Osteoporosis is a disease characterized by low bone mass and structural deterioration of bone tissue, leading to bone fragility and increased susceptibility to fractures. The microgravity of space creates an extreme environment that provides a model for osteoporosis in humans. This greatly accelerated form of osteopenia results in a 0.5-2% loss of bone mass per month. Rat models for this osteoporosis have been examined on many occasions, but STS-108 was the first Space Shuttle flight to use mice. Data reported to date indicate that spaceflight experiments with mice hold promise in predicting some spaceflight effects on humans. Due to the cost and infrequency of flights, ground-based models have been developed to mimic the deleterious effects of the microgravity environment. Hindlimb suspension is one such localized model. This model removes gravitational loading from the hindlimbs by suspending the animal by its tail to a guy wire that runs lengthwise across the cage. Because mice had not flown before STS-108, a direct comparison of this model’s ability to predict spaceflight results has not been examined. The objective of this research is to closely repeat the STS- 108 profile, with hindlimb suspension replacing spaceflight. This includes examining the ability of the protein osteoprotegerin, an osteoclast-inhibiting therapeutic, to mitigate the deleterious effects of skeletal unloading. It is expected that the results will lead to better understanding of the mechanisms of mineralization and bone remodeling to aid in development of countermeasures to prevent spaceflight induced osteoporosis and aid the treatment of osteoporosis here on earth.
Research Containing: Microgravity
Gravity is a constant unidirectional stimulus on Earth, and gravitropism in plants involves three phases: perception, transduction, and response. In shoots, perception takes place within the endodermis. To investigate the cellular machinery of perception in microgravity, we conducted a spaceflight study with Arabidopsis thaliana seedlings, which were grown in microgravity in darkness using the Biological Research in Canisters (BRIC) hardware during space shuttle mission STS-131. In the 14-day-old etiolated plants, we studied seedling development and the morphological parameters of the endodermal cells in the petiole. Seedlings from the spaceflight experiment (FL) were compared to a ground control (GC), which both were in the BRIC flight hardware. In addition, to assay any potential effects from growth in spaceflight hardware, we performed another control by growing seedlings in Petri dishes in standard laboratory conditions (termed the hardware control, HC). Seed germination was significantly lower in samples grown in flight hardware (FL, GC) compared to the HC. In terms of cellular parameters of endodermal cells, the greatest differences also were between seedlings grown in spaceflight hardware (FL, GC) compared to those grown outside of this hardware (HC). Specifically, the endodermal cells were significantly smaller in seedlings grown in the BRIC system compared to those in the HC. However, a change in the shape of the cell, suggesting alterations in the cell wall, was one parameter that appears to be a true microgravity effect. Taken together, our results suggest that caution must be taken when interpreting results from the increasingly utilized BRIC spaceflight hardware system and that it is important to perform additional ground controls to aid in the analysis of spaceflight experiments.
The Japan Aerospace Exploration Agency developed the mouse Habitat Cage Unit (HCU) for installation in the Cell Biology Experiment Facility (CBEF) onboard the Japanese Experimental Module (“Kibo”) on the International Space Station. The CBEF provides “space-based controls” by generating artificial gravity in the HCU through a centrifuge, enabling a comparison of the biological consequences of microgravity and artificial gravity of 1 g on mice housed in space. Therefore, prior to the space experiment, a ground-based study to validate the habitability of the HCU is necessary to conduct space experiments using the HCU in the CBEF. Here, we investigated the ground-based effect of a 32-day housing period in the HCU breadboard model on male mice in comparison with the control cage mice. Morphology of skeletal muscle, the thymus, heart, and kidney, and the sperm function showed no critical abnormalities between the control mice and HCU mice. Slight but significant changes caused by the HCU itself were observed, including decreased body weight, increased weights of the thymus and gastrocnemius, reduced thickness of cortical bone of the femur, and several gene expressions from 11 tissues. Results suggest that the HCU provides acceptable conditions for mouse phenotypic analysis using CBEF in space, as long as its characteristic features are considered. Thus, the HCU is a feasible device for future space experiments.
Contribution to the benchmark for ternary mixtures: Measurement of diffusion and Soret coefficients in 1,2,3,4-tetrahydronaphthalene, isobutylbenzene, and dodecane onboard the ISS
The paper is devoted to processing the data of DCMIX 1 space experiment. In this experiment, the Optical digital interferometry was used to measure the diffusion and Soret coefficients in the ternary mixture of 1,2,3,4-tetrahydronaphthalene, isobutylbenzene and n-dodecane at mass fractions of 0.8/0.1/0.1 and at 25 degrees C. The raw interferometric images were processed to obtain the temporal and spatial evolution of refractive indices for two laser beams of different wavelengths. The method for extracting the diffusion and thermal diffusion coefficients originally developed for optical beam deflection was extended to optical digital interferometry allowing for the spatial variation of refractive index along the diffusion path. The method was validated and applied to processing the data for Soret and diffusion steps in 5 experimental runs. The obtained results for the Soret coefficients and one of the eigenvalues of diffusion matrix showed acceptable agreement within each step. The second eigenvalue was not determined with sufficient accuracy.
Complex Plasma Research under Microgravity Conditions: PK-3 Plus Laboratory on the International Space Station
Complex (dusty) plasmas are composed of weakly ionised gas and charged microparticles and represent the plasma state of soft matter. Due to the ”heavy” component — the microparticles — and the low density of the surrounding medium, the rarefied gas and plasma, it is necessary to perform experiments under microgravity conditions to cover a broad range of experimental parameters which are not available on ground. The investiga- tions have been performed onboard the International Space Station (ISS) with the help of the ”Plasma Crystal-3 Plus” (PK-3 Plus) laboratory. It was perfectly suited for the formation of large stable liquid and crystalline sys- tems and provided interesting insights into processes like crystallisation and melting, laning in binary mixtures, electrorheological effects due to ac electric fields and projectile interaction with a strongly coupled complex plasma cloud.
Experimental elaboration of liquid droplet cooler-radiator models under microgravity and deep vacuum conditions
The basic results of space tests of liquid droplet cooler radiator models as the main elements of frameless systems for low grade heat rejection are considered. The studies carried out have been analyzed and intermediate elaboration’s results are summarized, which concern (1) the development of generators of drop let propellant flows, (2) revealing an operational behavior of fluid collectors of various types and analysis of unsolved problems associated with droplet collection upon the open trajectory’s section passage, and (3) pro vision of the coolant circulation contour’s closing. The necessity is substantiated for the activization of works directed to carrying out space experiments with improved radiator models and new promising propellants in order to provide a possibility of creating new space power plants characterized by megawatt power levels.
INTRODUCTION: The system of countermeasures for the adverse effects of microgravity developed in the USSR supported the successful implementation of long-duration spaceflight (LDS) programs on the Salyut and Mir orbital stations and was subsequently adapted for flights on the International Space Station (ISS). From 2000 through 2010, crews completed 26 ISS flight increments ranging in duration from 140 to 216 d, with the participation of 27 Russian cosmonauts. These flights have made it possible to more precisely determine a crew-member’s level of conditioning, better assess the advantages and disadvantages of training processes, and determine prospects for future developments.
The effect of microgravity on the in vitro NK cell function during six International Space Station Missions
The level of natural killer (NK) cytotoxic activity was measured during co-cultivation of human lymphocytes and target cells (K- 562) in microgravity. Flight experiments were carried out using special instrumentation, the “Fibroblast-1” cassettes, in the frame of Russian scientific program during six ISS missions. Lymphocyte suspensions from human venous blood were used in experiments during short-term flights on six ISS missions (7 –12). Russian space crew members performed the experiments after Soyuz docking. The first step was mixing lymphocytes and 3H-labeled K-562 cells and their incubation at 37°C during 24 hs; the second step was filtration of the cell suspension. The frozen medium and filters were analyzed for the cytokine level and cytotoxic activity after landing. It was found that lympho- cytes with different basal levels of cytotoxic activity kept the ability of recognizing and lysing malignant cells. In micrograv- ity, cytotoxity increased to 160% of the basal levels. Donor indi- vidual features modulated the magnitude of the increase. The measurement of interleukin levels (TNF-α, IL-1, IL-2) in medi- um showed that synthesis of TNF-α increased during cell co-cul- tivation in microgravity. The level of IL-2 was very low in flight and ground control samples. The production of IL-1 by lympho- cytes decreased after in-flight incubation. The results indicate that microgravity did not disturb the cytotoxic function of immune cells in vitro during 24 h incubation with specific target cells.
The data from the R3DE instrument of ESA’s EXPOSE-E mission outside the ISS at the European Technological Expose Facility (EuTEF) on the ESA Columbus module shows that the docking of the Space Shuttle with the International Space Station (ISS) decreased the South-Atlantic Anomaly (SAA) maxima dose rates from about 1500 Gy h-1 down to 600-700 Gy h-1 or by factor of 2. The dose rate data at the same time from another Bulgarian built instrument (R3DR) of the EXPOSE-R mission outside the Russian “Zvezda” module showed that: 1) before the Space Shuttle docking, the SAA dose rates measured with R3DR were higher (2500 Gy h-1) than the R3DE data; 2) The relative decrease of the SAA dose rates after the shuttle docking was only by a factor of 1.25. These differences are explained by the smaller shielding of R3DR from the body of ISS and by the larger distance of it from the body of Space Shuttle. Very similar data, but with smaller dose rates were obtained with a third Bulgarian built instrument (Liulin-5) inside Russian “Pirs” module. The analysis of the ascending/descending SAA dose rate maxima of the three instruments shows that the effect can be simply explained by the additional shielding against the 30 to 150 MeV protons of the SAA, provided by the 78 tons Shuttle to the instruments and by changing of the ISS 3D mass distribution when the ISS rotates.
It is a challenge for the human body to maintain stable blood pressure while standing. The body’s failure to do so can lead to dizziness or even fainting. For decades it has been postulated that the vestibular organ can prevent a drop in pressure during a position change–supposedly mediated by reflexes to the cardiovascular system. We show–for the first time–a significant correlation between decreased functionality of the vestibular otolith system and a decrease in the mean arterial pressure when a person stands up. Until now, no experiments on Earth could selectively suppress both otolith systems; astronauts returning from space are a unique group of subjects in this regard. Their otolith systems are being temporarily disturbed and at the same time they often suffer from blood pressure instability. In our study, we observed the functioning of both the otolith and the cardiovascular system of the astronauts before and after spaceflight. Our finding indicates that an intact otolith system plays an important role in preventing blood pressure instability during orthostatic challenges. Our finding not only has important implications for human space exploration; they may also improve the treatment of unstable blood pressure here on Earth.