On October 14, 1947, Captain Chuck Yeager climbed into the Bell X-1 “Glamorous Glennis” at Rogers Dry Lake, California. The X-1 was shaped like a .50-caliber bullet because bullets were known to be stable at supersonic speeds. Yeager had broken two ribs two days earlier in a horseback riding accident; he was in so much pain that his flight engineer, Jack Ridley, sawed off a piece of broomstick so Yeager could close the hatch with his left hand. Air-launched from a B-29 at 20,000 feet, Yeager fired the rocket engine and reached Mach 1.06 at 42,000 feet. The Mach needle jumped from 0.965 to 1.06. The flight lasted 14 minutes. Yeager later said the real barrier “wasn’t in the sky but in our knowledge and experience of supersonic flight.”