Eli5.. how did they blast off from the moon to get back to earth?
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The moon is so much smaller and lighter than Earth that it takes much less powerful rockets to reach orbit around the moon than it does the Earth. If you watch an Apollo mission take off from the moon, you’ll notice a small explosion to decouple the landing module from the landing gear and engine that got it down to the surface, leaving just the pod containing the astronauts and a very tiny engine to carry them into orbit.
From there, they rendezvous with the pilot in the main module and climb back into that vessel with any science they brought. From there, that larger vessel can make the return journey to Earth.
Having a separate landing module was done so they could use at little fuel as possible to perform the actual landing because getting all that weight back up into orbit is the hard part.
They then reached escape velocity for the moon such that they could exit the moon’s influence going in the opposite direction than the moon travels around the Earth (called retrograde) to achieve what’s called a “free return trajectory” this was done with all missions to orbit, land, and flyby the moon because it saves fuel. From there, they just need to slow down enough to not burn up in the atmosphere, and then they can return to Earth.
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