Mars mission may destroy astronauts’ kidneys, study finds

Authors of a new study published in "Nature Communications" indicate that astronauts' kidneys may be almost completely destroyed during a mission to Mars. They primarily cite cosmic radiation as the cause.

It has long been known that space flights are not indifferent to health. During such events, bone mass is lost, the heart weakens, vision is impaired, and kidney stones can form. This is largely a consequence of exposure to cosmic radiation – galactic rays, solar wind, and altered gravitational conditions.

While astronauts in low Earth orbit are protected from such rays by Earth's magnetic field, they are deprived of such protection further out, such as during a flight to the Moon.

In a project led by experts from University College London and involving 40 institutions from five continents, scientists examined the possible impact of long-term space travel on the kidneys. They analyzed physiological, anatomical, and biochemical data collected from humans and mice during over 40 low-Earth orbit flights and data gathered during space travel simulations using mice and rats.

Researchers exposed mice to cosmic radiation, simulating a manned mission into deep space lasting from 1.5 to 2.5 years, approximately 3.6 to 6.0 years. The results indicate that animal and human kidneys undergo significant changes in space conditions. For example, structures responsible for maintaining proper ion concentration in the blood shrink after just one month in space. This is most likely a result of microgravity. There is suspicion that cosmic radiation accelerates these changes.

The most alarming results, however, came from long-flight simulations conducted on animals. The radiation encountered during a mission to Mars would lead to permanent kidney function loss.

"We know what has happened to astronauts on the relatively short space missions conducted so far, in terms of an increase in health issues such as kidney stones. What we don’t know is why these issues occur, nor what is going to happen to astronauts on longer flights such as the proposed mission to Mars," notes Dr. Keith Siew, the study's lead author.

Despite their findings, scientists do not rule out the possibility of organizing long-distance missions. However, they emphasize considering the consequences of these missions on astronauts' kidneys and ways to eliminate risks.

"Our study highlights the fact that if you’re planning a space mission, kidneys really matter. You can’t protect them from galactic radiation using shielding, but as we learn more about renal biology it may be possible to develop technological or pharmaceutical measures to facilitate extended space travel. Any drugs developed for astronauts may also be beneficial here on Earth, for example by enabling cancer patients’ kidneys to tolerate higher doses of radiotherapy, the kidneys being one of the limiting factors in this regard," says Prof. Stephen B. Walsh, one of the researchers.