The Physics of Bathing
Showers, baths, swimming: these are all experiences most of us take for granted on Earth. There's nothing quite like experiencing the cool touch of water from the shower or jumping into a pool on a hot day. Gravity is what makes all of these experiences possible—it pushes that cool and refreshing water off your back and into the drain.

But all that changes in space. The lack of gravity causes water and soapsuds to stick to everything.

So how does one bathe in space? (Hint: It’s not nearly as comfortable as it is here on Earth.)

Gemini and Apollo Missions
On the Gemini and Apollo missions, NASA went for the simplest solution: a sponge bath. Astronauts cleaned themselves with a towel, soap, and a little water. Unlike later missions, there was no way to conserve water. Astronauts could only use limited amounts of water to clean themselves, and that meant coming back to Earth smelling a little less like roses.

“The astronauts had been in their suits so long without changing their clothes so that the scent lingered the entire time,” said Jennifer Levasseur, a curator in the Museum’s Space History Department. “It was a slap in the face to those who greeted them upon their return because the scent was so strong.”

Showering on the Skylab
NASA wanted to make Skylab, the United States’ first space station, feel more like home, especially because astronauts would be living there for extended periods. Although designers had to add equipment within a very confined space, they did add a toilet, an exercise area, and a shower.

Astronauts took cumbersome showers in a tube-like contraption. To make sure they did not float away, astronauts put their feet in foot restraints at the base of the shower. Then they attached a pressurized portable bottle of water to the ceiling, which connected to a hose and showerhead.

The astronauts then pulled a fireproof, cylinder-shaped shower wall up from the floor and attached it to the ceiling. Then it was shower time! They lathered liquid soap all over themselves and sprayed water through the push-button showerhead. Then they had to suction up suds and water into a collection bin; wayward water could pose a hazard to the electronics and instruments on the space station.

NASA strictly rationed water and liquid soap on Skylab  — a New York Times article said each astronaut was given approximately six pints of water per shower.

From start to finish, a shower on Skylab took over two hours on average.

Some astronauts thought the process was inconvenient. Others liked having the comforts of Earth while in space. The first astronaut to use the shower, Paul Weitz, reported, "It took a fair amount longer to use than you might expect, but you came out smelling good."

Showering on the Shuttle and International Space Station  
On the Space Shuttle and International Space Station (ISS), astronauts went back to the “old-fashioned” way of bathing in space. On the ISS, astronauts do not shower but rather use liquid soap, water, and rinseless shampoo. They squeeze liquid soap and water from pouches onto their skin. Then they use rinseless soap with a little water to clean their hair. They use towels to wipe off the excess water. An airflow system nearby quickly evaporates excess water. (See this video of astronaut Karen Nyberg washing her hair in space.)

How do they always have enough water to shower? Because not a drop is wasted. The water on the ISS is constantly being recycled. Water sources — like a crewmembers’ breath moisture or even their urine — is purified through a filter, so it can be used over and over again.

Having astronauts sponge bathe is not only simpler, but it is also cost-effective, Levasseur said.

“If there was a solution that already worked, it was easier to go with that existing solution rather than to spend a lot more money on something that would just cost more money, take up more space, and be heavier,” she said.

Levasseur also noted that many astronauts when they first arrive on the ISS say that there is a particular smell to the station. “It has that lived-in smell,” she said

Would You Shower in Space?
Human ingenuity has gotten us into space, and it even enables us to conserve water efficiently on the ISS. But is it bearable? Astronaut Mike Hopkins, stationed on the ISS from September 2013 to March 2014, told The Atlantic that when exercising in space, he missed the shower. “Up there, the sweat sticks to you—you have pools of sweat on your arms, your head, around your eyes. Once in a while, a glob of it will go flying off,” he said.

Hopkins is not alone in missing water. Many astronauts find rainstorms comforting when they return to Earth because water, which they had precious little of in space, falls all over them. Scott Kelly, when he returned to Earth after a year in space, jumped into a swimming pool with all his clothes on.

“It gives them an instant sense of gravity, the principle of gravity that they don’t have on the space station,” Levasseur said.

Now, let’s hear from you: Could you live without a shower for several months straight to experience living and working in space?