Micro-G is known to be detrimental to health in the long-term. However, the Moon is at $\frac{1}{6}$ G (while Mars is at ~$\frac{3}{8}$ G). Is $\frac{1}{6}$ G enough for humans to remain healthy in the long term?

(While there are many concerns that make Moon colonization difficult -- i.e. long night/day cycles resulting in large temperature swings -- please focus on the gravity/health question for now.)

This question may be answered in the long term by the Space Studies Institute's "G-Lab" program.

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    $\begingroup$ Interesting question, I'm not sure if we actually know as we haven't had anyone living in low gravity for any length of time. $\endgroup$
    – GdD
    Sep 20, 2021 at 16:12
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    $\begingroup$ related: Does lower gravity on Mars make it unsafe and unhealthy for humans? $\endgroup$
    – Harabeck
    Sep 20, 2021 at 16:21
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    $\begingroup$ I have asked this myself for a while, maybe our bodies are much better able to cope in mini-gravity than in micro-gravity. I don't think there are many studies on this (how would there..) but let's see what others know.. $\endgroup$ Sep 20, 2021 at 21:40
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    $\begingroup$ Related but not necessarily a duplicate: Least artificial gravity needed to maintain health on a one year space trip? HopDavid's answer is "Finding minimum gravity to keep humans healthy should be a high priority....At this time it remains an open question. We really have only two data points: the weightlessness of someone in orbit and the full g on earth's surface" and it links to their blog post What is Minimum Spin Hab? As Uwe points out, the answer here is the same. $\endgroup$
    – uhoh
    Sep 21, 2021 at 1:05

1 Answer 1


We don't have enough medical data to decide if 0.1667 g is enough or too few. To get enough data we would need hundreds of humans living at 0.1667 g for some decades.

But from what we know now it would be unhealthy to return to 1 g after years at 0.1667 g.

We don't know if a lot of training would be sufficient to keep all bones of the body strong enough for the return to 1 g. What if all bones of the arms and legs got the density needed for 1 g, but some vertebrae are not dense enough?


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