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Science & Tech

Spacewalking: Training

Chris Hadfield

Lesson time 17:31 min

Chris describes his personal experience training for spacewalking in an underwater simulation and emphasizes the importance of gaining confidence in maneuvering and monitoring the spacesuit.

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


The very first spacewalk was done by a guy named Alexey Leonov. And he just about died. He went out on the spacewalk. His suit inflated. It was way stiffer than anybody expected. He couldn't bend his arms. He couldn't bend at the waist. The airlock that they had hastily constructed, because it was during the days of the space race, was actually made of pressurized material. So it was almost like coming out of one of those bouncy castles. And he was outside on a spacewalk. He was only out for one big pass of Russia, just 10 minutes or something outside. But when he tried to get back in, none of their preparation had gotten him ready for what it was actually going to be like. And he just barely got back in. In fact, Alexey, who was a really good gymnast and a very fit man, he had to manually depressurize his spacesuit right down to the level where it could barely keep him alive, where he was risking the nitrogen boiling out of his blood and getting the bends just to make his suit flexible enough that he could somehow physically manhandle his way back inside, pull the airlock in, get the hatch closed, and accomplish our first spacewalk. We learned a lot from Alexey. And we also learned that we need to somehow prepare and simulate for spacewalking in a much more realistic manner than he did. And we thought, what's the most spacewalk-type environment that we have on Earth? It's underwater. It's like scuba diving. And so the very first American astronauts that were going to spacewalk, they actually went down to some of the Caribbean islands. So they had a lucky break to do their spacewalk training in the shallow water using some of the early scuba equipment to try and train and develop spacewalking techniques. But then they dug an underwater training facility at the Johnson Space Center in Houston, Texas. And ever since then, ever since Alexey first took a huge risk to try and figure it out, we've been training for spacewalks underwater. We build an entire piece of space hardware down there. In the early days, it was the Space Shuttle, because that's where all our spacewalks occurred from. But now there's a huge section of the International Space Station permanently underwater in one of the biggest swimming pools in the world just on the outskirts of Ellington Field by the Johnson Space Center. And that's where I spent hundreds and hundreds of hours underwater, days and days underwater, trying to learn how to operate a spacesuit, how to maneuver myself, how to think in three dimensions, but also how to invent spacewalking, how to develop all of the techniques. It's not so much like you're just going to class and learning how to do something. It's not like you just go to astronaut school and you get a certificate and now you're qualified. It's more you have to gain all these skills, but then you're part of the team that is applying those skills, since it's all so new, to invent new techniques to do things, so that you and your crew...

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.


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

Chris, you are such an inspiration to me. Your eloquent way of speaking about the most magical topic imaginable was sensational. There wasn't a single second that I wasn't listening! Thank you!!!!!

I love how Chris encouraged and inspired us, he opened my eyes to the possibilities of being part of the space exploration. I learn a ton about the tips and mentality to success from his experiences and that meant a lot to me. Thanks a lot Chris!!!

I learned what I am going to do to become an astronaut. I have learned what Chris had to do to become and complete his dream, and from this masterclass, now I can too.

Chris Hadfield ist ein sehr inspirierender Lehrmeister. Er wirkt sehr charismatisch und es macht einfach Spaß, ihm zuzuhören. Mir persönlich haben besonders die Lektionen über die Reise zum Mars und die mögliche Besiedlung des Marses gefallen.


Bernardo F.

It sounds like a tremendous challenge, both physical as well as mental. I learned scuba diving, the classes were about 1 hour, and some of them felt eternal while others seemed to pass in seconds. I can't even imagine being down there, or high in orbit doing that for several hours, as the course continues, my admination doesn't cease to increase! Great lesson, I'd loved to see more footage of the training, I don't know if it's because of confidentiality or just because they didn't add it, anyway, the description was more than enough.

A fellow student

At its upper most, how many people can the ISS hold if it really needed to?

William D.

We did not learn SQUAT from the Russians about EVA. It was the space race and they didn't tell the world anything other than look at how great Mother Russia was! We had to learn all that ourselves. Read the memoirs of Gene Cernan, Richard Gordon, Michael Collins and Buzz Aldrin. Underwater simulation wasn't used until the Gemini 12 mission. Regarding the round hatch and square astronaut. Why wasn't this addressed during design and fabrication of the hatch? This problem isn't new. The original LEM hatch was round and had to be made square to let the moonwalkers get out.

Maddie W.

I really enjoyed learning about some of the more obscure challenges in spacewalking, such as trying to fit your 'square suit' through the 'round hole' of the airlock. It gives me a lot of respect for the astronauts' ability to maintain that kind of physical and mental discipline for hours at a time and during hundreds of total hours of training. My favorite line was, "this is the place where you learn the ballet." Make sure to look up some videos of the Neutral Buoyancy Lab on YouTube or something; really cool to watch!

Steve H.

It was very helpful to view the process of getting into the spacesuit. It would have been nice to view some training underwater footage but I suspect that is classified.

Marc W.

Chris is an amazing guy. Quite accomplished. I'd have a beer with him. Sometime the lecture can seem a little preachy.

A fellow student

it was a great lesson! so many details and sadly it was sad to here that the astronaut that cris talked about had died

laura J.

How does each have enough energy to work toward working for hours and then expected to do the job, working, learning and testing. What happened after you were in the pool for hours, did they feel any muscle problems?

laura J.

I cannot open my pdf for the classes from Chris, maybe someone could advise as no problem with other instructors

Ugo A. D.

I really enjoyed this lesson and the context in which Chris describes the requirements for training for a spacewalk. Especially when he describes the part from exiting out of the airlock into the universe, you can almost sense his awe and appreciation for having the opportunity to see the universe up close. I wish I was his spacewalk partner. Good stuff.