Mercury-Redstone 4 was the fourth mission in the Mercury-Redstone series and the second U.S. manned suborbital spaceflight. The mission was essentially a repeat of Alan Shepard’s Freedom 7 flight. So why was it necessary to launch another sub-orbital mission? Why not proceed with an orbital flight to match the Soviet Vostok 1? Among other things the U.S. needed more space experience to corroborate the “Man-in-Space” concept. Also the Redstone was the only booster NASA had that was approved for manned launches. The Atlas booster was available but not ready. Atlas was capable of putting a Mercury Capsule into orbit, but it had been launched three times with unmanned capsules, and it had exploded on 2 of the 3 attempts.
Over 52 years ago, in the early hours of May 5th, 1961 the US prepared to launch its first man into space. Three weeks earlier, the Soviet Union had sent Yuri Gagarin on an orbital mission. This was a suborbital mission planed to last only 15 minutes. For the moment that did not matter, the entire nation held its breath while Alan Shepard became America’s first man in space.
During 1962, NASA faced three major tasks: first the mode selection and its defense (covered in episodes 106-109), second keeping North American moving on the command and service modules (covered in episode 110) and third finding a contractor to develop the separate landing vehicle required by that approach. Which we will cover today in episode 111.
The Apollo contract specified a shirt-sleeve environment. For this reason, North American was told not to include in its design a hatch that opened by explosives, like Mercury’s. An accidentally blown hatch in space would cause an instant vacuum and certain death for an astronaunt not wearing his pressure suit.