The research, which reveals that astronauts can lose the equivalent of decades of bone mass after returning to Earth, serves as a warning for future Mars missions.

Previous research has shown that astronauts lose 1-2 percent bone density for each month they spend in space. This is because the absence of gravity reduces the pressure on astronauts’ legs when they stand or walk.

In the new research, the wrists and ankles of 17 astronauts were imaged before they went into space, on the International Space Station and back, to find out how they improved when they set foot on Earth.

One of the authors of the study evaluating the results, Dr. Steven Boyce has stated that the loss of bone density is equivalent to the loss experienced on Earth within decades.

It was observed that astronauts who stayed on the International Space Station for four to seven months had the longest missions and had the slowest recovery. A year after returning to Earth, nine astronauts have reportedly not fully recovered.

“The longer you stay in space, the more bone loss occurs. This raises major concerns for future planned missions to Mars, which could mean astronauts spend years in space.

Stating that they do not know whether the situation will worsen over time, Dr. Boyd”After some time, bone loss can stabilize or continue. But I can’t imagine losing you until there’s nothing left” said.

The new study, published in Scientific Reports, also shows how space travel changes bone structure.

Boyd explained the situation by comparing the bones in the body to the Eiffel Tower: “Some of the metal tie rods that hold the structure up appear to have disappeared. When we return to Earth, the remaining stems thicken, but no new ones form.