The only door on the ship — and it's on the toilet.
Four astronauts are about to spend ten days inside a capsule roughly the size of a large camping tent, traveling 400,000 kilometers from Earth. Before they get there, someone has to answer the unglamorous question that every curious person eventually asks: what do you do when you need to use the bathroom?
Canadian Space Agency astronaut Jeremy Hansen recently walked through the answer in a tour of the toilet trainer — the ground-based replica used to prepare the Artemis II crew for one of the more intimate realities of deep space travel. His explanation is a useful reminder that the engineering behind a Moon mission extends well beyond rockets and navigation computers.
The contrast with the Apollo era is stark. In the 1960s, astronauts had no dedicated toilet at all. Solid waste went into plastic bags. Urine was managed through a rudimentary tube. The whole arrangement was, by most accounts, miserable — messy, odorous, and a source of genuine discomfort on missions that already demanded everything from the people making them. Decades of iteration have produced something considerably more dignified.
The system now installed in the Orion spacecraft is called the Universal Waste Management System, the same technology developed for the International Space Station. Because there is no gravity to do the obvious work, the toilet relies on directed airflow to pull waste away from the body. For liquid waste, a dedicated hose collects urine, which the crew vents into the vacuum of space several times a day. Solid waste is drawn into a bag inside a sealed canister — and here is where the hands-on part comes in. After each use, the astronaut must manually compress the waste to the bottom of the container to make room for whoever goes next. Those canisters are swapped out a few times over the course of the mission and returned to Earth.
Keeping the rest of the body clean presents its own set of problems. There are no showers aboard Orion. Water in microgravity does not flow; it forms floating globules that drift wherever air currents take them. The crew instead relies on no-rinse soap and carefully rationed water applied directly to skin and hair, followed by toweling off. Every gram of moisture matters: the capsule's humidity management system captures one hundred percent of the water vapor that evaporates from the crew's bodies and recycles it back into the closed-loop system.
The toilet itself offers something that might seem trivial until you consider the context: a door. In a nine-cubic-meter living space shared by four people for ten days, Hansen notes that the hinged enclosure around the toilet is the only location in the entire spacecraft where a crew member can experience a genuine moment of solitude. That small architectural detail — a door that closes — carries a weight that is easy to underestimate when you are not the one hurtling through deep space with three colleagues a few feet away at all times.
The Artemis II mission, which will carry Hansen alongside NASA astronauts Reid Wiseman, Victor Glover, and Christina Koch, is a crewed lunar flyby — the first time humans will travel to the vicinity of the Moon since Apollo 17 in 1972. The ten-day mission is designed to test the Orion capsule and its systems under real deep-space conditions before NASA attempts a lunar landing on Artemis III. Every system aboard, from propulsion to life support to waste management, will be evaluated against what comes next.
As missions grow longer and destinations grow more distant — the Moon first, then eventually Mars — the unglamorous infrastructure of daily human life in space becomes as consequential as any instrument package. A toilet that works reliably, a door that closes, a way to stay clean: these are not footnotes to the story of exploration. They are part of what makes it survivable.
Notable Quotes
The toilet is the only place in the entire spacecraft where a crew member can actually feel alone for a moment.— Jeremy Hansen, Canadian Space Agency astronaut, paraphrased
The Hearth Conversation Another angle on the story
Why does NASA bother explaining the toilet publicly? It seems like an odd thing to highlight.
Because it's the question everyone actually has. Hansen giving a tour of the toilet trainer is a way of saying: we've thought about this, it works, and the people going are going to be okay.
What's the biggest difference between the Apollo approach and what Artemis II will have?
Apollo astronauts used plastic bags. There was no dedicated system at all. The Universal Waste Management System is a closed, airflow-driven mechanism — a genuine toilet, not an improvisation.
The manual compression step sounds unpleasant. Is that really necessary?
In a sealed canister with limited volume and four people sharing it for ten days, yes. Space is finite in every sense of the word up there.
What happens to the urine that gets vented into space?
It disperses into the vacuum. The solid waste canisters come back to Earth — they're part of the mission's return cargo.
The recycled moisture detail is striking. They're essentially drinking reclaimed sweat?
Indirectly, yes. The humidity system captures evaporated water from their bodies and feeds it back into the supply. Nothing is wasted when you're that far from a resupply.
The door being the only private space on the ship — that feels significant beyond just hygiene.
It is. Ten days in nine cubic meters with three other people is psychologically demanding. A door that closes is a small thing that does a lot of work.
How does this connect to longer missions, like a Mars transit?
Artemis II is ten days. A Mars mission would be months. Every lesson learned about waste management, water recycling, and crew comfort in Orion feeds directly into designing systems that could sustain people for much longer durations.