Apollo astronauts practiced every second of their mission, even planting the flag (above), many times, indoors, outdoors, in space suits, underwater, in planes, in centrifuges, in pools, in the ocean and anywhere else NASA saw fit. They were prepared for every contingency and trained for water planned landings as well as desert and jungle survival in case their capsule missed the ocean and hit land. They learned geology, how to withstand g-forces, maneuver in low- and zero-gravity conditions, and how to drive electric rovers and land the lunar module.

Here are some of the most memorable photos of the rigorous Apollo astronaut training from NASA's image archive.

Above:

The Apollo 14 flight crew practices planting the flag during a lunar walk simulation.