What Is an Astronaut Suit Called? | Beyond “Spacesuit”

The “astronaut suit” is most commonly called a spacesuit, but NASA’s formal name for the spacewalk suit is the Extravehicular Mobility Unit (EMU).

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Ask most people what an astronaut wears, and they’ll say “spacesuit.” That’s not wrong, but it’s only half the story. NASA actually uses different names for different suits depending on the mission phase. The suit you wear inside a spacecraft during launch is not the same one you wear outside on a spacewalk, and neither is the one planned for walking on the Moon. Each serves a distinct purpose, and each has its own official designation. Understanding the difference between the EMU, xEMU, and OCSS matters more than memorizing a single name.

The Suit for Spacewalks: The EMU

When you picture an astronaut floating outside the International Space Station (ISS), you’re looking at the Extravehicular Mobility Unit, or EMU. NASA has used this suit design for ISS spacewalks for more than 40 years, with its roots in the Space Shuttle Program of the 1980s. It’s built for Extra-Vehicular Activities (EVAs) — the official term for spacewalks — and it’s a modular system that can be assembled to fit different body sizes.

The Suits for the Moon and Orion: xEMU and OCSS

For upcoming Artemis missions aiming to return humans to the Moon, NASA developed new suit technology. The Exploration Extravehicular Mobility Unit (xEMU) was designed for lunar surface spacewalks. When NASA publicly unveiled this suit on Oct. 15, 2019, the agency described it as the suit that would be worn by the first woman and next man exploring the Moon. It includes upgrades for mobility and dust resistance compared to the older EMU.

The bright orange suit you see astronauts wearing inside the Orion spacecraft is a completely different piece of equipment. NASA calls it the Orion Crew Survival System (OCSS). It’s designed for launch day, emergency situations, high-risk parts of lunar missions, and the high-speed return to Earth. Critically, it is worn inside Orion, not for spacewalks. Treating every suit as interchangeable is the most common mistake.

How a Spacesuit Actually Works

NASA describes a spacesuit as “a miniature spaceship shaped like a human body.” It has two main parts: the pressure garment and the life support system. The pressure garment maintains a livable atmosphere around the body, while the life support system supplies breathable oxygen and removes the carbon dioxide you exhale. It also protects against the vacuum of space, extreme temperature swings, and damage from space dust and micrometeoroids.

This is why NASA emphasizes that a fully equipped suit is effectively a one-person spacecraft — it’s life-support equipment, not clothing. While the EMU handles the ISS, and the OCSS handles Orion, the Russian-built Orlan spacesuit is the other type used on the ISS.

Apollo astronauts of the 1960s and 70s wore suits that were “basically a one-piece” design, custom tailored for each moonwalker. The modern approach is modular, offering more flexibility for a wider range of astronauts.

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FAQs

Is the Orion launch suit used for spacewalks?

No. The Orion Crew Survival System is worn only inside the Orion spacecraft during launch, reentry, and emergencies. NASA explicitly designed it for those high-risk phases, not for extravehicular activity. The xEMU is the suit designated for Moon surface walks, while the EMU handles ISS spacewalks.

Why does NASA have multiple types of spacesuits?

NASA separates suit types by mission phase because the demands differ. A launch suit must handle cabin depressurization and high-speed landings, while a spacewalk suit must provide mobility and life support in a vacuum. The OCSS, EMU, and xEMU each optimize for their specific environment, which is why using one name for all of them misses the point.

What is the main difference between the EMU and the xEMU?

The EMU has served the Space Shuttle and ISS programs since the 1980s, built for orbital spacewalks. The xEMU is the newer design created for Artemis lunar missions, announced in 2019. NASA designed the xEMU with better mobility for walking on the Moon’s surface and improved protection against abrasive lunar dust, which the orbital EMU doesn’t need to handle.