NASA’s SpaceX Crew-7 crew members (pictured) spent 199 days in space. Credit score: NASA/Joel Kowsky
Solely about 600 individuals have ever traveled to space. The vast majority of astronauts over the previous six a long time have been middle-aged males on short-duration missions of fewer than 20 days.
At present, with personal, business and multinational spaceflight suppliers and flyers coming into the market, we’re witnessing a brand new period of human spaceflight. Missions have ranged from minutes, hours and days to months.
As humanity appears forward to returning to the Moon over the approaching decade, space exploration missions will likely be for much longer, with many extra space vacationers and even space vacationers. This additionally implies that a wider range of individuals will expertise the acute surroundings of space – extra ladies and other people of various ethnicities, ages and well being standing.
Since individuals reply otherwise to the distinctive stressors and exposures of space, researchers in space well being, like me, search to higher perceive the human well being results of spaceflight. With such data, we are able to work out easy methods to assist astronauts keep wholesome each whereas they’re in space and as soon as they return to Earth.
As a part of the historic NASA Twins Study, in 2019, my colleagues and I printed groundbreaking analysis on how one yr on board the Worldwide Area Station impacts the human physique.
I’m a radiation cancer biologist in Colorado State College’s Division of Environmental and Radiological Well being Sciences. I’ve spent the previous few years persevering with to construct on that earlier analysis in a sequence of papers just lately published across the portfolio of Nature journals.
These papers are a part of the Space Omics and Medical Atlas package of manuscripts, information, protocols and repositories that characterize the biggest assortment ever assembled for aerospace medication and space biology. Over 100 establishments from 25 international locations contributed to the coordinated launch of a variety of spaceflight information.
The NASA Twins Examine
NASA’s Twins Study seized on a singular analysis alternative.
NASA chosen astronaut Scott Kelly for the company’s first one-year mission, throughout which he spent a yr on board the Worldwide Area Station from 2015 into 2016. Over the identical time interval, his an identical twin brother, Mark Kelly, a former astronaut and present U.S. senator representing Arizona, remained on Earth.
My team and I examined blood samples collected from the dual in space and his genetically matched twin again on Earth earlier than, throughout and after spaceflight. We discovered that Scott’s telomeres – the protective caps on the ends of chromosomes, very similar to the plastic tip that retains a shoelace from fraying – lengthened, fairly unexpectedly, throughout his yr in space.
When Scott returned to Earth, nonetheless, his telomeres shortly shortened. Over the next months, his telomeres recovered however had been nonetheless shorter after his journey than that they had been earlier than he went to space.
As you grow old, your telomeres shorten due to quite a lot of components, together with stress. The size of your telomeres can serve as a biological indicator of your danger for creating age-related situations reminiscent of dementia, heart problems and most cancers.
In a separate study, my crew studied a cohort of 10 astronauts on six-month missions on board the Worldwide Area Station. We additionally had a management group of age- and sex-matched contributors who stayed on the bottom.
We measured telomere size earlier than, throughout and after spaceflight and once more discovered that telomeres had been longer throughout spaceflight after which shortened upon return to Earth. Total, the astronauts had many extra brief telomeres after spaceflight than that they had earlier than.
One of many different Twins Examine investigators, Christopher Mason, and I conducted another telomere study – this time with twin high-altitude mountain climbers – a considerably comparable excessive surroundings on Earth.
We discovered that whereas climbing Mount Everest, the climbers’ telomeres had been longer, and after they descended, their telomeres shortened. Their twins who remained at low altitude didn’t expertise the identical modifications in telomere size. These outcomes point out that it’s not the space station’s microgravity that led to the telomere size modifications we noticed within the astronauts – different culprits, reminiscent of increased radiation exposure, are extra possible.
Civilians in space
In our latest study, we studied telomeres from the crew on board SpaceX’s 2021 Inspiration4 mission. This mission had the primary all-civilian crew, whose ages spanned 4 a long time. The entire crew members’ telomeres lengthened through the mission, and three of the 4 astronauts additionally exhibited telomere shortening as soon as they had been again on Earth.
What’s significantly fascinating about these findings is that the Inspiration4 mission lasted solely three days. So, not solely do scientists now have constant and reproducible information on telomeres’ response to spaceflight, however we additionally understand it occurs shortly. These outcomes recommend that even brief journeys, like a weekend getaway to space, will likely be related to modifications in telomere size.
Scientists nonetheless don’t completely perceive the well being impacts of such modifications in telomere size. We’ll want extra analysis to determine how each lengthy and brief telomeres may have an effect on an astronaut’s long-term well being.
Telomeric RNA
In another paper, we confirmed that the Inspiration4 crew – in addition to Scott Kelly and the high-altitude mountain climbers – exhibited elevated ranges of telomeric RNA, termed TERRA.
Telomeres include numerous repetitive DNA sequences. These are transcribed into TERRA, which contributes to telomere construction and helps them do their job.
Along with laboratory research, these findings inform us that telomeres are being broken throughout spaceflight. Whereas there’s nonetheless rather a lot we don’t know, we do know that telomeres are particularly delicate to oxidative stress. So, the power oxidative harm that astronauts expertise when uncovered to space radiation across the clock possible contributes to the telomeric responses we observe.
We additionally wrote a review article with a more futuristic perspective of how higher understanding telomeres and growing older may start to tell the flexibility of people to not solely survive long-duration space journey but additionally to thrive and even colonize different planets. Doing so would require people to breed in space and future generations to develop up in space. We don’t know if that’s even doable – but.
Plant telomeres in space
My colleagues and I contributed different work to the Area Omics and Medical Atlas bundle, as properly, together with a paper published in Nature Communications. The examine crew, led by Texas A&M biologist Dorothy Shippen and Ohio College biologist Sarah Wyatt, discovered that, not like individuals, vegetation flown in space didn’t have longer telomeres throughout their time on board the Worldwide Area Station.
The vegetation did, nonetheless, ramp up their production of telomerase, the enzyme that helps keep telomere size.
As anybody who’s seen “The Martian” is aware of, vegetation will play a vital position in long-term human survival in space. This discovering means that vegetation are maybe extra naturally suited to face up to the stressors of space than people.
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