Space health shocker: Astronauts return mostly fine

Largest ever study reveals some of the effects on human body aren't as bad as thought, but work needs to be done

Scientists have dumped a mountainous cache of research papers on the unsuspecting public in what amounts to the largest collective study of the effects of space travel on human health.

For the most part, the studies – which range from examination of blood, immune system, cardiovascular system, neurons, dehydration, kidneys, liver, skin, reproductive system and more – paint a picture that space flight is a fairly safe activity. Most biological shifts quickly return to baseline levels on Earth, although it's important to point out that a few do not.

"It's really mostly good news, in the sense that there are many, many changes across all those layers of biology and… biochemistry, but the vast majority of them return to baseline quickly and among the crew that is not [made up of] Olympic athletes who trained for 10 years to go to space," said Christopher Mason, professor of physiology and biophysics at Weill Cornell Medicine.

He led a study relying on data from SpaceX Inspiration4 mission, which launched with a civilian crew in 2021. They found the three-day spaceflight induced a broad range of physiological and stress responses, changes in balance systems and altered neurocognitive functioning, "almost all of which did not differ from (pre-flight) baseline after return to Earth."

Among the 26 papers published in Nature journals, one measured changes in telomeres, the specific DNA–protein structures found at both ends of each chromosome that shorten with age. Smoking, the absence of physical exercise, obesity, and stress all seem to shorten their length.

Susan Bailey, professor of environmental and radiological health sciences at Colorado State University, led the research.

She said: "What we observed was quite the opposite of what we imagined… that during spaceflight, both during the one year mission, as well as a cohort of other astronauts, we saw telomere actually lengthened during spaceflight. It was really a very surprising finding and we've been trying to figure out if that's a consistent finding."

Across the studies, there were opportunities to analyze countermeasures to the impacts of space travel on human health, the researchers said.

For telomeres, changes that are likely caused by radiation, researchers were "thinking about developing radiation protectors which would also have anti-ageing types of properties," Bailey said.

"These things are very important for not only thinking ahead for astronauts on long-duration missions, but also for life on Earth where we're also concerned about those things here too. So, there's some real opportunity, as we learn more about what's actually causing the really dramatic shifts in telomere length we're seeing during spaceflight and after that, that we'll be able to develop much more intelligently some of these mitigators that will help survival."

The research also uncovered skin problems occurring during space flight and the preliminary finding, pending further data, that women may return to biological baseline faster than men.

The paper summarizing the Space Omics and Medical Atlas (SOMA), which will be publicly available, said: "Leveraging the datasets, tools, and resources in SOMA can help accelerate precision aerospace medicine, bringing needed health monitoring, risk mitigation, and countermeasures data for upcoming lunar, Mars, and exploration-class missions." ®

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