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Accession Number N20120014458
Title Stringer Bending Test Helps Diagnose and Prevent Cracks in the Space Shuttle's External Tank.
Publication Date Apr 2012
Media Count 8p
Personal Author G. R. Swanson J. B. Saxon R. J. Wingate W. P. Ondocsin
Abstract Space Shuttle Discovery's last mission, STS-133, was scheduled to launch on November 5, 2010. Just hours before liftoff, a hydrogen leak at an umbilical connection scrubbed the launch attempt. After the scrub, further inspection revealed a large crack in the foam insulation covering the External Tank, ET-137. Video replay of the launch attempt confirmed the crack first appeared as cryogenic propellants were being loaded into the ET. When the cracked foam was removed, technicians found the underlying stringer had two 9-inch-long cracks. Further inspection revealed a total of 5 of the 108 ET stringers had cracked. NASA and Lockheed Martin immediately launched an aggressive campaign to understand the cracks and repair the stringers in ET-137, targeting February 2011 as the new launch date for STS-133. Responsibilities for the various aspects of the investigation were widely distributed among NASA centers and organizations. This paper will focus on lab testing at Marshall Space Flight Center (MSFC) in Huntsville, Alabama that was intended to replicate the stringer failure and gauge the effect of proposed countermeasures.
Keywords Bend tests
Cryogenic rocket propellants
External tanks
Failure analysis
Finite element method
Oxygen-hydrocarbon rocket engines
Space shuttles
Structural failure
Umbilical connectors

Source Agency National Aeronautics and Space Administration
NTIS Subject Category 84C - Manned Spacecraft
94J - Nondestructive Testing
81C - Fuel & Propellant Tanks
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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