Space changes you, even during short trips off-planet.
Four people who spent three days outside Earth in September 2021 experienced physical and mental changes, including a slight decrease in cognitive tests, a stressed immune system and genetic changes in their cells, scientists report in a package of papers published on Tuesday in the journal Nature and several other related journals.
Almost everything that changed in the astronauts returned to normal after they crashed on Earth. None of the changes seemed to be a warning to future space travelers. But the results also showed how little medical researchers know.
Christopher Mason, a professor of genomics, physiology and biophysics at Weill Cornell Medicine in New York City and one of the leaders of the study, called the paper and data collection “the most in-depth study we’ve ever had of a crew.” ‘, as he said during a press conference on Monday.
The four astronauts traveled on a mission known as Inspiration4, 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 swath of society: Hayley Arceneaux, a physician assistant who survived childhood cancer; Sian Proctor, a community college professor who teaches geosciences; and Christopher Sembroski, an engineer.
Inspiration4’s crew members agreed to participate in medical experiments – collecting blood, urine, feces and saliva samples during their flight – and to allow the data to be cataloged in an online archive known stands as the Space-omics and medical atlasor SOMA, which is publicly available.
Although the data is anonymized, it doesn’t offer much privacy since there were only four crew members on Inspiration4. “You could probably figure out who’s who,” Dr. Proctor said in an interview.
But she added, “I just feel like there’s more good than harm that comes from being able to share my information and advance science and learn.”
SOMA also includes data from other people who have flown on private space missions, as well as Japanese astronauts who have flown to the International Space Station, and a study that compared 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 citizens purchase trips to space, the hope is that SOMA will soon include more information about a broader range of people than the older white men who were selected to become astronauts in the early decades of the space age. That could lead to treatments tailored to individual astronauts 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 grew longer — suggesting, surprisingly, that he had become biologically younger. But the telomeres largely returned to their previous size after he returned to Earth, though some were even shorter than before he left. Scientists interpreted that as a sign of accelerated aging.
The telomeres of all four Inspiration4 astronauts also lengthened and then shortened, indicating that the changes are happening in all astronauts and that they are happening quickly.
“A remarkable finding in a number of ways,” said Susan Bailey, a professor of biology and radiation oncology at Colorado State University, who led the telomere study.
Cells use RNA, a single-stranded nucleic acid that translates blueprints encoded in DNA to produce proteins. Dr. Bailey said that RNA corresponding to telomeres had also changed in the astronauts and that similar changes had been observed in people who climbed Mount Everest.
“That’s a strange connection,” she said.
This suggests that the cause of the growing and shrinking telomeres is not weightlessness, but rather the bombardment of radiation that people experience at high altitudes and in space.
That wasn’t the only effect of spaceflight.
Afshin Beheshti of the Blue Marble Space Institute of Science and NASA’s Ames Research Center in California pointed to molecular changes in the astronauts’ kidneys that could predict the formation of kidney stones. That wouldn’t be a problem during a three-day space flight, but could become a medical crisis during a longer mission.
“Halfway to Mars, how are you going to treat that?” said dr. Beheshti.
But now that the possibility is known, researchers could study how to prevent kidney stones or develop better methods to treat them.
The astronauts performed various tests on iPads to measure their cognitive performance in space. One test evaluated what is known as psychomotor vigilance, a measure of the ability to focus on a task and maintain attention. The astronaut stared at a box on the screen. Then suddenly a stopwatch appeared in the box, counting the time until a button was pressed.
If the response was too slow, longer than 355 milliseconds, it was considered a loss of attention. On average, performance in space deteriorated compared to when the Inspiration4 astronauts did the same test on the ground. Other tests indicate deficits in visual search and working memory.
“Our cognitive performance was not affected in space, but our speed response was slower,” Ms. Arcenaux said in an email. “That surprised me.”
But Dr. Proctor said that this might not be a real difference in their ability to perform tasks in space, but rather that they might be distracted. “It’s not because you don’t have the ability to do better on the test,” she said. “It’s just because you look up for a moment, and there’s the Earth out the window, and you think, ‘Wow.'”
One of the benefits of collecting all the data is looking for connections between the changes, something that scientists found difficult to do with previous, more limited data sets. “When you look at it as a whole, you start to see the pieces of the puzzle together,” said Dr. Beheshti.
That could point to a common cause, “and then countermeasures are more easily targeted,” he said.
Since returning to Earth, life for some Inspiration4 astronauts has in many ways returned to what it was like before they went to space. Ms. Arcenaux is back working 12-hour shifts as a physician assistant at St. Jude Children’s Research Hospital in Memphis. Dr. Proctor is still a professor at a community college. Mr. Sembroski, who lives near Seattle, now works as an engineer at Blue Origin, Jeff Bezos’ rocket company.
But Dr. Proctor is also now a science envoy for the U.S. State Department. This week she’s visiting Peru and Chile, where she’ll talk about her experiences in schools and universities. “I also now have this kind of global platform where I can go and do things like inspire and help prepare the next generation,” she said.
Ms. Arcenaux said she remembered looking at Earth from the dome window 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 all one on this beautiful planet.”
As for Mr. Isaacman, he’s not done with space yet. He and three other nonprofessional astronauts are headed to a mission called Polaris Dawn, which could launch next month. During that flight, again in a SpaceX Crew Dragon capsule, Mr. Isaacman and another crew member plan to conduct the first private spacewalk.
