How Rockets Work | Universe Today

Written by Tega Jessa

How do rockets work? We see them in cartoons and television but rarely do we hear about the actual mechanics that make rockets our primary ride to outer space. Rockets, regardless of their type, all function on the same basic principle: they burn some type of fuel to create heat which is used to heat air that is directed out the bottom of the rocket. This is called thrust. Thrust is what makes rockets work. Rockets differ depending on the type of propulsion method used.

The most simple type of rocket is the solid fuel rocket that uses a solid fuel, or grain, an ignition device and a nozzle. There are different ways to arrange the fuel in the combustion chamber. One way that is commonly used is to line the chamber with the grain. (Another is to simply have it in the middle.) In both methods, the burnt fuel heats the air in the combustion chamber to create an exhaust that is expelled through the nozzle to generate the rocket's specific impulse so it can fly.

Liquid fuel rockets use liquid oxygen or hydrogen as the source of propulsion. Their configuration is a bit more complicated. The pressure tank stores the fuel that is delivered to the combustion chamber via pipes and valves. The fuel is normally mixed with an oxidizer to burn easier. The heated liquid has now become a gas that creates the thrust for the liquid fuel rocket.

There are new types of rockets that are in development: the ion rocket uses magnets and an electric current to convert a gas into plasma. The repulsion of charges is used to expel plasma to produce thrust. The hybrid rocket uses a combination of liquid and solid fuel. The liquid fuel acts as an oxidizer when mixed with the solid fuel. This type of rocket is supposed to be more efficient than both liquid and solid rockets and have better control.

Regardless of their design all rockets have to create thrust to work. Unlike most aircraft they can't rely on lift and atmospheric pressure differences to stay in the air. They need the sustained expulsion of hot gases to fly.

If you enjoyed this article, there are others on the Universe Today site you might also want to read. One is about ion engines and another is about nuclear engines.

There are also great resources on the web to further your understanding of rockets. The NASA websites are always a good source of information. The HowStuffWorks site also has a great explanation of the process.

You'll also like to listen to episode 100 of Astronomy Cast.It talks about rockets in depth.

Filed under: Astronomy

Tags: hybrid rocket, liquid fuel rocket, rocket, rocket engine, solid rocket, thrust