For decades, mankind has used rockets to travel into space. But one rocket alone is not powerful enough to launch into space. In fact, the rockets we hear about are actually several rockets stacked on top of one another: these pieces are called stages.
A rocket needs two to three stages, which are different rockets put together, in order to launch. If you tried to go into space with only one rocket, gravity would pull it down back to Earth.
Rockets are powered by gas. A rocket has to go 40 times faster than a jumbo jet to launch into space. Some shuttles are also equipped with parachutes and brakes and need a lot of fuel to run.
There are many amazing facts about rockets—their use of stages is just one.
[Source: 100 Things You Should Know About Space]