Open Access
Open access

npj Microgravity

Springer Nature
Springer Nature
ISSN: 23738065
SCImago
Q1
WOS
Q1
Impact factor
4.4
SJR
1.017
CiteScore
7.3
Categories
Agricultural and Biological Sciences (miscellaneous)
Biochemistry, Genetics and Molecular Biology (miscellaneous)
Materials Science (miscellaneous)
Medicine (miscellaneous)
Physics and Astronomy (miscellaneous)
Space and Planetary Science
Areas
Agricultural and Biological Sciences
Biochemistry, Genetics and Molecular Biology
Earth and Planetary Sciences
Materials Science
Medicine
Physics and Astronomy
Years of issue
2015-2025
journal names
npj Microgravity
Publications
493
Citations
7 579
h-index
42
Top-3 citing journals
Top-3 organizations
German Aerospace Center
German Aerospace Center (58 publications)
Ames Research Center
Ames Research Center (26 publications)
University of Florida
University of Florida (26 publications)
Top-3 countries
USA (271 publications)
Germany (103 publications)
France (58 publications)

Most cited in 5 years

Patel Z.S., Brunstetter T.J., Tarver W.J., Whitmire A.M., Zwart S.R., Smith S.M., Huff J.L.
npj Microgravity scimago Q1 wos Q1 Open Access
2020-11-05 citations by CoLab: 218 PDF Abstract  
NASA’s plans for space exploration include a return to the Moon to stay—boots back on the lunar surface with an orbital outpost. This station will be a launch point for voyages to destinations further away in our solar system, including journeys to the red planet Mars. To ensure success of these missions, health and performance risks associated with the unique hazards of spaceflight must be adequately controlled. These hazards—space radiation, altered gravity fields, isolation and confinement, closed environments, and distance from Earth—are linked with over 30 human health risks as documented by NASA’s Human Research Program. The programmatic goal is to develop the tools and technologies to adequately mitigate, control, or accept these risks. The risks ranked as “red” have the highest priority based on both the likelihood of occurrence and the severity of their impact on human health, performance in mission, and long-term quality of life. These include: (1) space radiation health effects of cancer, cardiovascular disease, and cognitive decrements (2) Spaceflight-Associated Neuro-ocular Syndrome (3) behavioral health and performance decrements, and (4) inadequate food and nutrition. Evaluation of the hazards and risks in terms of the space exposome—the total sum of spaceflight and lifetime exposures and how they relate to genetics and determine the whole-body outcome—will provide a comprehensive picture of risk profiles for individual astronauts. In this review, we provide a primer on these “red” risks for the research community. The aim is to inform the development of studies and projects with high potential for generating both new knowledge and technologies to assist with mitigating multisystem risks to crew health during exploratory missions.
Lee A.G., Mader T.H., Gibson C.R., Tarver W., Rabiei P., Riascos R.F., Galdamez L.A., Brunstetter T.
npj Microgravity scimago Q1 wos Q1 Open Access
2020-02-07 citations by CoLab: 207 PDF Abstract  
Prolonged microgravity exposure during long-duration spaceflight (LDSF) produces unusual physiologic and pathologic neuro-ophthalmic findings in astronauts. These microgravity associated findings collectively define the “Spaceflight Associated Neuro-ocular Syndrome” (SANS). We compare and contrast prior published work on SANS by the National Aeronautics and Space Administration’s (NASA) Space Medicine Operations Division with retrospective and prospective studies from other research groups. In this manuscript, we update and review the clinical manifestations of SANS including: unilateral and bilateral optic disc edema, globe flattening, choroidal and retinal folds, hyperopic refractive error shifts, and focal areas of ischemic retina (i.e., cotton wool spots). We also discuss the knowledge gaps for in-flight and terrestrial human research including potential countermeasures for future study. We recommend that NASA and its research partners continue to study SANS in preparation for future longer duration manned space missions.
Stavnichuk M., Mikolajewicz N., Corlett T., Morris M., Komarova S.V.
npj Microgravity scimago Q1 wos Q1 Open Access
2020-05-05 citations by CoLab: 134 PDF Abstract  
Bone loss in space travelers is a major challenge for long-duration space exploration. To quantify microgravity-induced bone loss in humans, we performed a meta-analysis of studies systematically identified from searching Medline, Embase, Web of Science, BIOSIS, NASA Technical reports, and HathiTrust, with the last update in November 2019. From 25 articles selected to minimize the overlap between reported populations, we extracted post-flight bone density values for 148 individuals, and in-flight and post-flight biochemical bone marker values for 124 individuals. A percentage difference in bone density relative to pre-flight was positive in the skull, +2.2% [95% confidence interval: +1.1, +3.3]; neutral in the thorax/upper limbs, −0.7% [−1.3, −0.2]; and negative in the lumbar spine/pelvis, −6.2 [−6.7, −5.6], and lower limbs, −5.4% [−6.0, −4.9]. In the lower limb region, the rate of bone loss was −0.8% [−1.1, −0.5] per month. Bone resorption markers increased hyperbolically with a time to half-max of 11 days [9, 13] and plateaued at 113% [108, 117] above pre-flight levels. Bone formation markers remained unchanged during the first 30 days and increased thereafter at 7% [5, 10] per month. Upon landing, resorption markers decreased to pre-flight levels at an exponential rate that was faster after longer flights, while formation markers increased linearly at 84% [39, 129] per month for 3–5 months post-flight. Microgravity-induced bone changes depend on the skeletal-site position relative to the gravitational vector. Post-flight recovery depends on spaceflight duration and is limited to a short post-flight period during which bone formation exceeds resorption.
Juhl O.J., Buettmann E.G., Friedman M.A., DeNapoli R.C., Hoppock G.A., Donahue H.J.
npj Microgravity scimago Q1 wos Q1 Open Access
2021-07-23 citations by CoLab: 97 PDF Abstract  
With the reignited push for manned spaceflight and the development of companies focused on commercializing spaceflight, increased human ventures into space are inevitable. However, this venture would not be without risk. The lower gravitational force, known as microgravity, that would be experienced during spaceflight significantly disrupts many physiological systems. One of the most notably affected systems is the musculoskeletal system, where exposure to microgravity causes both bone and skeletal muscle loss, both of which have significant clinical implications. In this review, we focus on recent advancements in our understanding of how exposure to microgravity affects the musculoskeletal system. We will focus on the catabolic effects microgravity exposure has on both bone and skeletal muscle cells, as well as their respective progenitor stem cells. Additionally, we report on the mechanisms that underlie bone and muscle tissue loss resulting from exposure to microgravity and then discuss current countermeasures being evaluated. We reveal the gaps in the current knowledge and expound upon how current research is filling these gaps while also identifying new avenues of study as we continue to pursue manned spaceflight.
Akiyama T., Horie K., Hinoi E., Hiraiwa M., Kato A., Maekawa Y., Takahashi A., Furukawa S.
npj Microgravity scimago Q1 wos Q1 Open Access
2020-05-07 citations by CoLab: 85 PDF Abstract  
The impact of spaceflight on the immune system has been investigated extensively during spaceflight missions and in model experiments conducted on Earth. Data suggest that the spaceflight environment may affect the development of acquired immunity, and immune responses. Herein we summarize and discuss the influence of the spaceflight environment on acquired immunity. Bone marrow and the thymus, two major primary lymphoid organs, are evidently affected by gravitational change during spaceflight. Changes in the microenvironments of these organs impair lymphopoiesis, and thereby may indirectly impinge on acquired immunity. Acquired immune responses may also be disturbed by gravitational fluctuation, stressors, and space radiation both directly and in a stress hormone-dependent manner. These changes may affect acquired immune responses to pathogens, allergens, and tumors.
Roy-O’Reilly M., Mulavara A., Williams T.
npj Microgravity scimago Q1 wos Q1 Open Access
2021-02-16 citations by CoLab: 81 PDF Abstract  
During spaceflight, the central nervous system (CNS) is exposed to a complex array of environmental stressors. However, the effects of long-duration spaceflight on the CNS and the resulting impact to crew health and operational performance remain largely unknown. In this review, we summarize the current knowledge regarding spaceflight-associated changes to the brain as measured by magnetic resonance imaging, particularly as they relate to mission duration. Numerous studies have reported macrostructural changes to the brain after spaceflight, including alterations in brain position, tissue volumes and cerebrospinal fluid distribution and dynamics. Changes in brain tissue microstructure and connectivity were also described, involving regions related to vestibular, cerebellar, visual, motor, somatosensory and cognitive function. Several alterations were also associated with exposure to analogs of spaceflight, providing evidence that brain changes likely result from cumulative exposure to multiple independent environmental stressors. Whereas several studies noted that changes to the brain become more pronounced with increasing mission duration, it remains unclear if these changes represent compensatory phenomena or maladaptive dysregulations. Future work is needed to understand how spaceflight-associated changes to the brain affect crew health and performance, with the goal of developing comprehensive monitoring and countermeasure strategies for future long-duration space exploration.
Man J., Graham T., Squires-Donelly G., Laslett A.L.
npj Microgravity scimago Q1 wos Q1 Open Access
2022-04-05 citations by CoLab: 64 PDF Abstract  
AbstractHumans are spending an increasing amount of time in space, where exposure to conditions of microgravity causes 1–2% bone loss per month in astronauts. Through data collected from astronauts, as well as animal and cellular experiments conducted in space, it is evident that microgravity induces skeletal deconditioning in weight-bearing bones. This review identifies contentions in current literature describing the effect of microgravity on non-weight-bearing bones, different bone compartments, as well as the skeletal recovery process in human and animal spaceflight data. Experiments in space are not readily available, and experimental designs are often limited due to logistical and technical reasons. This review introduces a plethora of on-ground research that elucidate the intricate process of bone loss, utilising technology that simulates microgravity. Observations from these studies are largely congruent to data obtained from spaceflight experiments, while offering more insights behind the molecular mechanisms leading to microgravity-induced bone loss. These insights are discussed herein, as well as how that knowledge has contributed to studies of current therapeutic agents. This review also points out discrepancies in existing data, highlighting knowledge gaps in our current understanding. Further dissection of the exact mechanisms of microgravity-induced bone loss will enable the development of more effective preventative and therapeutic measures to protect against bone loss, both in space and possibly on ground.
English K.L., Downs M., Goetchius E., Buxton R., Ryder J.W., Ploutz-Snyder R., Guilliams M., Scott J.M., Ploutz-Snyder L.L.
npj Microgravity scimago Q1 wos Q1 Open Access
2020-08-18 citations by CoLab: 57 PDF Abstract  
Historically, International Space Station (ISS) exercise countermeasures have not fully protected astronauts’ musculoskeletal and cardiorespiratory fitness. Although these losses have been reduced on more recent missions, decreasing the time required to perform in-flight exercise would permit reallocation of that time to other tasks. To evaluate the effectiveness of a new training prescription, ISS crewmembers performed either the high intensity/lower volume integrated Sprint resistance (3 d wk−1) and aerobic (interval and continuous workouts, each 3 d wk−1 in alternating fashion) exercise program (n = 9: 8M/1F, 48 ± 7 y, 178 ± 5 cm, 77.7 ± 12.0 kg) or the standard ISS countermeasure consisting of daily resistance and aerobic exercise (n = 17: 14M/3F, 46 ± 6 y, 176 ± 6 cm, 80.6 ± 10.5 kg) during long-duration spaceflight. Bone mineral density (dual energy X-ray absorptiometry (DXA)), muscle strength (isokinetic dynamometry), muscle function (cone agility test), and cardiorespiratory fitness (VO2peak) were assessed pre- and postflight. Mixed-effects modeling was used to analyze dependent measures with alpha set at P < 0.05. After spaceflight, femoral neck bone mineral density (−1.7%), knee extensor peak torque (−5.8%), cone agility test time (+7.4%), and VO2peak (−6.1%) were decreased in both groups (simple main effects of time, all P < 0.05) with a few group × time interaction effects detected for which Sprint experienced either attenuated or no loss compared to control. Although physiologic outcomes were not appreciably different between the two exercise programs, to conserve time and optimally prepare crewmembers for the performance of physically demanding mission tasks, high intensity/lower volume training should be an indispensable component of spaceflight exercise countermeasure prescriptions.
Gallo C., Ridolfi L., Scarsoglio S.
npj Microgravity scimago Q1 wos Q1 Open Access
2020-10-01 citations by CoLab: 53 PDF Abstract  
Human spaceflight has been fascinating man for centuries, representing the intangible need to explore the unknown, challenge new frontiers, advance technology, and push scientific boundaries further. A key area of importance is cardiovascular deconditioning, that is, the collection of hemodynamic changes—from blood volume shift and reduction to altered cardiac function—induced by sustained presence in microgravity. A thorough grasp of the 0G adjustment point per se is important from a physiological viewpoint and fundamental for astronauts’ safety and physical capability on long spaceflights. However, hemodynamic details of cardiovascular deconditioning are incomplete, inconsistent, and poorly measured to date; thus a computational approach can be quite valuable. We present a validated 1D–0D multiscale model to study the cardiovascular response to long-term 0G spaceflight in comparison to the 1G supine reference condition. Cardiac work, oxygen consumption, and contractility indexes, as well as central mean and pulse pressures were reduced, augmenting the cardiac deconditioning scenario. Exercise tolerance of a spaceflight traveler was found to be comparable to an untrained person with a sedentary lifestyle. At the capillary–venous level significant waveform alterations were observed which can modify the regular perfusion and average nutrient supply at the cellular level. The present study suggests special attention should be paid to future long spaceflights which demand prompt physical capacity at the time of restoration of partial gravity (e.g., Moon/Mars landing). Since spaceflight deconditioning has features similar to accelerated aging understanding deconditioning mechanisms in microgravity are also relevant to the understanding of aging physiology on the Earth.
Gómez X., Sanon S., Zambrano K., Asquel S., Bassantes M., Morales J.E., Otáñez G., Pomaquero C., Villarroel S., Zurita A., Calvache C., Celi K., Contreras T., Corrales D., Naciph M.B., et. al.
npj Microgravity scimago Q1 wos Q1 Open Access
2021-09-23 citations by CoLab: 51 PDF Abstract  
Exposure to microgravity and ionizing radiation during spaceflight missions causes excessive reactive oxygen species (ROS) production that contributes to cellular stress and damage in astronauts. Average spaceflight mission time is expected to lengthen as humanity aims to visit other planets. However, longer missions or spaceflights will undoubtedly lead to an increment in microgravity, ionizing radiation and ROS production. Strategies to minimize ROS damage are necessary to maintain the health of astronauts, future space colonists, and tourists during and after spaceflight missions. An antioxidant cocktail formulated to prevent or mitigate ROS damage during space exploration could help maintain the health of space explorers. We propose key points to consider when developing an antioxidant cocktail. We discuss how ROS damages our body and organs, the genetic predisposition of astronauts to its damage, characteristics and evidence of the effectiveness of antioxidants to combat excess ROS, differences in drug metabolism when on Earth and in space that could modify antioxidant effects, and the characteristics and efficacy of common antioxidants. Based on this information we propose a workflow for assessing astronaut resistance to ROS damage, infight monitoring of ROS production, and an antioxidant cocktail. Developing an antioxidant cocktail represents a big challenge to translate current medical practices from an Earth setting to space. The key points presented in this review could promote the development of different antioxidant formulations to maintain space explorers’ health in the future.
from 3 chars
Publications found: 497
The utility of animal models to inform the next generation of human space exploration
Duporge I., Pereira T., de Obeso S.C., Ross J.G., J. Lee S., G. Hindle A.
Q1
Springer Nature
npj Microgravity 2025 citations by CoLab: 0
Open Access
Open access
PDF  |  Abstract
Abstract Animals have played a vital role in every stage of space exploration, from early sub-orbital flights to contemporary missions. New physiological and psychological challenges arise with plans to venture deeper into the solar system. Advances in chimeric and knockout animal models, along with genetic modification techniques have enhanced our ability to study the effects of microgravity in greater detail. However, increased investment in the purposeful design of habitats and payloads, as well as in AI-enhanced behavioral monitoring in orbit can better support the ethical and effective use of animals in deep space research.
Plyometric training increases thickness and volume of knee articular cartilage in mice
Chiaberge M., Thottappillil N., Liphardt A., Furlanetto A., Odell D., Wang C., Hope S., Smee S., Rehfus J., Niehoff A., Shelhamer M., Norman C., Philippon M.J., Huard J., James A.W., et. al.
Q1
Springer Nature
npj Microgravity 2025 citations by CoLab: 0
Open Access
Open access
PDF  |  Abstract
Abstract Degeneration and thinning of articular cartilage lead to osteoarthritis and may result from reduced joint loading during e.g. bed rest or as a result of microgravity during space flight. Anabolic physical exercises for cartilage are not well studied to date. We built an experimental apparatus for plyometric training with mice to test potential benefits of jumping for articular cartilage. The exercise group (JUMP) performed jump training for 9 weeks and was compared with sedentary mice (control, CON) and hindlimb-suspended (HLS) mice (to simulate reduced loading) for the same duration. Knee cartilage was assessed via 3-dimensional reconstruction of micro-CT scans and histology. We observed significant thinning and volume reduction of articular cartilage at the medial tibial-femoral point of contact in the HLS group. Clustering of chondrocytes was present in HLS. By contrast, the JUMP group showed both cartilage thickening and volume increase. We observed a similar trend on trabecular bone thickness and volume. Our results show that plyometric training can stimulate cartilage thickness and volume in mice. This suggests further investigation of this mode of exercise as a countermeasure to prevent cartilage atrophy in disuse scenarios such as long duration spaceflight, and for patients at risk of developing osteoarthritis.
Validated space radiation exposure predictions from earth to mars during Artemis-I
Slaba T.C., Rahmanian S., George S., Laramore D., Norbury J.W., Werneth C.M., Zeitlin C.
Q1
Springer Nature
npj Microgravity 2025 citations by CoLab: 0
Open Access
Open access
PDF  |  Abstract
Abstract Accurate characterization of space radiation exposure is critical to assess and communicate multiple health risks for crewmembers participating in future exploration missions. A combination of models and on-board instruments are utilized to meet this requirement. In this work, computational models are evaluated against spaceflight measurements taken within the International Space Station, the Orion spacecraft, the BioSentinel CubeSat, and on the Martian surface. All calculations and measurements cover the exact same time period defined by the Artemis-I mission, and all model calculations were performed blind—without prior knowledge of the measurements. The models are shown to accurately characterize the absorbed dose-rate in highly complex and diverse shielding configurations in locations from Earth to Mars.
Lunar and Martian gravity alter immune cell interactions with endothelia in parabolic flight
Du Y., Han B., Biere K., Abdelmalek N., Shu X., Song C., Chen G., Li N., Tuschen M., Wu H., Sun S., Choukér A., Long M., Moser D.
Q1
Springer Nature
npj Microgravity 2025 citations by CoLab: 0
Open Access
Open access
PDF  |  Abstract
Abstract Returning to the moon and traveling to Mars represent the main targets of human space exploration missions within the upcoming decades. Comparable to microgravity, partial gravity in these destinations is assumed to dysregulate immune functions, thereby threatening astronauts´ health. To investigate the impact of partial gravity on immune cell attachment to vessel endothelia, THP-1 cells and HUVEC cell layers were monitored in a flow chamber system during parabolic flight in lunar (0.16 g) or Martian (0.38 g) gravity. Focus was set on floating speed, cell adhesion, surface molecule expression and cytoskeletal reorganization under basal and TNF-induced inflammatory environment. Floating speed of THP-1 cells was increased in partial gravity, which was accompanied by a successively lower adhesion to the endothelial HUVEC cells. Expression levels of the adhesion markers Mac-1 on THP-1 cells as well as ICAM-1 on HUVECs were found elevated in lunar and Martian gravity, which was aggravated by TNF. Analysis of cytoskeletal organization in HUVECs revealed reduced intracellular F-actin microfilament networks and a stronger cell directionality with stress fiber alignment at cell borders in partial gravity, which was intensified by TNF. In summary, altered immune cell - endothelium interactions as quantified in partial gravity conditions show similarities to cellular behavior in microgravity. However, the different magnitudes of effects in dependence of gravitational level still need to be assessed in further investigations.
Simulated deep space exposure on seeds utilizing the MISSE flight facility
Richards J.T., Mortenson T.E., Spern C.J., Mousseau T.A., Gooden J.L., Spencer L.E., Khodadad C.L., Fischer J.A., Meyers A.D., Papenfuhs C.K., Buell J.G., Levine H.G., Dimapilis D.I., Zhang Y.
Q1
Springer Nature
npj Microgravity 2025 citations by CoLab: 0
Open Access
Open access
PDF  |  Abstract
Abstract The MISSE-Seed project was designed to investigate the effects of space exposure on seed quality and storage. The project tested the Multipurpose Materials International Space Station Experiment—Flight Facility (MISSE-FF) hardware as a platform for exposing biological samples to the space environment outside the International Space Station (ISS). Furthermore, it evaluated the capability of a newly designed passive sample containment canister as a suitable exposure unit for biological samples for preserving their vigor while exposing to the space environment to study multi-stressor effects. The experiment was launched to the ISS on Northrup Grumman (NG)-15. The exposure lasted eight months outside the ISS in the MISSE-FF at the Zenith position. The specimens consisted of eleven seed varieties. Temperature dataloggers and thermoluminescent dosimeters were included in each container to record environmental data. We presented here the hardware and experimental design, environmental profiles, and seed survival from post-flight germination tests.
Hypergravity is more challenging than microgravity for the human sensorimotor system
Chomienne L., Sainton P., Sarlegna F.R., Bringoux L.
Q1
Springer Nature
npj Microgravity 2025 citations by CoLab: 0
Open Access
Open access
PDF  |  Abstract
The importance of gravity for human motor control is well established, but it remains unclear how the central nervous system accounts for gravitational changes to perform complex motor skills. We tested the hypothesis that microgravity and hypergravity have distinct effects on the neuromuscular control of reaching movements compared to normogravity. To test the influence of gravity levels on sensorimotor planning and control, participants (n = 9) had to reach toward visual targets during parabolic flights. Whole-body kinematics and muscular activity were adjusted in microgravity, allowing arm reaching to be as accurate as in normogravity. However, we observed in hypergravity a systematic undershooting, which likely resulted from a lack of reorganization of muscle activations. While new studies are necessary to clarify whether hypergravity impairs the internal model of limb dynamics, our findings provide new evidence that hypergravity creates a challenge that the human sensorimotor system is unable to solve in the short term.
Space exploration and risk of Parkinson’s disease: a perspective review
Ali N., Beheshti A., Hampikian G.
Q1
Springer Nature
npj Microgravity 2025 citations by CoLab: 0
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Open access
PDF  |  Abstract
Systemic mitochondrial dysfunction, dopamine loss, sustained structural changes in the basal ganglia including reduced tyrosine hydroxylase, and altered gait- these effects observed in space-flown animals and astronauts mirrors Parkinson’s disease (PD). Evidence of mitochondrial changes in space-flown human cells, examined through the lens of PD, suggests that spaceflight-induced PD-like molecular changes are important to monitor during deep space exploration. These changes, may potentially elevate the risk of PD in astronauts.
Aerospace medicine in China: advancements and perspectives
Wang A., Yang J., Tang S., Cui Y., Zhao J., Wang J., Li X., Zhao Y., Wang G., Du J.
Q1
Springer Nature
npj Microgravity 2024 citations by CoLab: 0
Open Access
Open access
PDF  |  Abstract
With the rapid growth of China’s space industry, long-term manned space missions face challenges from the complex space environment, posing risks to human health. Aerospace medicine, a key field, addresses these risks by researching the impacts of space on biochemical changes, cognitive abilities, and immune systems. This article reviews China’s aerospace medicine research, summarizing efforts from various institutions and offering insights for future developments in the field.
Hypothesis on the outflow of optic nerve cerebrospinal fluid in spaceflight associated neuro ocular syndrome
Hu Y., Lin Y., Cheng L., Xu Y., Zhang J., Zheng Z., Wang H., Yan M., Chen H.
Q1
Springer Nature
npj Microgravity 2024 citations by CoLab: 0
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Open access
PDF  |  Abstract
Spaceflight-associated neuro-ocular syndrome (SANS) has been well documented in astronauts. However, its pathogenesis is not fully understood. New findings indicate the impaired outflow of the optic nerve cerebrospinal fluid may participate or contribute to some changes in SANS. In this perspective, we generated a hypothesis that the outflow of cerebrospinal fluid through the optic nerve sheath may be impaired under micro-gravity and then may potentially lead to SANS-related alterations.
An advanced light scattering apparatus for investigating soft matter onboard the International Space Station
Martinelli A., Buzzaccaro S., Galand Q., Behra J., Segers N., Leussink E., Dhillon Y.S., Maes D., Lutsko J., Piazza R., Cipelletti L.
Q1
Springer Nature
npj Microgravity 2024 citations by CoLab: 0
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Open access
PDF  |  Abstract
Colloidal solids (COLIS) is a state-of-the-art light scattering setup developed for experiments onboard the International Space Station (ISS). COLIS allows for probing the structure and dynamics of soft matter systems on a wide range of length scales, from a few nm to tens of microns, and on time scales from 100 ns to tens of hours. In addition to conventional static and dynamic light scattering, COLIS includes depolarized dynamic light scattering, a small-angle camera, photon correlation imaging, and optical manipulation of thermosensitive samples through an auxiliary near-infrared laser beam, thereby providing a unique platform for probing soft matter systems. We demonstrate COLIS through ground tests on standard Brownian suspensions, and on protein, colloidal glasses, and gel systems similar to those to be used in future ISS experiments.
Comparative study of gravity effects in directional solidification of Al-3.5 wt.% Si and Al-10 wt.% Cu alloys
Zhang G., Luo X., Li Y., Liu S.
Q1
Springer Nature
npj Microgravity 2024 citations by CoLab: 0
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PDF  |  Abstract
Directional solidification experiments of Al-3.5 wt.% Si and Al-10 wt.% Cu alloys were conducted under gravity and microgravity conditions using a 50-m-high drop tube. The solidification morphology of the two alloys is mainly columnar dendrites and equiaxed dendrites, respectively. The dendrite arm spacing (DAS), eutectic content, grain size, and compositional distribution of both alloys exhibit distinct characteristics under gravity and microgravity conditions. The study introduces an innovative perspective by taking solute density and its redistribution behavior into account when discussing the gravity effects during the directional solidification of alloys. The results indicate that the way gravity works on the solidification behavior of alloys depends strongly on the redistribution behavior and density of solute as well as crystallization modes, such as columnar grain or equiaxed grain. These findings are helpful in clarifying the coupling mechanism of gravity and relevant factors on the solidification of alloys, not only contributing to understanding the effect of gravity on solidification better but also offering valuable guidance for eliminating solidification segregation and producing high-performance alloys.
Sex-specific cardiovascular adaptations to simulated microgravity in Sprague-Dawley rats
Elsangeedy E., Yamaleyeva D.N., Edenhoffer N.P., Deak A., Soloshenko A., Ray J., Sun X., Shaltout O.H., Cruz-Diaz N., Westwood B., Kim-Shapiro D., Diz D.I., Soker S., Pulgar V.M., Ronca A., et. al.
Q1
Springer Nature
npj Microgravity 2024 citations by CoLab: 0
Open Access
Open access
PDF  |  Abstract
Men and women have different cardiovascular responses to spaceflight; however, few studies have focused on direct comparisons between sexes. We investigated the mechanisms of aortic stiffening in socially and sexually mature 20-week-old male and female Sprague Dawley (SD) rats exposed to hindlimb unloading (HLU) for 14 days. Pulse wave velocity (PWV) was greater in the aortic arch of females after HLU versus control females (n = 6–8). HLU had no effect on aortic PWV in males (n = 5–6). Aortic α smooth muscle actin, myosin, collagen, elastin, and collagen-to-elastin ratio were not different in rats of either sex following HLU. The levels of G protein-coupled estrogen receptor (GPER) were lower in the aorta of SD females exposed to HLU compared with female controls but were not altered in males. HLU females also had lower aortic PPARγ, increased oxidative stress markers, and diastolic dysfunction compared with control females. GPER agonist G1 prevented the increase in PWV and 8-hydroxy-2’-deoxyguanosine without altering PPARγ or p47phox in HLU females (n = 4 in each group) suggesting that lower GPER may contribute to arterial stiffening in the setting of simulated microgravity. This study highlights sex-specific vascular adaptations to the state of simulated microgravity.
Impact of near continuous low dose rate neutron irradiation on pregnancy outcomes in mice
Steller J.G., Blue R.S., Ronca A.E., Goodspeed A., Powell T.L., Jansson T.
Q1
Springer Nature
npj Microgravity 2024 citations by CoLab: 0
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Open access
PDF  |  Abstract
The effects of galactic cosmic radiation on reproductive physiology remain largely unknown. We determined the impact of near-continuous low-dose-rate Californium-252 neutron irradiation (1 mGy/day) as a space-relevant analog on litter size and number of resorptions at embryonic day (E) 12.5 (n = 19 radiated dams, n = 20 controls) and litter size, number of resorptions, fetal growth, and placental signaling and transcriptome (RNA sequencing) at E18.5 (n = 21 radiated dams, n = 20 controls) in pregnant mice. A significantly increased early resorption rate and decreased placental weight were observed in irradiated mice. There were no statistically significant differences in litter size, fetal weight, length, or malformation rate between the groups. Near-continuous radiation had no significant effects on the mechanistic target of rapamycin (mTOR), endoplasmic reticulum stress or inflammatory signaling, rate of double-stranded DNA breaks, and had minimal effects on gene expression in the placenta. These data suggest that near-continuous, low-level galactic cosmic radiation has a limited impact on pregnancy outcomes.
Simulating microgravity with 60 days of 6 degree head-down tilt bed rest compromises sleep
Strauch L., von der Wiesche M., Noppe A., Mulder E., Rieger I., Aeschbach D., Elmenhorst E.
Q1
Springer Nature
npj Microgravity 2024 citations by CoLab: 0
Open Access
Open access
PDF  |  Abstract
AbstractAstronauts in space often experience sleep loss. In the AGBRESA (Artificial Gravity Bed Rest) study, we examined 24 participants (mean age ± SD, 33 ± 9 years) during two months of 6o head-down tilt (HDT) bed rest, which is a well-established spaceflight analogue. Polysomnography was recorded during baseline (BDC-9), HDT (nights 1, 8, 30 and 58) and recovery (R, nights 1 and 12). Mixed ANOVAs with post-hoc step-down Bonferroni adjustment indicated that compared to BDC-9, arousals were increased, while sleep duration, N3, and sleep efficiency were all decreased during HDT. Significant quadratic associations between sleep duration and quality with time into HDT did not indicate adaptive improvements during the course of HDT. While sleep duration recovered quickly after the end of bed rest, participants still displayed protracted sleep fragmentation. We conclude that physiological changes caused by exposure to microgravity may contribute to persistent sleep deficits experienced during real space missions.
Stressors affect human motor timing during spaceflight
Tian Y., Zhang Z., Jiang C., Chen D., Liu Z., Wei M., Wang C., Wei K.
Q1
Springer Nature
npj Microgravity 2024 citations by CoLab: 0
Open Access
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PDF  |  Abstract
Crewed outer-space missions require adequate motor capacity among astronauts, whose sensorimotor system is disturbed by microgravity. Stressors other than microgravity, e.g., sleep loss, confinement, and high workload, characterize the living experience in space and potentially affect motor performance. However, the evidence of these stressors remains elusive. We recruited twelve taikonauts from the China Space Station to conduct a motor timing task that minimized the effect of microgravity on motor performance. Participants showed a remarkable increase in motor timing variance during spaceflight, compared to their pre- and post-flight performance and that of ground controls. Model-based analysis revealed that their timing deficits were driven by increased central noise instead of impaired motor execution. Our study provides evidence that nonspecific stressors can profoundly affect motor performance during spaceflight.

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