Sanitation in zero gravity - Leaky space toilets: SpaceX’s latest engineering challenge

SpaceX ran into trouble with the toilet system of Crew Dragon, its astronaut capsule, last month during Inspiration4, its first mission carrying a fully private crew of four people to orbit. At some point during the three-day mission, there was a problem with Crew Dragon’s toilet. 

The nature of the toilet problem, though, seemed cloaked in secrecy. Mission managers deflected when pressed for details. SpaceX didn’t respond to questions for comment. Scott Poteet, the mission’s director on Earth, said in a news conference with reporters only that there were “issues” with the capsule’s waste management system. 

Jared Isaacman, the Inspiration4 mission commander, told CNN, “Nobody really wants to get into the gory details.” 

Crew Dragon has more interior space than a minivan, but less than a studio apartment, and there is no proper bathroom. Instead, it has a device on its ceiling that astronauts use to relieve themselves — remember, there’s no up or down in microgravity. The device creates suction using an internal fan, crucial to ensuring human waste goes in the right direction in the weightlessness of space. Some officials vaguely said the toilet problem involved the fan, prompting even more questions.A tube that funnels urine into a tank broke loose during the Inspiration4 mission and leaked into the fan, which sprayed the urine in an enclosed area beneath Crew Dragon’s floor, Bill Gerstenmaier, a SpaceX official who once oversaw human spaceflight for NASA, told reporters on Monday night. He said the four passengers didn’t notice anything was wrong during the mission. 

“We didn’t really even notice it, the crew didn’t even notice it, until we got back,” Gerstenmaier said. “When we got the vehicle back, we looked under the floor and saw the fact that there was contamination underneath the floor of Inspiration4.” 

SpaceX completed a fix for the toilet aboard the capsule being used for Sunday’s launch. The redesign means there are no tubes that could come “unglued” as they did during the Inspiration4 flight, Gerstenmaier said. NASA is expected to sign off on the new design on Friday. 

But the toilet predicaments haven’t stopped there. Another Crew Dragon capsule that docked to the space station in April with four astronauts aboard has the same plumbing system as the Inspiration4 capsule. SpaceX engineers feared the same “contamination” might have occurred on that spacecraft. The engineers’ suspicions were correct. 

Toilets are crucial to NASA’s space exploration ambitions as the agency aims to trek beyond the space station, toward the moon and eventually Mars. Last year, the agency launched to the space station a new $24 million toilet, the Universal Waste Management System. It uses a suction method similar to Crew Dragon’s, mixing urine with an acidic solution before recycling the liquid for drinking water. (Solid waste is disposed of in bags that are stored and eventually fired into space.) 

Roulette is a reporter with NYT©2021 

The New York Times