The four crew members of NASA’s historic Artemis 2 mission around the Moon may be on one of the most epic journeys in human history — but they’re already encountering noisome sewage issues inside their cramped capsule.

NASA’s director of flight operations, Norm Knight, told reporters that a controller issue had caused the fan of the space agency’s newfangled Universal Waste Management System (UWMS) — the spacecraft’s toilet, in regular language — to jam.

That meant that the crew members were temporarily only able to use the toilet for Number Two, not One, before finally getting it fixed hours later.

“In the meantime they’re getting their contingency — their backup waste management capabilities specifically for urine,” NASA spokesperson Gary Jordan said during the space agency’s livestream, as quoted by Space.com. “The fecal collection of the toilet, that specific capability, can still be used with the waste management system aboard Orion.”

The “Collapsible Contingency Urinal” eventually filled up and needed to be emptied.

It’s an unfortunate development, considering the UWMS was specifically designed to move on from the horror stories of NASA’s Apollo missions. During early trips to the Moon, astronauts had to deal with leaks, and even a “turd floating through the air” during Apollo 8.

Fortunately, NASA astronaut Christina Koch reported some good news hours later after being walked through how to implement a fix.

“Houston, Integrity, good checkout,” she said.

“Happy to report that toilet is go for use,” mission control radioed back, deploying some euphemistic language: “We do recommend letting the system get to operating speed before donating fluid, and then letting it run a little bit after donation.”

Despite the mishap, the UWMS is still a major upgrade over what Apollo astronauts had to cope with. For one, there was no toilet back then, forcing crew members to both pee and poop in plastic bags. The former was vented out, while the latter had to be stowed.

While the Artemis 2 has a toilet seat, the collected fecal matter will still need to be stowed inside plastic bags and taken back to Earth. However, Apollo crews that reached the lunar waste left their poop there, resulting in a total of 96 bags of waste across six landing sites.

Best of all, the UWMS is inside a trap-door like compartment under the floor, or “hygiene bay,” giving crew members some much-needed privacy while they do their business.

The space WC features a urine collection funnel and a bag-lined toilet seat that uses air to suction waste away from the body, not unlike the one on board the International Space Station.

“The one place that we can go on our mission where we can feel like we’re alone for a moment,” Canadian astronaut and Artemis 2 mission specialist Jeremy Hansen said in a short video about the facility shared by the Canadian Space Agency last year.

More on space toilets: Space Toilet No Longer Oozes Human Pee, SpaceX Proclaims