How do space suit textiles work?

Have you ever wondered how a space suit is put together and how space suit textiles and materials work? Space always inspires wonder and this is an engaging activity for your students to learn about materials and their properties.

A spacesuit consists of several separate components and layers. Each one is made out of specialised synthetic materials, all of which do their own unique job in providing comfort and a breathable atmosphere with oxygen. So there is a lot of chemistry involved in ensuring that astronauts survive away from the protective atmosphere of the Earth. Before we explore the materials, it is a good starting point to look at what a space suit must do.

What must a space suit do? 

• Provide a stable internal pressure 
• Permit mobility for carrying out tasks
• Supply oxygen and eliminate carbon dioxide
• Regulate temperature between sunlight and shadow
• Shield against solar radiation

Diagram of a space suit 

Modern space suits are off the peg, the parts are interchangeable and assembled as a kit to fit each astronaut. So let’s take a journey through how the astronaut dresses for space and the chemistry involved in each step.

The cooling layer

The first layer an astronaut puts on is the cooling layer, essentially the undergarment. It is made of a stretchy material called Spandex. This layer also contains water hoses to regulate the astronauts temperature and reduce moisture from per during the long hours of strenuous work they undertake.

Spandex is a long chain polymer, with unique elastic properties but can recoil back to its original shape. It is made up of 2 segments, long amorphous strand, with a random molecular structure, and short, rigid strands. These strands combine to make the fibers soft. When force is applied rigid bonds are broken, and the amorphous strand is stretched, and once force is removed the amorphous strand returns to its relaxed state.

The space suit

Next up on the astronaut dressing list is the space suit itself, It consists of various layers, with each one performing a different function.

Firstly, the astronaut puts on the inside bladder, which is filled with gas and holds the oxygen to enable the astronaut to breathe. This layer is constructed of Polyurethane-coated nylon. The layer of polyurethane is added to nylon for its water resistant properties, it also makes the fabric more robust and critically, airtight, to prevent leakage of gases.

A further layer, the restraint, holds the bladder layer in place and moulds it to the correct shape of the astronauts body. This layer is constructed from polyester fabric and is sewn from patterns just like everyday clothin

A ripstop layer is next and is what it says, a tear resistance layer, to protect the rest of the suit and provide structural integrity.

Several layers are used as insulation, made from a material called Mylar. Mylar is a type of polyester film, made from molten PET (polyethylene terephthalate), the material has excellent insulation properties to allow body heat to be retained within the suit and has a high tensile strength. 

The white outer layer is made to reflect the sunlight and is manufactures using 3 different threads, all of which have a different function.

• Teflon provides water resistance. Teflon is a high performance fluoropolymer, this means it has a high molecular weight, it is this high molecular weight that makes it extremely water resistant.  
• Nomex is for fire resistance. Nomex is a long chain polyamide, it has a less rigid chain than Kevlar, which give it a more textile like property but retain the flame- resistant properties.
• The final material is the same material as used in bullet proof vests, Kevlar. Kevlar is composed of benzene rings, which are responsible for its high thermal stability, which make it extremely flame resistant.

An astronauts gloves are made in a similar way, yet have to allow joint mobility and gripping for working and picking up objects, as well as keep their hands warm. 

Hard upper body case 

The astronaut then puts on the hard upper body case, which is made from fiberglass, a tough but lightweight material.

Fiberglass, is made from glass, like a window, but rather than blowing or pouring the molten glass into shape, it is poured through a very small hole to create a fiber, resin is then added to the fiber to make a hard but lightweight material, that is strong enough to support the rest of the components of the space suit.

This part of the spacesuit is sleeveless, but fits over the astronauts body and connects the inside of the suit with the portable life support system, and the flexible parts of suit, which consist of the arms and legs.

Life support system

The life support system is attached to each individual astronaut, to allow maximum mobility during space walks and to allow the astronaut to individually control their own internal environment.

It contains oxygen for the astronaut's breathing, as well as a regulator to keep the suit at the correct pressure and a fan to circulate oxygen and remove carbon dioxide which the astronaut has exhaled. It also prevents the helmet from fogging up due to the astronaut’s respiration.

Also within the backpack is water for the cooling garment, a chiller for the water and a pump to circulate the water.  

Helmet

Last of all, the astronaut puts on their helmet. An astronaut's helmet is spheroidal dome, which allows for a wide field of view, pressure compensation and low weight. It even has a small foam block for the astronaut to scratch their nose! 

To protect the astronaut against the sun's solar radiation, the visor has a special gold coating, which has excellent properties to reflect infrared and ultraviolet, yet still lets in visible light.

Learn more about how space suit textiles and materials work

If you have any questions about how space suit textiles and materials work, please contact our Technical Support Team via techsupport@philipharris.co.uk