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.

A must watch! Such respect to these astro modern yet renaissance men and women. The comparison of space exploration today and tomorrow to early explorers of earth is apt. This course stimulates exciting thoughts for our future.

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 am two years older than Chris and shared many of the same dreams. Although I never became an astronaut, I did earn a pilots license and have closely followed the space program all my life. Chris’ insights into the workings of NASA and the science of space flight were riveting! Thank you Chris for sharing your time and your experience with me. I am better for having watched your MasterClass!



Ken C.

Every useful tool can hurt you. Every safety rule is written in blood. If you are learning and focused then every near-miss and every injury helps improve the safety of the whole enterprise. The failure is stopping. Pausing and reflecting gives time to learn.

A fellow student

This may have been the best lecture on anything ever. I’m going to share this with as many people as possible.


yup this is great except when his friend died in Colombia the space shuttle

A fellow student

This lesson alone is worth the price of admission! Wonderful perspective, Mr Hadfield!

A fellow student

I was deployed to Iraq during the Columbia tragedy. We had an imbedded reporter from the Wall Street Journal that had word about the Columbia breaking up during re-entry. I can remember when the Columbia firt went up in April of 1981. The shuttle program had 135 missions, with 133 completely successful.

A fellow student

I was working near the Johnson Space Center when the Challenger accident occurred. This accident was bound to happen. Rockets are dangerous and so is exploration. I am glad that we have not stopped exploring. I do think its a shame that the Space Shuttle was retired before something else just a capable or better took its place.

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! 🌎