Surviving Deep Space: A Look at the Orion Spacecraft

In 2022, the Artemis I mission tested the deep space capabilities of NASA's Orion spacecraft for the first time as it orbited the Moon and returned safely back to Earth, laying the groundwork for future crewed missions to the Moon and beyond. With the launch of Artemis II on April 1, 2026, Orion once again traveled past the skies to the Moon, only this time with four humans on board.

The Artemis II mission's 10-day excursion serves as a critical stepping-stone toward lunar surface landing, where the spacecraft's critical functions will be tested for future deep-space missions. The most important being the systems that keep the crew alive and comfortable inside the spacecraft, known as the Environmental Control and Life Support System (ECLSS).

"The Environmental Control and Life Support System is logically the first core function of Orion," said Sean O'Dell, Orion Spacecraft Architect at Lockheed Martin. "Designing the spacecraft right is starting from the people onboard and working outward."

What is Environmental Control and Life Support System?

ECLSS is designed to provide a habitable, healthy environment for the four crew members in both short-sleeve and suited operations under a variety of conditions, from pre-launch to landing and recovery. It must maintain a breathable atmosphere including removing carbon dioxide and other harmful contaminants, while sustaining a comfortable cabin temperature.

To achieve this, ECLSS integrates multiple subsystems that collectively create and maintain a habitable environment inside the crew module, or living quarters.

The Subsystems that Make Orion Habitable

Air Revitalization System

Inside the spacecraft's sealed cabin, air must be constantly monitored and conditioned. The Air Revitalization System on Orion maintains appropriate oxygen levels while removing carbon dioxide and trace contaminants generated by crew and onboard equipment.

Oxygen and nitrogen are supplied from storage tanks, while carbon dioxide is captured using a regenerative chemical scrubbing technology called amine swing beds. Continuous circulation and atmospheric monitoring ensure a stable, breathable environment throughout the mission.

In a closed spacecraft cabin, water vapor accumulates quickly from crew respiration, sweat during exercise and other sources. Orion's humidity control system captures excess humidity, converts it to liquid water and stores it as wastewater for disposing.

This system can maintain a positive pressure, breathable atmosphere, and thermal cooling for up to 144 hours to the four suited crew members in the event of a pressure vessel leak or contaminated cabin atmosphere.

Active Thermal Control System

Space presents extreme temperature conditions, with spacecraft surfaces exposed to intense solar radiation on one side and frigid darkness on the other. Orion's Active Thermal Control System protects both astronauts and onboard electronics by maintaining a stable internal temperature.

The system circulates coolant fluids through heat exchangers to absorb excess heat and transfers it to external radiators, where it is rejected into space. It works similar to a car's radiator, using coolant to actively regulate temperatures, prevent overheating and shield sensitive systems from the damaging heat.

During its mission, Orion's crew cabin will stay a comfortable room temperature of around 70-75°F, even during reentry through the Earth's atmosphere.

Potable Water System

The water supply on Orion provides drinking water for food preparation, medical needs and hygiene activities during the mission.

The system relies on pressurized storage, controlled plumbing lines, and filtration to ensure water quality and reliable distribution. Orion can carry about 74 gallons of water in its four tanks.

Waste Management System

Orion's Universal Waste Management System (WMS), or toilet, is nearly identical to what astronauts already use on the ISS and is built for use in exploration missions. However, Orion's WMS is improved for reduced size and mass due to the constraints of a deep space vehicle. Orion has a dedicated hygiene bay, or bathroom, for privacy while using the WMS.

The WMS is engineered to collect and contain both liquid and solid waste hygienically within the spacecraft's confined environment. Airflow-assisted collection, provided by dual fan separators, directs waste into sealed containers, while filtration components help control particulates and odors.

Effective waste management is essential to maintaining cabin cleanliness and crew health during extended missions.

Fire Detection and Suppression System

Fire represents one of the most serious risks in a closed spacecraft environment. Orion's Fire Detection and Suppression System actively monitors the cabin atmosphere for smoke and combustion byproducts.

If a potential fire is detected, much like an at home smoke detector, onboard sensors trigger alarms, allowing astronauts to respond quickly using specialized suppression equipment designed for microgravity conditions.

Continuous monitoring and rapid response capability are critical safeguards during deep-space missions.

Together, these subsystems form Orion's ECLSS, an engineered ecosystem that transforms a spacecraft into a livable habitat.

Testing Orion's ECLSS

Orion Life Support Integration Facility

The OLIF, a purpose-built lab at NASA's Johnson Space Center developed jointly by Lockheed Martin and NASA, served as the hardware testbed for ECLSS.

Engineers ran "physics-only" tests to verify core engineering principles before software integration, including pressure-control checks that kept cabin oxygen, nitrogen, and carbon dioxide within limits, even during fault conditions.

A humidity-feedback loop was evaluated to maintain safe moisture levels in crew-suit ventilation, preventing condensation. Finally, vacuum-chamber tests simulated near-space conditions, confirming that swing-bed seals remained leak-tight during repeated cycling.

Integrated Test Lab

The ITL near Denver complements the OLIF by validating the software that commands and monitors the hardware functions. Engineers verify closed-loop control across simulated mission phases, adjusting oxygen levels, CO₂ filtration, and coolant flow automatically. They also conduct full-mission end-to-end simulations, injecting sensor noise, timing glitches and fault conditions (e.g., a stuck valve) to test diagnostics and resolution capabilities.

Together, the OLIF and the ITL provided comprehensive testing that Orion's ECLSS not only works on paper but also operates reliably as an integrated system.

"We've leveraged NASA's decades of human spaceflight experience to develop ECLSS", said O'Dell. "ECLSS does far more than keep astronauts alive, it creates a stable, safe, and livable environment in one of the harshest settings imaginable, deep space."

As Artemis missions push humans farther from Earth than ever before, ECLSS will quietly perform the essential work of sustaining the crew day after day, enabling astronauts to focus on exploration, discovery, and ultimately paving the way for a sustained human presence beyond low-Earth orbit.