Microgravity Science and Technology最新文献

This study investigated the impact of simulated microgravity on titanium implant osseointegration and assessed the reparative efficacy of icariin (ICA) combined with treadmill exercise. Male Sprague–Dawley rats (n = 24) were divided into four groups: normal gravity control (CON), simulated microgravity (SMG), SMG + ICA, and SMG + ICA+treadmill exercise (SMG + ICA+EXER). SMG groups underwent tail suspension for four weeks, followed by ICA (25 mg/kg/day) and/or exercise interventions. Micro-CT, fluorochrome labeling, toluidine blue staining, and biomechanical tests were performed at week 8. Micro-CT analysis revealed that Groups SMG, SMG + ICA, and SMG + ICA+EXER exhibited a gradual increase in Tb.Th, Tb.BV/TV, DA, Tb.BMD, and Tb.BMC, and a gradual decrease in BS/BV, Tb.Sp, and SMI compared to Group CON, Mineral apposition rate (MAR) and bone-to-implant contact (BIC) were also significantly higher in ICA groups ( P < 0.05 ), matching CON levels ( P > 0.05 ). Biomechanical strength was enhanced in ICA groups, with superior performance in SMG + ICA+EXER. Simulated microgravity impairs osseointegration, but ICA mitigates these effects, with treadmill exercise further augmenting bone integration and biomechanical strength. This combined strategy may serve as a viable countermeasure for maintaining implant stability in space medicine.

Owing to the difference in convective heat transfer mechanisms between space and ground, the temperature profile of lightweight high-entropy alloys (HEAs) in space is different from the ground which may prevent the samples from melting as intended and thus cause the space experiment to fail. To predict the temperature profile and obtain the heat transfer characteristics in space, it employed experimental temperature data of the standard SCA at 800 °C under both ground and space. Specifically, numerical models of the high-temperature furnace and SCA were established, and different operating conditions and relevant thermophysical parameters were adjusted to conduct the thermal simulations of the temperature profile of the SCA in space and on ground. The respective heat transfer characteristics for space and ground were thus obtained. Based on the obtained heat transfer characteristics, the temperature profile and heat transfer characteristics of the lightweight HEA experiment in space were predicted when the furnace temperature is 900 °C, the target experimental temperature from the ground-based HEA experiment. The results provide an important foundation for conducting HEA solidification experiments in microgravity.

For disclose the 3D spatiotemporal oscillation characteristics of nanofluid thermocapillary convection, this paper numerically studies the supercritical oscillatory process of nanofluids thermocapillary convection in a 3D rectangular cavity under microgravity conditions, and the propagation characteristics of flow field and temperature waves are analyzed. The results show that, under supercritical condition the flow field is composed of multiple dynamically migrating convective vortices, and the periodic temperature waves not only appear at free surface, but also inside the liquid layer. With increasing nanoparticle volume fraction, both the dominant frequency and amplitude of velocity oscillation exhibit linear reduction, while the oscillation period increases linearly. Furthermore, the propagation angle of hydrothermal waves increases progressively with nanoparticles volume fraction increasing, particularly, the angle from 27.5° increases to 33° as nanoparticles volume fraction varies from 0 to 0.05.

Brazing of aluminum alloys using chemically active fillers is in demand in transportation and aerospace engineering for the development of new techniques suitable under microgravity conditions for outer space repair. This work presents a theoretical study of diffusion and hydrodynamic flows in molten Zn solder during the reactive wetting of an Al–Mg-Mn plate under various gravity conditions. The model is developed in the isothermal formulation at different wetting temperatures, considering the concentration-driven effect in the soldered zone. The influence of Marangoni convection caused by the Zn concentration gradient on the flow structure and erosion of the base material is analyzed. The effect of zinc evaporation during reactive wetting under vacuum conditions is revealed and quantitatively described. The dependency of the Zn solder droplet radius during its spreading on a flat Al–Mg-Mn plate under various external conditions is also analyzed.

Prolonged immersion in thermoneutral water reproduces several physiological adaptations of orbital flight but its endocrine‑immune consequences remain incompletely characterised. We investigated stress hormones and immune markers in two healthy divers undergoing a 25‑h shallow‑water immersion and compared the findings with contemporary microgravity literature. Peripheral blood was collected one day before and < 15 min after immersion. Flow cytometry, 51Cr‑release assay, lymphocyte proliferation, intracellular cytokine PCR and routine endocrinology panels were performed. All data were corrected for plasma‑volume shifts. Cortisol, growth hormone and prolactin increased by 45–100%, whereas testosterone declined modestly. CD56⁺ natural killer (NK)‑cell frequency fell (‑25% and ‑32%) without loss of cytotoxicity. PBMC proliferation in response to phytohaemagglutinin decreased (‑30% to ‑45%). A Th1 → Th2 cytokine shift was evident with lower IFN‑γ and higher IL‑4 expression. These responses mirror patterns reported after head‑down bed rest and long‑duration spaceflight. Extended shallow‑water immersion is sufficient to activate the neuro‑endocrine stress axis and induce selective, microgravity‑like immune alterations. Thermoneutral immersion may therefore serve as a cost‑effective analogue for mechanistic studies and countermeasure testing.

This study focused on microhemodynamic and autonomic regulation changes during long-term isolation in a 366-day SIRIUS-23 experiment with 6 healthy volunteers (2 men and 4 women, aged 25–37 years). Heart rate variability analysis and laser Doppler flowmetry were used to assess cardiovascular system responses before, during, and after isolation. Volunteers demonstrated distinct autonomic regulation patterns, dividing into two groups based on vagal tone and vascular center activity. Group 2 showed consistently higher autonomic function throughout the experiment. Microcirculation parameters revealed decreased perfusion in the forehead area for Group 1 and fluctuating dynamics for Group 2. Both groups exhibited endothelial tone reduction and altered blood flow distribution in the toe area with increased shunt flow. Prolonged isolation significantly affects microhemodynamics and autonomic regulation. Individuals with higher vagal tone demonstrated better adaptation. These findings contribute to understanding physiological responses to long-term confinement and have implications for space mission medical support.

Fluid flow and phase-change processes under variable-gravity are of significant scientific interest in space science, thermal control engineering and planetary exploration. However, current variable and micro-gravity experiments mainly rely on space stations or parabolic flights, which are limited by short experimental durations, high costs, and restricted repeatability. To overcome these limitations, this study develops a ground-based experimental approach on diamagnetic levitation. Deionized water is adopted as the working fluid in a strong magnetic field to conduct representative variable-gravity experiments, including single-droplet levitation, liquid bridge formation, capillary flow, and boiling. The experimental results show that: in the single-droplet levitation experiment, stable levitation can be achieved when the central magnetic field reached 23.28 T. In the capillary rise experiment under typical gravity conditions, the maximum deviation between the measured liquid height and the theoretical prediction is 5.25%. In the liquid bridge experiment, the difference between the measured maximum diameter and the theoretical prediction is only 0.07 mm. In the boiling experiment, distinct boiling behaviors are successfully observed under different effective gravity levels. It can also be used to construct simulated gravity experimental conditions on the surfaces of planets such as the Moon and Mars. These results demonstrate that the proposed experimental approach enables stable, long-duration, high-precision, and cost-effective simulation of micro/reduced-gravity environments. This work establishes a ground-based diamagnetic gravity-compensation facility that enables controlled studies of fluid flow and phase-change heat transfer in diamagnetic fluids under magnetically compensated effective gravity conditions, offering valuable insights for space and planetary thermal-fluid applications.

Long-duration spaceflight has revealed a distinctive constellation of neuro-ocular abnormalities, collectively known as Spaceflight-Associated Neuro-Ocular Syndrome (SANS). These are hypothesized to result from cephalad fluid shifts in microgravity, leading to altered cerebrovascular dynamics and suspected mild elevations in intracranial pressure (ICP). Invasive ICP monitoring techniques are unsuitable for spaceflight, prompting the development and validation of non-invasive alternatives, including optic nerve sheath diameter (ONSD) ultrasound and transcranial Doppler (TCD), which offer practical and reliable surrogates for estimating ICP. When combined, these methods can improve diagnostic accuracy and enable multimodal neuromonitoring. Integration of rapidly advancing artificial intelligence (AI) models into ONSD and TCD systems can further enhance precision, reduce operator dependence, and enable automated trend analysis. This paper examines current advances in non-invasive ICP monitoring within space medicine, evaluates their readiness for operational deployment, and identifies key challenges related to standardization, calibration, and validation. These breakthroughs hold substantial promise for supporting astronaut health during spaceflight and planetary missions, while also advancing neurocritical care on Earth.

Spaceflight missions have advanced techniques over the last decades, with astronauts spending their time for more than 6 months aboard the International Space Station. Nevertheless, the living and working conditions in outer space remain highly challenging and demanding for astronauts. Space science has also been a frontier area in life science research, which targets studying the human physiology of living beings and their physiological changes under microgravity. This review highlights the impact of microgravity on the alteration of human, plant, microbial, and rodent physiology, emphasising the effects of microgravity on the physiology of these organisms in a space environment. Different countries have their own space agencies, and they have increased their space research over the past few decades in preparation for future space missions. The spaceflight radiation-induced carcinogenic effects have emerged as a health risk during deep spaceflight missions. In the recent era, a huge number of cell-line and animal model experimental studies have been conducted to explore the microgravity radiation, lower and higher doses of radiation, heavy ions, and low Earth orbital environments have identified evident carcinogenicity. Deep space flight mission leads to Spaceflight Associated Neuro-ocular Syndrome and associated other diseases such as glaucoma, alzheimer’s disease, cerebral edema, and cancer. In this review, we have summarized the objectives of space biology, the historical background of different space agencies, different types of space radiation associated with several diseases, multiscale biological experiments under microgravity, and biological specimen experiments under different space agencies.

The paper is devoted to the study of the process of cleaning a microchannel contaminated by impurity particles settling on its walls. The most common reason of microchannel clogging is the sorption of impurity particles by pore walls or “physical sorption”. This paper describes the problem of drift of solid non-interacting particles in a microchannel, which can stick to its walls under the action of the van der Waals forces and break away from the wall due to thermal noise and viscous stresses arising from the flow. The pressure drop is given between the channel inlet and outlet. At the initial moment of time, the channel walls are contaminated with adhered particles, i.e. the walls are uneven, which affects the formation of the flow structure through the channel. Over time, under the action of viscous stresses and thermal noise, the particles break away from the channel walls, causing its cleaning. The interaction of the detached particles with the flow is taken into account in the approximation of the laminar flow regime. In addition, the model takes into account random particle motion caused by diffusion. The problem is solved numerically within the framework of the random walk model. The evolution of the liquid flow in the channel during its cleaning is obtained: stream function, pressure, and vorticity fields. It is demonstrated that three cleaning scenarios can be observed: no cleaning, slow cleaning, and fast cleaning. To control the cleaning scenario the modulation of the pressure drop at the channel borders is investigated. It is shown that resonance phenomena can be observed. The dependencies of cleaning time on the modulation amplitude and frequency is obtained and studied. It is shown that changing the modulation parameters leads to a significant change in the cleaning time and helps control the cleaning process.