Revolutionizing waste management in space
A dirty secret in space travel is that astronauts have been known to use diapers while wearing spacesuits. However, a new design promises to recycle valuable water while also offering a more hygienic approach to spacewalks.
When inside the International Space Station, astronauts use a Urine Processor Assembly to recover water from pee by vacuum distillation, according to NASA. Because water is so important, life support systems try to recover over 98% of the water that the crew brings.
Life support
Outside the spacecraft, spacewalks may take many hours, and astronauts wear “maximum absorbency garments”. As explained here, these MAGs have been in use since the 1970s and are made of many layers of superabsorbent polymer. To put it briefly, everything that is inside them is diapers, and nothing is recycled.
A new concept in full-body “stillsuits,” was influenced by the Dune film series. In the movies, some spacesuits clean drinking water by absorbing water lost through pee and sweat.
Water recovery
The “stillsuit” prototypes, described by Cornell University researchers in a publication in Frontiers in Space Technologies, make use of a special urine collection and filtration system specifically designed for spacesuits.
“The MAG has reportedly leaked and caused health issues such as urinary tract infections and gastrointestinal distress,” according to Sofia Etlin, the study’s first author and a research staff member at Weill Cornell Medicine and Cornell University. Additionally, astronauts currently have only one liter of water available in their in-suit drink bags.
That is not much for spacewalks lasting many hours. It is significantly less when you take into account NASA‘s intention to include longer spacewalks on the moon as part of their highly ambitious Artemis lunar missions. In an emergency, astronauts ought to be able to perform a spacewalk for a whole day, according to Etlin. Plans call for many astronauts to conduct lunar spacewalks on at least four Artemis missions.
Taking a pee
A urine collection device wrapped in polyester microfiber is part of the ‘stillsuit’. It consists of an undergarment with several flexible fabric layers attached to a silicone collection cup that is molded. As a result, astronauts of different genders would need to employ different sizes and shapes. When moisture is detected by an RFID tag connected to an absorbent hydrogel, a pump is activated. It takes only five minutes to collect and purify 500 ml of pee, and the researchers claim that it is 86% efficient because it is designed for microgravity.
“The design includes a vacuum-based external catheter leading to a combined forward-reverse osmosis unit, providing a continuous supply of potable water with multiple safety mechanisms to ensure astronaut wellbeing,” said Etlin. Another idea is to provide astronauts with their own supply of high-energy, non-caffeinated drinks.
