Thrust: Rocket Engines


Explore how rocket engines generate thrust.


Hi, my name is Ashley, and I'm an Explainer at The National Air and Space's "How Things Fly" gallery. And today we're going to learn about rocket engines.

Over here, I have a model of the Saturn V rocket, which was used to launch the Apollo astronauts in 1969. Now, behind me I have a real F-1 engine. Each F-1 engine was capable of producing one and half million pounds of thrust.

Now, this model of the Saturn V rocket has five F-1 engines. So, calculating that you have about seven and half million pounds of thrust produced by this rocket. As you can see, a tremendous amount of thrust is needed that can't be obtained from a propeller or jet engine. In addition, propeller and jet engines don't work in the vacuum of space. Rockets are special though. They carry their own oxygen or other oxidizers on board with them.

So now let's learn about how a rocket engine actually works. So we have the fuel and we have the oxidizers. Now, they ignite inside the combustion chamber, and all of that is let out as exhaust coming out of each one of the five F-1 rocket engines. Now inside of the engine we have a pressure difference because of that our rocket is going to shoot upwards and according to Newton's "Third Law of Motion", for every reaction there has to be an opposite equal reaction which is the exhaust moving downwards.

Now there are three main types of rockets: Liquid, solid, and gas. So today we're going to launch off our own gas rocket. Here I have a cartridge that's filled with compressed carbon dioxide gas. I'm gonna poke a small hole on this end of the cartridge, so that all my carbon dioxide gas is gonna spew out this way. So if my gas is spewing out that way, which way should my rocket go? That way right? So let's see what happens. Now according to NASA's standards, we're gonna have a countdown.

Starting from 5...4...3...2...1.

[cartridge takes off]


[rod whirring]

And that's how rockets generate thrust.

Categories: Propulsion Rockets