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"Weightlessness."
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Space survival guide
Imagine you're an astronaut living in space. What do you need to do to survive? Find out how a space suit protects you, what it's like to be weightless, and how it affects how you eat, walk, and talk.
Book
Long-term dry immersion: review and prospects
Dry immersion, which is a ground-based model of prolonged conditions of microgravity, is widely used in Russia but is less well known elsewhere. Dry immersion involves immersing the subject in thermoneutral water covered with an elastic waterproof fabric. As a result, the immersed subject, who is freely suspended in the water mass, remains dry. For a relatively short duration, the model can faithfully reproduce most physiological effects of actual microgravity, including centralization of body fluids, support unloading, and hypokinesia. Unlike bed rest, dry immersion provides a unique opportunity to study the physiological effects of the lack of a supporting structure for the body (a phenomenon we call ‘supportlessness’). In this review, we attempt to provide a detailed description of dry immersion. The main sections of the paper discuss the changes induced by long-term dry immersion in the neuromuscular and sensorimotor systems, fluid–electrolyte regulation, the cardiovascular system, metabolism, blood and immunity, respiration, and thermoregulation. The long-term effects of dry immersion are compared with those of bed rest and actual space flight. The actual and potential uses of dry immersion are discussed in the context of fundamental studies and applications for medical support during space flight and terrestrial health care.
Journal Article
Plummet
\"This. . .graphic novel opens with Mel, an ordinary young woman, inexplicably falling through an infinite expanse of sky. With the initial panic out of the way, she settles into her bizarre new existence: sleeping and relieving herself in midair, using her jacket to glide like a flying squirrel, and scavenging food and water from the mundane detritus and household objects and appliances plummeting around her. \"Do I just keep falling forever?\" she wonders, a question this graphic novel leaves, so to speak, up in the air.\"--Publisher's Weekly.
Book
Microgravity-Related Changes in Bone Density and Treatment Options: A Systematic Review
Space travelers are exposed to microgravity (µg), which induces enhanced bone loss compared to the age-related bone loss on Earth. Microgravity promotes an increased bone turnover, and this obstructs space exploration. This bone loss can be slowed down by exercise on treadmills or resistive apparatus. The objective of this systematic review is to provide a current overview of the state of the art of the field of bone loss in space and possible treatment options thereof. A total of 482 unique studies were searched through PubMed and Scopus, and 37 studies met the eligibility criteria. The studies showed that, despite increased bone formation during µg, the increase in bone resorption was greater. Different types of exercise and pharmacological treatments with bisphosphonates, RANKL antibody (receptor activator of nuclear factor κβ ligand antibody), proteasome inhibitor, pan-caspase inhibitor, and interleukin-6 monoclonal antibody decrease bone resorption and promote bone formation. Additionally, recombinant irisin, cell-free fat extract, cyclic mechanical stretch-treated bone mesenchymal stem cell-derived exosomes, and strontium-containing hydroxyapatite nanoparticles also show some positive effects on bone loss.
Journal Article
Hypogravity simulation using the Variable Gravity Suspension System: A technical report
Human movement has evolved within Earth's gravitational environment (1 g; −9.81 m s−2). Future human exploration of terrestrial bodies, including the Moon (0.17 g; −1.62 m s−2) and Mars (0.38 g; −3.71 m s−2), will require astronauts to live and work within reduced gravitational environments (hypogravity). Progressing understanding of the physiological and biomechanical implications of movement in hypogravity will play a key role in supporting the expansion of humanity to terrestrial bodies beyond Earth, within our solar system. Ground‐based hypogravity analogues that enable the study of human movement are pivotal to developing knowledge in this field. Whole‐body suspension can serve as a resource‐efficient and accessible hypogravity analogue, yet only a limited number of such analogues exist globally. This technical report introduces a new hypogravity analogue facility: the Variable Gravity Suspension System (VGSS). The report introduces the VGSS and its theoretical framework, which enables simulation of both micro‐ and hypo‐gravity, presents proof‐of‐concept data regarding its ability to simulate hypogravity, and demonstrates the ability of the VGSS to facilitate locomotive and jumping activities in simulated hypogravity. What is the central question of this study? This study introduces and demonstrates proof‐of‐concept for the Variable Gravity Suspension System (VGSS), a newly developed analogue for simulating hypogravity using head‐up tilt whole body suspension What is the main finding and its importance? Hypogravity between 0 and 0.2 g can be accurately simulated using the VGSS and allows users to perform movement in the sagittal plane, including locomotive and jumping activities.
Journal Article
Characterization of the random positioning machine as a microgravity simulator for biological applications
Simulated microgravity platforms provide essential tools for studying gravitational effects on biological systems under controlled laboratory conditions. The Random Positioning Machine (RPM) is among the most commonly used ground-based simulators, yet quantitative evaluations of its mechanical performance and biological effects remain limited. This study provides a comprehensive mechanical and biological characterization of an RPM device capable of operating in randomized, unidirectional, and single-axis clinostat modes. Angular velocity profiles were experimentally recorded using magneto-inertial measurement units mounted on the RPM frames. These data informed a computational model that simulated gravity vector dispersion and centrifugal acceleration across different operational configurations. Additionally, SH-SY5Y neuronal cells were exposed to simulated microgravity under each mode to evaluate cellular responses. The computational analysis demonstrated that all RPM modes effectively achieved simulated microgravity conditions, with time-averaged gravity values ranging from 10-2 to 10-3 g. Centrifugal accelerations remained below 0.08 g across all conditions. Biologically, SH-SY5Y cells exposed to simulated microgravity exhibited reduced confluency and increased α-synuclein inclusions in all RPM configurations, with milder effects observed in clinostat mode. The integration of experimental, computational, and biological analyses establishes a quantitative framework for assessing and optimizing RPM-based microgravity simulations. The findings confirm that both RPM and clinostat modes can reproduce key features of microgravity, while highlighting the role of motion characteristics in shaping biological responses. The proposed computational model represents a predictive tool to support the design and reproducibility of future ground-based microgravity studies.
Journal Article
The Emerging Role of Macrophages in Immune System Dysfunction under Real and Simulated Microgravity Conditions
In the process of exploring space, the astronaut’s body undergoes a series of physiological changes. At the level of cellular behavior, microgravity causes significant alterations, including bone loss, muscle atrophy, and cardiovascular deconditioning. At the level of gene expression, microgravity changes the expression of cytokines in many physiological processes, such as cell immunity, proliferation, and differentiation. At the level of signaling pathways, the mitogen-activated protein kinase (MAPK) signaling pathway participates in microgravity-induced immune malfunction. However, the mechanisms of these changes have not been fully elucidated. Recent studies suggest that the malfunction of macrophages is an important breakthrough for immune disorders in microgravity. As the first line of immune defense, macrophages play an essential role in maintaining homeostasis. They activate specific immune responses and participate in large numbers of physiological activities by presenting antigen and secreting cytokines. The purpose of this review is to summarize recent advances on the dysfunction of macrophages arisen from microgravity and to discuss the mechanisms of these abnormal responses. Hopefully, our work will contribute not only to the future exploration on the immune system in space, but also to the development of preventive and therapeutic drugs against the physiological consequences of spaceflight.
Journal Article
Remote Controlled Autonomous Microgravity Lab Platforms for Drug Research in Space
Research conducted in microgravity conditions has the potential to yield new therapeutics, as advances can be achieved in the absence of phenomena such as sedimentation, hydrostatic pressure and thermally-induced convection. The outcomes of such studies can significantly contribute to many scientific and technological fields, including drug discovery. This article reviews the existing traditional microgravity platforms as well as emerging ideas for enabling microgravity research focusing on SpacePharma’s innovative autonomous remote-controlled microgravity labs that can be launched to space aboard nanosatellites to perform drug research in orbit. The scientific literature is reviewed and examples of life science fields that have benefited from studies in microgravity conditions are given. These include the use of microgravity environment for chemical applications (protein crystallization, drug polymorphism, self-assembly of biomolecules), pharmaceutical studies (microencapsulation, drug delivery systems, behavior and stability of colloidal formulations, antibiotic drug resistance), and biological research, including accelerated models for aging, investigation of bacterial virulence , tissue engineering using organ-on-chips in space, enhanced stem cells proliferation and differentiation.
Journal Article
Hardware-independent control for partial gravity simulation using a 2-DOF robotic device
A variety of physiological changes in the human body have been observed to occur under the microgravity conditions of space. 3D clinostat devices capable of implementing time-averaged simulated microgravity (taSMG) have been widely used to predict these changes on Earth and to identify their underlying mechanisms. Recently, the concept of time-averaged simulated partial gravity (taSPG), which mimics the gravitational environments of the Moon (0.17 g) and Mars (0.38 g), has been proposed as an extension of taSMG, and clinostat control algorithms capable of implementing it have been developed. However, existing taSPG algorithms are dependent on specific hardware, limiting their versatility. Further, they are unable to generate taSPG levels exceeding 0.44 g. To address this limitation, we propose an improved control algorithm and validate it through both simulation and experiments. By applying an algorithm that does not depend on the characteristics of individual clinostat hardware, we confirmed the accurate implementation of taSPG up to 0.809 g. By adjusting the parameters, taSPG levels approaching 1 g can also be achieved. Notably, for taSPG in the range of 0.265 g to 0.635 g, the experimental values demonstrated refined accuracy with approximately 1% or less deviation from the simulation results.
Journal Article
Spaceflight and Ground-Based Microgravity Simulation Impact on Cognition and Brain Plasticity
Microgravity exposure during spaceflight has been linked to cognitive impairments, including deficits in attention, executive function, and spatial memory. Both space missions and ground-based analogs—such as head-down bed rest, dry immersion, and hindlimb unloading—consistently demonstrate that altered gravity disrupts brain structure and neural plasticity. Neuroimaging data reveal significant changes in brain morphology, functional connectivity, and cerebrospinal fluid dynamics. At the cellular level, simulated microgravity impairs synaptic plasticity, alters dendritic spine architecture, and compromises neurotransmitter release. These changes are accompanied by dysregulation of neuroendocrine signaling, decreased expression of neurotrophic factors, and activation of oxidative stress and neuroinflammatory pathways. Molecular and omics-level analyses further point to mitochondrial dysfunction and disruptions in key signaling cascades governing synaptic integrity, energy metabolism, and neuronal survival. Despite these advances, discrepancies across studies—due to differences in models, durations, and endpoints—limit mechanistic clarity and translational relevance. Human data remain scarce, emphasizing the need for standardized, longitudinal, and multimodal investigations. This review provides an integrated synthesis of current evidence on the cognitive and neurobiological effects of microgravity, spanning behavioral, structural, cellular, and molecular domains. By identifying consistent patterns and unresolved questions, we highlight critical targets for future research and the development of effective neuroprotective strategies for long-duration space missions.
Journal Article