Did foam down shuttle?

摘要

A large piece of polyurethane foam from an external fuel tank may have played a role in the 1 Feb Columbia shuttle disaster in which seven astronauts were killed. The need to eliminate the use of CFCs (chlorofluorocarbons) may also have been a factor, since foams made using the HCFC-141b replacement blowing agent have a thinner external skin than those created when CFCs are used; they also appear to suffer adhesion problems.