What is the Artemis Orion Crew Survival System?

A New Generation of Personal Protection

Human spaceflight is an inherently risky endeavor. Traveling beyond Earth’s atmosphere means leaving behind the systems that naturally provide breathable air, stable pressure, and protection from extreme temperatures. While spacecraft are designed to provide this environment, history has shown that contingencies must be prepared for. This is the domain of the Orion Crew Survival System, or OCSS. It is a specialized, integrated system designed to protect astronauts during the most dynamic and hazardous phases of a mission aboard NASA’s Orion spacecraft.

The OCSS is much more than just a spacesuit. It is a personalized life support system, a survival garment, and a key piece of vehicle equipment. Its primary function is to act as a self-contained environment that can keep an astronaut alive, safe, and functional in the event of a cabin depressurization, a fire, or any other life-threatening emergency. Astronauts participating in the Artemis program wear the OCSS during launch, ascent, re-entry, and landing. They also have the capability to wear it during high-risk maneuvers or if a problem arises in deep space.

It is important to differentiate the OCSS from its more famous counterpart, the spacewalking suit. The OCSS is an Intra-Vehicular Activity (IVA) suit. It is not designed for astronauts to perform work outside the spacecraft in the vacuum of space. That task falls to the Exploration Extravehicular Mobility Unit (xEMU), a far more complex and bulky suit that functions as a miniature spacecraft. The OCSS, by contrast, is optimized for mobility inside the capsule, protection, and emergency survival. It is the astronaut’s last line of defense, a personal lifeboat designed to function when all other systems have failed.

Historical Context and Evolution

The OCSS is the product of decades of experience and hard-won lessons from previous space programs. Every generation of American spacecraft has had its own specialized pressure suit, and each design reflects the technology and the specific risks of its era.

The earliest suits of the Project Mercury program were modified high-altitude pressure suits from experimental test pilot programs. They were simple, silver-colored garments designed to protect the solo astronaut if the small capsule lost pressure. The Project Gemini suits evolved from this, becoming more flexible to allow astronauts to move around the two-person capsule and even conduct the first American spacewalks, though these early EVAs proved incredibly difficult.

The Apollo program required a “do-everything” suit, the A7L. This one suit had to serve as an IVA suit for launch and re-entry, and, with the addition of an outer thermal-micrometeoroid garment, it became the iconic EVA suit worn on the Moon. It was a marvel of engineering, but it was also complex and tailored to the specific needs of landing on another world.

With the Space Shuttle program, the approach changed again. In the earliest flights, astronauts wore brown-colored ejection suits, as the shuttle had ejection seats. After the Challenger accident in 1986, NASA introduced the Launch Entry Suit (LES), a partially pressurized garment. This was later replaced by the familiar “pumpkin suit,” the Advanced Crew Escape Suit (ACES). The ACES was a fully pressurized, high-visibility orange suit with its own survival gear, and it served as the direct ancestor to the OCSS.

The OCSS builds directly on the proven foundation of the ACES. It takes the core design and philosophy – a lightweight, full-pressure suit focused on survival – and updates it with new materials, technologies, and capabilities specifically for the challenges of deep-space missions. The Orion spacecraft will fly farther from Earth than any human-rated vehicle before it, meaning a return trip in an emergency could take days, not hours. This single fact dictated a massive leap in capability from the ACES to the OCSS.

The OCSS Suit: A Detailed Look

The most visible component of the OCSS is the suit itself, formally known as the Pressure Garment Assembly (PGA). This is the astronaut’s personal pressure vessel, designed with multiple layers to be as mobile and comfortable as a life-preserving suit can be.

The Pressure Garment Assembly (PGA)

The PGA is what most people picture when they think of the OCSS. Its most striking feature is its color: International Orange. This specific shade was chosen for the same reason it was used on the ACES – it provides the highest possible visibility for search-and-rescue teams, particularly against the dark blue backdrop of the ocean, where Orion is designed to land.

The suit is constructed in layers. The outermost layer is made of a material called Nomex, a flame-resistant fiber that protects the astronaut from fire. This layer is tough and durable, built to withstand the rigors of launch and landing. Beneath this outer shell is the “bladder” or pressure-retention layer. This layer is typically made of urethane-coated nylon and is the part of the suit that actually holds the air, maintaining a livable pressure around the astronaut’s body. Closest to the skin is a comfort liner, which helps with ventilation and prevents chafing.

One of the most significant advancements over the ACES is in mobility. A suit filled with air becomes rigid, like a stiff balloon, making it difficult to move. The OCSS features improved joint designs at the shoulders, elbows, hips, and knees. These joints use special bearings and gussets that allow for a much greater range of motion, letting astronauts reach controls, move in their seats, and perform emergency tasks even when the suit is fully pressurized. This is essential for a vehicle like Orion, where crews may need to be functional for long periods in a pressurized suit.

Helmet and Communications

The OCSS helmet is a marvel of simplicity and strength. Unlike the multi-part helmets of the Apollo era, the OCSS helmet is a large, clear, single-piece polycarbonate dome. This design provides an exceptionally wide and unobstructed field of view, which is important for situational awareness inside the capsule. The helmet is attached to the suit via a “neck ring,” which features a bearing that allows the astronaut to turn their head left and right, another key mobility feature.

The helmet incorporates a system to prevent the visor from fogging up. A flow of air is directed across the inside of the visor to clear away humidity. It also features a “contingency feed port,” a small valve where, in an emergency, an astronaut could receive drinking water without removing the helmet. A sunshade can be pulled down over the clear visor to protect the astronaut’s eyes from bright sunlight, especially during a re-entry where the capsule’s orientation might expose them to the sun’s full glare.

Communications are handled by a fabric “comm cap,” worn under the helmet. This cap, which looks like a snug skullcap, contains integrated earpieces and microphones. A cable from the cap connects to the suit’s interior, which then patches into the spacecraft’s communication system through the umbilical. This setup provides clear, hands-free audio for the crew to talk with each other and with Mission Control. The OCSS helmet also features new upgrades like integrated, high-intensity lights and a high-definition camera, allowing ground crews to see exactly what an astronaut is looking at.

Gloves and Boots

The hands and feet are two of the most complex parts of the body to protect. OCSS gloves must be strong enough to hold pressure but flexible enough to allow astronauts to flip switches, type on keyboards, and interact with touch screens. The OCSS gloves are a major improvement over previous designs. They are more flexible and have been specifically designed with material on the fingertips that allows for the operation of the Orion spacecraft‘s advanced touch-screen displays. The palms are designed for a secure grip, letting astronauts hold on during high-G maneuvers or climb out of the capsule after splashdown.

The boots are similarly specialized. They are lightweight and, like the rest of the suit, fire-resistant. The soles are designed to interface perfectly with the foot restraints on the Orion’s seats, locking the astronaut in place for the dynamic launch and landing phases. The tread pattern is designed to provide traction on a variety of surfaces, an important consideration if the crew has to make an emergency exit on land or walk on the deck of a recovery ship.

Life Support and Thermal Control

Staying alive inside a sealed suit requires more than just oxygen. The human body generates a tremendous amount of heat, and in a sealed environment, that heat can become deadly. To manage this, astronauts wear a Liquid Cooling and Ventilation Garment (LCVG) as their first layer, under the pressure suit.

The LCVG is a full-body garment, similar to long underwear, that has a network of thin tubes stitched into its fabric. Cool water is pumped from the spacecraft, through the umbilical, and into these tubes. The water circulates over the astronaut’s body, picks up excess heat, and then flows back out to the spacecraft’s life support system to be re-chilled. This same garment also includes ventilation tubes that pull the warm, humid air from inside the suit (from the astronaut’s breathing and sweat) and send it back to the vehicle’s system to be scrubbed of carbon dioxide and humidity.

In an emergency where the astronaut must disconnect from the vehicle’s umbilical – such as a bailout or post-landing survival scenario – the suit has its own emergency oxygen supply. This “bailout bottle” provides a limited amount of breathable air. For managing bodily waste during long-duration suit operations, astronauts wear a Maximum Absorbency Garment, a highly absorbent brief.

Safety and Survival Gear

The OCSS is a complete survival system. Integrated directly into the suit’s layers and pockets is a comprehensive kit of survival gear. For a splashdown, the suit has an integrated personal flotation device (PFD) that automatically inflates. It also includes a “personal locator beacon” that sends a signal to rescue forces.

Packed into pockets are a variety of other tools: a signal mirror, a strobe light, a whistle, sea dye markers (to make the water around the astronaut more visible from the air), and flares. A small medical kit and a utility knife are also included. This gear ensures that if an astronaut must egress the capsule in a remote location, they have the tools to survive and signal for help until recovery teams can reach them.

The Vehicle Interface: Beyond the Suit

The “System” part of OCSS is what truly separates it from its predecessors. The suit is only one half of the equation; the other half is its deep integration with the Orion spacecraft itself. The suit and the vehicle were designed in parallel, ensuring they work together seamlessly.

The primary connection point is the “umbilical,” a set of hoses and cables that plug directly from the astronaut’s seat into the suit. This umbilical is the suit’s lifeline to the spacecraft. Through these connections, the astronaut receives:

• Breathable Air: A regulated mix of oxygen and nitrogen.
• Cooling Water: The continuous flow for the LCVG.
• Suit Ventilation: The system that pulls CO2 and humidity out of the suit.
• Power: Electricity to run the suit’s internal systems, like helmet lights.
• Communications: The hard-line connection for the comm cap.
• Data: Information from the suit’s sensors fed back to the spacecraft.

This connection allows the suit to leverage the full power and resources of the spacecraft’s life support system. However, the system is also designed for rapid disconnection. In an emergency egress, an astronaut can quickly unhook this umbilical and switch to the suit’s self-contained life support functions.

The Orion seat system is the other key piece of the interface. Each seat is custom-molded for its occupant. The suit is designed to fit into this seat perfectly, with recesses and connection points for the umbilical and restraint systems. The entire seat-and-suit system is designed to absorb the immense G-forces of a launch, a re-entry, and, most importantly, a high-altitude abort using the Launch Abort System. This system would pull the capsule away from a failing rocket, subjecting the crew to intense acceleration. The OCSS and seat work together to ensure the crew can survive these forces.

OCSS Operations and Scenarios

The OCSS is designed for specific, high-stakes portions of a mission. Its operational use can be broken down into normal flight phases and emergency contingencies.

Launch and Ascent

On launch day, the Artemis crew dons their OCSS suits with the help of suit technicians. They then board the Orion spacecraft and plug their suits into the vehicle’s systems. During the entire launch and ascent sequence, the astronauts are fully suited.

In this phase, the suit’s primary function is preventative. It is ready to protect the crew instantly from a fire, a toxic atmosphere from a propellant leak, or a sudden depressurization of the cabin. The suit is typically worn in an “unpressurized” state, meaning it’s not inflated. This allows the astronauts to be more comfortable and mobile. If cabin pressure were to drop, the suit would automatically inflate to protect them.

Re-entry and Landing

After the mission is complete, whether it’s a trip around the Moon or a longer expedition, the crew once again dons their OCSS suits for the return to Earth. The re-entry phase, while typically very accurate, is another high-risk part of the flight. The capsule endures extreme temperatures as it blazes through the atmosphere. The OCSS provides protection from a cabin breach and the heavy G-loads of deceleration.

Once the parachutes deploy and the capsule splashes down in the ocean, the suit’s role shifts to post-landing survival. The crew may remain in their suits for hours while they await recovery. The suit keeps them warm, and if they must exit the capsule into the water, its flotation devices and survival gear are immediately available.

Contingency Scenarios: When Things Go Wrong

The true purpose of the OCSS is revealed in how it handles emergencies. Its design is driven by a series of “what if” scenarios.

Scenario 1: Cabin Depressurization

This is the most straightforward contingency. If a micrometeoroid or piece of debris punctures the Orion’s hull, the cabin air will rush out into space. The OCSS sensors would detect this pressure drop and automatically inflate the suit’s bladder, creating a pressurized, oxygen-rich environment around the astronaut.

What makes this scenario unique for Artemis is the duration. Unlike the Space Shuttle, which could return to Earth in hours, a depressurization on the way back from the Moon could leave the crew days from home. The OCSS is designed to keep the crew alive in their pressurized suits, plugged into the vehicle’s remaining resources, for up to six days. This incredible requirement means the suit must be a comfortable and functional home, not just a temporary shield.

Scenario 2: Cabin Fire or Toxic Atmosphere

A fire inside a spacecraft is one of the most feared emergencies. It not only poses a thermal threat but also fills the cabin with toxic smoke. In this event, astronauts would seal their helmets, and the OCSS would provide them with a self-contained supply of breathable air, completely isolated from the contaminated cabin environment. This gives the crew time to fight the fire or initiate an abort.

Scenario 3: Launch Abort

If the Space Launch System (SLS) rocket were to fail on the launch pad or during ascent, the Launch Abort System would ignite, violently pulling the Orion capsule away from the rocket. The OCSS, in conjunction with the energy-absorbing seats, is designed to protect the crew from the intense G-forces and any subsequent hard landing or splashdown.

Design, Manufacturing, and Testing

The OCSS is not built by NASA directly, but by a specialized contractor: the David Clark Company. This company has a long and storied history in aerospace, having built pressure suits for test pilots and astronauts stretching back to the Gemini program and the ACES suit for the Space Shuttle.

The design philosophy was to start with the proven, flight-tested ACES design and modify it for the specific demands of deep space. This meant retaining the core concepts of a lightweight, full-pressure suit but enhancing almost every aspect of it.

Key upgrades from ACES include:

• Enhanced Mobility: New joints in the shoulders, elbows, and hips make it much easier to move.
• Reduced Mass: New materials make the suit lighter, reducing fatigue.
• Fire Resistance: The OCSS is fire-resistant from the inside out, a lesson from previous incidents.
• Improved Helmet: The single-piece dome offers a better field of view and is lighter and stronger. It’s also quieter, reducing the noise of airflow inside.
• Advanced Gloves: The ability to operate touch screens is a new requirement for Orion’s glass-cockpit design.
• Extended Survival: The entire system is built to support a crew for up to 144 hours (six days).

This table highlights some of the key differences between the legacy ACES suit and the new OCSS.

A Rigorous Testing Regimen

Before any human flies with new hardware, that hardware must be subjected to a punishing series of tests. The OCSS has undergone one of the most thorough testing campaigns in NASA’s history.

Engineers used vacuum chambers to simulate a rapid cabin depressurization, ensuring the suit would inflate correctly and protect its occupant. Suits were exposed to extreme heat and cold to verify their thermal performance. Mobility tests were conducted, with engineers and astronauts wearing the suit inside a full-scale mockup of the Orion spacecraft, practicing reaching every control and moving in and out of their seats while the suit was pressurized.

A major focus was on splashdown and egress testing. Test dummies and later human volunteers in OCSS suits were dropped into NASA’s Neutral Buoyancy Laboratory (NBL), a massive indoor pool, to test the suit’s flotation devices and to practice emergency exit procedures. These tests were then moved to the open ocean, where crews practiced exiting the capsule in real-world waves, coordinating with U.S. Navy recovery teams.

The most high-fidelity test came with the Artemis I mission. While no crew was aboard, the commander’s seat was occupied by “Commander Moonikin Campos,” a sophisticated test dummy clad in a fully flight-configured OCSS. This “Moonikin” was outfitted with sensors to measure the radiation, vibration, and G-forces that a human crew member would experience during the entire mission, from launch to splashdown. This data was invaluable in validating that the suit and seat system performed as designed.

The Human Element: Training and Integration

The OCSS is a complex piece of equipment, and using it is a skill that must be learned and practiced extensively.

The process begins with fitting. Each suit is custom-tailored to its astronaut. NASA uses 3D body-scanning technology to create a precise digital model of each astronaut. From this model, the David Clark Company manufactures a suit that fits perfectly. A poor fit can create pressure points when the suit is inflated or restrict an astronaut’s mobility.

Once they have their suit, astronauts begin rigorous training. They practice “donning and doffing” (putting on and taking off) the suit, a procedure that requires assistance from suit technicians and follows a specific checklist. They spend hours in mockups, learning to operate the Orion spacecraft‘s controls while wearing the bulky gloves.

A large part of the training involves working in a fully pressurized suit. Astronauts describe this as trying to work while being “squeezed by a stiff balloon.” Every movement is difficult and requires exertion, as they must fight against the suit’s internal pressure. They practice these pressurized drills repeatedly to build muscle memory, ensuring they can perform emergency tasks even under such difficult conditions.

Finally, they run through countless emergency simulations. In the Orion mockup, trainers will call out a simulated fire or depressurization, and the crew must execute their emergency procedures perfectly. This training culminates in the ocean egress training, where the Artemis II crew – the first humans who will fly in Orion – practiced their survival skills in the water, just as they would after their lunar mission.

Summary

The Orion Crew Survival System is far more than just a new spacesuit. It is a comprehensive, fully integrated survival system that pairs a state-of-the-art pressure garment with the deep-space capabilities of the Orion spacecraft. It represents the evolution of a design lineage that stretches back to the Space Shuttle program, upgraded and re-engineered for the unique challenges of the Artemis program.

From its flame-retardant orange shell and touch-screen-compatible gloves to its six-day emergency life support capability, every component of the OCSS is designed with one purpose: to ensure the safety of the crew during the most hazardous phases of their journey. As NASA and its partners return humans to the Moon and look onward to Mars, the OCSS serves as a personal, pressurized lifeboat, providing a last line of defense against the unforgiving environment of space.