Science & Tech

Rockets: How Rockets Work

Chris Hadfield

Lesson time 20:41 min

Chris explains the functions of the basic parts of a rocket, the physics of launching one beyond the atmosphere, and how rocket design has evolved from mission to mission.

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Topics include: Fuel, Steering, and Something to Carry • Saturn V • Rocket Stages: The Space Shuttle • Multiple Stages: Saturn V • Reusable Rockets


So how does a rocket work, anyway? How is it that we get off the surface of the world? Let's just start with an airplane. We're all pretty familiar with how an airplane works. There's an engine inside. We carry fuel inside the fuselage. And the wings hold us up. The oxygen that we're going to burn in the motor is just coming from the atmosphere. So the air comes in the front of the motor here. It mixes with the fuel that we brought. And then it comes spewing out the back, pushes us along. And then the wings are just holding us up against gravity that's holding us down. But what do we do when we want to go this way? What do we need to change for a rocket to work? Well, let's choose a very simple rocket design, this one. It's simple but it will work. So the real purpose of a rocket, of course, is to take something up to space. So in this case we'll say it's this capsule on the top. So one of the key components of a rocket is the thing that you're carrying. But then you need fuel, just like in an airplane. So somewhere inside this, there's a fuel tank. But the big difference of a rocket is, you're going to get above the air. You're not going to be able to get the free oxygen out of the atmosphere that an airplane gets. So you're going to have to bring the oxygen with you in order to be able to generate the power that's going to push you away from the world. So inside every rocket there needs to be not only fuel but also oxygen. And so that's why so many, even the cartoon rockets like this one, they're all sort of bulbous shaped because they are in fact flying tanks, tanks of oxygen, tanks of fuel. We only need two more things. We have a thing to carry. We have the fuel and oxygen tanks. Then we need a place for the hot stuff to come out. And that's the back here. That's where the engine thrusts. And then we need some way to steer on the way up. And in this case we've got, even though it's a cartoon rocket, we've got these big aerodynamic fins that will allow us to steer. They're not going to work once we get up above the air. These will only help us steer when we're in the air. As soon as we're in the emptiness of space, you can wave your fins around all you want, but they're no longer going to have any air to push against, so you won't be able to point. So somehow you need to be able to actually control which way the exhaust is coming out so that you can continue to steer your rocket when you get up above the atmosphere. But that's essentially true of every single rocket-- something that carries, the fuel and oxygen supply, a way to steer, and where the hot stuff comes out. [ROCKET IGNITION] Let's look at one of the classic rockets, Saturn V. This is what took us to the moon. It looks like a really complicated, interesting, different kind of thing. It was huge. It was 360-odd feet tall, you know, 36, 37 stories tall, an amazing thing. But let's look at it the same as we did the cartoon rocket. It's got the thing t...

About the Instructor

Impossible things happen. At age nine, Chris Hadfield knew he wanted to go to space. He eventually went there three times, becoming a commander of the International Space Station. In his MasterClass, Chris teaches you what it takes to explore space and what the future holds for humans in the final frontier. Learn about the science of space travel, life as an astronaut, and how flying in space will forever change the way you think about living on Earth.

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Chris Hadfield

The former commander of the International Space Station teaches you the science of space exploration and what the future holds.

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