From Mary Bellis,
Your Guide to Inventors.
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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 NASA's 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. Space walking 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 loss--an 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.