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Title: humans LEFT a Mess on Mars, Now Scientists Want to Catalog it Before it’s Too Late

In the annals of space exploration, no human has set foot on Mars. yet, we’ve already left our mark – and a lot of mess – on the Red Planet. Since 1971, when Mars 2, a spacecraft from the Soviet Union, crash-landed on Mars, we’ve been littering the planet with space debris.

Crash sites, parachutes, and rover tracks are just a few examples of the human-generated garbage scattered across Mars. And let’s not forget the hardy Earth bacteria that have hitched rides there unintentionally.

But while this might sound like a case of space pollution, a group of anthropologists led by Justin Holcomb, a researcher from Kansas University, sees it differently. They’re pushing NASA and other space agencies to create a catalog of all known objects on Mars before the planet’s harsh environment serves as acenterymaker (or grave) for these artifacts.

"It’s not just trash," Holcomb told Science Daily. "These things are actually really important. The solution for space junk is disposal, but the solution for heritage is preservation. There’s a big difference."

Space Debris: More Than Just Litter

Usually, when scientists discuss space debris, they’re referring to the large amounts of orbital clutter that threatens Earth-based satellites and endangers astronauts at the International Space Station (ISS). The U.S. Department of Defense tracks about 27,000 objects larger than 10 cm in orbit around Earth, but many smaller pieces go undetected.

NASA estimates there are around 500,000 cesium-sized pieces – that’s about the size of a grain of salt – that aren’t tracked. It’s alarming because even a tiny speck of debris, like a high-speed screw, can cause serious damage to a spacecraft.

However, the idea of space debris as an archaeological record of human achievement isn’t a novel concept. In 2012, NASA published an inventory of about 800 items left or placed on the Moon. This catalog included astronaut poop, utensils, lunar quake experiments, hammers, vomit bags, orbiters, cameras, mirrors, golf balls, cosmic radiation detectors, shoes, dead spacecraft, and even a US$2 bill.

Mars’ Junkyard

The goal of the Moon catalog wasn’t to take responsibility for the mess, but to document and preserve the record of human activities there. And yes, Neil Armstrong and Buzz Aldrin’s poop are part of that historical record. Some even consider it a scientific resource.

Much has changed in the decades since the Moon catalog was published. Now, private companies are also sending spacecraft to the Moon, and sometimes crashing them. Nations once perceived as space rookies, like India, have joined the fray, leaving their own marks on the lunar surface.

Currently, there are no plans to update the Moon catalog, says Brian Odom, NASA’s chief historian. "That’s not a bad idea," Odom says. "But there’s nothing being done about it right now."

Meanwhile, Mars continues to accumulate human-generated clutter. Scientists are aware of the threat that Mars’ dust devils pose. About 12 years ago, NASA’s Mars Reconnaissance Orbiter witnessed an extraordinary dust devil stretching 19 km into the sky. Mars’ dust has blanketed the solar panels of the InSight lander, which stopped working in 2022, and has camouflaged the Ingenuity helicopter that crashed in January 2024.

Holcomb, whose team proposed a Mars catalog in a recent Nature Astronomy paper, is most concerned about sand dunes. "For instance, the Spirit rover is right next to an approaching sand dune that will eventually bury it," he says. Once buried, it will be difficult to unearth.

NASA’s Mars Exploration Program doesn’t have plans to inventory these objects, but doing so might not be as challenging as expected. "These artifacts are essentially like the stone tools in East Africa or Clovis points in America," Holcomb says. "They represent first contact, and from an archaeological perspective, they’re key points in our historical timeline of migration."

As humanity’s reach extends further into space, it’s clear we need a better system for managing our waste – from Earth to the Moon, and now to Mars. Because while we may not be physically present on these celestial bodies, our impact is undeniable. And maybe, just maybe, our litter can tell a story about our journey through the cosmos.

(rns/rns)