Space Shuttle Tiles

I’ve never mentioned this before – I really should do a biography at some point – but I have a B.Sci. in Ceramic Engineering, which is a specialty offshoot of materials science and engineering. Essentially, “ceramics” is considered anything that is non-metallic and non-organic; so glass, china, and silicon semiconductors are ceramic; metals and wood are not. (This is a broad definition. Geeks: don’t break my chops).

How did I get into this field, you may ask. Well, at the time I was starting at Rutgers, two of the hottest technologies around were “high-temperature” superconductors and Space Shuttle tiles. (For the record, I got into fiber optics and I’m now an engineer at OFS Photonics making specialty optical fiber.) We had a space shuttle tile in our ceramics lab and it was the most amazing stuff. We would put this cube of very light material into an oven at temperatures upward of 800C, remove it with a pair of tongs, and within a couple of seconds you could pick it up with your bare hand. Made almost entirely of silica (that is, sand), it could withstand temperatures up to 2000C, but because it was so porous, the tile dissipated heat very rapidly. (See here for a good explanation of the Space Shuttle tiles: High Temperature Reusable Surface Insulation Tiles.)

Speaking as somebody who has held a space shuttle tile in his hand, I can tell you two things: the tiles are very light and, as a ceramic, can be very brittle. Under compressive stresses, ceramics tend to be very strong, but if a stress is applied a certain way (say a shear stress at a corner) the material can break off. Also, the space shuttle tile is 90% air; a cubic foot of tile material weighs only 9 pounds. This is great for insulation or refractory applications, but if enough force is applied, there’s only the 10% silica structure to hold the tile together.

This concludes today’s tutorial – take it as you will.