Unlike the International Space Station (ISS), which recycles nearly 90% of water from urine and sweat into drinking water, the Orion capsule has no waste recycling system.
Orion is designed for short lunar missions. It simply stores liquid waste and vents it overboard several times a day. Solid waste is compacted in odor-controlled canisters for return to Earth.
Think of the ISS as a permanent home with a closed-loop water cycle, and Orion as a campervan on a weekend trip—efficient for its short duration, but far from a recycling marvel.
From ISS to Orion: Discover how NASA’s next-gen waste recycling system redefines astronaut living, enabling safe and sustainable deep space missions.
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| Recycling systems in space missions |
How Does the Orion Capsule’s Waste Recycling System Differ from the International Space Station (ISS)?
Ever wonder how astronauts "go" in space? It's a lot more complicated than you might think. Both the International Space Station (ISS) and the new Orion capsule are equipped with advanced toilets, but they operate on completely different principles.
Think of it like the difference between a permanent, off-grid homestead and a cross-country road trip in a campervan.
The ISS is a permanent home, designed for crews to live and work for months at a time, requiring a sophisticated closed-loop system that recycles almost everything.
Orion, on the other hand, is a short-term vehicle, taking astronauts on intense, multi-day journeys to the Moon.
This fundamental difference in mission design dictates everything about how waste is handled.
On the International Space Station, "today's coffee" is tomorrow's coffee, but on Orion, what goes in doesn't always come back around.
Let's dive into the fascinating, and sometimes surprising, engineering behind these two very different approaches.
The Closed-Loop Marvel of the ISS
The International Space Station operates as a near-perfect closed loop, where almost nothing is wasted. Its Environmental Control and Life Support System (ECLSS) captures and recycles nearly all forms of water-based liquids, including urine, sweat, and even moisture from the crew’s breath.
This is a cornerstone of its ability to support long-duration missions with minimal resupply from Earth.
The system is a marvel of chemical and mechanical engineering, designed to function reliably for months or even years in microgravity without hands-on maintenance.
The ISS turns yesterday's waste into today's drinking water, and mimics elements of Earth's natural water cycle, drastically reducing the cost and complexity of launching countless gallons of water from Earth.
Orion's Straightforward "Store and Vent" Approach
In stark contrast, the Orion capsule for the Artemis missions utilizes a much simpler approach better suited for its short 10-day flights.
While it shares the Universal Waste Management System (UWMS) hardware with the ISS, it lacks the heavy water-recycling equipment.
On Orion, liquid waste is collected and then, several times a day, vented directly into the vacuum of space.
Solid waste is collected in odor-controlled canisters that the crew manually compresses, which are then brought back to Earth for disposal.
This “store and vent” method is far less complex than the ISS’s system, saving significant mass and volume inside the cramped Orion capsule.
The Universal Waste Management System (UWMS)
The key piece of hardware common to both vehicles is the UWMS, a $23 million, next-generation space toilet. It's designed to be universal, easily integrated into different spacecraft.
In microgravity, the UWMS uses powerful airflow to suck urine and feces away from the astronaut's body, preventing floating waste.
Astronauts use a funnel and hose for urination and a seat with a hole for bowel movements.
By popular demand, the UWMS is 65% smaller and 40% lighter than the old ISS toilet, and includes more ergonomic features and an automatic fan that starts when the lid is opened, improving both comfort and odor control.
The ISS: From Urine to Drinkable Water
On the ISS, the UWMS is integrated into a complex recycling chain. Its primary role is to pre-treat urine so it can be safely processed by the station's Water Recovery System.
The Urine Processor Assembly (UPA) recovers about 75% of the water from urine by heating and vacuum distillation. This recovered water, now separated from the brine, is sent to the Water Processor Assembly (WPA) for further purification.
The WPA uses a multi-stage process of filtration and chemical treatment to produce clean, potable water that exceeds many Earth-based drinking water standards.
This sophisticated system, which recycles about 90% of all water-based liquids, is the lifeblood of the station.
The Orion: No Water Recycling at All
Because the Orion missions are so short, the UWMS operates as a standalone unit without any downstream recycling components.
The urine hose leads to a small holding tank, which is only about the size of an office trash can. Once this tank fills up, the crew performs a "dump," where the pre-treated urine is vented overboard, creating a spectacular show of gleaming particles streaming past the window.
This approach saves the mass, volume, and power that a full recycling system would require, which are critical resources on a deep-space vehicle where every kilogram is carefully managed.
The Odyssey of Odor Management
A fascinating engineering challenge for both vehicles is odor control. To prevent the small cabin from smelling like an outhouse, NASA has developed advanced filtration systems.
For Orion, a compact, multilayer sorbent bed is integrated directly into the toilet. This filter uses specialized materials to capture a myriad of smelly gases—like ammonia, hydrogen sulfide, and mercaptans—before they enter the crew’s living environment.
These disposable filters are swapped out during the mission, ensuring the air remains fresh.
The ISS, with its larger volume, uses a similar but more permanent odor-scrubbing system within its air revitalization loop to keep the station habitable.
From Apollo Bags to High-Tech Thrones
To appreciate the UWMS, it's worth looking at the "bad old days" of Apollo. Early astronauts had no toilets; they were forced to use crude plastic bags for solid waste, which they would stick to their bottoms, and a simple relief tube for urine.
The process was notoriously messy and uncomfortable, once memorably described in mission transcripts as “a turd through the air”.
The UWMS, with its private compartment, ergonomic restraints, and air-flow system, represents a giant leap in dignity for space travelers. It’s a high-tech throne designed for the harsh realities of microgravity, proving that even the most basic human needs require sophisticated solutions in space.
The "Space Plumber" and Hardware Glitches
Even with advanced engineering, space toilets can be finicky. On the Artemis II mission, the UWMS suffered a fan jam in the urine collection system hours after launch. This forced the crew to rely on collapsible contingency urinals, which are essentially modern versions of the Apollo bags.
Mission specialist Christina Koch famously became the crew's "space plumber," diagnosing the problem (a pump that wasn't primed with enough water) and getting the toilet back online with help from Mission Control.
Later in the mission, an ice buildup blocked the vent nozzle during a urine dump, temporarily grounding the "go" for urination. These hiccups are valuable lessons for future deep-space hardware.
The Future: Towards 98% Recycling for Mars
While the ISS system is impressive, it’s not the final word. NASA’s goal is to reach a 98% water recycling rate before launching the first human missions to Mars, which could take about two years round trip.
To achieve this, future systems will need to recover water not just from urine, but also from feces, which is currently not processed on either vehicle.
The space station is the perfect testing ground for these advanced technologies.
The goal is a fully closed-loop system that mimics Earth’s ecology, where every molecule of water is recycled indefinitely, ensuring that future astronauts can travel farther than ever before.
Read Here: How Do Astronauts Sleep and Eat in Deep Space?
Conclusion
The Orion capsule’s waste recycling system represents a leap forward in sustainable space travel compared to the ISS.
While the ISS relies on established methods of waste collection and partial recycling, Orion integrates advanced closed-loop technologies designed for deep space missions. This system minimizes resource loss, reduces dependency on Earth resupply, and ensures astronauts can safely manage waste during long-duration journeys beyond low Earth orbit.
By converting waste into usable byproducts and optimizing storage, Orion not only improves efficiency but also enhances crew health and mission reliability.
These innovations highlight NASA’s commitment to developing spacecraft that support human exploration of the Moon, Mars, and beyond.
In essence, Orion’s waste recycling system is more than a technical upgrade—it is a vital step toward self-sufficient living in space, redefining how humanity prepares for its next giant leap into the cosmos.
Read Here: Timeline for NASA Artemis Mission to the Moon
References
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- Nairobi News. (2026, April 6). NASA's Artemis space toilet proves vital on Lunar Flyby. http://nairobinews.co.ke/nasas-artemis-space-toilet-proves-vital-on-lunar-flyby/
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- New York Post. (2016, November 18). This new process to recycle pee is the key to deep space travel. https://nypost.com/2016/11/18/this-new-process-to-recycle-pee-is-the-key-to-deep-space-travel/
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