In order to examine how being in outer space impacts human health, astronauts Nichole Ayers (NASA) and Takuya Onishi (JAXA) take blood samples on the International Space Station (ISS). Changes in physiological functions caused by microgravity can lead to an increased risk of having kidney stones during missions lasting for long periods of time.Image Credit: NASA
When we think about the challenges of sending astronauts to Mars, our thoughts revolve around the effects of radiation, spacecraft design, and psychological aspects of being isolated for a long period. However, one of the medical concerns that NASA is aware of with regard to long-term space missions is something far more familiar: "kidney stones".
While there are no recorded instances of an astronaut experiencing a symptomatic stone during a mission, NASA has concluded that renal stones are a potential major risk in regard to space missions of extended duration. This is due to the lifestyle adaptations caused by living in microgravity.
In space, since they no longer have to support their body weight, astronauts lose bone mineral. This causes calcium to enter their blood, which in turn increases calcium excretion in their urine. Due to fluid and urine changes, this makes them at greater risk of forming kidney stones.
On the International Space Station, if something serious happens, a solution is often to bring the astronaut back to Earth; going to Mars is totally different. The round-trip would take about two or three years and there would be a delay of 22 minutes for communication. In this situation, there would be no chance of quick evacuation.
To reduce the risk of medical problems as much as possible, they have to go through many medical tests before their journey in space. They have to exercise in order to avoid losing bone mass, take care of their hydration needs, and constantly monitor their urine. NASA has set certain procedures to prevent formation of kidney stones when on a mission.
In addition to developing more powerful rockets, agencies that are planning to send astronauts beyond low Earth orbit must give consideration to their health. One case of how space medicine can improve safety in future travel is learning about ongoing prevention of kidney stones.
References
NASA Technical Reports Server. A Guideline for the Management of Renal Stones in Astronauts. https://ntrs.nasa.gov/citations/20140003290
NASA Technical Reports Server. Evidence Report: Risk of Renal Stone Formation. https://ntrs.nasa.gov/search.jsp?R=20170004709
