Why Does an Astronaut Need a Spacesuit?
A spacesuit enables an astronaut to survive by providing him artificially with conditions like those he is used to on Earth. These conditions can be reproduced in a large space craft or space station in orbit, but an astronaut still needs a spacesuit for operations outside the craft or for an emergency. In space men lack the air needed for breathing, the pressure required to stop their blood from boiling and the natural protection of the atmosphere against radiation.
All these must be supplied by the spacesuit which also must withstand the cold of space. When an astronaut ventures into space, he leaves behind the safety of the atmospheric blanket which we, on earth, take for granted. His spacesuit becomes his own personal little world. Spacewalking astronauts face a wide variety of temperatures. In Earth 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.
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.
A spacesuit is made up of many parts. One part covers the astronaut’s chest. Another part covers the arms and connects to the gloves. The helmet protects the head. And the last part covers the astronaut’s legs and feet. Some parts of the suit are made of many layers of material. Each layer does something different. Some keep oxygen in the suit while others protect astronauts from space dust.
Under the suit, astronauts wear another piece of clothing. It covers their body except for the head, hands and feet. Tubes are woven into it. Water flows through the tubes to keep the astronaut cool. On the back of the spacesuit is a backpack. The backpack holds oxygen so astronauts can breathe. It also removes carbon dioxide that astronauts have breathed out. The backpack also supplies electricity for the suit. A fan moves the oxygen through the spacesuit. A water tank holds the cooling water. Connected to the back of the suit is a tool called SAFER. SAFER has several small thruster jets. If an astronaut floated away from the space station, he or she could use SAFER to fly back.
Modern space suits augment the basic pressure garment with a complex system of equipment and environmental systems designed to keep the wearer comfortable, and to minimize the effort required to bend the limbs, resisting a soft pressure garment’s natural tendency to stiffen against the vacuum. A self-contained oxygen supply and environmental control system is frequently employed to allow complete freedom of movement, independent of the spacecraft.
Three types of spacesuits exist for different purposes: IVA (intravehicular activity), EVA (extravehicular activity), and IEVA (intra/extravehicular activity). IVA suits are meant to be worn inside a pressurized spacecraft, and are therefore lighter and more comfortable. IEVA suits are meant for use inside and outside the spacecraft, such as the Gemini G4C suit. They include more protection from the harsh conditions of space, such as protection from micrometeorites and extreme temperature change. EVA suits, such as the EMU, are used outside spacecraft, for either planetary exploration or spacewalks. They must protect the wearer against all conditions of space, as well as provide mobility and functionality.
Some of these requirements also apply to pressure suits worn for other specialized tasks, such as high-altitude reconnaissance flight. At altitudes above the Armstrong limit, around 19,000 m (62,000 ft), water boils at body temperature and pressurized suits are needed. The first full-pressure suits for use at extreme altitudes were designed by individual inventors as early as the 1930s. The first space suit worn by a human in space was the Soviet SK-1 suit worn by Yuri Gagarin in 1961.