Astronauts always seem cool under pressure. Whether these space professionals are dealing with water filling their helmets during a space walk or a possible ammonia leak on the space station, folks listening to their talks with ground control can always count on some surprisingly chill vibes.

[Reported ammonia leak on the International Space Station proves to be false alarm]

That's not because astronauts are totally fearless. It's because they train for just about anything that could go wrong during their space missions over and over again. In the above video from the European Space Agency, ESA astronaut Andreas Mogensen and Russian cosmonaut Sergei Volkov show a typical training session in preparation for flight to the International Space Station. Once suited up and seated in the simulator, they're subjected to a random assortment of disasters and expected to calmly follow emergency procedures to save themselves.

One of the big benefits of this dress rehearsal is that it will help the men stay calm under pressure should something go wrong in space. Retired Canadian astronaut Chris Hadfield explains this in his book "An Astronaut's Guide to Life on Earth":

Naturally then, when people try to imagine what it feels like to sit in a rocket with the engines roaring and firing, they assume it must be terrifying. And it would be terrifying if you were plucked off the street, hustled into a rocket ship and told you were launching in four minutes – and oh, by the way, one wrong move and you’ll kill yourself and everybody else. But I’m not terrified, because I’ve been trained, for years, by multiple teams of experts who have helped me to think through how to handle just about every conceivable situation that could occur between launch and landing. Like all astronauts, I’ve taken part in so many highly realistic simulations of space flight that when the engines are finally roaring and firing for real, my main emotion is not fear. It’s relief. At last.

Fear, he goes on to suggest, comes from lack of knowledge. "When you feel helpless, you’re far more afraid than you would be if you knew the facts," Hadfield writes. "If you’re not sure what to be alarmed about, everything is alarming."

But thanks to training like the session shown in the above video, astronauts tend to be prepared for every situation. They may be nervous when something goes wrong -- they're not robots, after all -- but they're able to keep their cool and follow the procedures that will keep them alive.

And that's good, because putting out a fire on the Soyuz isn't as simple as grabbing an extinguisher -- there isn't one. After trying to choke the fire by turning off fans and trying to kill the source by turning off electrical systems (hopefully temporarily), the next step is depressurization. Fires can't exist in the vacuum of space, but an astronaut in a spacesuit will be just as kaput after a couple of hours. In the event of a fire that can only be put out by depressurizing the Soyuz, astronauts have to make a speedy return back to Earth to avoid dying of heat exhaustion.

In the simulator, at least, the men were able to keep their cool.

"We had to depressurize to get rid of the fire," Mogensen tells the camera, "But we managed and survived, so...just another day at the office."

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