On October 14, 1947, flying the Bell X-1 rocket plane, Chuck Yeager burst through the mythical sound barrier at mach 1.0, to become the first man to fly faster than the speed of sound. Yeager's epic flight was the culmination of hours of work and flying time by a group of dedicated aviation pioneers, and it marked the beginning of flight testing as we know it. Who were these men? What were the aeronautical hurdles they cleared to usher in the space...