STS-135 T-26 - How will we get to the moon and back?

The Mercury program only required the development of a capsule to attach to the top of an existing, functioning, missile design.  To get to the moon, a complete new system of components had to be developed and created from scratch.  The strategy to get to the moon and back comprised the Apollo Program.  There were lots of moving parts to the strategy.  Each step was perilous by itself, not to consider the odds of everything going right.

Saturn V being moved to the launch pad

1) Build a huge three stage rocket, called the Saturn V, that was taller than a than a football field is long, including the end zones.  It was to be four times as tall and 100 times heavier than Alan Shepard's Mercury Redstone.

2) Launch a combination of boosters, life support systems, reentry vehicle, and lunar landing craft into orbit.  The Lunar Excursion Module (LEM) was the piece that landed on the moon.  It would be left on the moon.  The Command Module (CM) was home for the trip each way and the reentry craft.  The Service Module (SM) contained all the life support and power systems, to be jettisoned just before reentry.  (CM and SM are CSM)

3) At the right time, fire the third stage and propel the set of pieces towards the moon.

CSM pointy part is CM, big cylinder is the SM

4) On the way to the moon, jettison the used third stage booster and extract the LEM from the storage compartment used for launch by disconnecting the CSM, spinning it around, and docking with the LEM.  Plenty of things could go wrong.

5) Make sure the course is accurate enough that it misses the moon by a precise amount, so the moon's gravity would pull the combined spacecraft around the back of the moon.  Then, at just the right time, fire a retro rocket to slow it all down so it stays in orbit around the moon.  Remember how many Rangers, missed.  The accuracy for this trip was far more critical.  A little off and it goes off into deep space or crashes into the moon.

Lunar Excursion Module - LEM

6) Get into the LEM, fire its rockets and use them to lower the LEM to the surface, hover, and land.  Take a walk, then fire a second rocket in the LEM at just the right time to meet back up with the SM in lunar orbit, and successfully dock with it.

7) Fire the SM rocket to make the trip back to earth.  Accuracy counts even more.  Too close the earth and it burns up in the atmosphere.  Too far and it skips off into deep space.

Each of the steps had many hazards.  Many were untested. While the Apollo was being built, we embarked on the Gemini Project to develop the technology, skills, and experience needed to succeed...

http://en.wikipedia.org/wiki/Apollo_program