Neuropsychiatric disorders arise from complex interactions between genetic and environmental factors. DNA methylation, a reversible and environmentally responsive epigenetic regulatory mechanism, serves as a crucial bridge linking environmental exposure, gene expression regulation, and neurobehavioral outcomes. During long-duration deep-space missions, astronauts face multiple stressors-including microgravity, cosmic radiation, circadian rhythm disruption, and social isolation, which can induce alterations in DNA methylation and increase the risk of neuropsychiatric disorders. Genome-wide DNA methylation research can be divided into 3 major methodological stages: Study design, sample preparation and detection, and data analysis, each of which can be applied to astronaut neuropsychiatric health monitoring. Systematic comparison of the Illumina MethylationEPIC array and whole-genome bisulfite sequencing reveals their complementary strengths in terms of genomic coverage, resolution, cost, and application scenarios: the array method is cost-effective and suitable for large-scale population studies and longitudinal monitoring, whereas sequencing provides higher resolution and coverage and is more suitable for constructing detailed methylation maps and characterizing individual variation. Furthermore, emerging technologies such as single-cell methylation sequencing, nanopore long-read sequencing, and machine-learning-based multi-omics integration are expected to greatly enhance the precision and interpretability of epigenetic studies. These methodological advances provide key support for establishing DNA-methylation-based monitoring systems for neuropsychiatric risk in astronauts and lay an epigenetic foundation for safeguarding neuropsychiatric health during future long-term deep-space missions.
DNA Methylation ; Humans ; Space Flight ; Mental Disorders/genetics* ; Epigenesis, Genetic ; Astronauts/psychology* ; Weightlessness/adverse effects* ; Epigenomics

As human deep space exploration enters a practical phase, ensuring astronaut health and safety has become a critical determinant of mission success. The cerebrovascular system, essential for maintaining brain function, is highly sensitive to environmental changes. Cerebrovascular diseases represent one of the characteristic adverse effects of deep space conditions such as microgravity and high-energy radiation, and have emerged as a frontier challenge in space medicine. Based on experiences from manned space missions, major research challenges persist, particularly the lack of experimental data specific to the lunar environment and the unclear threshold for low-dose radiation-induced injury. Elucidating the mechanisms and multifactorial interactions by which deep space environments impact cerebrovascular structure and function, and summarizing the key risk factors, pathological processes, and recent advances in monitoring and early-warning technologies for cerebrovascular diseases in lunar astronauts, and of crucial importance. A comprehensive understanding of the interplay between deep space environmental stressors and cerebrovascular injury, as well as the development of personalized prevention and intervention strategies, will provide both theoretical and practical foundations for safeguarding cerebrovascular health in future Chinese deep space missions, while promoting progress in related biomedical research, technological innovation, and international collaboration.
Humans ; Astronauts ; Cerebrovascular Disorders/etiology* ; Space Flight ; Weightlessness/adverse effects* ; Risk Factors ; Moon

With the continuous advancement of deep space exploration missions, maintaining astronaut skin health has become a critical medical issue affecting the safety and effectiveness of long-duration missions. Deep space environmental stressors, including microgravity, ionizing radiation, lunar dust exposure, and microbiome dysbiosis, can synergistically disrupt the skin barrier structure, leading to immune homeostasis imbalance and impaired wound healing. In recent years, research on skin protection in deep space has gradually evolved into a systematic "multi-dimensional integrated protective" framework. From the engineering protection perspective, optimization of multi-layer composite spacesuit structures, the use of hydrogen-rich and boron-containing shielding materials, as well as cabin temperature-humidity regulation and debris-resistant technologies, have greatly enhanced environmental defense capacity. From the biomedical protection perspective, functional hydrogels, antimicrobial dressings, and active compounds derived from traditional Chinese medicine have demonstrated remarkable potential in repairing the skin barrier, modulating immunity, and providing antioxidant defense. Meanwhile, the development of skin microecological interventions and wearable physiological monitoring systems has fostered a trend toward personalized health management. Future research should focus on elucidating the interactive mechanisms among the space environment, skin, and immune barrier, while exploring intelligent monitoring and nanotechnology-based protection strategies. Establishing a predictive and preventive skin health safeguarding system will provide comprehensive medical support for future deep space missions.
Humans ; Astronauts ; Skin/radiation effects* ; Space Flight ; Weightlessness/adverse effects* ; Wound Healing ; Extraterrestrial Environment

Long-term spaceflight exposes astronauts to multiple extreme environmental factors, such as cosmic radiation, microgravity, social isolation, and circadian rhythm disruption, that markedly increase the risk of depressive symptoms, posing a direct threat to mental health and mission safety. However, the underlying biological mechanisms remain complex and incompletely understood. The potential mechanisms of spaceflight-induced depressive symptoms involve multiple domains, including alterations in brain structure and function, dysregulation of neurotransmitters and neurotrophic factors, oxidative stress, neuroinflammation, neuroendocrine system imbalance, and gut microbiota disturbances. Collectively, these changes may constitute the biological foundation of depressive in astronauts during spaceflight. Space-related stressors may increase the risk of depressive symptoms through several pathways: impairing hippocampal neuroplasticity, suppressing dopaminergic and serotonergic system function, reducing neurotrophic factor expression, triggering oxidative stress and inflammatory responses, activating the hypothalamic-pituitary-adrenal axis, and disrupting gut microbiota homeostasis. Future research should integrate advanced technologies such as brain-computer interfaces to develop individualized monitoring and intervention strategies, enabling real-time detection and effective prevention of depressive symptoms to safeguard astronauts' psychological well-being and mission safety.
Space Flight ; Humans ; Astronauts/psychology* ; Depression/physiopathology* ; Gastrointestinal Microbiome ; Weightlessness/adverse effects* ; Oxidative Stress ; Brain/physiopathology* ; Hypothalamo-Hypophyseal System ; Neuronal Plasticity ; Pituitary-Adrenal System

During long-duration manned space missions, the complex and extreme space environment exerts significant impacts on astronauts' physiological, psychological, and cognitive functions, thereby posing direct risks to mission safety and operational efficiency. As a key bridge between the brain and external devices, brain-computer interface (BCI) technology enables precise acquisition and interpretation of neural signals, offering a novel paradigm for human-machine collaboration in manned spaceflight. Non-invasive BCI technology shows broad application prospects across astronaut selection, mission training, in-orbit task execution, and post-mission rehabilitation. During mission preparation, multimodal signal assessment and neurofeedback training based on BCI can effectively enhance cognitive performance and psychological resilience. During mission execution, BCI can provide real-time monitoring of physiological and psychological states and enable intention-based device control, thereby improving operational efficiency and safety. In the post-mission rehabilitation phase, non-invasive BCI combined with neuromodulation may improve emotional and cognitive functions, support motor and cognitive recovery, and contribute to long-term health management. However, the application of BCI in space still faces challenges, including insufficient signal robustness, limited system adaptability, and suboptimal data processing efficiency. Looking forward, integrating multimodal physiological sensors with deep learning algorithms to achieve accurate monitoring and individualized intervention, and combining BCI with virtual reality and robotics to develop intelligent human-machine collaboration models, will provide more efficient support for space missions.
Brain-Computer Interfaces ; Humans ; Space Flight ; Astronauts/psychology* ; Neurofeedback ; Cognition ; Electroencephalography ; Man-Machine Systems

The hand strength of astronauts, when they are outside the space capsule, is highly influenced by the residual pressure (the pressure difference between inside pressure and outside one of the suit) of extravehicular activity spacesuit glove and the pressure exerted by braided fabric. The hand strength decreases significantly on extravehicular activity, severely reducing the operation efficiency. To measure mechanical influence caused by spacesuit glove on muscle-tendon and joints, the present paper analyzes the movement anatomy and biomechanical characteristics of gripping, and then proposes a grip model. With phalangeal joint simplified as hinges, seven muscles as a finger grip energy unit, the Hill muscle model was used to compute the effects. We also used ANSYS in this study to establish a 3-D finite element model of an index finger which included both bones and muscles with glove, and then we verified the model. This model was applied to calculate the muscle stress in various situations of bare hands or hands wearing gloves in three different sizes. The results showed that in order to achieve normal grip strength with the influence caused by superfluous press, the finger's muscle stress should be increased to 5.4 times of that in normal situation, with most of the finger grip strength used to overcome the influence of superfluous pressure. When the gap between the finger surface and the glove is smaller, the mechanical influence which superfluous press made will decrease. The results would provide a theoretical basis for the design of the EVA Glove.
Astronauts ; Fingers ; physiology ; Finite Element Analysis ; Gloves, Protective ; adverse effects ; Hand Strength ; physiology ; Humans ; Mechanical Phenomena ; Pressure ; Space Suits ; adverse effects

BACKGROUND AND OBJECTIVES: The parameters of vestibulo-ocular reflex (VOR) are believed to indicate the quantitative value of vestibular function and the differences in them are related to the susceptibility of motion sickness. The purpose of this study was to investigate the effects of repetitive multiaxial 3-dimensional rotation training on VOR parameters. MATERIALS AND METHODS: Fifteen healthy volunteers were randomly assigned to 3 different groups according to the mode of exercise training. Aerotrim exercise was done as a method of repetitive multiaxial 3-dimensional rotation training. The changes in VOR parameters after 9 weeks of exercise training in Aerotrim training group were compared with that of other groups. RESULTS: While the values of VOR gain in Aerotrim training group after 9 weeks of exercise training were significantly lower than baseline values at rotation frequencies of 0.01, 0.04, 0.08, 0.16, and 0.32 Hz, values of VOR gain in other groups showed no difference between before and after exercise training. In all groups, there were no significant differences in VOR phase and symmetry values between before and after exercise training. CONCLUSION: This study showed that VOR parameters changed after 9 weeks of repetitive multiaxial 3-dimensional rotation training, and vestibular habituation might eventually occur. Since vestibular habituation is known to contribute to mitigating the frequency and the degree of motion sickness, we suggest that repetitive multiaxial 3-dimensional rotation training can be used as the countermeasure for student pilots or astronauts, who are often exposed to unusual motion and positional status in actual 3-dimensional space.
Astronauts ; Humans ; Motion Sickness ; Reflex, Vestibulo-Ocular

AIMTo verify the hypothesis that repeated body position change training can improve human head-down tilt (HDT) tolerance.

METHODSSix young healthy subjects were trained with repeated position change for 9 times and 11 days according to protocol of alternative head-down and head-up tilts, each time of training lasted for about 35 min. Their HDT tolerance (- 30 degrees/30 min) were determined before and after training.

RESULTS(1) Compared with the data before training, subjects' symptom scores during HDT test after training decreased significantly (6.00 +/- 3.79 vs 1.00 +/- 0.63, P < 0.05), magnitude of the decreased heart rate increased significantly (-0.6 +/- 2.5 vs -4.4 +/- 3.6, P < 0.01). (2) Before training, blood flow volume of internal jugular vein (IJV) during HDT decreased significantly and that of internal carotid artery (ICA) increased significantly at the beginning period of HDT compared with pre-HDT (P < 0.01), while blood flow volume of the common carotid artery (CCA) presented increasing trend. After training, there was no significant difference in blood flow volume of IJV between during HDT and pre-HDT, that of ICA and CCA presented decreasing trend in the final period of HDT compared with Pre-HDT.

CONCLUSIONRepeated body position change training can improve human head-down tilt tolerance. And its main causation is that headward shift of blood volume is restrained to some extend during HDT after training.

Adaptation, Physiological ; physiology ; Adolescent ; Astronauts ; Cardiovascular Physiological Phenomena ; Head-Down Tilt ; Humans ; Male ; Posture ; physiology ; Weightlessness Simulation ; Young Adult