What is the Boeing Starliner IVA Suit?

Intra-Vehicular Activity Suits

When people imagine a spacesuit, they typically picture the bulky, white, backpack-equipped ensemble an astronaut wears to walk on the Moon or perform a spacewalk outside the International Space Station. That is an Extra-Vehicular Activity (EVA) suit, a self-contained personal spacecraft. The Boeing Starliner suit is something different. It’s an Intra-Vehicular Activity (IVA) suit, designed exclusively for wear inside the spacecraft during the most dynamic phases of a mission: launch, docking, and re-entry.

A modern spacecraft like the CST-100 Starliner is a “shirt-sleeve” environment. During the nine-to-five of a space mission, astronauts work in comfortable clothing, just as they would in a laboratory on Earth. The cabin provides pressurized, breathable air, and a stable temperature. The IVA suit, in this context, is not a garment for daily wear. It is a form-fitted, personal lifeboat.

The primary purpose of any IVA suit is to protect an astronaut from a catastrophic loss of cabin pressure. While spacecraft are built with extreme redundancy, a micrometeoroid strike or a seal failure could, in a worst-case scenario, let the precious internal atmosphere vent into the vacuum of space. This is an event called depressurization. An unprotected human would lose consciousness in seconds. The IVA suit is designed to automatically detect this pressure drop, instantly inflate, and provide the astronaut with their own bubble of pressurized air.

This suit also serves a second, related purpose: protecting the crew from a toxic atmosphere. A fire on a spacecraft, for example, wouldn’t just be a thermal threat; it would fill the cabin with smoke and chemical fumes. A leak in a coolant line, such as one carrying ammonia, could also make the air unbreathable. In such an event, an astronaut can seal the suit’s helmet and switch to a dedicated air supply, breathing safely while they work to resolve the emergency or return to Earth.

The Starliner suit is a highly specialized piece of safety equipment. It is the astronaut’s last line of defense, engineered to function perfectly in the worst possible scenarios. Its design must balance this extreme survivability with the practical needs of the crew. An astronaut wearing it must still be able to pilot the vehicle, reach controls, and communicate effectively. This tension between protection and mobility is the central challenge in designing any IVA suit.

The Starliner Program and the Need for a New Suit

The story of the Boeing Starliner suit begins with the end of the Space Shuttle program. After the final shuttle, Space Shuttle Atlantis, touched down in 2011, NASA found itself without a domestic vehicle capable of launching its own astronauts into orbit. For nearly a decade, the United States relied exclusively on its international partner, Russia, purchasing seats on the Soyuz spacecraft to ferry crews to and from the International Space Station.

To end this reliance and foster a new commercial space industry, NASA initiated the Commercial Crew Program. This was a fundamental shift in how the space agency operated. Instead of owning and operating its own vehicles as it did with Apollo and the Space Shuttle, NASA would purchase “taxi” services from private companies.

In 2014, NASA selected two companies to develop these new crew transportation systems: SpaceX, with its Crew Dragon capsule, and Boeing, with its CST-100 Starliner capsule.

This new program meant that for the first time, companies other than a government space agency were responsible for designing an entire human-rated space system from the ground up. This included the rockets, the capsules, the launch pad procedures, and, of course, the spacesuits. NASA provided a long list of safety and performance requirements that had to be met, but the specific design was left to the companies.

This clean-sheet approach gave Boeing an opportunity. The company wasn’t required to use NASA’s existing suit designs, such as the bulky orange Advanced Crew Escape Suit (ACES) worn by shuttle astronauts. Boeing could design a suit that was fully integrated with its specific spacecraft. The Starliner suit didn’t need to be compatible with any other vehicle; it only needed to be perfect for the Starliner.

This led to a new generation of IVA suits. Both SpaceX and Boeing moved away from the heavy, utility-focused “pumpkin suits” of the shuttle era. The new requirements called for suits that were lighter, more comfortable, and easier to move in. They needed to be usable by a wider range of body types and be intuitive to operate. The suit was no longer just a piece of safety gear; it was a core component of the Starliner’s modern, streamlined cockpit.

Design Philosophy and Development

To create its new-generation suit, Boeing did not start from scratch. It partnered with a company that has one of the deepest legacies in American spacesuit and pressure suit design: the David Clark Company.

The David Clark Company has been in the business of high-altitude protection for decades. Its engineers developed the pressure suits worn by pilots of the X-15 rocket plane in the 1960s. They built the iconic, mustard-yellow suits for the SR-71 Blackbird spy plane. Most famously, they were the prime contractor for the orange ACES that NASA astronauts wore during shuttle launches and landings.

With the Starliner suit, the David Clark Company was tasked with taking its decades of experience and applying it to a 21st-century set of problems. The new design philosophy prioritized three things: light weight, mobility, and comfort.

The old ACES suit was a marvel of engineering, but it was also heavy, weighing over 30 pounds without its parachute and survival gear. The Starliner suit, by contrast, weighs only about 12 pounds. This weight reduction is a significant quality-of-life improvement for the astronauts. It reduces fatigue during the long hours spent strapped into the launch vehicle and makes it easier to move, especially in the event of an emergency egress on the launch pad.

Mobility was another key driver. The Starliner capsule is a compact vehicle. Astronauts need to be able to climb into their seats, reach across the control panels, and twist their bodies to access switches. The new suit was built with flexibility in mind. Rather than using bulky, rigid joints, it incorporates flexible “accordion” joints at the elbows and knees. The materials themselves are lighter and less stiff than previous-generation suits.

Aesthetically, the suit marked a major departure. Boeing selected a unique, deep blue color, which quickly became known as “Boeing Blue.” This was a conscious branding decision, moving away from the high-visibility “International Orange” of the ACES suit. The logic had changed: the shuttle was a winged glider that could land on a runway, but it could also ditch in the ocean. The orange was for high visibility in a search-and-rescue operation at sea. The Starliner is a capsule designed to land on land (in the American West) or water, equipped with modern beacons. The need for a specific passive color was considered less important than creating a modern, distinct identity for the program. The blue suit became an instant icon for the Starliner.

A Head-to-Toe Analysis of the “Boeing Blue” Suit

The Starliner suit appears simple from the outside, but it is a complex, layered system where every component serves a specific function.

The Helmet

The most striking feature of the Starliner suit is its helmet. Unlike the hard-shell, two-piece “fishbowl” helmets of the Space Shuttle era, the Starliner helmet is a soft, integrated hood that zips directly onto the suit’s neck ring. This soft hood is part of the suit’s pressure bladder, and it moves with the astronaut’s head.

This design offers a huge advantage in visibility and mobility. An astronaut in a hard-shell helmet has to move their entire torso to look left or right. An astronaut in the Starliner suit can simply turn their head, just as they would normally. This is essential for a spacecraft pilot who needs to quickly scan instruments, look out the window, and communicate with the crew commander.

Attached to this soft hood is a large, clear polycarbonate visor. This visor provides a wide, unobstructed field of view. When the astronaut is working in a safe, pressurized cabin, the visor can be pushed up and kept open. In an emergency, the astronaut pulls the visor down, where it locks into the lower part of the helmet to form a perfect, airtight seal, protecting their face and providing breathing gas.

Underneath the helmet assembly, the astronaut wears a “comm cap,” a soft fabric cap with integrated microphones and earpieces for communicating with the crew and mission control.

The Main Torso and Layering

The suit’s main body is a sophisticated, multi-layer garment. The outermost layer is the “Boeing Blue” fabric. This layer is not just for looks; it is the suit’s first line of defense. It’s made from a fire-resistant material, similar to Nomex, that can withstand high temperatures and won’t catch fire in the high-oxygen environment of a spacecraft. This layer also provides scuff and tear resistance.

Beneath this blue exterior lies the functional heart of the suit. There are two primary inner layers.

1. The Pressure Bladder: This is an airtight layer, likely made of a urethane-coated nylon, that is designed to hold air. When the suit inflates during a depressurization, this is the layer that fills up like a custom-fitted balloon.
2. The Restraint Layer: A pressure bladder on its own would simply balloon into a useless sphere. The restraint layer is a fabric layer, often made of sturdy nylon, that is tailored precisely to the astronaut’s body. It fits over the bladder and controls its shape, ensuring that when the suit inflates, it inflates into the shape of a human, allowing the astronaut to still bend (with effort) at the knees and elbows.

The suit is donned using a series of airtight zippers. These zippers are a critical piece of technology themselves, as they must be able to open and close easily while maintaining a perfect pressure seal against the vacuum of space.

Gloves and Boots

Designing spacesuit gloves is one of the most difficult challenges in engineering. The human hand is a marvel of dexterity, and astronauts need that dexterity to flip switches, use tools, and, in a modern cockpit, operate touch screens.

The Starliner gloves are a significant advancement. They are designed to be tactile, allowing the astronaut to “feel” the controls they are touching. The material on the fingertips is specially designed to be compatible with the capacitive touch screens that make up the Starliner’s main control interface. This is a thoroughly modern feature that simply wasn’t a consideration for shuttle-era suits.

Like the rest of the suit, the gloves must also pressurize. When inflated, they become stiffer, and a great deal of design work has gone into pre-shaping them in a semi-curled position to make it easier for an astronaut to grip controls.

The boots are similarly lightweight and functional. They look more like high-top wrestling shoes than a traditional “space boot.” They are made of a combination of the blue suit material and a lightweight, durable sole. Their primary job is to provide a stable footing inside the capsule, interface with the foot restraints on the floor, and, importantly, form the pressure-tight seal for the astronaut’s feet, completing the “lifeboat” from head to toe.

Life Support and Connectivity

The Starliner IVA suit is not a self-contained system. It is a “parasitic” suit, meaning it relies entirely on the spacecraft for its life support. A single “umbilical” cable plugs into the astronaut’s seat.

This umbilical is a lifeline that provides several key functions:

• Breathing Air: It supplies a precise mix of oxygen and nitrogen for the astronaut to breathe.
• Pressurization: If the cabin pressure drops, it’s this umbilical that floods the suit with air to inflate it.
• Cooling: An astronaut inside a sealed suit, even an unpressurized one, can get very hot. The umbilical provides cooling ventilation, circulating air through the suit to remove excess heat and moisture.
• Communications: The electrical connections for the comm cap run through the umbilical, connecting the astronaut’s headset to the spacecraft’s communication system.

Safety Features

The entire suit is a collection of safety features. The fire-resistant outer layer protects against flash fires. The pressure system protects against hypoxia. The sealed visor and clean air supply protect against a toxic atmosphere.

One subtle but important feature is the suit’s modularity and sizing. Using a series of zippers and lacing gussets, the suit can be adjusted to fit a wide variety of body types. This is a departure from older suits that often had to be extensively custom-built for each astronaut. This modularity makes it faster and more cost-effective to prepare suits for a new crew.

How the Starliner Suit Functions in an Emergency

The Starliner suit sits dormant for 99% of its use. Astronauts wear it unpressurized, with their visors open, functioning as little more than a high-tech flight suit. Its true purpose is only revealed in an emergency.

Cabin Depressurization

This is the most dangerous scenario in low Earth orbit. If a micrometeoroid or piece of orbital debris punches a hole in the Starliner’s hull, the cabin air will rush out into the vacuum. This process can be fast or slow, but the outcome is the same: the air pressure drops to a level that cannot support human life.

The Starliner’s systems are designed to detect this. When the cabin pressure falls below a pre-set, hazardous level, the suit’s life support system, fed by the umbilical, automatically activates. It begins force-feeding air into the suit’s pressure bladder.

In seconds, the soft, flexible suit transforms. It inflates, becoming rigid and firm. The pressure inside the suit stabilizes at a level sufficient to keep the astronaut conscious and alive – typically around 3.5 psi. This is not the 14.7 psi of pressure we experience at sea level, but it’s enough pressure to prevent the astronaut’s body fluids from “boiling” (a phenomenon called ebullism) and to deliver enough oxygen to the lungs.

In this state, the astronaut’s life is saved, but their job becomes much harder. Moving inside a pressurized suit is like trying to move inside a stiff, air-filled balloon. Every bend of the elbow or knee requires fighting against the suit’s internal pressure. This is why the suit’s joint design is so important. The astronauts have trained for this scenario, and they know they will have limited mobility. Their priority becomes managing the emergency, sealing the leak, or preparing for an emergency return to Earth.

Toxic Atmosphere Response

A fire or chemical leak presents a different kind of threat. In this case, the cabin remains pressurized, but the air becomes poisonous. An astronaut would be alerted by smoke detectors or chemical sensors.

Their response would be simple and immediate. They would reach up and pull down their visor, locking it into place. This single action seals their head and face from the contaminated cabin. Simultaneously, the suit’s air system would begin feeding them a clean, safe breathing mix directly from the spacecraft’s tanks.

The rest of the suit would remain unpressurized and flexible, allowing the crew the full mobility needed to find the source of the fire, extinguish it, and scrub the atmosphere clean. The suit, in this mode, acts as a sophisticated gas mask, giving them the time and a clear head to solve the problem.

The Human Factor: Comfort, Mobility, and Utility

A spacesuit can be the most advanced piece of safety equipment in the world, but if it’s so uncomfortable or restrictive that the astronaut can’t do their job, it’s a failure. The “human factor,” or ergonomics, was a central part of the Starliner suit’s design.

Designing for Different Body Types

NASA’s astronaut corps is diverse, with men and women of a wide range of heights, weights, and body proportions. In the shuttle era, this often required creating many different suit sizes and expensive, custom-fitted components.

The Starliner suit was designed to be much more versatile. Instead of a single, fixed-size suit, it’s a modular system. An astronaut can be fitted with a specific-sized torso, and then attach arms and legs of a different size. The suit also features expansion gussets with zippers and lacing, allowing for fine-tuning the fit around the waist, chest, and limbs.

This approach makes it much easier to size a suit for a new astronaut, reducing the time and cost required to prepare for a mission. It also makes the suit more comfortable, as a better fit reduces chafing and “hot spots” where the suit might bunch or pinch.

Operating Vehicle Controls

The Starliner suit’s mobility is a key feature. When unpressurized, it’s designed to be as unobtrusive as possible. The lightweight materials and flexible joints allow the astronaut to reach all the necessary controls, including the overhead panels and the side-stick controllers used to fly the spacecraft.

The touch-screen-compatible gloves are perhaps the best example of this user-centric design. The CST-100 Starliner cockpit is not the “knobs and dials” cockpit of the Space Shuttle. It’s a modern “glass cockpit” dominated by large, programmable display screens. The ability to interact with these screens while wearing a pressurized glove is a non-negotiable requirement.

The soft-hood helmet also plays a role. It allows the astronaut to wear prescription glasses, which is not possible with some close-fitting helmet designs. The wide field of view lets them maintain situational awareness without feeling like they are looking through a periscope.

Long-Duration Wear

Astronauts don’t just “throw on” their suits moments before launch. They begin the suiting-up process hours before they even walk to the launch pad. They then sit, strapped into their seats, for several more hours as the rocket is fueled and pre-launch checks are completed. The entire “wear time” for a single launch or re-entry sequence can easily exceed 10 or 12 hours.

For this reason, comfort isn’t a luxury; it’s a safety feature. An astronaut who is distracted by an uncomfortable suit is not fully focused on the mission. The Starliner suit’s ventilation system is essential for managing heat and humidity inside the suit, keeping the astronaut cool and dry. The lighter weight of the suit also reduces fatigue, especially from the force of gravity pulling on them while they wait on the launch pad. The suit must also be designed to accommodate basic biological needs, which typically involves a Maximum Absorbency Garment (MAG) worn underneath.

Comparative Analysis: Starliner Suit vs. Contemporaries

The Starliner suit did not emerge in a vacuum. It is one of several new-generation IVA suits, each reflecting the specific mission and design philosophy of its parent company.

SpaceX IVA Suit

The most direct comparison to the Starliner suit is the one developed by SpaceX for its Crew Dragon vehicle. The SpaceX suit is famous for its sleek, futuristic, black-and-white aesthetic. While the “Boeing Blue” suit looks like a functional evolution of past designs, the SpaceX suit looks like something from a science fiction film.

Despite the visual differences, the core function is identical. It is a lightweight, launch-and-entry IVA suit designed to protect against depressurization.

• Design: The SpaceX suit was designed in-house, with input from Hollywood costume designer Jose Fernandez. Its aesthetic is a key part of the SpaceX brand.
• Helmet: The SpaceX helmet is a single-piece, 3D-printed, hard-shell design, very different from Starliner’s soft hood.
• Function: Like Starliner, it has a single umbilical connection to the seat, provides cooling and breathing air, and features touch-screen-compatible gloves.
• Fit: It appears to be more custom-fitted to each astronaut, potentially offering less modularity than the Starliner design.

Both suits solve the same problem, but their designs showcase different corporate philosophies: Boeing’sreliance on an established aerospace partner (David Clark Company) versus SpaceX’s vertical integration and in-house design.

NASA’s Orion Crew Survival System (OCSS)

This is the suit NASA astronauts will wear on Artemis program missions to the Moon, flying in the Orioncapsule. The OCSS is a heavily modified version of the shuttle’s orange ACES suit.

The OCSS is a much heavier-duty suit than Starliner’s, and for a good reason. A Starliner mission to the ISSlasts hours or a day. An Artemis mission to the Moon takes weeks. If the Orion capsule were to depressurize halfway to the Moon, the crew couldn’t be home in a few hours.

The OCSS is designed to keep an astronaut alive for up to six days in a depressurized capsule. It’s a “lifeboat” built for a much longer and more perilous journey. It has a more robust thermal protection, a more advanced waste management system, and is generally a bulkier, more complex suit. It shows that the mission defines the suit. The Starliner suit is a “commuter” suit for low Earth orbit, while the OCSS is a “trans-oceanic” suit for deep space.

Legacy Suits: ACES and Sokol

The Starliner suit stands on the shoulders of two giants: the American ACES and the Russian Sokol.

• ACES (Advanced Crew Escape Suit): The “pumpkin suit” is the direct ancestor of the OCSS and the spiritual predecessor to Starliner, as it was also made by the David Clark Company. The Starliner suit learned all the lessons of ACES and improved on them, specifically in weight, mobility, and comfort.
• Sokol Suit: The Russian IVA suit used for Soyuz flights is a model of rugged reliability. It’s been used for decades. Conceptually, it is very similar to the Starliner suit: a soft suit with an integrated soft hood that inflates in an emergency. The Starliner suit can be seen as the 21st-century American equivalent of the time-tested Sokol, integrating modern materials, touch-screen gloves, and advanced manufacturing.

Testing, Certification, and Flight Readiness

A new spacesuit doesn’t go from the design studio to the launch pad. It must first go through years of grueling tests to prove it can keep an astronaut alive. NASA has a rigorous certification process for all Commercial Crew Program hardware, and the suit is no exception.

Vacuum Chamber Tests

The most important test is proving the suit works in a vacuum. Test dummies, and later human test subjects, wear the suit inside a large vacuum chamber. The air is then pumped out of the chamber to simulate a total loss of cabin pressure.

Engineers and NASA officials watch to ensure the suit inflates correctly, maintains the proper pressure, and doesn’t leak. The test subjects will perform tasks, like reaching for controls, to see how mobile they are when the suit is fully pressurized. This is a pass/fail test: the suit must perform, or it’s back to the drawing board.

Mobility and Egress Testing

Astronauts practice wearing the suit in high-fidelity mockups of the CST-100 Starliner capsule. They practice climbing into their seats, strapping in, and reaching every single button, switch, and screen.

More importantly, they practice emergency egress. This involves drills where they must unstrap and exit the capsule as quickly as possible, simulating a fire or other emergency on the launch pad. They also perform tests in water to ensure that if the capsule splashes down in the ocean, an astronaut in the suit can safely exit and wait for recovery.

Astronaut Feedback and Iteration

The most valuable test data comes from the astronauts themselves. The NASA crews assigned to fly Starliner, such as Barry E. Wilmore and Sunita Williams, spent years working with the suit.

Their feedback is specific and practical. An astronaut might report that a seam chafes after six hours, that a particular helmet angle creates a glare on a control screen, or that a glove is too stiff to flip a specific switch. This feedback is sent directly to Boeing and the David Clark Company, who then iterate on the design. This continuous refinement loop, driven by the end-users, is what ensures the suit is not just safe, but also effective.

The Starliner Suit in Practice: The Crew Flight Test

The suit’s final exam was the Boeing Crew Flight Test (CFT), which launched in June 2024. Astronauts Butch Wilmore and Suni Williams became the first people to fly to space wearing the “Boeing Blue” suits.

They wore the suits during the ascent, the docking with the International Space Station, and later for the undocking and re-entry. This was the first time the suit was operated in a true microgravity environment during a mission.

During the mission, the suits performed their intended function: they were worn for the dynamic phases and then stowed, with the astronauts changing into regular clothes to work on the station. While the Starliner vehicle experienced challenges during the mission that extended the crew’s stay, the suits themselves performed as designed. The data collected from this first flight – on comfort, usability, and integration with the spacecraft – was invaluable, providing the final validation that the suit was ready for operational missions.

The Future of IVA Suit Technology

The Starliner suit is a product of its time, incorporating modern materials and design principles. But technology does not stand still. Future IVA suits will likely be even more advanced.

We can expect to see even lighter materials and more innovative joint designs that allow for full mobility, even when the suit is pressurized. This is the “holy grail” of suit design.

Another area of development is “smart” suits. Future suits may have biometric sensors woven directly into the fabric, monitoring the astronaut’s heart rate, breathing, and temperature, and feeding that data directly to mission control. Integrated, heads-up displays inside the helmet, projecting key data onto the visor, could also become standard.

As humanity looks toward longer and more complex missions, such as trips to Mars, the lines between suit types may blur. Astronauts on a Mars mission might need a single, “hybrid” suit that can serve as a lightweight IVA suit during transit but also function as a full-fledged EVA suit for exploring the Martian surface.

Summary

The Boeing Starliner IVA suit is far more than a simple flight suit. It is a key component of the CST-100 Starliner spacecraft, a personal life support system designed as the last line of defense for the crew. Developed by the David Clark Company for Boeing’s participation in NASA’s Commercial Crew Program, its “Boeing Blue” design is a purpose-built solution for crewed flight in low Earth orbit.

It is lighter, more flexible, and more comfortable than its shuttle-era predecessors. Its design, from the soft-hood helmet to the touch-screen-compatible gloves, is integrated with the Starliner’s modern cockpit. While its primary function is to protect the crew from depressurization or a toxic atmosphere, its design is centered on the human factor, ensuring astronauts can comfortably and effectively pilot their vehicle. Having been proven in flight, the Starliner suit now stands as a mature and critical piece of technology enabling the next generation of human spaceflight.