NASA’s SpaceX Crew-7 crew members (pictured) spent 199 days in area. Credit score: NASA/Joel Kowsky
Solely about 600 folks have ever traveled to area. The vast majority of astronauts over the previous six many years have been middle-aged males on short-duration missions of fewer than 20 days.
Right this moment, with non-public, business and multinational spaceflight suppliers and flyers getting 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 to be like forward to returning to the Moon over the approaching decade, area exploration missions will likely be for much longer, with many more room vacationers and even area vacationers. This additionally implies that a wider variety of individuals will expertise the intense surroundings of area – extra ladies and other people of various ethnicities, ages and well being standing.
Since folks reply in another way to the distinctive stressors and exposures of area, researchers in area well being, like me, search to raised perceive the human well being results of spaceflight. With such info, we are able to determine how one can assist astronauts keep wholesome each whereas they’re in area 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 House 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 lately published across the portfolio of Nature journals.
These papers are a part of the Space Omics and Medical Atlas package of manuscripts, knowledge, protocols and repositories that characterize the most important assortment ever assembled for aerospace medication and area biology. Over 100 establishments from 25 international locations contributed to the coordinated launch of a variety of spaceflight knowledge.
The NASA Twins Research
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 House Station from 2015 into 2016. Over the identical time interval, his equivalent 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 area 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 like the plastic tip that retains a shoelace from fraying – lengthened, fairly unexpectedly, throughout his yr in area.
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 area.
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 threat for creating age-related circumstances reminiscent of dementia, heart problems and most cancers.
In a separate study, my group studied a cohort of 10 astronauts on six-month missions on board the Worldwide House Station. We additionally had a management group of age- and sex-matched members 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 Research investigators, Christopher Mason, and I conducted another telomere study – this time with twin high-altitude mountain climbers – a considerably related 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 adjustments in telomere size. These outcomes point out that it’s not the area station’s microgravity that led to the telomere size adjustments we noticed within the astronauts – different culprits, reminiscent of elevated radiation publicity, are extra probably.
Civilians in area
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 many years. The entire crew members’ telomeres lengthened throughout the mission, and three of the 4 astronauts additionally exhibited telomere shortening as soon as they had been again on Earth.
What’s significantly attention-grabbing about these findings is that the Inspiration4 mission lasted solely three days. So, not solely do scientists now have constant and reproducible knowledge on telomeres’ response to spaceflight, however we additionally understand it occurs shortly. These outcomes counsel that even brief journeys, like a weekend getaway to area, will likely be related to adjustments in telomere size.
Scientists nonetheless don’t completely perceive the well being impacts of such adjustments 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 a number of 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 may be nonetheless quite a bit we don’t know, we do know that telomeres are particularly delicate to oxidative stress. So, the continual oxidative harm that astronauts expertise when uncovered to area radiation across the clock probably contributes to the telomeric responses we observe.
We additionally wrote a review article with a more futuristic perspective of how higher understanding telomeres and ageing may start to tell the power of people to not solely survive long-duration area journey but additionally to thrive and even colonize different planets. Doing so would require people to breed in area and future generations to develop up in area. We don’t know if that’s even attainable – but.
Plant telomeres in area
My colleagues and I contributed different work to the House Omics and Medical Atlas package deal, as properly, together with a paper published in Nature Communications. The examine group, led by Texas A&M biologist Dorothy Shippen and Ohio College biologist Sarah Wyatt, discovered that, not like folks, crops flown in area didn’t have longer telomeres throughout their time on board the Worldwide House Station.
The crops 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, crops will play an important position in long-term human survival in area. This discovering means that crops are maybe extra naturally suited to face up to the stressors of area than people.
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