Exposure to radiation can affect DNA: Astronauts on long-duration missions in space at risk – India Today

As countries rush to the Moon, with plans afoot for future manned exploration of Mars and beyond, one of the biggest threats to astronauts is being exposed to radiation in space. Researchers at the International Space Station (ISS) have now detected and measured the radiation exposure damage to astronauts during spaceflight.

Astronauts on board the flying outpost have continuously been studying ways to reduce the risks of the hazards of spaceflight and develop capabilities to predict space radiation exposure for future exploration missions.

In a study published in the journal Nature-Scientific Reports, scientists demonstrate how the sensitivity of an individual astronauts DNA to radiation exposure on Earth can predict their DNAs response during spaceflight as measured by changes to their chromosomes.

As part of the research, scientists studied blood samples of 43 crew missions taken pre-flight and post-flight. While pre-flight blood samples were exposed to varying doses of gamma rays, post-flight blood samples were collected shortly and several months after landing.

Japanese Aerospace Exploration Agency astronaut Akihiko Hoshide poses for a photo after undergoing a generic blood draw in the European Laboratory/Columbus Orbital Facility (COF). (Photo: Nasa)

We wanted to know if it is possible to detect and measure radiation exposure damage in the bodies of astronauts, and if there were differences based on age, sex, and other factors that could be measured before they go into space, said senior scientist Honglu Wu from Nasas Johnson Space Center. Researchers studied the impact of these radiations on the chromosomes of astronauts. Chromosomes contain our bodies' DNA building blocks, and altering them can increase the risk of developing cancer and other diseases.

During the experiment, scientists measured the levels of chromosome alterations from radiation and other factors before and after a mission. These alterations to chromosomes are observed in a very small percentage of individual cells within a persons blood.

As part of the study, scientists conducted three measurements, first, they analysed blood samples of astronauts before they flew to the ISS, to assess their baseline chromosomal status, then these blood samples were intentionally exposed to gamma-ray radiation on Earth to measure how easily the cells accumulate changes, and third, after the astronauts returned from their missions, the study team again took blood samples from the individuals to assess their level of chromosomal alterations.

Blood samples taken by former NASA astronaut Chris Cassidy before aboard the International Space Station. (Photo: Nasa)

Following the deep analysis of samples scientists found:

The ISS is permanently exposed to several radiations emerging from the vastness of the cosmos including continuous bombardment of particles from the Sun. Space radiation originates from Earths magnetic field, particles shot into space during solar flares, and galactic cosmic rays, which originate outside our solar system.

Older crew members had higher levels of baseline chromosomal irregularities. (Photo: Nasa)

Continuous exposure to these radiations can lead to cancer alterations to the central nervous system, cardiovascular disease, and other adverse health effects. While astronauts are protected from major radiation in low-earth orbit, due to Earths magnetic field, spacecraft shielding and a limited time in space, these factors would dramatically change for long-duration missions.

Therefore, studying these changes is critical so that new ways and medical treatments can be devised.