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History of the Spacesuit - A Pressure Situation

Scientists working on the first aviation programs understood that on Earth, pressure is exerted in all directions. Scientists also knew that pressure decreases at higher altitudes.

Both of these facts enable humans to breathe normal air—made up of oxygen, nitrogen and other gases—at sea level with no side effects. When atmospheric pressure changes, our bodies must compensate for the difference or we must provide some mechanical assistance to breathe and to perform.

The scientists for the United States Navy used this information and created a pressurized suit for their jet pilots. To help keep a flier’s body under the proper amount of pressure at high altitudes, the Navy created a two-layer suit. The inside layer was a bladder—or soft container—for pure oxygen. This inside layer would apply pressure all around the pilot’s body. The outside layer was made of aluminized nylon and that was used to restrain the bladder to prevent it from blowing up like a balloon!

This technology was adapted for the first pressurized spacesuit.

The Mercury Spacesuit — The First Pressurized Spacesuit

The Mercury program was the first American man-in-space program. This program focused on orbiting spacecrafts around Earth, studying man's ability to function in space and recovering astronauts and their spacecraft safely.

The Navy’s suit design was adapted into the first American spacesuit suit. The Mercury astronauts wore the suits unpressurized. In the event of an emergency, the suits could be inflated. Unfortunately, these pressurized suits made it somewhat difficult to bend at the joints. These joints were only made of fabric. Every time they tried to bend their arms, the fabric would fold in on itself and this in turn would slightly increase the pressure within the suit.

Luckily for the astronauts who flew during the six flights of the Mercury program, cabin pressure was never lost and the suits never had to be inflated.

 

Gemini Spacesuits — The First EMU

During the era of the Gemini program, engineers were faced with a new design challenge. How could they adapt the suit so that it could be used as an Extravehicular Mobility Unit (EMU) for spacewalking or as an escape suit in case the astronauts ever had to be ejected from their spacecraft?

The answer was clear. They had to use a new combination of materials that would allow for pressurization and mobility. They replaced the fabric joints with bladders that simulated human joints. Nylon netting around the bladders restricted their size and pressure. This meant more mobility while the suit was pressurized and more comfort while the suit was depressurized.

The first person to use this suit as an EMU was Edward White, II. On June 3, 1965, White left the Gemini 4 space capsule and spent half an hour tumbling and rolling in space. He moved around using a hand-held propulsion gun that activated jets of nitrogen when the trigger was pulled. He remained connected to his spacecraft by his oxygen-feed hose, which also served as his communications link.

From this experience and that of other astronauts, design engineers learned that it was difficult for astronauts to move in space. They also learned that they needed to find a way to keep the astronauts cool inside their suits, and to find a way to keep their visors from fogging up.

Apollo Spacesuits—Made for the Moon

The new EMUs had to be designed so that the astronauts could walk on the moon. A few things needed to be taken into consideration. First, the Moon’s environment is harsh. Its surface is jagged and is constantly being hit by micrometeoroids (fast moving bits of rock).

Second, astronauts needed to be able to roam freely, so having a tether was not an option! Third, the moonwalkers needed to be able to bend so they could pick up samples from the moon. Because of the Apollo program’s goal, the Apollo EMU was the first one designed specifically for extravehicular activities (EVA)—activities taking place outside of the spacecraft.

To accommodate all of these needs and to solve the problems posed by the Gemini suit, the scientists designed a number of parts. They created a fitted garment that looked like long johns laced with plastic tubing. Cool water circulated through the tubing to help keep the astronauts cool while they were working.

To solve the mobility problem, scientists set out to build a portable life support system so astronauts would not have to remain connected to their spacecraft. They also replaced some of the materials in the suit. The pressure layer and its restraining layer were still part of the design, but the joints were replaced with rubber ones that were pleated—somewhat like an accordion. These were covered by layers of materials that were flame- and micrometeoroid-resistant.

They also changed the helmet. The original helmets were fitted to an astronaut’s head and would therefore move when the head moved. The Apollo helmet was a plastic pressure helmet that the head could move freely in. An additional visor, fitting over the helmet, was created to protect astronauts from the harmful rays of the Sun.

Finally, they changed the gloves and the boots so they could be used on the Moon’s surface. The gloves featured rubber fingertips so that the astronauts could still have some sense of feeling when getting samples or adjusting equipment.

Today’s Suit

The suit used today is designed specifically for EVA’s. That’s because many crews will be helping to assemble, construct, and maintain the International Space Station over the next decade.

The suits are made of heavy-duty materials to protect the astronauts while they work in space. They’re also designed to provide the basic necessities of life.

We went to the research lab to learn more about the EMU.

 

Suit up and let’s go!

• Basic Parts of the EMU
• Suiting up for a Spacewalk
• Donning a Spacesuit
• Materials Used to Build the EMU