Astronauts who spend significant amounts of time outside of Earth’s protective atmosphere are exposed to significantly higher levels of radiation. Ahead of sending astronauts on extended duration missions to Mars, NASA is looking for better ways to predict the risk radiation poses with long-term spaceflight. NASA says that astronauts who travel to the moon, Mars, and other deep-space destinations will be exposed to increased risks due to the space environment.
Ahead of these future deep space missions, NASA uses the ISS to improve its ability to predict space radiation exposure. The results from an ISS Medical Monitoring study have been published demonstrating the sensitivity of an astronaut’s DNA to radiation exposure on Earth can predict the response of their DNA during spaceflight. NASA’s method measures changes to the astronaut’s chromosomes.
NASA was trying to determine if it was possible to detect and measure radiation exposure damage in an astronaut’s body. The agency also wanted to determine any potential differences depending on the age, sex, and other measurable factors before sending the astronauts into space. Exposure to radiation increases an individual’s risk of developing cancers and other significant medical issues.
On Earth, people are protected from the most severe consequences of radiation caused by solar flares and galactic cosmic rays thanks to the atmosphere and magnetic field of the planet. Low Earth orbit missions, like the ISS, are also protected to some extent by the magnetic field of the Earth. NASA also uses shielding in the construction of the ISS and limits the amount of time astronauts spend in space.
NASA’s study considered three key measurements. First, before the astronaut flew to the ISS, their blood cells were assessed to determine a baseline chromosome status for future comparison. The blood samples were then exposed to gamma-ray radiation on Earth to measure how easily chromosome changes occurred inside the cells. That measurement was used to establish the inherent sensitivity of an astronaut to radiation. Finally, once the astronaut returned from the mission, additional blood samples were analyzed to assess changes in chromosomes.
Researchers found that older crewmembers had higher levels of baseline chromosome irregularities. NASA also found that older astronauts were more sensitive to alterations of their chromosomes compared to younger astronauts. The study results found that older astronauts may have a higher sensitivity to radiation and could be at higher risk. However, younger astronauts are believed to be more susceptible to long-term health consequences from radiation exposure in space than older astronauts.