Question: How do astronauts maintain personal hygiene in space? Obviously they can’t shower, so I’m guessing they have to do something like a sponge bath? — WT, Fargo, ND
Answer: You’re correct that a “normal” shower wouldn’t work. In a microgravity environment water would scatter off your body and float around. Without gravity there is no “down” so normal drains wouldn’t work. And with all the electrical equipment aboard the ISS, you do not want water floating around.
But if the shower is totally enclosed, and proper protocols are followed, you can indeed shower in space. The video shows how it’s done. I’m not sure if this is just a demo being done on Earth, perhaps at Johnson Space Center, or an early version shower on the ISS. At times the astronaut seems to be held to the floor firmly by gravity, and at other times she seems to be floating weightless. It’s certainly not a replica of the shower currently in use on the ISS. Either way, the operating instructions are the same.
In microgravity, as on Earth, water will still stick to your skin and hair because of adhesion. Note that the bathing suit is not necessary when taking a real shower. This is a demo. Some astronauts prefer to apply the water to a wash cloth first and wet their body that way. The water is delivered through a flexible tube at low pressure to minimize the scattering of droplets. After that, the application of soap and shampoo proceeds as normal.
The big difference comes when the shower is done. There’s a second flexible tube that operates as a vacuum to pull water off your body, as well as the inside surfaces of the enclosure. Only when the shower is dry are you allowed to open the door. Further drying yourself with a towel will still be necessary.
As you can see in the video, water that is vacuumed out of the shower is fed to a recycling system to be purified and reused. Water is a precious resource on the ISS so it is never “flushed down the drain.”
The ISS shower is actually a pretty simple system, and easy to maintain. The ISS toilet, by comparison, is a highly complex system that cost $23M over 6 years to develop — and there are still occasional glitches. If you’re curious how it works, NASA has a great explanation with diagrams here.
Astronauts have to give up some of the comforts of home during long duration missions. But NASA has some of the best engineers in the world, and they’ve done an excellent job keeping astronauts safe and healthy.
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