Urine Recycling Makes Mars Travel Easier

astronauts

By Mona Simpson

Did you know that people urinate about 50% more liquid each day than they drink? How, you may ask? Well, part of it is because your body turns some of your food into water. Burning carbohydrates creates energy, as well as some carbon dioxide and water, which adds to the water that your body ingests.

Water consumption is important here on earth, but it is even more critical to make sure you have sufficient water when you’re an astronaut isolated in space. It costs a great deal (up to $10,000 per pound) to deliver supplies to places like the International Space Station, and astronauts who perform long-term space missions, such as traveling to Mars, will need to be able to reuse and recycle the items they take with them in order to reduce cargo. Human wastewater could be over 50% of the total waste per person on lengthy space missions.

There are three sources of water that scientists reclaim and reuse: humidity condensate, hygiene water, and urine wastewater. Since 2010, astronauts living aboard the international space station have been recycling their wastewater, including urine, in real time. Now researchers have found a more efficient method. This research showed that it was possible to turn wastewater into purified water more efficiently — and get energy as well.

The new system uses a chemical process called osmosis to remove water from the urine. Urea remains behind. Urea could be used as a fertilizer or as a raw ingredient in some fuel systems. But in this case, enzymes in the bioreactor tank convert the remaining urea into ammonia. That ammonia drives a fuel cell, using chemicals to produce electricity.

Now before you turn up your nose at the idea of drinking recycled wastewater, you should note that the water the astronauts purify is likely more pure than than the water you drink each day.

Now, this technology can allow astronauts, well as people in developing countries— where water is scarce, to have an even more efficient system to purify wastewater, and an energy source as well. 

Classroom Discussion

  • What is a proof of concept?
  • How much water have you used today? How much water does the average household use each day?