Becoming an Astronaut: How Space Flight Affects Our Bodies
As children, many of us shared a similar professional goal: We were determined to become astronauts. Little did we know that NASA’s acceptance rate is abysmally low. In 2024, more than 8,000 people applied to become astronauts. Of that number, NASA will only choose between eight and 12 candidates.
Beyond the rigorous selection process, one aspect of being an astronaut that we likely didn’t consider as children is the effect space flight has on our bodies. With drastic changes in gravity and no atmosphere to shield us from the sun’s UV rays, several short- and long-term changes can occur in our bodies while in space.
Settle in and buckle up as we explore the effects of space flight on humans and — for those still interested — the prerequisites for becoming an astronaut.
Immediate Effects During Launch
In addition to the adrenaline spike they may feel during the famed countdown to liftoff, astronauts may experience several other physiological changes during space shuttle launches due to increased G-forces, including:
- Difficulty moving limbs.
- Tunnel vision or brief loss of consciousness.
- A reduced ability for the heart to efficiently pump blood.
- Bodily fluids shifting upward, which can cause fluid retention in the upper body.
- Discomfort in the sinuses due to changes in air pressure.
Musculoskeletal Adaptations
If you’re on a commercial mission to space, you’ll likely only be there long enough to appreciate the beauty of Earth from above, notice its curvature and maybe even experience a few sunsets or sunrises, depending on your positioning. Astronauts on extended missions will remain in space much longer. The average duration of an astronaut’s mission aboard the International Space Station (ISS) is 6 months.
Half a year is plenty of time for the lack of gravity to take a toll on your musculoskeletal system (i.e., your muscles and bones). On Earth, your body constantly uses its muscles to resist the force of gravity. In space, however, there’s no gravity to fight, so you end up using your muscles significantly less.
Over time, living in a zero-gravity atmosphere can weaken your muscles and reduce bone mass. Fortunately, astronauts can mitigate the effects of these unique conditions before, during and after a mission by engaging in a rigorous exercise routine. During their time on the ISS, astronauts exercise for about two hours a day, strengthening their bodies by using a treadmill and incorporating strength training.
Changes to the Immune System
Having lived on Earth your entire life, your immune system has adapted to function under Earth’s gravitational pull. Experiencing altered gravity in space impairs your immune system’s peak performance. In addition to microgravity, increased radiation and disrupted circadian rhythms can also impact your immune system.
A weakened immune system might result in your body fighting harder and longer to combat an infection it could easily overcome on Earth. You might also become more susceptible to infections until you return to Earth’s normal conditions and your immune system readjusts.
Psychological and Cognitive Effects
Physical changes aren’t the only effects to expect while spending an extended period in space. Being away from family and in constant close quarters with the same small group of people for months can impact your mental well-being, leading to feelings of isolation or confinement.
Astronauts prepare for these psychological effects through several strategies, including:
- Undergoing psychological resilience training before the mission.
- Participating in simulated missions to acclimate to the cognitive demands of space travel.
- Establishing a structured daily routine while in space to maintain normalcy.
- Contacting family regularly via email and video calls.
- Bringing personal items and participating in group activities and hobbies aboard the ISS.
- Having regular check-ins and psychological assessments.
Do You Have What It Takes for a Trip to Space?
While astronauts face several mental and physical hurdles as they embark on expeditions in space, they’re also pioneering scientific research that could change the future of science, technology and the way we live. Although many people believe they have what it takes to become an astronaut, it requires more than just determination. In addition to being a U.S. citizen and having a minimum of three years of related professional experience, you need a master’s degree in a STEM field from an accredited institution.
Whether you aspire to become an astronaut or you’re interested in turning your fascination with the human body into a lucrative career, the University of Florida offers several online graduate programs ideal for those interested in advancing their careers in health and sciences:
Our online programs in medical physiology, offered by one of U.S. News’ top 50 national universities, also boast the following benefits:
- Affordable tuition rates.
- Year-round start dates.
- No GRE requirement.
- Flexible coursework completion on your timeline.
Take the first step in advancing your career in the expansive and profitable world of STEM — apply today!
Sources:
https://touroscholar.touro.edu/cgi/viewcontent.cgi?article=1077&context=sjlcas
https://www.kennedyspacecenter.com/blog/the-20-most-frequently-asked-questions-about-the-international-space-station
https://www.nasa.gov/missions/station/scientists-probe-how-long-term-spaceflight-alters-immunity/
https://www.abc.net.au/news/health/2024-03-09/preparing-human-mind-space-travel-mars-astronauts-mission/103563280
