Undesired manufactured or in-service produced anomalies in the form of voids in the SOFI and unbonds in the heat tiles can significantly reduce their designed effectiveness. Additionally, unbonds in the heat tiles may cause their complete separation from the fuselage exposing it to extreme heat. Millimeter wave NDT methods are viable candidate for life-cycle inspection of the SOFI and the acreage heat tiles of the Space Shuttle fleet. The results of these investigations described in this paper clearly showed the utility of these methods for detecting localized anomalies in thick SOFI and acreage heat tiles. These methods are fast and robust and the systems used to produce these images are small, real-time and provide a significant amount of useful information about the nature of an anomaly (e.g., size, location, etc.) without the need for complex image processing. This investigation is currently ongoing and additional results will be provided in the final paper.

Meeting Name

IEEE Instrumentation and Measurement Technology Conference (2005: May 16-19, Ottawa, Ontario, Canada)


Electrical and Computer Engineering

Keywords and Phrases

External Tank; Far-Field; Heat Tiles; Insulating Foam; Millimeter Waves; Near-Field; Nondestructive Testing; Space Shuttle

International Standard Serial Number (ISSN)


Document Type

Article - Conference proceedings

Document Version

Final Version

File Type





© 2005 Institute of Electrical and Electronics Engineers (IEEE), All rights reserved.

Publication Date

01 May 2005