The History of Spacesuits

The History of Spacesuits The pressure suit for Project Mercury was designed and first developed during 1959 as a compromise between the requirements for flexibility and adaptability. Learning to live and move within aluminum-coated nylon and rubber garments, pressurized at five pounds per square inch, was like trying to adapt to life within a pneumatic tire. Led by Walter M. Schirra, Jr., the astronauts trained hard to wear the new spacesuits. Ever since 1947, the Air Force and the Navy, by mutual agreement, had specialized in developing partial-pressure and full-pressure flying suits for jet pilots, respectively, but a decade later, neither type was quite satisfactory for the newest definition of extreme altitude protection (space). Such suits required extensive modifications, particularly in their air circulation systems, to meet the needs of the Mercury space pilots. More than 40 experts attended the first spacesuit conference on January 29, 1959. Three primary competitors - the David Clark Company of Worcester, Massachusetts (a prime supplier for Air Force pressure suits), the International Latex Corporation of Dover, Delaware (a bidder on a number of government contracts involving rubberized material), and the B. F. Goodrich Company of Akron, Ohio (suppliers of most of the pressure suits used by the Navy) - competed to provide by the first of June their best spacesuit designs for a series of evaluation tests. Goodrich was finally awarded the prime contract for the Mercury space suit on July 22, 1959. Russell M. Colley, along with Carl F. Effler, D. Ewing, and other Goodrich employees, modified the famous Navy Mark IV pressure suit for NASAs needs in space orbital flight. The design was based on the jet flight suits, with added layers of aluminized Mylar over the neoprene rubber. Pressure suits also were designed individually according to use - some for training, others for evaluation and development. Thirteen operational research suits first were ordered to fit astronauts Schirra and Glenn, their flight surgeon Douglas, the twins Gilbert and Warren J. North, at McDonnell and NASA Headquarters, respectively, and other astronauts and engineers to be specified later. A second order of eight suits represented the final configuration and provided adequate protection for all flight conditions in the Mercury program. The Mercury Project spacesuits were not designed for space walking. Spacewalking suits were first designed for Projects Gemini and Apollo. History of Wardrobes for Space The Mercury spacesuit was a modified version of a U.S. Navy high altitude jet aircraft pressure suit. It consisted of an inner layer of Neoprene-coated nylon fabric and a restraint outer layer of aluminized nylon. Joint mobility at the elbow and knees was provided by simple fabric break lines sewn into the suit; but even with these break lines, it was difficult for a pilot to bend his arms or legs against the force of a pressurized suit. As an elbow or knee joint was bent, the suit joints folded in on themselves reducing suit internal volume and increasing pressure. The Mercury suit was worn soft or unpressurized and served only as a backup for possible spacecraft cabin pressure lossan event that never happened. Limited pressurized mobility would have been a minor inconvenience in the small Mercury spacecraft cabin. Spacesuit designers followed the U.S. Air Force approach toward greater suit mobility when they began to develop the spacesuit for the two-man Gemini spacecraft. Instead of the fabric-type joints used in the Mercury suit, the Gemini spacesuit had a combination of a pressure bladder and a link-net restraint layer that made the whole suit flexible when pressurized. The gas-tight, man-shaped pressure bladder was made of Neoprene-coated nylon and covered by load bearing link-net woven from Dacron and Teflon cords. The net layer, being slightly smaller than the pressure bladder, reduced the stiffness of the suit when pressurized and served as a sort of structural shell, much like a tire contained the pressure load of the inner tube in the era before tubeless tires. Improved arm and shoulder mobility resulted from the multi-layer design of the Gemini suit. Walking on the Moons surface a quarter million miles away from Earth presented a new set of problems to spacesuit designers. Not only did the Moon explorers spacesuits have to offer protection from jagged rocks and the searing heat of the lunar day, but the suits also had to be flexible enough to permit stooping and bending as Apollo crewmen gathered samples from the Moon, set up scientific data stations at each landing site, and used the lunar rover vehicle, an electric-powered dune buggy, for transportation over the surface of the Moon. The additional hazard of micrometeoroids that constantly pelt the lunar surface from deep space was met with an outer protective layer on the Apollo spacesuit. A backpack portable life support system provided oxygen for breathing, suit pressurization, and ventilation for moonwalks lasting up to 7 hours. Apollo spacesuit mobility was improved over earlier suits by use of bellows-like molded rubber joints at the shoulders, elbows, hips and knees. Modifications to the suit waist for Apollo 15 through 1 7 missions added flexibility making it easier for crewmen to sit on the lunar rover vehicle. From the skin out, the Apollo A7LB spacesuit began with an astronaut-worn liquid-cooling garment, similar to a pair of long johns with a network of spaghetti-like tubing sewn onto the fabric. Cool water, circulating through the tubing, transferred metabolic heat from the Moon explorers body to the backpack and thence to space. Next came a comfort and donning improvement layer of lightweight nylon, followed by a gas-tight pressure bladder of Neoprene-coated nylon or bellows-like molded joints components, a nylon restraint layer to prevent the bladder from ballooning, a lightweight thermal super insulation of alternating layers of thin Kapton and glass-fiber cloth, several layers of Mylar and spacer material, and finally, protective outer layers of Teflon-coated glass-fiber Beta cloth. Apollo space helmets were formed from high strength polycarbonate and were attached to the spacesuit by a pressure-sealing neck ring. Unlike Mercury and Gemini helmets, which were closely fitted and moved with the crewmans head, the Apollo helmet was fixed and the head was free to move within. While walking on the Moon, Apollo crewmen wore an outer visor assembly over the polycarbonate helmet to shield against eye damaging ultraviolet radiation, and to maintain head and face thermal comfort. Completing the Moon explorers ensembles were lunar gloves and boots, both designed for the rigors of exploring, and the gloves for adjusting sensitive instruments. The lunar surface gloves consisted of integral structural restraint and pressure bladders, molded from casts of the crewmens hands, and covered by multi-layered super insulation for thermal and abrasion protection. Thumb and fingertips were molded of silicone rubber to permit a degree of sensitivity and feel. Pressure-sealing disconnects, similar to the helmet-to-suit connection, attached the gloves to the spacesuit arms. The lunar boot was actually an overshoe that the Apollo lunar explorer slipped on over the integral pressure boot of the spacesuit. The outer layer of the lunar boot was made from metal-woven fabric, except for the ribbed silicone rubber sole; the tongue area was made from Teflon-coated glass-fiber cloth. The boot inner layers were made from Teflon-coated glass-fiber cloth followed by 25 alternating layers of Kapton film and glass-fiber cloth to form an efficient, lightweight thermal insulation. Nine Skylab crewmen manned the Nations first space station for a total of 171 days during 1973 and 1974. They wore simplified versions of the Apollo spacesuit while doing the historic repair of the Skylab and changing film canisters in the solar observatory cameras. Jammed solar panels and the loss of a micrometeoroid shield during the launch of the Skylab orbital workshop necessitated several space walks for freeing the solar panels and for erecting a substitute shield. The spacesuit changes from Apollo to Skylab included a less expensive to manufacture and lightweight thermal micrometeoroid over garment, elimination of the lunar boots, and a simplified and less expensive extravehicular visor assembly over the helmet. The liquid cooling garment was retained from Apollo, but umbilicals and astronaut life support assembly (ALSA) replaced backpacks for life support during space walks. Apollo-type spacesuits were used again in July 1975 when American astronauts and Soviet cosmonauts rendezvoused and docked in Earth orbit in the joint Apollo-Soyuz Test Project (ASTP) flight. Because no space walks were planned, U.S. crewmen were equipped with modified A7LB intra-vehicular Apollo spacesuits fitted with a simple cover layer replacing the thermal micrometeoroid layer. Information and Photos provided by NASAModified Extracts from This New Ocean: A History of Project MercuryBy Loyd S. Swenson Jr., James M. Grimwood, and Charles C. Alexander