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March 13, 2026<\/p>\n
3 min read<\/p>\n
Add Us On Google<\/span>Add SciAm<\/span><\/span><\/p>\n 24 mice launched to orbit in 2023. What happened to their bodies could help humans better survive in space<\/p>\n The human body is not built for life in space, and a new study helps reveal how<\/p>\n By Jackie Flynn Mogensen edited by Claire Cameron<\/span><\/p>\n The International Space Station, as seen from the SpaceX Crew Dragon Endeavour spacecraft on November 8, 2021.<\/p>\n Humans did not evolve for space. Ironically, because we insist on going there anyway, scientists now know from studying astronauts that the lack of Earth\u2019s gravity can wreak health havoc, such as by shifting our soft, watery organs, throwing off gut bacteria, weakening our bones, and more.<\/p>\n None of that, however, seems to dampen the spirits of the astronauts who go to space. And understanding more about how gravity affects our health could help humans live better off Earth.<\/p>\n Now a first-of-its-kind study in mice that were sent to the International Space Station (ISS) suggests that living with different gravity causes changes to our muscles\u2014and it identifies a critical threshold when problems may start to set in.<\/p>\n If you’re enjoying this article, consider supporting our award-winning journalism by subscribing. By purchasing a subscription you are helping to ensure the future of impactful stories about the discoveries and ideas shaping our world today.<\/p>\n If you\u2019re reading this on Earth, you\u2019re experiencing about 1 g worth of gravity. On Mars, you\u2019d feel about 38 percent of Earth\u2019s gravity, or 0.38 g. The moon\u2019s gravity is even less, at just about 0.17 g, or a sixth of Earth\u2019s. But at what gravity does our body lose its regular function?<\/p>\n The study, published on Friday in the journal Science Advances, shows that mice in space that were kept at 0.67 g maintained most of their muscular function and muscle fiber composition. But when the mice lived in an environment below that gravity, their muscles started to change for the worse. The results could help keep humans healthy in space, including on possible future trips to explore other planets.<\/p>\n \u201cI think this provides some really interesting information about long-duration missions to Mars and beyond,\u201d says Mary Bouxsein, a co-author of the study and a professor of orthopedic surgery at Harvard Medical School, adding that it\u2019s somewhat reassuring that mice could maintain their muscular function without a full 1 g.<\/p>\n In 2023 an international group of researchers sponsored by NASA and the Japan Aerospace Exploration Agency (JAXA) launched 24 mice on a SpaceX Falcon 9 rocket for a visit to the ISS. There the mice were kept in one of four gravity levels\u2014microgravity, 0.33 g, 0.67 g and 1 g\u2014for around four weeks. When the mice returned to Earth, researchers on the ground analyzed their muscle tissue for signs of deterioration.<\/p>\n Specifically, the team looked at the leg\u2019s soleus muscle, which is known to be sensitive to gravity. At 0.33 g, the mice\u2019s muscle size was about the same as it was under full gravity, but the animals were weaker, as measured by their grip strength. At 0.67 g, however, the mice saw \u201cfull protection of muscle function,\u201d Bouxsein says, meaning that their grip was about the same as it was at 1 g.<\/p>\n The results clearly show the effect of different levels of gravity on muscle structure and function, says Se-Jin Lee, a geneticist at the University of Connecticut, who also studies the effect of spaceflight on health but was not involved in the new study.<\/p>\n \u201cA key question will be the extent to which these findings will translate to humans during space travel, specifically with respect to the threshold for seeing significant effects on muscle health in humans,\u201d he says.<\/p>\n To Lee\u2019s point, mice are obviously different from humans. We use our muscles differently\u2014mice scurry on four legs while humans evolved to walk on two\u2014and our muscle composition is different, too, Bouxsein says. But the paper provides an important starting point for future research on the health effects of spaceflight, such as studies of how different degrees of gravity affect other tissues and what effect exercise has on muscle loss.<\/p>\n The study also raises questions about whether it is possible to live on Mars, as SpaceX CEO and tech billionaire Elon Musk hopes humans might do one day. On the Red Planet, humans would be subject to gravity below the 0.67-g threshold.<\/p>\n \u201cIt does suggest that Mars gravity alone would not be enough to preserve muscle function,\u201d Bouxsein says. On the other hand, she notes, perhaps we won\u2019t need as much strength on a planet with less gravity anyway.<\/p>\n \u201cMaybe on the way back, when you\u2019re coming back to Earth, you need to build it up so that you\u2019re ready to go when you get back,\u201d she says.<\/p>\n If you enjoyed this article, I\u2019d like to ask for your support. Scientific American<\/span> has served as an advocate for science and industry for 180 years, and right now may be the most critical moment in that two-century history.<\/p>\n I\u2019ve been a Scientific American<\/span> subscriber since I was 12 years old, and it helped shape the way I look at the world. SciAm <\/span>always educates and delights me, and inspires a sense of awe for our vast, beautiful universe. I hope it does that for you, too.<\/p>\n If you subscribe to Scientific American<\/span>, you help ensure that our coverage is centered on meaningful research and discovery; that we have the resources to report on the decisions that threaten labs across the U.S.; and that we support both budding and working scientists at a time when the value of science itself too often goes unrecognized.<\/p>\n In return, you get essential news, captivating podcasts, brilliant infographics, can’t-miss newsletters, must-watch videos, challenging games, and the science world’s best writing and reporting. You can even gift someone a subscription.<\/p>\n There has never been a more important time for us to stand up and show why science matters. I hope you\u2019ll support us in that mission.<\/p>\n","protected":false},"excerpt":{"rendered":" March 13, 2026 3 min read Add Us On GoogleAdd SciAm 24 mice launched to orbit in 2023. What happened to their bodies could help humans better survive in space The human body is not built for life in space, and a new study helps reveal how By Jackie Flynn Mogensen edited by Claire Cameron<\/p>\n","protected":false},"author":1,"featured_media":46684,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[58],"tags":[2249,419,3698,10289,23357,10262,1101,2640],"class_list":{"0":"post-46683","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-science","8":"tag-bodies","9":"tag-happened","10":"tag-humans","11":"tag-launched","12":"tag-mice","13":"tag-orbit","14":"tag-space","15":"tag-survive"},"_links":{"self":[{"href":"https:\/\/naijaglobalnews.org\/index.php?rest_route=\/wp\/v2\/posts\/46683","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/naijaglobalnews.org\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/naijaglobalnews.org\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/naijaglobalnews.org\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/naijaglobalnews.org\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=46683"}],"version-history":[{"count":0,"href":"https:\/\/naijaglobalnews.org\/index.php?rest_route=\/wp\/v2\/posts\/46683\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/naijaglobalnews.org\/index.php?rest_route=\/wp\/v2\/media\/46684"}],"wp:attachment":[{"href":"https:\/\/naijaglobalnews.org\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=46683"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/naijaglobalnews.org\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=46683"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/naijaglobalnews.org\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=46683"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}On supporting science journalism<\/h2>\n
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