The two astronauts currently ‘stranded’ in space are facing potential physiological challenges due to their extended stay in orbit.
Sunita Williams and Butch Wilmore initially departed for the International Space Station (ISS) on June 5, with plans to remain there for just eight days. However, due to unresolved issues, their mission is now expected to last eight months.
Complications arose when the crew identified significant helium leaks and thruster malfunctions, rendering the Boeing capsule too hazardous for their return journey. As a result, the astronauts will likely return to Earth with SpaceX’s Crew-9 flight in February 2025.
There remains a possibility of an earlier return if the Boeing Starliner can be successfully repaired.
NASA provided an update on August 15, noting that Williams and Wilmore are ‘doing great,’ but the prolonged duration in space may have physiological consequences.
Even brief space flights of two weeks can result in a 20 percent loss of muscle mass in astronauts. Longer missions, around six months, can see this loss rise to 30 percent, according to a 2009 study titled: ‘Acclimation during space flight: effects on human physiology’.
Postural muscles, such as those in the back, neck, calves, and quadriceps, are particularly impacted due to the lack of gravity, which they are used to resisting on Earth.
Angelique Van Ombergen, Lead of Life Sciences at the European Space Agency, explained in a YouTube video: “When astronauts spend several months in space, they can lose up to 20% of their muscle mass, and also their bone density decreases.
“Since the whole body is exposed to microgravity, the heart doesn’t need to pump around as much blood as it used to on Earth and the cardiovascular system deteriorates.”
Astronauts often experience neurovestibular acclimation, which refers to the neurological disturbances caused by microgravity during space flight.
This acclimation usually affects astronauts during the initial days of their mission and again when they re-adapt to Earth’s gravity upon their return, as reported in the 2009 study.
Symptoms include facial pallor, cold sweating, stomach awareness, nausea, and sometimes vomiting.
Over time in space, astronauts can lose one to two percent of their bone mass each month.
This is significantly higher compared to the 0.5%-1% annual bone mass loss experienced by elderly people on Earth, according to BBC.
To mitigate this, Williams and Wilmore will need to engage in 2.5 hours of exercise daily.
NASA states that Earth’s magnetic field protects humans from space radiation, but astronauts in space are exposed to a variety of increased radiation levels.
“Three major sources contribute to the space radiation environment: particles trapped in Earth’s magnetic field, solar energetic particles from the Sun, and galactic cosmic rays,” NASA’s website further explains.
Prolonged exposure to such radiation can heighten the risk of cancer and degenerative diseases like heart disease for astronauts.