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Accession Number N20120014466
Title STS-133 Space Shuttle External Tank Intertank Stringer Crack Investigation Stress Analysis.
Publication Date Apr 2012
Media Count 36p
Personal Author B. E. Steeve
Abstract The first attempt to launch the STS-133 Space Shuttle mission in the fall of 2010 was halted due to indications of a gaseous hydrogen leak at the External Tank ground umbilical carrier plate seal. Subsequent inspection of the external tank (figure 1) hardware and recorded video footage revealed that the foam insulation covering the forward end of the intertank near the liquid oxygen tank had cracked severely enough to have been cause for halting the launch attempt on its own (figure 2). An investigation into the cause of the insulation crack revealed that two adjacent hat-section sheet metal stringers (figure 3) had cracks up to nine inches long in the forward ends of the stringer flanges, or feet, near the fasteners that attach the stringer to the skin of the intertank (figure 4). A repair of those two stringers was implemented and the investigation effort widened to understand the root cause of the stringer cracks and to determine whether there was sufficient flight rationale to launch with the repairs and the other installed stringers.
Keywords Cracks
External tanks
Liquid oxygen
Space shuttle missions
Space shuttles

Source Agency National Aeronautics and Space Administration
NTIS Subject Category 84G - Unmanned Spacecraft
84C - Manned Spacecraft
Corporate Author National Aeronautics and Space Administration, Huntsville, AL. George C. Marshall Space Flight Center.
Document Type Conference proceedings
Title Note N/A
NTIS Issue Number 1307
Contract Number N/A

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