Toward the end of January 1967, it was revealed that Lunar Module 1 would not reach the Cape in February, as expected. This meant, the moon landing might be delayed because the lander was not ready. But the mission planners could not wait for the Apollo engineers to iron out all the problems. They had to plan for a landing in 1969 and hope that the hardware would catch up with them.
At various stages of lunar module design, mockup reviews were conducted to demonstrate progress and identify weaknesses. These inspections were formal occasions, with a board composed of NASA and contractor officials and presided over by a chairman from the Apollo office in Houston.
The Lunar Lander originally had two docking hatches, one at the top center of the cabin and another in the forward position, or nose, of the vehicle, with a tunnel in each location to permit astronauts to crawl from one pressurized vehicle to the other…
Since the lunar module would fly only in space (earth orbit and lunar vicinity), the designers could ignore the aerodynamic streamlining demanded by earth’s atmosphere and build the first true manned spacecraft, designed solely for operating in the spatial vacuum.
Max Faget’s position was that considering the difficulty of the job, if each mission was successful half the time, it would be well worth the effort. But Gilruth thought that was too low. He want a 90% mission success ratio and a 99% ratio for Astronaut safety. Walt Williams who was currently running the Mercury program believed that astronaut safety needed to be limited to only 1 failure in a million which was 99.9999%.
…From the information they gathered on the existing technical problems, Disher and Tischler concluded that prospects were only one in ten that Apollo would land on the moon before the end of the decade….