How NASA space suits have changed, from Project Mercury to the cutting-edge Mark III

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Aug 15, 2016

Looking back at the technology of the 1960s and 1970s, it’s amazing what humanity was able to accomplish during the golden years of the Space Race. The Apollo capsules and space shuttles understandably got most of the attention — but the gear that actually kept the astronauts alive is just as interesting.

So, where did we start, and where are we going?

To track the history of the space suit, you have to go all the way back to the 1930s and 1940s, when the U.S. military was trying to figure out a way to keep its pilots conscious and alive while flying turbocharged jets capable of reaching high altitudes where the air is too thin and cold to travel unprotected. Those early models — including the first practical design, the S-1 Henry Suit — were essentially built into the aircraft and used it for oxygen and air. These were fine for flying planes, but the National Advisory Committee for Aeronautics (NACA), NASA's predecessor, needed something a bit more ambitious to dive into the space race.

So, the Mercury space suit was born. A variation of the Navy Mark IV, the Mercury suit is the iconic silver, full-body, high-altitude space suit (man, that thing is still sexy) worn by the astronauts during all the manned Project Mercury missions. The suit was actually developed for use in high-altitude airplanes, but NASA co-opted it for the Mercury missions and made a few tweaks for space flight.

The biggest change? Replacing the dark gray nylon outer shell with the retro-future aluminum-coated nylon, which looked much cooler (and also helped with thermal control). They also coated the leather boots (yes, leather boots) with aluminum. The suits were individually tailored for each astronaut, in case you’re wondering how they pulled off that fitted look. The suit underwent a few upgrades during the Mercury era, including the addition of a urine collection device, after astronaut Alan Shepard was forced to urinate in the suit due to lengthy countdown delay. Eek.

These suits were arguably the coolest space suits NASA ever put in the air, but sadly, they were also the least practical.

After the Mercury missions, NASA cranked up development on suits designed specifically for use in space, which most notably started to feature fully functional pressure and temperature regulation systems. Put simply: Humans are not built to function in space. At all. So, NASA had to develop suits capable of independently maintaining pressure for the astronaut inside (essentially creating a suit-sized habitat) and regulating temperature (which can vary from -249 degrees Fahrenheit to as hot as 250 degrees Fahrenheit, depending on the sun’s location).

The first step in that direction was the Gemini suit, which was actually worn by astronaut Ed White during the first American space walk on June 3, 1965. It was a precursor to the big, puffy white suits we know and love — along with the Apollo suits made famous in all those Neil Armstrong pics on the lunar surface. The Gemini suit was the first NASA suit actually designed for use inside, and outside, a spacecraft. 

NASA used the experience to gather information from the Gemini missions to better hone the space suit designs for future missions (hey, at this point, we still hadn’t even gotten to the moon yet!). NASA even developed a (rather bulky) independent Extravehicular Life Support System (ELSS) for the Gemini suits, but that tech was never actually used for an EVA. As the space agency started prepping for the Apollo missions, they chose a later version of the Gemini suit as a model to build on. 

With designs on the moon, NASA set to design one of its most (and arguably still the most) ambitious suits yet: The Apollo A7L space suit. They were initially using an upgraded Gemini suit model for Apollo, but after the tragic Apollo I fire that killed all three crew members, NASA upgraded the materials to be more fire-resistant. Instead of just having to plan for the harsh environment of space itself, engineers also had to make a suit that could keep a human alive on the moon — while also letting them walk and move around enough to explore and collect samples.

That’s where the classic “fishbowl” helmet design came from, to allow an unobstructed view for the wearer, and the suit was also designed for more mobility around the joints. The main Apollo design was a one piece, five-layer "torso-limb" suit with joints made of synthetic and natural rubber at the shoulders, elbows, wrist, hips, ankle, and knee joints. To keep the wearer safe, the suit featured an Integrated Thermal Micrometeoroid Garment (ITMG) using 13 layers of material to protect from radiation and micrometeroids. The suit was stacked with rubber coated nylon, five layers of aluminized Mylar, four layers of nonwoven Dacron, two layers of aluminized Kapton film/Beta marquisette laminate, and Teflon coated Beta filament cloth. An upgraded version of the Apollo suit was later used for the Skylab missions, as well.

Once the Apollo initiative wrapped, NASA didn’t have much use for a suit designed to explore an alien world, so they developed the “pumpkin suit,” aka the Advanced Crew Escape Suit (ACES), which was used for launch and reentry for the shuttle missions. NASA started using it in the early 1990’s, and have been using a version ever since. The suit includes integrated pressure bladders, its own ventilation system, and black leather paratrooper-style boots with zippers designed to prevent ankle injuries (and reduce swelling when the suit is pressurized).

With no new suit ready at this point, NASA is planning to use an upgrades ACES suit for the upcoming Orion missions. There’s also the Extravehicular Mobility Unit (EMU), which NASA uses on the ISS for space walks. It’s not super-mobile, but you can fly around in it and work on the space station, so it has its uses.

So, what does the future hold for astronauts in the next few decades? There are a boatload of cool concepts floating around out there (we’re quite partial to the sweet BioSuit being developed by an MIT professor, FWIW), and any of those could certainly get us to the stars — but NASA seems fairly keen on its Mark III concept. Likely best know for some Tron-style design work in the early prototypes, the Mark III is the outfit NASA is hitching its space exploration ambitions upon for Mars and beyond.

The Mark III is intended to help develop and test new tech for future planetary exploration, and serves as a rear-entry suit that crew members can climb into through a hatch (a concept that got its start in sci-fi, not surprisingly). This suit would also be the most versatile ever conceived, and would actually allow astronauts enough range of motion to actually kneel down and pick up objects (unlike the Apollo suits). The suit is modular, comprised of soft and hard components, which should help with mobility and not tired out astronauts as quickly as the Apollo suits. The current incarnation weighs a whopping 201 pounds (including the support backpack). 

One of the coolest aspects of the Mark III is that it features 8.3 pounds per square inch operating pressure, making it a ”zero-prebreathe" suit, which means astronauts would be able to transition directly from a mixed-gas space station environment (i.e. the ISS) straight to the suit without risk of the bends. Current suits require several hours of time to reduce pressure to prevent astronauts from getting the bends, so again, the Mark III is a huge step up.

Early testing of the Mark III is extremely promising, and even with the increased weight, wearers were capable of bending down to pick up objects and move around. Some testers note the Mark III actually features “almost shirtsleeve-equivalent mobility,” which could be a killer asset when you’re already trying to navigate the Martian surface and not trip over all the red rocks. It may not be as sexy as the suit donned by Matt Damon in The Martian, but if it’ll keep us alive and mobile enough to explore, it should still be a huge step in that direction.