The International Space Station is growing mould, inside and outside
"The research touches on this, and it warns astronauts to follow recommended planetary protection protocols designed to prevent visiting spacecraft from contaminating other planets and moons in our solar system with microorganisms from Earth. The study suggests that, because of the risk of contamination, these fungal spores may need to be considered a more serious threat."This makes me wonder if we've accidentally already started terraforming Mars.