A few comments from an interested observer of NASA upon reading the report of the commission looking into the Columbia disaster, "Sweat the small stuff." NASA, like most of us seems to grow inattentive when things are going well, but there are some things that you just cannot mess around with and two of them are rockets and nuclear reactors. When you're out on the edge of technology and the costs of failure are so high, you cannot treat things as routine. I've always thought that the reason nuclear power has not flourished in the U.S. was that it was treated as just another construction project, subject to union laxness and administrative hubris. I would say that not everybody, regardless of training and brains, should be allowed to work on shuttle missions or in the control room of a nuclear power plant. They should not be putting in overtime, and they should not be told to quit worrying. These are the kind of things you want people to worry about and check every detail, whether is seems to be an "acceptable risk" or not. Having things hit the leading edge of a shuttle's heat shield is one of those things. The U. S. Navy was the first to build nuclear powered submarines. They didn't have nuclear disasters because, I think, (1) the program was run by Admiral Rickover and (2) when you're in a sub, it's probably hard to forget all that water on the other side of the walls.