We do know that human excrement is very much real, right? What you may not know is that it could be integral to getting humans to Mars in the near future!
Researchers from Clemson University are studying how to convert molecules from astronauts’ sweat and urine into plastics to subsequently produce tools aboard a spacecraft. The team is working with a strain of yeast called Yarrowia lipolytica. Hypothetically, astronauts would be able to feed it with the carbon and nitrogen in their excrements. The yeast would then act like a “space recycler,” creating oils and fats that can eventually be transformed into bioplastics.
The plan is to engineer Yarrowia lipolytica to produce polyester, which is the material that makes uncomfortable clothing! But on a long trip to Mars, astronauts can feed this plastic into 3D printers, which will theoretically have the capacity to make instruments on request. So if something breaks along the way, no problem! You can whip up a pee tool in no time.
Astronauts on long missions can’t pack a ton of additional gear for their trips. This would make the ship heavier and add to fuel costs expected to shoot the shuttle out of Earth’s orbit. Because long-duration spaceflight will require astronauts to be extra prudent, recycling pee actually makes a lot of sense.
In fact, astronauts have already been doing this in a different capacity aboard the International Space Station (ISS). Things like pee, poo, and hygiene are essential things that can kill mission because of illness. On the other side, it eliminates your consumables!
A recent blog post from the European Space Agency (ESA) explains that the filtering equipment currently used up on the ISS to make fresh water from sweat and urine is quite large and clunky (weighing up to 150 kg), and regularly needs replacing as it gets clogged up with unwanted molecules.
The Aquaporin Space Alliance has come up with a biomimetic “aquamembrane” kit. This bio-inspired solution uses nanotechnology and Aquaporins proteins that control water supply in all living organisms to produce fresh water.
What is cool about these membranes is that they let through water molecules. However, an electrostatic charge ensures that any unwanted ions, including salt, remain behind. This process is called forward-osmosis, where water continuously drifts from one side of the membrane to the other.
Astronauts, space engineers, and mission planners who have to deal with the complex logistics of providing fresh water supply in space hope that this new technology could provide a smaller and lighter water purification method.
Astronaut Andreas Morgensen will be testing three sets of the Aquamembrane kits for the first time when he jets up to the ISS. Morgensen will filter three samples of dirty waste water of about 300 mL each. In theory, he should end up with three purified samples of 50 mL each, which will then be examined back on Earth.
The sooner we can transform astronauts’ excrements into something useful, the closer we get to becoming a multi-planetary species!