Reply #13: What I find interesting about the tile design is this...

[Javaman]

Every system on the shuttle has 3 additional back ups. Why then is there only one way of protecting the shuttle during re-entry?

During the days of the apollo program a heat shield was used to protect the capsule upon re-entry. With all the technology and geegaws invented since the apollo days, one would think that they could come up with something a hell of a lot better than frigging tiles!

I had an idea a few years ago, but it would add a lot of weight to the shuttle so, I thought it a bad idea. However now I don't think it's so bad and with modern tech I'm sure they can figure out a lighter way.

Why doesn't NASA use that apollo tech on the shuttle. Still use the tiles but under the tiles, especially the wing and nose sections, place a layer of the heat shield resistant material that was used during 60's. I'm sure at this point they could figure out some sort of thinner material or a spray on version of that stuff.

Pardon my ignorance in all of this, I'm neither a rocket scientist or play one on TV. It's just something that begs to be explored.