Saturn V Rocket  

The Apollo 11 astronauts were launched into space with a three-stage rocket- the Saturn V.  As fuel was used up in one section, it drops away and the next section takes over.  With less weight, the rocket does not need to be as large, also meaning that less fuel is needed.  The Third section is fired twice- once to get the Apollo 11 in earth’s orbit, and once to accelerate to escape it.