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Quora: What Are the Potential Health Risks on Mars?

SpaceX Mars
Artist impression of Mars colonists arriving at the Red Planet. SpaceX

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Answer from Nicolas Nelson:

There are unhealthy ways to live on every continent, in every climate or city, even here on Earth. Mars has far greater challenges, but because of that, we will not go there cavalierly. No one is going to land on Mars, pop the hatch, leap out onto the planitia in shirtsleeves, and say "Hmm, wonder if I could live here?"

So, since you are concerned about "long-term health implications" and even wonder whether humans might live longer on Mars than we do on Earth, I'll assume that you assume we are talking about a well-planned, well-established human settlement on Mars. All the obvious threats like 1% Earth-normal atmospheric pressure, radiation exposure, perchlorates and peroxides in the soil, etc. have all been solved wisely somehow.

Because of this, the "long-term health repercussions" will mostly be marginal risks: still a higher lifetime radiation dose than on Earth, for example, and a higher risk of catastrophic death if there's the equivalent of a bus accident or a residential fire (though there will probably be a lower per-capita incidence of those things, precisely because the results could be so disastrous).

The real wild card for long-term health is the low gravity. Others have discussed microgravity's effects on the human body, but Mars is not free-fall. We really have no data at all for "partial-gravity" effects on the human body, except for the rudimentary data we got during the Apollo missions that put humans on the Moon (a 16% Earth-normal gravity environment). And that data is all very short term, not long enough to really see how the human body might acclimate over time, much less the effect that months and years might have.

Obviously, some bone-density and muscle-density loss is to be expected, but not as much as you might think. NASA seems to have solved much of those issues in the years of research conducted on the ISS, using a combination of exercise and medication. Similar drugs plus a Crossfit-style workout regimen would probably give you a Martian athlete who would do well on any visit to Earth. But most folks even on Earth aren't too excited about such exercise, so we have to assume that a sedentary life will be even more of a health hazard on Mars than on Earth.

Low gravity may have other negative effects too. Probably a higher rate of complications in pregnancy and early childhood physical development, although we really have no idea about that either, come to think of it. People just throw it out there as a proven hazard, and it simply isn't yet. Probable, yes. Avoidable? Surprisingly unfounded? We don't know yet.

Low gravity is equally probable to extend the lifespan of elderly humans on Mars, especially those born and bred on Earth. Probable? Yes. Guaranteed and proven? Certainly not!

We'll just need to go there and find out.

Is it unhealthy to live on Mars? originally appeared on Quora - the place to gain and share knowledge, empowering people to learn from others and better understand the world. You can follow Quora on Twitter, Facebook, and Google+. More questions:

Quora: What Are the Potential Health Risks on Mars? | Opinion