We are only 3.7 billion years too late to be worrying about this. Earth rocks containing viable microbes have been landing on Mars for billions of years. I can't find a reference, but my memory is the rate is around 100 kg per year.<p>Edit. Found some references [1 - 3].<p>1. <a href="http://www.ncbi.nlm.nih.gov/pubmed/11543506" rel="nofollow">http://www.ncbi.nlm.nih.gov/pubmed/11543506</a><p>2. <a href="https://arxiv.org/pdf/1011.0101.pdf" rel="nofollow">https://arxiv.org/pdf/1011.0101.pdf</a><p>3. <a href="https://arxiv.org/pdf/0809.0378.pdf" rel="nofollow">https://arxiv.org/pdf/0809.0378.pdf</a>
> Her official title is US planetary protection officer<p>It's amusing that "US" has made it into her title, but it's pretty cool that there's a Prime Directive office.
Hosing the Martian biosphere as an invasive species seems inevitable so we may as well do it right and plan the thing out.<p>Rule 1: No single-point-of-failure (e.g. every alien in <i>Independence Day, War of the Worlds, Star Wars: The Phantom Menace, Mars Attacks</i>, etc.).<p>Rule 2: <i>Bio-Dome</i> was a cautionary tale.
Being careful is expensive, and as of this moment the people who are going to be landing on Mars first want to make a profit. Considering how we treat life that we're absolutely sure exists, and is a lot more complicated and near to us than alien microbes, I have no doubt at all how this will play out.<p>Lets just hope that Mars is sterile when we get there.
I don't see why we're obliged to care about the sanctity of Martian life. It's not an ethical question, because it doesn't involve harming any sentient being: living species don't have any inherent right to exist. Species go extinct on Earth all the time, and we aren't obliged to resurrect them.<p>Making humans better off (through advancing science, off-world colonization or mining) is an absolute good, and it should always take precedence over the possible extinction of non-sentient species.