It seems pollution is not just a problem on planet Earth. During its most recent exploration of the Red Planet, NASA's Curiosity rover left behind debris and "space trash," according to Grist.
In the process of Mars, the Curiosity not only left imprints all over the surface, but also left behind structural pieces that flew off the rover upon its arrival. Some 165-pound blocks of tungsten created craters three to five meters deep in the planet's previously unspoiled surface.
From its initial landing, the Rover began its complicated handling of the Red Planet. According to io9, all manner of damage was done when the rover's sky crane crashed into Mars' surface. Pieces of the sky crane flew off Curiosity and scattered over the planet, leaving debris and imprints.
The rover also left behind particles of its heatshield, descent parachute and backshell in the wake of Mars' dust storm.