Composting Toilets and Human Waste in Space

One of the most popular movies of 2015 was a story about one man’s struggle, not only in a hostile environment doing everything it could to kill him, but with himself. We’re talking of course about The Martian, a Ridley Scott (Alien, Blade Runner, Black Hawk Down, Gladiator and many more) film based on the highly successful novel of the same name by Andy Weir.

Matt Damon, playing the character of Mark Watney finds himself left behind on Mars when he and his crew are hit by a colossal storm. Watney is struck by debri and his crew (mistakenly taking him for dead) are required to hastily depart the planet.

Waking up injured and alone, he quickly realises that his only chance for rescue arrives in four years’ time when the next scheduled mission is set to land on the red planet. He would need to survive, by himself, grow and harvest enough food to stay alive to meet the ship in 1460 earth days.

Recycling everything he has, reusing and repurposing as much as possible he has to focus all his botanical and scientific knowledge to the task of just surviving on the hostile environs of Mars.

One of the iconic lines from the movie, comes as Watney realises his dire predicament and mutters the now famous line “In the face of overwhelming odds, I’m left with only one option. I’m going to have to science this shit out of this”.

Despite staggering odds against him, Watney figuratively and literally ‘sciences the shit’ out of everything he has, including his own shit!

This line is what we love about Watney’s character in the movie. An unyielding approach to survive and never give up. It also gives us pause to think about human ingenuity and how we can prosper here on Earth and on other planets or colonies like Mars.


One of the overarching themes throughout the movie is sustainability and ingenuity. To be able to survive in space today’s astronauts recycle almost everything and find dual purposes for many items we take for granted here on earth. For example astronauts on board the International Space Station (ISS) recycle up to 93% of water on board, including re-purposing their own urine and showering water (read, convert it to drinking water).


With planned trips to Mars, it makes sense to ensure that recycling and reusing as much as possible is a point of focus for astronauts as the 8 months trip means taking everything you need along with you.

Practising on Earth for Life on Mars

A manned mission to Mars is something that fills the heads of many science fiction lovers and star gazers alike. The red planet is our nearest neighbour and exploring this planet in person is now looking to become a reality.

With plans to go to Mars coming from groups like Mars One and now NASA’s Pioneering Next Steps in Space Exploration it seems like getting people on the red planet is more likely to become a reality.

In fact, many organisations have already begun planning and taking steps to get ready for the next great migration of humankind. Take the Hawaii Space Exploration Analog and Simulation (HI-SEAS) project. They’ve recently completed a year long trial where five would-be martians lived together in small domed habitats for a year. One of the ways they ensured the site was as eco friendly as possible was to install a Sunmar composting toilet.

If we as a species are going to travel to the far flung corners of the galaxy, we’re going to be forced to reshape the way we grow food, treat waste and recycle what we produce. Composting toilets are just one cog in the very complex machine of space exploration but it does make you think, if we’re pushing the boundaries of what we can do in space, why aren’t we doing it here on Earth?

Now we’re not saying that you should start re-purposing your own urine into drinking water (yet), but we’re asking you to think about the footprint you leave here on Earth.
How much valuable drinking water are you wasting every time you flush a toilet?

A composting toilet is an easy and simple way to do your part for Mother Earth, without having to drink your own urine, or live off potatoes for a year like Mark Watney.