spacesuit

A spacesuit, or space suit, is a wearable garment that enables humans to operate in the vacuum of space or other extreme environments. It provides life support, maintains pressure, regulates temperature, and shields the wearer from radiation and micrometeoroids, while preserving dexterity and mobility for tasks outside a spacecraft.

A spacesuit typically comprises an airtight outer envelope, a pressure garment, mobility joints, a helmet with visor, gloves, and a portable life support system (PLSS) backpack. The PLSS supplies oxygen, removes carbon dioxide, controls humidity and temperature, and powers communications and cooling. The suit has multiple layers for protection, ventilation, and abrasion resistance, plus a thermal insulation system and a water cooling garment worn under the pressure layer.

Two major classes exist: IVA suits designed for use inside a spacecraft during non-pressurized operations, which require less protection, and EVA suits designed for extravehicular activity in open space, equipped with higher protection and life support capabilities. Modern EVA suits may be used with the spacecraft’s airlock or in airlocks on space stations.

Historically, space suits evolved from high-altitude pressure suits used in aviation to protect pilots in near-space conditions. NASA’s Gemini and Apollo programs advanced EVA capability, culminating in the Apollo A7L/EMU suit with a dedicated PLSS. Contemporary EVA suits, such as the U.S. Extravehicular Mobility Unit and Russian Orlan, emphasize improved mobility, reliability, and integration with docking systems and robotic tools.

Spacesuits are designed with redundancy and safety in mind, featuring fail-safes for oxygen, power, and life-support systems, as well as communications and monitoring. They are maintained under strict protocols and routinely tested before missions.