Astronauts' bodies change quickly in orbit, and those changes are giving medical researchers on Earth new ways to study ageing, prolonged immobility and disease, according to reporting by the Portuguese broadcaster RTP. The outlet spoke with German astronaut Matthias Maurer, who flew for the European Space Agency (ESA) and spent time aboard the International Space Station (ISS), about what happens to the human body without gravity. RTP reports that the same research serving future space missions is also being directed at clinical problems on Earth.
Why it matters
In microgravity, the body's fluids shift upward from the legs toward the head within hours, the face swells, and the organism begins adapting to life without weight, RTP reports. Over months, muscles and bones weaken, the heart works differently and vision can be affected. RTP notes that these effects are a risk for anyone hoping to reach Mars, but they also give scientists rare windows into processes resembling ageing, and into the effects of radiation and ways to protect and treat patients on Earth.
RTP describes the human body as a multi-part organism — bones, muscles, organs and a great deal of fluid, roughly 60 percent water — that is already malleable and changing over time, and that undergoes even more change under microgravity. According to the outlet, knowledge gathered in space can be brought back to Earth and applied to ageing, immobilisation, radiotherapy and other clinical areas. Many investigations now conducted in these settings are not aimed only at future space travel, RTP reports, but also at using that knowledge to treat illness and patients on Earth.
What an astronaut's body shows
Maurer told RTP Notícias that the changes were visible almost immediately. He described how a photo taken before launch and another taken about two hours later appear to show him having gained several kilos in a few hours, when in reality the fluid that had been in his legs and feet was floating through his body and collecting in his face. RTP reports that Maurer served as both researcher and research subject during his stay on the ISS, with his body observed before, during and after the mission to understand how the human organism reacts outside the conditions in which it evolved. He said the work is essential to understanding how the human body adapts to space, and how it adapts to ageing both in space and on the ground.
RTP reports that human cells carry out their changes about 20 times faster in microgravity. Without the effort imposed by Earth's gravity, the body responds to its surroundings and behaves as though it no longer needs the same muscle and bone mass. For that reason, astronauts exercise for around two hours a day to counter muscle loss, reduced bone density and cardiovascular deconditioning, according to the outlet.
Some of these changes resemble processes seen on Earth during ageing, extended immobilisation or certain illnesses, RTP reports, but in space they develop over a much shorter period. That acceleration makes astronauts a study model, the outlet notes, though it does not fully reproduce human ageing.
Radiation and eyesight as obstacles to Mars
RTP asked whether the picture is encouraging enough to prepare for a mission to Mars or to plan future exploration. Maurer's answer, as reported by the outlet, was that at present it is not. He cited two main reasons he described as too harmful to the human body. The first is radiation: he said that flying to Mars and back would probably expose an astronaut to enough radiation to raise the risk of cancer on Earth by 15 percent compared with the normal risk. The second concerns the eyes — he said that living in zero gravity causes changes in the eyes that could leave a crew blind by the time they arrived at Mars.
RTP reports that not all changes disappear when an astronaut returns to Earth. One of the biggest concerns remains the eyes and the brain: without gravity, the redistribution of fluids can alter pressure in the head and affect structures linked to vision. According to the outlet, medicine is still trying to understand why some astronauts are more affected than others, and to what extent the changes can persist.
RTP's reporting also places the subject in a wider context of public and scientific interest in space, referencing a symposium on science and space and noting that the knowledge is gathered in order to prepare better. The outlet's account makes clear that the research runs in two directions at once: protecting the people who travel beyond Earth, and learning from their bodies to help patients who never will.
Watch for further findings from ISS-based human physiology studies and from ESA's astronaut health programme, as researchers continue to test how far space-derived knowledge can be translated into clinical care on Earth.
