Apollo 1 fire due to poor priorities by management.
Challenger disaster due to meddling in design choices to keep military solid fuel rocketry vendors viable from a financial stand-point. Insufficient units were needed by the military alone to keep hot cast fuel stacked section production open. Congressional pressure was applied to use the military vendors rather than develop cryogenic liquid fueled booster designs. NASA management ignored an engineering based protest to delay that day’s launch.
Columbia disaster origin relates to an environmental based mandate to change a urethane insulation formulation—to eliminate chlorofluorocarbon 11 components of the application mixture. This change resulted in insulation voids which prevented proper adherence to the large fuel tank skin surface. Moisture condensation upon the underlying metal surface with subsequent freezing, lead to large chunks falling off in flight.
Did you know that there was another Shuttle already rolled out to the pad that could have been used to rescue the Columbia crew?
Management didn’t want to be bothered to look for damage after being told it was most likely there.