Two trips, a decade apart, spanned the most exciting era in space history.

Of the original seven astronauts chosen by NASA in 1959, only one, Alan Shepard, made it to the moon. And he almost didn’t. More than two years after his pioneering Mercury-Redstone flight in May 1961, Shepard was in training to command the first two-man Gemini mission. Progress to the moon was planned in three steps: Mercury to prove that space travel was feasible, Gemini to demonstrate rendezvous and long-term spaceflight, and Apollo to go all the way. In 1963, Shepard was a fair bet to fly all three.