How Do Astronauts Use the Toilet in Space?

Spaceflight wasn’t always glamorous, as astronauts had to work around simple Earth tasks in the air. (Stock image.)

There are many questions about space and everything unknown about the world beyond ours. But one of the most frequently asked questions is, How do you use the toilet in space?

The answer is quite simple, space toilets. A space toilet is a urinal designed for a zero-gravity environment. The most basic human biological processes become challenging because in space there is no gravity to help. Airflow directs the collection and retention of liquid and solid waste instead of gravity. Before there were commodes, astronauts would have to wear a urine collection and transfer device. During the Apollo 11 mission in July 1969, astronauts would go to a somewhat private spot on the spaceship, put on the condom-like pouch, and attach a rubber transfer tube with a tank at the end to dispose of their liquid waste. The entire process took a whopping 45 minutes.

The urine collection and transfer device was used during the Apollo 11 mission and is now on display at the National Air and Space Museum. (Image courtesy of Air and Space.)

The urine vented out into space and instantly froze. According to many astronauts, the freezing of the urine and the way it glimmered off stars created a beautiful light show of sorts.

It was harder for astronauts to perform other deeds. Astronauts had to have a high-protein, low-residue diet to minimize their bowel movements. When they did need to relieve themselves, they had to store their feces or vomit into a bag containing a germicide pouch to help destroy microorganisms. They would store the bags in a special compartment on the Command Module, which returned home with them, and left some behind on the surface of the moon.

This method did come with its problems. During the Apollo 10 mission, an escapee from the pouch was found floating in the cabin. (Image courtesy of NASA.)

Weightlessness causes fluid to distribute unevenly in the human body, causing the kidneys to create a physiological reaction that makes astronauts want to relieve themselves within the first two hours of being in space. The space toilet was thus the first device designed for shuttle flights.

Strange Beginnings: The First Generation

In 1973, American astronauts finally got their first sophisticated toilet.

The Skylab lavatory had no resemblance to those found in residential bathrooms. Though it was designed for the crew to eliminate waste and dispose of the remainder, it also had to store samples for biomedical experiments to determine the effects of spaceflight on metabolism and the retention of biochemical substances.

The urinal was situated on the wall in the waste management area and included a fecal-urine collector, collection and sample bags, sampling equipment, odor control filters, and a fan.

It had a hinged, contoured seat connected to a mesh liner where the astronaut inserted a fecal collection bag each time they used the loo. The air would pass through the bag and mesh liner into the fecal collection receptacle and a filter to remove the odor. The fan would then recirculate the air.

The waste management compartment with the fecal-urine collector mounted on the wall. (Image courtesy of NASA.)

A crewman would sit on the seat, fasten a belt across his lap and use handhold and foot restraints to keep him down. The airflow from the fan would separate the fecal matter from his body and into the collection bag.

Crewmen could urinate standing or sitting down through a urine collector, which was a long hose attached to a funnel-like receiver and a urine collection bag. Airflow from a fan would direct the urine. A liquid-gas separator centrifuge would remove the air after the collection was complete.

The crew would collect feces and vomit in bags and then vacuum dry with heat for safekeeping. They could also dump it into the waste tank.

The waste management area also included utility closets full of personal hygiene and house cleaning supplies such as tissues, waste collection bags, soap, and utility wipes.

Russian Roots: The Second Generation

After a series of problems and breakdowns with the Skylab toilet, NASA bought a $19 million Russian one in 2008.

In the early days, Russian engineers built a toilet that worked more like a vacuum cleaner.

The device had a hose with an attached funnel, which was shaped differently for either gender. It was the first time astronauts had to consider designing a restroom for women.

As with prior generations of space toilets, the astronaut would sit on the seat and pull handles over themselves to keep them on the device. A light suction airflow allowed the crew member to separate their waste from their body. A holding tank then stored the liquid or solid waste until it was processed or disposed of along with the station’s other garbage. Crewmembers would put the trash in a capsule and then fire it toward Earth so that it could burn up as it entered the atmosphere.

Mir-era space toilet. (Image courtesy of National Space Centre.)

By the time that host spacecraft Mir retired in 2001, researchers uncovered that the urine dumps were hitting the spacecraft’s solar panels, which caused it to operate at 40 percent of its capacity.

Thus, the International Space Station (ISS) began to modify the Russian potty to recycle the urine into drinking water through a chemical solution called Alternate Urine Pretreatment. With this process, the urine is combined with the solution and other sources of water on the spacecraft, such as condensed humidity from the air, to distill and filter it until it becomes clean drinking water. Through the process, water supply and resupply missions were no longer an issue. The technology can also help us on Earth to find better ways of conserving water and solving shortages.

$30 Million for a Toilet: The Latest Generation

Recently, NASA launched a new space toilet, the Universal Waste Management System (UWMS), to the ISS and Orion. It took NASA six years and $23 million to come up with the design for the new, high-tech porta potty.

The design is universal because it allows the system to adapt to any spacecraft. The loo will feed pretreated urine into a regenerative system, which recycles the urine into water for longer missions or simply stores the waste for disposal for shorter ones via the Urine Transfer System.

The toilet was designed to address astronaut feedback about comfort and ease of use. (Image courtesy of NASA.)

The new commode has a built-in system that uses a highly acidic solution to break down deposits in the urine before it is recycled. NASA’s goal is to recycle 98 percent of urine before the first human missions proposed for Mars transport.

The new toilet works and looks the same as the previous generations, but this time, female crewmembers shared their input to help design the shape and length of the funnel, its position, and the shape of the seat.

The toilets are now 65 percent smaller and 40 percent lighter due to the limited space in Orion. The compact cylinder standing about 28 inches tall features 3D-printed acid-resistant parts made out of materials such as titanium and other durable alloys.

The loo, located within a stall, automatically starts the airflow once its lid is open to pull urine and feces away from the body and into the proper receptacles. It features a specially shaped replaceable funnel and hose for urine or a small and pointy seat for bowel movements, which the crew can use simultaneously. Like before, the system has foot restraints and handholds to keep the astronauts down.

The stall includes a removable waste compactor so that astronauts can deposit their droppings in a baggie and drop it down into the canister. The collection bin holds roughly 30 deposits. The crew place toilet paper, wipes, gloves, and sample waste in watertight bags.

Though astronauts may feel awkward using the new device, it is sure to get a lot of use over the next several months as more Americans go into space.