Mock-up of Apollo Program LEM (Lunar Excursion Module) at Grumman.
To meet the goal originally set by President Kennedy, of landing a man on the Moon and safely returning him to the Earth by the end of the decade, NASA and its contractors had a tremendous pressure to use every available moment to prepare for that event. There comes a point where decisions have to be made to stop designing and start manufacturing. So it was with the LEM in the last week of March, 1964. Officials from the NASA Manned Space Center arrived at Grumman Aircraft Engineering Corporation for a three day inspection of the current design of the LEM. The goal was to arrive at a "freeze" of the main design elements of the lunar module, so that manufacturing could begin shortly. Once the engineers had decided the final design acceptance or directions, the press was allowed to enter the building and get a look at the future of manned lunar landers. For those of you familiar with the final appearance of the LEM, you can see there are still some design elements to adjust, but the major components and functions have been determined at that point.
Now let's take a look back to some interesting phases of the LEM design, using models for the previous years.
Lunar capsule concept, 1961. The multiple leg concept is well established.
Lunar Excursion Module design, 1963. There's too much heavy window in the design, which needs reduction in weight.The hatch will not permit a spacesuited astronaut with a big pack to get through.
LEM design, 1964 before final redesign. It's almost there, but the Hatch still needs to conform to allow the passage of a spacesuit with a large square backpack. The windows are in final mode.