Whoda thunk it? Humans living in space turns out to be more difficult and complex than we'd anticipate, and for surprising reasons. Specifically, humans living

Whoda thunk it? Humans living in space turns out to be more difficult and complex than we'd anticipate, and for surprising reasons. Specifically, humans living in microgravity. How about Mars (~1/3G) gravity or the Moon (~1/6G)? I suspect we're going to learn that it's a lot more complicated than we think. We've learned (and are still learning more) about the effects of medium-term microgravity on the human body, thanks to 20 years of guinea pig humans living aboard the ISS. But we know next to nothing about the conditions in between "zero"-G and full Earth gravity. And we know nothing at all about the long-term (decadal/lifelong) effects of (say) 0.3G. We have some notions that we might simulate gravity in a space-station by whirling things round and round, but will that be adequately similar to 'proper' gravity? Or will it turn out to be a hopelessly inadequate mockery for reasons we're quite unable to foresee? For example, the rather-more-substantial difference between the forces of 'gravity' experienced by our head vs our lower limbs... i.e. Our circulatory system evolved in conditions where that difference in force exerted by gravity between our feet and our heads is insignificant to the point of vanishment. But our bodies may not like so much a situation where there is a significant/quantifiable difference, resulting in pressure differentials in the various regions of the body that we were never evolved to experience. Not to mention associated coriolis forces... So I've long suspected that living in space (or on Mars or the Moon) might turn out a wee bit more complex than we anticipate.