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Are the Androids Dreaming Yet?

Review of Test Data Indicates Conservatism for Tile Penetration

• The existing SOFI on tile test data used to create Crater was reviewed along with STS-87 Southwest Research data
– Crater overpredicted penetration of tile coating significantly
• Initial penetration to described by normal velocity
• Varies with volume/mass of projectile (e.g., 200ft/sec for 3cu. In)
• Significant energy is required for the softer SOFI particle to penetrate the relatively hard tile coating
• Test results do show that it is possible at sufficient mass and velocity
• Conversely, once tile is penetrated SOFI can cause significant damage
• Minor variations in total energy (above penetration level) can cause significant tile damage
– Flight condition is significantly outside of test database
• Volume of ramp is 1920cu in vs 3 cu in for test

BOEING
2/21/03
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NASA Internal Slide

WHAT DO YOU UNDERSTAND FROM THE SLIDE?

Some images of the launch are shown on the right

Here is what you should have understood from the slide: tiles are really tough but if the foam dislodged from the fuel tank broke through the outer coating it would cause significant damage. The estimated speed of the foam hitting the tile was 640 times greater than anything previously tested. Worried?
Is this a proper understanding of the problem? You have the slide and the images. Take another look and think hard. If you want, you can check a video of a similar launch on YouTube to get a feel for the scale of things, but the still frames shown all the information you need to make your conclusion.

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