American astronauts Barry „Butch” Wilmore and Suni Williams are returning to Earth after a planned mission on the International Space Station (ISS) for eight days that ended up lasting nine months due to technical issues with the Starliner spacecraft.
During this time, they participated in scientific experiments, repairs, and missions outside the spacecraft. The journey back to Earth will take 17 hours, and the return will be filled with both physical and psychological challenges. How will their bodies feel the impact of gravity? What effects has isolation had on them?
An Unexpectedly Long Stay
Wilmore and Williams launched to the ISS on June 5, 2024, to test the Starliner spacecraft, developed by Boeing as an alternative to SpaceX's Crew Dragon.
The mission quickly became complicated: helium leaks, faulty thrusters, and fuel valve issues forced NASA to make a drastic decision: the spacecraft was sent back to Earth without a crew.
The astronauts were thus stranded on the ISS, where they continued scientific activities and even contributed to technical repairs. "The space station is my happy place," said Suni Williams during the mission.
Effects of Gravity on the Body
After nine months in weightlessness, the human body undergoes major transformations. Muscles atrophy, bone density decreases, and even the heart is affected, as it no longer needs to pump blood against gravity.
While in space, "fluids accumulate in the head, so astronauts feel a constant cold," explains Alan Duffy, an astrophysicist at Swinburne University, to The Guardian.
Additionally, the lack of gravity affects fluid circulation in the body, leading to fluid buildup in the head.
Also, the sense of smell is diminished, "which, in fact, is a good thing because it smells terrible there," adds Alan Duffy, referring to a spaceship without windows that open.
Radiation – The Greatest Danger
Exposure to cosmic radiation is one of the most serious issues of space travel. On Earth, we are protected by the planet's magnetic field, but in space, radiation can affect DNA and increase the risk of cancer.
According to NASA, astronauts are exposed to three main sources of radiation: particles trapped in Earth's magnetic field, energetic solar particles from the Sun, and galactic cosmic rays. The latter are described by the National Oceanic and Atmospheric Administration (NOAA) as "a constant source of extremely energized particles bombarding Earth from outside our solar system, likely generated by explosions such as supernovae."
Protection against radiation is one of the main challenges that scientists are trying to solve before sending humans to Mars or the Moon for longer periods.
Difficulty of Return
Beyond the physical challenges, astronauts also face psychological difficulties upon their return.
After spending months in a controlled environment, returning to everyday life can be overwhelming.
However, anxiety and depression are common upon return to Earth, Tucker states, due to the prolonged period spent in extreme conditions.
Astronauts may also experience the "overview effect" – a profound change in perspective caused by seeing Earth from above, like from a fragile spacecraft floating in the vastness of space.
And then, they must return to everyday life. "They have to have breakfast and go to work," he says. "It's a huge transition, from an inspirational environment to the daily routine."
D.D.