U.S. astronaut Alan Shepard poses in his silver pressure suit in a 1963 picture from the early days of NASA's Mercury space program. Thursday marks the 50th anniversary of Shepard becoming the first American in space, when he completed a short suborbital voyage aboard the Freedom 7 spacecraft.
Over the decades, the U.S. space suit has evolved as astronauts' duties have become more complicated. The suit Shepard wore during his 16-minute flight was designed by aerospace manufacturer B.F. Goodrich. Called the Mark-IV, it was essentially a converted Navy-pilot suit, said Bill Ayrey, a space suit historian with ILC Dover in Delaware.
"Although it was referred to as a space suit by many at the time, it was actually a modified pressure suit," Ayrey said. "When they were looking for a space suit for Mercury, they were just looking for a suit that would hold pressure, in case they lost pressure aboard the capsule."
Later space suits, intended to withstand life outside the spacecraft, also kept astronauts well ventilated and at a comfortable temperature as well as safe from radiation and micrometeorite impacts.
Photograph courtesy NASA
This "hard suit" made by Litton Industries in the early 1960s was designed to protect Apollo astronauts during lunar extravehicular activities—aka moonwalks. But the suit was ultimately scrapped by NASA in favor of a softer design made by ILC Dover.
Dubbed the Block III, the Litton suit's main downside was that it was very bulky and could not be stored away under the seats on the trips between Earth and the moon, said ILC Dover's Ayrey. Adopting the hard suit, he said, "would have called for a much different vehicle than the Apollo Command Module, which had very limited space on board."
The hard suits did have one advantage over the soft suits: "When in use and pressurized, the hard suits did not compress as did the soft, fabric suits," Ayrey explained.
"So in terms of physics, the air did not compress while under pressure, thus resulting in less effort on the part of the astronaut when bending the various joints, such as [in] the arms and legs."
Photograph by Mark Avino, Smithsonian National Air and Space Museum
First "True" U.S. Space Suit?
Gemini 3 crew members Virgil "Gus" Grissom (left) and John Young pose in their G3C space suits in 1964. The boxes attached to the NASA suits are portable air conditioners, to keep the astronauts from overheating in their pressurized garments.
Developed by the David Clark Company, the G3C and its close cousin the G4C were designed with spacewalks and other extravehicular activities in mind, Ayrey said. "That's when you really start talking true space suits," he said.
The outer coverings of both David Clark suits consisted of multiple layers of nylon and a flame-resistant material called Nomex. Although the Gemini 3 crew didn't leave the orbiter, Gemini 4 astronaut Ed White performed the first U.S. spacewalk (picture) in 1965 while wearing the G4C space suit.
Photograph courtesy NASA
Giant Leap for Space Suits
Wearing an A7L-model space suit—as did most of the NASA astronauts who walked on the moon—astronaut Edwin "Buzz" Aldrin pauses for a picture during his historic walk on the lunar surface during the Apollo 11 mission in 1969.
Later, when the Apollo 15 astronauts were tasked with exploring the moon in a lunar rover, NASA switched to a slightly more flexible version of the A7L called the A7LB, explained Ayrey of ILC Dover, which made the A7L space suits.
"The astronauts needed to sit in the lunar rover … ," Ayrey said, "and the A7L suit wasn't good at flexing at the waist."
Underneath the familiar white cover of the A7LB space suit were intricate inner layers that protected astronauts from the harsh conditions of space.
In addition to multilayer insulating fabric, NASA's A7LB suit contained a liquid cooling system to prevent astronauts from overheating. Such a system was first adopted during the Apollo era, when it was discovered that simply circulating cool air through a suit was not sufficient, ILC Dover's Ayrey said.
"Our Apollo suit was the first time that you used a liquid cooling garment, or LCG, to pull body heat out [of the suit] and take the warm water into a backpack and chill it," he said.
NASA astronaut Bruce McCandless floats against a backdrop of blue seas and white clouds in an April 1983 photograph taken during a flight of the space shuttle Challenger. Equipped with a handheld controller for a maneuvering thruster, McCandless made the first spacewalk without being tethered to a shuttle.
Overall, the shuttle missions required a complete rethink of the space suit, ILC Dover's Ayrey said. "All suits have to be a little different. ... You don't take a Volkswagen off-the-road racing," he said. "You have to have that special vehicle. It's the same with space suits."
The Apollo space suits were designed to work in low-gravity environments and, as a result, they had flexible torsos, ankles, and knees for full-body mobility. This was less of an issue for the space shuttle suits, which were designed for zero-g work that requires mobility in only the upper body, for the most part.
The shuttle suits were also the first to be built with a modular design philosophy, Ayrey said. "We build [different parts of the suit] and ship them out to Houston, where the suit can be assembled for a mission and then brought back and disassembled and reused over and over again."
As NASA contemplates a return to the moon and eventually a mission to Mars, engineers are rethinking the space suit once again. Above, a model poses in a skintight space suit designed to protect astronauts but be more flexible.
Designed by MIT engineer Dava Newman, the sleek "BioSuit" does away with traditional gas pressurization. Instead the suit relies on mechanical counterpressure, which involves wrapping tight layers of material around the body. The BioSuit is not yet ready for space travel, but Newman predicts a working prototype could be ready in about ten years. (See more BioSuit pictures.)
ILC Dover's Ayrey is skeptical, however. "Theoretically it would permit an astronaut to maintain the pressure they need in the vacuum of space," he said. "But it is impractical, as I see it, because there are too many other challenges—such as heat retention and rejection—along with other factors that need to be addressed due to the hostile environment of space.
"This would all contribute to added layers, thus reducing the benefits gained."
Photograph courtesy Douglas Sonders; designed by Dava Newman/MIT and Guillermo Trotti/Trotti and Associates