Astronauts undergo significant psychological and physiological changes during extended periods in a microgravity environment.
After spending 371 days in space, NASA astronaut Frank Rubio returned to Earth on September 27th. The 47-year-old man broke the record for the longest stay in space by a U.S. astronaut earlier this year after his initial 6-month mission on the International Space Station was extended by another 6 months. Rubio and his fellow crew members landed at 18:17 on September 27th in Dzhezkazgan, Kazakhstan, according to NASA.
Astronaut Frank Rubio on the ISS. (Photo: NASA).
In an episode of “Good Morning America” in August, Rubio shared that upon returning, his health would be examined by medical professionals. He would need some time to readjust to Earth’s gravity and regain balance for daily activities like walking and standing.
Experts note that spending an extended period in space, especially a year, brings about numerous changes in a person’s psychological well-being. One of the most significant changes is attributed to the microgravity environment, which allows astronauts to float inside spacecraft or during spacewalks. During this time, astronauts experience muscle mass loss and bone density reduction due to minimal usage and lack of stimulation through exercise equipment.
According to Dr. Jennifer Fogarty, Chief Scientist at the Baylor College of Medicine’s Center for Space Medicine, the most substantial changes in bone and muscle occur during the first two months of a mission and then stabilize gradually. One of the challenges returning crew members often face is the issue of orthostatic intolerance, how the body maintains a sense of position and balance when gravity changes.
“How do you coordinate motion like walking, something you haven’t done for an extended period, with maintaining balance? When you put those two together, it can create a somewhat hazardous condition,” explains Fogarty. The longer the mission, the more extended the adaptation period required. Missions lasting 4 to 6 months may require 2 to 3 days for recovery. Longer missions undoubtedly demand longer adaptation periods.
Furthermore, due to the unique characteristic of microgravity environments, bodily fluids such as blood and cerebrospinal fluid tend to shift upward from lower parts of the body to the head and eyes, leading to changes in eye and brain structure. This phenomenon is known as Spaceflight-Associated Neuro-Ocular Syndrome (SANS) and is closely associated with space travel, causing astronauts on long-duration missions to experience various changes, including elevated intracranial pressure, eye swelling, and blurry vision.
“Our blood vessels have valves to prevent blood from flowing backward when we stand up, but in a microgravity environment, there’s a significant fluid shift from the body to the head,” explains Dr. Michael Decker, Co-Director of the Center for Physiological Genomics of Spaceflight at Case Western Reserve University School of Medicine. “An increase in intracranial pressure can affect the eyes, leading to decreased visual acuity. Sometimes, when astronauts land, that vision loss may not fully recover.”
Being in a confined, isolated environment for an extended period also has various psychological effects. Research indicates that this type of environment can lead to behavioral changes, fatigue, stress, and sleep disturbances. According to Fogarty, the immune system also undergoes changes over the course of a spaceflight due to prolonged stress. Therefore, creating the healthiest possible environment for astronauts during their missions is crucial.
Scientists will examine whether Rubio has experienced any genetic changes, including those related to the immune system, similar to what astronaut Scott Kelly encountered during his 340-day stay in space from 2015 to 2016. Decker notes that 90% of these changes reverted within a few months after Kelly returned to Earth. Despite the harsh space environment, the changes astronauts experience are within expectations, and NASA always ensures they are adequately prepared before spaceflight.