I think before you ask a question like this, you should estimate the likelihood of something like this happening or ask someone for help on how to do that.
These sorts of questions are so boring, so easy to ask, and instantly derail the discussion.
Of course its low, but its still something that needs to be considered as more and more commercial organizations gain the ability to launch things into our solar system. Obviously an organization like SpaceX has a commercial focus rather than a scientific one like NASA. The more stuff gets launched by more people the more likely of contamination from something.
Between SpaceX, Blue Origin or any other space travel initiatives that end up succeeding we are going to end up with a lot more stuff in space which isn't necessarily going to be friendly to scientific efforts as in the past.
None of what you said conflicts with my comment and suggested question re-formulation.
The world is filled with an unlimited number of concerns about infinitesimal risk. Your question remains boring and distracting, and, as pointed out elsewhere, the risk is not likely enough to be important.
And yet, it is a very important question that people will always ask first. Exactly how low are the probabilities? This was a major concern with the bankruptcy of Iridium that concerned the President. The insurers at the time wouldn't touch it. And bad things happen:
That's true. My point was that interplanetary contamination is a concern that needs to be addressed, even if the probabilities are low. If nothing else, since it is one of the first questions that is going to get asked, including by the USG.
This is why I suggest that the question should be "what are the chances of a collision?" not "what has SpaceX done to mitigate this?" since the former question admits that the asker does not have the background to assess anything, while the later suggests SpaceX has done something wrong if they haven't taken concrete actions.
As it turns out, the difference in probability between the things you mention and interplanetary collisions is astronomical -- like dozens or more orders of magnitude -- and a minute of Googling shows that NASA frequently satisfies the planetary protection rules by ensuring that non-sanitized parts of inbound spacecraft miss the planet on the first pass (even though they will in principle be circling in the same general orbit for a billion years).
I realize deep space collision risk is very low. I saw a talk with Alan Stern about New Horizons where he answers someone's question about collision avoidance in the asteroid belt that on a trip out to Pluto you are unlikely to encounter anything larger than a grain of sand. But rather than acting annoyed with the person who questioned him, he answered the question well, and I still remember his answer. And let use not forget that space exploration has ethically questionable choices and "improbable" events occur in the past (e.g., Laika, artificial radiation belts from nukes, debris from an RF reflecting foil cloud).
I don't understand. The question you link to is about orbit stability, not the risk of collision and planetary protection. The risk of collision is infinitesimal regardless.
But in any case, I'm happy with with earnest questions about math/science. What's boring and distracting are these expressions of concern about rule violations. Consider: would the original comment of NathanKP have been popular if he asked "I wonder what the chances are that the Tesla will collide with an asteroid?" No. Maybe someone would have quickly pointed to a calculation or estimate, but it would't be at the top of the thread without the emotional appeal that someone somewhere might be breaking a rule.
These sorts of questions are so boring, so easy to ask, and instantly derail the discussion.