Science & Technology

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
In 28+ lessons, the former commander of the International Space Station teaches you the science of space exploration and what the future holds.
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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...

Explore the unknown

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.

What an amazing, exceptional human being. He teaches more that space exploration... Everyone should watch his masterclass!

Phenomenally inspirational story, and deeply interesting content. One small course for Masterclass, one giant leap for my ambitions and focus!

I absolutely loved this Masterclass. I am just finishing highschool, going into university, and one day, I hope to become an astronaut. This class showed me the challenges my dream presents me with and taught me how to overcome them. Thank you!

Unfortunately way to old to be an astronaut. But Chris's teaching style and journey are truly inspiring for young and old alike and i will try to take some of his lessons on outlook on life and apply them to my day to day.


A fellow student

Shocked by just how great this MasterClass has been. This particular episode is so inspiring, a reminder that OF COURSE new experiences and exploration comes with additional risks. It’s important to decide if you’re a person who is willing to accept those risks to advance themselves and those around them.

Jamal M.

I loved this lesson, so many situations that can be compared to life and different areas of life. How do deal with risk, with failure, with danger itself. "The thing is itself is not scary, your reaction to it is fear." This is key.

Christopher R.

Great lesson on the philosophy of dealing with risk. I think the title of the second part, however, is supposed be," Coming to Peace with Risk and Learn From Tragedy", rather than,"Coming to Piece with Risk and Learn From Tragedy".

ahmad T.

I just became CC in NJROTC in high school 10th grade, and my teacher said if I actually study in it university, I can be an astronaut, it’s like being a pilot! 🌎

Cynthia K.

Time and again, through my life, I have had situations where I needed that "push" to move on. As an engineer in flight test for the government (yes like Chris, I have seen people die), with my music, everything. I get that feeling of "well its not a great situation, but its comfortable" its familiar - its predictable. Risk is hard to accept - the little "what if" voice. I have followed the space program since Al Shepard made a ballistic down range lob, launched from a Redstone. And I watched 51-L - and that terrible call from the vehicle "Go at throttle up". I can not hear that now without a chill. I was in New Mexico when Columbia was breaking up - you could see it it. But as Chris says if you stop trying and say I can't - then you stop. Progression ceases. I feel Chris is speaking directly to me, and I have listened. Its time for me to move on, move up and get my music production business off the launching pad, and get out of my comfortable little nest and fly. Thank you Chris.

A fellow student

This entire class is so well done. Even talk of the dangers of space exploration is insightful, emotional, and personal.

Ugo A. D.

Pretty emotional. You realize that we are humans and with the great rewards of space flight, comes the potential for disaster. It made me realize that to be an astronaut, you had to have the "right stuff". Science and engineering can only take you so far, the incredible courage and tenacity of these individuals will pave the wave for future generations. I salute you.

Sergio N A.

Chris you are a Spirit driven person. Risk taker with No room for fear, motivated and seek to be competent in what you choose and comes out successful and eager to move forward whatever happens...that is what a human being should be ....from Sergio Andres Jr.


Anything worth doing involves risk? Damn right. And "things aren't scary, people are scared."? Wow--that's really good. I forgot about that the first time I watched this. Learn and evolve...this was a super useful lesson and I'll be coming back to it often. I love how he puts things.

Jim S.

It was nice to have this interlude. I have heard from several astronauts, but I like this one and how he reflects on the loss of his friend the best.