We’re about to learn a whole lot more about how the human body reacts to space 

We could be entering a renaissance for human spaceflight research, as a record number of private citizens head to space — and as scientists improve techniques for gathering data on these intrepid test subjects. 

A sign that the renaissance is imminent appeared earlier this week, when the journal Nature published a cache of papers detailing the physical and mental changes the four-person Inspiration4 crew experienced nearly three years ago. That mission, in partnership with SpaceX, launched on September 15, 2021 and returned to Earth three days later. 

During the mission, the crew experienced a broad set of modest molecular changes, dysregulated immune systems and slight decreases in cognitive performance. But researchers are only able to analyze the data — more than 100,000 health-related data points — because the four-person crew was able to reliably collect it in the first place. 

This is a bigger accomplishment than one might realize. The Inspiration4 crew received plenty of training, in large part with SpaceX, which provided the Dragon capsule for their ride through orbit. But their preparation is still a far cry from that of NASA astronauts aboard the ISS, and who also regularly perform a battery of health tests on themselves. That includes ultrasounds, cognitive tests, biopsies, blood and saliva testing, skin swabs and sensorimotor tests. 

“You can do research with private individuals in space, that is the number one result [of the research],” said Dr. Dorit Donoviel in a recent interview. Dr. Donoviel is co-author of one of the papers published in Nature and associate professor in the Center for Space Medicine at Baylor College of Medicine. She’s also the executive director of NASA-funded research consortium Translational Research Institute for Space Health (TRISH), which conducts and funds cutting-edge research to improve human safety in space. 

“I’ll be honest, nobody was sure that we were going to be able to gather a reasonable amount of data, that we were going to be able to implement it, that regular people who have never had exposure to scientific research could do something that we would actually be able to analyze,” she continued, referring to the Inspiration4 mission. 

In some obvious ways, the Inspiration4 crew are far from ordinary: The mission’s leader, Jared Isaacman, is a billionaire that founded a payment processing company when he was 16; Hayley Arcenaux is a physician’s assistant at the world-renowned St. Jude Children’s Research Hospital; Sian Proctor is a pilot with a PhD who teaches geology at the college level; and Christopher Sembroski is a former U.S. Air Force journeyman whose long career as an aerospace engineer brought him to his current workplace, Blue Origin.

And yet, they still came to Inspiration4 as spaceflight novices. That meant TRISH researchers had to come up with a testing suite that could be performed with minimal training. The Inspiration4 crew also wore Apple Watches, and the capsule was outfitted with environmental sensors that researchers were able to correlate to the other testing results. Correlating the data is “unusual,” Dr. Donoviel said, but it gave researchers unique insights into how changes in the confined environment affected things like heart rate or cognitive performance. 

Overall, researchers are trying to move toward digitizing testing and making more of the data-gathering passive, to lower the cognitive overhead on the private astronaut. (NASA astronauts also take cognitive tests, but they are using a very old test developed in the 1970s, Dr. Donoviel said.) 

Gathering such information will be critical as the number of private citizens heading to space increases, as it seems almost certainly poised to do in the coming decade. Researchers will be better able to understand the effects of spaceflight on people that don’t fit the mold of the typical NASA astronaut: male, white and in the top percentiles for physical and cognitive performance. But they’ll only be able to do so if the future space tourists are willing to collect the data. 

More data means a better understanding of how spaceflight affects women versus men, or could help future space tourists with pre-existing conditions understand how they will fare in the zero-G environment. The results from Inspiration4 are promising, especially for space tourism: TRISH’s paper found, based on the data from that mission, short-duration missions do not pose significant health risks. This latest preliminary finding adds to existing data that longer-term stints in space — in this case, 340 days — may not be as dangerous as once presumed.

So far, commercial providers ranging from Axiom Space to SpaceX to Blue Origin have been more than willing to work with TRISH, and agreed to standardize and pool the data collected on their respective missions, Dr. Donoviel said.  

“They’re all competing for these people [as customers], but this allows them to contribute to a common knowledge base,” she added.  

This is only the beginning. The rise in non-governmental spaceflight missions raises major questions related to the norms, ethics and regulation of human research in space. While more private citizens are likely headed to space than ever before, will they be interested in being guinea pigs in order to further scientific research? Will a private astronaut paying $50 million for a luxury space tourism experience want to spend their time in orbit conducting ultrasounds on themselves or meticulously measuring their temporary cognitive decline? 

Possibly; possibly not. Last year, Donoviel co-published an article in Science calling for, among other things, the development of a set of principles to guide commercial spaceflight missions. One of those principles the authors called for is social responsibility — essentially, the idea that private astronauts arguably have a heightened social responsibility to advance this research.

“If you’re going to space, you’re resting on the laurels of all of the public funding that has enabled you to go to space. The taxpayers paid for all of those space capabilities that have now enabled you to go to space. So you owe the taxpayers the research,” Dr. Donoviel argued. She added that advances in wearable tech have only lowered the burden on the research participants — not just with the Apple Watch, but with tech like the Biobutton device that continuously collects many vital signs or a sweat patch.  

“We’re not going to make it miserable for you, we’re not going to poke you with a needle, we’re not going to make you do an ultrasound, but wear the Biobutton and put on the sweat patch.” 

The story has been updated to reflect that Dr. Donoviel works at Baylor College of Medicine, not Baylor University, and that NASA’s cognitive tests were developed in the 1970s.