Source for that claim? The number of studies I’ve read (as well as conversations I’ve had with astronauts) about the health impact on astronauts who’ve been on the ISS for extended periods seems to disagree.
https://www.space.com/23017-weightlessness.html
https://science.nasa.gov/science-news/science-at-nasa/2001/a...
http://www.cnn.com/2016/05/20/health/your-body-in-space/inde...
https://www.nasa.gov/hrp/bodyinspace
https://en.wikipedia.org/wiki/Effect_of_spaceflight_on_the_h...
tl;dr version:
> In space, without gravity, bones lose more than 1% of minerals and density per month.
> Astronauts also experience blood volume loss, weakened immune systems and cardiovascular deconditioning since floating takes little effort and the heart doesn't have to work as hard to pump blood through your body
> "It changes their visual acuity," Charles said. "They're not able to see things up close. It's like advanced aging. That sort of thing happens at a sort of an accelerated rate."
https://www.space.com/5245-long-space-missions-risk-cancer-p...
https://srag.jsc.nasa.gov/SpaceRadiation/Why/Why.cfm
All of those links are on radiation in space. The first two are as it relates to accelerated aging. These were not difficult to find.
maybe we need to sacrifice our own moon.