Part of the problem with the Space Shuttle was a double whammy, on the one hand it had no emergency capabilities in the event the shuttle itself was compromised. This is what caused the Columbia disaster as . On the other hand is the US procurement guidelines for large military/space projects that required the jobs building the shuttle to be spread out around the US. As a result the boosters had to be built in stages and put together later, rather than in one singular unit. It was this that then resulted in the Challenger disaster as the connecting ring to the booster rocket segments was compromised by the unusually low temperatures the night before launch. The worst bit about the Challenger disaster though was the fact that the dangers of the booster construction had actually been known since 1971 and not addressed until after the disaster.