Spacesuits are essential components in space exploration. These suits provide the astronauts protection from the harsh elements, while providing some level of comfort and support. Pressurized flight suits were first made to protect the jet aircraft pilots from the bad effects of high altitude, such as low oxygen levels that are associated with the decrease of atmospheric pressure. Numerous spacesuits have been designed and manufactured over the years. Their designs have evolved along with the current available materials and technologies, and their functionalities have been adapted to the different short and long term space missions.

Since the internal atmosphere of the spacecraft is controllable and has normal air, regular clothing can be worn by the astronauts. However, a spacesuit or pressure suit is needed for outside space exploration. The main purpose of the spacesuit is to protect human beings from an environment that is different from Earth’s normal environment. Humans need protection from the harsh elements of outer space, such as radiation, unregulated temperature, absence of atmospheric pressure, and lack of oxygen.

The dry air on Earth’s atmosphere is made up roughly of 21 percent oxygen, 78 percent nitrogen, 0.93 percent argon, 0.038 percent carbon dioxide, and small amounts of water vapor and gases. The atmosphere becomes thinner as it goes higher in altitude into the five main layers: the troposphere, the stratosphere, the mesosphere, the thermosphere and the exosphere. At 68 miles up, the imaginary line called the Karman line, is where space begins. In space, the atmospheric pressure is extremely low, there is no oxygen, and the temperature is extremely hot and cold.

The thin atmospheric pressure in space is not enough to maintain a person’s normal blood pressure, causing the person’s body fluids to boil and freeze. The spacesuit’s neoprene fabric restricts the air pressure within the pressurized suit, thus supplying the proper air pressure when worn by the astronaut and preventing the body fluids from boiling and freezing.

The lack of oxygen in space will cause unconsciousness and death rapidly. Since the thin atmospheric pressure will cause low oxygen levels in the astronaut’s blood and lungs, pure oxygen is used and flows into the spacesuits through an umbilical cord attached to the spacecraft or a life support system that is carried like a backpack.

The carbon dioxide that comes out of the astronaut would build up to unacceptable levels when confined within the spacesuit. To deal with this problem, the spacesuits are equipped with canisters of lithium hydroxide, which are used to remove the carbon dioxide. The canisters of lithium hydroxide are either accessed through the umbilical cord that is attacked to the spacecraft or through a life support system that is carried like a backpack.

Without the Earth’s atmosphere in space, the human body will not be able to cope with the extreme hot temperature of the area facing the sun and the extreme cold temperature of the area facing the dark space. The insulation of layers of rubberized, breathing fabric and outer layers of reflective material allow the space suit to deal with the extreme hot and cold temperatures in space. Spacesuits use internal fans or water-cooled garments to remove the body heat and the subsequent perspiration that is produced by the astronaut during strenuous activities.

Aside from protecting the astronauts from the extreme temperatures and thin atmospheric pressure, and providing oxygen for breathing, the durable fabrics in the spacesuits protect the astronauts from micrometeroids, which are very small pieces of rock or metal debris floating in space. The reflective fabrics used in the spacesuits also give some protection from radiation. The tinted domed helmets that come with the spacesuits are made of durable, clear plastic that provide clear vision. The radio with transmitters and receivers, in combination with the headsets, microphones, and earphones, allow the astronauts to communicate with each other and also with the ground controllers.

Alan Shepard
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Mercury

NASA’s Mercury program utilized the design of a U.S. Navy Mark IV

Gordon Cooper
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pressure suit for its space orbital flight. The pressure suit was modified by an addition of layers of silver Mylar on top of the rubberized fabric. To allow mobility, break lines were sewn into the fabric in the area of the elbows and knees. The Mercury spacesuit included boots with laces, gloves, and a helmet with a collar ring. The oxygen hose was attached to the suit from the space craft. The modified Navy pilot suit was worn by the Mercury astronauts without pressure or unpressurized, which was in its “soft” state. The purpose of the Mercury Project pressure suits was for backup only in the event of loss in cabin pressure, which never occurred, and these were not intended for space walking. 

Gemini

Gus Grisson & John Young
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NASA’s Gemini program needed spacesuits for space walking, which the Mercury spacesuits were not designed to do. Since it was also difficult for astronauts to move in the Mercury spacesuits when pressurized, changes were made to the Mercury spacesuit to adjust to the Gemini program. Neoprene and layers of Teflon nylon were used on the Gemini spacesuit, and it was soft when pressurized. The oxygen and cooling system were supplied through an umbilical cord and attached to the spacecraft.

Neil Armstrong
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The overheated astronauts in the Gemini program soon learned that the cooling system in their spacesuits did not do its job well. They would easily tire from the space walks, and excessive moisture fogged up their helmets. The cooling system was modified to a portable air conditioner box that was attached to the space suit through an umbilical cord.

The Gemini-Titan 4 was the first American spacewalk. Astronaut Edward White floated in zero gravity of space. He was connected to an umbilical cord and a tether line, which were attached to the spacecraft. White used a Hand-Held Self-Maneuvering Unit (HHSMU) to move around.

Apollo

Buzz Aldrin
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The Apollo mission needed spacesuits that would be used for walking on the moon and space flight, and a spacesuit was developed that accommodated both. The spacesuits needed protection from sharp Moon rocks, protection form the lunar heat, and flexibility that would allow the astronauts to easily pick up Moon samples. The improved mobility on the Apollo spacesuit used molded rubber joints. The Apollo spacesuit used a water-cooled undergarment, multiple layers of neoprene and lightweight nylon to hold the pressurized layers underneath, layers of silver Mylar, Dacron, and Kapton materials for protection from heat, and Teflon layers to protect from scrapes, boots, gloves, and helmet. For the moon walk, the astronauts wore protective overboots and protective filters for the helmet. They carried a portable life support backpack. Subsequent modifications to the spacesuit added better flexibility that allowed the astronauts to sit inside the lunar rover vehicle.

Space Shuttle

Bruce McCandless
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The Space Shuttle spacesuit’s main purpose is for zero gravity missions, and it needed to last 15 years. While the Apollo spacesuits have been made to order to fit each astronaut, the Space Shuttle spacesuit were produced using interchangeable parts to accommodate multiple astronauts with varying body types. The components are gathered and fitchecked to each astronaut. Out in space, the astronauts wear the Extravehicular Mobility Unit  (EMU), which is made up of both hard and soft materials. The EMU is used in conjunction with the primary life support system (PLSS), which is a backpack that is permanently attached to the suit’s hard upper torso (HUT). The PLSS provides the oxygen, pressurization, cooling, and ventilation, and it also absorbs the carbon dioxide. The astronauts move around in space through the use of the manned maneuvering unit (MMU), which is a nitrogen-propelled backpack. It is attached to the PLSS, and it includes a 35-mm camera for the astronaut's use.

Future Design

Professor Dava Newman
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With the Space Launch System (SLS) looming in the near future, there is excitement at what the new spacesuit would look like. The lightweight and skin-tight BioSuit, which is designed by engineer and professor of astronautics at the Massachusetts Institute of Technology Dava Newman looks fashionably chic. It is primarily made up of nylon and spandex, which allows better flexibility. ILC Dover, the manufacturer of the Shuttle spacesuits, sees the BioSuit as impractical because it doesn’t seem to tackle the challenges of space’s hostile environment.

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The efforts to replicate the Earth’s environment inside the spacesuits have given humans the chance to explore space in relative safety. Although the functionality of these spacesuits is first and foremost at the core of its design, the iconic fashion of the bulbous suit makes it a favorite symbol of space exploration. The evolution of the spacesuit designs reflect new technologies, and will continue to evolve as new materials are invented and as we explore new frontiers in space.

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