Space Suits

Protective suits were unnecessary until airplanes achieved fast speeds and high-flight altitudes. Medical researchers then conducted a special study of human physiology during flight. New, stronger, high-temperature-resistant synthetic materials were developed. This research permitted humans to walk in space and on the Moon and made it possible to build and maintain a permanent space station.

1930s: Early Pressure Suits

In 1933 Wiley Post, while flying air races, discovered that he could not fly in the jet stream unless he had a pressurized enclosed cabin or wore a pressurized suit. After Post contacted the B. F. Goodrich Company, engineer Russell Colley's group designed a suit that could hold 1.1 kilograms (2.4 pounds) of pressure. Two latex-dipped metal forms spliced together shaped the upper and lower torso. The outer layer of three-ply cotton fabric with arms allowed the wearer to reach the stick and throttle. Post, in this pressure suit, made several successful stratospheric flights in his plane, The Winnie Mae.

1940s: World War II Flight Needs

In the early 1940s, the U.S. Army and Navy became interested in Colley's work on pressure suits. After Colley saw a tomato worm in his garden turn 90 degrees without a perceptible increase in pressure anywhere on its body, the team adapted segmented bellows for the arms and legs of the suit. This gave the pilot rudimentary mobility and the ability to assume a sitting position.

But other flight problems had to be solved. B-24 and B-25 crews in mass bombing raids mysteriously crashed with no evidence of their having made attempts to escape. The concept of G forces , a new term for acceleration and the resulting problems, was consequently realized. A partial pressure suit developed by James Paget Henry at the University of Southern California produced the next important development. Anti-g suits based on Henry's bladder-type antigravity construction, commonly called g-suits, evolved as close-fitting garments with rubber bladders. As the plane reached a high altitude and developed greater speed, the suit automatically inflated with gas. This provided pressure to the calves, thighs, and abdomen to offset the increased pressure of acceleration on arterial blood flow in those areas. Aeromedical physicians found that blood pooled in the lower body at high altitudes and thus was not forced back toward the heart and recirculated to the head. Fatigue, loss of vision, and unconsciousness set in. Today all pilots of long-duration high-speed, and high-altitude planes wear g-suits.

1950s: Emergence of the Cold War and the Space Race

Both the United States and the Soviet Union, using captured German V-2s, pursued exploration of the upper atmosphere. On November 1, 1952, the United States detonated the world's first thermonuclear explosion; the Soviets exploded their device in 1953. This spurred intercontinental ballistic missile (ICBM) development.

On October 4, 1957, the Soviets successfully launched Sputnik 1, the first satellite in space, whereas the U.S. Explorer 1 achieved orbit on January 31, 1958. And thus, the space race was on. Unpiloted American and Soviet spacecraft carrying mice, chimpanzees, monkeys, dogs, and other small animals were sent into space and returned above modified German V-2s.

1960s: Human Spaceflight

Modified ICBM rockets successfully boosted the first humans into space. On April 12, 1961, the Russian cosmonaut Yuri Gagarin aboard Vostok 1 lifted off into space to achieve the first Earth orbit. On May 5, 1961, astronaut Alan Shepard aboard Freedom 7 became the first American to complete a suborbital spaceflight.

Shepard's space suit had zippered openings, a neoprene-coated nylon layer to prevent leakage, an airtight neck ring bearing, fabric-fluted shoulder and knee joints, and an overgarment fabricated of high-temperature-resistant aluminized nylon. The helmet locked onto the suit's special padded neck ring.

Gagarin's Sokol space suit used a similar multiple-layered construction but had a bladder system made of natural rubber instead of synthetic rubber. The Soviets also used restraint layers to give shape and attach boots, gloves, and a helmet. Hardware sealing materials were all made of natural rubber. The Russians fabricated cover layers from their version of nylon restraint materials. Both suit systems used an internal duct system to remove carbon dioxide from the helmet area and facilitate cooling.

Mid-1960s: The Gemini Program and Walks in Space

On March 18, 1965, Edward White became the first American to walk in space. His twenty-layer suit contained biomedical amplifiers to relay information about the astronaut's pulse and blood pressure. A bladder layer contained rubberized nylon to hold air during compression. Dacron cord woven like fishnet, called linknet, restrained the bladder layer. An aluminized-coated, high-temperature nylon antisnag garment covered the suit. A portable Gemini extravehicular life support system (ELSS) chest pack and umbilical provided electrical wires for communication and bioinstrumentation transmittal.

Late-1960s: Apollo to the Moon

For Apollo missions lunar space suits protected astronauts from lunar temperatures between -150 and 120°C (-238 and 248°F), cosmic radiation , and exposure to high-speed meteoroid particles in gravity one-sixth that of Earth.

The astronauts inside the spacecraft wore five-layer suits. Astronauts on extravehicular walks wore the twenty-one-layer garment over a three-layer liquid cooling garment. Mylar polyester film added tensile strength, resistance to chemicals and moisture, and the ability to withstand fluctuations in the lunar temperature. Kapton combined with Teflon provided a stable insulating material. Beta cloth with Teflon added tensile strength and abrasion resistance. A fishbowl-like helmet replaced the pilot-style closed helmet. The Apollo suit, including the primary life support system, weighed about 81 kilograms (180 pounds). Neil Armstrong and Buzz Aldrin gave the Apollo suit high marks after their July 20, 1969, Apollo 11 lunar excursions.^*

1970s to Present Day

Reusable space shuttle suits, or extravehicular mobility units (EMU), are modular and are designed to fit both male and female astronauts. For flight, the astronaut puts on a liquid cooling and ventilation garment, a one-piece suit made of Spandex mesh covered with 91.5 meters (300 feet) of cooling water tubing. Then the lower torso assembly (pants) is pulled on. The astronaut then thrusts the arms up into the hard upper torso and backpack hanging on the wall and hooks the two pieces together. The gloves and bubble helmet assembly go on last.

The space suit alone weighs 47 kilograms (104 pounds), the primary life support system adds another 67 kilograms (148 pounds), and the helmet, lights, and camera, at 3.6 kilograms (8 pounds), bring the total weight of the EMU to 117.6 kilograms (260 pounds). The gloves, with miniature heating units, are now custom-fitted at a cost of approximately $20,000 apiece. A suit costs approximately $1.5 million.

The modular EMU used in conjunction with the construction of the International Space Station has been modified to be capable of 25 EVAs (walks in space) and can stay in orbit up to 9 months. The suits used today have a life expectancy of about 25 years.

Future Martian Exploration

ILC and Hamilton Sunstrand engineers are developing a suit that is especially nimble yet sturdy enough for long walks through difficult terrain. Astronauts need sufficient mobility to recover from falls, carry their backpacks, and complete geological experiments. The gravity on Mars is three-eighths that of Earth, compared to the one-sixth gravity on the Moon. The new suits use soft fabric and lightweight aluminum, making them lighter, cheaper, and easier to put on and take off, with greater mobility for an operational environment of fractional gravity or even zero gravity. The aluminum surface will allow higher pressure than the space shuttle/space station suits—about 8.3 psi—which is closer to Earth-like atmospheric pressures, eliminating the need to prebreathe pure oxygen.

see also Apollo (volume 3);Life Support (volume 3); Sanitary Facilities (volume 3); Space Walks (volume 3).

Lillian D. Kozloski

Bibliography

Arnold, H. J. P., ed. Man In Space. New York: Smithmark, 1993.

Baker, David. The History of Manned Spaceflight. New York: Crown, 1981.

Clark, Phillip The Soviet Manned Space Program, New York: Orion, 1988.

Kozloski, Lillian. U.S. Space Gear. Washington, DC: Smithsonian Institution Press,2000.

Mohler, Stanley R., and Bobby H. Johnson. Wiley Post, His Winnie Mae, and the World's First Pressure Suit. Washington, DC: Smithsonian Institution Press, 1971.

Sawyer, Kathy. "Suited for Space." Washington Post, October 14, 1998: H-1, 4, 5.

Warren, Michael. "Inside the Spacesuit." Final Frontier (January-February 1999):30-35.

Wilde, Richard C., Isaak P. Abramov, and James W. McBarron II. Extravehicular Individual Life Support: A Comparison of American and Russian Systems. SAE Paper No. 932223. Paper presented at the 23rd International Conference on Environmental Systems, Colorado Springs, CO, July 12-15, 1993.

^*The U.S. astronauts during the Apollo missions were the first and only humans to land and walk on the Moon.