What Is a Spacesuit? (1) A spacesuit is much more than a set of clothes astronauts wear on spacewalks. A fully equipped spacesuit is really a one-person spacecraft. The formal name for the spacesuit used on the space shuttle and International Space Station is the Extravehicular Mobility Unit, or EMU. "Extravehicular" means outside of the vehicle or spacecraft. "Mobility" means that the astronaut can move around in the suit. The spacesuit protects the astronaut from the dangers of being outside in space. Why Do Astronauts Need Spacesuits? (2) Spacesuits help astronauts in several ways. Spacewalking astronauts face a wide variety of temperatures. In Earth's orbit, conditions can be as cold as minus 250 degrees Fahrenheit. In the sunlight, they can be as hot as 250 degrees. A spacesuit protects astronauts from those extreme temperatures. (3) Spacesuits also supply astronauts with oxygen to breathe while they are in the vacuum of space. They contain water to drink during spacewalks. They protect astronauts from being injured from impacts of small bits of space dust. Space dust may not sound very dangerous, but when even a tiny object is moving many times faster than a bullet, it can cause injury. Spacesuits also protect astronauts from radiation in space. The suits even have visors to protect astronauts' eyes from the bright sunlight. What Are the Parts of a Spacesuit? (4) The spacesuit consists of several pieces. The Hard Upper Torso covers the astronaut's chest. The arm assembly covers the arms and connects to the gloves. The helmet and Extravehicular Visor Assembly are designed to protect the astronaut's head while still allowing him or her to see as much as possible. The Lower Torso Assembly covers the astronaut's legs and feet. The flexible parts of the suit are made from several layers of material. The layers perform different functions, from keeping oxygen within the spacesuit to protecting from space dust impacts. (5) Underneath the spacesuit, astronauts wear a Liquid Cooling and Ventilation Garment. T