Astronauts aboard the International Space Station have managed to recycle 98 per cent of their urine and sweat into drinking water, Nasa has announced – a major boost for global space aspirations.
The news is being heralded as a significant step forward in plans to launch long-term missions to the Moon and beyond.
While the idea might make some uneasy, Nasa says the drinking water produced is cleaner than that found back on Earth.
The unique recycling efforts are crucial to help scientists develop life support systems that can use existing resources to produce water, food and air during long-haul missions.
“For space missions that venture beyond low-Earth orbit, new challenges include how to provide basic needs for crew members without resupply missions from the ground,” Nasa said in a statement.
“Nasa is developing life support systems that can regenerate or recycle consumables such as food, air and water, and is testing them on the International Space Station.”
The Environmental Control and Life Support System, the recycling technology on board the station, was recently able to recover 98 per cent of wastewater, beating a previous record of between 93 to 94 per cent.
“Ideally, life support systems need to recover close to 98 per cent of the water that crews bring along at the start of a long journey,” the Nasa statement added.
An important step forward
The ECLSS technology is a combination of hardware that includes a water recovery system, which collects wastewater and sends it to the water processor assembly to produce drinkable liquid.
“The processing is fundamentally similar to some terrestrial water distribution systems, just done in microgravity,” said Jill Williamson, the ECLSS water subsystems manager.
“The crew is not drinking urine – they are drinking water that has been reclaimed, filtered and cleaned such that it is cleaner than what we drink here on Earth.
“We have a lot of processes in place and a lot of ground testing to provide confidence that we are producing clean, potable water.”
To store astronauts' breath and sweat, the hardware uses advances dehumidifiers to capture moisture released into the cabin.
The urine processor assembly unit recovers water using vacuum distillation, and a brine – or extremely salty water – processor was recently added to increase the water recovery rate.
“This is a very important step forward in the evolution of life support systems,” said Christopher Brown, part of the team at Johnson Space Centre that manages the space station’s life support system.
“Let’s say you collect 100 pounds [45.3kg] of water on the station. You lose two pounds [0.9kg] of that and the other 98 per cent just keeps going around and around.
“Keeping that running is a pretty awesome achievement.”
All the collected water is treated by the water processing assembly technology, which first uses a series of specialised filters and then a catalytic reactor to break down any trace contaminants that remain, Nasa said.
Sensors check the water purity and unacceptable water is reprocessed.
The system also adds iodine to the acceptable water to prevent microbial growth and stores it for the crew to use.
Nasa said that each crew member needs about 3.7 litres of water per day for consumption, food preparation and hygiene, such as brushing teeth.
