At its most basic, a spacesuit is meant to perform two nearly incompatible functions: protect the astronaut from the harsh environment of space, and allow the wearer to maneuver and work comfortably.
“The emphasis is on trying to develop a very mobile system while pressurized,” said Mr. Kosmo, who in 1961, fresh out of college with a degree in an aeronautical engineering, was asked if he’d be interested in a job described as working on “spacesuits, whatever they are.”
A pressure suit — a rubber bladder and a sealed helmet — allows the astronaut to survive in the vacuum of space. But a bladder is constricting when unpressurized, and when it is inflated movement becomes even more difficult, because moving the joints reduces the volume, increasing the pressure inside.
“When you pressurize it, it’s like working inside of a sausage,” said Joseph P. Kerwin, an astronaut aboard the Skylab mission in 1973 and the Apollo program “suit guy” — the astronaut who worked most closely with spacesuit engineers — for several years before that. “The whole trick in designing a spacesuit was to make it easier to move the joints inside that inflated balloon.”