On NASA's moon mission, the biggest headache has been the toilet

Loren Grush, Bloomberg News on Apr 5, 2026

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As NASA’s Artemis II astronauts make their way to the moon this weekend, their test flight has gone surprisingly well without any major issues, save for one piece of technology giving the crew some grief: the toilet.

The Lockheed Martin-built Orion crew capsule that’s carrying the Artemis II crew to the moon is equipped with what’s known as the Universal Waste Management System for the astronauts to use during the 10-day mission. It’s roughly the same space toilet that’s used on the International Space Station.

But getting the complicated piece of equipment to work properly during the flight has become a recurring issue.

The UWMS comes equipped with a funnel and hose for urination, and there is a seat with a hole for bowel movements. Since the astronauts are in microgravity, the toilet relies on air flow that pulls waste into the toilet and ensures the capsule stays clean. The astronauts can also use footstraps and handles to stay in position.

On Artemis II’s first flight day, the toilet indicated an issue right after the crew got to space. Mission specialist Christina Koch, who proudly declared herself the “space plumber,” was able to get the toilet working again with some help from Mission Control.

It turned out to be a problem with the toilet’s pump, which needed extra water to be wet enough and primed for use.

“Once we figured out that we didn’t put enough water in, we put more in there, made sure that it was essentially primed – the pump was primed – and then the toilet came right back up,” said Judd Frieling, the ascent flight director for Artemis II.

Not so fast.

The toilet once again started acting up. Unlike on the International Space Station, where wastewater is contained, treated and recycled in a closed loop system, the wastewater on the Artemis II mission is periodically dumped overboard throughout the mission. During these dumps, gleaming particles stream across the window of Orion, as seen by video taken by the crew.

One of those wastewater dumps stopped prematurely. NASA suspected that a buildup of ice may have been blocking the vent nozzle that allows the wastewater to drain out into space.

As NASA troubleshot the issue, the agency determined that the crew shouldn’t use the toilet for urination to be safe.

“Copy, we are ‘no go’ for toilet,” Koch acknowledged at one point.

The problem is there only so much room for urine to collect.

“The urine tank that is in the vehicle is only about the size of a small, like your office trash can,” Debbie Korth, NASA’s Orion deputy program manager, said during a news conference. “So we want to make sure we can empty it out before we put anything else in there.”

However, the crew was still “go” for bowel movements, as those waste materials are collected in water-tight bags. And as a backup for urination, the crew could still use what are known as Collapsible Contingency Urinals, which are long tube-like containers that are designed to control the flow of liquids.

“We can do a lot of extraordinary things in space right now, but nailing this capability is one that we need to certainly work on,” NASA Administrator Jared Isaacman said Sunday on CNN’s State of the Union.

Solar Rays

Icy toilet issues have happened before in space.

The crew of the Space Shuttle mission STS-41-D in 1984 famously had to use backup bags when their toilet went down. The culprit turned out to be a buildup of ice that jutted out from the toilet’s vent. The crew got rid of it be using the Shuttle’s robotic arm to knock it away, but that didn’t save them from using bags for a good portion of the mission.

To fix the Artemis II issue, NASA decided to warm things up. The agency positioned Orion so that the toilet vent would “bake” in the sun for a few hours and melt some of the ice. That seemed to do the trick. The crew conducted a few wastewater dumps to test if the plan worked, with one showing limited flow at first.

But finally late on Saturday, the crew got some good news from Mission Control.

“Breaking news,” a communicator in NASA’s Johnson Space Center said to the crew. “We have results on the discussions down here for the tank venting, and at this time, you are ‘go’ for all types of uses of the toilet.”