Recent space flight experiments have provided many new insights into the role of gravity in plant growth and development. Scientists have been taking seeds and plants into space for decades in an effort to understand how the stressful environment of space affects them. The resultant data have yielded significant advances in the development of advanced life-support systems for long-duration space flight and a better understanding of the fundamental role of gravity in directing the growth and development of plants. Experiments have improved as new spaceflight hardware and technology paved the way for progressively more insightful and rigorous plant research in space. The International Space Station (ISS) provided an opportunity for scientists to both monitor and control their experiments in real-time. Experiments on the ISS have provided valuable insights into endogenous growth responses, light-responses, and transcriptomic and proteomic changes that occur in the microgravity environment. In recent years most studies of plants in space have used Arabidopsis thaliana, but the single-celled, Ceratopteris richardii spore is also a valuable model system that has been used to understand plant gravity response. Experiments using these fern spores have revealed a dynamic and gravity-responsive trans-cell Ca2+ current that directs polarization of these spores, and a possible role of extracellular nucleotides in establishing or contributing to this current. As technology continues to improve, space flight experiments will provide many new insights into the role and effects of gravity on plant growth and development.
Research Containing: Spaceflight
This paper will explore the opportunities and challenges in developing the commercial market in LEO through the ISS program and all its facets, including operations, mission support activities, utilization, and contracting. The role of NASA-funded research in the vertical translation of basic research in space to practical application in the market or to other government service agencies will also be addressed. Other aspects, including government regulation, investment and tax incentives, and possible roles of various government agencies will also be explored. Of particular importance, the role of private industry, currently in the supply business, in the development of the demand for LEO capabilities and services beyond the federal government will be highlighted. In conclusion, this paper will address the prospects in reaching the goal of commercializing LEO starting from where we are today in human spaceflight and the International Space Station.
Characteristics of local human skeleton responses to microgravity and drug treatment for osteoporosis in clinic
Analysis of the results of long term investigations of bones in cosmonauts on board Mir orbital sta tion(OS) and International Space Station (ISS) (n = 80) was performed. Theoretically predicted (evolution ary predefined) change in mass of different skeleton bones was found to be correlated (r = 0.904) with the position relative to Earth’s gravity vector. Vector dependence of bone loss results from local specificity of expression of bone metabolism genes, which reflects mechanical prehistory of skeleton structures in the evo lution of Homo erectus. Genetic polymorphism is accountable for high individual variability of bone loss, which is attested by the dependence of bone loss rate on polymorphism of certain genetic markers of bone metabolism. The type of the orbital vehicle did not affect the individual specific stability of the bone loss ratio in different segments of the skeleton. This fact is considered as a phenotype fingerprint of local metabolism in the form of a locus specific spatial structure of distribution of non collagen proteins responsible for posi tion regulation of endosteal metabolism. Drug treatment of osteoporosis (n = 107) evidences that recovery rate depends on bone location; the most likely reason is different effectiveness of local osteotropic interven tion into areas of bustling resorption.
Intrinsic cardiovascular autonomic regulatory system of astronauts exposed long-term to microgravity in space: observational study
The fractal scaling of the long-term heart rate variability (HRV) reflects the ‘intrinsic’ autonomic regulatory system. Herein, we examine how microgravity on the ISS affected the power-law scaling β (beta) of astronauts during a long-duration (about 6 months) spaceflight. Ambulatory electrocardiographic (ECG) monitoring was performed on seven healthy astronauts (5 men, 52.0 ± 4.2 years of age) five times: before launch, 24 ± 5 (F01) and 73 ± 5 (F02) days after launch, 15 ± 5 days before return (F03), and after return to Earth. The power-law scaling β was calculated as the slope of the regression line of the power density of the MEM spectrum versus frequency plotted on a log10–log10 scale in the range of 0.0001–0.01 Hz (corresponding to periods of 2.8 h to 1.6 min). β was less negative in space (−0.949 ± 0.061) than on Earth (−1.163 ± 0.075; P o 0.025). The difference was more pronounced during the awake than during the rest/sleep span. The circadian amplitude and acrophase (phase of maximum) of β did not differ in space as compared with Earth. An effect of microgravity was detected within 1 month (F01) in space and continued throughout the spaceflight. The intrinsic autonomic regulatory system that protects life under serious environmental conditions on Earth is altered in the microgravity environment, with no change over the 6-month spaceflight. It is thus important to find a way to improve conditions in space and/or in terms of human physiology, not to compromise the intrinsic autonomic regulatory system now that;plans are being made to inhabit another planet in the near future.
The scoring quality of astronauts’ sleeps using Fuzzy C-Means (FCM) during microgravity effect in the International Space Station (ISS)
For successful health programme of Japanese astronauts during space activity in the International Space Station (ISS), we looked into the sleep quality of astronauts by using Fuzzy C-Means (FCM). At the first step, we collected observation data by following sleep schedule of astronaut Noguchi for fifteen days (26 July 2005 to 9 August 2005) during STS-114 spaceflight. The Fuzzy C-Mean (FCM) was used to design the score quality of astronauts’ sleeps. We defined three condition of sleep quality (e.g. sleepy, sleep, deep sleep) with the minimum score (zero) and maximum score (nine). Based on the preliminary result, we found that the minimum sleep score of astronaut Noguchi was from 7 to 9 August 2005 which was due to landing process and the maximum sleep score we found was later than 27 July 2005 during docking on ISS.
Bone loss associated with microgravity exposure poses a significant barrier to long-duration spaceflight. Osteoprotegerin-Fc (OPG-Fc) is a receptor activator of nuclear factor kappa-B ligand (RANKL) inhibitor that causes sustained inhibition of bone resorption after a single subcutaneous injection. We tested the ability of OPG-Fc to preserve bone mass during 12 days of spaceflight (SF). 64-day-old female C57BL/6J mice (n=12/group) were injected subcutaneously with OPG-Fc (20mg/kg) or an inert vehicle (VEH), 24h prior to launch. Ground control (GC) mice (VEH or OPG-Fc) were maintained under environmental conditions that mimicked those in the space shuttle middeck. Age-matched baseline (BL) controls were sacrificed at launch. GC/VEH, but not SF/VEH mice, gained tibia BMD and trabecular volume fraction (BV/TV) during the mission (P<0.05 vs. BL). SF/VEH mice had lower BV/TV vs. GC/VEH mice, while SF/OPG-Fc mice had greater BV/TV than SF/VEH or GC/VEH. SF reduced femur elastic and maximum strength in VEH mice, with OPG-Fc increasing elastic strength in SF mice. Serum TRAP5b was elevated in SF/VEH mice vs. GC/VEH mice. Conversely, SF/OPG-Fc mice had lower TRAP5b levels, suggesting that OPG-Fc preserved bone during spaceflight via inhibition of osteoclast-mediated bone resorption. Decreased bone formation also contributed to the observed osteopenia, based on the reduced femur periosteal bone formation rate and serum osteocalcin level. Overall, these observations suggest that the beneficial effects of OPG-Fc during SF are primarily due to dramatic and sustained suppression of bone resorption. In growing mice, this effect appears to compensate for the SF-related inhibition of bone formation, while preventing any SF-related increase in bone resorption. We have demonstrated that the young mouse is an appropriate new model for SF-induced osteopenia, and that a single pre-flight treatment with OPG-Fc can effectively prevent the deleterious effects of SF on mouse bone.
Capillary Channel Flow (CCF) EU2–02 on the International Space Station (ISS): An Experimental Investigation of Passive Bubble Separations in an Open Capillary Channel
It would be signi cantly easier to design uid systems for spacecraft if the uid phases behaved similarly to those on earth. In this research an open 15:8 wedge- sectioned channel is employed to separate bubbles from a two-phase ow in a micro- gravity environment. The bubbles appear to rise in the channel and coalesce with the free surface in much the same way as would bubbles in a terrestrial environ- ment, only the combined e ects of surface tension, wetting, and conduit geometry replace the role of buoyancy. The host liquid is drawn along the channel by a pump and noncondensible gas bubbles are injected into it near the channel vertex at the channel inlet. Control parameters include bubble volume, bubble frequency, liq- uid volumetric ow rate, and channel length. The asymmetrically con ned bubbles are driven in the cross- ow direction by capillary forces until they at least become inscribed within the section or until they come in contact with the free surface, whereupon they usually coalesce and leave the ow. The merging of bubbles en- hances, but does not guarantee, the latter. The experiments are performed aboard the International Space Station as a subset of the Capillary Channel Flow experi- ments. The ight hardware is commanded remotely and continuously from ground stations during the tests and an extensive array of experiments is conducted identi- fying numerous bubble ow regimes and regime transitions depending on the ratio and magnitude of the gas and liquid volumetric ow rates. The breadth of the pub- licly available experiments is conveyed herein primarily by narrative and by regime maps, where transitions are approximated by simple expressions immediately useful for the purposes of design and deeper analysis.
Secretory proteins produced by salivary glands are stored in granules and released into saliva. Rodent salivary glands are a reliable experimental model because they are morphologically and functionally similar to those of humans. To determine if the effects of microgravity on secretory proteins are increased on extended flights, their expression in mouse parotid glands, morphological, immuno- cytochemical, and biochemical/molecular methods were employed. Acinar cells of STS-135 (13 day) and Bion-M1 (30 day) flight animals showed an increase of autophagy and apoptosis, while duct cells contained vacuoles with endocytosed proteins. In STS-135, decreases were seen in the regulatory subunit of type II protein kinase A (RII) by Western blotting, and demilune cell and parotid protein (DCPP) and α- amylase (p<0.01) by immunogold labeling, while proline-rich proteins (PRPs, p<0.001) and parotid secretory protein (PSP, p<0.05) were increased. These results suggest microgravity effects on secretion are function-dependent. Microarray analyses showed significant changes in the expression of a number of genes, including components of the cyclic-3',5',-adenosine monophosphate (cyclic AMP) signaling pathway. Compared to habitat ground controls, mice from both flights exhibited altered expression of cyclic AMP-specific phosphodiesterases, adenylate cyclase isoforms, and several A-kinase anchoring proteins. Bion-M1 flight mice showed increases in gene expression for lysozyme and amylase, a decrease in PRPs, and RII expression was unchanged from control values. Secretory protein expression is altered by travel in space, representing a reversible adjustment to microgravity conditions. Ultimately, the goal is to develop a test kit using saliva — an easily obtained body fluid — to assess the physiologic effects of travel in space.
Evaluation of rodent spaceflight in the NASA animal enclosure module for an extended operational period (up to 35 days)
The National Aeronautics and Space Administration Animal Enclosure Module (AEM) was developed as a self-contained rodent habitat for shuttle flight missions that provides inhabitants with living space, food, water, ventilation, and lighting, and this study reports whether, after minimal hardware modification, the AEM could support an extended term up to 35 days for Sprague-Dawley rats and C57BL/6 female mice for use on the International Space Station. Success was evaluated based on comparison of AEM housed animals to that of vivarium housed and to normal biological ranges through various measures of animal health and well-being, including animal health evaluations, animal growth and body masses, organ masses, rodent food bar consumption, water consumption, and analysis of blood contents. The results of this study confirmed that the AEMs could support 12 adult female C57BL/6 mice for up to 35 days with self-contained RFB and water, and the AEMs could also support 5 adult male Sprague-Dawley rats for 35 days with external replenishment of diet and water. This study has demonstrated the capability and flexibility of the AEM to operate for up to 35 days with minor hardware modification. Therefore, with modifications, it is possible to utilize this hardware on the International Space Station or other operational platforms to extend the space life science research use;of mice and rats.
Increased postflight carotid artery stiffness and inflight insulin resistance resulting from 6-mo spaceflight in male and female astronauts
Removal of the normal head-to-foot gravity vector and chronic weightlessness during spaceflight might induce cardiovascular and metabolic adaptations related to changes in arterial pressure and reduction in physical activity. We tested hypotheses that stiffness of arteries located above the heart would be increased postflight, and that blood biomarkers inflight would be consistent with changes in vascular function. Possible sex differences in responses were explored in four male and four female astronauts who lived on the International Space Station for 6 mo. Carotid artery distensibility coefficient (P = 0.005) and beta-stiffness index (P = 0.006) reflected 17-30% increases in arterial stiffness when measured within 38 h of return to Earth compared with preflight. Spaceflight-by-sex interaction effects were found with greater changes in beta-stiffness index in women (P = 0.017), but greater changes in pulse wave transit time in men (P = 0.006). Several blood biomarkers were changed from preflight to inflight, including an increase in an index of insulin resistance (P < 0.001) with a spaceflight-by-sex term suggesting greater change in men (P = 0.034). Spaceflight-by-sex interactions for renin (P = 0.016) and aldosterone (P = 0.010) indicated greater increases in women than men. Six-month spaceflight caused increased arterial stiffness. Altered hydrostatic arterial pressure gradients as well as changes in insulin resistance and other biomarkers might have contributed to alterations in arterial properties, including sex differences between male and female astronauts.