[Reading Science] In Space, Even the Moisture in Urine Powder Is Extracted

NASA Develops Technology to Recover and Recycle Up to 98% of Used Water
Enables Water Recovery from Residue in Urine Distillation
"Useful for Mars Exploration and Other Missions Without Resupply"

For people embarking on long-distance journeys, the supply of water and food is a crucial challenge. This was also true during the Age of Exploration in the 15th and 16th centuries, which changed history with the discovery of the New World. Salted meat, ship biscuits, and sauerkraut (salted cabbage) were invented to be eaten on board for extended periods. Cold brew coffee and rum also originated during this time. In the 21st century, humanity faces similar challenges as it aims to travel beyond Earth into space. A trip to Mars requires being confined in a cramped spacecraft for at least 6 months to a year. A high-quality, balanced diet and clean water supply are essential. Weight, maintenance, and cost must also be minimized.

The U.S. National Aeronautics and Space Administration (NASA) recently succeeded in an experiment with a urine recycling device (BPA) on the International Space Station (ISS). Photo by NASA website.

In this regard, NASA recently attracted attention by developing technology that recycles and reuses 98% of the water used, "squeezing out every drop of urine."

On the 20th (local time), NASA announced that it successfully tested this technology through the Environmental Control and Life Support System (ECLSS) on the International Space Station (ISS). The ECLSS includes a water recycling system that collects water used by astronauts and sends it to the Water Processor Assembly (WPA) for purification to a drinkable level. It is equipped with a high-performance dehumidifier that even captures moisture released into the air from astronauts' breathing and sweat, converting it into water. There is also a Urine Processor Assembly (UPA) that processes astronauts' urine by distilling it in a vacuum to convert it into purified water.

NASA has succeeded in upgrading the functionality of the ECLSS equipment. The existing urine processing device installed on the ISS purified urine but still discarded a small amount of water contained in the residue (salts). To improve this, NASA developed a new device called the Brine Processor Assembly (BPA) and recently installed it on the ISS. Using the BPA, NASA succeeded in recycling 98% of the water used. The previous recycling rate was about 93-94%. The BPA works by filtering the brine from the UPA through a special membrane once more, then evaporating the water content by exposing it to hot, dry air.

This water vapor is collected by the ISS's high-performance dehumidifier and recycled through the WPA. The WPA uses special filters to remove foreign substances and employs a catalytic reactor to decompose and eliminate even fine contaminants. Sensors are installed to check water quality and reprocess water that exceeds standards. There is also a device that adds iodine to prevent microbial growth and enable long-term storage. On the ISS, each astronaut consumes about 1 gallon (3.786 liters) of water per day, mainly used for food preparation, brushing teeth, and other hygiene activities.

Some may feel uncomfortable with the idea of recycling urine to produce drinking water. However, NASA emphasizes that this water is cleaner than any tap water produced on Earth and that the system is designed to operate for long periods without maintenance or part replacement since it is installed inside the spacecraft.

Jill Williamson, the NASA official who developed this system, explained, "In exploration missions where resupply is impossible, all resources needed by the crew must be recovered and recycled. This allows carrying less water and oxygen, increasing the scientific mission's duration, and enables the crew to focus on mission objectives without worry."