What Health Risks Do Astronauts Face in Space?
News Desk
Islamabad: Space travelers face numerous challenges during long-duration missions, including bone and muscle deterioration, radiation exposure, and vision impairment. These issues, alongside the psychological effects of isolation, are just a few of the difficulties that need to be addressed.
As US astronauts Butch Wilmore and Suni Williams prepare to return to Earth after spending nine months aboard the International Space Station (ISS), the health risks they’ve encountered are well-documented and largely managed, though some remain uncertain.
These challenges will only become more pronounced as humanity ventures deeper into the solar system, particularly with plans to explore Mars, demanding innovative solutions to ensure the future of space exploration.
Exercise as a Key Countermeasure
Despite the attention surrounding their mission, Wilmore and Williams’ nine-month stay is considered standard, according to Rihana Bokhari, an assistant professor at the Center for Space Medicine at Baylor College. While most ISS missions typically last around six months, some astronauts stay up to a year, and researchers are confident in their ability to maintain astronaut health for these durations.
While people often associate lifting weights with muscle and bone strengthening, basic movement on Earth is constantly resisted by gravity, a force absent in orbit. To counter this, astronauts use three exercise machines aboard the ISS, including a resistance device installed in 2009 that simulates free weights using vacuum tubes and flywheel cables.
Astronauts follow a strict two-hour daily workout regimen to maintain their physical condition. “The best result we have to show that we’re being very effective is that we don’t really see fractures in astronauts when they return to Earth,” said Bokhari, though some bone loss is still detectable in scans.
Another challenge astronauts face is balance disruption, which occurs in all astronauts, even those in space for just a few days, according to Emmanuel Urquieta, vice chair of Aerospace Medicine at the University of Central Florida. Astronauts need to retrain their bodies to regain trust in their inner ear during NASA’s 45-day post-mission rehabilitation program.
Fluid Shift and Vision Issues
In microgravity, bodily fluids shift towards the head, a phenomenon known as “fluid shift.” This can increase calcium levels in the urine, raising the risk of kidney stones.
Fluid shifts may also lead to increased intracranial pressure, which alters the shape of the eyeball and can cause spaceflight-associated neuro-ocular syndrome (SANS), resulting in mild-to-moderate vision impairment. Some researchers also suspect that elevated carbon dioxide levels could be a contributing factor.
Interestingly, in one case, the effects were beneficial. NASA astronaut Jessica Meir experienced a severe case of SANS, and as a result of globe flattening, she no longer needed corrective lenses, ending up with 20/15 vision.
“I had pretty severe SANS,” Meir said before her latest launch. “When I launched, I wore glasses and contacts, but due to globe flattening, I now have 20/15 vision – the most expensive corrective surgery possible. Thank you, taxpayers.”
Radiation Risks and Management
Radiation levels aboard the ISS are higher than on Earth due to the station passing through the Van Allen radiation belt, though Earth’s magnetic field still provides significant protection. NASA aims to keep astronauts’ increased lifetime cancer risk within a 3% threshold.
However, missions beyond Earth’s orbit, such as to the Moon or Mars, will expose astronauts to even greater levels of radiation, as explained by astrophysicist Siegfried Eggl. While future space probes may provide some warning of high-radiation events like coronal mass ejections (plasma clouds from the Sun), cosmic radiation remains unpredictable.
Radiation shielding is best achieved with heavy materials like lead or water, though this requires vast quantities, says Eggl. One potential solution is to create artificial gravity by rotating spacecraft, which could help astronauts stay functional after a nine-month journey to Mars.
Alternatively, spacecraft could use powerful acceleration and deceleration to simulate Earth’s gravity, which would speed up travel and reduce radiation exposure. However, this approach would require nuclear propulsion technologies that are not yet available.
Psychological Challenges
Preventing interpersonal conflicts within space crews will also be essential, warns Joseph Keebler, a psychologist at Embry-Riddle Aeronautical University. “Imagine being stuck in a van with anybody for three years: these vessels aren’t that big, there’s no privacy, no backyard to go to,” Keebler notes. “I really commend astronauts who commit to this. It’s an unfathomable job.”
