[AntiGuv]

NASA has both a Planetary Quarantine Program and a Sample Return Protocol depending on what they decide best fits the circumstances, but I don't know the details.

[ordinaryguy]

They do have sterilization procedures. Those procedures have been found to be lacking. When we send craft, we are also sending microbes. And that was true even when we really tried complete sterilization, which we don't bother with anymore.