rss_2.0Gravitational and Space Research FeedSciendo RSS Feed for Gravitational and Space Research and Space Research 's Cover the Approach to Understand a Trash-to-Gas Experiment in a Microgravity Environment<abstract> <title style='display:none'>Abstract</title> <p>The Orbital Syngas/Commodity Augmentation Reactor (OSCAR) project investigated hardware and engineering development for waste conversion operations related to trash deconstruction and repurposing for long duration space missions. Operations of the trash-to-gas system were investigated to compare microgravity (μg) and Earth gravity environments. The OSCAR system has been demonstrated in other μg platforms, but here the performance and results on the Blue Origin New Shepard Suborbital Vehicle are discussed. The OSCAR suborbital operation demonstrated the introduction of trash into a high temperature reactor for solid to gas conversion, ignition of mixed trash feedstock, combustion during μg, and subsequent gas collection processes in a flight automated sequence. An oxygen (O<sub>2</sub>)- and steam-rich environment was created within the reactor for ignition conditions, and the product gases were quantified to verify the reaction product composition. This paper focuses on the chemistry processes of the reactor, and gas and solid product analysis of the μg and gravity conditions. The gas production, reactor thermal profile, and mass and carbon conversion results validated confidence in the system design to continue the advancement of this technology for future spaceflight implementations.</p> </abstract>ARTICLE2021-05-24T00:00:00.000+00:00Shared Metabolic Remodeling Processes Characterize the Transcriptome of within Various Suborbital Flight Environments<abstract> <title style='display:none'>Abstract</title> <p>The increasing availability of flights on suborbital rockets creates new avenues for the study of spaceflight effects on biological systems, particularly of the transitions between hypergravity and microgravity. This paper presents an initial comparison of the responses of Arabidopsis thaliana to suborbital and atmospheric parabolic flights as an important step toward characterizing these emerging suborbital platforms and their effects on biology. Transcriptomic profiling of the response of the Arabidopsis ecotype Wassilewskija (WS) to the aggregate suborbital spaceflight experiences in Blue Origin New Shepard and Virgin Galactic SpaceShipTwo revealed that the transcriptomic load induced by flight differed between the two flights, yet was biologically related to traditional parabolic flight responses. The sku5 skewing mutant and 14-3-3κ:GFP regulatory protein overexpression lines, flown in the Blue Origin and parabolic flights, respectively, each showed altered intra-platform responses compared to WS. An additional parabolic flight using the F-104 Starfighter showed that the response of 14-3-3κ:GFP to flight was modulated in a similar manner to the WS line. Despite the differing genotypes, experimental workflows, flight profiles, and platforms, differential gene expression linked to remodeling of central metabolic processes was commonly observed in the flight responses. However, the timing and directionality of differentially expressed genes involved in the conserved processes differed among the platforms. The processes included carbon and nitrogen metabolism, branched-chain amino acid degradation, and hypoxic responses. The data presented herein highlight the potential for various suborbital platforms to contribute insights into biological responses to spaceflight, and further suggest that in-flight fixation during suborbital experiments will enhance insights into responses during each phase of flight.</p> </abstract>ARTICLE2021-01-29T00:00:00.000+00:00Research Flights on Blue Origin's New Shepard<abstract> <title style='display:none'>Abstract</title> <p>Blue Origin's New Shepard launch vehicle made its first flight above the Kármán Line, returning safely to Earth in November 2015. At the time when this paper is being written (February 2021), the system has conducted 14 flights, including 10 with research and education payloads aboard. More than 100 payloads have exercised a wide range of capabilities and interfaces, from small cubesat-form factor student payloads to large custom payloads of nearly 100 kg. Investigations have spanned a wide range of high-altitude and microgravity research objectives, as well as raising technology readiness level (TRL) on diverse hardware. This paper summarizes New Shepard's payload missions to date, and presents standardized and custom accommodations, both in the shirtsleeve cabin and directly exposed to the space environment.</p> </abstract>ARTICLE2021-03-20T00:00:00.000+00:00APL JANUS System Progress on Commercial Suborbital Launch Vehicles: Moving the Laboratory Environment to Near Space<abstract> <title style='display:none'>Abstract</title> <p>Multiple private companies are building suborbital reusable launch vehicles possessing vastly different designs. Many of these companies originally focused on space tourism; however, revolutionary applications for scientific and engineering research as well as technology demonstrations and instrument development are emerging. The dramatic reduction in cost over traditional launch systems as well as a guaranteed (and rapid) safe payload return enable many new launch vehicle applications. These new capabilities will essentially move the laboratory environment up to the edge of space. To make use of these novel launch vehicles, the John Hopkins University Applied Physics Laboratory has established a Commercial Suborbital Program with a core system (JANUS) to support and enable many future suborbital missions. This program has already conducted six suborbital flight missions to establish vehicle interfaces and analyze the suitability and limits of each flight environment. Additionally, this program has also been selected by the NASA Flight Opportunities Program for five additional operational suborbital missions. Here we present the results of our completed missions as well as descriptions of future selected missions scheduled for 2021–2023.</p> </abstract>ARTICLE2021-01-29T00:00:00.000+00:00The Adhesive Response of Regolith to Low-Energy Disturbances in Microgravity<abstract> <title style='display:none'>Abstract</title> <p>Small, airless bodies are covered by a layer of regolith composed of particles ranging from μm-size dust to cm-size pebbles that evolve under conditions very different than those on Earth. Flight-based microgravity experiments investigating low-velocity collisions of cm-size projectiles into regolith have revealed that certain impact events result in a mass transfer from the target regolith onto the surface of the projectile. The key parameters that produce these events need to be characterized to understand the mechanical behavior of granular media, which is composed of the surfaces of small bodies. We carried out flight and ground-based research campaigns designed to investigate these mass transfer events. The goals of our experimental campaigns were (1) to identify projectile energy thresholds that influence mass transfer outcomes in low-energy collision events between cm-size projectiles and μm-size regolith, (2) to determine whether these mass transfer events required a microgravity environment to be observed, and (3) to determine whether the rebound portion of these collision events could be replicated in a laboratory drop tower environment. We found that (1) mass transfer events occurred for projectile rebound accelerations &lt;7.8 m/s<sup>2</sup> and we were unable to identify a corresponding impact velocity threshold, (2) mass transfer events require a microgravity environment, and (3) ourdrop tower experiments were able to produce mass transfer events. However, drop tower experiments do not exactly reproduce the free-particle impacts and rebound of the long-duration microgravity experiments and yielded systematically lower amounts of the overall mass transferred.</p> </abstract>ARTICLE2021-01-29T00:00:00.000+00:00Liquid Propellant Mass Measurement in Microgravity<abstract> <title style='display:none'>Abstract</title> <p>The Modal Propellant Gauging (MPG) experiment has demonstrated sub-1% gauging accuracy under laboratory conditions on both flight hardware and subscale tanks. Recently, MPG was adapted for flight on Blue Origin's New Shepard vehicle and has flown twice, achieving equilibrated, zero-g surface configurations of propellant simulant at three different fill fractions. Flight data from MPG missions on New Shepard P7 and P9 show agreement between known and measured propellant levels of 0.3% for the fill fractions investigated in the present study. Two approaches for estimating zero-g propellant mass are described here. Both approaches rely on measuring shifts in modal frequencies of a tank excited by acoustic surface waves and subject to fluid mass loading by the propellant. In the first approach, shifts in the lowest mode frequency (LMF) are measured and associated with liquid fill-level changes. In the second approach, 1-g modal spectra at a range of known fill levels are used in a cross-correlation calculation to predict fill levels associated with a zero-g modal spectrum. Flight data for both approaches are consistent with finite element predictions using a simple fluid–structure interaction model. In both settled and unsettled microgravity environments, MPG meets or exceeds NASA Roadmap goals for in-space propellant mass gauging.</p> </abstract>ARTICLE2021-02-26T00:00:00.000+00:00A Rapid Fabrication Methodology for Payload Modules, Piloted for the Observation of Queen Honey Bees () in Microgravity<abstract> <title style='display:none'>Abstract</title> <p>Microgravity experiment modules for living organisms have been instrumental to space research, yet their design remains complex and costly. As the private space sector enables more widely available payloads for researchers, it is increasingly necessary to design experimental modules innovatively so that they are proportionately accessible. To ease this bottleneck, we developed a rapid fabrication methodology for producing custom modules compatible with commercial payload slots. Our method creates a unified housing geometry, based on a given component layout, which is fabricated in a digital design and subtractive manufacturing process from a single lightweight foam material. This module design demonstrated a 25–50% reduction in chassis weight compared with existing models, and is extremely competitive in manufacturing time, simplicity, and cost. To demonstrate the ability to capture data on previously limited areas of space biology, we apply this methodology to create an autonomous, video-enabled module for sensing and observing queen and retinue bees aboard the Blue Origin New Shepard 11 (NS-11) suborbital flight. To explore whether spaceflight impacts queen fitness, results used high-definition visual data enabled by the module's compact build to analyze queen-worker regulation under microgravity stress (n = 2, with controls). Overall, this generalizable method for constructing experimental modules provides wider accessibility to space research and new data on honey bee behavior in microgravity.</p> </abstract>ARTICLE2021-06-01T00:00:00.000+00:00Aspect Ratio Dependence of Isotropic-Nematic Phase Separation of Nanoplates in Gravity<abstract><title style='display:none'>Abstract</title><p>We studied isotropic-nematic (I-N) phase separation via gravity sedimentation in suspensions of plate-like colloidal particles of identical thickness but different lateral sizes (diameters). It is well-known that I-N phase transition occurs at a higher concentration for particles with larger aspect ratio (thickness/diameter) than for particles with smaller aspect ratio. Here we report that for the larger aspect ratios of nanoplates, gravity-driven I-N phase separation is faster. In a homogenously mixed I-N biphasic suspension of nanoplates, nematic tactoids nucleate, grow, and then undergo sedimentation in gravity, leading to the formation of a clear horizontal interface between the I and N phase. For I-N coexistent suspension of nanoplates with different aspect ratios but the same amount of nematic fractions, the larger the aspect ratio, the faster the formation of nematic tactoids and interface between isotropic liquid and nematic liquid crystal phase. The tactoid formation rate is governed by the rotational and translational diffusion rates, which are faster at larger aspect ratios. The time required for I-N separation (t*, seconds) varies inversely with the mean aspect ratio (&lt; <italic>ξ</italic> &gt;) of nanoplates and follows the relation, <italic>t</italic><sup>*</sup> = <italic>α</italic> &lt; <italic>ξ</italic> &gt;<sup><italic>n</italic></sup>, where <italic>α</italic> = 0.97 ± 1.30 s and <italic>n</italic> = −2.1 ± 0.2. The phase separation kinetics studied in our experiments offers guidance for the selection of aspect ratio of nanoplates for samples to be studied at the International Space Station (ISS).</p></abstract>ARTICLE2020-07-17T00:00:00.000+00:00Establishing a Low Redox Potential in Giant Yeast Colonies: Effects of Media and Rotation<abstract><title style='display:none'>Abstract</title><p>Giant yeast colonies develop a low redox potential, which mimics the electrophilic milieu of both the mitochondrial drug metabolizing compartment and the hypoxic core of many tumors. The major metabolic mediators of low redox potential include: ATP, glutathione, NAD+/NADH, and NADP+/NADPH. Ammonia signaling is the critical mechanism that induces stratification of the giant yeast colonies to allow a low redox potential. A comparison of two powerful investigative models for drug pathways using <italic>Saccharomyces cerevisiae</italic> have been compounded by the use of different growth media and stimuli to the system. Chemogenetic profiling, which uses a pool of yeast deletion mutants to determine survival changes, is heavily slanted to the use of rich media. Giant yeast colonies studies are heavily slanted to the use of poor media. The current study answers the question “what is the difference over time in redox potential, and its major metabolic mediators, between giant yeast colonies grown on rich and poor media?” Using gene deletion tools, we show that cell death in giant yeast colonies is ammonia-dependent. In poor nutrient, ammonia-depleted (Sok2 deletion mutants) giant yeast cultures, rotation can allow manipulation of reactive oxygen species, providing a model to compare high and low redox states without chemical administration. Mechanistically, these changes are not due to detectable NAD/NAPH or NADP/NADPH changes, but are related in changes in glutathione and ATP concentration.</p></abstract>ARTICLE2020-07-17T00:00:00.000+00:00Altered Functions of Human Blood-Derived Vascular Endothelial Cells by Simulated Microgravity<abstract><title style='display:none'>Abstract</title><p>Recently, the increase in incidence of cardiovascular degeneration associated with weightlessness has drawn much attention to the detrimental effects of space travel on cardiovascular health. Particularly, the regulatory role of the endothelium in cardiovascular degeneration has been studied extensively. The goal of this study was to understand the effects of simulated microgravity on the proliferative, secretory, and anti-thrombogenic functions of endothelial cells differentiated from human blood-derived progenitor cells. Exposure to simulated microgravity enhanced proliferation, as well as the release of soluble nitric oxide while downregulating the release of pro-inflammatory cytokines, such as interleukin-6 (IL-6). Interestingly, the cells also upregulated gene expression of heat shock protein 70 (hsp70), which may be a potential adaptation mechanism of the cells to altered gravity conditions. However, the secretory and proliferative functions had no effect on the anti-thrombogenic functions of these cells. Their anti-coagulative and anti-thrombogenic abilities, as assessed by both upregulation of tissue plasminogen activator (tPA) and their ability to delay plasma clotting, were impaired on exposure to simulated microgravity. These results collectively provide a useful insight into various mechanisms involved in regulating anti-thrombogenic ability of the endothelium, as well as cardiovascular health in altered gravity conditions.</p></abstract>ARTICLE2020-07-17T00:00:00.000+00:00Physiological Effects of Spaceflight/Unloading and the Mitigating Effects of Flywheel-Based Resistive Exercise<abstract><title style='display:none'>Abstract</title><p>The deleterious effects of spaceflight encompass numerous physiological effects that undermine long-term goals of manned round-trip missions to Mars. Among the greater losses are to the human musculoskeletal system due to limited mechanical/load-bearing activity. In-flight exercise and nutritional countermeasures seek to reduce physiological losses. Restoration of mechanical/load-bearing activity in microgravity is achieved with flywheel-based exercise hardware. Research with spaceflight analogs showed exercise done with flywheel-based devices abated muscle mass and strength losses with modest increases in net energy costs. This led to the installment of flywheel-based hardware on The International Space Station (ISS). To date, exercise with flywheel-based hardware has reduced musculoskeletal losses, with more success achieved for muscle-, versus bone-based, outcomes. In-flight exercise may better address bone losses with hardware that imparts high rates of impulse loading to the engaged musculoskeleton.</p></abstract>ARTICLE2020-07-17T00:00:00.000+00:00Effects of Microgravity and Clinorotation on the Virulence of , , , and<abstract><title style='display:none'>Abstract</title><p>To evaluate effects of microgravity on virulence, we studied the ability of four common clinical pathogens—<italic>Klebsiella</italic>, <italic>Streptococcus</italic>, <italic>Proteus</italic>, and <italic>Pseudomonas</italic>—to kill wild type <italic>Caenorhabditis elegans</italic> (<italic>C. elegans)</italic> nematodes at the larval and adult stages. Simultaneous studies were performed utilizing spaceflight, rotation in a 2D clinorotation device, and static ground controls. Nematodes, microbes, and growth media were separated until exposed to true or modeled microgravity, then mixed and grown for 48 hours. Experiments were terminated by paraformaldehyde fixation, and optical density measurements were used to assay residual microorganisms. Spaceflight was associated with reduced virulence for <italic>Klebsiella</italic> and <italic>Streptococcus</italic>, but had negligible effect on <italic>Enterococcus</italic> and <italic>Pseudomonas.</italic> Clinorotation generated very different results with all four organisms showing significantly reduced virulence. We conclude that clinorotation is not a consistent model of the changes that actually occur under microgravity conditions. Further, bacteria virulence is unchanged or reduced, not increased during spaceflight.</p></abstract>ARTICLE2020-07-17T00:00:00.000+00:00Comparative Responses to Squats Completed with Free Weights and an Exoskeleton<abstract><title style='display:none'>Abstract</title><p>To assess the comparative similarity of squat data collected as they wore a robotic exoskeleton, female athletes (n=14) did two exercise bouts spaced 14 days apart. Data from their exoskeleton workout was compared to a session they did with free weights. Each squat workout entailed a four-set, four-repetition paradigm with 60-second rest periods. Sets for each workout involved progressively heavier (22.5, 34, 45.5, 57 kg) loads. The same physiological, perceptual, and exercise performance dependent variables were measured and collected from both workouts. Per dependent variable, Pearson correlation coefficients, t-tests, and Cohen's d effect size compared the degree of similarity between values obtained from the exoskeleton and free weight workouts. Results show peak O<sub>2</sub>, heart rate, and peak force data produced the least variability. In contrast, far more inter-workout variability was noted for peak velocity, peak power, and electromyography (EMG) values. Overall, an insufficient amount of comparative similarity exists for data collected from both workouts. Due to the limited data similarity, the exoskeleton does not exhibit an acceptable degree of validity. Likely the cause for the limited similarity was due to the brief amount of familiarization subjects had to the exoskeleton prior to actual data collection. A familiarization session that accustomed subjects to squats done with the exoskeleton prior to actual data collection may have considerably improved the validity of data obtained from that device.</p></abstract>ARTICLE2020-07-17T00:00:00.000+00:00Ballooning for Biologists: Mission Essentials for Flying Life Science Experiments to Near Space on NASA Large Scientific Balloons<p>Despite centuries of scientific balloon flights, only a handful of experiments have produced biologically relevant results. Yet unlike orbital spaceflight, it is much faster and cheaper to conduct biology research with balloons, sending specimens to the near space environment of Earth's stratosphere. Samples can be loaded the morning of a launch and sometimes returned to the laboratory within one day after flying. The National Aeronautics and Space Administration (NASA) flies large unmanned scientific balloons from all over the globe, with missions ranging from hours to weeks in duration. A payload in the middle portion of the stratosphere (~35 km above sea level) will be exposed to an environment similar to the surface of Mars—temperatures generally around −36°C, atmospheric pressure at a thin 1 kPa, relative humidity levels &lt;1%, and harsh illumination of ultraviolet (UV) and cosmic radiation levels (about 100 W/m<sup>2</sup> and 0.1 mGy/d, respectively)—that can be obtained nowhere else on the surface of the Earth, including environmental chambers and particle accelerator facilities attempting to simulate space radiation effects. Considering the operational advantages of ballooning and the fidelity of space-like stressors in the stratosphere, researchers in aerobiology, astrobiology, and space biology can benefit from balloon flight experiments as an intermediary step on the extraterrestrial continuum (i.e., ground, low Earth orbit, and deep space studies). Our review targets biologists with no background or experience in scientific ballooning. We will provide an overview of large balloon operations, biology topics that can be uniquely addressed in the stratosphere, and a roadmap for developing payloads to fly with NASA.</p>ARTICLE2020-07-20T00:00:00.000+00:00Injecting a Liquid in Weightlessness: Droplet or Geyser Formation<p>Injecting a liquid into a gas-filled vessel while in weightlessness can result in at least two conditions–a droplet attached to the wall around the injection orifice and a geyser in which the liquid propagates away from the orifice in a continuous jet. The need to design injection of liquid to accomplish one condition or the other shows up in both zero-<italic>g</italic> fluids research geometries and spaceflight systems. Previous experiments by others assumed the rim of the injection orifice to be sharp. Liquid flow out of orifices with chamfered and rounded rims during the weightlessness of parabolic aircraft flight are studied in this work. When compared to previous work, results indicate that chamfered and rounded rims have little effect on the value of Weber number dividing the wall-bound droplet and geyser behaviors. Because any manufactured orifice will have finite bluntness, this conclusion is useful for both research and spaceflight systems.</p>ARTICLE2020-07-20T00:00:00.000+00:00Validation of Methods to Assess the Immunoglobulin Gene Repertoire in Tissues Obtained from Mice on the International Space Station<p>Spaceflight is known to affect immune cell populations. In particular, splenic B-cell numbers decrease during spaceflight and in ground-based physiological models. Although antibody isotype changes have been assessed during and after spaceflight, an extensive characterization of the impact of spaceflight on antibody composition has not been conducted in mice. Next Generation Sequencing and bioinformatic tools are now available to assess antibody repertoires. We can now identify immunoglobulin gene-segment usage, junctional regions, and modifications that contribute to specificity and diversity. Due to limitations on the International Space Station, alternate sample collection and storage methods must be employed. Our group compared Illumina MiSeq<sup>®</sup> sequencing data from multiple sample preparation methods in normal C57Bl/6J mice to validate that sample preparation and storage would not bias the outcome of antibody repertoire characterization. In this report, we also compared sequencing techniques and a bioinformatic workflow on the data output when we assessed the IgH and Igκ variable gene usage. Our bioinformatic workflow has been optimized for Illumina HiSeq<sup>®</sup> and MiSeq<sup>®</sup> datasets, and is designed specifically to reduce bias, capture the most information from Ig sequences, and produce a data set that provides other data mining options.</p>ARTICLE2020-07-20T00:00:00.000+00:00Plant Pillow Preparation for the Veggie Plant Growth System on the International Space Station<p>The first Veggie plant growth chamber was installed on the International Space Station in 2014. Crop plants can be grown in Veggie using plant pillows, small rooting packets that contain substrate, fertilizer, and germination wicks along with attached seeds. The pillows were designed to interface with the Veggie root mat reservoir watering system to provide a capillary water column to growing plants. In preparation for flight, methods of arcillite substrate washing, autoclaving, and drying were established to reduce dust and to provide a dry sterile substrate. A controlled released fertilizer mixed into arcillite substrate provides nutrition for plant growth. Methods of seed surface sterilization were tested for both germination and microbial contamination, and the optimum methods were determined for candidate flight crops. Plant pillows were prepared for flight by cutting and inserting germination wicks, filling with the substrate/fertilizer mix, and sewing closed. Following pillow filling, seeds were attached to the wicks, and the pillows were packaged for flight. Pillow preparation methods have been successfully tested in the VEG-01 hardware validation tests on the International Space Station with ‘Outredgeous’ lettuce and ‘Profusion’ zinnia, and in the VEG-03 test, using ‘Outredgeous’ lettuce and ‘Tokyo bekana’ Chinese cabbage.</p>ARTICLE2020-07-20T00:00:00.000+00:00Lower Leg Anatomical Correlates to Performance and Metabolism from Flywheel-based Exercise<p>Lower leg exercises are impacted by the anatomy of the triceps surae-Achilles tendon complex. Such exercises may utilize series elastic energy (SEE), temporarily stored within the Achilles tendon, to augment forces exerted by the triceps surae. While SEE's contribution to bipedal jumping and walking have been assessed, other lower leg exercises yet to receive similar scrutiny include seated calf presses done on flywheel-based hardware. Current subjects did two identical calf press workouts on a flywheel ergometer. The following three variables were obtained from workouts–the total work (TW) performed, net energy costs, and peak blood lactate concentration ([BLa<sup>−</sup>]). With multivariate regression, four variables correlated with each criterion measures’ variance–lower leg length (LLL) and cross-sectional area (CSA), as well as the lengths of the triceps surae (ML) and Achilles tendon (ATL). Our predictor variables correlated to significant amounts of TW and net energy cost, but not [BLa<sup>−</sup>] variance. Univariate matrices showed CSA was the best overall predictor for our criterion measures, while ML and ATL were generally weaker correlates. ATL did not have as great an impact as with other lower leg exercises; likely because the slow rate of ankle joint movement greatly limited SEE activity. The limited degree of foot support for ergometer repetitions was also a factor that likely weakened ATL's impact as a correlate. More research on anatomy's impact on this novel form of exercise is warranted.</p>ARTICLE2020-07-20T00:00:00.000+00:00MMaJIC, an Experimental Chamber for Investigating Soldering and Brazing in Microgravity<p>An E-1 payload, the Microgravity Materials Joining Investigative Chamber (MMaJIC), was designed and built for use aboard the International Space Station to investigate soldering and brazing phenomena in a microgravity environment. MMaJIC is a self-contained unit employing a microcontroller that runs a pre-programed experiment, monitors safety sensors, and supports temperature and video recording. MMaJIC uses individual experiment trays that can be easily modified for a specific investigation. The trays, which include a temperature/video data acquisition card, can be easily changed out and returned to Earth for evaluation. Simple operation of MMaJIC minimizes astronaut time while ensuring maximum sample throughput. It is expected that the results will shed considerable light on soldering and brazing in low-gravity environments, information that is important for NASA in conducting comprehensive repair and/or fabrication operations during long duration space missions.</p>ARTICLE2020-07-21T00:00:00.000+00:00Hemodynamic and Neuroendocrinological Responses to Artificial Gravity<p>The aim of this study was to determine the hemodynamic and neuroendocrinological responses to different levels and protocols of artificial gravity, especially in comparison to what is expected during a moderate bout of exercise. Ten male participants were exposed to artificial gravity using two different protocols: the first was a centrifugation protocol that consisted of a constant phase of 2 Gz for 30 minutes, and the second consisted of an intermittent phase of 2 Gz for two minutes, separated by resting periods for three minutes in successive order. Near infrared spectroscopy (oxyhemoglobin and deoxyhemoglobin) at the prefrontal cortex, <italic>Musculus biceps brachii</italic>, and <italic>Musculus</italic> g<italic>astrocnemius</italic>, as well as heart rate and blood pressure were recorded before, during, and after exposure to artificial gravity. In order to determine effects of artificial gravity on neuroendocrinological parameters (brain-derived neurotrophic factor, vascular endothelial growth factor, and insulin-like growth factor 1), blood samples were taken before and after centrifugation. During the application of artificial gravity the concentration of oxyhemoglobin decreased significantly and the concentration of deoxyhemoglobin increased significantly in the prefrontal cortex and the <italic>Musculus biceps brachii</italic> muscle. Participants exposed to the continuous artificial gravity profile experienced peripheral pooling of blood. No changes were observed for brain-derived neurotrophic factor, vascular endothelial growth factor, or insulin-like growth factor 1. Intermittent application of artificial gravity may represent a better-tolerated presentation for participants as hemodynamic values normalize during resting periods. During both protocols, heart rate and arterial blood pressure remained far below what is experienced during moderate physical activity.</p>ARTICLE2020-07-21T00:00:00.000+00:00en-us-1