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[Display omitted] Eutectic growth process is usually characterized by the simultaneous coupled growth of two different solids within one uniform liquid phase, while fluid dynamics normally predicts the equiaxed shrinkage for floating viscous droplets on freezing. Here a decoupling effect was induced by the microgravity and containerless states aboard space station, which led to the independent dendrite growth of two eutectic phases within extremely undercooled liquid Nb-Si refractory alloy. The confronting fluid flow pattern driven by polar heterogeneous nucleation was found to stimulate the elongated surface deformation of alloy droplet at a high dendrite growth velocity. [ABSTRACT FROM AUTHOR]

The exponential progress in the field of space science and technology has facilitated the prolonged habitation of astronauts in the space environment. However, the neurological and cognitive impairments of astronauts have become major factor that directly impede the successful completion of space missions. Studies have demonstrated that microgravity can diminish neuronal functions and cognitive abilities by altering the microenvironment of the brain (BME). Microglia, vital immune cells responsible for regulating the integrity of the blood-brain barrier, have been identified as the principal contributing elements to the neurological deterioration observed in microgravity conditions. The primary objective of this study was to provide an understanding of the molecular processes underlying the behavior of microglia under conditions of microgravity. Using a Random Positioning Machine (RPM) to simulate microgravity, our study found that microgravity reduces BV2 microglial cell viability, induces M1 polarization, and significantly increases late apoptosis. Transcriptome analysis revealed 142 differentially expressed genes related to microglial phenotype and inflammation, with qPCR validating selected DEGs. These results elucidate the molecular mechanisms of microglial behavior under microgravity, highlighting gene expression changes and cellular damage. This study provides a conceptual framework for comprehending the influence of microgravity on the neurological system, establishing countermeasures against functional damage to the nervous system caused by space flight, and serving as a reference for future deep space exploration and long-term manned space medical support. [Display omitted] • Simulated microgravity (SMG) inhibits the viability of BV2 cells. • SMG induces late apoptosis and M1 activation of BV2 cells. • SMG alters DEGs related neuroinflammation of BV2 cells by transcriptome sequencing. [ABSTRACT FROM AUTHOR]

We numerically investigate the effect on sloshing in microgravity of systems with passive, moving baffles whose motion is restricted by linear springs. The liquid is assumed to have physical properties similar to those of 5 cSt silicone oil while the baffle is made of aluminium. Two kinds of numerical models are developed depending on whether the allowed baffle motion is translational or rotational. Simulations show that moving baffles significantly improve sloshing mitigation compared to fixed baffles, with decreases of up to 48% in the decay time and 23% in the fluid kinetic energy following excitation by a certain pulse-like acceleration. In all configurations considered, there exists an optimal spring stiffness that minimises the kinetic energy or decay time. Frequency analysis reveals two peaks in the range of 0.1–2 Hz whose amplitudes vary as a function of spring stiffness, analogous to the behaviour of Tuned Mass Dampers (TMDs). The effectiveness of the moving baffle system is then assessed using a real microgravity perturbation measured during a reboosting manoeuvre of the International Space Station (ISS) and a significant reduction in decay time relative to the fixed baffle case is found: to 1.3 s from 4 s. • Moving baffles are investigated for sloshing reduction in microgravity. • Two configurations are analysed: allowing translational or rotational baffle motion. • Optimum spring stiffness minimises decay time and kinetic energy of the fluid system. • Microgravity perturbations are more effectively mitigated compared to fixed baffles. • A real microgravity scenario is tested with an ISS reboosting manoeuvre acceleration. [ABSTRACT FROM AUTHOR]

Additive manufacturing (AM) has significant utility for off-planet fabrication where dedicated infrastructure is severely limited, weight reduction and in situ resource utilization is desirable, and demands for complex systems are high. Direct ink writing (DIW) is a useful AM technique since it enables the deposition of a broad set of materials and the co-printing of multiple materials simultaneously. This allows for the fabrication of complex functional devices and systems in addition to structural objects. To evaluate this technique for space applications, this study characterized DIW in low gravity environments. Parabolic flights were used to simulate Martian, Lunar, and Micro gravity, and the effects that these 3 gravity regimes have on two critical print performance parameters, drooping and slumping, was evaluated using viscous paste inks deposited with an auger-driven extrusion head. In the drooping case, bridging structures were printed across gaps without support material, and the deformation was monitored. In the slumping case, a wall was printed through sequential layer deposition, and the vertical displacement of each layer under reduced gravity was explored. As expected, we found that a reduction in apparent gravity led to a decrease in the droop of a printed line, and as apparent gravitational acceleration is decreased its impact on the magnitude of drooping becomes less significant. For wall structures printed in simulated Lunar or Martian gravity regimes, the total structure height was found to be similar to that of a structure printed under Earth's gravitational conditions. In contrast, for prints performed in microgravity, it was found that slumping was significantly reduced and structure height was larger. These results provide experimental data to enable the design and optimization of appropriate structures and tool paths for printing objects using DIW for off-planet manufacturing. • Parabolic flights were used to evaluate direct ink write 3D printing under Lunar, Martian, and micro gravity regimes. • Structures made under these conditions show lower rates and degrees of deformation, allowing extended unsupported features. • A significant reduction in the slumping of multilayer prints occurs under microgravity conditions. [ABSTRACT FROM AUTHOR]

Two-phase flows under microgravity conditions play a crucial role in Space technology and science. Studying the behavior of dispersed droplets suspended in a gas flow and their influence on the characteristics of the carrier flow is the main task of computational modeling of turbulent two-phase flows. To understand the features and predict the behavior of such flows, along with experimental studies, it is necessary to develop mathematical models, which adequately describe all the basic physical and chemical processes in a gas-droplet environment at different scales. In this paper we obtain solutions for the problem of two droplets collision, using solutions for cumulative jets, and propose droplet collision outcome criterion. This research will focus on the process of two interacting droplets coalescence into one and coalescence with subsequent separation into two or more droplets. A semi-analytical method has been developed for application of the solution of the cumulative jet problem to the problem of droplet collision. A differential equation has been obtained that describes the following possible outcomes of droplet collision: coalescence and coalescence with subsequent separation. A criterion for determining the outcome of on-head droplet collision has been obtained. In accordance with the developed criterion, the number and size of formed droplets are obtained. The effect of collision on moving droplet evaporation in a heated atmosphere was regarded. • Solutions for the problem of two droplets collision and fragmentation are obtained. • A differential equation has been obtained that describes droplet coalescence or atomization. • A criterion for droplet fragmentation has been obtained. • The effect of collision on moving droplet evaporation in a heated atmosphere was regarded. [ABSTRACT FROM AUTHOR]

For many years, space human factors research has focused on the impact of microgravity on human physiology and the health risks astronauts face during space flights of various durations. Our review paper reveals that microgravity leads to both reversible and non-reversible effects on astronauts' oral health. In addition to oral health concerns, astronauts often experience muscle degeneration during space missions, which is closely tied to bone loss. Despite our knowledge of high bone resorption and rapid mineral and calcium loss in microgravity, the exact underlying mechanisms remain unclear. However, to fully understand these processes and develop effective strategies to counteract the consequences of microgravity, more research is needed. This includes a deeper exploration of how these molecules and other biomarkers work, identification of early mechanotransduction sensors, and a comprehensive understanding of the physiological effects of weightlessness. Current solutions primarily involve administering antioxidants, regular exercise, and appropriate nutrition. Additionally, innovative approaches such as experimental drug therapies using anti -myostatin antibodies and r-irisin have gained attention. Further large-scale, long-term studies are required to understand the effects of microgravity on the oral cavity and prevent its adverse consequences. • Impact of Microgravity on Dental Health: Discuss the physiological changes experienced by astronauts in microgravity environments, including fluid redistribution, decreased mechanical loading, and altered bone metabolism, and their implications for oral health. • Weight-Bearing vs. Non-Weight-Bearing Bones: Examines the relationship between microgravity and bone loss, with a focus on distinguishing its effects on weight-bearing and non-weight-bearing bones. • Comprehensive Impact Assessment: Calls for comprehensive research on how microgravity affects various bones in both animals and humans, including analyses of bone structure, density, and strength. • Bone Loss and Tooth Mobility: Examine how microgravity-induced bone loss affects the integrity of the jawbone, leading to increased tooth mobility and potential dental complications such as loosened crowns, dental implants, or even tooth loss. • Differential Recovery: Investigates how weight-bearing and non-weight-bearing bones recover following bone loss in microgravity conditions and the underlying mechanisms at play. • Addressing Inconsistencies: Highlights the need to resolve inconsistencies in existing literature regarding the influence of microgravity on osteogenic proliferation and differentiation. • Osteocytes and Osteoclasts in Microgravity: Emphasises the importance of understanding the roles of osteocytes and osteoclasts in microgravity-induced bone loss to identify potential therapeutic targets. [ABSTRACT FROM AUTHOR]

The crystallization of paramagnetic species in a magnetic field gradient under microgravity-like conditions is an area of interest for both fundamental and applied science. In this paper, a setup for the crystallization of paramagnetic species in the magnetic field up to 7 T generated by a superconducting magnet is described. The research includes calculations of the conditions necessary to compensate for the gravitational force for several types of paramagnetic substances using the magnetic field of superconducting magnets (4.7 T, 7 T, 9.4 T, and 16.4 T). Additionally, for the first time, the crystallization of copper sulfate and cobalt sulfate, as well as a mixture of copper sulfate and cobalt sulfate under gravitational force compensation in a superconducting magnet, was performed. This paper experimentally demonstrates the feasibility of growing paramagnetic crystals within the volume of a test tube on the example of copper and cobalt sulfate crystals. A comparison of crystals grown from the solution of a mixture of copper and cobalt sulfates under the same conditions, with and without the presence of a magnetic field, showed changes in both the number and size of crystals. [ABSTRACT FROM AUTHOR]

Background: Microgravity, a condition experienced in a spatial environment, poses unique challenges to the skeletal system, particularly in juvenile organisms. This study aimed to investigate alterations in bone biomechanics of juvenile mice due to unloading – that simulates microgravity in the laboratory—and the effects of a bone-loading intervention. We compared bone compositional and mechanical properties between 21-six-week-old C57Bl/6 from a control group (wild type) and a group that underwent a tail-suspension unloading protocol to mimic microgravity (MG). The second group (MG) experienced additional in vivo loading protocol (MG + LDG) on the right hind leg, where dynamic compressive loading was applied to the right knee using a custom-built loading device. Results: Our results show that after two weeks, we successfully induced bone alterations by (i) decreasing the energy dissipated before fracture and (ii) decreasing the yield and maximum stress. In addition, we showed that Mineral to matrix component [ν1PO4/Amide I], Carbonate to Amide [CO3/Amide I], and Crystallinity [1/FWHM(ν1PO4)] are strongly linked in physiological bone but not in microgravity even after loading intervention. While Crystallinity is very sensitive to bone deformation (strain) alterations coming from simulated microgravity, we show that Carbonate to Amide [CO3/Amide I] – a common marker of turnover rate/remodeling activity—is a specific predictor of bone deformation for bone after simulated microgravity. Our results also invalidate the current parameters of the loading intervention to prevent bone alterations entirely in juvenile mice. Conclusions: Our study successfully induced bone alterations in juvenile mice by using an unloading protocol to simulate microgravity, and we provided a new Raman Spectroscopy (RS) dataset of juvenile mice that contributes to the prediction of cortical bone mechanical properties, where the degree of interrelationship for RS data for physiological bone is improved compared to the most recent evidence. [ABSTRACT FROM AUTHOR]

In this paper, a new fractal nerve impulses modeling is successfully described via the Yang's local fractional derivative in a microgravity space, and its approximate analytical solution is obtained by a new Adomian decomposition method. The efficiency and accuracy analysis of the proposed method is elucidated according to the graphs. The result shows that our method is excellent and accurate in dealing with Local fractional differential equations. [ABSTRACT FROM AUTHOR]

During the ∼22 s lasting free fall phase in an aircraft flying a parabola, the aboard installed electromagnetic levitation facility "TEMPUS" is used to investigate contactless and undisturbed of gravity induced convection thermophysical properties and microstructure formations of hot and highly reactive metal or semiconductor melts. The completely contactless handling and measurement of a liquid by the levitation technique keeps the melt free of contamination and enables the extension of the accessible sample temperature range far into the undercooled liquid state below the melting point. Additionally, the state of reduced weight during parabolic flights allows us to considerably decrease the strongly disturbing electromagnetic levitation forces acting in ground-based facilities on the suspended liquids. The present paper explains in detail the basic principle and the technical realization of the TEMPUS levitation facility and its attached measurement devices. Furthermore, it presents some typical experiments performed in TEMPUS, which also show the advantages resulting from the combination of reduced weight, electromagnetic levitation, and contactless measurement techniques. The control and data recording, as well as the planning, preparation, and operation of the TEMPUS experiments within the parabolic flight campaign, are another aspect outlined in the following. [ABSTRACT FROM AUTHOR]

Heavy metals are one of the most dangerous environmental pollutions, and their elimination is one of the health system's priorities. Microorganisms have been introduced as a safe absorber of such pollution and this ability is related to the characteristics of their surface layers. There are reports about some bacteria's increment of cell envelope thickness in space conditions. Therefore, this study investigated SMG effect on heavy metals biosorption using Saccharomyces (S.) cerevisiae. Furthermore, the stability of complex, isotherm, and kinetic absorption models has been investigated. The results showed that the SMG positively affected the biosorption of mercury (Hg) 97% and lead (Pb) 72.5% by S. cerevisiae. In contrast, it did not affect cadmium (Cd) and arsenic (As) biosorption. In gastrointestinal conditions, Hg, Cd, and As‐yeast complexes were stable, and their biosorption increased. In the case of the Pb‐yeast complex, in simulated gastric exposure, the binding decreased at first but increased again in simulated intestinal exposure in both SMG and normal gravity (NG). The metals' biosorption by yeast followed the pseudo‐second‐order kinetic and the Langmuir isotherm models for all metals (As) matched with Langmuir and Freundlich. The current research results demonstrate that microgravity provides desirable conditions for heavy metal biosorption by S. cerevisiae. Furthermore, the biosorbent–heavy metal complex remains stable after simulated gastrointestinal conditions. Altogether, the results of this study could be considered in detoxifying food and beverage industries and maintaining astronauts' health. [ABSTRACT FROM AUTHOR]

Long-term spaceflight is known to induce disruptions in circadian rhythms, which are driven by a central pacemaker located in the suprachiasmatic nucleus (SCN) of the hypothalamus, but the underlying molecular mechanisms remain unclear. Here, we developed a rat model that simulated microgravity and isolation environments through tail suspension and isolation (TSI). We found that the TSI environment imposed circadian disruptions to the core body temperature, heart rate, and locomotor-activity rhythms of rats, especially in the amplitude of these rhythms. In TSI model rats' SCNs, the core circadian gene NR1D1 showed higher protein but not mRNA levels along with decreased BMAL1 levels, which indicated that NR1D1 could be regulated through post-translational regulation. The autophagosome marker LC3 could directly bind to NR1D1 via the LC3-interacting region (LIR) motifs and induce the degradation of NR1D1 in a mitophagy-dependent manner. Defects in mitophagy led to the reversal of NR1D1 degradation, thereby suppressing the expression of BMAL1. Mitophagy deficiency and subsequent mitochondrial dysfunction were observed in the SCN of TSI models. Urolithin A (UA), a mitophagy activator, demonstrated an ability to enhance the amplitude of core body temperature, heart rate, and locomotor-activity rhythms by prompting mitophagy induction to degrade NR1D1. Cumulatively, our results demonstrate that mitophagy exerts circadian control by regulating NR1D1 degradation, revealing mitophagy as a potential target for long-term spaceflight as well as diseases with SCN circadian disruption. [ABSTRACT FROM AUTHOR]

In-space manufacturing especially for external satellite structures has a huge potential to increase the packaging density of a satellite in launch configuration and enables large structures for advanced mission requirements. However, the processes and materials do have to withstand the harsh environmental conditions in space. These conditions have immediate effects on the manufacturing process as well as long-term effects on the structure manufactured in orbit. The experiments presented here are based on a photopolymer extrusion process by UV-radiation curing that is intended to be used as an in-space manufacturing technology. In order to understand the influence of reduced atmospheric pressure and microgravity on the process, we demonstrated the successful extrusion and curing of rod-shaped elements during a sounding rocket flight. Simultaneously, the same experiment was performed on the ground under normal gravity and ambient pressure. By comparing both groups of specimens, it was shown that the morphological artifacts and geometric deviations are more significant for the specimens manufactured during flight. This evaluation was performed by visual inspection, by comparison of the laser-scanned specimens with a reference model and by measuring and comparing the mass, length and diameter of the specimens. On a microscopic level, conducted by computer tomography, no influence of the reduced atmospheric pressure on the extrusion of the liquid photopolymer can be recognized as this was probably not low enough at the altitude reached by the rocket. As a result of this article, measures are proposed to avoid the morphological artifacts observed during the experiments and thus achieve higher accuracy and a resilient in-space manufacturing process. • Demonstration of Photopolymer Extrusion process under microgravity and vacuum. • Artifacts were identified for the specimen manufactured under microgravity and vacuum. • Bubbles were identified for the vacuum-exposed specimen because of not degassed resin. • The Microgravity environment showed no major influence on the specimen. [ABSTRACT FROM AUTHOR]

Phase change materials (PCMs) are an effective medium for thermal management of avionics because of their ability to absorb, store, and release high heat loads while operating within narrow temperature range in confined spaces. Despite hosting several benefits, PCM systems suffer from low thermal conductivity issue. Strategically placed fins in a volume filled with PCM has the potential to significantly improve the transient thermal performance of PCMs by improving the overall thermal conductivity and providing enhanced heat transfer surface area. Furthermore, avionics can be subjected to varying gravity conditions during flight that can have significant influence on the overall thermal performance of PCMs. This emphasizes the need to characterize the PCM performance under various gravity conditions that can impart different buoyancy induced effects in a confined system. To this end, numerical investigation to study the melting characteristics of PCM-fin configuration subjected to three different gravity conditions, i.e., (a) microgravity, (b) terrestrial gravity, and (c) hypergravity, is conducted. The influence of these three conditions on the performance of PCM-fin combination configuration is investigated and finally the temperature field, melt fraction, and melting time is reported. The performance of PCM-fin system is compared with the corresponding PCM-only configuration to highlight the benefits of adding fins under each investigated gravity condition. [ABSTRACT FROM AUTHOR]

Microgravity is one of the main stressors that astronauts are exposed to during space missions. This condition has been linked to many disorders, including those that feature dysfunctional immune homeostasis and inflammatory damage. Over the past 30 years, a significant body of work has been gathered connecting weightlessness—either authentic or simulated—to an inefficient reaction to pathogens, dysfunctional production of cytokines and impaired survival of immune cells. These processes are also orchestrated by a plethora of bioactive lipids, produced by virtually all cells involved in immune events, which control the induction, magnitude, outcome, compartmentalization and trafficking of immunocytes during the response to injury. Despite their crucial importance in inflammation and its modulation, however, data concerning the role of bioactive lipids in microgravity-induced immune dysfunctions are surprisingly scarce, both in quantity and in variety, and the vast majority of it focuses on two lipid classes, namely eicosanoids and endocannabinoids. The present review aims to outline the accumulated knowledge addressing the effects elicited by microgravity—both simulated and authentic—on the metabolism and signaling of these two prominent lipid groups in the context of immune and inflammatory homeostasis. [ABSTRACT FROM AUTHOR]

Aims Elucidating the impacts of long-term spaceflight on cardiovascular health is urgently needed in face of the rapid development of human space exploration. Recent reports including the NASA Twins Study on vascular deconditioning and aging of astronauts in spaceflight are controversial. The aims of this study were to elucidate whether long-term microgravity promotes vascular aging and the underlying mechanisms. Methods and results Hindlimb unloading (HU) by tail suspension was used to simulate microgravity in rats and mice. The dynamic changes of carotid stiffness in rats during 8 weeks of HU were determined. Simulated microgravity led to carotid artery aging-like changes as evidenced by increased stiffness, thickness, fibrosis, and elevated senescence biomarkers in the HU rats. Specific deletion of the mechanotransducer Piezo1 in vascular smooth muscles significantly blunted these aging-like changes in mice. Mechanistically, mechanical stretch-induced activation of Piezo1 elevated microRNA-582-5p in vascular smooth muscle cells, with resultant enhanced synthetic cell phenotype and increased collagen deposition via PTEN/PI3K/Akt signalling. Importantly, inhibition of miRNA-582-5p alleviated carotid fibrosis and stiffness not only in HU rats but also in aged rats. Conclusions Long-term simulated microgravity induces carotid aging-like changes via the mechanotransducer Piezo1-initiated and miRNA-mediated mechanism. [ABSTRACT FROM AUTHOR]

Mars is the next destination for further exploration and the hypothetical establishment of humanity's frontier. However, the planet offers very harsh environmental conditions particularly the very cold temperature in the Martian environment. Knowing that the sulphur-based construction material is perceived as one of the ideal Martian construction materials based on the identified abundant source of sulphur on Mars, its behaviour when subjected to the very cold Martian temperature is yet to be fully clarified. Therefore, this study intends to investigate the behaviour of the Martian sulphur-based construction material subjected to the simulated very cold Martian temperature whilst being compared with the simulated hot Martian temperature. Two mixture compositions of 50/50 and 60/40 comprising of sulphur and Mojave Mars simulant 1 (MMS-1) respectively were fabricated in this study characterising the simulated Martian temperature. The workability at 50 % and 60 % sulphur content was initially investigated. Subsequently, the overall mechanical properties characterising the sulphur content and simulated Martian temperature were investigated via unconfined compression, three-point bending and tensile splitting tests. Necessary factors that influence the overall mechanical properties including the internal structure and microstructural characteristics were also performed via ultrasonic pulse velocity (UPV) and scanning electron microscopy (SEM) respectively. X-ray diffraction (XRD) was also conducted to identify the chemical composition of the end product. The comparisons between this study and other previous related studies within the state-of-the-art Martian sulphur-based construction materials were also outlined. Prospects for future construction on Mars are also presented. It was found that the 60 % sulphur content exhibited higher workability due to the high amount of unreactive sulphur. The 50 % sulphur content recorded the optimal overall mechanical properties under the simulated hot and very cold Martian temperatures. The simulated very cold Martian temperature triggered non-uniform interparticle distribution and larger cavities thus dramatically reducing its overall strength and triggering higher volumetric inconsistency. The very brittle nature of unreactive crystallised sulphur binder at excessive thickness particularly at 60 % sulphur content in between filler particles also triggered volumetric inconsistency which further worsened at the simulated very cold Martian temperature. The iron sulphate hydrate found was almost in agreement with the related works and another new compound, potassium calcium magnesium sulphate was identified as well. The overall mechanical properties are comparable with the other previous related studies and the residual strength when subjected to the simulated very cold Martian temperature remains adequate in the Martian environment of low gravity. The 60 % sulphur content is suggested for structural elements built internally whereas the 50 % sulphur content demonstrated a high potential in adapting to the harsh Martian environmental conditions. The findings of this study hoped to act as the initial outlook on how such Martian sulphur-based construction material would react upon fabrication on Mars. • The mechanical properties at distinct Martian temperatures are presented. • The chemical composition of Martian sulphur-based construction material is defined. • The microstructure is altered at the very cold Martian temperature. • The optimal sulphur content of 50 % is recorded for both Martian temperatures. [ABSTRACT FROM AUTHOR]

Musical expression is a characteristic of humanity on Earth. This paper highlights the historical relationship between music and spaceflight, including its use in the representation of space, and its role in space culture. The paper documents circa 57 musical instruments: from a miniaturized harmonica to a 1.5 m Digeridoo that are known to have been taken into space – usually as part of a crew members personal allowance. Due to mass and volume restrictions numerous classical and ethnographic instruments have been 'spaceflight-adapted', in addition to the use of digital technologies for personal musical pleasure and public relations. Furthermore, it charts how access to personalised music playlists and shared musical experiences have been deemed to be vital by crew, promoting individual wellbeing including a connection to home, to each other and playing a part in the marking of success, and tragedy. The value of music making in space is briefly described leading to the proposition that as humanity ventures with greater regularity to Low Earth Orbit and beyond, consideration of how music can be effectively utilised to support individual and crew wellbeing, whilst contributing to the cannon of human artistic expression is warranted. • Music is a characteristic of humanity and social connection. • Circa 57 musical instruments have been taken into space. • Numerous instruments have been 'spaceflight-adapted'. • Personalised music playlists are deemed critical by crew to link to 'home'. • Music expression warrants consideration for missions beyond Low Earth Orbit. [ABSTRACT FROM AUTHOR]

Advancing the precision of low-gravity liquid propellant mass gauging is a roadmap challenge for NASA and a significant obstacle to expanding human presence in space. We report flight test data for an implementation of a low-gravity liquid propellant mass gauging technology that is both non-invasive and propellant agnostic. The TRIO payload experiment flew twice on the Blue Origin New Shepard suborbital rocket and validated computational models of liquid distribution in microgravity at three different fill levels. The Propellant Refueling and On-orbit Transfer Operations (PROTO) payload experiment also flew twice on New Shepard and acquired mass gauging data before, during, and after a tank drain and fill that simulated in-space propellant transfers. Propellant volume estimates were derived at 1 Hz using the Modal Propellant Gauging (MPG) system. Analytical, semi-empirical, and finite element (FE) model results for predicted mode frequencies are compared to flight data for mode frequencies across a range of fill levels during the simulated propellant transfer. Flight (0-g), ground (1-g) and FEM mode frequencies for both 0- and 1-g are well-predicted by the semi-empirical models for frequency dependence on tank fill level. • Modal Propellant Gauging (MPG) is a non-invasive and propellant agnostic liquid mass gauging technology. • Demonstrated high-accuracy low-gravity mass gauge during liquid transfer between two tanks. • Added mass effect shifts modal frequencies in predictable ways. • Modal Peak Tracking is capable of identifying liquid mass effects in fluid-loaded tanks. [ABSTRACT FROM AUTHOR]

The axial deployment force is an indispensable parameter of a lanyard-deployed coilable mast, which reflects its load capacity in practical applications. However, research on the axial deployment force in the literature is very limited, and there are no mature numerical methods to determine this parameter in the design stage of coilable masts. In this paper, a numerical method for determining the axial deployment force of a lanyard-deployed coilable mast in the local coil mode is presented. Through this method, the designer can quickly obtain the estimated value of the axial deployment force in the design stage, which is convenient for the quantitative design of parameters. To verify the correctness of the proposed method, a dynamic simulation of the coilable mast is carried out, and a microgravity test is performed. The comparison results show that the error between the numerical method and the simulation and experimental results is less than 5%, which proves the correctness of the proposed method. In addition, the coilable mast studied in this paper has been verified by an actual microsatellite deployment in orbit. [ABSTRACT FROM AUTHOR]

Gravity and mechanical forces cause important alterations in the human skeletal system, as demonstrated by space flights. Innovative animal models like zebrafish embryos and medaka have been introduced to study bone response in ground-based microgravity simulators. We used, for the first time, adult zebrafish in simulated microgravity, with a random positioning machine (RPM) to study bone remodeling in the scales. To evaluate the effects of microgravity on bone remodeling in adult bone tissue, we exposed adult zebrafish to microgravity for 14 days using RPM and we evaluated bone remodeling on explanted scales. Our data highlight bone resorption in scales in simulated microgravity fish but also in the fish exposed, in normal gravity, to the vibrations produced by the RPM. The osteoclast activation in both rotating and non-rotating samples suggest that prolonged vibrations exposure leads to bone resorption in the scales tissue. Stress levels in these fish were normal, as demonstrated by blood cortisol quantification. In conclusion, vibrational mechanical stress induced bone resorption in adult fish scales. Moreover, adult fish as an animal model for microgravity studies remains controversial since fish usually live in weightless conditions because of the buoyant force from water and do not constantly need to support their bodies against gravity. [ABSTRACT FROM AUTHOR]

Maintaining an optimal leaf and stem orientation to yield a maximum photosynthetic output is accomplished by terrestrial plants using sophisticated mechanisms to balance their orientation relative to the Earth's gravity vector and the direction of sunlight. Knowledge of the signal transduction chains of both gravity and light perception and how they influence each other is essential for understanding plant development on Earth and plant cultivation in space environments. However, in situ analyses of cellular signal transduction processes in weightlessness, such as live cell imaging of signaling molecules using confocal fluorescence microscopy, require an adapted experimental setup that meets the special requirements of a microgravity environment. In addition, investigations under prolonged microgravity conditions require extensive resources, are rarely accessible, and do not allow for immediate sample preparation for the actual microscopic analysis. Therefore, supply concepts are needed that ensure both the viability of the contained plants over a longer period of time and an unhindered microscopic analysis in microgravity. Here, we present a customized supply unit specifically designed to study gravity-induced Ca2+ mobilization in roots of Arabidopsis thaliana. The unit can be employed for ground-based experiments, in parabolic flights, on sounding rockets, and probably also aboard the International Space Station. [ABSTRACT FROM AUTHOR]

In this work, the quasinormal mode, greybody factors, and absorption cross section of de Sitter Reissner‐Nordström black hole surrounded by quintessence field in Rastall gravity are studied. The violation of energy‐momentum conservation has a non‐linear effect on the quasinormal modes. With an increase in the black hole charge, both real parts of quasinormal modes i.e. oscillation frequency of ring‐down Gravitational Waves (GWs) and damping or decay rate of GWs increase non‐linearly. A similar observation is made for the black hole structural parameter also, however in this case the variation is almost linear. The remnant mass of a black hole depends on different physical parameters of a black hole. In the case of greybody factors also, both parameters have similar impacts are observed. With an increase in these parameters, greybody factors decrease. Moreover, the null geodesics and the impact of Rastall gravity on the light trajectory are also investigated. Our study suggests that the presence of a surrounding quintessence field may shadow the existence of black hole charges in such black hole configurations. [ABSTRACT FROM AUTHOR]

The bone lacunar-canalicular system (LCS) is a unique complex 3D microscopic tubular network structure within the osteon that contains interstitial fluid flow to ensure the efficient transport of signaling molecules, nutrients, and wastes to guarantee the normal physiological activities of bone tissue. The mass transfer laws in the LCS under microgravity and hypergravity are still unclear. In this paper, a multi-scale 3D osteon model was established to mimic the cortical osteon, and a finite element method was used to numerically analyze the mass transfer in the LCS under hypergravity, normal gravity and microgravity and combined with high-intensity exercise conditions. It was shown that hypergravity promoted mass transfer in the LCS to the deep lacunae, and the number of particles in lacunae increased more significantly from normal gravity to hypergravity the further away from the Haversian canal. The microgravity environment inhibited particles transport in the LCS to deep lacunae. Under normal gravity and microgravity, the number of particles in lacunae increased greatly when doing high-intensity exercise compared to stationary standing. This paper presents the first simulation of mass transfer within the LCS with different gravity fields combined with high-intensity exercise using the finite element method. The research suggested that hypergravity can greatly promote mass transfer in the LCS to deep lacunae, and microgravity strongly inhibited this mass transfer; high-intensity exercise increased the mass transfer rate in the LCS. This study provided a new strategy to combat and treat microgravity-induced osteoporosis. [ABSTRACT FROM AUTHOR]

In order to improve the accuracy of gravity anomaly data processing, this study utilizes multi-scale surface fitting techniques (MSSF) to separate the Bouguer gravity field into residual gravity fields and regional gravity fields at different depths. By sequentially stripping away layers, the residual gravity anomalies of the target layer are obtained as the data basis for subsequent gravity interpretation. This study selects appropriate parameters and establishes different lithology forward modeling templates based on actual geological data in the study area. The method is verified to accurately separate gravity anomalies generated by different density bodies, with accurate anomaly locations, complete shapes, and clear boundaries. It can also serve as a quantitative template for rock properties and provide theoretical references for practical cases. Additionally, the method exhibits high noise resistance, resolution, and accuracy. The practical application of the method is validated through microgravity monitoring data in carbonate reservoirs in western China and time-shifted microgravity monitoring data in tight sandstone reservoirs. The results demonstrate that the obtained residual gravity anomaly data of the target layer can effectively reflect the distribution of reservoir fluids. [ABSTRACT FROM AUTHOR]

This study presents the design and implementation of a low-speed intrusion experiment under microgravity, with a strong motivation to support the pre-research of the Chinese asteroid exploration mission. In the experiment apparatus, we reconstructed an effective gravity of 10 - 2 g in a free-falling capsule in the drop tower. The simulant of regolith particles is processed using natural basalt and sorted using layered screens. The irregular shapes of the particles are retained to mimic the realistic regolith. A detailed description of the experimental system components and the full-cycle procedure is first presented, which gives 3.6 s of microgravity time for each trial. Repeatable controlled experiments are performed to characterize the dynamical responses of the simulant particles under centimeter-per second intrusion. The results reveal diverse responses that depend on different variables, and the mechanism of different responses is discussed based on theories of granular mechanics. This experimental study is expected to improve our understanding of the contact mechanics of regolith material, which will facilitate the operation design of future asteroid missions. [ABSTRACT FROM AUTHOR]

Microgravity is one of the most common causes counting for the bone loss. Mesenchymal stem cells (MSCs) contribute greatly to the differentiation and function of bone related cells. The development of novel MSCs biomarkers is critical for implementing effective therapies for microgravity induced bone loss. We aimed to find the new molecules involved in the differentiation and function of MSCs in mouse simulated microgravity model. We found CD226 was preferentially expressed on a subset of MSCs. Simulation of microgravity treatment significantly increased the proportion of CD226+Lin-CD117-Sca1+ MSCs. The CD226+ MSCs produced higher IL- 6, M-CSF, RANKL and lower CD200 expression, and promoted osteoclast differentiation. This study provides pivotal information to understand the role of CD226 in MSCs, and inspires new ideas for prevention of bone loss related diseases. [ABSTRACT FROM AUTHOR]

Background: Cells are sensitive to changes in gravity, especially the cytoskeletal structures that determine cell morphology. The aim of this study was to assess the effects of simulated microgravity (SMG) on 3T3 cell morphology, as demonstrated by a characterization of the morphology of cells and nuclei, alterations of microfilaments and microtubules, and changes in cycle progression. Methods: 3T3 cells underwent induced SMG for 72 h with Gravite®, while the control group was under 1G. Fluorescent staining was applied to estimate the morphology of cells and nuclei and the cytoskeleton distribution of 3T3 cells. Cell cycle progression was assessed by using the cell cycle app of the Cytell microscope, and Western blot was conducted to determine the expression of the major structural proteins and main cell cycle regulators. Results: The results show that SMG led to decreased nuclear intensity, nuclear area, and nuclear shape and increased cell diameter in 3T3 cells. The 3T3 cells in the SMG group appeared to have a flat form and diminished microvillus formation, while cells in the control group displayed an apical shape and abundant microvilli. The 3T3 cells under SMG exhibited microtubule distribution surrounding the nucleus, compared to the perinuclear accumulation in control cells. Irregular forms of the contractile ring and polar spindle were observed in 3T3 cells under SMG. The changes in cytoskeleton structure were caused by alterations in the expression of major cytoskeletal proteins, including β-actin and α-tubulin 3. Moreover, SMG induced 3T3 cells into the arrest phase by reducing main cell cycle related genes, which also affected the formation of cytoskeleton structures such as microfilaments and microtubules. Conclusions: These results reveal that SMG generated morphological changes in 3T3 cells by remodeling the cytoskeleton structure and downregulating major structural proteins and cell cycle regulators. [ABSTRACT FROM AUTHOR]

The research on particle size classification in lunar microgravity has gradually attracted the attention of scholars. Based on the discrete element method (DEM), this work proposes a double-layer auxiliary screening vibrating screen in the form of intermediate feeding, and takes the screening efficiency and screening time as the evaluation indicators. Firstly, the Helmholtz-Maxwell coil is used to simulate the force of particles under lunar microgravity, which verifies the reliability of the numerical simulation of particles under lunar microgravity based on the discrete element method. Then, the influence of the parameters of each screen on the comprehensive performance of screening was analyzed by a single-factor experiment. Finally, based on the BP (Back Propagation) neural network optimized by genetic algorithm, the evaluation model of screen parameters and screen performance is established, and the multi-objective genetic algorithm is used to optimize the screen parameters combination scheme with excellent performance. An efficient comprehensive model of screening is provided to improve the screening performance and the design of the screen machine under lunar microgravity. [ABSTRACT FROM AUTHOR]

Advances in hybrid surfaces have revealed interesting opportunities for multiphase flow control under microgravity, as the surface tension force is dominant in this condition. However, a comprehensive investigation of bubble generation rates and slug flow parameters remains challenging. This research integrates hybrid wettability and modified dynamic contact angle models to address this important knowledge gap. Using the computational capabilities of the IsoAdvector multiphase method, we performed detailed simulations of complex multiphase flow scenarios with the OpenFOAM package. We then validated these simulation results through rigorous comparison with available experimental data, thereby strengthening the accuracy and reliability of our numerical simulations. Our comprehensive research demonstrates the profound effect of altering contact angle distribution patterns on several critical parameters. These results highlight the precise control that can be achieved through the strategic manipulation of these patterns, offering the possibility of adjusting factors such as bubble production rate, slug length, bubble diameter, the relationship of flow residence to bubble movement, bubble movement speed in the channel, and pressure drop. Interestingly, altering these patterns can also induce asymmetric behavior in bubbles under microgravity conditions, a phenomenon that has significant implications for various applications. Such insights are crucial for fields such as heat transfer in energy systems, reaction mechanisms in chemical processes, multiphase flow control in petrochemical industries, fluid dynamics in aerospace engineering, and cooling mechanisms in electronic devices. With the ability to modulate these fundamental parameters, we gain valuable insights into the design and optimization of microchannel systems. Consequently, this research presents a more efficient and innovative approach to multiphase flow control, promising improved operational performance, and efficiency in various engineering applications. [ABSTRACT FROM AUTHOR]

Spacecraft cabin atmosphere revitalization, more specifically CO 2 removal, is a key technology to pursue long-duration, crewed space missions, such as the ones to the Moon and Mars. The ISS currently uses the Carbon Dioxide Removal Assembly (CDRA) as the primary system that employs solid sorbent (zeolite) to remove CO 2 from cabin air. However, CDRA cannot meet high reliability and low maintenance requirements. Liquid sorbents may be used as an alternative to solid sorbents and are estimated to attain 65 % less power, weight, and volume than solid based CO 2 scrubbers. Liquid amines (liquid sorbent) are currently being researched by NASA for CO 2 capture, however their implementation for space applications depends on an effective gas-liquid separation method under microgravity conditions. The Vortex Phase Separator (VPS) offers a new approach for a liquid amine CO 2 removal system, and initial investigation of the prototype VPS system demonstrated up to 90.3 % CO 2 removal from a humid CO 2 stream at 1.47 l/min flow rate. Tests were conducted to determine the CO 2 removal efficiency considering several operating parameters, including the liquid amine flow rate, initial fill (charge) level, and temperature; CO 2 flow rate; extended-time operation; and CO 2 -amine pre-mixing length. Results provided key insights on design, operation, and performance aspects of a subscale system, and demonstrated the feasibility of the microgravity VPS for liquid amine CO 2 removal system as an alternative, novel spacecraft air revitalization approach. • A microgravity Vortex Phase Separator (VPS) prototype is investigated. • VPS acts as direct contact heat and mass exchanger, and liquid-vapor phase separator. • VPS aims to use liquid amine to absorb CO 2 for spacecraft air revitalization. • Data demonstrated up to 90.3 % CO 2 removal from a CO 2 stream at 1.46 l/min flow rate. • Results from parametric tests suggest VPS-based CO 2 removal is a promising approach. [ABSTRACT FROM AUTHOR]

Substance transportation and clearance in the brain extracellular space (ECS) is crucial to brain function, but simulated microgravity disrupts substance diffusion and clearance in the brain ECS and there is limited knowledge regarding these disruptions. This study employed a tracer-based magnetic resonance imaging (MRI) technique to examine the impact of simulated microgravity on hippocampal ECS structure and the drainage of brain interstitial fluid (ISF) in a tail-suspended hindlimb-unloading rat model. The results demonstrated that under simulated microgravity conditions for 3, 7, and 14 days, the volume fraction of the hippocampal ECS increased in hindlimb unloading rats, and short-term (3 days) simulated microgravity expedited the drainage of the hippocampal ISF, but the drainage slowed under longer (7 or 14 days) simulated microgravity. These findings suggested that simulated microgravity alters the structure of the brain ECS and the speed of brain ISF drainage, which may have implications for space-flight-related brain injuries and relevant neuroprotective approaches via the brain ECS. • The tracer-based magnetic resonance imaging technique can measure structural and drainage of the brain extracellular space. • Volume fraction increases and tortuosity decreases in short-term simulated microgravity. • Impaired clearance of substances in simulated microgravity may be a mechanism leading to cognitive impairment in astronauts in space. [ABSTRACT FROM AUTHOR]

• A compact electro-adhesive hexapod robot is designed and prototyped. • A novel convertible limb that integrates manipulation and locomotion is proposed. • An optimized foot-trajectory subject to velocity and acceleration is developed. • Extensive simulations and ground experiments are performed. Service space robotics can provide on-orbit maintenance for faulty spacecrafts to extend life and reduce economic losses. In many cases, spacecraft failures are minor and can be easily recovered by completing simple manipulations or by providing observations. In this study, we propose a spacecraft surface adhesion-crawling-manipulation hexapod robot that can provide such services. To avoid increasing the payload, both of the robot's forelimbs were designed to be convertible, integrating manipulation and locomotion capabilities; the manipulation methods for the novel convertible limb are analyzed. A novel foot trajectory generation method is proposed to reduce the contact force generated when the foot of the robot touches the spacecraft surface and increase dynamic stability. Theoretical and experimental analyses of our robot are presented. Kinematic analyses are performed to validate the manipulation methods using convertible forelimbs. The stability of the robot's static adherence and dynamic crawling are analyzed in a microgravity simulation environment. A physical ground test is conducted to demonstrate the mobility and manipulation capabilities of the robot. [ABSTRACT FROM AUTHOR]

Cardiomyocytes derived from human induced pluripotent stem cells (hiPSC-CMs) possess tremendous potential for basic research and translational application. However, these cells structurally and functionally resemble fetal cardiomyocytes, which is a major limitation of these cells. Microgravity can significantly alter cell behavior and function. Here we investigated the effect of simulated microgravity on hiPSC-CM maturation. Following culture under simulated microgravity in a random positioning machine for 7 days, 3D hiPSC-CMs had increased mitochondrial content as detected by a mitochondrial protein and mitochondrial DNA to nuclear DNA ratio. The cells also had increased mitochondrial membrane potential. Consistently, simulated microgravity increased mitochondrial respiration in 3D hiPSC-CMs, as indicated by higher levels of maximal respiration and ATP content, suggesting improved metabolic maturation in simulated microgravity cultures compared with cultures under normal gravity. Cells from simulated microgravity cultures also had improved Ca2+ transient parameters, a functional characteristic of more mature cardiomyocytes. In addition, these cells had improved structural properties associated with more mature cardiomyocytes, including increased sarcomere length, z-disc length, nuclear diameter, and nuclear eccentricity. These findings indicate that microgravity enhances the maturation of hiPSC-CMs at the structural, metabolic, and functional levels. [ABSTRACT FROM AUTHOR]

Based on the real physical model and operating environment of the spacecraft tank, the numerical model of the tank is established and the sloshing behavior of liquid hydrogen in the tank under different longitudinal excitations is studied in this work. The Realizable k- ε model is used to predict the fluid turbulence, and the mixture model is used to analyze the phase transitions and flows. The harmonic external excitation is loaded by the user-defined function (UDF). Based on the CFD sloshing model verified through comparison with experimental results, the influences of different longitudinal external excitation frequencies and amplitudes on the liquid hydrogen volume fraction in the tank are firstly analyzed. On this basis, including pressure and other physical quantities of the monitoring points and whole internal fluid domain during the sloshing simulation process are studied quantitatively. In addition, the relationship between the carrier amplitude of the sloshing curves and the external excitation amplitude is discussed. The simulation results show that in microgravity environment, compared with large amplitude excitation, high-frequency longitudinal harmonic excitation has a significant effect on the variation of physical parameters in the tank, which may become a negative factor for the safety of liquid hydrogen storage and supply systems. Meanwhile, the traditional baffle design has a limited influence on the liquid hydrogen motion under the high-frequency longitudinal excitation which may occur during the spacecraft changing load process. The results provide valuable information for the understanding of sloshing behavior and safety evaluation of the tank under longitudinal excitation. • Longitudinal harmonic excitations are applied to a LH 2 tank in microgravity. • Excitation frequencies over 20 Hz significantly effect on the sloshing behavior. • The shape of the gas-liquid interface is insensitive to the excitation amplitude. • Baffles limit sloshing better at high amplitude excitations than at high frequency. [ABSTRACT FROM AUTHOR]

Recent spaceflights involving nonprofessional people have opened the doors to the suborbital space tourism business. However, they have also drawn public attention to the safety and hazards associated with space travel. Unfortunately, space travel involves a myriad of health risks for people, ranging from DNA damage caused by radiation exposure to the hemodynamic changes that occur when living in microgravity. In fact, the primary pathogenetic role is attributed to cosmic radiation, since deep space lacks the protective benefit of Earth's magnetic shielding. The second risk factor for space-induced pathologies is microgravity, which may affect organ function and cause a different distribution of fluid inside the human body. Both cosmic radiation and microgravity may lead to the alteration of cellular homeostasis and molecular changes in cell function. These, in turn, might have a direct impact on heart function and structure. The aim of this review is to draw attention to the fact that spaceflights constitute a novel frontier in biomedical research. We summarize the most important clinical and experimental evidence regarding the cardiovascular effects of cosmic radiation and microgravity. Finally, we highlight that unraveling the mechanisms underlying how space radiation and microgravity affect the cardiovascular system is crucial for identifying potential countermeasures and developing effective therapeutic strategies. [ABSTRACT FROM AUTHOR]

Cancer is defined as a group of diseases characterized by abnormal cell growth, expansion, and progression with metastasis. Various signaling pathways are involved in its development. Malignant tumors exhibit a high morbidity and mortality. Cancer research increased our knowledge about some of the underlying mechanisms, but to this day, our understanding of this disease is unclear. High throughput omics technology and bioinformatics were successful in detecting some of the unknown cancer mechanisms. However, novel groundbreaking research and ideas are necessary. A stay in orbit causes biochemical and molecular biological changes in human cancer cells which are first, and above all, due to microgravity (µg). The µg-environment provides conditions that are not reachable on Earth, which allow researchers to focus on signaling pathways controlling cell growth and metastasis. Cancer research in space already demonstrated how cancer cell-exposure to µg influenced several biological processes being involved in cancer. This novel approach has the potential to fight cancer and to develop future cancer strategies. Space research has been shown to impact biological processes in cancer cells like proliferation, apoptosis, cell survival, adhesion, migration, the cytoskeleton, the extracellular matrix, focal adhesion, and growth factors, among others. This concise review focuses on publications related to genetic, transcriptional, epigenetic, proteomic, and metabolomic studies on tumor cells exposed to real space conditions or to simulated µg using simulation devices. We discuss all omics studies investigating different tumor cell types from the brain and hematological system, sarcomas, as well as thyroid, prostate, breast, gynecologic, gastrointestinal, and lung cancers, in order to gain new and innovative ideas for understanding the basic biology of cancer. [ABSTRACT FROM AUTHOR]

As human spaceflight increases in duration, cultivation of crops in spaceflight is crucial to protecting human health under microgravity and elevated oxidative stress. Foodborne pathogens (e.g., Salmonella enterica) carried by leafy green vegetables are a significant cause of human disease. Our previous work showed that Salmonella enterica serovar Typhimurium suppresses defensive closure of foliar stomata in lettuce (Lactuca sativa L.) to ingress interior tissues of leaves. While there are no reported occurrences of foodborne disease in spaceflight to date, known foodborne pathogens persist aboard the International Space Station and space-grown lettuce has been colonized by a diverse microbiome including bacterial genera known to contain human pathogens. Interactions between leafy green vegetables and human bacterial pathogens under microgravity conditions present in spaceflight are unknown. Additionally, stomatal dynamics under microgravity conditions need further elucidation. Here, we employ a slow-rotating 2-D clinostat to simulate microgravity upon in-vitro lettuce plants following a foliar inoculation with S. enterica Typhimurium and use confocal microscopy to measure stomatal width in fixed leaf tissue. Our results reveal significant differences in average stomatal aperture width between an unrotated vertical control, plants rotated at 2 revolutions per minute (2 RPM), and 4 RPM, with and without the presence of S. typhimurium. Interestingly, we found stomatal aperture width in the presence of S. typhimurium to be increased under rotation as compared to unrotated inoculated plants. Using confocal Z-stacking, we observed greater average depth of stomatal ingression by S. typhimurium in lettuce under rotation at 4 RPM compared to unrotated and inoculated plants, along with greater in planta populations of S. typhimurium in lettuce rotated at 4 RPM using serial dilution plating of homogenized surface sterilized leaves. Given these findings, we tested the ability of the plant growth-promoting rhizobacteria (PGPR) Bacillus subtilis strain UD1022 to transiently restrict stomatal apertures of lettuce both alone and co-inoculated with S. typhimurium under rotated and unrotated conditions as a means of potentially reducing stomatal ingression by S. typhimurium under simulated microgravity. Surprisingly, rotation at 4 RPM strongly inhibited the ability of UD1022 alone to restrict stomatal apertures and attenuated its efficacy as a biocontrol following co-inoculation with S. typhimurium. Our results highlight potential spaceflight food safety issues unique to production of crops in microgravity conditions and suggest microgravity may dramatically reduce the ability of PGPRs to restrict stomatal apertures. [ABSTRACT FROM AUTHOR]

Examining the feat of maintaining life in orbit draws a sharp focus to the relationship between the human body and its environment, the porous and circulatory matter that blurs any boundaries between habitat and habitant. These intimate, engineered spaces evoke a microcosm of urgent planetary concerns surrounding air and water resources, and waste capture, storage, and elimination. This paper explores NASA's management of biological operations and discharge wastes in low gravity environments. Without strong gravitational fields, liquids coalesce at the location they are created, instead of flowing down and away. Such excesses disrupt the orderly engineered environments and minutely monitored bodies of these techno-scientific endeavors. Analyzing astronaut tears, space gynecology, zero-g surgery, and NASA's "Space Poop Challenge" through feminist queer and disability theory, new materialist, and discard studies lenses, this paper seeks to refigure the deeply entangled relationships between fleshy bodies and planetary bodies, biomass and geomass, and prompt new discussions of gravity politics. [ABSTRACT FROM AUTHOR]

Thrombotic disease may be an underdiagnosed condition of prolonged exposure to microgravity and yet the underlying factors remain poorly defined. Recently, an internal jugular vein thrombosis was diagnosed in a low-risk female astronaut after an approximately 7-week space mission. Six of the additional 10 crew members demonstrated jugular venous flow risk factors, such as suspicious stagnation or retroversion. Fortunately, all were asymptomatic. Observations in space as well as clinical and in vitro microgravity studies on Earth, where experiments are designed to recapitulate the conditions of space, suggest effects on blood flow stasis, coagulation, and vascular function. In this article, the related literature on thrombotic disease in space is reviewed, with consideration of these elements of Virchow's triad. • Asymptomatic internal jugular vein thrombosis (IJV) was detected in an astronaut. • Exposure to microgravity may cause unforeseen risk during long-term spaceflight. • Studies on thrombosis risk in space and analogous models on Earth are limited. • Microgravity affects the blood flow stasis, coagulation, and endothelial triad. • Here, the pathophysiological and biomolecular evidence are examined. [ABSTRACT FROM AUTHOR]

There is a broad interest in both industry and academe in understanding the time-evolution in the microstructure of colloidal gels, as such changes affect the properties of the gels including product self-life and rheology. In colloidal gels, the time-evolution results from the magnitude and the relative proportions of forces—including gravity, acting on the colloidal particles. The aim of this study was to measure the magnitude of the Soret force acting on the colloidal particles in a model gel in the microgravity on the International Space Station, as a proxy for gravitational forces in Earth-based experiments. It was found that the Soret force could be used to create an effective gravitational force of between about 10 × 10−17 N (3 milli-G) and 3 × 10−17 N (1 milli-G) on the colloidal particles, where the lower limit is set by the dominance of particle flux from Brownian forces. These results should allow mapping the behavior of colloidal gels broadly described in literature on other gels—such as polymer gels of industrial interest, where the colloidal particles are much smaller. [ABSTRACT FROM AUTHOR]

The flame spread behavior over a filter paper in opposed flow was investigated on the ISS/Kibo, and the results were compared with the flammability map predicted in advance by scale analysis for a two-dimensional flame. The on-orbit experiments were conducted in the solid combustion experimental module (SCEM) as the first combustion test of the FLARE project by JAXA. A filter paper with a length of 130 mm, a width of 40 mm or 20 mm, and a thickness of 0.12 mm was used as the specimen. The opposed flow velocity and the oxygen concentration were varied from 0 cm/s to 25 cm/s, and from 13.5% to 34%, respectively. The ambient pressure is 101.3 kPa. The predicted limiting curve reasonably agreed with the minimum limiting oxygen concentration observed. On the other hand, in extremely slow flows, very robust flames were observed beyond the limiting curve. When the condition reached the limit of two-dimensional flame, the flame front changed from a linear shape to a spherical shape (flamelet) to shorten the preheat zone length, reducing the radiative heat loss to survive. In these cases, the flamelet was sustained for a long time (> 100 s), and a large amount of decomposed gas was released at the periphery of the pyrolysis zone generating a combustible vapor cloud around the spherical flame font. The presence of a long-life robust flamelet and the accumulation of such combustible mist can be fire hazards in microgravity. [ABSTRACT FROM AUTHOR]

Space-related stressors such as microgravity are associated with cellular and molecular alterations of the immune and inflammatory homeostasis that have been linked to the disorders that astronauts suffer from during their missions. Most of the research of the past 30 years has consistently established that innate adaptive immune cells represent a target of microgravity, which leads to their defective or dysfunctional activation, as well as to an altered ability to produce soluble mediators—e.g., cytokines/chemokines and bioactive lipids—that altogether control tissue homeostasis. Bioactive lipids include a vast array of endogenous molecules of immune origin that control the induction, intensity and outcome of the inflammatory events. However, none of the papers published so far focus on a newly characterized class of lipid mediators called specialized pro-resolving mediators (SPMs), which orchestrate the "resolution of inflammation"—i.e., the active control and confinement of the inflammatory torrent mostly driven by eicosanoids. SPMs are emerging as crucial players in those processes that avoid acute inflammation to degenerate into a chronic event. Given that SPMs, along with their metabolism and signaling, are being increasingly linked to many inflammatory disorders, their study seems of the outmost importance in the research of pathological processes involved in space-related diseases, also with the perspective of developing therapeutic countermeasures. Here, we show that microgravity, simulated in the rotary cell culture system (RCCS) developed by NASA, rearranges SPM receptors both at the gene and protein level, in human monocytes but not in lymphocytes. Moreover, RCCS treatment reduces the biosynthesis of a prominent SPM like resolvin (Rv) D1. These findings strongly suggest that not only microgravity can impair the functioning of immune cells at the level of bioactive lipids directly involved in proper inflammation, but it does so in a cell-specific manner, possibly perturbing immune homeostasis with monocytes being primary targets. [ABSTRACT FROM AUTHOR]

The microgravity conditions in outer space are widely acknowledged to induce significant bone loss. Recent studies have implicated the close relationship between Atp6v1h gene and bone loss. Despite this, the role of Atp6v1h in bone remodeling and its molecular mechanisms in microgravity have not been fully elucidated. To address this, we used a mouse tail suspension model to simulate microgravity. We categorized both wild-type and Atp6v1h knockout (Atp6v1h+/-) mice into two groups: regular feeding and tail-suspension feeding, ensuring uniform feeding conditions across all cohorts. Analysis via micro-CT scanning, hematoxylin-eosin staining, and tartrate-resistant acid phosphatase assays indicated that wild-type mice underwent bone loss under simulated microgravity. Atp6v1h+/- mice exhibited bone loss due to Atp6v1h deficiency but did not present aggravated bone loss under the same simulated microgravity. Transcriptomic sequencing revealed the upregulation of genes, such as Fos, Src, Jun, and various integrin subunits in the context of simulated microgravity and Atp6v1h knockout. Real-time quantitative polymerase chain reaction (RT-qPCR) further validated the modulation of downstream osteoclast-related genes in response to interactions with ATP6V1H overexpression cell lines. Co-immunoprecipitation indicated potential interactions between ATP6V1H and integrin beta 1, beta 3, beta 5, alpha 2b, and alpha 5. Our results indicate that Atp6v1h level influences bone loss in simulated microgravity by modulating the Fos-Jun-Src-Integrin pathway, which, in turn, affects osteoclast activity and bone resorption, with implications for osteoporosis. Therefore, modulating Atp6v1h expression could mitigate bone loss in microgravity conditions. This study elucidates the molecular mechanism of Atp6v1h's role in osteoporosis and positions it as a potential therapeutic target against environmental bone loss. These findings open new possibilities for the treatment of multifactorial osteoporosis. [ABSTRACT FROM AUTHOR]

Auricularia auricula polysaccharides used in Pinus koraiensis polyphenol encapsulation and delivery under weightlessness are rarely reported. In this study, an anionic polysaccharide fragment named AAP Iα with a molecular weight of 133.304 kDa was isolated and purified to construct a polyphenol encapsulation system. Nanoparticles named NPs-PP loaded with a rough surface for Pinus koraiensis polyphenol (PP) delivery were fabricated by AAP Iα and ε-poly-L-lysine (ε-PL). SEM and the DLS tracking method were used to observe continuous changes in AAP Iα, ε-PL and PP on the nanoparticles' rough surface assembly, as well as the dispersion and stability. Hydrophilic, monodisperse and highly negative charged nanoparticles can be formed at AAP Iα 0.8 mg/mL, ε-PL 20 μg/mL and PP 80 μg/mL. FT-IR was used to determine their electrostatic interactions. Release kinetic studies showed that nanoparticles had an ideal gastrointestinal delivery effect. NPs-PP loaded were assembled through electrostatic interactions between polyelectrolytes after hydrogen bonding formation in PP-AAP Iα and PP-ε-PL, respectively. Colon adhesion properties and PP delivery in vivo of nanoparticles showed that NPs-PP loaded had high adhesion efficiency to the colonic mucosa under simulated microgravity and could enhance PP bioavailability. These results suggest that AAP Iα can be used in PP encapsulation and delivery under microgravity in astronaut food additives. [ABSTRACT FROM AUTHOR]

Development of efficient and safe energy systems for space objects includes ensuring fire safety. This problem requires a deep understanding of influence of gravitational forces on combustion processes, which explains the importance of studying this issue. The paper analyzes the dynamics of inverted conical methane-air flame under conditions of normal and reverse gravitational force with external acoustic excitation. Applied frequencies of acoustic excitation could be parasitic or be produced during proper work of different technical systems of aircraft. High speed recording of flame chemiluminescence and PIV analysis were conducted. Decomposition of flow vector pictures into the modes was calculated using POD method. Energy contribution into the flow was analyzed for its separate elements at the different frequencies of excitation. At the high excitation frequencies vortex generation intensity in the shear layer with reverse gravity is about the same as it was observed in the experiments with normal gravity direction, that could indicate dominance of acoustic mechanism of the vortexes stimulation over the mechanism of shear instability. At external excitation frequency equals 240 Hz significant growth of shear vortex diameters and increasing of perpendicular oscillations amplitude of flame branches were obtained. Thereby in such experiment with 240 Hz external acoustic excitation the most intensive large scale instability of flow was observed. • The smallest vortices sizes are observed at 0 and 60 Hz excitation frequencies. • At excitation of 160, 240 and 420 Hz the vortices are non-affected by the gravity. • Vortice sizes and transverse oscillation range approach maximum at 240 Hz excitation. [ABSTRACT FROM AUTHOR]

Understanding the mechanisms and dynamics of molten metal droplet transfer within the plasma of a directed energy deposition arc process in microgravity is critical for optimizing the build process with minimal defects. This paper presents a unique experimental setup designed to investigate the transfer of molten metal droplets in the microgravity environment of a drop tower. The primary design of the apparatus revolves around accommodating, within the confines of the drop tower experimental capsule, essential components, including a high-speed camera with necessary filters for capturing molten metal droplets, a consumable electrode wire-arc setup, batteries, a linear traverse stage for single bead deposition, sensors, data acquisition systems, online communication systems, and the control system. These systems are secured to withstand the high deceleration forces at the end of a free fall in the drop tower. The arrangement has demonstrated consistent deposition outcomes, capturing clear images of droplet transfers using a high-speed camera along with voltage, current, and temperature data during the microgravity state induced by free fall. This apparatus will serve as a foundational element in establishing a viable additive manufacturing capability for space applications, as it provides fundamental insights into the transfer of molten metal droplets. [ABSTRACT FROM AUTHOR]

Objective: 1. Secure resources for systems reliability and safety while exploring the development of a necessary human survival system and infrastructure for a 2.5 year-round trip journey to explore Mars by 2050. 2. Inform the reader and potential mission explorers of the challenges that will be faced in the transit and establishment phases of the Mars endeavor. [ABSTRACT FROM AUTHOR]

During future space missions, astronauts will be exposed to cosmic radiation and microgravity (μG), which are known to be health risk factors. To examine the differentially expressed genes (DEG) and their prevalent biological processes and pathways as a response to these two risk factors simultaneously, 1BR-hTERT human fibroblast cells were cultured under 1 gravity (1G) or simulated μG for 48 h in total and collected at 0 (sham irradiated), 3 or 24 h after 1 Gy of X-ray or Carbon-ion (C-ion) irradiation. A three-dimensional clinostat was used for the simulation of μG and the simultaneous radiation exposure of the samples. The RNA-seq method was used to produce lists of differentially expressed genes between different environmental conditions. Over-representation analyses were performed and the enriched biological pathways and targeting transcription factors were identified. Comparing sham-irradiated cells under simulated μG and 1G conditions, terms related to response to oxygen levels and muscle contraction were identified. After irradiation with X-rays or C-ions under 1G, identified DEGs were found to be involved in DNA damage repair, signal transduction by p53 class mediator, cell cycle arrest and apoptosis pathways. The same enriched pathways emerged when cells were irradiated under simulated μG condition. Nevertheless, the combined effect attenuated the transcriptional response to irradiation which may pose a subtle risk in space flights. [ABSTRACT FROM AUTHOR]

Future in situ resource utilisation (ISRU) lunar mission concepts will require mechanisms that allow the available feedstock–mainly the lunar regolith–to be extracted from the lunar surface. Such extraction techniques in the reduced gravity environment of the Moon will need to minimise excavation forces, due to mass restrictions for robotic landers/vehicles and the large financial implications of placing cargo onto Earth's satellite. An investigation of necessary excavation forces, both horizontally as well as vertically, for small-scale continuous lunar excavation systems based on their geometric inlet shapes, cutting angles, and digging depths has been undertaken. The use of vibration to disaggregate lunar soil and to reduce the necessary forces is explored as a proof-of-concept. Tests performed in a large analogue testbed have shown that the optimisation of the cutting geometry is crucial, as it inherently influences the necessary forces or even prevents deeper cuts into the soil. Our experiments indicate that shallow cuts (low digging depth) into soil at shallow angles are beneficial, and that the piling up of large surcharge masses must be avoided. Critically, applying vibration to cutting edges seems highly beneficial, as the achievable force reductions of up to 50% in the tested conditions far outweigh the additional power requirements. To make these implications immediately applicable to a wider audience, an estimation of available traction forces for certain robotic vehicles based on their mass is added for comparison. [ABSTRACT FROM AUTHOR]