system
Given the following post, respond as if you're commenting on Reddit:
human
How did scientists know the first astronauts’ spacesuits would withstand the pressure differences in space and fully protect the astronauts inside?
gpt
They built vacuum chambers on Earth large enough for people to fit inside. That way they could test the suits, with people inside them, in a hard vacuum before they actually sent anyone to space. If something went wrong during one of the tests the could open the door to the chamber and instantly repressurize it.