How do spacesuits keep astronauts alive outside a spacecraft?

A modern spacesuit is much more than clothing: it is a compact life-support system. It provides pressure so the human body can function, supplies oxygen, removes carbon dioxide, and controls temperature using cooling garments and insulation. The outer layers also protect against ultraviolet radiation and tiny high-speed particles. NASA’s current Extravehicular Mobility Unit suits support spacewalks outside the International Space Station, while newer suits are being developed for Artemis lunar missions. A suit’s helmet, gloves, and joints are engineered so astronauts can move while still being sealed from the vacuum.