Understandably, some older experienced riders question the need for such systems, just as some senior surgeons have resisted the use of operating-room checklists—where could that missing hemostat be? These systems are ultimately a gift to motorists from the US space program. Centralized digital flight control was adopted just in time for the Apollo flights to the moon. The concept was next implemented on military aircraft, then in commercial flying, and further made to ease the special stability and control problems of Formula 1. From there, it has moved to autos, racing motorcycles beginning in 1990, and now, Harley-Davidson.