[epicide]

It's the same reason we did a slingshot maneuver rather than just point a rocket straight at the moon: leverage.

Metaphorically, you use time as a fulcrum to exchange a larger total travel distance for not dealing with as much gravity head on.

If we want to go to Mars, it makes sense to establish a moon base that we can use to store fuel and other supplies. Rather than having to escape (as much of) Earth's gravitational field and then head to Mars immediately after, we can utilize what we've gradually built up on the moon.

[elsonrodriguez]

I was under the impression that the aero braking greatly reduces the amount of fuel required to land on mars vs the moon, and due to this the Saturn V had enough lift to put a crew on mars.

If Apollo-era hardware can get to mars, why rendezvous at the moon?