system
Given the following post, respond as if you're commenting on Reddit:
human
How did the astronauts take off the moon?

It seems like the launching of the rocket from the Earth is not an easy thing. Any little error or deviation can delay the launch.
But how the hell without any equipment, launch station, etc did they manage to leave the moon?
gpt
A rocket engine. But the trick is that the rocket stage that took off the moon only needed enough fuel to bring the Astronauts (and soil samples from the Moon) back to Lunar orbit, where the much more powerful command-service module (CSM) was waiting to bring them back to Earth. Also, the descent stage of the lunar lander acted as a sort of "launch station" and was left behind.

Also, it should be noted that there are many different types of rocket engines. The ones used to take off from Earth are very maintenance-intensive, because we can afford them like that. For example, they're powered by liquid oxygen and liquid hydrogen, which have to be stored so cold that they literally boil in the tanks and have to be replenished continuously during the countdown. 

The kind of engine used in the Lunar ascent stage uses hypergolic fuel. This basically means storing two different chemicals that ignite on contact, then making them come into contact on purpose - they don't require an external ignition source, which removes a possible point of failure. Much easier to operate, but much less powerful than a liquid oxygen/hydrogen engine - but that's fine, because gravity is much weaker on the Moon.