Elon Musk once said that humans will arrive on the surface of Mars by the year 2025. This has not happened yet because Musk is a champion of loud but empty words. But the space agencies of China, Russia and the United States each have plans to send their astronauts to the Red Planet within a generation. But all hopes may not be achieved because of the weakness of the human kidney.
Scientists from University College London published a study of the effects of microgravity and exposure to galactic cosmic radiation (GCR) on astronauts' kidneys. Based on the kidney health data of mice and astronauts who have lived a long time on the International Space Station (ISS), researchers have found that there is a risk of permanent damage to the kidneys when traveling to Mars.
Microgravity causes astronauts to develop kidney stones because the body processes salt and calcium differently than it does on Earth. When simulated exposure to Mars radiation between 1.5 and 2.5 years was carried out on mice, permanent damage was detected in the kidneys until they failed to function.
There is still time to find a solution to these two problems. If not, perhaps among the tools that need to be sent to Mars is a dialysis machine and a replacement kidney because humans cannot live without kidneys. We have already tried using pig kidneys instead of human kidneys even though all the recipients eventually died.