttle Discovery's flight. Clearly, there is a great and urgent need to inspect the external tank SOFI and other similar insulating structures (including the acreage heat tile) in a reliable and robust fashion. In the past two years, millimeter wave nondestructive testing methods, using both real and synthetic focusing techniques, have shown great potential for this purpose. Recently obtained real-focused images from several different and complex SOFI panels have demonstrated the utility of these methods as being viable, robust, repeatable, simple, portable and effective. D-band frequency range which covers a frequency spectrum of 110- 170 GHz is well-suited for this purpose given the nature of the foam which causes significant scattering at much higher frequencies. This paper presents the results of using continuous-wave (CW) reflectometry conducted on several typical and complex SOFI panes at 150 GHz.
Document ID
20060013651
Acquisition Source
Marshall Space Flight Center
Document Type
Conference Paper
Authors
Kharkovsky, S.
(Missouri Univ. Rolla, MO, United States)
Zoughi, R.
(Missouri Univ. Rolla, MO, United States)
Hepburn, F. L.
(NASA Marshall Space Flight Center Huntsville, AL, United States)
Date Acquired
August 23, 2013
Publication Date
January 1, 2006
Subject Category
Spacecraft Design, Testing And Performance
Meeting Information
Meeting: American Society of Nondestructive Testing 15th Annual Research Symposium
Location: Orlando, FL
Country: United States
Start Date: March 13, 2006
End Date: March 17, 2006
Funding Number(s)
CONTRACT_GRANT: NNM04AA15A
Distribution Limits
Public
Copyright
Other

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