written by: Jason C. Chavis•edited by: RC Davison•updated: 8/7/2011
Space suit design has changed over the course of time. The basic principle is to maintain an environment that will keep a person alive in the harsh conditions of space. These include controls on pressure, temperature and safety. Steps are being taken now to make further advancements in space suits.
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Keeping an Astronaut Alive
Space suits are a necessity for traveling into space. Specifically, they are used to keep a person alive while performing certain tasks in high-altitude space flights. The atmosphere is incredibly thin above 62,000 feet from the surface and can cause the human body's fluids to boil. This area is known as Armstrong's Line, named after a U.S. Air Force surgeon who identified it.Pressurized space suits are required for any activity outside a controlled environment such as the International Space Station, space shuttle or a capsule. This includes space walks or on the Moon.
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Necessities of the Space Suit
A space suit must retain a stable internal pressure. To make this work, engineers have developed a containment system that allows people to re-breathe pure oxygen at a lower pressure than inside earth's atmosphere. This allows for greater mobility and avoids the problems with decompression sickness.
Temperature regulation is also important. The temperature of space varies greatly between shadow and sunlight, ranging from -160 degrees C to 120 degrees C. This requires the suit to be heavily insulated and the inside to be controlled by maintaining a constant temperature in the air and with liquid cooling technology placed against the astronaut's body.
Space suits also shield against particle and ultraviolet radiation as well as offer limited protection against micrometeroids, space debris in the earth's atmosphere. These suits also provide for tether options for space walks, a system for collecting solid and liquid waste and an advanced communication system.
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The first space suit was designed in a joint-project between the B.F. Goodrich Company and the U.S. Navy. Known as the Navy Mark IV, it was originally used for high-altitude military fighters before being adapted for Project Mercury. A similar design was worn by Yuri Gagarin on his first flight into space aboard to Vostok spacecraft.
The next advancements were made by the Soviet Berkut space suit design and NASA's Gemini mission suits. These included the first elements of a primary life support system that allowed for spacewalks.
Nearly all of the elements that make modern space suit functions were simultaneously implemented by the Soviet space program and NASA during the 1960s. The Krechet space suit and Apollo moon suits allowed for extended exposure to the elements of high-altitude space flight as well as the Moon landing.
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Modern Space Suits
The Russian, NASA and Chinese space programs use a very similar design for space suits. Each provides basic life support systems for launch and reentry procedures. When on board the Soyuz spacecraft, cosmonauts wear the Sokol space suit. The shuttle crew uses the Advance Crew Escape System Pressure Suit, specifically designed for the event of a shuttle failure and loss of pressurization rather than space walks. The Chinese model, Shenzhou 5, is used on board that country's craft.
The most modern design is the Extravehicular Mobility Unit. This is a model of space suit used for space walks aboard the shuttle and International Space Station. In addition to providing all of the necessities to survive in space, it can also provide an astronaut with the ability to conduct independent space flight away from a capsule, shuttle or the space station.
Also used on the space station is the Russian-designed Orlan space suit. This was originally developed during the late 1970s and has been used consistently onboard the Mir space station and now the International Space Station. The semi-rigid construction of the Orlan offers greater flexibility in the arms than other models and a durable torso and head piece. It also features a rear-entry access point, making the time to put on the suit a mere five minutes. It also has a longer battery life than most other suits, lasting for over nine hours.
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The two most likely space suits to replace the present models are known as the Mark III and the I-Suit, both under construction by ILC Dover. They incorporate both hard-shell and soft components for weight-saving options. The bonus of this suit is that it operates with a higher internal pressure and can incorporate nitrogen into the breathing system. A traditional space suit works at a much lower internal pressure and uses nearly pure oxygen, which requires a lengthly pre-breathing regime to use the suit when the astronauts are in a nitrogen/oxygen atmosphere to prevent the bends. Due to the fact that nitrogen is included, decompression sickness becomes an impossibility.
NASA is under development of a new space suit design for its Constellation program. The concept is a single suit design that can be used for launch and reentry, space walks, lunar exploration and Mars surface reconnaissance.
NASA's Ames Research Center is also underway developing a type of space suit called a suitport. Instead of using an airlock, suits would be attached to the outside of a spacecraft or space station and an astronaut would enter the suit and be fastened up in the back. The suitport would then detach from the ship and a person could conduct necessary EVA. The space and mass considerations as well as safety from space dust are the primary advantages of this system.
Since the dawn of the space program, the need for space suit design to protect astronauts and cosmonauts was a necessity. NASA focused its early attempts on the Apollo mission, but as new reasons for space travel were adopted the space suits changed with the times.