By Topic

Application of the NASA risk assessment tool to the evaluation of the Space Shuttle external tank re-welding process

Sign In

Cookies must be enabled to login.After enabling cookies , please use refresh or reload or ctrl+f5 on the browser for the login options.

Formats Non-Member Member
$31 $13
Learn how you can qualify for the best price for this item!
Become an IEEE Member or Subscribe to
IEEE Xplore for exclusive pricing!
close button

puzzle piece

IEEE membership options for an individual and IEEE Xplore subscriptions for an organization offer the most affordable access to essential journal articles, conference papers, standards, eBooks, and eLearning courses.

Learn more about:

IEEE membership

IEEE Xplore subscriptions

2 Author(s)
Mulvihill, R.J. ; Hernandez Eng. Inc., Huntsville, AL, USA ; Safie, F.M.

The current Space Shuttle external tank design is called the super light weight tank (SLWT). A weight reduction of approximately 30% was achieved relative to the prior design called the light weight tank (LWT). The new NASA risk assessment tool, the quantitative risk assessment system (QRAS), was used to compare the risk of the two designs. The comparison includes consideration of the apparent reduction of the design safety factor for SLWT welds when a weld repair is required. The risk models for the structural failure accident scenario include five initiating events (IEs): (1) liquid oxygen (LO2) tank component failure; (2) liquid hydrogen (LH2) tank component failure; (3) LO2 tank weld failure; (4) LH2 tank weld failure; and (5) intertank failure. Although the risk results for the LH2 and LO2 tank welds for IEs 2 and 4 are higher for the SLWT vs. the LWT, the reverse is true for tank components IEs 1, 3 and 5. The SLWT has a slightly lower risk of structural failure. The impact of this difference is not significant to the total risk when the other six scenarios are also included

Published in:

Reliability and Maintainability Symposium, 2000. Proceedings. Annual

Date of Conference:

2000