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

Recent advancements in stem cell biology, coupled with developments in space exploration, have opened new avenues for regenerative medicine. Microgravity environments in space induce significant physiological changes in the human body, such as muscle atrophy, decreased bone density, and immune system impairments, mimicking accelerated aging and chronic disease progression. These conditions offer a unique opportunity to study stem cell behavior, proliferation, and differentiation, which occur at a faster pace in space compared to Earth. The three-dimensional (3D) microgravity environment provides a more accurate representation of the human body’s natural state than traditional two-dimensional culture systems, fostering enhanced stem cell development. Among the various stem cells studied in space, mesenchymal stem cells (MSCs) have shown promise for therapeutic applications, including the treatment of stroke, cancer, and neurodegenerative diseases. Research aboard the International Space Station (ISS) has demonstrated that MSCs maintain their properties, proliferate, and differentiate under microgravity conditions, offering potential for future therapies. Additionally, MSCs exhibit resistance to space radiation, protecting astronauts from its harmful effects by promoting tissue repair and releasing regenerative factors. This radiation resistance, coupled with cryopreservation techniques, enables MSCs to be used in long-duration space missions. The ongoing research on MSCs in space not only supports astronaut health but also holds the potential to revolutionize regenerative medicine on Earth. By understanding how microgravity influences stem cell behavior, scientists are uncovering critical insights into tissue repair and cell function, paving the way for innovative treatments for aging-related diseases and other medical conditions. These findings highlight the broader implications of space-based stem cell research for advancing human health both in space and on Earth.

Flammability limit of thin flame retardant materials in microgravity environments

T-Consciousness Fields (TCFs) are introduced as non-physical entities, with their effects initiated through the human mind. It is hypothesized that information transmitted via TCFs may influence the behavior of studied subjects. The present experiment aimed to investigate the effects of TCFs on cell cycle progression and ATP production in the HEK-293 cell line under both microgravity (MG) and Earth gravity (1G) conditions. To achieve this, cultured cells were exposed to TCFs for 24 hours following an initial 24-hour incubation period, under either microgravity (MG) conditions, simulated by clinostat rotation, or a standard Earth gravity (1G) environment. Untreated cells served as the control group. Flow cytometry was used to assess the distribution of cells across different phases of the cell cycle, and ATP concentration was measured by evaluating luciferase enzyme activity. The results showed a significant increase in the sub-G1 phase under microgravity (MG) conditions (p < 0.05), indicating elevated apoptosis. In contrast, TCFs-treated samples maintained sub-G1 levels comparable to those under Earth gravity (1G). Additionally, TCFs treatment significantly increased the S phase under MG (p < 0.05) and the G2 phase under 1G (p < 0.05). ATP concentrations were markedly reduced under MG in both treated and untreated samples compared to 1G (p < 0.05). However, in the clinostat environment, ATP levels in TCFs-treated samples were approximately twice as high as those in untreated controls (p < 0.05), whereas no significant difference was observed under 1G conditions. These findings suggest that the reduced sub-G1 phase in TCFs-treated samples under MG reflects apoptosis inhibition, while increased ATP levels and prolonged S phase indicate enhanced cellular efficiency under stress. The distinct outcomes under MG and 1G imply that the information transmitted by TCFs may vary depending on environmental conditions. Further studies are needed to elucidate the underlying mechanisms of TCF action.

The immune system is one of the most affected systems of the human body during space flight. The cells of the immune system are exceptionally sensitive to microgravity. Thus, serious concerns arise, whether space flight associated weakening of the immune system ultimately precludes the expansion of human presence beyond the Earth's orbit. For human space flight, it is an urgent need to understand the cellular and molecular mechanisms by which altered gravity influences and changes the functions of immune cells. The CELLBOX-PRIME (= CellBox-Primary Human Macrophages in Microgravity Environment) experiment investigated for the first time microgravity-associated long-term alterations in primary human macrophages, one of the most important effector cells of the immune system. The experiment was conducted in the U.S. National Laboratory on board of the International Space Station ISS using the NanoRacks laboratory and Biorack type I standard CELLBOX EUE type IV containers. Upload and download were performed with the SpaceX CRS-3 and the Dragon spaceship on April 18th, 2014 / May 18th, 2014. Surprisingly, primary human macrophages exhibited neither quantitative nor structural changes of the actin and vimentin cytoskeleton after 11 days in microgravity when compared to 1g controls. Neither CD18 or CD14 surface expression were altered in microgravity, however ICAM-1 expression was reduced. The analysis of 74 metabolites in the cell culture supernatant by GC–TOF–MS, revealed eight metabolites with significantly different quantities when compared to 1g controls. In particular, the significant increase of free fucose in the cell culture supernatant was associated with a significant decrease of cell surface–bound fucose. The reduced ICAM-1 expression and the loss of cell surface–bound fucose may contribute to functional impairments, e.g. the activation of T cells, migration and activation of the innate immune response. We assume that the surprisingly small and non-significant cytoskeletal alterations represent a stable “steady state” after adaptive processes are initiated in the new microgravity environment. Due to the utmost importance of the human macrophage system for the elimination of pathogens and the clearance of apoptotic cells, its apparent robustness to a low gravity environment is crucial for human health and performance during long-term space missions.

Microgravity as a biological tool to examine host-pathogen interactions and to guide development of therapeutics and preventatives that target pathogenic bacteria.

Microgravity (MG) during space flight has been known to cause adverse effect on bone quality. Data collected from studies done on spaceflights show loss of 1–1.6% bone mineral density (BMD) per space-flight-month[1]. Most BMD has been recorded in load-bearing bones [2]. Some studies has considered using drugs and different growth factors to maintain bone mass in microgravity conditions but it can be too expensive to maintain over longer periods of time besides the systematic effects of such treatments [3]. Considering the effects of microgravity are partially attributed to lack of mechanical force on bone tissue, which alters gene expression, reduction in transcription factors and growth factors. Furthermore, lack of gravity effects cell growth, proliferation, differentiation, cytoskeleton polymerization and cellular morphology [4, 5]. Thus to reverse these adverse effects on bone physiology, it is important to provide cells with mechanical stimulus which can provide essential mechanical signal for cells to counter the effects of microgravity. Ultrasound acoustic vibrations can be readily applied in, in vivo and human studies and has shown anabolic effects on osteopenic bone tissue [6]. Furthermore, ultrasound is a non-invasive and more target specific treatment relative to cyclic strain and vibration. The objective of this study is to see effects of low intensity pulsed ultrasound (LIPUS) on disused bone model and osteogenic activity of osteoblast cells cultures in simulated microgravity. This will help us understand that effects of ultrasound on microgravity and mechanotransduction pathway responsible for anabolic effect on bone cells.

Boiling heat transfer and bubble dynamics in microgravity

Ontogeny of plants under various gravity condition.

Chapter 2 - 3D printing and nanotechnology

6 - Advanced application of additive manufacturing in the footwear industry: from customized insoles to fully 3D-printed shoes

Fused filament fabrication (FFF) is a 3D printing technology that has been successfully demonstrated aboard the International Space Station (ISS), proving its suitability for space applications. In this study, we aimed to apply FFF to the 3D printing of recycled space beverage packaging, made of LDPE and a PET-Aluminum-LDPE (PAL) trilaminate. To minimize material waste and optimize the experimental process, we first conducted numerical simulations of additive manufacturing. Using Digimat-AM 2021.1 software, we analyzed residual stresses and warpage in an LDPE/PAL composite with a 10 wt% filler content, processed through the FFF technique. Three key printing parameters, including printing speed and infill pattern, were varied across different levels to assess their impact. Once the optimal combination of parameters for minimizing residual stresses and warpage was identified, we proceeded with the experimental phase, printing objects of increasing complexity to validate the correlation between numerical predictions and the 3D-printed models. The successful fabrication of all geometries under optimized conditions confirmed the numerical predictions, particularly the reduction in warpage and residual stress, validating the material’s viability for additive manufacturing. These findings support the potential application of the LDPE/PAL composite for in situ resource utilization strategies in long-term space missions.

A soft viscoelastic drop has dynamics governed by the balance between surface tension, viscosity, and elasticity, with the material rheology often being frequency dependent, which are utilized in bioprinting technologies for tissue engineering and drop-deposition processes for splash suppression. We study the free and forced oscillations of a soft viscoelastic drop deriving (1) the dispersion relationship for free oscillations, and (2) the frequency response for forced oscillations, of a soft material with arbitrary rheology. We then restrict our analysis to the classical cases of a Kelvin–Voigt and Maxwell model, which are relevant to soft gels and polymer fluids, respectively. We compute the complex frequencies, which are characterized by an oscillation frequency and decay rate, as they depend upon the dimensionless elastocapillary and Deborah numbers and map the boundary between regions of underdamped and overdamped motions. We conclude by illustrating how our theoretical predictions for the frequency-response diagram could be used in conjunction with drop-oscillation experiments as a “drop vibration rheometer”, suggesting future experiments using either ultrasonic levitation or a microgravity environment.

The benefits of crystallization in a microgravity environment have been documented. Herein, we update the community on the results of a retrospective meta-analysis and data curation of 507 unique crystallization experiments that have been disseminated in the literature over a broad diversity of substrates. The analysis variables in the dataset that were evaluated include individual success metrics such as size, structural improvement, improved uniformity, increased resolution limit, and improved mosaicity. The overall databases were evaluated over time and by molecular complexity. Compared to ground experiments, crystals grown in a microgravity environment continue to show improvement across all metrics evaluated. The retrospective analysis demonstrates that success rates of crystallization experiments in microgravity improved over time. There also seems to be no correlation between complexity of molecule, using molecular weight as a surrogate for complexity, and successful crystallization under microgravity conditions. The microgravity environment provides improvement to crystal fabrication across metrics utilized for evaluation and molecular types, and the datasets utilized for this investigation are excellent tools for this evaluation.

Development of a small He II cryostat with optical windows for a microgravity experiment

The solar panels installed on a CubeSat are considered the main energy source of a nanosatellites. The deployment mechanism of a solar panel must be analyzed and tested extensively. Any suggested solar panel design should present a low vibrating free spinning deployment mechanism. This paper examines various types of solar panels to reach a conclusion of the efficient design when deployed on a 1U or 2U unit. However, calculations, analysis, simulations do not always give an extensive picture of how the satellite shall behave during deployment. Thus, testing in a microgravity environment gives a more accurate answer of how the satellite shall behave. In our work, various solar panels mechanisms are developed and eventually tested in microgravity. The first accordion structure for a 1U structure is tested in a microgravity environment through a parabolic flight with the National Research Council Falcon 20 aircraft. The results are recorded and analyzed to optimize the next design. The second design is based on a drag-sail mechanism for a 2U structure. The design is improved upon the first experiment results for the next parabolic flight. The simulated amount of power generated in orbit is also a main factor in our evaluation.