Humans have already littered on Mars despite never visiting the Red Planet.
Humans have littered the surface of Mars
Space junk has piled up on the surface with debris from missions including landing equipment, heat shields and parachutes all left behind.
There is thought to be over 15,000 lbs of human trash on Mars from human spacecraft that have landed over the past half a century - including the lost British Beagle 2 spacecraft that touched down in 2003.
Dr. James Blake, a researcher of space debris at the University of Warwick, has argued that future human missions to Mars should be "designed with sustainability in mind".
He said: "There's still an unfortunate balance that needs to be struck between scientific discovery and the impact of missions on the natural environment of these remote worlds."
Dr. Blake proposes that missions to Mars could collect the space junk from the planet.
The scientist said: "It's likely that future colonies would go in search of these relics as historical artefacts.
"By that point, though, it's likely we'll be making a mess of the planet in other ways."