Science & Tech

Spaceships: Capsule Design

Chris Hadfield

Lesson time 19:42 min

Learn the virtues and drawbacks of using the capsule model for human transport to space as Chris analyzes the designs of the Apollo, Gemini, Lunar Lander, and Soyuz.

Students give MasterClass an average rating of 4.7 out of 5 stars

Topics include: "Gemini • Apollo • Lunar Lander Design • Capsules: Disposable Reentry Modules"


A spaceship is essentially a little sample of the earth taken off the planet, a little bubble of life away from the natural place where we all began. You need to bring along the things that keep you alive. You need to bring air, oxygen, something to breathe. You need water. We can't go very long without water. You need to control the temperature so it doesn't get too hot, too cold. Eventually you're going to need food. You need something that can process the body's waste, the waste gases that I breathe and all the rest of the waste the body produces. A spaceship needs to provide all of those normal earthly things, but away from the planet. In order to make a machine that can keep at least one astronaut alive way out in the thermal vacuum of space is extremely complicated. If we were willing to have astronauts die all the time, it gets way simpler. But if we actually want to have the astronaut live, then you have to try and think of everything. And on top of the thermal requirements and the air-pressure requirements and the water and the waste and everything, you're also weightless. Nothing is going to behave the same on the spaceship as it does back on earth. The fluids won't go to the bottom of the tank. Will the astronaut be able to swallow and breathe? What will happen the blood-pressure regulation? How do you do everything when heat doesn't rise, when there's no gravity? It's a whole new world of problems, and it was one that took several decades to get to the state that we're at right now. So what do you actually need to keep a crew alive and healthy and productive inside a spaceship? If we just look at an airplane of course, this little early jet could just barely take us out of the bubble where we can naturally live. It could go high enough where the air was so thin that we couldn't just fly along with the canopy open like this. We had to have a way, in this early F-86, of being able to pressurize the cockpit, to have a little bubble of life way up in the sky in an environment where otherwise life couldn't exist. And sort of that's like the initial early stages of a spaceship, taking a little bubble that provides just the minimum that, in this case, the pilot needs in order to safely survive somewhere away from the cradle of earth itself. But to go higher, this little bubble needs to get more and more complicated and more and more capable. One of the earliest spaceships was the Gemini capsule. It looked a lot like the Mercury capsule. You can tell this is a Gemini because it's got the twins, two seats, Gemini. But this was one of the very first space ships, as simple as we could make it, but a big tradeoff between all of the things we needed. Essentially it's a little cockpit. It has air pressure inside. And it's got this whole section here for systems to keep you alive, to take your breath and process it through some carbon dioxide removal system so that you can continue to breathe oxygen. It's got a thermal regulat...

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.

Featured Masterclass Instructor

Chris Hadfield

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

Explore the Class
Sign Up