Apollo 11 got off the Moon by firing the Lunar Module’s ascent engine, which launched the astronauts from the surface and left the descent stage behind. The ascent stage then rendezvoused and docked with the Command Module in lunar orbit before the crew headed back to Earth.

Quick Scoop

Here’s the simple version:

  1. Armstrong and Aldrin were in the Lunar Module, Eagle. The module had two parts: a descent stage that stayed on the Moon, and an ascent stage that carried the crew back up.
  1. They ignited the ascent-stage engine. That rocket was enough to lift the lighter upper half of Eagle off the Moon’s surface in the Moon’s low gravity.
  1. They left the descent stage behind. Once the ascent stage rose away, it separated from the part used for landing.
  1. They met up with Michael Collins in orbit. Eagle docked with the Command Module, Columbia, and the astronauts transferred back inside.
  1. Then they returned to Earth. After leaving lunar orbit, Columbia reentered Earth’s atmosphere and splashed down in the Pacific Ocean.

Why this worked

The key was that Apollo 11 did not need to launch a full spacecraft from the Moon. It only had to launch the small, lightweight ascent stage , which made the trip possible with a much smaller engine.

If you want, I can also turn this into a one-paragraph explain-it- like-I’m-12 version or a step-by-step timeline.