The Spacesuit: A History of Personal Spacecraft

The Indispensable Garment

The spacesuit is one of the most iconic symbols of human exploration, yet it is often misunderstood as mere clothing. In reality, a spacesuit is a marvel of engineering—a custom-fitted, anthropomorphic spacecraft. When an astronaut ventures outside the protective confines of a capsule or space station, the suit must provide every life-sustaining function of the vehicle it left behind. It is a self-contained world, a personal spaceship designed to shield a fragile human body from the lethal vacuum of space.

The fundamental challenges of surviving in space dictate the core functions of any suit. It must maintain a stable internal pressure, creating an artificial atmosphere around the astronaut. Without this pressure, the low boiling point of bodily fluids in a vacuum would cause them to vaporize, a fatal condition known as ebullism. The suit must supply a steady stream of breathable oxygen while actively removing the carbon dioxide produced by the astronaut’s own metabolism. It has to manage extreme temperatures, insulating the wearer from the searing heat of direct sunlight and the cold of deep shadow, which can swing by hundreds of degrees. Finally, it must offer protection against the invisible threats of solar radiation and the physical danger of micrometeoroids—tiny particles traveling at orbital velocities that can strike with the force of a bullet.

To meet these diverse needs, spacesuits have evolved into two primary categories. Intravehicular Activity (IVA) suits are lighter, more comfortable garments worn inside a spacecraft. Their main purpose is to act as a final layer of protection, a personal lifeboat in the event of an emergency like a sudden cabin depressurization. In contrast, Extravehicular Activity (EVA) suits are the heavy-duty workhorses of space. These are the complex, multi-layered systems with life support backpacks that enable astronauts to perform spacewalks, construct space stations, and explore other worlds. This article traces the remarkable evolution of these personal spacecraft, from their earliest conceptual origins in high-altitude flight to the advanced systems being designed today for humanity’s return to the Moon and the eventual journey to Mars.

The Pioneers: Early Pressure Suits and the First Steps into Space

The journey to creating a functional spacesuit began decades before the first rockets breached the atmosphere. The initial challenge was not the vacuum of space but the thin, frigid air of Earth’s upper stratosphere, a realm that pushed the limits of both aviation and human physiology.

High-Altitude Precursors

As early as the 1930s, individual inventors and aviators recognized the need for a pressurized garment to survive at extreme altitudes. In 1931, Soviet inventor Evgeniy Chertovsky developed a full-pressure suit he called a “skafandr,” a term derived from the Greek for “boat-man” that is still used in Russia for both diving suits and spacesuits. A few years later, in 1935, Spanish engineer Emilio Herrera designed a sophisticated “stratonautical space suit” for a planned high-altitude balloon flight. While the flight was canceled due to the outbreak of the Spanish Civil War, his design featured a microphone, a breathing system, and articulated joints.

In the United States, aviator Wiley Post famously experimented with a series of pressure suits to enable his record-breaking high-altitude flights. His work, in collaboration with B.F. Goodrich designer Russell Colley, produced some of the first practical pressure suits in America. In Italy, Lieutenant Colonel Mario Pezzi wore a semi-rigid pressurized suit during a record-setting altitude flight in 1938. These pioneering efforts, driven by the demands of aviation, established the fundamental principles of pressure-suit design and laid the essential groundwork for the garments that would one day travel into orbit.

The Soviet Vostok and Voskhod Programs

When the space race began in earnest, the Soviet Union took an early lead, and its spacesuit development reflected a philosophy of rapid, milestone-driven innovation.

The SK-1 suit became the first spacesuit worn by a human in space when Yuri Gagarin launched on his historic flight on April 12, 1961. It was an IVA suit, designed primarily as a safety system for the Vostok program. The Vostok capsule’s design required the cosmonaut to eject at an altitude of about 7 kilometers (23,000 feet) and descend to Earth under a separate parachute. The SK-1 was essential to survive this high-altitude ejection. Weighing 20 kg (44 lbs), the suit operated with vehicle-supplied life support and maintained an internal pressure of 3.9 to 4.4 psi. A nearly identical version, the SK-2, was tailored for women and was worn by Valentina Tereshkova, the first woman in space, in 1963.

Building on this success, the Soviets quickly adapted the design for an even more ambitious goal: the first spacewalk. The Berkut suit, a modified SK-1, was developed for the Voskhod 2 mission in 1965. For this flight, the suit was paired with a backpack life support system, the KP-55, which provided about 45 minutes of oxygen for extravehicular activity. The total system weighed 41.5 kg (91.5 lbs) and operated at a higher pressure of 5.8 psi to provide a more robust buffer against the vacuum.

On March 18, 1965, Alexei Leonov donned the Berkut suit and exited his Voskhod 2 spacecraft, becoming the first human to float freely in space. The triumph, however, nearly turned to tragedy. In the vacuum, his suit inflated and became unexpectedly rigid, a phenomenon known as “ballooning.” When it was time to return, Leonov found he was too stiff and bulky to fit back through the narrow, inflatable airlock. With his oxygen supply dwindling, he made a perilous decision. Without consulting mission control, he manually opened a valve to bleed pressure from his suit, reducing it to a lower, emergency level. This made the suit flexible enough for him to squeeze headfirst into the airlock, a move that violated procedure and required him to perform contortions that left him dangerously overheated and exhausted.

Leonov’s life-threatening struggle was a stark lesson in the unforeseen complexities of working in space. It revealed that a spacesuit was not just a pressure garment but a complex machine whose dynamics could be dangerously unpredictable. This incident also highlighted a key difference in the early design philosophies of the two superpowers. The Soviet approach prioritized achieving “firsts,” often by rapidly modifying existing hardware. The Berkut, a direct descendant of an IVA suit, was pushed into an EVA role, and the risks inherent in this rapid adaptation became terrifyingly clear.

The American Mercury and Gemini Programs

In contrast, the American approach to spacesuit development was more methodical and incremental, building upon a strong foundation of military aviation research.

America’s first spacesuit, used for Project Mercury, was a direct adaptation of the U.S. Navy’s Mark IV high-altitude pressure suit. Developed by the B.F. Goodrich Company, the suit was modified for NASA by replacing its open-loop breathing system with a closed-loop one, which circulated oxygen for cooling before venting it. Its dark gray nylon shell was swapped for a layer of aluminized nylon to reflect the intense heat of the sun. It was a pure IVA suit, intended only as a backup in case the Mercury capsule lost pressure. Weighing just 10 kg (22 lbs) and operating at 3.7 psi, it was a lightweight and relatively simple garment.

The subsequent Gemini Program required a far more advanced suit. The missions were longer, and for the first time, American astronauts would leave their spacecraft. The G4C suit, developed by the David Clark Company, was a major leap forward. It was designed to be more comfortable for long-duration flights of up to 14 days and was engineered from the outset for EVA. When Ed White performed the first American spacewalk on the Gemini 4 mission in June 1965, he wore a G4C suit. For spacewalks, the suit was augmented with extra protective layers; the EVA configuration was composed of up to 21 layers of material, compared to just four for the standard intravehicular version. Weighing 15.4 kg (34 lbs) in its EVA configuration, the G4C maintained an operating pressure of 3.7 psi and featured dedicated umbilical ports for oxygen, liquid cooling, and biomedical data transmission. The Gemini suit represented a deliberate, systems-engineering-focused step toward a true EVA capability, a philosophy that would reach its zenith in the next chapter of space exploration.

The Giant Leap: Suits for the Lunar Surface

Walking on the Moon required more than just a pressure suit; it demanded a self-contained, personal spacecraft. The Apollo spacesuit was precisely that—a complex, integrated system that gave astronauts the freedom to explore another world, untethered from their lander. This iconic white suit became the enduring symbol of humanity’s greatest exploratory achievement.

The Apollo A7L and A7LB

The Apollo suit, officially known as the Extravehicular Mobility Unit (EMU), was a complete system comprising two main parts: the Pressure Suit Assembly (PSA), the suit itself, and the Portable Life Support System (PLSS), the famous “backpack” that kept the astronauts alive. The development was a massive collaborative effort, with International Latex Corporation (ILC Dover), a company with expertise in making rubber girdles for its parent company Playtex, building the flexible suit, and Hamilton Standard providing the complex life support backpack. Following the tragic Apollo 1 fire in 1967, the suit was significantly upgraded with fire-resistant materials and given the designation A7L.

The suit was a masterpiece of materials science. Its outermost layer, the Integrated Thermal Micrometeoroid Garment (ITMG), consisted of 13 layers of specialized fabrics. These included an inner rubber-coated nylon, multiple layers of super-insulating aluminized Mylar and Dacron, and an outer layer of woven, Teflon-coated Beta cloth, a fireproof material. This layered shield protected the astronaut from temperature swings from 121 °C (250 °F) in sunlight to -157 °C (-250 °F) in shadow, and from the threat of micrometeoroids. For added durability, patches of a woven nickel-chrome metal fabric called Chromel-R were placed on the gloves, the boots, and the area of the torso where the backpack would rub against the suit.

Mobility, a major challenge in a pressurized suit, was achieved through the use of convoluted, bellows-like joints made of molded rubber at the shoulders, elbows, hips, and knees. However, the most critical innovation for working on the Moon was the Liquid Cooling Garment (LCG). This was a full-body undergarment, a mesh “union suit” with a network of fine plastic tubes woven into it. Cool water, supplied by the PLSS, circulated through these tubes, absorbing the astronaut’s body heat and carrying it back to the backpack, where a device called a sublimator vented it into space as water vapor. This system was essential for preventing overheating during strenuous lunar excursions.

The entire Apollo EMU, with its suit and life support backpack, weighed approximately 91 kg (200 lbs) on Earth. In the Moon’s one-sixth gravity, however, it felt like a more manageable 14 kg (30 lbs). The suit operated at an internal pressure of 3.7 psi of pure oxygen.

For the final three Apollo missions (15, 16, and 17), an upgraded version called the A7LB was introduced. This new model featured two crucial improvements for the extended missions that used the Lunar Roving Vehicle (LRV). A new joint at the waist allowed astronauts to sit comfortably in the rover, a feat that would have been impossible in the earlier A7L. A redesigned neck joint also provided greater up-and-down and sideways visibility, which was vital for driving on the lunar surface.

The Apollo suit represents a paradigm shift in design. It was no longer just a pressure garment but a fully integrated, multi-system platform—a hub connecting the human to a host of technologies. The PLSS provided independent life support, the LCG managed thermal control, the “Snoopy Cap” worn under the helmet handled communications, and a suite of biomedical sensors monitored the astronaut’s health. Even non-engineering needs were integrated into the design. Starting with Apollo 13, the mission commander’s suit was adorned with red stripes on the arms, legs, and helmet. This was a direct response to a request from NASA‘s public affairs office to help the media and the public easily distinguish between the two white-suited figures on the Moon. By the Apollo era, the spacesuit had matured into a microcosm of the entire space program—a complex, expensive, and highly integrated system designed to accomplish a singular, monumental goal.

The Workhorses: Suits for the Space Station Era

With the end of the Apollo program, the focus of human spaceflight shifted from lunar exploration to long-duration missions in low-Earth orbit. This new era required a new kind of spacesuit: a reusable, serviceable workhorse designed for the routine assembly and maintenance of spacecraft like the Space Shuttle and the International Space Station (ISS). The two major space powers, the United States and Russia, developed distinct solutions that reflected their different operational needs and design philosophies.

The American Extravehicular Mobility Unit (EMU)

Designed for the Space Shuttle program and still in use on the ISS, the American EMU represents a significant departure from the custom-fitted suits of the Apollo era. Its defining characteristic is modularity. The heart of the suit is the Hard Upper Torso (HUT), a rigid, one-size-fits-all vest made of fiberglass. Arms, legs, and gloves are produced in a variety of sizes and can be attached to the HUT to assemble a suit that fits a specific astronaut, whether male or female. This modular design is highly cost-effective for a long-term program with a large and diverse astronaut corps, as a smaller inventory of interchangeable parts can be used to outfit many different people.

The EMU has been the backbone of American spacewalks since its first use in 1982. It has enabled astronauts to perform hundreds of EVAs, including the repair of the Hubble Space Telescope, the capture and repair of satellites, and the complex, multi-year assembly of the International Space Station. The complete EMU assembly, including its life support system, weighs between 125 kg (275 lbs) and 145 kg (319 lbs), depending on its configuration. It operates at an internal pressure of 4.3 psi and can support a spacewalk for up to 8.5 hours. Its tough outer layer is made of a material called Ortho-Fabric, a blend of Gore-Tex, Kevlar, and Nomex, providing excellent protection against tears and abrasion.

The Russian Orlan and Sokol Suits

Russia’s primary EVA suit, the Orlan, follows a different design philosophy, prioritizing robust simplicity and in-space operational efficiency. Its origins trace back to the Krechet, a suit that was being developed for the canceled Soviet lunar program. The Orlan is a semi-rigid suit, combining a hard torso and helmet with flexible arms and legs.

Its most distinctive feature is its rear-entry design. The entire life support backpack is integrated into a hatch on the back of the suit. To don the suit, a cosmonaut simply opens the hatch, backs into the suit as if climbing into a small cockpit, and closes the door behind them. This allows for quick donning, in as little as five minutes, without any assistance from another crew member. The Orlan has been continuously upgraded over the decades, evolving from the Orlan-D first used on the Salyut 6 space station in 1977 to the modern, computerized Orlan-MKS used on the ISS today. The latest models are fully self-contained and feature an onboard computer that monitors suit systems and provides diagnostic information on an LCD screen. The Orlan-MKS weighs about 110 kg (240 lbs) and operates at a higher pressure of 5.8 psi. This higher pressure reduces the “pre-breathe” time that crew members must undergo to purge nitrogen from their blood, making it more efficient to prepare for a spacewalk.

In a separate category is the Sokol suit. This is not an EVA suit but a lightweight IVA “rescue suit.” Its development was a direct and somber response to the Soyuz 11 tragedy in 1971, when a crew of three cosmonauts died after their capsule depressurized during reentry. They were not wearing suits at the time. Since that incident, every crew launching on a Soyuz spacecraft has worn a custom-fitted Sokol suit during the critical phases of flight: launch, docking, and landing. Weighing only 10 kg (22 lbs), the Sokol is designed for a single purpose: to keep the crew alive in the event of a cabin pressure leak.

The contrast between the American EMU and the Russian Orlan provides a fascinating case study in how operational philosophies shape technology. The EMU’s modularity is a product of NASA‘s logistical needs for a large astronaut corps over a long-duration program. The Orlan’s one-piece, rear-entry design prioritizes speed and efficiency for the crew in orbit. The existence of the separate Sokol suit further highlights the Russian approach of using highly specialized tools for specific jobs—a lightweight suit for launch and entry, and a heavy-duty suit for EVA.

Comparative Table of Key Spacesuits

The following table summarizes the key specifications for the major spacesuits discussed, allowing for a direct comparison of their designs and capabilities.

A New Age of Spaceflight: Modern and Commercial Suits

The 21st century has ushered in a new era of spaceflight, characterized by the rise of new national space programs and the powerful entry of commercial companies. This diversification has led to a corresponding boom in spacesuit development, with new designs that reflect modern technologies, different operational philosophies, and a changing market.

China’s Feitian Suit

As China emerged as a major spacefaring nation, it developed its own EVA capability. Its first EVA suit, the Feitian (meaning “flying in the sky”), is a clear example of building on proven technology. In the early 2000s, China purchased several Orlan suits from Russia, which served as the foundation for their domestic program. Like the Orlan, the Feitian is a semi-rigid, rear-entry suit. The first generation was worn by taikonaut Zhai Zhigang during China’s inaugural spacewalk in 2008.

Today, a second-generation Feitian suit is in use on the Tiangong space station. While visually similar to its Russian predecessor, the Feitian incorporates significant modern upgrades. It features more advanced digital technology, with improved communications systems and data displays, and its joints are designed to be more flexible. Weighing approximately 120-130 kg (260-286 lbs), the suit is designed to support an eight-hour spacewalk, demonstrating that China has not only mastered EVA technology but is now iterating and improving upon it.

The Commercial Crew IVA Suits

The advent of NASA’s Commercial Crew Program, which contracts with private companies to ferry astronauts to the ISS, has spurred the development of a new generation of IVA suits where functionality is blended with modern design and user experience.

Boeing’s “Starliner Blue” suit, developed for its CST-100 Starliner spacecraft, is a prime example. Manufactured by the venerable David Clark Company, the suit prioritizes astronaut comfort and mobility. It is approximately 40% lighter than previous American IVA suits and features a distinctive blue color that serves as a powerful branding element. Practical innovations include touchscreen-compatible gloves, breathable boots, and strategically placed zippers in the torso that make it easier for astronauts to move and transition from a seated to a standing position within the capsule.

SpaceX‘s IVA suit, worn by astronauts on the Crew Dragon, has become iconic for its sleek, futuristic aesthetic. This is a deliberate choice, reflecting the company’s focus on creating inspiring technology. The suit is a custom-fitted, single-piece garment designed to be fully integrated with the spacecraft’s seat through a single umbilical connection—a “suit seat system.” This umbilical provides cooling air, emergency pressurization gas, and communications. The suit features a 3D-printed helmet, a flame-resistant outer layer, and touchscreen-compatible gloves, blending cutting-edge manufacturing with a design sensibility that looks as if it came from a science fiction film.

The First Commercial EVA Suit

Pushing the boundaries even further, SpaceX evolved its stylish IVA suit into a fully functional EVA suit for the Polaris Dawn mission, which conducted the first-ever private spacewalk in 2024. This required a host of significant upgrades. New, more flexible joints were incorporated to improve mobility under pressure. The helmet was fitted with a new visor coated externally with copper and indium tin oxide to manage thermal loads and reduce glare. A key innovation is an integrated heads-up display (HUD) inside the helmet, which provides the astronaut with real-time data on suit pressure, temperature, and humidity.

This development signals a shift in the market. For the first time, design drivers for spacesuits include not just technical performance but also branding, aesthetics, and user experience. Most importantly, the SpaceX EVA suit was engineered with scalability and mass production in mind, a direct reflection of the company’s long-term goals of establishing bases on the Moon and Mars. This represents a move away from the traditional model of bespoke, handcrafted suits toward a new philosophy focused on manufacturing efficiency. This “democratization” of suit design is enabled by modern technologies like advanced materials and 3D printing, allowing for faster development and a focus on manufacturability that was secondary in the government-led programs of the past. The spacesuit is becoming a product, not just a piece of mission hardware.

The Future: Returning to the Moon and Beyond

As humanity sets its sights on returning to the Moon and eventually journeying to Mars, the development of next-generation spacesuits has become a critical focus. The challenges of long-duration surface exploration demand suits with unprecedented mobility, durability, and technological integration. The approach to creating these future suits, however, is evolving just as rapidly as the technology itself.

NASA’s Artemis Program: A New Commercial Model

For the Artemis program, NASA has adopted a new procurement strategy. Instead of designing and owning the suits in-house, the agency is contracting with commercial partners to provide “moonwalking services.” Under this model, NASA sets the technical and safety requirements, and the companies design, build, own, and maintain the suits. This approach is intended to foster a competitive commercial market for spacesuit technology and services, providing NASA with flexibility and redundancy.

Axiom Space’s AxEMU was selected for the first task order to develop the suit for the Artemis III lunar landing. The Axiom Extravehicular Mobility Unit (AxEMU) is not being designed from scratch; it builds upon years of research and development from NASA’s own Exploration Extravehicular Mobility Unit (xEMU) prototype program. The AxEMU is specifically designed for the harsh environment of the lunar south pole, with its extreme cold and long shadows. A primary focus is on dramatically improved mobility. The suit incorporates advanced joints in the arms and legs to allow astronauts to walk more naturally, kneel down to inspect rocks, and handle tools with far greater dexterity than was possible in the stiff Apollo suits. Another key requirement is sizing; the AxEMU is being designed to fit a much wider range of body types, accommodating at least 90 percent of the American male and female population. In a unique collaboration that highlights the new commercial era, Axiom has partnered with the Italian luxury fashion house Prada to design the suit’s outer layer, blending high-tech materials with advanced design and manufacturing expertise. The suit will also be equipped with modern avionics, including an HD camera and 4G/LTE communication capabilities.

Advanced Concepts and Technologies

While the Artemis suits represent a pragmatic evolution of existing technology, researchers are also exploring revolutionary concepts for the more distant future. The most promising of these is the Mechanical Counter-Pressure (MCP) suit. Instead of using a bubble of pressurized gas to protect the astronaut, an MCP suit would apply pressure directly to the skin using a tight, elastic garment made of advanced materials.

In theory, this could solve the greatest challenge of all current EVA suits: the inherent stiffness caused by gas pressure. An MCP suit could offer a dramatic increase in mobility and flexibility, allowing for movements as natural as wearing a wetsuit. It would also be significantly lighter and less complex than a traditional gas-pressurized suit. The concept has been investigated since the 1960s with prototypes like the Space Activity Suit, but formidable engineering challenges remain. The primary difficulty is ensuring that the suit provides perfectly uniform pressure over the entire surface of the body, as any gaps could lead to serious injury.

The path forward for spacesuit development is therefore a dual one. For the near-term goal of returning to the Moon, the approach is evolutionary, with companies like Axiom and Collins building upon decades of NASA research to create improved, but conceptually familiar, gas-pressurized suits. This pragmatic strategy lowers risk and accelerates the timeline. In parallel, the continued investigation into revolutionary concepts like the MCP suit represents a long-term vision. This research addresses the fundamental physical limitations of today’s suits and could be essential for the high-mobility, long-duration EVAs that will be required for the eventual human exploration of Mars. This dual-track approach—improving what works now while researching what will be necessary later—is the hallmark of a mature and forward-thinking technology program, paving the way for the next generation of explorers.

Summary

The spacesuit has undergone a remarkable transformation over more than six decades of human spaceflight. It began as a simple adaptation of high-altitude aviation pressure suits, serving as a last-resort safety device for the first astronauts and cosmonauts. With the dawn of the space race, it rapidly evolved. The Soviet Berkut and American Gemini suits enabled the first tentative steps outside a spacecraft, revealing the challenges of working in a vacuum. The Apollo A7L marked the technology’s coming of age, becoming a true personal spacecraft that allowed humans to walk on another world. In the decades that followed, the American EMU and Russian Orlan became the reliable, reusable workhorses of the space station era, facilitating the construction and maintenance of our orbital outposts.

Today, we stand at the threshold of a new age. The rise of China’s Feitian suit and the entrance of commercial companies like Boeing and SpaceX have diversified the field, introducing new design philosophies driven by modern manufacturing, user experience, and even aesthetics. Looking ahead, the Artemis program is pushing development further, with commercial partners like Axiom Space and Collins Aerospace creating suits with unprecedented mobility and technological integration for a new generation of moonwalkers.

Throughout this journey, the core challenges have remained constant: the delicate balance between protection and mobility, the complex management of pressure and temperature, and the absolute necessity for reliable life support. The future of the spacesuit will be defined by innovations in materials science, advanced manufacturing like 3D printing, and revolutionary concepts such as mechanical counter-pressure. These next-generation suits will not only enable humanity to return to the Moon but will be essential tools for establishing a sustained presence there, and for taking the next giant leap to Mars and beyond.