Emerging Peril for Astronauts Bound for Mars
Astronauts journeying to Mars and back may face an unexpected health risk in the form of “cosmic kidney disease,” a condition far less glamorous than it sounds. Recent research indicates that the unique conditions of interplanetary travel, including prolonged exposure to microgravity and space radiation, can profoundly alter kidney structure and function, potentially leading to irreversible damage.
Dr. Keith Siew, a study author, explained the severity: “To put it in perspective, one year aboard the space station equals the radiation dose a nuclear power plant worker can safely receive over five years.” Despite the protection of Earth’s magnetic field in Low Earth orbit (LEO), deep space missions, such as a voyage to Mars lasting several years, expose astronauts to much higher levels of galactic cosmic radiation (GCR).
Previous human exposure to GCR was limited to Apollo mission astronauts who spent brief periods on the Moon, totaling no more than 12 days. In contrast, a Mars mission could entail years of such exposure, prompting concerns about its impact on organs like the kidney, known for its sensitivity to radiation.
The study analyzed data from 66 astronauts and studied rodents that had been aboard the ISS, simulating long-duration space travel. Results showed significant kidney “remodeling” after just weeks in space, with structures like the distal convoluted tubule shortening due to microgravity and radiation. This could lead to progressive and irreversible loss of kidney function, a silent threat as symptoms may not manifest until significant damage has occurred.
“The kidney is a late-responding organ,” Siew noted, highlighting that astronauts may appear healthy during missions only to face sudden kidney failure upon return, akin to a delayed onset health crisis like heart disease.
While kidney stones have been a known issue in spaceflight due to microgravity-induced bone demineralization, the study suggests that impaired kidney function itself may exacerbate this risk. Addressing these challenges will be crucial for future missions, not just for astronaut health but also to inform medical advancements on Earth, such as enhancing radiotherapy tolerance in cancer treatment.
Despite these findings, researchers caution that their acute radiation exposure models may not fully replicate the chronic effects faced by Mars-bound astronauts. This uncertainty underscores the need for continued study and potential development of technologies or pharmaceuticals to safeguard renal health during extended space travel.
In conclusion, as senior study author Professor Stephen B. Walsh emphasized, understanding and protecting kidney function will be essential for planning safe and successful future space missions.
