How astronauts could turn human waste into usable products

SpaceX's Dragon capsule approaches the International Space Station. Photo / AP file

Astronauts could turn their own body waste into tools and supplements allowing them to boldly go further into space than ever before.

Researchers have proven that it is possible to harvest vital molecules from urine, faeces and exhaled breath which can be repurposed into 3D printable plastics or nutrients.

Astronauts cannot take a lot of spare parts into space because every extra ounce adds to the cost of escaping Earth's gravity.

But scientists at Clemson University in South Carolina have discovered strains of yeast that can break down human waste into useful products.

One strain, when fed with urea from untreated urine and CO2 from exhaled breath produces omega-3 fatty acids which contribute to heart, eye and brain health.

Another has been engineered to make polyester polymers. Those polymers could then be used in a 3-D printer to generate new plastic parts.

So if a tool was lost on a spacewalk, a new one could simply be printed from the molecules extracted from waste.

"If astronauts are going to make journeys that span several years, we'll need to find a way to reuse and recycle everything they bring with them," said Dr Mark Blenner, of Clemson University. "Atom economy will become really important."

Researchers hope the project will eventually allow astronauts to live for large amounts of time in space.

Already Nasa and the European Space Agency are planning to establish bases on the Moon and further afield, but being in space for years at a time will require far more recycling of waste.

Elon Musk, the SpaceX founder, has laid out plans for a colony on Mars within the next 50 years, and has warned that humans will need to leave Earth to avoid a "doomsday event" such as an asteroid strike.

For now, the engineered yeast strains can produce only small amounts of polyesters or nutrients, but the scientists are working on boosting output. They're also looking into applications on Earth, in fish farming and human nutrition.

The research was presented at the American Chemical Society's annual meeting.