Solely about 600 folks have ever traveled to area. The overwhelming 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, industrial 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, area exploration missions will likely be for much longer, with many more room vacationers and even area vacationers. This additionally implies that a wider range of individuals will expertise the intense atmosphere of area – extra ladies and folks of various ethnicities, ages and well being standing.
Since folks reply in a different way to the distinctive stressors and exposures of area, researchers in area well being, like me, search to higher perceive the human well being results of spaceflight. With such info, we are able to work out tips on how to 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 Research, 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 most cancers 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 collection of papers just lately printed throughout the portfolio of Nature journals.
These papers are a part of the Area Omics and Medical Atlas package deal of manuscripts, information, protocols and repositories that signify 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 information.
The NASA Twins Research
NASA’s Twins Research seized on a novel 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 similar twin brother, Mark Kelly, a former astronaut and present U.S. senator representing Arizona, remained on Earth.
NASA astronaut Scott Kelly, left, who went into area through the NASA Twins Research, stands subsequent to his twin brother, Mark Kelly, who stayed on Earth.
AP Picture/Pat Sullivan
My group 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 protecting 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, nevertheless, 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 become older, your telomeres shorten due to quite a lot of elements, together with stress. The size of your telomeres can function a organic indicator of your danger for growing age-related situations corresponding to dementia, heart problems and most cancers.
In a separate examine, my group 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. General, 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 performed one other telomere examine – this time with twin high-altitude mountain climbers – a considerably related excessive atmosphere 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 area station’s microgravity that led to the telomere size modifications we noticed within the astronauts – different culprits, corresponding to elevated radiation publicity, are extra seemingly.
Civilians in area
In our newest examine, 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. All the 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.
The crew members from SpaceX’s 2021 Inspiration4 mission.
SpaceX, CC BY-NC
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 area, 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 one other 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 so much we don’t know, we do know that telomeres are particularly delicate to oxidative stress. So, the persistent oxidative injury that astronauts expertise when uncovered to area radiation across the clock seemingly contributes to the telomeric responses we observe.
We additionally wrote a evaluation article with a extra futuristic perspective of how higher understanding telomeres and getting older may start to tell the flexibility 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 Area Omics and Medical Atlas package deal, as nicely, together with a paper printed in Nature Communications. The examine group, led by Texas A&M biologist Dorothy Shippen and Ohio College biologist Sarah Wyatt, discovered that, in contrast to folks, crops flown in area didn’t have longer telomeres throughout their time on board the Worldwide Area Station.
The crops did, nevertheless, ramp up their manufacturing of telomerase, the enzyme that helps preserve telomere size.
As anybody who’s seen “The Martian” is aware of, crops will play a necessary 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.