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A lattice Boltzmann model for two-phase fluids is used to find the equilibrium distribution of density and pressure across a vertical column under the action of terrestrial gravitational field. At low temperatures and without surface tension, the density distribution has a discontinuity point due to phase separation, while the pressure is always continuous. At temperatures far above the critical point, the fluid column behaves as an ideal gas and the well-known barometric formula is recovered. When surface tension is considered, this model gives also the correct behavior of a Van der Waals fluid placed in a tank subjected to terrestrial or space conditions in both cases, when the tank walls are wetted or not by the fluid.

We investigated the effects of three traditional Chinese medicine prescriptions on changes of bone metabolism in mice, using a gravity device to produce a microgravity environment. We found that Hochu-ekki-to (TJ-41) and Hachimi-jio-gan (TJ-7) suppress the increase in the ratio of serum Ca/P and the increase of calcium in urine. Moreover, TJ-41 and Shin-bu-to (TJ-30) reversed the increase of alkaline phosphatase activity (ALP), and TJ-41 also reversed the decrease of estradiol in the serum. The mechanism may be that the traditional Chinese medicines increased estradiol, causing the decrease of ALP, which induced the changes of Ca and P in serum, leading to a decreased excretion of Ca in urine. In this study, TJ-41 was effective in every parameter while TJ-7 and TJ-30 was effective on some parameters, showing that traditional Chinese medicines have specificities in the space environment. In conclusion, this study suggests that some traditional Chinese medicines may be beneficial for adaptation to a space environment.

The relevance of self-organization, nonlinear phenomena and nonequilibrium behavior in a wide range of problems in space science and microgravity research, calls for a concerted approach using the tools of statistical physics, thermodynamics, nonlinear dynamics, mathematical modeling and numerical simulation, in synergy with experimentally oriented work.

The reason behind the ubiquity of such concepts is that in many instances of relevance in space science one witnesses an interplay between molecular and macroscopic-level entities and processes, such as nucleation in phase transitions or aggregation and self-assembly in materials science and biology. These phenomena are fundamentally dynamic in nature. We present two minimal models one dealing with issues of complex behavior at the microscopic level and the second referring to the strong nonlinear nature of macroscopic evolution, relevant to soft-condensed matter under observation both on the ground and in microgravity conditions.

These investigations open the way to a whole class of unexpected situations whose proper characterization and control can only be expected in the framework of nonequilibrium physics and complexity theory.

Weightlessness promises to substantially extend the science of quantum gases toward presently inaccessible regimes of low temperatures, macroscopic dimensions of coherent matter waves, and enhanced duration of unperturbed evolution. With the long-term goal of studying cold quantum gases on a space platform, we currently focus on the implementation of an ⁸⁷Rb Bose–Einstein condensate (BEC) experiment under microgravity conditions at the ZARM drop tower in Bremen (Germany). Special challenges in the construction of the experimental setup are posed by a low volume of the drop capsule (< 1 m³) as well as critical vibrations during capsule release and peak decelerations of up to 50 g during recapture at the bottom of the tower. All mechanical and electronic components have thus been designed with stringent demands on miniaturization, mechanical stability and reliability. Additionally, the system provides extensive remote control capabilities as it is not manually accessible in the tower two hours before and during the drop. We present the robust system and show results from first tests at the drop tower.

Weightlessness environment (also microgravity) during the exploration of space is the major condition which must be faced by astronauts. One of the most serious adverse effects on astronauts is the weightlessness-induced bone loss due to the unbalanced bone remodeling. Bone remodeling of human beings has evolved during billions of years to make bone tissue adapt to the gravitational field of Earth (1g) and maintain skeleton structure to meet mechanical loading on Earth. However, under weightlessness environment the skeleton system no longer functions against the pull of gravity, so there is no necessity to keep bone strong enough to support the body's weight. Therefore, the balance of bone remodeling is disrupted and bone loss occurs, which is extremely deleterious to an astronaut's health during long-term spaceflight. Bone remodeling is mainly orchestrated by bone mesenchymal stem cells, osteoblasts, osteocytes, and osteoclasts. Here, we review how these bone cells respond to microgravity environment.

Background: Compact bone mainly consists of cylindrical osteon structures. In microgravity, the change in the mechanical microenvironment of osteocytes might be the root cause of astronauts’ bone loss during space flights.

Methods: A multi-scale three-dimensional (3D) fluid–solid coupling finite element model of osteons with a two-stage pore structure was developed using COMSOL software based on the natural structure of osteocytes. Gradients in gravitational fields of $-$1, 0, 1, 2.5, and 3.7g were used to investigate the changes in the mechanical microenvironment on osteocyte structure. The difference in arteriole pulsating pressure and static compression stress caused by each gravity gradient was investigated.

Results: The mechanical response of osteocytes increased with the value of g, compared with the Earth’s gravitational field. For instance, the fluid pressure of osteocytes and the von Mises stress of bone matrix near lacunae decreased by 31.3% and 99.9%, respectively, in microgravity. Under static loading, only about 16.7% of osteocytes in microgravity and 58.3% of osteocytes in the Earth’s gravitational field could reach the fluid shear stress threshold of biological reactions in cell culture experiments. Compared with the Earth’s gravitational field, the pressure gradient inside osteocytes severely decreased in microgravity.

Conclusion: The mechanical microenvironment of osteocytes in microgravity might cause significant changes in the mechanical microenvironment of osteocytes, which may lead to disuse osteoporosis in astronauts.

Orbit refueling is one of the most significant technologies, which has vital strategic meaning. It can enhance the flexibility and prolong the lifetime of the spacecrafts. Space propellant management is one of the key technologies in orbit refueling. Based on the background of space propellant management, CFD simulations of capillary rise of liquid in Cylindrical container with lateral vanes in space condition were carried out in this paper. The influence of the size and the number of the vanes to the capillary flow were analyzed too. The results can be useful to the design and optimization of the propellant management device in the vane type surface tension tank.

Single protein crystals are indispensable in the determination of the three-dimensional structure of proteins and other biological macromolecules by X-ray crystallography. The quality of the crystals governs the resolution limit or accuracy of the atomic positions calculated. The purpose of this chapter is to describe the idea of using magnetic fields to grow better quality protein crystals. The possibilities as well as limitations will be discussed.

Weightlessness promises to substantially extend the science of quantum gases toward presently inaccessible regimes of low temperatures, macroscopic dimensions of coherent matter waves, and enhanced duration of unperturbed evolution. With the long-term goal of studying cold quantum gases on a space platform, we currently focus on the implementation of an ⁸⁷Rb Bose–Einstein condensate (BEC) experiment under microgravity conditions at the ZARM drop tower in Bremen (Germany). Special challenges in the construction of the experimental setup are posed by a low volume of the drop capsule (< 1 m³) as well as critical vibrations during capsule release and peak decelerations of up to 50 g during recapture at the bottom of the tower. All mechanical and electronic components have thus been designed with stringent demands on miniaturization, mechanical stability and reliability. Additionally, the system provides extensive remote control capabilities as it is not manually accessible in the tower two hours before and during the drop. We present the robust system and show results from first tests at the drop tower.

A microgravity 14-year-long data set (October 1994-September 2007) recorded along a 24-kilometer East-West trending profile of 19 stations was analyzed to detect underground mass redistributions related to the volcanic activity involving the southern flank of Mt. Etna volcano (Italy). An important issue with the above data-set is the need of separating the useful signal (i.e. the volcanorelated one) from unwanted components (instrumental, human-made, seasonal and other kinds of noise). To filter the gravity data-set from these last components we propose the wavelet multi-resolution analysis. This method provides a good separation of the long period component from the short period one, and allows exploring the local features of the signal with a detail matched to their characteristic scale. Once the useful signal has been suitably separated from the noise, the residual space-time-image evidences gravity anomalies correlated with the ensuing volcanic activity.