An astronaut breaks down what 'Guardians of the Galaxy Vol. 3' gets right and wrong about Star-Lord almost dying in space: 'Your blood would fizz like opening a can of Coke'

• An astronaut broke down the accuracy of the space scene in "Guardians of the Galaxy Vol. 3."
• In the movie, Star-Lord (Chris Pratt) nearly dies as he drifts through space without a helmet.

A retired astronaut has weighed in on the accuracy of Star-Lord's near-death experience in space in "Guardians of the Galaxy Vol. 3."

In the latest "Guardians" movie, Star-Lord (Chris Pratt) is seen floating through space without a space suit or helmet. In the scene, the hero slowly loses oxygen and his face begins to crystallize with ice and swell up before he is saved by Will Poulter's character.

In a YouTube video published by Vanity Fair this week, Chris Hadfield, a former NASA astronaut and engineer, said that the length of time Star-Lord is seen drifting in space could have dire consequences on a human in real life.

"Our best guess is that you can live outside of a spaceship without a space suit for 30 seconds, really no problem," Hadfield said.

"But beyond about a minute and a half, there's gonna be stuff that happens to you that does permanent, irreversible and deathly damage," Hadfield continued. "90 seconds and you're a satellite."

"Within about 15 seconds, all the oxygen that is in your blood will have now come through your lungs the other way, and you will have breathed it out," explained Hadfield. "So in about 15 seconds, you have blood without enough oxygen in it, and when it gets up to your brain, you'll go unconscious."

As for Star-Lord's face swelling, "That's real." At least, to an extent.

Hadfield explained: "If you popped your helmet off in space, your lungs would sort of collapse, but also your blood would fizz like opening a can of Coke and release the pressure, and suddenly there's bubbles in your blood and in your cheeks and in all of your flesh, and you're gonna swell out."

But, Hadfield added: "Not as much as he's swelling up here."

According to Hadfield, the crystallization on Star-Lord's face, however, is less accurate to what might happen in real life.

"It wouldn't happen like that," said the retired astronaut. "There's no water on your face. It's not going to instantaneously freeze. You got a lot of thermal mass. It's like sticking a big roast in the freezer — it doesn't instantaneously freeze. It takes a while."