Evaluation of deep space exploration risks and mitigations against radiation and microgravity

Ionizing radiation and microgravity are two considerable health risks encountered during deep space exploration. Both have deleterious effects on the human body, such as weakening the immune system, delaying wound healing and disruption of the correct functioning of the musculoskeletal, cardiovascular, and sensorimotor systems. Ionizing radiation originates from three sources in space: galactic cosmic radiation, solar particle events and solar winds. Furthermore, inside the spacecraft and inside certain space habitats on Lunar and Martian surfaces, the crew is exposed to intravehicular radiation, which arises from nuclear reactions between space radiation and matter. In this respect, the nature and amount of secondary radiation depends on the composition of the vehicle/habitat’s materials and can be more harmful than primary radiation. Besides the approaches already in use, such as radiation shielding materials (such as aluminium, water or polyethylene), alternative shielding materials (including boron nanotubes, complex hybrids and composite hybrid materials) and active shielding (using fields to deflect radiation particles) are being investigated for their abilities to mitigate the effects of ionizing radiation. From a biology point-of-view, it can be predicted that exposure to ionizing radiation during missions beyond Low Earth Orbit (LEO) will affect the human body in undesirable ways, e.g. increasing the risks of cardiovascular and central nervous system diseases, carcinogenesis, as well as accelerated ageing. Therefore, it is necessary to assess the risks related to deep space exploration and to develop mitigation strategies to reduce these risks to a tolerable level. By using biomarkers for radiation sensitivity, space agencies are developing extensive personalised medical examination protocols to determine an astronaut’s vulnerability to radiation. Moreover, researchers are developing pharmacological solutions (e.g. radioprotective agents, drugs) to proactively or reactively protect astronauts during deep space exploration. In conclusion, research is necessary to develop more effective countermeasures for use in future human space missions, which can also lead to improvements to medical care on Earth. This presentation will discuss the risks space travel outside LEO poses to astronauts, methods to monitor astronauts’ health, and possible approaches to mitigate these risks.