Microgravity Environment Of Space Research Articles

The interaction between Aspergillus brasiliensis and exposed copper circuits in the space microgravity environment

In the space station, filamentous fungi are one of the main potential hazards causing short circuits or corrosion failure of printed circuit boards (PCBs). A 90-day fungal corrosion test was carried out on the China Space Station (CSS), focusing on the interaction between A. brasiliensis and exposed copper circuits. The results showed that the mycelial morphology, ultrastructure, and organic acid accumulation of the test fungi exhibited significant changes in the space microgravity environment. Aspergillus brasiliensis tended to excrete higher levels of oxalic acid in space as a defense mechanism against copper toxicity, which could exacerbate localized corrosion of copper metal.

Study on biodegradation of polyurethane coating on PCB by Aspergillus brasiliensis in space

Polyurethane (PU) is a commonly used conformal coating for printed circuit boards (PCBs). Filamentous fungi present in the space station environment are capable of degrading PU coatings, thereby posing a threat to the safety of electronic components. Therefore, we conducted a 90-day interaction test between Aspergillus brasiliensis and PU-coated PCBs in the China Space Station (CSS) and a controlled environment on the ground. This research aimed to investigate the alterations in the physiological properties of A. brasiliensis on PCB surfaces and the deterioration behavior of PU coating systems in the space microgravity environment. The results show that many fungal parameters, such as growth, morphology, cell ultrastructure, and low molecular weight organic acids (LMWOA) accumulation showed strong changes after spaceflight compared to ground controls. Distinct corrosion morphological features were found in the internal coatings by FIB/SEM analysis, suggesting the existence of a particular deterioration mechanism in the microgravity environment, which requires further investigation.

Comparative Studies on Effects of Simulated Microgravity on Growth and Photosynthetic Parameters in Rice and Mungbean

Microgravity or low gravity environment of space can be simulated on Earth by using clinorotation with appropriate speed of rotation. Previous reports show that microgravity environment (real or simulated) affects growth, chlorophyll content and photosynthetic performance in different plants. However, most of the reports showed variation in results. Earlier studies carried out on simulated microgravity (SMG) using clinorotation in our laboratory showed increase in growth, chlorophyll content and various yield attributes in case of laboratory and field grown rice. Subsequent studies were carried out on mungbean seedlings. In the present work, comparative aspects of these studies are reported. Results of the present study showed increase in growth, chlorophyll content and chlorophyll fluorescence parameters in SMG samples as compared to control samples in rice and mungbean seedlings. Interestingly, percentage of enhancement in growth, chlorophyll content and chlorophyll fluorescence parameters of SMG samples is significantly higher in rice (monocotyledonous) seedlings as compared to mungbean (dicotyledonous).

Neurostimulation as a technology countermeasure for dry eye syndrome in astronauts

Dry eye syndrome (DES) poses a significant challenge for astronauts during space missions, with reports indicating up to 30% of International Space Station (ISS) crew members. The microgravity environment of space alters fluid dynamics, affecting distribution of fluids on the surface of the eye as well as inducing cephalad fluid shifts that can alter tear drainage. Chronic and persistent DES not only impairs visual function, but also compromises the removal of debris, a heightened risk for corneal abrasions in the microgravity environment. Despite the availability of artificial tears on the ISS, the efficacy is challenged by altered fluid dynamics within the bottle and risks of contamination, thereby exacerbating the potential for corneal abrasions. In light of these challenges, there is a pressing need for innovative approaches to address DES in astronauts. Neurostimulation has emerged as a promising technology countermeasure for DES in spaceflight. By leveraging electrical signals to modulate neural function, neurostimulation offers a novel therapeutic avenue for managing DES symptoms. In this paper, we will explore the risk factors and current treatment modalities for DES, highlighting the limitations of existing approaches. Furthermore, we will delve into the novelty and potential of neurostimulation as a countermeasure for DES in future long-duration missions, including those to the Moon and Mars.

Enhancing cell-scale performance via sustained release of the varicella-zoster virus antigen from a microneedle patch under simulated microgravity.

The immune system of astronauts might become weakened in the microgravity environment in space, and the dormant varicella-zoster virus (VZV) in the body might be reactivated, seriously affecting their work and safety. For working in orbit for the long term, there is currently no efficient and durable delivery system of general vaccines in a microgravity environment. Accordingly, based on the previous foundation, we designed, modified, and synthesized a biodegradable and biocompatible copolymer, polyethylene glycol-polysulfamethazine carbonate urethane (PEG-PSCU) that could be mainly adopted to fabricate a novel sustained-release microneedle (S-R MN) patch. Compared with conventional biodegradable microneedles, this S-R MN patch could not only efficiently encapsulate protein vaccines (varicella-zoster virus glycoprotein E, VZV gE) but also further prolong the release time of VZV gE in a simulated microgravity (SMG) environment. Eventually, we verified the activation of dendritic cells by VZV gE released from the S-R MN patch in an SMG environment and the positive bioeffect of activated dendritic cells on lymphocytes using an in vitro lymph node model. This study is of great significance for the exploration of long-term specific immune responses to the VZV in an SMG environment.

The Impact of Microgravity on Immunological States.

As we explore other planetary bodies, astronauts will face unique environmental and physiological challenges. The human immune system has evolved under Earth's gravitational force. Consequently, in the microgravity environment of space, immune function is altered. This can pose problematic consequences for astronauts on deep space missions where medical intervention will be limited. Studying the unique environment of microgravity has its challenges, yet current research has uncovered immunological states that are probable during exploration missions. As microgravity-induced immune states are uncovered, novel countermeasure developments and personalized mitigation programs can be designed to improve astronaut health. This can also benefit immune-related monitoring programs for disorders on Earth. This is a comprehensive review, including gaps in knowledge, of simulated and spaceflight microgravity studies in human and rodent models.

Compensating three-dimensional field inhomogeneity in cold atom Efimov-state search by a time-averaged optical potential.

The Efimov effect and its universal property are of paramount importance in quantum few-body physics. Despite this, the predicted ground state Efimov resonance has not yet been observed in 39,40,41K-87Rb mixtures within the currently available observation window. Cooling atoms in the microgravity environment of outer space might overcome this limitation, whereas the residual curvature of the strong magnetic fields may result in significant atom leakage. In this work, we propose an optical method based on far-detuned time-averaged dipole potential to counteract the three-dimensional inhomogeneous field. The target intensity distribution can be conveniently obtained by modulating the central position of the quasi-1D print beam using acoustic optical modulators. Within a volume of 300 × 300 × 400µm3, the residual potential fluctuations can be reduced by two orders of magnitude to less than 100 pK. The proposed approach offers a realistic prospect of investigating the Efimov-type resonance in the 40K-87Rb Bose-Fermi mixture.

Experimental study on a dual compensation chamber loop heat pipe with a ceramic wick

The dual compensation chamber loop heat pipe (DCCLHP) has excellent application prospects in the future field of space thermal management. However, DCCLHP has some problems, such as startup difficulty with a small heat load and serious heat leakage from the back of the capillary pump. To ensure the reliable startup and efficient heat transfer of DCCLHP in the space microgravity environment, a kind of DCCLHP with an eccentric structure of silicon nitride capillary wick was manufactured and verified. The experimental results show that the DCCLHP can be started with a 2 W small heat load, with two different starting conditions. The heat transfer capacity exceeds 450 W in the 2.0 m heat transfer range. The starting temperature overshoot of DCCLHP presents an inverted “V” shape relationship with the heat load. The smaller the temperature difference between the two compensation chambers is, the heat transfer performance of DCCLHP will be promoted. This study has significant reference value for applying DCCLHP in space microgravity thermal management.

Clustering of charged colloidal particles in the microgravity environment of space

We conducted a charge–charge clustering experiment of positively and negatively charged colloidal particles in aqueous media under a microgravity environment at the International Space Station. A special setup was used to mix the colloid particles in microgravity and then these structures were immobilized in gel cured using ultraviolet (UV) light. The samples returned to the ground were observed by optical microscopy. The space sample of polystyrene particles with a specific gravity ρ (=1.05) close to the medium had an average association number of ~50% larger than the ground control and better structural symmetry. The effect of electrostatic interactions on the clustering was also confirmed for titania particles (ρ ~ 3), whose association structures were only possible in the microgravity environment without any sedimentation they generally suffer on the ground. This study suggests that even slight sedimentation and convection on the ground significantly affect the structure formation of colloids. Knowledge from this study will help us to develop a model which will be used to design photonic materials and better drugs.

Bacterial Virulence and Prevention for Human Spaceflight.

With the advancement in reusable rocket propulsion technology, space tourist trips into outer space are now becoming a possibility at a cost-effective rate. As such, astronauts will face a host of health-related challenges, particularly on long-duration space missions where maintaining a balanced healthy microbiome is going to be vital for human survival in space exploration as well as mission success. The human microbiome involves a whole list of micro-organisms that reside in and on the human host, and plays an integral role in keeping the human host healthy. However, imbalances in the microbiome have been directly linked to many human diseases. Research findings have clearly shown that the outer space environment can directly affect the normal microbiome of astronauts when the astronaut is exposed to the microgravity environment. In this study, we show that the simulation of microgravity on earth can mimic the outer space microgravity environment. Staphylococus aureus (S. aureus) was chosen for this study as it is an opportunistic pathogen, which is part of the normal human skin microflora and the nasal passages. This study's results show that S. aureus proliferation was significantly increased under a microgravity environment compared to Earth's gravity conditions, which complements previous work performed on bacteria in the outer space environment in the International Space Station (ISS). This demonstrates that this technology can be utilised here on Earth to mimic the outer space environment and to study challenging health-related questions. This in return saves us the cost on conducting experiments in the ISS and can help advance knowledge at a faster rate and produce countermeasures to mitigate the negative side effects of the hostile outer space environment on humans.

Design and Robustness Analysis of a Wave-Based Controller for Tethered Towing of Defunct Satellites

A microgravity environment in space, the elasticity of the tether, and complex flexible appendages make the tethered-towing system a nonlinear and underactuated system, which is sensitive and difficult to stabilize. This letter develops a controller based on wave propagation for tethered towing of defunct satellites, and carries out a robustness analysis of the controller via numerical simulation.

Tapered LADs: Acquiring Cryogenic Liquid Propellants in Deep Space

To carry out complex manoeuvres such as orbit insertion, large spacecraft on long voyages must carry tanks of liquid propellants, kept at ultra-cold temperatures. In existing designs, however, heat leaking into these tanks can form unwanted vapour bubbles in the channels required to extract their contents – which are especially difficult to remove in the microgravity environment of deep space. In their research, a team at the Southwest Research Institute presents a simple solution to this problem – through which the sides of these extraction channels are tapered, allowing vapour bubbles to escape. Results from recent microgravity testing of this technology could lead to exciting new opportunities for future space missions.

Importance of Right Nutrition for the Astronauts of Deep Space

Essential food requirements for space food systems include food safety, palatability, safety, stability, variety, usability, and reliability. The space station administration always gives astronauts access to nutritious food like fruits, vegetables, and certain processed foods as a regular diet. The gravitational impacts are significantly reduced in a microgravity environment in deep space. As a result of microgravity, the eating implements like wise float away. The beverage packaging for the international space station is made of laminated foil and plastic. The article mainly talked about the food system engineering facilities and the classifications of space food according to their processing. The article also highlighted the standard menu in a space shuttle for American, Russian, and Chinese astronauts according to a pre-planned diet. There are various uses of food under the food processing system in the space shuttle, such as preparation and selection of food, planning, and serving of food, etc. Similarly, it is essential for extended shelflife food for Indian astronauts. Proper nutrition and food safety are critical for all astronauts to cope with deep space environments.

Microgravity environment grown crystal structure information based engineering of direct electron transfer type glucose dehydrogenase

The heterotrimeric flavin adenine dinucleotide dependent glucose dehydrogenase is a promising enzyme for direct electron transfer (DET) principle-based glucose sensors within continuous glucose monitoring systems. We elucidate the structure of the subunit interface of this enzyme by preparing heterotrimer complex protein crystals grown under a space microgravity environment. Based on the proposed structure, we introduce inter-subunit disulfide bonds between the small and electron transfer subunits (5 pairs), as well as the catalytic and the electron transfer subunits (9 pairs). Without compromising the enzyme’s catalytic efficiency, a mutant enzyme harboring Pro205Cys in the catalytic subunit, Asp383Cys and Tyr349Cys in the electron transfer subunit, and Lys155Cys in the small subunit, is determined to be the most stable of the variants. The developed engineered enzyme demonstrate a higher catalytic activity and DET ability than the wild type. This mutant retains its full activity below 70 °C as well as after incubation at 75 °C for 15 min – much higher temperatures than the current gold standard enzyme, glucose oxidase, is capable of withstanding.

Skin microbiome considerations for long haul space flights.

Dysbiosis of the human skin microbiome has long been associated with changes to the pH of the skin, dermal immune function and chronic skin conditions. Dermatological issues have been noted as the most prevalent medical presentation in the microgravity environment of space. The change in gravitational forces has been implicated in human immuno-suppression, also impacted by changes in the gastrointestinal-skin axis and its impact on Vitamin D metabolism, altered microbial gene expression in resident flora (leading changes in biofilm formation) and increased virulence factors in potential pathogens. There are also other stressors to the skin microbiome unique to space travel, including increased exposure to radiation, prolonged periods of dry washing technique, air quality and changes in microbe replication and growth parameters. Optimal microbiome health leads to enhanced skin barrier manufacture and maintenance, along with improved skin immune function and healing. In a microgravity environment expected to be experienced during long space flights, disruptions to the skin microbiome, coupled with increased virulence of pathological viruses and bacteria has implications for holistic skin health, astronaut cognitive function and mental health, and is coupled with slowed rates of wound healing. Scenario management for holistic skin health and restoration of microbiome homeostasis on long space flights require consideration.

Low-frequency vibration control of two flexible appendages using a joint with actively tunable stiffness

Low-frequency and large-amplitude vibration of flexible appendages in space can be induced when a spacecraft performs attitude maneuvers and thermal alternations during orbit operation. In this paper, a novel joint mechanism combined with a semi-active method for variable stiffness control is proposed to suppress the low-frequency vibrations of flexible jointed appendages. The variable stiffness of the joint is derived from the linear relationship between its output torque and rotation angle when direct current (DC) power is applied to the coils. Based on the Lagrange equation and the assumed mode method, the coupling dynamic relationships of the active joint and two flexible appendages are established, and semi-active vibration control simulations are performed. A ground experimental platform is built to simulate the microgravity environment in space. The frequency shift effect of rigid body motion and elastic vibration under impact disturbance are investigated. In addition, the effect of variable stiffness control on the elastic deformation of flexible appendages is studied. The simulation and experimental results indicated that the proposed method can control both the rigid body motion of the system and the elastic vibration of the appendages. It has been found that the major frequency bandwidth of the interference signal is within 0.3–1.0 Hz with a substantial vibration attenuation of 1.82–16.62 dB for the joint and 4.86–11.48 dB for the flexible appendages.

Muscle synergies of multidirectional postural control in astronauts on Earth after a long-term stay in space.

Movements of the human biological system have adapted to the physical environment under the 1-g gravitational force on Earth. However, the effects of microgravity in space on the underlying functional neuromuscular control behaviors remain poorly understood. Here, we aimed to elucidate the effects of prolonged exposure to a microgravity environment on the functional coordination of multiple muscle activities. The activities of 16 lower limb muscles of 5 astronauts who stayed in space for at least 3 mo were recorded while they maintained multidirectional postural control during bipedal standing. The coordinated activation patterns of groups of muscles, i.e., muscle synergies, were estimated from the muscle activation datasets using a factorization algorithm. The experiments were repeated a total of five times for each astronaut, once before and four times after spaceflight. The compositions of muscle synergies were altered, with a constant number of synergies, after long-term exposure to microgravity, and the extent of the changes was correlated with the increased velocity of postural sway. Furthermore, the muscle synergies extracted 3 mo after the return were similar in their activation profile but not in their muscle composition compared with those extracted in the preflight condition. These results suggest that the modularity in the neuromuscular system became reorganized to adapt to the microgravity environment and then possibly reoptimized to the new sensorimotor environment after the astronauts were reexposed to a gravitational force. It is expected that muscle synergies can be used as physiological markers of the status of astronauts with gravity-dependent change.NEW & NOTEWORTHY The human neuromuscular system has adapted to the gravitational environment on Earth. Here, we demonstrated that prolonged exposure to a microgravity environment in space changes the functional coordination of multiple muscle activities regarding multidirectional standing postural control. Furthermore, the amount of change led to a greater regulatory balancing activity needed for postural control immediately after returning to Earth and differences in muscular coordination before space flight and 3 mo after the return to Earth.

Backstepping sliding mode control strategy of non-contact 6-DOF Lorentz force platform

With the development of aerospace technology, more and more scientific activities are carried out in the universe. Due to the microgravity environment of space, the control of the 6-DOF platform is different from those on the earth. First, a virtual prototype model of the 6-DOF non-contact platform was built in ADAMS. The dynamics model was developed based on the Newton–Euler method. Then, the 6-DOF backstepping sliding mode controller and disturbance observer were designed in MATLAB/Simulink. Finally, by combining the virtual prototype model in ADAMS and the control system in MATLAB, the co-simulation model was proposed. According to the simulation results, the 6-DOF backstepping sliding mode controller can well complete the positioning, 3D trajectory tracking, and vibration isolation tasks of non-contact 6-DOF platform. Quantitatively, the spatial error of backstepping sliding mode controller’s 3D trajectory tracking is only 50% of the ordinary sliding mode control and it is 20% of the nonlinear propotional-derivative-integral.

Simulation analysis of liquid sloshing separation in spacecraft with tank based on SPH method

<p indent=0mm>The separation of spacecraft in orbit is based on multibody dynamics in a space microgravity environment, while liquid sloshing is studied based on complex nonlinear dynamics. In this study, the smoothed particle hydrodynamics (SPH) method was used to simulate liquid sloshing with a free surface in a spacecraft tank, and the separation dynamic model of the spacecraft and liquid fuel was established. Through the analysis of spacecraft separation dynamics and fluid–structure coupling dynamics, the problem of the influence of sloshing of the liquid in the fuel tank on spacecraft separation attitude was solved. The interference force and torque of liquid sloshing on the spacecraft can be obtained from the model fluid–structure coupling dynamics calculation. The separation attitude of spacecraft with liquid sloshing in the tank is different from that based on a rigid body assumption. The liquid levels affect the calculation results of spacecraft separation attitude, interference force, and torque. The analysis results provide a reference for the optimization design and separation safety design of the spring separation mechanism and improve the reliability of spacecraft attitude control design.

NUMERICAL STUDY ON THERMAL DESTRATIFICATION IN LARGE SCALE HYDROGEN PROPELLANT TANK IN SPACE BY JET INJECTION UNDER ZERO GRAVITY CONDITION1)

Liquid Hydrogen plays a vital role in the future energy system as a space propellant, but it is sensitive to heat leakage from the environment because of its low boiling point and easy evaporation. On the other hand the buoyancy convection in the space microgravity environment is significantly reduced. When there is local heat leakage on the wall of the propellant tank, temperature stratification arises around the heat leakage source causing local overheating. It seriously affects the multiphase heat and mass transfer in the propellant tank which induces the tank pressure rise and jeopardize the structural safety of the system. To prevent the tank pressure from rising above the design of limits, venting or active pressure control techniques must be implemented. The cryogenic jet mixing is an effective means to suppress temperature stratification. The cryogenic fluid is mixed with the fluid inside the tank through a jet nozzle to reduce the local high temperature and achieve uniform temperature. In present paper, the thermal stratification phenomenon caused by the local heat leakage under microgravity condition was numerically simulated by using a fully filled two-dimensional large scale tank model. This paper mainly analyzes the suppression and elimination of local thermal stratification caused by heat leakage near the bottom of the storage tank and the outlet connecting section. The influence of different cryogenic jet mixing conditions on eliminating the temperature stratification effect is analyzed. The results show that the position of jet nozzle has no obvious effect on the elimination of thermal stratification inside the tank when the circular jet nozzle is used and the cryogenic jet condition is the same. When the jet nozzles are located in the same relative position inside the tank and the incident flow rate is the same, the circular jet nozzles have more concentrated flow direction, the flow field in the tank evolves faster, so the thermal stratification elimination effect is better than the hemispherical jet nozzles.