Each of the four astronauts on SpaceX’s Polaris Dawn mission shared unique physical experiences during their groundbreaking journey, which set a record for the highest private crewed orbit around Earth in decades.
Former U.S. Air Force pilot Scott “Kidd” Poteet reported vision impairment shortly after reaching orbit, telling CNN’s Dr. Sanjay Gupta, “My vision started to deteriorate those first few days.”
SpaceX engineer and mission medical officer Anna Menon also described feeling the effects of space adaptation syndrome, a common but rarely discussed ailment among astronauts. “It can be a whole spectrum of experience, from lightheadedness to nausea all the way to vomiting,” Menon explained.
These symptoms, ranging from discomfort to significant physical strain, have long been a focus of NASA studies on the impact of weightlessness on the human body. The privately funded Polaris Dawn mission aimed to further this research, investigating how space travel affects vision and brain anatomy through a series of groundbreaking experiments.
“Cyborg Experiment” and vision impairment studies
The Polaris Dawn crew tested new technology, including specialized contact lenses designed to track eye pressure fluctuations—a project they playfully dubbed the “cyborg experiment.” This innovation aims to address spaceflight-associated neuro-ocular syndrome (SANS), a vision issue experienced by up to 70% of astronauts. “This is novel because you’re getting long-duration data,” Menon said, “and you can then really better understand how that transition occurs over time.” Researchers hope this experiment can help prepare future missions for prolonged exposure to microgravity, especially as SpaceX works toward its ultimate goal of sending humans to Mars.
Spacewalks and radiation exposure
While the crew was exposed to potential radiation risks during their spacewalk through Earth’s Van Allen belts, no specific health issues from radiation were reported. However, crew commander Jared Isaacman, who funded the Polaris Dawn mission, did experience a familiar side effect known to NASA astronauts: seeing “sparkles or lights” while his eyes were closed. The mission included a historic commercial spacewalk, during which the crew encountered this high-radiation environment firsthand. This experience, Isaacman noted, underscores the importance of understanding radiation’s effects for extended missions beyond Earth.
Experiments on the brain and drug processing in microgravity
In addition to testing their vision, the Polaris Dawn crew conducted numerous health assessments to evaluate how space travel affects drug processing and brain anatomy. Pre- and post-mission blood tests and MRI scans were part of this effort. These tests, Isaacman explained, allowed the team to rapidly assess the effects of space on cognitive function and anatomy, including possible shifts in brain structure. Dr Donna Roberts, a leading expert in space medicine, noted that initial scans showed some anatomical changes, though there were “no clinically concerning findings.” Observed shifts included the brain moving upward in astronauts’ skulls and potential enlargement of brain ventricles, both of which are common responses to microgravity.
Reflections on adapting to space
Despite his initial vision issues, Poteet’s eyesight returned to normal soon after returning to Earth, while Menon noted her adaptation to space was less seamless. Reflecting on the mission’s physical toll, Menon acknowledged the challenge of working through symptoms. “It really gave me just a huge appreciation for how it can impact your ability to work,” she said.
SpaceX operations engineer and mission specialist Sarah Gillis emphasized the importance of this research for future space exploration. “It’s been so incredibly fascinating to go through all of those changes… I think that really just underscores the importance of the research we are doing, the data we’re collecting,” she said.
The Polaris Dawn crew, which completed a total of 36 experiments, provided crucial data to SpaceX and partner institutions on how the human body endures space travel—advancing knowledge that will be vital as humanity prepares for longer missions to Mars and beyond.