I am not going to defend Challenger.  IMO, it was more an issue with NASA than the shuttles design.<p>Still, the point is they did not need to wait over a year reusing launches from design constraints.  Instead, NASA simply did not need that many manned launches per year.<p>Now, I am not saying it was a great or even that good of a design.  It was simply a poor fit for what they used it for.  NASA would have been better off with either a much smaller shuttle that only sent crew up, or an unmanned system for hauling cargo.  Instead, they tried to do both which caused a lot of problems.