Launch system designers base their designs on the best data available—but sometimes, the best data are just good estimates. True measurements of the launch environment can only be obtained in flight, and that's hardly an option at the design stage. The inherent risks of this design approach were driven home on one occasion when a faulty part caused an anomaly in a vintage launch system. The anomaly was only discovered when a part of the rocket part fell back to the launch site, landing on top of a parked car belonging to a member of the launch team! The failure most likely occurred because the actual aerodynamic loads encountered in flight were higher than what the original designers had calculated using the tools available to them at the time. The piece had probably failed on multiple flights and may have caused other unsolved problems; however, because the empty stages always fell into the ocean and were never inspected after launch, no one knew there was a problem with this part.