Microgravity Conditions Research Articles

Effects of simulated microgravity on colorectal cancer organoids growth and drug response

Cellular and molecular dynamics of human cells are constantly affected by gravity. Alteration of the gravitational force disturbs the cellular equilibrium, which might modify physiological and molecular characteristics. Nevertheless, biological responses of cancer cells to reduced gravitational force remains obscure. Here, we aimed to comprehend not only transcriptomic patterns but drug responses of colorectal cancer (CRC) under simulated microgravity. We established four organoids directly from CRC patients, and organoids cultured in 3D clinostat were subjected to genome wide expression profiling and drug library screening. Our observations revealed changes in cell morphology and an increase in cell viability under simulated microgravity compared to their static controls. Transcriptomic analysis highlighted a significant dysregulation in the TBC1D3 family of genes. The upregulation of cell proliferation observed under simulated microgravity conditions was further supported by enriched cell cycle processes, as evidenced by the functional clustering of mRNA expressions using cancer hallmark and gene ontology terms. Our drug screening results indicated an enhanced response rate to 5-FU under conditions of simulated microgravity, suggesting potential implications for cancer treatment strategies in simulated microgravity.

Development of 6DOF Hardware-in-the-Loop Ground Testbed for Autonomous Robotic Space Debris Removal

This paper presents the development of a hardware-in-the-loop ground testbed featuring active gravity compensation via software-in-the-loop integration, specially designed to support research in autonomous robotic removal of space debris. The testbed is designed to replicate six degrees of freedom (6DOF) motion maneuvering to accurately simulate the dynamic behaviors of free-floating robotic manipulators and free-tumbling space debris under microgravity conditions. The testbed incorporates two industrial 6DOF robotic manipulators, a three-finger robotic gripper, and a suite of sensors, including cameras, force/torque sensors, and tactile tensors. Such a setup provides a robust platform for testing and validating technologies related to autonomous tracking, capture, and post-capture stabilization within the context of active space debris removal missions. Preliminary experimental results have demonstrated advancements in motion control, computer vision, and sensor fusion. This facility is positioned to become an essential resource for the development and validation of robotic manipulators in space, offering substantial improvements to the effectiveness and reliability of autonomous capture operations in space missions.

Effect of Microgravity on Rare Earth Elements Recovery by Burkholderia cepacia and Aspergillus niger

Rare earth elements (REEs) are indispensable in modern industry and technology, driving an urgent demand for innovative, eco-friendly recovery technologies. As space exploration advances, the impact of microgravity on microorganisms has become a focal point, yet the effects on microbial growth and REEss recovery remain uncharted. This study investigates the biosorption of REEs by Burkholderia cepacia (B. cepacia) and Aspergillus niger (A. niger) from a mixed solution containing La, Ce, Pr, Nd, Sm, Er, and Y under varying initial concentrations, pH levels, and microgravity conditions. We observed that the medium’s pH rose with B. cepacia and fell with A. niger when cultured in normal gravity conditions, suggesting distinct metabolic responses. Notably, microgravity significantly altered microbial morphology and metabolite profiles, significantly enhancing REEs recovery efficiency. Specifically, the recovery of B. cepacia of Ce and Pr peaked at 100%, and A. niger achieved full recovery of all tested REEs at pH 1.5 (suboptimal growth conditions). This study pioneers the application of biosorption for the recovery of REEs in microgravity conditions, presenting a promising strategy for future resource exploitation by space biomining.

Redefining space pharmacology: bridging knowledge gaps in drug efficacy and safety for deep space missions

The space environment is incredibly hostile, and humans are vulnerable in such conditions. Astronauts encounter various stress factors during a space journey, including radiation, microgravity, forceful acceleration during launch, altered magnetic fields, and confinement. These stressors significantly impact the human body homeostasis, leading to physio-pathological adaptations, loss of bone density, muscle atrophy, cardiovascular deconditioning, alterations in liver function, vestibular adaptations, and immune system dysregulation. These alterations can potentially influence drug pharmacokinetics and pharmacodynamics, affecting the efficacy and safety of medications administered to astronauts. Due to the limited number of studies on pharmaceuticals conducted in microgravity conditions, it’s challenging to assess the effectiveness and stability of these medications during spaceflight. The objective of the present work is to compare the state-of-the-art knowledge on PK/PD changes and factors likely to affect them during spaceflight, with the subjective perception of the problem by a collection of separate interviews conducted with seven experts in the field. The interviewees were chosen as “experts,” i.e., representatives in a specific discipline, who possess knowledge and experience in space pharmacology, physiology, or biology. Thus, our panel included astronauts, space surgeons, and scientists aiming to bridge the lack of experimental data in the literature. Each interview explores assorted aspects of space physiology and pharmacology, including drug use and storage onboard the ISS; notable consideration has arisen regarding the current research gaps and future space expeditions. All the interviews were held remotely using online conferencing software. None of the interviewees could provide a comprehensive overview regarding potential changes in drugs PK/PD in microgravity conditions. Further, any medication brought on board (whether as part of an astronaut’s medical kit or stored in the ISS pharmacy) is destroyed, thereby suppressing the possibility of analyzing any degradation products resulting from long-term exposure to microgravity and radiation. According to these results, the use of drugs without understanding how they are genuinely absorbed, distributed, metabolized, and excreted in microgravity conditions is concerning, posing risks for drug effectiveness. Conducting genotyping and phenotyping on astronauts would be beneficial for developing personalized pharmacological countermeasures for each astronaut and anticipating expected drug metabolism changes during space missions.

Effect of Microgravity on the Metal Droplet Transfer and Bead Characteristics in the Directed Energy Deposition-Arc Process

Abstract Directed energy deposition-arc (DED-arc) is a viable method of metal 3D printing for manufacturing in-space under microgravity conditions. This study investigates the effect of reduced gravity on the droplet transfer in a gas metal arc welding (GMAW)-based DED-arc process. Single bead deposited using GMAW welding process under microgravity and standard terrestrial gravity (1 g) are compared. Microgravity was simulated in a drop tower where the experimental capsule was subjected to 2.5 s of free-fall. The experimental setup for GMAW welding process, including high-speed cameras and sensors, was present within the experimental capsule. Droplet frequency and diameter were measured and compared between microgravity and 1 g using the images obtained. Further, the impact of reduced gravity on weld bead geometry and the distribution of gas porosity was investigated. Microhardness analysis was also conducted on both 1 g and reduced gravity samples to assess variations in material hardness. A statistically significant difference in droplet diameter and frequency was found. This difference is attributed to the reduction in gravitational force. Upon analyzing the weld bead geometry, noticeable variations are detected in the contact angles and the reinforcement of beads formed under different gravity conditions. These differences are attributed to alterations in convection within the molten weld pool. The blowhole analysis revealed a noticeable trend, wherein reduced gravity facilitated the coalescence of gas porosity, resulting in larger diameters due to alterations in weld pool convection. There were no statistically significant changes observed in both microhardness and surface finish.

Exploring the effects of simulated microgravity on esophageal cancer cells: insights into morphological, growth behavior, adhesion, and genetic damage.

The exploration of microgravity has garnered substantial scholarly attention due to its potential to offer unique insights into the behavior of biological systems. This study presents a preliminary investigation into the effects of simulated microgravity on esophageal cancer cells, examining various aspects such as morphology, growth behavior, adhesion, inhibition rate, and DNA damage. To achieve this, a novel microgravity simulator named "Gravity Challenge" was utilized for its effectiveness in minimizing external influences that could compromise microgravity conditions. The international cell line SK-GT-4 was utilized as the focal point of this investigation. Results revealed noticeable alterations in the growth behavior of cancer cells following exposure to simulated microgravity for 24 h, characterized by a loss of adhesion properties compared to control cells. Concurrently, cell viability exhibited a decline, as evidenced by cytotoxicity testing. Furthermore, the comet assay test demonstrated that cells subjected to microgravity simulation experienced a higher incidence of DNA damage compared to their control counterparts. In conclusion, this comprehensive examination of the impact of simulated microgravity on esophageal cancer cells extends beyond morphological changes, delving into genetic implications through observed DNA damage. The diminished vitality of cells under microgravity conditions underscores the multifaceted effects on cellular behavior in response to environmental variations. These findings represent a significant step towards understanding the dynamics of cancer cells, laying the groundwork for future research aimed at identifying potential therapeutic strategies for this disease.

HFE-7100 spray cooling under microgravity: Liquid film dynamics and heat transfer

Spray cooling under microgravity is not only motivated by space applications but also by the essential pursuit of the exploration spirit facing the unknown. This study was the first series of scientific experiments conducted at the China New Microgravity Experiment Facility with Electromagnetic Launch. In this study, the liquid film dynamics and heat transfer characteristics of HFE-7100 spray, including liquid film morphology, wetted area, equivalent diameter, and velocity under different inlet pressures and heat fluxes, were quantitatively captured on smooth and rough silicon surfaces under microgravity. Several classic scenarios of liquid films, including spreading, bifurcating, bridging, fusiform, tadpole-shaped, and isolated liquid film, were recognized for the first time. The morphologies of the liquid films and the heat transfer performance under smooth and rough surfaces showed insignificant differences under normal and microgravity conditions. In addition, the dimensionless groups (Weber number and Reynolds number) were updated corresponding to approximately 92.4 % of the total We samples and approximately 96.4 % of the total Re samples ranging from 0.01 to 1 and 10 to 300, respectively, regardless of the different coolants (HFE-7100 and HFE-7000), pressures, nozzle-to-surface heights, heat fluxes, surface conditions, orientations, and gravities (1 g and µg).

3D Printing of solvent-free PEO-Polyolefin solid polymer electrolyte by Fused Filament Fabrication

ABSTRACT 3D printing of energy storage systems is at the heart of In-Space Manufacturing strategy. Within this context, Li-ion polymer batteries printing through Fused Filament Fabrication (FFF) is envisaged. This study is devoted to optimising the extruded solid polymer electrolyte filament properties. As the poly(ethylene oxide) (PEO) – lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) electrolyte offers the best Li+ conductivities but suffers from poor mechanical behaviour, poly(propylene) (PP) is added to ensure filament printability. An exhaustive investigation highlights the impact of the PEO molar weight and the LiTFSI and PP proportions. Fine-tuning these parameters alters molten phase viscosity, which affects the electrolyte morphology and ionic conductivity. Best formulations feature a co-continuous structure that provides effective mechanical reinforcement and exhibits the best ionic conductivity reported so far for an FFF-printed solvent-free polymer electrolyte of 1.2 × 10−4 S.cm−1 at 70°C. Therefore, it opens the way towards polymer battery printing, on the Earth and in microgravity conditions.

281 - An Examination of Mouse Bladder Function in Microgravity Conditions: Insights from Space Environments

281 - An Examination of Mouse Bladder Function in Microgravity Conditions: Insights from Space Environments

Use of magnetic fields to impact glass-transition and crystallization during manufacturing of ZBLAN optical fibers

ZBLAN (ZrF4-BaF2-LaF3-AlF3-NaF) is the most stable glass among the Heavy Metal Fluoride (HMF) family and has a wide range of applications in medical industry, telecommunication, IR transmission, among others. But, due to crystal formation while manufacturing of ZBLAN fiber its theoretical minimum loss has not been achieved yet. Some techniques such as high cooling rate and microgravity conditions have been utilized to reduce the crystal formation but are challenging to implement during manufacturing of these fibers. Alternatively, magnetic field (MF), also a body force like gravity, is expected to influence the crystal formation mechanism and glass kinetics. In this work, ZBLAN glass is processed under magnetic fields of various intensities while simulating fiber drawing manufacturing process conditions. Then, the processed ZBLAN is analyzed using Differential Scanning Calorimetry (DSC) at varying scanning rates. Various glass kinetics parameters such as activation energy, fragility, and preferred crystallization mechanism in terms of Avrami parameter (n) have been analyzed. The glass transition temperature (Tg) increases for a given sample as scanning rate (β) increases. Samples processed under varying magnetic fields, at the same scanning rate, displayed higher glass transition temperatures. Also, when the magnetic field increases, the activation energy required for glass transition decreases, and the fragility index (m) decreases. There is also a preference for surface crystallization over volume crystallization. These results encourage application of magnetic fields for reducing crystal formation while processing ZBLAN glass.

Study of the features of concentration inhomogeneities during the on ground-based processing of the space experiment of the Ge(Ga) crystals growth

The article presents the results of the preparation and ground testing of the space experiment for growing Ge (Ga) crystals, planned on board the multifunctional laboratory module as part of the ISS RS. Under the conditions simulating microgravity, the features of the formation of concentration inhomogeneity in the form of growth bands when growing crystals under various thermal conditions (in the presence or absence of a free melt surface (Marangoni convection)), as well as when changing technological parameters (variations in growth rate) were investigated. Based on the obtained results of metallographic and electrophysical studies, conclusions were made about the peculiarities of the influence of the technological parameters of the crystallization process on the structural perfection of the grown crystals under microgravity conditions

Gravitational effects on optical lens fabrication: First insides on Earth- and microgravity experiments

Abstract Understanding the effects of gravity on manufacturing processes is a pioneering extension of the process parameter space used to date. Until now, the improvement of manufacturing technologies has mainly focused on process parameters such as temperature, pressure, and material composition, as access to variable gravity environments is limited. The Einstein-Elevator opens up new possibilities for the variation of these process parameters and the development of in-space manufacturing technologies. Together with the research of innovative production processes for optical components within the PhoenixD Cluster of Excellence, this creates an entirely new field of research. The research presented here focuses on investigating gravity's effects on dispensed optical lens production. Using a jet dispenser, sessile droplets are produced during a flight phase in the Einstein-Elevator and cured directly by UV polymerization. As part of this study, optical lenses were produced and compared under microgravity and Earth's gravitational conditions. Geometric properties such as height and contact angle of the lenses produced were analyzed. It was found that lenses fabricated under microgravity have a larger contact angle than those fabricated under Earth gravity. Similarly, the height increases with decreasing gravity. These results are consistent with the theoretical assumptions described, although generalized theories to describe the morphology of a sessile droplet are not yet available. The case study findings on the influence of gravity as a process parameter on drop morphology represent a fundamental improvement for additive manufacturing technologies, especially for in-space manufacturing.

Ultrasonic Levitation as a Handling Tool for In-Space Manufacturing Processes

Abstract 3D printing is one of the key technologies in space exploration. The disparity in gravitational forces between Earth and space presents both challenges and opportunities with regard to material handling. This article examines the potential of employing ultrasonic levitation as a handling tool for substrate-free additive manufacturing processes in microgravity environments. Through preliminary experiments, we demonstrate the feasibility of manipulating polymer powders using acoustic fields while concurrently melting the levitated material. Subsequent experiments conducted in our drop tower facility confirm our ability to manipulate particles with acoustic traps under microgravity conditions. Building upon these findings, we outline plans to further advance our research using an expanded acoustic levitation system capable of three-dimensional object manipulation. Our objectives include moving and orienting large components beyond the wavelength limit in microgravity, manipulating granular raw material while melting it in proximity to the print part, and achieving a semi-continuous fusion of print material with the print part. Therefore, we present an intelligent control strategy based on the results of a digital twin simulation. Furthermore, we utilize a stereo camera combined with computer vision as feedback for the control system to ensure precise handling of the manipulated objects and particles. This study represents a significant advance toward the realization of efficient substrate-free additive manufacturing processes in microgravity environments, with potential applications for in-space manufacturing. Ultimately, this could result in long-term space missions becoming less reliant on supply deliveries, thus reducing cost and additionally enabling faster response to unforeseen issues.

Spirulina platensis components mitigate bone density loss induced by simulated microgravity: A mechanistic insight

In microgravity conditions, the consumption of Spirulina platensis (SP) as a renewable food source shows promise in mitigating osteoporosis due to its high nutritional content photosynthetic efficiency, environmental adaptability and positive effects on bone density, though the exact bioactive components and mechanisms remain unclear. Using a hindlimb suspension (HLS) model, this study investigated SP components: proteins (SPP), polysaccharides (SPS), lipids (SPL), and residue (SPR) on bone density and metabolism. Findings revealed that SPP and SPS significantly enhanced bone density and reduced oxidative stress. Activation of the FoxO3/Wnt/β-catenin pathway reduced FoxO3a expression and increased Wnt signaling molecules and β-catenin protein, boosting bone formation. Moreover, these components promoted beneficial gut bacteria like Turicibacter, reduced the Firmicutes-to-Bacteroidetes ratio, and enhanced SCFAs production, crucial for bone health. This study emphasized the potential of Spirulina nutrients in addressing space-induced osteoporosis and developing functional foods for long-term space missions.

Omics Studies of Specialized Cells and Stem Cells under Microgravity Conditions.

The primary objective of omics in space with focus on the human organism is to characterize and quantify biological factors that alter structure, morphology, function, and dynamics of human cells exposed to microgravity. This review discusses exciting data regarding genomics, transcriptomics, epigenomics, metabolomics, and proteomics of human cells and individuals in space, as well as cells cultured under simulated microgravity. The NASA Twins Study significantly heightened interest in applying omics technologies and bioinformatics in space and terrestrial environments. Here, we present the available publications in this field with a focus on specialized cells and stem cells exposed to real and simulated microgravity conditions. We summarize current knowledge of the following topics: (i) omics studies on stem cells, (ii) omics studies on benign specialized different cell types of the human organism, (iii) discussing the advantages of this knowledge for space commercialization and exploration, and (iv) summarizing the emerging opportunities for translational regenerative medicine for space travelers and human patients on Earth.

Improvement of heat treated spirulina proteins and their enzymatic hydrolysates on osteoporosis under simulated microgravity

In the space microgravity environment, bone loss poses a formidable health challenge for astronauts. Dietary intake of renewable food components offers a feasible approach to mitigate bone loss associated with primary osteoporosis, aligning with the demands of long-term space missions. Recent research has highlighted the potential of Spirulina in ameliorating osteoporosis, with thermal processing enhancing the protein bioavailability. This study investigates the effects of different heat-treated Spirulina proteins (SPP) and their enzymatic hydrolysates on osteoporosis using a hindlimb suspension model (HLS) in mice to simulate microgravity conditions. The results demonstrate that heat-treated SPP and enzymatic hydrolysates significantly preserve skeletal morphology, suppress bone resorption, and enhance bone density, with the microwave-treated SPP hydrolysate (MWSPPH) showing the most pronounced improvement effects. Mechanistic insights reveal that MWSPPH enhances bone health by modulating the FoxO/Wnt/β-catenin signaling pathway. Specifically, MWSPPH reduces the expression of FoxO and facilitates the accumulation of β-catenin, while also indirectly modulating osteoclast-related signaling by altering RANKL and RANK expression. It also beneficially increases beneficial gut microbiota and the production of short-chain fatty acids, thereby improving bone density, suggesting its potential as a dietary strategy for managing osteoporosis in space environments.

Human cranial bone-derived mesenchymal stem cells cultured under simulated microgravity can improve cerebral infarction in rats

The efficacy of transplanting human cranial bone-derived mesenchymal stem cells (hcMSCs) cultured under simulated microgravity (sMG) conditions has been previously reported; however, their effect on cerebral infarction remains unknown. Here, we examined the efficacy of transplanting hcMSCs cultured in an sMG environment into rat models of cerebral infarction. For evaluating neurological function, hcMSCs cultured in either a normal gravity (1G) or an sMG environment were transplanted in rats 1 day after inducing cerebral infarction. The expression of endogenous neurotrophic, axonal, neuronal, synaptogenic, angiogenic, and apoptosis-related factors in infarcted rat brain tissue was examined using real-time polymerase chain reaction and western blotting 35 days after stroke induction. The RNAs of hcMSCs cultured under 1G or sMG environments were sequenced. The results showed that neurological function was significantly improved after transplantation of hcMSCs from the sMG group compared with that from the 1G group. mRNA expressions of nerve growth factor, fibroblast growth factor 2, and synaptophysin were significantly higher in the sMG group than in the 1G group, whereas sortilin 1 expression was significantly lower. RNA sequencing analysis revealed that genes related to cell proliferation, angiogenesis, neurotrophy, neural and synaptic organization, and inhibition of cell differentiation were significantly upregulated in the sMG group. In contrast, genes promoting microtubule and extracellular matrix formation and cell adhesion, signaling, and differentiation were downregulated. These results demonstrate that hcMSCs cultured in the sMG environment may be a useful source of stem cells for the recovery of neurological function after cerebral infarction.

Experimental investigation and modelling of hydrodynamics and heat transfer in flow boiling in normal and microgravity conditions

The development of long-term space thermal management systems has informed research into the influence of gravity on boiling. This work explored the influence of gravity on the hydrodynamics and heat transfer of boiling flow. Experiments were carried out using two test loops each consisting of a 6 mmID transparent cylindrical test section. Upward (+1░g) and downward (−1░g) flow boiling experiments were carried out in the laboratory while microgravity (μg) experiments were carried out during a parabolic flight campaign. The results of flow visualisation showed significant influence of gravity on the flow patterns and the influence of gravity was generally limited to mass flux, G≤400kg/m2s and/or vapor quality, x≤0.35. In all three gravity conditions, the measured heat transfer coefficient was influenced by heat flux, mass flux and/or vapor quality. For liquid Reynolds number, Relo≤2000(G≤150kg/m2s) and boiling number Bo<0.002 the measured heat transfer coefficient was highest in −1g flow and lowest in μg flow but becomes comparable at Bo>0.002. A correlation for predicting microgravity heat transfer coefficient was proposed in this work and the proposed correlation predicted 100 % of the μg data in the current work within ±20%, predicted nearly 100 % of the μg data of Ohta et al. (2013) within ±30% and around 85 % of the μg data of Narcy (2014) within -20 % to +50 %. A correlation for predicting the gravity dependent regime as it relates to heat transfer coefficient in +1g and μg flows was also proposed in this work. The proposed criterium correctly predicted over 85 % of the gravity-dependent heat transfer coefficient in the current work and the works of Lebon et al. (2019), Narcy (2014), Ohta et al. (2013).

Exploring the Frontier of Space Medicine: The Nexus of Bone Regeneration and Astronautic Health in Microgravity Conditions

Exploring the Frontier of Space Medicine: The Nexus of Bone Regeneration and Astronautic Health in Microgravity Conditions

Mesenchymal stem cells arouse myocardial NAD+ metabolism to alleviate microgravity-induced cardiac dysfunction

After prolonged space operations, astronauts showed maladaptive atrophy within mostly left-ventricular myocardium, resulting in cardiac dysfunction. However, the mechanism of cardiac dysfunction under microgravity conditions is unclear, and the relevant prevention and treatment measures also need to be explored. Through simulating the microgravity environment with a tail suspension (TS) model, we found that long-term exposure to microgravity promotes aging of mouse hearts, which is closely related to cardiac dysfunction. The intravenous administration of adipose-derived mesenchymal stem cells (ADSCs) emerged preventive and therapeutic effect against myocardial senescence and the decline in cardiac function. Plasma metabolomics analysis suggests the loss of NAD+ in TS mice and motivated myocardial NAD + metabolism and utilization in ADSCs-treated mice, likely accounting for ADSCs' function. Oral administration of nicotinamide mononucleotide (NMN, a NAD + precursor) showed similar therapeutic effect to ADSCs treatment. Collectively, these data implicate the effect of ADSCs in microgravity-induced cardiac dysfunction and provide new therapeutic ideas for aging-related maladaptive cardiac remodeling.