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Science & Tech

Rockets: The Price of Exploration

Chris Hadfield

Lesson time 18:18 min

Rockets and spaceflight are dangerous by definition. Learn how astronauts manage their fears and cope with tragedy as Chris had to do after the loss of a friend in the Columbia Space Shuttle mission.

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.


MAN: Challenger, go with throttle up. MAN 2: Roger, go with throttle up. MAN 3: This shuttle mission will launch-- My God. There has been an explosion. MAN 4: --2,900 feet per second, altitude nine nautical miles, down range distance 7 nautical miles. MAN 3: This is not standard. This is not something that is planned, of course. I can see a solid rocket booster has broken away from shuttle Challenger. That's what you're looking at in the middle of your screen. I cannot see the shuttle itself. I don't know if it's able to continue on one rocket booster. If it's able to jettison that rocket booster, it will be able to return to the Kennedy Space Center. Perhaps the shuttle engines are not enough to power the shuttle back down. By definition, rockets are dangerous. The real question is, can you make it safe enough and have you made your trade-offs good enough that you think you can trust it either to launch a robot or, in this case, to launch people? And on the space shuttle, it was pretty safe. I flew it twice. But it also killed two crews. We had two horrific accidents with this space shuttle. Both of them essentially caused by trade-offs of the rocket design. In Challenger in 1986, during launch, instead of all of this solid rocket fuel burning properly and coming out the back, you can look at this model and see that it's made of individual segments. They were shipped on rail cars from Promontory, Utah all the way down to Florida and assembled there. And because they're assembled down in Florida, there's just seals in there. And they launched on an extremely cold day. One of those seals failed, and instead of all of the hot explosion coming out the back, a little bit of it started leaking out the side and it cut the strut to the big external tank. And as soon as that strut got cut, the whole vehicle came apart and killed the crew on board. During the Columbia accident in 2003, a piece of the insulating foam of this external tank popped off, came down and hit the wing right here. We needed this insulating foam because the liquid oxygen and liquid hydrogen inside is so cold, we don't want ice to form on the tank and ice to hit the shuttle. But it's just foam. And every single flight, little bits of foam would come off. But in this case, a piece of foam about the size of a briefcase popped off, hit the left wing and knocked a great big hole in the front of the wing of Columbia. And so when it tried to come back into the atmosphere at the end of the flight, all of that heat of the friction and pressure from the atmosphere, instead of being taken up by the protective Thermo Shield of the shuttle, it got funneled down into the wing and it started melting all the internal structure of the wing. The left wing failed, the vehicle came apart and killed that crew. So there are trade-offs to building rockets. You try and make it as safe as you can, but it's never going to be super safe. MAN 1: All right, uh. Got a little problem on 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.


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

I know Chris Ferguson, but never want to make him tell the same stories he probably gts asked by everyone. This was fun, and Mr. Hadfield brings a lot of passion to the field.

I really like it and the reason I got this lesson is because I want to be an astronaut it sounds so much fun and maybe I will even learn a lot

Thanks for all your hard work for space exploration and education. I have learnt a lot from this master class.

He is Amazing! Aside from the knowledge, the most significant take from this is his well-build way of being! In love with what he does, humble, curios, gracious, and wise! He is inspiring!


Tobias E.

A lot of people doesn't share this philosophy and just live their lifes with minimum risk. That's what you normally get to see, during growing up, especially from older adults. But this question "Which risks are worth taking them", I guess it's so important to ask yourself, to live a good life. You have so few opportunities, if you are not willingly to take risks. But if taking risks is an option, there are so many things you can do in and with your life. I will definitily try to ask myself this question more often. This lesson really makes me think... It's one of the best, I'd say. Very beautiful.

Bernardo F.

I must admit I wasn't expecting a lesson like this one, but it's beautiful... I mean, hearing from someone who risked his life not just for self-fulfillment, but for helping all humanity progress it's just amazing! My father has told me when he was younger and watched all launches, and the tragedies that happened to the Space Shuttle, but Chris is right, you don't quit only because you failed, you can put both achievements and fails in a balance, and surely the former will be heavier. Sadly, sometimes we take those fails as a stop sign, it's true, we don't want to fail, specially when there are lives in risk.

A fellow student

There is no way to describe this lesson and the effect it will have on my life. He talked about the dangers that go into the risk of rockets and spaceflight. We understand the dangers and we are wiling to take that risk in order to know what we will find on the other side. My grandparents were pioneers who walked across the plains in order to live the religious life they had chosen. Many died on the way and the plains are littered with the graves of men, women, and children who gave their lives for what they believed in. As difficult as it was to cross the plains, for women to give birth in such harsh conditions, they would not have given up their quest.


I had to think about this. But I believe this lesson is appropriate when you understand that his target audience (the ones really learning from this) are kids. Kids that lack experience which comes from back breaking, devastating life lessons. For the older generation (or even boomer like myself) who will never make it to space and are here for other reasons, we know that there is no choice but to get back up, dust yourself off, and move forward again. But for many younger adults or kids, the first truly heartbreaking loss might feel like the end of the world to them.

mirjam V.

I think it's an important lesson; it tells me that even after such tragic losses ( forgotten Apollo 1) can improve the safety and security of space flight, because you never want to let it happen again. That is difficult you need strength to think like this that's not for all of us., but an astronaut has to think like this. I understand, I lost my husband 9 years ago but I had to go on, you just cannot stop. I think this is a very valuable lesson. Thanks Chris.

William D.

I don't see the purpose of this lecture in a class on Space Exploration. Yes, space is a dangerous place. OK, but we don't have to belabor the point. Chris talks about trade offs in design but doesn't mention the trade offs made on the shuttle due to budgetary concerns. Once the solids lit off there were NO abort options until they burned out and were jettisoned. Remember the words of Apollo 1 Astronaut Gus Grissom, "the exploration of space is worth the risk of human life." Now lets get back to work.

Mário Filipe P.

How to cope with loss. How to come out of it with a stronger sense of purpose. How to face and overcome our fears. How to sustain a positive outlook even when everything seems to be falling apart. I'm still half way through Chris class, but this will probably be my favourite lesson of them all, just because how deeply this one connects with me. Chris remarkable wisdom and life experience lead to some of the most valuable advices I've ever heard of. I will definitely keep some of those words with me for the rest of my life. Thank you so much Chris for sharing it with us. - I'm deeply sorry for the loss of your friend Commander Rick Husband and the whole crew of the Columbia Space Shuttle back in 2003, may their souls rest in peace.

Jung H.

wow, I'm impressed with his ability to cope and explain tragedies. How he gave meaning to his colleagues/friends lost lives and his choice of accepting the risk for the greatest purpose. The fear definition is mindblowing: "Things are not scary, they are just things. It's your reaction to them." "The best antidote against fear is competence." He nailed there. He is such a wonderful motivational speaker because you can see/feel that he speaks from experience, from personal growth, it is real and not something he read in books. I love his humanity and humbleness considering his success to speak about the hardest things like human errors that killed men on a mission. This episode alone can be a motivational speech in any area of life and profession.

Jeremy P.

This lesson is not something to watch once or twice, but often during your life. It's something to take with you no matter what happens. To "continue" is key. Use the lessons from yesterday to do better today. Thank you Chris Hadfield

Mary S.

Such wise words of wisdom especially during this crisis time in our world. I am doing another MasterClass as a way to reduce stress being a physician far away from my family. Everyday I try think positive and avoid all of the negative stories circulating. I concentrate on what I know and keep daily contact with my family. Thank you, Chris, for sharing a painful time in your life.