Most space travelers face the same debilitating ailment. The experience of 4 civilian astronauts could offer answers

“My vision acuity started to deteriorate those first few days,” Scott “Kidd” Poteet, a former US Air Force pilot, told CNN’s Dr. Sanjay Gupta in a recent interview.

His crewmate Anna Menon, a SpaceX engineer who was the Polaris Dawn mission’s medical officer, said she was struck by space adaptation syndrome. It’s a phenonmenon that affects roughly 60% to 80% of people who travel to orbit, though astronauts rarely openly discuss the ailment.

“It can be a whole spectrum of experience from lightheadedness, nausea, all the way to vomiting,” Menon said. “I experienced really the whole gamut.”

Traveling to space — with its jarring g-forces and disorienting weightlessness — can have a variety of effects on the human body, ranging from the uncomfortable to the downright dangerous.

NASA has long known about and studied these ailments, as the agency’s astronauts have reported such symptoms for decades.

But the Polaris Dawn mission — a five-day journey to orbit carried out by the private sector rather than NASA — sought to take that research further, hoping to unravel some of the most troublesome aspects of spaceflight.

During the mission, the crew carried out a variety of health-focused experiments, including wearing special contact lenses that measured the pressure in their eyes and undergoing MRI scans to track changes to the anatomy of their brains.

The Polaris Dawn team pursued those answers because the mission aims to pave the way for more people to venture into space, noted Jared Isaacman, the billionaire founder of payment technology company Shift4. Isaacman helped fund and was commander of the unprecedented mission.

“Some 600 people have been to orbit in the last 60 years — more than half have gotten space adaptation syndrome,” Isaacman said. “And you’re talking about (mostly government astronauts) — some of the most highly screened individuals. … That’s just underscoring the importance of why we have to solve this, if we’re going to put hundreds or thousands of people in space one day.”

SpaceX’s founding goal is to fly the first humans to Mars and eventually establish a settlement there.

“If you think of a future where there’s thousands of people living in space and they eventually — after nine months’ travel — you get to the surface of Mars, and a huge percentage (of people) have vision changes that make them unable to do their work, unable to read their procedures — that’s a big problem,” Menon said of why SpaceX hopes to find answers to pressing in-space medical conditions.

The ‘cyborg experiment’

During the September mission, the Polaris Dawn crew conducted the first commercial spacewalk as well as ventured into the lower band of Earth’s Van Allen radiation belts, which are areas within Earth’s magnetic field where pools of radiation from the sun lie trapped.

Initial reports from the Polaris Dawn crew did not necessarily reveal any specific health effects from radiation exposure, although Isaacman said he saw “sparkles or lights” when he closed as eyes, just as other NASA astronauts who have ventured through high-radiation environments have reported. This phenomenon is not yet well understood.

However, Poteet said his vision was noticeably less sharp during the first few days in space, which may point to a condition called spaceflight associated neuro-ocular syndrome, or SANS.

NASA estimates as many as 70% of astronauts experience this condition, which may be caused by shifting bodily fluid, resulting in pressure changes in the eyes.

Poteet’s vision changes may have shown up in the data collected by the special contact lenses worn by the crew, which they nicknamed the “cyborg experiment.” The contacts were designed to collect data on interocular pressure over the course of their mission, Menon said.

“This is novel because you’re getting long-duration data. And you can then really better understand how that transition occurs over the course of time and especially that early time in space,” she said. “We are really interested to see what the researchers come back with when they have the chance to look through all this data.”

Dr. Allison Hayman, a researcher and associate professor at the University of Colorado Boulder, which led the cyborg experiment, said Friday that researchers had not yet received preliminary data from the mission.

In all, the Polaris Dawn team carried out 36 experiments on behalf of 31 partner institutions, including universities and NASA.

Adapting to space

Back on Earth, Poteet reported that his vision quickly returned to normal.

And while he had unfortunate vision lapses during the journey, Poteet said he was pleased to report he did not experience any of the nausea typically associated with space adaptation syndrome, which he called “fairly ironic.”

“People assume there’s a correlation between motion sickness (on Earth) and space adaptation syndrome,” he said. “I have a tendency to get motion sickness in the back of an Uber. … But I actually didn’t experience those symptoms (in space).”

Menon noted she wasn’t as lucky.

“It really gave me just a huge appreciation for how it can impact your ability to work and get things done, especially in those early adaptation days,” Menon said.

Before takeoff, Isaacman — the only crew member with previous space travel experience — told CNN that medication administered to treat space adaptation syndrome symptoms can put people to sleep for eight hours or so. (He led a previous self-funded trip to orbit called Inspiration4 in 2021.)

Sarah Gillis, a lead SpaceX operations engineer who was a mission specialist aboard Polaris Dawn, also noted that crew members had their blood drawn before and after the mission to evaluate how their bodies processed drugs — such as acetaminophen (or Tylenol) — in orbit versus on Earth.

Another experiment that the Polaris Dawn crew underwent to understand in-space ailments involved a series of MRI scans just before liftoff and immediately after returning to Earth.

The crew even had a portable imaging machine right outside their quarantine facility, Isaacman said. Doing so allowed the team to collect data even faster than NASA has collected such scans on astronauts after returning from space, Menon said.

“Even those MRI results show changes to the brain anatomy,” she said.

The changes have included brains shifting upward in astronauts’ skulls, according to Dr. Donna Roberts, deputy chief scientist at the ISS National Laboratory who has spent years researching the affects of spaceflight on brain structure. Roberts on Thursday noted that initial reviews of the MRI data “did not show any clinically concerning findings.”

Spaceflight can also enlarge fluid-filled cavities at the center of the brain, called ventricles, Roberts added.

“We don’t quite understand why that’s happening,” she said.

Gillis, whose job at SpaceX includes training NASA astronauts headed for orbit, said in a CNN interview before liftoff that “human spaceflight is not going to be glamorous all the time” because of the discomfort microgravity can wreak on the human body.

Upon her return, Gillis reflected on the effects. “It’s been so incredibly fascinating to actually go through all of those changes to see how your body responds, and how the fluid shift impacts you, and how all of your organs kind of shift inside you,” she said.

“We don’t thrive without atmosphere, without oxygen,” Gillis added. “I think that really just underscores the importance to me of the research we are doing, the data we’re collecting.”

-CNN