SpaceX’s Broken Toilet Meant Diapers or Hold It for NASA Crew

Last week, the SpaceX Crew-2 capsule was all clear to make its trek back home, but one thing stood in the way: its toilet. While the vehicle had been cleared to return to Earth, the toilet remained offline for the duration of the trip.

If the astronauts needed to go, they had to hold it, or use astronaut-grade diapers built into their flight suits as a contingency.

“Of course that’s suboptimal, but we are prepared to manage that in the time that we’re onboard Dragon on the way home,” K. Megan McArthur, the Crew-2 mission pilot, said during a news conference on Friday.

The acorn-shaped capsule is somewhat larger than a minivan on Earth; it doesn’t have a proper bathroom. Instead it has a toilet device with a tube and fans built into one of the spacecraft’s compartments that create suction to ensure waste goes in the right direction in the weightlessness of space.

In September, SpaceX detected a leaky toilet on another one of its capsules during the flight of Inspiration4, a three-day orbital journey of private astronauts that didn’t dock at the space station, according to Bill Gerstenmaier, a company vice president who discussed the toilet problems during a news conference in October.

A tube from the capsule’s toilet that funnels waste into an internal tank broke loose and leaked fluids into a fan, which sent urine throughout an area beneath the capsule’s interior floor, Mr. Gerstenmaier said.

When SpaceX engineers discovered the flaw, they instructed astronauts on the space station to inspect their Crew-2 capsule. They found similar traces of urine beneath the interior floor, which worried officials that it could corrode some of the capsule’s aluminum parts and pose a safety risk for the return flight.

SpaceX engineers conducted experiments on the ground to test whether urine, which is mixed with an ammonia-removing compound called oxone, could corrode the aluminum. The parts sat in a chamber that mimicked the humidity conditions aboard the space station for “an extended period of time,” Mr. Gerstenmaier said.

From the experiment and inspections of the Inspiration4 capsule, SpaceX found that the urine-oxone mixture had little effect on the aluminum parts because of heavy coats of paint on Crew Dragon that are “a great blocking agent to the liquid,” Sarah Walker, SpaceX’s mission management director for Crew Dragon, told reporters during a news conference.

“We learned that the liquid evaporates within just a couple days,” Ms. Walker added, “and that really limits the impact that we observed when we were doing all of our post-flight inspections.”

NASA officials approved the results of the experiments and deemed Crew-2 safe to return to Earth. SpaceX proposed a permanent fix to future Crew Dragon capsules that should ensure the urine tube would not come undone.

But the toilet leak on the Crew-2 capsule remained, meaning that astronauts heeding the call of nature in orbit needed to use the “undergarments” in their flight suits, Steve Stich, NASA’s Commercial Crew program manager, told reporters on Oct. 31.

“Our intent is to not use the system at all for the return leg home, because of what we’ve seen with the fluid,” Mr. Stich said. “Any time the crew is suited, they use an undergarment in that suit, and it’s a short mission coming home so it’s pretty typical to have an undergarment on and they can use that on the way home.”

“Spaceflight is full of lots of little challenges,” Dr. McArthur said. “This is just one more that we’ll encounter and take care of on our mission.”

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