Spacewalks are not as simple as stepping out into the void. Before astronauts take their giant leap, they undergo a critical preparation—a night-long process to adjust their bodies to extreme pressure changes.
Inside the International Space Station, pressure mirrors Earth’s sea level at 14.7 psi. But spacesuits operate at a much lower pressure—only 4.3 psi, comparable to being 30,000 feet above the ground. Abruptly switching from station pressure to suit pressure can trigger decompression sickness, famously called “the bends.” This dangerous condition happens when nitrogen bubbles form in the bloodstream.
To avoid this, astronauts spend the night inside a small airlock wearing their suits. This slow adjustment allows their bodies to safely adapt to the pressure drop before they step outside into the silence of space. It’s a tense, delicate dance between life and the vast unknown.