Space changes you, even on short trips off-planet.
Four people who spent three days off Earth in September 2021 experienced physical and mental changes that included slight declines in cognitive tests, stressed immune systems and genetic changes within their cells, scientists report in a set of articles published Tuesday in the journal Nature and several other related journals.
Almost everything that changed about the astronauts returned to normal after they landed on Earth. None of the changes appear to be major precautions for future space travelers. But the results also highlighted how little medical researchers know.
Christopher Mason, professor of genomics, physiology and biophysics at Weill Cornell Medicine in New York and one of the leaders of the research, called the collection of papers and data “the most thorough examination we have never had on a crew.” » as he said during a press conference on Monday.
The four astronauts carried out a mission, known as Inspiration4, which was the first trip to orbit where none of the crew members were professional astronauts. Jared Isaacman, a billionaire entrepreneur, led the mission. Instead of bringing friends, he recruited three travelers who represented a broader section of society: Hayley Arceneaux, a physician’s assistant who survived childhood cancer; Sian Proctor, a community college professor who teaches geosciences; and Christopher Sembroski, engineer.
Inspiration4 crew members agreed to participate in medical experiments – collecting samples of blood, urine, feces and saliva during their flight – and to allow the data to be cataloged in an archive online known as Space Omics and Medical Atlas, or SOMA, which is publicly available.
Although the data is anonymous, this doesn’t offer much privacy as there were only four crew members on Inspiration4. “Actually, you could probably figure out who’s who,” Dr. Proctor said in an interview.
But she added: “I just think there’s more good than harm in being able to share my information and allow science to progress and learn.” »
SOMA also includes data from others who have participated in private space missions, as well as from Japanese astronauts who have flown to the International Space Station, as well as a study comparing the health of Scott Kelly, a NASA astronaut who lived on the International Space Station. for 340 days in 2015 and 2016, with his twin brother, Mark, a retired astronaut who is now a senator representing Arizona.
As more individuals purchase trips to space, it is hoped that SOMA will quickly provide more information about a wider range of people than the older white men who were selected to become astronauts in the early decades of the space age. This could lead to treatments tailored to each astronaut to combat the effects of spaceflight.
The wealth of information also allowed scientists to compare short-term effects with what happens during longer missions.
During Mr. Kelly’s year in space, age markers in his DNA, called telomeres, lengthened, suggesting, surprisingly, that he had become biologically younger. But telomeres mostly returned to their previous size after he returned to Earth, although some became even shorter than before he left. Scientists interpreted this as a sign of accelerated aging.
The telomeres of the four Inspiration4 astronauts also lengthened and then shortened, indicating that the changes are occurring in all astronauts and that they are occurring quickly.
“A remarkable finding in many ways,” said Susan Bailey, a professor of radiation cancer biology and oncology at Colorado State University who led the telomere research.
Cells use RNA, a single-stranded chain of nucleic acids that translates the blueprints coded in DNA into the production of proteins. Dr Bailey said the RNA corresponding to telomeres had also changed in astronauts and similar changes had been seen in people climbing Mount Everest.
“Which is a strange connection,” she said.
This suggests that the cause of telomere growth and shrinkage is not weightlessness but rather the bombardment of radiation that humans experience at high altitudes and in space.
This is not the only effect of spaceflight.
Afshin Beheshti of the Blue Marble Space Institute of Science and NASA Ames Research Center in California pointed to molecular changes in astronauts’ kidneys that could portend the formation of kidney stones. This wouldn’t be a problem on a three-day space trip, but could become a medical crisis on a longer mission.
“Halfway to Mars, how are you going to deal with this?” » said Dr. Beheshti.
But now that this possibility is known, researchers could study how to prevent kidney stones or develop better methods to treat them.
The astronauts took several tests on iPad to measure their cognitive performance in space. One test assessed what is called psychomotor alertness, a measure of the ability to focus on a task and maintain attention. The astronaut was looking at a box on the screen. A timer then suddenly appeared in the box, counting down the time until a button was pressed.
If the response was too slow, longer than 355 milliseconds, it was considered a lack of attention. On average, performance in space declined compared to when the Inspiration4 astronauts performed the same test on the ground. Other tests indicate deficits in visual search and working memory.
“Our cognitive performance was not affected spatially, but our response speed was slower,” Ms. Arcenaux said in an email. “That surprised me.”
But Dr Proctor said this may not be a real difference in their ability to perform tasks in space, just that they may be distracted. “It’s not because you don’t have the capacity to test better,” she said. “It’s just because you look up for a minute, and there’s Earth out the window, and you’re like, ‘Whoa.’
One benefit of collecting all the data is looking for connections between changes, something that was difficult for scientists to do with earlier, smaller data sets. “When you look at the whole thing, you start to see the pieces of the puzzle together,” Dr. Beheshti said.
That could indicate a common cause, “and then countermeasures would easily be easier to target,” he said.
Since their return to Earth, life for some of the Inspiration4 astronauts has returned, in many ways, to what it was before they went into space. Ms. Arcenaux returned to her 12-hour shift as a physician assistant at St. Jude Children’s Research Hospital in Memphis. Dr. Proctor is still a community college professor. Mr. Sembroski, who lives near Seattle, now works as an engineer at Blue Origin, the rocket company owned by Jeff Bezos.
But Dr. Proctor is now also a scientific envoy for the United States Department of State. This week she visits Peru and Chile, recounting her experiences in schools and universities. “I now also have this kind of global platform where I can go and do things like inspire and help prepare the next generation,” she said.
Arcenaux said she remembered looking down at Earth from the dome of the SpaceX Crew Dragon spacecraft on the second day of her trip.
“I feel so connected to my fellow earthlings,” she said. “We are one on this beautiful planet.”
As for Mr. Isaacman, he is not done with space. He and three other non-professional astronauts will embark on a mission called Polaris Dawn, which could launch next month. During this flight, still in a SpaceX Crew Dragon capsule, Mr. Isaacman and another crew member plan to attempt the first private spacewalk.