Spacesuits are built from roughly 14 layers of different materials, each serving a specific purpose: blocking radiation, stopping micrometeoroid impacts, insulating against temperature swings of over 500°F, and keeping breathable air sealed inside. The result is essentially a wearable spacecraft, and almost every layer uses a different fabric or composite chosen for one job.
The Outer Shell: Ortho-Fabric, Kevlar, and Mylar
The outermost portion of a spacesuit is called the Thermal Micrometeoroid Garment, or TMG. Its job is to absorb impacts from tiny debris particles traveling at thousands of miles per hour and to reflect extreme heat and cold. The outer surface is made of Ortho-Fabric, a tightly woven blend of Gore-Tex, Kevlar, and Nomex. Kevlar provides puncture and tear resistance (the same material used in bulletproof vests), Nomex adds flame resistance, and Gore-Tex helps repel dust and liquids.
Beneath that outer layer sit multiple sheets of aluminized Mylar, a thin reflective film that acts like a thermos. Each layer reflects radiant heat from the sun and traps warmth on the cold side, where temperatures in shadow can plunge to roughly minus 250°F. Newer TMG designs also incorporate a layer of silicone rubber loaded with microscopic tungsten particles, which adds impact absorption without significant bulk or weight.
Research into next-generation TMG materials has explored replacing traditional neoprene-coated nylon with woven aramid textiles infused with shear-thickening fluids, liquids that stiffen instantly on impact. This approach improves cut and puncture resistance while keeping the garment flexible during normal movement.
The Pressure Layer
Underneath all that protective armor is the layer that actually keeps the astronaut alive: a bladder of airtight material that holds pressurized oxygen against the body. In NASA’s Extravehicular Mobility Unit (the white suits used on the International Space Station), this bladder is made of polyurethane-coated nylon. It functions like a balloon, maintaining roughly 4.3 psi of pressure so the astronaut’s blood doesn’t boil in the vacuum of space.
Surrounding the bladder is a restraint layer made of Dacron, a strong polyester fabric. Without it, the pressurized bladder would inflate into a rigid balloon shape, making it impossible to bend arms or legs. The Dacron layer limits how far the bladder can expand, giving the suit its recognizable human shape and allowing some degree of movement.
Cooling From the Inside
Pressed directly against the astronaut’s skin is the Liquid Cooling and Ventilation Garment, a full-body undergarment threaded with roughly 300 feet of narrow Tygon tubing. Cold water circulates through these tubes to pull heat away from the body. Without this system, an astronaut working in a sealed, insulated suit would overheat within minutes.
The garment itself is made of spandex-nylon mesh, stretchy enough to stay in contact with skin across the torso, arms, and legs. Ventilation channels woven into the fabric also move air across the body to manage humidity and carry away carbon dioxide toward the life support system in the backpack.
The Helmet and Visor
Spacesuit helmets use a hard shell of high-impact polycarbonate, the same family of plastics found in motorcycle visors and aircraft canopies. Polycarbonate is optically clear, extremely impact-resistant, and light enough to keep the helmet manageable. Some earlier designs, like those from the Gemini program, used fiberglass and epoxy resin for the shell structure.
The sun visor that flips down over the face is coated with a microscopically thin layer of gold. Gold is one of the best reflectors of infrared radiation, so this coating blocks intense solar glare and heat without significantly reducing visibility. The gold layer is thin enough to see through but reflects enough energy to protect the astronaut’s eyes and face from unfiltered sunlight, which in space is far more intense than on Earth’s surface.
Joints and Mobility
A pressurized suit naturally resists bending, so the joints are some of the most engineered parts of the design. Hard joints at the hips, shoulders, and waist use aluminum alloy or stiff composite materials shaped into bearing rings that rotate smoothly under pressure. These bearings let astronauts twist and reach without fighting against the suit’s internal air pressure.
Softer joints at the elbows, knees, and fingers use fabric-based designs made of nylon and layered textiles arranged in bellows-like folds. These accordion patterns allow bending while keeping the suit sealed. The gloves are among the most complex components, with silicone rubber fingertips for grip and multilayer insulation thin enough to preserve some sense of touch.
Fire-Resistant Layers
Because spacesuits operate in oxygen-enriched environments where fire risk is elevated, several layers incorporate inherently flame-resistant fibers. Nomex, a heat-resistant aramid fiber developed by DuPont, appears in both the outer shell and inner structural layers. Some suit components also use PBI (polybenzimidazole), a synthetic fiber that resists ignition and has been rated as one of the most thermally protective fabrics tested in military and aerospace applications. PBI does not melt or drip when exposed to flame, making it particularly useful in the oxygen-rich atmosphere inside a sealed suit.
What Artemis-Era Suits Are Adding
The newest suits being developed for NASA’s Artemis lunar missions, including the AxEMU designed by Axiom Space in collaboration with Prada, build on the same core material categories but push further on flexibility and sizing. The outer layer still relies on Nomex, Kevlar, and Mylar, but the textiles are engineered with modular sizing systems so a wider range of body types can wear them comfortably.
Lunar surface suits face challenges the ISS suits don’t. Moon dust is abrasive, electrostatically charged, and fine enough to work into seams and joints. Designers are developing tighter weaves and dust-resistant coatings for the outer fabric layers. The AxEMU is also built for up to eight hours of continuous use outside, with a fully redundant life support system, meaning every material in the suit has to perform reliably over long stretches in the harsh conditions of the lunar south pole, where temperatures and lighting are more extreme than at equatorial landing sites used during Apollo.