Search Results (134)

Background: Long-duration spaceflight (LDSF) poses unique challenges to ocular health as microgravity, radiation, and environmental changes can cause lasting visual and structural impairments that affect astronaut performance. Objective: This review synthesises current evidence on in- and post-flight ocular complications. It integrates clinical findings, terrestrial analogues, animal studies, and theoretical models to characterise the pathophysiology, risk factors, and countermeasures associated with spaceflight-induced ocular changes. Methods: A review of peer-reviewed literature was conducted, focusing on dry eye disease, corneal edema, ocular biometric shifts, spaceflight associated neuro-ocular syndrome (SANS), and radiation-induced cataractogenesis. Data from in-flight imaging, post-flight assessments, and ground-based analogues were analysed. Results: Spaceflight induces multifactorial ocular changes, including tear film instability, optic disc edema, posterior globe flattening, and hyperopic refractive shifts. These effects are thought to result from cephalad fluid shifts compartmentalised cerebrospinal fluid pressure, venous congestion, and impaired glymphatic system. Long-term risks, such as cataractogenesis, are linked to radiation exposure and genetic susceptibility. Although several countermeasures are being explored, no single approach fully prevents these complications. Conclusions: Ocular complications during LDSF remain a significant challenge for astronaut health and mission performance. A multimodal approach combining mechanical, nutritional, and diagnostic strategies will be essential for future exploration-class missions. Further research is needed to refine countermeasures and preserve astronauts’ visual function. Full article

Bone densitometry in osteoporosis diagnosis via dual-energy X-ray absorptiometry (DXA) can benefit from advances in imaging detector technology. We devised a compact imaging scanner—DXA4A—using a photon-counting and energy-sensitive Timepix4 hybrid pixel detector (512 × 448 pixels, 55 µm pitch), for areal bone mineral density (aBMD) assessments in the distal radius and tibia in the clinic and for future in-flight astronauts’ bone health assessment. We present the design and Monte Carlo simulations of the scanner. A Timepix4 detector with a 1 mm thick CdTe sensor was tested in the laboratory with X-ray tube sources, acquiring first images of test samples. Monte Carlo simulations were implemented for scanner design and performance prediction, using 50 kVp unfiltered and 100 kVp Sm K-edge filtered spectra. With a digital twin of the scanner and patient wrist, we set up a virtual imaging study and determined the aBMD in the forearm of a patient (0.515 ± 0.048 g/cm²), in agreement with the clinical DXA value (0.571 g/cm² for the total forearm). This study highlights the feasibility of realizing a compact DXA scanner for the distal tibia and radius with spectral capabilities, exploiting Timepix4 hybrid detectors for its peculiar energy sensitivity and photon event timing properties for tissue identification. Full article

Human pose estimation in orbit is critical for astronaut health monitoring, task assistance, and intelligent human–robot interaction aboard space stations. However, in microgravity, human poses exhibit arbitrary orientations and are often affected by severe occlusion and complex background interference, while the scarcity of annotated in-orbit data makes it difficult to directly transfer models trained on ground-based datasets. Existing semi-supervised methods also lack explicit constraints from human structural topology and pose-related physical priors, which often leads to unreasonable pseudo-labels and limits performance gains. To address these issues, we propose a physics-inspired semi-supervised pose estimation framework for microgravity scenarios. Specifically, a Canonical Orientation Constraint is introduced to alleviate orientation ambiguity; a Structure-aware Pseudo-Label Refinement module is designed to improve pseudo-label quality; and an Uncertainty-guided Rotational Consistency Framework is proposed to adaptively weight consistency learning under multi-view rotation augmentation. Within a Mean Teacher architecture, the proposed method jointly optimizes the supervised loss, orientation constraint, pseudo-label refinement, and rotational consistency objectives. Experiments on the Astro-Pose dataset show that the proposed method consistently outperforms both fully supervised and semi-supervised baselines under various extreme poses and occlusion conditions, improving AP from 47.6 to 55.6 and AR from 52.4 to 60.1, demonstrating its potential for space-station visual monitoring. Full article

Background/Objectives: Spaceflight presents a combination of physical and psychosocial stressors that may impact biological aging and health. Understanding how spaceflight influences molecular aging processes is essential as commercial and professional space travel continue to expand. Methods: We analyzed publicly available DNA methylation data to evaluate longitudinal changes in 10 epigenetic aging biomarkers, 6 leukocyte proportion estimates, and 109 DNA methylation-derived protein scores in two astronauts participating in Axiom Space’s AX1 17-day low Earth orbit mission. We calculated mean values for all biomarkers across three timepoints: two weeks before spaceflight (T0), 24 h after spaceflight (T1), and three months after spaceflight (T2). Using the mean values, we next calculated the fold change from baseline for all biomarkers. Because the sample size precluded statistical testing, we identified the top 5% of absolute fold changes to highlight the largest shifts across candidate biomarkers. Results: Across epigenetic clocks, MiAge showed the greatest T0–T1 decrease (−4.26-fold), and DNAmFitAge showed the greatest T0–T2 increase (2.47-fold). NK cells exhibited the largest T0–T1 change, decreasing by 49% (−0.49-fold). B cells exhibited the largest T0–T2 change, decreasing by 11% (−0.11-fold). Proteins meeting a predefined top 5% fold change from baseline criterion at both T1 and T2, included BMP1, CLEC11A, CXCL11, FAP, and LTF. Enrichment analysis indicated involvement of serine-type endopeptidase activity, molecular function activator activity, and cell aggregation pathways. Conclusions: These findings suggest that spaceflight influences methylation-derived biomarkers of aging and immunity even in short-duration missions. These results, though exploratory, contribute to emerging efforts to characterize molecular resilience and vulnerability in human spaceflight. Full article

Background: The COVID-19 pandemic resulted in over 705 million infections and 7 million deaths, underscoring the importance of understanding disease behavior across diverse environments. As NASA, SpaceX, and ISRO prepare for more frequent missions, managing health risks for astronauts and space tourists is essential. Objective: This study reviews the literature on airborne infections in space, identifies research gaps, and establishes preparedness strategies for potential COVID-19 outbreaks during space missions. Methods: A systematic literature review was conducted to identify studies examining airborne infectious diseases in space. To compare these findings with Earth-based data, pathogen safety data sheets were used. A separate systematic review was conducted to explore similarities between COVID-19 and the identified airborne infectious diseases. A comparative approach was used to predict COVID-19’s potential behavior in microgravity. Existing guidelines for managing airborne diseases in space and on Earth were reviewed and compared to develop a set of preparedness recommendations for COVID-19 in space. Results: Nine airborne infectious diseases occurring in space were identified. Six tentative effects of COVID-19 in a microgravity environment were theorized in this study. We propose recommendations to improve current space travel health guidelines and address the identified risks. Conclusions: The results of this study will change the course of human space exploration by assisting in the protection of space travelers and guiding the development of new protocols that include comprehensive safety features. Full article

Spaceflight exposes astronauts to multiple environmental stressors that promote oxidative stress, including ionizing radiation, microgravity, circadian rhythm disruption, and psychological stress. These factors increase the production of reactive oxygen species (ROS) and disturb redox homeostasis, potentially affecting multiple physiological systems during long-duration missions. In addition to environmental challenges, nutritional factors may further influence oxidative balance in space. Space food systems rely on long-term storage and processing, which can lead to degradation of antioxidant nutrients and alterations in dietary composition. Furthermore, spaceflight conditions may modify eating behaviors and disrupt gut microbiome composition, both of which are closely linked to host redox regulation. This review examines current knowledge on oxidative stress during spaceflight and discusses how space food systems, dietary composition, and microbiome alterations interact with spaceflight stressors to influence redox homeostasis. Potential strategies to mitigate oxidative stress are also discussed, including preservation of antioxidant nutrients, optimization of dietary composition, reduction in pro-oxidant exposures, and microbiome-targeted approaches to support astronaut health during long-duration missions. Full article

Vascular remodeling driven by the phenotypic switching of vascular smooth muscle cells (VSMCs) poses a significant health risk to astronauts during long-duration spaceflight. While the morphological and molecular changes are well recognized, the underlying metabolic drivers and potential translational countermeasures remain elusive. To investigate the metabolic determinants of VSMCs phenotypic switching, human aortic smooth muscle cells (HASMCs) were subjected to cyclic mechanical stretch, an in vitro model offering indirect mechanistic insights into mechanical loading conditions relevant to spaceflight-associated hemodynamic alterations. An integrated approach combining quantitative proteomics, flux analysis (Seahorse), and functional assays (cell cycle, wound healing, transwell) was used to characterize the accompanying metabolic and phenotypic alterations. Molecular mechanisms were assessed using immunoprecipitation, protein crosslinking, and immunofluorescence. Mechanical stretch triggered a contractile-to-synthetic phenotypic switch in HASMCs, accompanied by a shift from oxidative phosphorylation to aerobic glycolysis. Pyruvate kinase M2 (PKM2) was identified as a central metabolic regulator of this process, its silencing reversed the pro-synthetic phenotype. Notably, lactate, a glycolytic product, was found to exert a self-limiting feedback signal. Exogenous lactate suppressed the synthetic switch in associated with increased PKM2 lactylation. Further analysis indicated that PKM2 lactylation was associated with enhanced stability of its active tetrameric conformation, which was associated with a metabolic shift toward oxidative phosphorylation and restored expression of contractile markers. Although specific lactylation sites on PKM2 were not identified in this study, and direct causality between lactylation and tetramerization remains to be established, these findings identify a previously unrecognized association. This study reveals a novel metabolic regulatory mechanism in which lactate correlates with the suppression of synthetic switching of VSMCs, linked to PKM2 lactylation and tetramer stabilization. The observed lactate-PKM2 axis represents a candidate metabolic node associated with VSMCs phenotype regulation and offers a potential therapeutic target for modulating vascular remodeling. Upon direct validation under relevant conditions in future studies, this mechanism may inform the development of novel therapeutic strategies for managing vascular adaptation during long-duration spaceflight and other aerospace-related physiological challenges. Full article

The rapid expansion of commercial human spaceflight is forcing a re-examination of how we decide who is “fit to fly” in space. For more than six decades, astronaut selection has been dominated by government programmes employing stringent medical and psychological criteria designed to minimise risk for small cohorts undertaking long-duration, high-consequence missions. Contemporary standards such as NASA-STD-3001 reflect this paradigm, treating astronauts as highly trained national assets expected to perform reliably under extreme physiological and psychological stress. In contrast, commercial operators aim to fly large numbers of spaceflight participants with highly heterogeneous medical and psychological profiles, within regulatory frameworks that emphasise informed consent and currently impose very limited prescriptive health requirements on passengers. This review examines the evolution and structure of traditional astronaut selection, outlines emerging approaches to screening and certifying commercial spaceflight customers, and explores the conceptual and practical gap between “selection” and “screening”. Particular attention is given to the increasing relevance of behavioural and psychological risk in short-duration but high-stress commercial missions, where acute responses, passenger–crew interaction, and behavioural variability can influence safety, especially in mixed-capability crews. Drawing on agency standards, psychological selection research, and recent proposals for commercial medical guidelines, this paper proposes a risk-informed, mission- and role-specific framework that adapts lessons from government astronaut corps to the needs of commercial spaceflight. We argue that future practice must balance safety, inclusion, and commercial viability through proportionate, evidence-based risk management, supported by systematic data collection across government and commercial flights. Full article

As humanity continues to strive for extraplanetary exploration, which is quickly gaining marked governmental and industrial support and recognition, there are still substantial detriments to astronaut health during long-duration spaceflight (i.e., muscle atrophy) that must be addressed. The effects of long-duration spaceflight on muscle architecture, morphology, and function have been well documented since the Apollo and Space Shuttle Programs. Countermeasures focused on resistance or aerobic training, such as the Advanced Resistive Exercise Device, Multi-modal Exercise Device, flywheel exercise, and aerobic exercise on a mounted treadmill and/or a cycle ergometer with vibration isolation system, have been assessed to combat the functional and mechanical losses in muscle while astronauts are in low Earth orbit. However, a lesser-understood countermeasure to muscle atrophy during spaceflight is neuromuscular electrical muscle stimulation (NMES). Although utilization in spaceflight is limited, ground-based research on NMES in diseased or injured populations demonstrates its effectiveness as a promoter of muscle anabolism and growth. The previous literature has suggested the use of electrical muscle stimulation as a low-effort modality of exercise for astronauts, which could effectively enhance astronaut health and contribute to mission success. The efficacy and mechanisms of action of using NMES to attenuate atrophy in astronauts will be discussed in this review. Full article

Microgravity during space travel induces significant regulatory changes in the body, posing health risks for astronauts, including alterations in cell morphology and cytoskeletal integrity. The Small Ubiquitin-like Modifier (SUMO) is crucial for cellular adaptation, regulating DNA repair, cytoskeletal dynamics, cell division, and protein turnover—all processes affected by microgravity. To determine the extent to which SUMO mediates the cellular response to microgravity stress, Saccharomyces cerevisiae cells were cultured under normal gravity and simulated microgravity (SMG) in rotating wall vessels. After 12 h of culture, we investigated changes in SUMO modified proteins and protein expression. We identified 347 SUMOylated proteins, 18 of which demonstrated a 50% change in abundance under SMG. Of 3773 proteins identified, protein expression for 34 proteins decreased and 8 increased by over 50% in SMG (p < 0.05). Differentially expressed proteins represented changes in cellular processes for DNA repair, cell division, histone modification, and cytoskeleton regulation. These findings underscore the pivotal role of SUMOylation in orchestrating cellular adaptation to the unique stress of microgravity, revealing potential targets for mitigating spaceflight-induced health risks. Full article

SCC is a standard indicator of udder inflammation, but it reflects only part of the broader physiological changes occurring in the mammary gland. This study aimed to evaluate associations between SCC, in-line milk traits, and blood biochemical markers in Holstein dairy cows. Based on SCC and California Mastitis Test (CMT) results, 59 cows (20–100 DIM) were divided into three groups: Group 1 (SCC < 200,000 cells/mL; n = 20), Group 2 (SCC 200,000–500,000 cells/mL; n = 19), and Group 3 (SCC > 500,000 cells/mL; n = 20). The Lely Astronaut^® A3 system was used to record milk parameters and behavioral data, while blood samples were collected for biochemical analysis. While there were negative relationships with milk yield (r = −0.266, p < 0.05) and creatinine (r = −0.291, p < 0.05), there was a significant positive correlation between SCC and milk electrical conductivity (EC) (r = 0.330, p < 0.05), gamma-glutamyl transferase (GGT) (r = 0.424, p < 0.001), and lactate dehydrogenase (LDH) (r = 0.285, p < 0.05). Potassium and chloride concentrations varied between groups, indicating slight electrolyte imbalances linked to higher SCC even though they remained within physiological bounds. Receiver operating characteristic (ROC) analysis further showed that milk EC (area under the curve (AUC) = 0.770) and blood potassium (AUC = 0.707) demonstrated the highest diagnostic accuracy for distinguishing healthy and mastitic cows. These results show that integrating SCC data with automated in-line monitoring and blood biochemical profiling can help identify novel complementary indicators for the detection of mastitis in dairy cows and offer a deeper understanding of udder health. Full article

The growing body of biomedical research reveals that many biological processes are governed by quantum physical principles, including the effects of weak magnetic fields (MFs) at or below geomagnetic strength. Given that life evolved within the geomagnetic field, its significant decrease—the hypomagnetic field (hypoMF)—may disrupt fundamental biological processes. This is particularly relevant for interplanetary missions, where astronauts will encounter prolonged hypoMF conditions alongside other spaceflight stressors. This mini-review synthesizes current knowledge on hypoMF effects, comparing terrestrial and extraterrestrial MF conditions and evaluating evidence from human studies. The initial database search identified 645 records. After most were excluded for various reasons, only 44 publications on the effects of MFs on the entire human body were included in the review. An effect of the hypoMF was reported in 10 of these studies and was absent in 4. Despite some methodological limitations in the available research, the evidence suggests that the human body is not indifferent to hypoMF exposure. We also discuss leading mechanistic molecular hypotheses—particularly the radical pair mechanism. Finally, we identify urgent research priorities to elucidate hypoMF’s biological role and develop countermeasures for future deep space exploration. Addressing these gaps is essential for safeguarding astronaut health and advancing magnetobiology as a frontier discipline in biophysics. Full article

Long-duration space missions expose astronauts to galactic cosmic radiation (GCR), a complex spectrum of high-charge, high-energy (HZE) ions that pose significant risks of chronic tissue injury. To model these effects, we examined intestinal outcomes in wild-type mice 5 months after low-dose (50 cGy) 33-ion mixed-field GCR simulation (GCRsim). GCRsim induced sustained DNA double-strand breaks (DSBs) and oxidative stress, as shown by elevated γH2AX foci and 4-HNE staining. Intestinal epithelial cells (IECs) exhibited pronounced senescence, marked by increased SA-β-gal activity, p16 upregulation, LaminB1 loss, and induction of senescence-associated secretory phenotype (SASP) cytokines (Cxcl10, IL-6, IL-1β, Icam1). GCRsim also elevated circulating LINE-1 DNA and reduced expression of DNA-degrading nucleases (DNase2, TREX1), indicating impaired extracellular DNA clearance. Targeted molecular study revealed persistent activation of the cGAS–STING pathway, with elevated cGAS, STING, pTBK1, pIKKα/β, and nuclear pIRF3, pIRF7, and p65, consistent with chronic innate immune signaling. Functionally, GCRsim altered nutrient absorption gene expression—upregulating glucose transporters (Slc2a2, Slc2a5, Slc5a1) and gut hormones (Cck, Gip), while downregulating cholesterol/fat transporters (Npc1, Npc1l1). Biochemical markers supported intestinal injury, with decreased serum citrulline and increased intestinal fatty acid-binding protein (I-FABP), indicating barrier compromise. Collectively, these findings demonstrate that GCRsim drives sustained intestinal dysfunction, highlighting the need for countermeasures to protect GI health during deep-space missions. Full article

Lunar dust remains one of the most critical unresolved challenges to long-duration lunar missions. Its sharp, abrasive, and electrostatically charged particles are easily inhaled and can penetrate deep into the lungs, reaching the bloodstream and the brain. Despite airlocks and HEPA filtration systems, dust will inevitably infiltrate lunar habitats and threaten astronaut health. We present a novel patent protected helmet design. This system uses a multilayered, synergistic mitigation approach combining mechanical and electrostatic defenses. The mechanical system delivers HEPA-filtered, ionized air across the user’s face, while the electrostatic barrier repels charged particles away from the respiratory zone. These two systems work together to prevent dust from entering the user’s breathing space. Designed for use inside lunar habitats, this helmet represents a potential solution to an unaddressed, life-threatening problem. It allows astronauts to eat, talk, and sleep while maintaining a protected respiratory zone and provides targeted inhalation-level protection in an environment where dust exposure is otherwise unavoidable. This concept is presented at Technology Readiness Level 2 (TRL 2) to prompt early engagement and feedback from the scientific and engineering communities. Full article

Spaceflight imposes unique physiological stressors that profoundly disrupt immune regulation, including impaired lymphocyte activation, latent viral reactivation, and chronic low-grade inflammation. While structured exercise is the cornerstone countermeasure for musculoskeletal and cardiovascular health, current protocols rarely integrate immune endpoints into their design. This review aims to synthesize current evidence on the immunological effects of exercise in spaceflight and propose a novel framework for immune-focused physical activity guidelines tailored to long-duration missions. Evidence indicates that exercise intensity and modality critically determine immune outcomes. Acute strenuous exercise may transiently suppress immunity via cortisol and reactive oxygen species pathways, whereas chronic moderate-to-vigorous training enhances immune surveillance, reduces systemic inflammation, and supports T-cell and NK-cell function. Exerkines such as IL-15, IL-7, and irisin emerge as central mediators of exercise-induced immunomodulation, with potential applications for spaceflight countermeasures. Incorporating immune health into exercise guidelines represents a necessary paradigm shift for astronaut care. A structured framework—emphasizing aerobic, resistance, and HIIT modalities; moderate-to-vigorous intensity; daily training; immune biomarker monitoring; and integration with nutrition and sleep—can enhance resilience against infection, viral reactivation, and cancer risk. Immune-focused countermeasures will be essential to safeguard astronaut health and ensure mission success on future deep-space expeditions. Full article