Risk of defeats in the central nervous system during deep space missions

- Disturbances of the operating activity of astronauts are among the main limiting factors of deep space missions.
- The effects of heavy charged particles, gravitation overloads and hypo-magnetic field significantly modulate each other in combined action on organism.
- The most sensitive morphological structures to the combined action of the spaceflight factors are the hippocampus and the prefrontal cortex.
- A ground model of deep space missions must include the combined action of gamma-irradiation and irradiation by the heavy charged particles with Z > 12, as well as the effects of gravitation overloads and hypo-magnetic field. At the same time a care should be taken regarding the ground models of weightlessness, including the antiorthostatic suspension.

Space flight factors (SFF) significantly affect the operating activity of astronauts during deep space missions. Gravitational overloads, hypo-magnetic field and ionizing radiation are the main SFF that perturb the normal activity of the central nervous system (CNS). Acute and chronic CNS risks include alterations in cognitive abilities, reduction of motor functions and behavioural changes. Multiple experimental works have been devoted to the SFF effects on integrative functional activity of the brain; however, the model parameters utilized have not always been ideal and consistent. Even less is known regarding the combined effects of these SFF in a real interplanetary mission, for example to Mars. Our review aims to systemize and analyse the last advancements in astrobiology, with a focus on the combined effects of SFF; as well as to discuss on unification of the parameters for ground-based models of deep space missions.