When astronauts leave Earth’s protective magnetosphere, they are exposed to higher levels of harmful radiation from outside of our galaxy. Particles in these galactic cosmic rays (GCRs), like high-energy ions, can penetrate through human skin, passing on energy to cells and damaging its DNA. Ultimately, this could lead to an increased risk of diseases such as cancer for astronauts in the long-term and could cause radiation sickness during missions.
In order to help understand and mitigate the damaging effects of GCRs, researchers from the NASA Langley Research Center, USA, have built a ground-based GCR simulator at the NASA Space Radiation Laboratory (NSRL), located at Brookhaven National Laboratory. Capable of rapidly and repeatedly switching between the various ion types and energy intensities that make up GCRs, this simulator is a more accurate testing environment for radiation shielding and other mitigating measures than previous versions.
Hardware and software upgrades to the GCR simulator were carried out a few years ago, which have enabled these experiments to take place. “With the upgrades we can simulate different types of ion rain with multiple types of ions sequentially versus only one type of ion at a time.” NASA Space Radiation Medical Countermeasure Lead Dr Lisa Carnell explained in a statement, released when the upgrades were first announced.
Since then, great feats have been achieved at the site. In June 2018, 33 unique ion-energy beam combinations were sequentially delivered in under 75 minutes, which provides a proxy for the GCR environment experienced by shielded astronauts on a deep space mission. The next milestone was achieved in October 2019 when the simulator delivered radiation in smaller daily doses to three animal model systems over a period of four weeks. Led by space radiation element scientist Lisa Simonsen of the NASA Langley Research Center, researchers studied the impact of this mixed-field radiation on the risks of radiogenic cancers, cardiovascular disease, and adverse effects on the central nervous system.
Studies such as this one, published in PLOS Biology, will help scientists to better understand the impact astronauts' bodies are under in deep space, and develop effective preventative measures to reduce radiation exposure. One such idea already discussed is the use of underground lava tubes on the Moon and Mars to offer some protection against GCRs and other harmful radiation.