The Artemis II has launched into space. While there may be technical issues, the human body will also be affected in the new environment. In fact, there are several shocking things space does to the body — and none of them are things you’d want to experience yourself.
On April 1, Artemis II lifted off from Kennedy Space Center. The four astronauts onboard — Reid Wiseman, Victor Glover, Christina Koch, and Canadian Space Agency astronaut Jeremy Hansen — have begun their journey to the Moon, marking the first lunar mission in 53 years. They will remain in space for 10 days, assuming everything goes as planned.
When astronauts leave Earth, they don’t just travel into space — they enter an environment that begins altering their bodies almost immediately. According to scientists, the changes start surprisingly fast.
In fact, just five days in space can trigger unexpected effects inside the human body — from shifting fluids to weakening muscles — revealing how extreme life beyond Earth truly is.
Fluid shifts can cause “chicken legs” and “baby feet,” as bodily fluids move upward toward the head. This can also lead to swelling and headaches.
One of the many challenges the astronauts will face is radiation exposure. Speaking with the Daily Mail, Dr. Irene Di Giulio of the Center for Human and Applied Physiological Sciences at King’s College London said the short duration of the Artemis II mission reduces long‑term health risks compared to astronauts who spend months on the International Space Station (ISS).
The shocking things 10 days in space can do to the human body
Still, radiation can cause nausea.
“Space motion sickness could also be experienced as the body needs a few days to adapt. Meanwhile, acute fluid shift from the lower part of the body to the head may cause discomfort and swelling,” she said.
“Sleep disturbances due to a sudden change in the light–dark cycle and the use of artificial lighting may be experienced. And mental stress and isolation, especially given the mission demands and living in an enclosed environment, may affect performance.”
Because the human body no longer has to fight against gravity in space, many astronauts initially find the environment comfortable. However, it also triggers a chain reaction inside the body.
For example, fluids that normally stay in the lower body move upward, often causing a puffy face and pressure in the head. At the same time, muscles and bones begin to weaken because they’re no longer being used in the same way. These changes can begin within days. Even short trips can have noticeable effects.
As many experience weight loss and muscle atrophy — since gravity isn’t there to “fight” anything — astronauts often feel much older when they return to Earth.
Bone and muscle loss
However, Dr. Di Giulio said this is unlikely to happen to the Artemis II crew.
“The impact on muscles and bones seen in longer missions may be less apparent, because they typically require a longer exposure to altered gravity,” she explained.
“However, bone loss and muscle deconditioning can begin within just a few days, as demonstrated during NASA Space Shuttle missions, which were often seven to 14 days in duration. These effects therefore remain relevant for Artemis II and highlight the importance of performing in‑flight exercise to counter the loss in bone and muscle.”
While many assume only long missions are dangerous, research shows that even short stays in space can affect the body. From balance issues to changes in blood flow, astronauts often experience symptoms that can feel disorienting at first.
Susan Bailey, professor of radiation cancer biology at Colorado State University, noted that the longer an astronaut remains in space, the more complicated their transition back to Earth becomes.
Chris Mason, a professor of genomics at Cornell University, told Discover Magazine, “It’s all very disorienting when you first get up into space, and that disorientation can last anywhere from days to sometimes weeks.”
Would you want to go to space? Please share your thoughts in the comment section.
