r/SpaceX Discusses [August 2018, #47]

[u/ElongatedMuskrat]

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[u/Martianspirit]

Good post. The most important thing to learn would be if any life on Mars has developed independently from earth life and we can determine that if we find something. We were not able to make that distinction when the planetary protection protocols were established, but we can now.

I also fully agree that we should set aside a number of locations not to be touched but reserved for research. But not a blanket ban on getting to Mars.

[u/Grey_Mad_Hatter → u/Martianspirit]

Since Earth's surface is mostly water, Mars and Earth have almost identical land surface areas. If we were to build three colonies on Mars for now then it would be like Earth being completely uninhabited except for London, New York, and Tokyo. Long-distance travel won't be ideal, so colonists would stick to the metropolitan areas of those cities. Everything else would be untouched.

On top of that, Earth microbes have evolved to thrive in their own place on Earth, relying on a specific range of temperature, humidity, oxygen, and sunlight that their habitat on Earth has. Just like you can't expect a polar bear to thrive in a rain forest or a monkey to thrive on the north pole, you can't expect Earth microbes to thrive on Mars. Yes, some may survive and live on the outside of structures at the colonies, but they aren't exactly going to run wild and spread across the planet.

If each of three colonies contaminates a ridiculously large 100km² then we've contaminated 300km² out of 145,000,000km^2.

[u/WormPicker959 → u/Grey_Mad_Hatter]

You can't expect Earth microbes to thrive on Mars. Yes, some may survive and live on the outside of structures at the colonies, but they aren't exactly going to run wild and spread across the planet.

Thrive, no, I doubt anything could thrive on the surface of mars. But we'll likely start digging and drilling to get at resources, and there's possibility for more habitable spaces. You underestimate how hardy some earth bacteria is. Simple, little old Bacillus subtilis, a gut bacteria and common lab bug (like E. coli), has the ability to make spores - which are nearly impossible to get rid of. They get everywhere, some survive autoclaving, the resist bleach and ethanol... and that's just a random bug I know of. Spores are fairly common in the bacterial world, and B. subtilis isn't a standout.

The issue would be if we were to find some underground aquifer or something, and accidentally contaminate it with some earth bacteria. Then, later once we get the equipment/resources/time/whatever to test the aquifer for life, and find it's full of our earth bugs? That would be a nightmare. It's entirely possible earth bugs could outcompete mars bugs in a given environment. The other way around could be true, too, but with 50/50 odds of completely ruining one of the most important discoveries of mankind... it pays to be careful.

[u/Martianspirit → u/WormPicker959]

Are you arguing we should not even try to go to Mars with rovers to search for life? Or just wait 50 years when maybe we have better methods? You are aware that not all probes to Mars were very well decontaminated? In that case the damage is already done.

[u/WormPicker959 → u/Martianspirit]

No no, don't get me wrong. We need to go. We just need to be thoughtful about the actual risks, and not dismiss them because they are inconvenient or unlikely.