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We are about to learn a lot more about how the human body reacts to space.

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

A sign that rebirth is imminent appeared earlier this week, when Nature magazine published a stash of papers detailing the physical and mental changes the four-person crew of the Inspiration4 experienced nearly three years ago. That mission, in collaboration with SpaceX, released 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 declines in cognitive performance. But researchers can only analyze the data — more than 100,000 health-related data points — because the four-person team was able to reliably collect it in the first place.

This is a greater achievement than one could imagine. The Inspiration4 crew received a lot of training, much of it with SpaceX, which provided them with the Dragon capsule for their trip into orbit. But their preparation is still far from that of NASA astronauts aboard the ISS, who also periodically undergo a series of health tests. That includes ultrasounds, cognitive tests, biopsies, blood and saliva tests, skin swabs, and sensorimotor tests.

“Research can be carried out with individuals in space, that is the number one result [of the research]”said Dr. Dorit Donoviel in a recent interview. Dr. Donoviel is a co-author of one of the papers published in Nature and an associate professor at the Center for Space Medicine at Baylor University. She is also executive director of the 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, no one was sure that we were going to be able to collect a reasonable amount of data, that we were going to be able to implement it, that normal people who had never been exposed to scientific research would be able to do something that we could actually analyze,” he continued, referring to the Inspiration4 mission.

In some obvious ways, the Inspiration4 team is far from ordinary: Mission leader Jared Isaacman is a billionaire who founded a payment processing company when he was 16; Hayley Arcenaux is a physician assistant at the world-famous St. Jude Children’s Research Hospital; Sian Proctor is a pilot with a PhD who teaches geology at university level; and Christopher Sembroski is a former US Air Force officer whose long career as an aerospace engineer led him to his current workplace, Blue Origin.

The Inspiration4 team.
Image credits: Inspiration4

And yet, they came to Inspiration4 as spaceflight novices. That meant TRISH researchers had to devise a set of tests that could be performed with minimal training. The Inspiration4 crew also wore Apple watches and the capsule was equipped with environmental sensors that the researchers were able to correlate with the results of other tests. 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.

In general, researchers are trying to move toward digitizing testing and making data collection more passive, to reduce the cognitive overload of the private astronaut. (NASA astronauts also perform cognitive tests, but they do so using pencil and paper, Dr. Donoviel said.)

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

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

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

“Everyone is competing for these people. [as customers]but this allows them to contribute to a common knowledge base,” he added.

This is just the beginning. The rise of nongovernmental spaceflight missions raises important questions related to the standards, ethics, and regulation of human research in space. While more private citizens than ever are likely headed to space, will they be interested in being guinea pigs to promote scientific research? Would a private astronaut paying $50 million for a luxury space tourism experience want to spend his time in orbit getting ultrasounds or meticulously measuring her temporary cognitive decline?

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

“If you go to space, you are resting on the laurels of all the public funding that has allowed you to go to space. Taxpayers paid for all those space capabilities that have now allowed them to go into space. So we owe the research to the taxpayers,” Dr. Donoviel argued. He added that advances in wearable technology have only reduced the burden on research participants, not just with the Apple Watch, but with technology like the Biobutton device that continually collects many vital signs or a sweat stain.

“We are not going to make things miserable for you, we are not going to prick you with a needle, we are not going to force you to have an ultrasound, but rather to use the Biobutton and put on the sweat patch.”