With the pending return to long-duration crewed spaceflights, astronauts will face significant risks from exposure to space radiation. Galactic cosmic rays (GCRs) pose a particular challenge as they are not easily shielded and have dose rates as high as 0.5 mGy/day.
Sustained irradiation to the central nervous system is a major concern, both for long-term astronaut health and overall mission success. Studies in rodents have demonstrated behavioural changes following exposure to radiation doses as low as 50 mGy. Patients treated with radiotherapy have also experienced cognitive and memory impairments, albeit at much higher radiation doses. But accurate risk estimation for astronauts is difficult, in part due to the technical challenges of emulating the broad-spectrum GCR field in a laboratory.
In recent years, the NASA Space Radiation Laboratory has used a new GCR simulator (GCRSim) for its radiobiology experiments. The GCRSim spectrum includes 33 ion–energy combinations and closely resembles the radiation environment that astronauts will experience on journeys to the Moon and Mars.
Now a research team from Harvard University and Massachusetts General Hospital has performed the first nanometre-scale computational analysis of GCRSim in a realistic neuron geometry. The team hopes that the simulations, presented in Physics in Medicine & Biology, will help researchers performing GCRSim experiments interpret biological data.
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