From gravity to weight
In June 2024, American astronauts Sunita Williams and Barry Wilmore began their duties aboard the International Space Station. An eight‑day plan turned into an extended stay when a technical problem with the Boeing crew capsule blocked an immediate return to Earth. Ground teams explored options while the crew remained on the station. Officials initially targeted a return by the end of March, but flight windows can shift, turning a short mission into a near ten‑month stay in orbit.
Williams later spoke with students about the importance of staying physically fit during spaceflight. The health of the crew has been a concern after months in microgravity. In space the body burns calories as it adapts to reduced gravity and extreme conditions, making nutrition and conditioning essential. Astronauts follow a demanding routine, about two and a half hours of exercise each day, to protect muscle and bone health and to meet energy needs.
Without a carefully planned diet and training, returning astronauts may face reduced mobility on Earth. The shift from gravity to weightlessness is a demanding transition that requires preparation, rehabilitation, and time.
What does a person feel when entering space? In the early days many experience space adaptation symptoms caused by changes in the perception of gravity. Dizziness, headaches, and vision changes are common as the brain and vestibular system adjust. Most symptoms ease within a few days, allowing the crew to settle into their new environment. To aid the readaptation, the crew remains aboard until newcomers are accustomed to the station conditions.
Experts note that even the best trained professionals confront the challenge of switching to weightlessness. The brain and balance systems adapt, and spatial perception can shift in ways that affect overall health during a long stay in space and after returning home.
After the adaptation period, general health often stabilizes, but the effects of the space environment can persist. The experience may bring physical deconditioning and mental strain from prolonged isolation, requiring ongoing care and monitoring.
Around the radiation!
Radiation exposure in space is a major concern. It arises from galactic cosmic rays, solar particle events, and trapped radiation belts. The combination of high energy particles can limit how long a person can stay in space with current shielding, prompting careful planning for extended missions when shielding is insufficient.
Galactic radiation can affect the central nervous system and cognitive function. The body becomes more vulnerable, and spacecraft shielding is not perfect. Scientists are actively pursuing better protective materials and spacecraft design to reduce exposure for crews on future missions.
With ongoing research and protective strategies, some adaptation is possible, but there is no definitive solution yet. Work continues to test new materials, protocols, and countermeasures to safeguard long‑term crews.
Is restoration possible?
Space medicine specialists agree that recovery after a mission depends on many factors. Regardless of age or gender, leaving Earth presents a difficult adjustment period, and readaptation can take longer after longer flights.
Without regular exercise in space, muscles atrophy and bone density declines. Rebuilding mass requires targeted workouts and time. Astronauts commit significant hours to exercise, with rest and station maintenance occupying the remainder of each day. Rehabilitation after flight involves a team of medical professionals who monitor physical and mental health and study how space affects the human body.
Researchers have not found a simple rule linking years in space to health outcomes, but signs of lasting changes can persist after landing. The quest to improve life off Earth continues, with concepts like gravity‑simulating centrifuges under study. While these ideas are not yet ready for routine use, progress points toward easier readaptation for future crews.
Thus Williams and Wilmore may require years to fully restore their health after the flight, under ongoing medical oversight and rehabilitation programs.