China develops detergent-free washing machine for astronauts that uses mist, ozoneMrigakshi Dixit
Interesting EngineeringTue, September 2, 2025 at 9:31 AM EDT
3 min read
For astronauts, dirty laundry has always been a major issue in space. With no washing machines and very limited water, they wear clothes until they can't anymore, then discard them.
But, they may soon be able to enjoy the luxury of clean clothes in space, thanks to a new washing machine-like system developed by the China Astronaut Research and Training Centre.
Researchers have reportedly developed a compact, detergent-free washing machine.
The cube-shaped device is said to be a bit larger than a suitcase, weighing 12 kg (26 lbs).
According to the South China Morning Post, washing machines use mist and ozone to clean clothes, which requires almost no water.
The lack of waterThe problem is simple: water. It is a precious resource on the International Space Station (ISS) and China’s Tiangong space station.
Every drop is carefully recycled, leaving none for washing clothes.
Astronauts get most of their water from an advanced water recycling system that collects and purifies wastewater. This includes water from their breath, sweat, urine, and showers.
The recycled water is prioritised mostly for drinking and hygiene.
Furthermore, transporting water from Earth is incredibly expensive due to its weight and the energy required for launch.
Although the space station is without dirt and mud, astronauts' clothes get dirty from sweat during their daily exercise.
After the clothes turn smelly, the astronauts pack into cargo capsules for re-entering Earth's atmosphere, where they burn up.
To prevent the need for astronauts to throw away their clothing, space agencies are exploring ways to launder it in space.
Past attempts to solve this problem include a 2021 test by Tide using special detergent and wipes on the ISS, and a 2023 proposal from Ultrasonic to use vibrations and minimal water to clean clothes, though this method failed to eliminate bacteria.
Well-suited for microgravityChina's new approach is uniquely suited for the space environment.
Reportedly, the device uses just 400ml of water per cycle, delivered as an ultra-fine mist, to clean up to 800 grams of clothing.
Rather than using detergent, the machine produces ozone with ultraviolet light to powerfully disinfect clothes, sterilizing them for up to five uses.
The device's design is well-suited for microgravity, preventing issues like pooling liquids and soapy wastewater.
It could be useful for astronauts on missions lasting longer than five months in orbit or 2.5 months in deep space.
The system uses a 30-minute cleaning cycle inside a sealed chamber.
It works by first spraying clothes with an ultra-fine mist, then releasing ozone for disinfection. Heated air dries the clothes and breaks down the ozone, with sensors and filters ensuring no harmful gases or droplets are released.
Simulations showed a 99.9% sterilization rate.
The researchers designed the system to last at least five years, with future plans to build a prototype and improve efficiency for longer space missions.
According to the researchers, their system could reduce the weight of clothing needed for space missions by over 60%.
Moreover, the significant energy required to launch mass into orbit makes every kilogram of water an expensive commodity.
The team concluded that developing on-board laundry technology is essential for future long-term missions to the moon or Mars to reduce the massive amount of clothing that must be launched from Earth.
The new washing machine has been
described in the Chinese Journal of Space Science.
https://www.yahoo.com/news/articles/china-develops-detergent-free-washing-133127021.html
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