The EMU is NASA's spacewalk suit, a hard torso with soft limbs and a life support backpack of its own.
nasa-iss-emu-spacesuit The Extravehicular Mobility Unit, or EMU, is the suit NASA astronauts wear for Space Shuttle and International Space Station spacewalks. Hamilton Sundstrand and ILC Dover built it. It has a hard torso and soft arms and legs, and a backpack of its own supplies oxygen and cooling water and removes carbon dioxide.
The suit's soft parts are built from layers of fabric and film. The outer cover is Ortho-Fabric, which resists abrasion and tears and protects against micrometeoroids, tiny fast-moving particles. Five layers of aluminised Mylar insulate beneath it. The hard upper torso is fibreglass, and the helmet is clear polycarbonate.
The suit worn by NASA astronauts for Space Shuttle and International Space Station spacewalks. It combines a fibreglass hard upper torso, a polycarbonate helmet and fabric arms and legs with a backpack that supplies oxygen, cooling water and carbon dioxide removal.
The thermal micrometeoroid garment, or TMG, is the suit's outer cover. Its fabric, called Ortho-Fabric, has an outer face of Gore-Tex and an inner face of Nomex and Kevlar. Beneath it lie five layers of aluminised Mylar and a neoprene-coated nylon liner.
Under the TMG, the arms, lower torso and legs have a Dacron restraint layer and pressure bladders of urethane-coated nylon. About one eighth of an inch separates the TMG liner from the restraint layer. Together the TMG and restraint layers form a Whipple shield, a spaced barrier against fast-moving particles.
The hard upper torso, or HUT, is a fibreglass shell. It is the structural mounting point for the helmet, arms, lower torso and life support. The helmet bubble is clear polycarbonate, and the visor assembly adds polycarbonate, fibreglass, a polysulfone sun visor and stainless steel plates.
The liquid cooling and ventilation garment circulates cooling water through tubing near the skin. The tubing is ethylene vinyl acetate, woven through a nylon and spandex stretch fabric, with a nylon tricot liner. Vent ducts run in tunnels of nylon and spandex mesh covered with Teflon fabric.
The Phase VI glove has a urethane bladder, protected from abrasion by a two-layer Teflon liner. The palm of the glove's outer layer is a Vectran knit shaped in 3-D and coated with RTV 3145 silicone. The boots have a fibreglass sole stiffener.
A fibre of expanded Teflon, used on the outer face of the Ortho-Fabric cover.
The inner face of the Ortho-Fabric cover, woven as a ripstop.
Five layers of insulation in the outer cover, with a non-woven scrim, and more layers in the glove fingers.
The pressure bladders of the arms, lower torso and legs, heat-sealed into pressure vessels.
The hard upper torso shell, the front of the visor assembly shell, and the boot sole stiffener.
The clear helmet bubble, the back of the visor assembly shell and the protective visor.
Its backpack, the Primary Life Support Subsystem, is made up of four circuits: oxygen, water supply, cooling and ventilation.
Axiom Space
Indirect, via xEMU: NASA built the xEMU to advance the technologies of the current EMU
ILC Industries
Aluminized Mylar, 5 layers with non-woven scrim. Here: Insulation (MLI); Glove finger TMG insulation. There: Reflective insulation (Mylar).
Teflon. Here: Glove bladder abrasion liner; Glove finger TMG outer layer. There: Teflon cloth layer.
Neoprene-coated nylon ripstop. Here: TMG liner. There: Inner liner; Bladder.
North American Aviation
Fiberglass. Here: HUT shell; EVVA shell (front portion) and more. There: Thruster outer wrap.
Stainless steel. Here: Shell attachment plates. There: Outer shell (heat shield structure); VHF scimitar antennas and more.
NPP Zvezda / Roscosmos
Clear polycarbonate. Here: Helmet bubble; EVVA shell (back portion) and more. There: Helmet; Double-pane primary helmet window with protective glass (Orlan-M design) and more.
Dacron. Here: Restraint layer. There: Load-bearing (restraint) layer of the soft shells (Orlan-M design).
TRW
Fiberglass. Here: HUT shell; EVVA shell (front portion) and more. There: Radiation heat shield spacer.
Stainless steel. Here: Shell attachment plates. There: Pintle tip, original; Flow-control valve bellows and more.
Public descriptions of the suit do not give its total mass, the date of its first flight or the materials inside the backpack. Also unnamed are the resin in the fibreglass, the grades of polycarbonate and stainless steel, and the layer of the cover between the Ortho-Fabric and the insulation.
What is written above is built from these numbers and quotes. Each row links to the page it was taken from. Get all of it as JSON, or ask our MCP server.
| What | Value |
|---|---|
| Operating suit pressure | 4.3 psid |
| EVA duration requirement | 7 hours maximum (6 hours under worst-case solar exposure) |
| TMG insulation | 5 layers of aluminized Mylar |
| Gap between TMG liner and restraint | about one eighth inch |
| Ortho-Fabric temperature range | −184.4 to 149 C |
Each material named in the sources: where it is used here, which other products use it, and its key numbers when its material page exists.
Used in 4 partsPressure bladder · Arm assemblies bladder · Lower torso and leg bladders · +1 more
Used in 3 partsHelmet bubble · EVVA shell (back portion) · Protective visor
Used in 3 partsHUT shell · EVVA shell (front portion) · Boot sole stiffener
Used in 2 partsInsulation (MLI) · Glove finger TMG insulation
Used in 2 partsRestraint (outer stretch fabric) · Vent duct tunnels
Used in 2 partsGlove bladder abrasion liner · Glove finger TMG outer layer
Used in 1 partRestraint layer
Used in 1 partCooling water tubing
Used in 1 partCenter and side eyeshades
Used in 1 partOuter cover face (Ortho-Fabric)
Used in 1 partTMG liner
Used in 1 partOuter cover inner face (Ortho-Fabric)
Used in 1 partLiner
Used in 1 partSun visor
Used in 1 partGlove TMG palm coating
Used in 1 partShell attachment plates
Used in 1 partGlove bladder
Used in 1 partGlove TMG palm
NASA data book and NTRS papers name the soft goods, HUT, helmet, visors, LCVG and glove materials; the PLSS backpack parts have no stated materials.
| Part | Material | Finish and standard | Made by |
|---|---|---|---|
| Outer cover face (Ortho-Fabric)“an outer face comprised of 400 denier Gore-Tex” | Gore-Tex (expanded Teflon) fibre, outer face of Ortho-Fabricortho-fabric-gore-tex-face | — | — |
| Outer cover inner face (Ortho-Fabric)“an inner face of 200 Denier Nomex (Dupont) and 400 denier Kevlar” | Nomex and Kevlarortho-fabric-nomex-kevlar-face | — | — |
| Insulation (MLI)“5 layers of aluminized mylar” | Aluminized Mylar, 5 layers with non-woven scrimaluminized-mylar | — | — |
| TMG liner“Neoprene coated nylon ripstop” | Neoprene-coated nylon ripstopneoprene-coated-nylon | — | — |
| Part | Material | Finish and standard | Made by |
|---|---|---|---|
| Restraint layer“The Restraint layer, made of dacron” | Dacrondacron-polyester | — | — |
| Pressure bladder“made from urethane/nylon laminate” | Urethane/nylon laminateurethane-coated-nylon | — | — |
| Arm assemblies bladder“pressure vessels made of heat sealed, urethane-coated, nylon bladder” | Urethane-coated nylonurethane-coated-nylon | — | — |
| Lower torso and leg bladders“The Bladders are fabricated from urethane coated nylon oxford fabric” | Urethane-coated nylon oxford fabricurethane-coated-nylon | — | — |
| Part | Material | Finish and standard | Made by |
|---|---|---|---|
| HUT shell“It is made of a fiberglass shell.” | Fiberglass (resin not stated)fiberglass | — | — |
| Part | Material | Finish and standard | Made by |
|---|---|---|---|
| Helmet bubble“It is made of a clear polycarbonate.” | Clear polycarbonatepolycarbonate | — | — |
| EVVA shell (back portion)“The back portion of the Shell is formed from a polycarbonate sheet” | Polycarbonate sheetpolycarbonate | — | — |
| EVVA shell (front portion)“The front part of the Shell is made of fiberglass” | Fiberglassfiberglass | — | — |
| Shell attachment plates“attached to the main Shell by stainless steel plates” | Stainless steel (grade not stated)stainless-steel | — | — |
| Protective visor“The Protective Visor is formed from a polycarbonate sheet.” | Polycarbonate sheet, hard-coated, thin internal coatingpolycarbonate | — | — |
| Sun visor“movable polysulfone Sun Visor” | Polysulfonepolysulfone | — | — |
| Center and side eyeshades“movable fiberglass/epoxy Center and Side Eyeshades” | Fiberglass/epoxyfiberglass-epoxy | — | — |
| Part | Material | Finish and standard | Made by |
|---|---|---|---|
| Restraint (outer stretch fabric)“consisting of a nylon spandex blend” | Nylon/spandex blendnylon-spandex | — | — |
| Liner“nylon tricot fabric which feels” | Nylon tricotnylon-tricot | — | — |
| Cooling water tubing“ethylene vinyl acetate tubing woven through the spandex restraint cloth” | Ethylene vinyl acetateethylene-vinyl-acetate | — | — |
| Vent duct tunnels“Tunnels made of nylon/ spandex mesh covered with a Teflon fabric for abrasion resistance” | Nylon/spandex mesh covered with Teflon fabricnylon-spandex | — | — |
| Part | Material | Finish and standard | Made by |
|---|---|---|---|
| Glove bladder“The Phase VI glove bladder is made of urethane material” | Urethaneurethane | — | — |
| Glove bladder abrasion liner“A Teflon liner (dual layer) provides abrasion protection to the bladder” | Teflon (dual layer)teflon-fabric | — | — |
| Glove TMG palm“Vectran knit which is stretched and compressed into the 3-D shape of the palm” | Vectran knit with silicone coatingvectran-knit | — | — |
| Glove TMG palm coating“The palm is then coated with RTV 3145” | RTV 3145 siliconesilicone-rtv-3145 | — | — |
| Glove finger TMG outer layer“outer layer of Teflon fabric over multiple layers of unreinforced aluminized Mylar” | Teflon fabricteflon-fabric | — | — |
| Glove finger TMG insulation“non-woven Dacron spacer material to prevent thermal shorting” | Aluminized Mylar with non-woven Dacron spaceraluminized-mylar | — | — |
| Boot sole stiffener“fiberglass sole stiffener” | Fiberglassfiberglass | — | — |
| Boot sizing inserts“constructed from foam rubber and urethane coated nylon fabric” | Foam rubber and urethane-coated nylon fabricurethane-coated-nylon | — | — |
| Part | Material | Finish and standard | Made by |
|---|---|---|---|
| PLSS backpack (oxygen, feedwater, cooling and ventilation circuits)“made up of four distinct circuits” | Not said | — | Item 100 |
PLSS component materials, total mass, first flight not sourced.
CubeSats in a P-POD dispenser Maker credit: NASA (suit built by Hamilton Sundstrand / ILC Dover). Collected from public pages and documents, checked 4 Nov 2026.
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