Bringing Columbia Home: The Untold Story of a Lost Space Shuttle and Her Crew

by Michael D. Leinbach

Chief among the concerns was the intricate heatshield system completely covering the orbiter. The shuttles had aluminum skin, and when “naked,” they looked remarkably similar to conventional aircraft. However, aluminum has a relatively low melting point and cannot withstand the blazing temperatures of reentry. NASA’s ingenious heatshield for the shuttle consisted mostly of a system of silica tiles, which not only insulated the vehicle’s structure, but actually radiated heat away from the shuttle. The tiles were lightweight, porous, and crumbled easily. They covered the belly, the tail, and the maneuvering engine pods protruding from the aft end of the vehicle. The tiles could not be applied as a single unit or even a few large pieces, because the orbiter’s airframe had to flex during launch and reentry as it encountered air resistance. So, the tile system ended up being a mosaic of thousands of tiles, each approximately six inches square and each with a unique shape. Each relatively fragile tile was glued to a felt pad, which was itself glued directly onto the aluminum skin of the orbiter. This allowed for slight movement in the orbiter’s structure without damaging the tiles. Every tile was numbered so that it could be readily identified and placed in the appropriate spot on the orbiter. The tiles were not the only components of the orbiter’s heatshield. Some parts of the shuttle were exposed to more extreme heat than the tiles alone could withstand. The nose cap of the or...