Michael Murphy, Burkhard Bilger, Scott Carpenter, Francis French, John Glenn, Cooper Gordon, Gus Grissom, Wally Schirra, Alan Shepard, John Paul Stapp, Dana Kilanowski, David Simons
In the 1950s and early '60s, a small band of high-altitude pioneers exposed themselves to the extreme forces of the space age long before NASA's acclaimed Mercury 7 would make headlines. Though largely forgotten today, balloonists were the first to venture into the frozen near-vacuum on the edge of our world, exploring the very limits of human physiology and human ingenuity in this lethal realm.