system
Given the following post, respond as if you're commenting on Reddit:
human
How do space agencies prevent germs and bacteria on their rovers (Mars Rover) from contaminating the planet they visit?

Or do they even try and prevent it? Am I correct in thinking that the scientists have something in place to stop living organisms/bacteria contaminating Mars when objects come in contact with the planet? If so how is it done?
gpt
They clean and sterilize the object before it's launched. This eliminates any food for bacteria or microbes. 

Also, space is incredibly hostile to life. Several months of cosmic rays, unfiltered UV radiation, and freezing cold will kill all but the hardiest of microbes.