The hull breaches. Someone gets pulled out into the void and freezes solid, or explodes, or both, in about a second and a half.

The physics of decompression is stranger than the movie version and considerably more survivable in the short term.

Start with what does not happen. You do not explode. Skin is tough and elastic and contains the pressure differential without difficulty. Your blood does not boil — the circulatory system is a closed pressurized loop and holds. You will swell visibly as tissues expand and gases come out of solution, the face puffs, the eyes bulge, and it is not pleasant. But you stay intact.

You do not freeze either. Space is not cold in the way an arctic night is cold. Cold requires matter to carry heat away from you, and vacuum is nearly perfect insulation. Your only route of heat loss is radiation, which is slow. You will die of other things long before temperature becomes the issue.

What actually happens follows a sequence, and the timing is the useful part.

In the first seconds the atmosphere leaves. There is a violent wind toward the breach, ears pop hard, and gas in your sinuses and digestive tract expands painfully. Moisture on your eyes and tongue begins to evaporate, which is reportedly an intensely strange cold sensation. Saliva fizzes.

Then hypoxia takes over, and here is the number that matters: you have roughly ten to fifteen seconds of useful consciousness. That is the window in which self-rescue is possible. Trained astronauts and high-altitude pilots know that figure by heart, because everything depends on reaching oxygen inside it.

And here is the detail that surprises everyone.

Hypoxia does not feel like suffocation. Suffocation — the desperate, panicked need for air — is driven by carbon dioxide accumulating in your blood, not by oxygen running out. In a vacuum the CO2 is leaving too, so the alarm never sounds.

What hypoxia produces instead is euphoria. Warmth, pleasant confusion, a floating sense that everything is fine. It resembles nitrous oxide. People losing consciousness this way have been recorded smiling and giving incorrect answers cheerfully, entirely unaware anything is wrong.

That is not a comfort. It is the brain failing to report its own emergency, and it is why altitude chamber training exists — so pilots learn to recognize their personal hypoxia symptoms before judgment goes.

Past fifteen seconds, unconsciousness. The survivability window runs to roughly ninety seconds. Repressurize inside that and survival with treatment is realistic. Beyond it, the damage compounds past recovery.

We know this partly from a 1966 accident at NASA, when a technician named Jim LeBlanc had his suit pressurization hose disconnect in a vacuum chamber. His last memory before losing consciousness was the saliva on his tongue beginning to boil. He was repressurized in about thirty seconds and walked away.

Ninety seconds is not generous. It is also not zero, and the difference between those two things is the entire subject of emergency training.

You’re Doing It Wrong: Dump the Myths, Misconceptions, and Bad Advice You Believe is here: https://amzn.to/4cX2M4U

And if you enjoy space stories, my Area 51 series has been called “Indiana Jones Meets The Expanse.”