How to Make a Spacesuit
ESA astronaut Tim Peake in his EVA suit check. Credit: ESA

How to Make a Spacesuit

14/04/2021Written by Alex Thompson

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Orlan DMA EVA Spacesuit on display at the National Space Centre

When you imagine an astronaut, you will probably picture them in a large cumbersome spacesuit, similar to those worn by the Apollo-era space explorers, but there are all manner of garments worn by astronauts today, to travel, live and work in space.

As plans are put in place to return humans to the Moon and possibly on to Mars, the suits being created to sustain life and protect us from the harsh realities of these environments look like science fiction becoming fact.

The National Space Centre has many spacesuits on display, including one of the most successful spacesuit designs ever, the iconic Orlan EVA (extra vehicular activity – spacewalk) spacesuit.

These “miniature spacecraft” spacesuits are made up of between 13 and over 20 layers of protection.

Top Layer – Ortho-Fabric

Top Layer – Ortho-Fabric
Astronaut Bruce McCandless on First-ever Untethered Spacewalk Credit: NASA

The top layer of an EVA suit has two main functions; to protect against the intense heat of the Sun, but also to safeguard the wearer from micro-meteoroids.

Modern spacesuits use an outermost layer of Othro-Fabric to combat these, using a blend of Nomex, Gore-Tex and Kevlar, which is also used in the manufacture of bullet proof vests.

Micro-meteoroids can travel up to 17,500mph in space, so tough and resistant materials are crucial for the protection of the spacesuit and astronaut within.

Another barrier used as thermal protection is actually the colour of the suits, as white reflects the Sun’s heat, as well as making the astronaut more visible against the blackness of space.

Mylar

Mylar
Cross-section of layers in space suit construction Credit: NASA

With little to no atmosphere, the temperature on a spacewalk can vary wildly. When facing the Sun an astronaut has to endure heat of over 120°C, whilst, when it is blocked by the Earth, it can drop as low as -170°C.

As the International Space Station (ISS) takes 90 minutes to orbit the Earth, as astronaut on a spacewalk outside the station can experience both of these extremes throughout sessions that can last many hours. This is where the Mylar layer will become vital to the construction on the spacesuit and the protection of the astronaut.

Mylar is a form of polyester used to make heat-resistant film and sheets. You will often see it given to runners during long endurance races, or to protect people recovering from shock.

It is very good at regulating temperature, meaning it can help keep an astronaut at the correct temperature, even in the extremes of space.

There are several layers of this material just below the Othro-Fabric.

Ripstop and Bladder Layers

Ripstop and Bladder Layers
Full Pressure Space Suit. Credit: San Diego Air and Space Museum Archive

Below the Mylar is normally a ripstop layer, a woven fabric made of nylon that uses a special reinforcement technique to stop it tearing and ripping. This is used to protect the Mylar above it and the other layers beneath it, known as the bladder.

The main bladder layer is a coated nylon filled with gas to help keep the astronaut’s body at the correct pressure.

Without pressure the gasses in our blood would boil, we’d begin to inflate and probably lose consciousness within half a minute. The bladder prevents this.

There is a secondary bladder layer of Dacron between this and the ripstop to keep the main bladder layer in the correct shape around the astronaut’s body.

Cooling Garment

Cooling Garment
Liquid cooling and ventilation garment for the Space Shuttle/International Space Station Extravehicular Mobility Unit (EMU). Credit: NASA

With over a dozen layers protecting you, it can began to feel a little warm, so the three layers closest to the astronaut’s skin keep the body cool, including a Spandex layer.

Spandex is a stretchy material that allows another layer made of tubing to be woven into it. The tubing carries cold water around the suit and cools the body inside. Some modern suits will even take sweat from the body and turn it into cold water to be pumped through the tubes.

A final layer of nylon tricot is placed between the skin and tubing to make the astronaut comfortable and that completes an EVA suit.

Maximum Absorbency Garment

Maximum Absorbency Garment
Maximum Absorbency Garment. Credit: Smithsonian

Though not technically a part of the EVA suit, it would be amiss to not mention another very important clothing item the astronauts put on before the suit.

As anyone who has ever been caught short in a meeting or long drive can attest, Mother Nature has a habit of calling at the most inopportune moments. This is where the Maximum Absorbency Garment comes in – effectively a really big nappy.

Consisting of coform absorbent material and a water absorbent layer, this is the most effective way for an astronaut to relieve themselves on an EVA.

As spacewalks can last several hours the garment may be used more than once, and if needed could take solid waste as well as liquid – although that would certainly make the rest of the spacewalk slightly less comfortable for the astronaut.