The sound barrier, with two broken ribs

Chuck Yeager was dropped from the belly of a B-29 over the Mojave and flew past the speed of sound, having broken two ribs falling off a horse two nights earlier and told nobody.

He could not reach far enough to close the hatch, so a friend cut him a length of broom handle to lever it shut. The flight was classified and the news did not get out for eight months; the barrier turned out not to be a barrier so much as a patch of very bad handling on the way through.