'"Even if they radiated the outside, the engine would be dirty," says Melosh.'
Doesn't he know that the 'engine' is an electric motor, and no more dirty than a wheel bearing or any other moving part?

Well done Niio, that was going to be my first comment. Second is the authors reference to the drive train, it's not like a gearbox, prop shaft and differential of a conventional car. The motor output rotates the outer portion of the differential, that's it, it is all sealed. Also does the author know for certain that the car wasn't 'cleaned' before it was sent aloft?

Great. the majority of the skinflakes, hair and DNA in the car are Elon Musks. One day we may may meet aliens from planet X where the car payload crashed and started a new lifeform. The aliens will all be super bright descendents of Musk, each with a two or three major technology companies redesigning the universe and space travel. Worse, they may all look like Elon Musk babies.

Nice fearmonger article was written by a possible insomniac.

Do the people think they ever disinfected the Apollo or space shuttle missions before they launched them.

It is hard for most of us to comprehend bio-contamination. I use the analogy that its like everything is covered in wet paint. Touch it and its on you. Touch something else and it is also spread to that object. Now consider that the paint can reproduce and grow even more wet paint.

Space is big enough to accommodate all the microbes we can throw at it.

Although this article may be true, the context is just plain stupid. Elon and SpaceX plan to DELIBERATELY contaminate Mars with life from Earth and at a massive scale with colonization. Whether a few microbes get there ahead of humanity is irrelevant.

This is a rather ridiculous study ignoring that big meteorites having impacted on Earth have ejected bacteria over billions years spreading life-loaded rocks at least in the inner solar system. We know of many Moon and Mars meteorites having landed on Earth, and obviously the reverse should after Earth received asteroids.

The longest test of microbes exposed directly to the vacuum, temperature, and radiation of space was done in an experiment mounted on the exterior of International Space Station ("Expose" on the EuTEF platform) and lasted 18 months. Surprisingly, "some—but not all—of those most robust microbial communities from extremely hostile regions on Earth are also partially resistant to the even more hostile environment of outer space". A percentage of some of the test samples were revived successfully after the experiment. The test samples were rock lichen (fungi) specifically picked because they live in extremely cold, harsh environments on earth. How long they can ultimately last was not determined. Could they survive for millions of years riding an asteroid or a Tesla? It seems unlikely, but no one knows. Is the bacteria on Musk's Tesla a "a biothreat, or a backup copy of life on Earth"? If it isn't rock lichen and doesn't land on anything remotely hospitable for millions of years, probably not.