Human waste will pose a huge problem for future space colonization of the solar system

The next time you see a shooting star, there’s a small chance it’s real trash. It’s not a knock on meteors or comets out there. It’s the truth. To deal with the waste that accumulates on the International Space Station, astronauts put it in large trash cans and dump it into the Earth’s atmosphere where everything burns in a burst of glory.

It’s not the greenest system for disposing of space junk, and it raises questions about what kind of impact we’re creating by adding junk and gases to an already strained atmosphere on Earth. But it’s the only one we currently have.

That could soon change if Steve Sepka has anything to do with it.

“One of the best ways to deal with garbage and waste is to compact it,” Sepka, NASA’s project manager for the garbage compaction and processing system, told The Daily Beast. “But there are also a lot of space issues because we have limited power, volume and mass. You also want to be able to remove liquids and process or reuse them. »

One project NASA is currently working on is a compaction system that could turn astronaut waste into tiles that can then be used for practical applications such as radiation shielding. Such an approach fits with a relevant philosophy here on Earth, but especially important if you’re an astronaut weeks or even months away from a crucial resupply mission: reduce, reuse, recycle.

Sepka most recently served as the lead for NASA’s Waste to Base Materials Challenge, held last spring. It was a call for citizen scientists around the world to come up with new ideas and concepts for turning astronaut trash on places like the moon or Mars into usable material.

“We’ve looked at everything from fecal waste and what to do with it, to plastics and litter. Anything we can do to reuse it, recycle it and reuse it.”

— Steve Sepka

The focus was on sustainability. Future astronauts on a place like Mars cannot always rely on regular resupply missions. As such, they must be able to reuse whatever materials they have.

“We looked at everything from fecal waste and what to do with it, to plastics and litter,” he said. “Anything we can do to reuse it, recycle it and reuse it.”

The challenge marked the beginning of answering a question that is becoming increasingly relevant as NASA embarks on its audacious goal of returning to the Moon and, eventually, Mars and beyond: what do we do? do we do with all our extraterrestrial waste? After all, astronauts won’t be able to simply send it back to Earth like those on the ISS.

The challenge generated a variety of interesting solutions ranging from using cotton from old astronaut clothing or even packing moss and urine to grow plants in a hydroponic system, to using algae to convert carbon dioxide into oxygen.

Undoubtedly, the grossest category of the challenge concerned what to do with faecal waste. An example is fermenting feces in order to break them down. The idea is “to achieve anaerobic decomposition very similar to what happens with composting,” Sepka said. “We get microbes to do it and what to do with the leftover materials. It’s very similar to what we do on Earth.

Another involved using poop as a natural fertilizer, like Mark Watney growing potatoes in The Martian. As with so much science fiction before, there could be real-world use cases once researchers and engineers back it up.

We cannot hope to reuse everything of our waste however. Sometimes trash is trash. There’s nothing else to do but get him out of the house. This brings up another big set of issues that need to be addressed. Indeed, one of the biggest challenges when it comes to creating a galactic waste system is the fact that we want to address what scientists call “planetary protection”, or the practice of keeping our dirty materials of terrestrial origin to contaminate celestial bodies such as planets or moons.

So, of course, we could bury the extraterrestrial waste, but that could lead to contamination. For example, if an astronaut throws trash in an ancient Martian crater, microbes created by the trash could grow, which could lead to a situation where we are misled into thinking we have discovered life when we don’t. found our own crappy microbes.

“You want to make sure your footprint is low,” Sepka explained. “We are looking for life forms. You want to make sure you haven’t polluted it and are only looking at your own signal.

It certainly doesn’t help that we’re already destroying places like Mars and the moon. Last spring, NASA released a photo of the rear hull of the Perseverance rover. Later that summer, the agency released a photo of a thermal blanket they discovered embedded in Martian rock.

In fact, we’ve dumped about 15,694 pounds of trash on Mars over the past 50 years of exploration. only. And even that is miniscule compared to the 400,000 pounds of trash, including materials, rovers, rocket boosters and assorted national flags we left behind on the moon. Imagine how much more it would be once we start colonizing the red planet or lunar surface.

A 2020 model published in Scientific reports says we need 110 people to properly colonize Mars, while Elon Musk hopes we’ll get 1 million people there. At either of those extremes, we’re still talking about exponentially more waste than there is right now. That’s why we need to start thinking about the best way to get rid of them now, rather than later when we get to these planets.

To that end, it seems like NASA is a bit slow to come up with a good system. Despite its many delays, the Artemis missions to return to the Moon are going well. This means that we could realistically begin to colonize the lunar surface within the next decade. In some decades, we will also have set foot on Mars.

According to Sepka, this means that the agency will not only have to develop a waste system for our arrival, but we also have to manage the waste in the spacecraft to make it happen.

Perseverance’s rear hull sits on the surface of Jezero Crater. Humans have generated nearly 16,000 pounds of trash on Mars in the past 50 years alone.


“The first thing to look at is in transit because that’s a whole different thing to being on a planet,” he explained. “That’s what we’re looking at now: being able to get people there and all the issues of accumulating trash on a spacecraft. What do you do with this?”

This is why waste compaction is so important. The smaller you can make it, the easier you can save space on board a capsule. If it gets too full, Sepka said, crew planners aren’t ruling out just tossing it into the cosmos, though he admits that wouldn’t be the ideal solution.

“It’s not popular,” he said. Mission designers don’t want to nurture the perception that humanity treats the solar system as its own personal dump. Sustainable waste management would not only help crews thrive in a resourceless environment like Mars, but it would also advance the moral imperative to protect other worlds from the environmental destruction and anthropogenic climate change that has is wreaking havoc on Earth. Hell, we literally have plastic in our blood because of it.

So when we go to a new planet, it only makes sense that we want to start off on the right foot. It means doing all the things we haven’t done on Earth and starting to recycle – one alien junk at a time.