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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 181 records · Page 10
All sourcesNASA NTRSDOE OSTI
NASA NTRS1997

Neonatal rat heart cells cultured in simulated microgravity

In vitro characteristics of cardiac cells cultured in simulated microgravity are reported. Tissue culture methods performed at unit gravity constrain cells to propagate, differentiate, and interact in a two-dimensional (2D) plane. Neonatal rat cardiac cells in 2D culture organize predominantly as bundles of cardiomyocytes with the intervening areas filled by nonmyocyte cell types. Such cardiac cell cultures respond predictably to the addition of exogenous compounds, and in many ways they represent an excellent in vitro model system. The gravity-induced 2D organization of the cells, however, does not accurately reflect the distribution of cells in the intact tissue. We have begun characterizations of a three-dimensional (3D) culturing system designed to mimic microgravity. The NASA-designed High-Aspect Ratio Vessel (HARV) bioreactors provide a low shear environment that allows cells to be cultured in static suspension. HARV-3D cultures were prepared on microcarrier beads and compared to control-2D cultures using a combination of microscopic and biochemical techniques. Both systems were uniformly inoculated and medium exchanged at standard intervals. Cells in control cultures adhered to the polystyrene surface of the tissue culture dishes and exhibited typical 2D organization. Cells cultured in HARVs adhered to microcarrier beads, the beads aggregated into defined clusters containing 8 to 15 beads per cluster, and the clusters exhibited distinct 3D layers: myocytes and fibroblasts appeared attached to the surfaces of beads and were overlaid by an outer cell type. In addition, cultures prepared in HARVs using alternative support matrices also displayed morphological formations not seen in control cultures. Generally, the cells prepared in HARV and control cultures were similar; however, the dramatic alterations in 3D organization recommend the HARV as an ideal vessel for the generation of tissuelike organization of cardiac cells in vitro.

Non-NASA Center↗
NASA NTRS2011

Response of Human Prostate Cancer Cells to Mitoxantrone Treatment in Simulated Microgravity Environment

This study explores the changes in growth of human prostate cancer cells (LNCaP) and their response to the treatment of antineoplastic agent, mitoxantrone, under the simulated microgravity condition. In comparison to static 1g, microgravity and simulated microgravity have been shown to alter global gene expression patterns and protein levels in various cultured cell models or animals. However, very little is known about the effect of altered gravity on the responses of cells to drugs, especially chemotherapy drugs. To test the hypothesis that zero gravity would result in altered regulation of cells in response to antineoplastic agents, we cultured LNCaP cells for 96 hr either in a High Aspect Ratio Vessel (HARV) bioreactor at the rotating condition to model microgravity in space or in the static condition as a control. 24 hr after the culture started, mitoxantrone was introduced to the cells at a final concentration of 1 M. The mitoxantrone treatment lasted 72 hr and then the cells were collected for various measurements. Compared to static 1g controls, the cells cultured in the simulated microgravity environment did not show significant differences in cell viability, growth rate, or cell cycle distribution. However, in response to mitoxantrone (1uM), a significant proportion of bioreactor cultured cells (30%) was arrested at G2 phase and a significant number of these cells were apoptotic in comparison to their static controls. The expressions of 84 oxidative stress related genes were analyzed using Qiagen PCR array to identify the possible mechanism underlying the altered responses of bioreactor culture cells to mitoxantrone. Nine out of 84 genes showed higher expression at four hour post mitoxantrone treatment in cells cultured at rotating condition compared to those at static. Taken together, the results reported here indicate that simulated microgravity may alter the responses of LNCaP cells to mitoxantrone treatment. The alteration of oxidative stress pathways in cells cultured under simulated microgravity conditions may be one of the mechanisms to cause such changes of sensitivity of LNCaP cells to mitoxantrone treatment.

Zhang, Ye↗
NASA NTRS1990

Experiment K-6-22. Growth hormone regulation, synthesis and secretion in microgravity. Part 1: Somatotroph physiology. Part 2: Immunohistochemical analysis of hypothalamic hormones. Part 3: Plasma analysis

The objectives of the 1887 mission were: (1) to determine if the results of the SL-3 pituitary gland experiment (1) were repeatable; and (2) to determine what effect a longer mission would have on the rat pituitary gland growth hormone (GH) system. In the 1887 experiment two issues were considered especially important. First, it was recognized that cells prepared from individual rat pituitary glands should be considered separately so that the data from the 5 glands could be analyzed in a statistically meaningful way. Second, results of the SL-3 flight involving the hollow fiber implant and HPLC GH-variant experiments suggested that the biological activity of the hormone had been negatively affected by flight. The results of the 1887 experiment documented the wisdom of addressing both issues in the protocol. Thus, the reduction in secretory capacity of flight cells during subsequent extended cell culture on Earth was documented statistically, and thereby established the validity of the SL-3 result. The results of both flight experiments thus support the contention that there is a secretory lesion in pituitary GH cells of flight animals. The primary objective of both missions was a clear definition of the effect of spaceflight on the GH cell system. There can no longer be any reasonable doubt that this system is affected in microgravity. One explanation for the reason(s) underlying the better known effects of spaceflight on organisms, viz. changes in bone, muscle and immune systems may very well rest with such changes in bGH. In spite of the fact that rats in the Cosmos 1887 flight were on Earth for two days after flight, the data show that the GH system had still not recovered from the effects of flight. Many questions remain. One of the more important concerns the GRF responsiveness of somatotrophs after flight. This will be tested in an upcoming experiment.

Grindeland, R.↗
NASA NTRS2001

BNL accelerator-based radiobiology facilities

For the past several years, the Alternating Gradient Synchrotron (AGS) at Brookhaven National Laboratory (USA) has provided ions of iron, silicon and gold, at energies from 600 MeV/nucleon to 10 GeV/nucleon, for the US National Aeronautics and Space Administration (NASA) radiobiology research program. NASA has recently funded the construction of a new dedicated ion facility, the Booster Applications Facility (BAF). The Booster synchrotron will supply ion beams ranging from protons to gold, in an energy range from 40-3000 MeV/nucleon with maximum beam intensities of 10(10) to 10(11) ions per pulse. The BAF Project will be described and the future AGS and BAF operation plans will be presented.

NASA Discipline Radiation Health↗
NASA NTRS1999

Encapsulation system for the immunoisolation of living cells

The present invention is drawn to a composition of matter comprising high viscosity sodium alginate, cellulose sulfate and a multi-component polycation. Additionally, the present invention provides methods for making capsules, measuring capsule permeability to immunologically-relevant proteins and treating disease in an animal using encapsulated cells. Over one thousand combinations of polyanions and polycations were examined as polymer candidates suitable for encapsulation of living cells and thirty-three pairs were effective. The combination of sodium alginate, cellulose sulfate, poly(methylene-co-guanidine) hydrochloride, calcium chloride, and sodium chloride produced the most desirable results. Pancreatic islets encapsulated in this multicomponent capsule demonstrated glucose-stimulated insulin secretion in vitro and reversed diabetes without stimulating immune reaction in mice. The capsule formulation and system of the present invention allows independent adjustments of capsule size, wall thickness, mechanical strength and permeability, and offers distinct advantages for immunoisolating cells.

Wang, Taylor G.↗
NASA NTRS2011

Genotoxic Effects of Low- and High-LET Radiation on Human Epithelial Cells Grown in 2-D Versus 3-D Culture

Risk estimation for radiation-induced cancer relies heavily on human epidemiology data obtained from terrestrial irradiation incidents from sources such as medical and occupational exposures as well as from the atomic bomb survivors. No such data exists for exposures to the types and doses of high-LET radiation that will be encountered during space travel; therefore, risk assessment for space radiation requires the use of data derived from cell culture and animal models. The use of experimental models that most accurately replicate the response of human tissues is critical for precision in risk projections. This work compares the genotoxic effects of radiation on normal human epithelial cells grown in standard 2-D monolayer culture compared to 3-D organotypic co-culture conditions. These 3-D organotypic models mimic the morphological features, differentiation markers, and growth characteristics of fully-differentiated normal human tissue and are reproducible using defined components. Cultures were irradiated with 2 Gy low-LET gamma rays or varying doses of high-LET particle radiation and genotoxic damage was measured using a modified cytokinesis block micronucleus assay. Our results revealed a 2-fold increase in residual damage in 2 Gy gamma irradiated cells grown under organotypic culture conditions compared to monolayer culture. Irradiation with high-LET particle radiation gave similar results, while background levels of damage were comparable under both scenarios. These observations may be related to the phenomenon of "multicellular resistance" where cancer cells grown as 3-D spheroids or in vivo exhibit an increased resistance to killing by chemotherapeutic agents compared to the same cells grown in 2-D culture. A variety of factors are likely involved in mediating this process, including increased cell-cell communication, microenvironment influences, and changes in cell cycle kinetics that may promote survival of damaged cells in 3-D culture that would otherwise die or be rendered reproductively inactive in 2-D culture.

Patel, Z. S.↗
NASA NTRS1993

Overview of spaceflight immunology studies

The effects of spaceflight and analogues of spaceflight are discussed here and in nine accompanying articles. In this summary we present spaceflight studies with human subjects, animal subjects, and cell cultures and we review ground-based systems used to model the observed effects of spaceflight on the immune system. Human paradigms include bed rest, academic or psychological stress, physical stress, hypobaric or high altitude stress, and confinement. Animal models include antiorthostatic and orthostatic suspension, hypobarism, and confinement. The ten manuscripts in this collection were selected to provide a summary that should give the reader an overview of the various activities of spaceflight immunology researchers throughout the history of space travel. This manuscript identifies the major contributors to the study of spaceflight immunology, explains what types of studies have been conducted, and how they have changed over the years. Also presented is a discussion of the unusual limitations associated with spaceflight research and the efforts to develop appropriate ground-based surrogate model systems. Specific details, data, and mechanistic speculations will be held to a minimum, because they will be discussed in depth in the other articles in the collection.

NASA Discipline Number 18-10↗
NASA NTRS2000

Release of kinesin from vesicles by hsc70 and regulation of fast axonal transport

The nature of kinesin interactions with membrane-bound organelles and mechanisms for regulation of kinesin-based motility have both been surprisingly difficult to define. Most kinesin is recovered in supernatants with standard protocols for purification of motor proteins, but kinesin recovered on membrane-bound organelles is tightly bound. Partitioning of kinesin between vesicle and cytosolic fractions is highly sensitive to buffer composition. Addition of either N-ethylmaleimide or EDTA to homogenization buffers significantly increased the fraction of kinesin bound to organelles. Given that an antibody against kinesin light chain tandem repeats also releases kinesin from vesicles, these observations indicated that specific cytoplasmic factors may regulate kinesin release from membranes. Kinesin light tandem repeats contain DnaJ-like motifs, so the effects of hsp70 chaperones were evaluated. Hsc70 released kinesin from vesicles in an MgATP-dependent and N-ethylmaleimide-sensitive manner. Recombinant kinesin light chains inhibited kinesin release by hsc70 and stimulated the hsc70 ATPase. Hsc70 actions may provide a mechanism to regulate kinesin function by releasing kinesin from cargo in specific subcellular domains, thereby effecting delivery of axonally transported materials.

Non-NASA Center↗
NASA NTRS1996

Cytokines and macrophage function in humans - role of stress

We have begun this study to commence the determination of the role of mild chronic stress in the effects of space flight on macrophage/monocyte function, a component of the immune response. Medical students undergoing regular periods of stress and relaxation have been shown to be an excellent model for determining the effects of stress on immune responses. We have begun using this model using the macrophage/monocyte as model leukocyte. The monocyte/macrophage plays a central role in immunoregulation. The studies to be included in this three year project are the effects of stress on: (1) interactions of monocytes with microbes, (2) monocyte production of cytokines, (3) monocyte phagocytosis and activity, and (4) monocyte expression of cell surface antigens important in immune responses. Stress hormone levels will also be carried out to determine if there is a correlation between stress effects on immune responses and hormonal levels. Psychological testing to insure subjects are actually stressed or relaxed at the time of testing will also be carried out. The results obtained from the proposed studies should be comparable with space flight studies with whole animals and isolated cell cultures. When complete this study should allow the commencement of the establishment of the role of stress as one compartment of the induction of immune alterations by space flight.

Sonnenfeld, Gerald↗
NASA NTRS2002

Space flight nutrition research: platforms and analogs

Conducting research during actual or simulated weightlessness is a challenging endeavor, where even the simplest activities may present significant challenges. This article reviews some of the potential obstacles associated with performing research during space flight and offers brief descriptions of current and previous space research platforms and ground-based analogs, including those for human, animal, and cell-based research. This review is intended to highlight the main issues of space flight research analogs and leave the specifics for each physiologic system for the other papers in this section.

NASA Discipline Regulatory Physiology↗
NASA NTRS2012

Paramyxovirus Infection Mimics In Vivo Cellular Dynamics in Three-Demensional Human Bronchio-Epithelial Tissue-Like Assemblies

Respiratory syncytial virus and parainfluenza virus cause severe respiratory disease, especially in infants, children and the elderly. An in vitro model that accurately mimics infection of the human respiratory epithelium (HRE) would facilitate vaccine development greatly. Monolayer cultures traditionally used to study these viruses do not accurately and precisely differentiate the replication efficiencies of wild type and attenuated viruses. Therefore, we engineered novel three-dimensional (3D) tissue-like assemblies (TLAs) of human broncho-epithelial (HBE) cells to produce a more physiologically relevant in vitro model of the HRE. TLAs resemble HRE structurally and by expression of differentiated epithelial cell markers. Most significantly, wild type viruses exhibited a clear growth advantage over attenuated strains in TLAs unlike monolayer cultures. In addition, the TLAs responded to virus infection by secreting pro-inflammatory mediators similar to the respiratory epithelia of infected children. These characteristics make the TLA model a valuable platform technology to develop and evaluate live, attenuated respiratory virus vaccine candidates for human use. Respiratory virus diseases, the most frequent and least preventable of all infectious diseases, range in severity from the common cold to severe bronchiolitis and pneumonia . Two paramyxoviruses, respiratory syncytial virus (RSV) and parainfluenza virus type 3 (PIV3), are responsible for a majority of the most severe respiratory diseases of infants and young children. RSV causes 70% of all bronchiolitis cases and is a major cause of morbidity and mortality worldwide, especially in infants. PIV3 causes 10-15% of bronchiolitis and pneumonia during infancy, second only to RSV, and 40% of croup in infants To date, licensed vaccines are not available to prevent these respiratory diseases. At present, traditional monkey kidney (Vero and LLC-MK2) and human (HEp-2) tissue culture cells and small animal models (mouse, cotton rat, guinea pig, ferret, and hamster) fail to accurately imitate viral replication and human disease states (8). Lacking an authentic model has impeded the development and evaluation of live, attenuated vaccine candidates. Development of a physiologically relevant in vitro tissue culture model that reproduces characteristics of the HRE, the primary target of RSV and PIV3, would aid in predicting clinical attenuation and safety of vaccine candidates. Successful tissue engineering of a 3D human intestinal model using novel NASA technology inspired the development of a tri-culture 3D model for the HRE. Sequential layering of primary mesenchymal cells (comprised of normal human fibroblasts and endothelial cells) followed by BEAS-2B epithelial cells derived from human bronchi and tracheae were recapitulated on Cultisphere and/or cytodex3 microcarriers in cylindrical vessels that rotate horizontally creating an organized epithelial structure. Horizontal rotation randomizes the gravity vector modeling aspects of microgravity. Mesenchymal and epithelial cells grown under these conditions reproduce the structural organization, multi-cellular complexity, and differentiation state of the HRE. The opportunity to study respiratory viruses in a nasal epithelium model is invaluable because the most promising respiratory virus vaccine candidates are live attenuated viruses for intranasal administration. Here we characterize the interactions of respiratory viruses and epithelial cells grown under modeled microgravity in comparison to gravity-ladened monolayers. 3D HBE TLAs and traditional monolayers (2D) are infected at 35 C, the upper temperature of the upper HRE, to simulate in vivo infection conditions. Growth kinetics of wild type (wt) RSV and PIV3 viruses were compared in 2D and 3D cells to that of strains attenuated in humans or rhesus macaques. This novel 3D HBE model also offers an opportunity to study whether the epithelial cell function, especially in host defenses recapitulated by mimicking the structural organization of the HRE. In vivo, airway epithelial cells play a significant and dynamic role in host defense by blocking paracellular permeability and modulating airway function through cellular interactions or tight junctions. As regulators of the innate immune response, epithelial cells constitutively express cytokines, chemokines, and colony stimulating factors including RANTES, IL-8, IL-6, GM-CSF, and G-CSF for proactive host defense. In response to viral infection, epithelial cells induce potent immuno-modulatory and pro-inflammatory cytokines that recruit phagocytic and inflammatory cells to clear the virus and enhance protection. Although disease pathogenesis is classically attributed to the cytopathic effects of the pathogen, severe disease states associated with RSV and PIV3 are attributed to the inflammatory response, especially in infants. RSV is a potent inducer of cytokines and pro-inflammatory mediators in epithelial cells in vivo. A differentiated human epithelial model independent of the complete functional immune system will help elucidate the role of epithelial cells in respiratory disease. We reported here, virus and host cell interactions in 3D HBE TLAs are similar to that in vivo. Because the epithelial cell organization of the TLAs impacts not only the expression of airway epithelial characteristics, but also cellular communication, the TLAs represent a more physiologically relevant model of the HRE than BEAS-2B or other non-tumour monolayer models of respiratory disease. As a result, wild type respiratory viruses have a clear growth advantage over attenuated viruses in TLAs unlike traditional monolayers. In addition, the TLAs respond to wild type virus infection by secreting pro-inflammatory mediators characteristic of infected HRE. TLAs expressing microbial defense mechanisms provide an excellent model to study the interactions of respiratory pathogens with their host and to identify the innate immunity mediators. Therefore, 3D HBE TLAs offer advantages for the study of respiratory viruses and the development of viral vaccine candidates.

Deatly, Anne M.↗
NASA NTRS1983

Settling of fixed erythrocyte suspension droplets

It is pointed out that when particles behave collectively rather than individually, the fractionation of micron-size particles on the basis of size, density, and surface characteristics by centrifugation and electrophoresis is hindered. The formation and sedimentation of droplets containing particles represent an extreme example of collective behavior and pose a major problem for these separation methods when large quantities of particles need to be fractionated. Experiments are described that measure droplet sizes and settling rates for a variety of particles and droplets. Expressions relating the particle concentration in a drop to measurable quantities of the fluids and particles are developed. The number of particles in each droplet is then estimated, together with the effective droplet density. Red blood cells from different animals fixed in glutaraldehyde provide model particle groups.

Omenyi, S. N.↗
NASA NTRS1990

Experiment K-6-16. Morphological examination of rat testes. The effect of Cosmos 1887 flight on spermatogonial population and testosterone level in rat testes

Testes from rats flown on Cosmos 1887 for twelve and a half days were compared to basal control, synchronous control and vivarium maintained rats. When the mean weights of flight testes, normalized for weight/100 gms, were compared to the vivarium controls they were 6.7 percent lighter. Although the flight testes were lighter than the synchronous, the difference is not significant. Counts of spermatogonial cells from 5 animals in each group revealed a 4 percent decrease in flight compared to vivarium controls. In both cases the t-Test significance was less than 0.02. The serum testosterone levels of all animals (flight, synchronous and vivarium) were significantly below the basal controls.

Philpott, D. E.↗
NASA NTRS1993

Potential health effects of space radiation

Crewmembers on missions to the Moon or Mars will be exposed to radiation belts, galactic cosmic rays, and possibly solar particle events. The potential health hazards due to these space radiations must be considered carefully to ensure the success of space exploration. Because there is no human radioepidemiological data for acute and late effects of high-LET (Linear-Energy-Transfer) radiation, the biological risks of energetic charged particles have to be estimated from experimental results on animals and cultured cells. Experimental data obtained to date indicate that charged particle radiation can be much more effective than photons in causing chromosome aberrations, cell killing, mutation, and tumor induction. The relative biological effectiveness (RBE) varies with biological endpoints and depends on the LET of heavy ions. Most lesions induced by low-LET radiation can be repaired in mammalian cells. Energetic heavy ions, however, can produce large complex DNA damages, which may lead to large deletions and are irreparable. For high-LET radiation, therefore, there are less or no dose rate effects. Physical shielding may not be effective in minimizing the biological effects on energetic heavy ions, since fragments of the primary particles can be effective in causing biological effects. At present the uncertainty of biological effects of heavy particles is still very large. With further understanding of the biological effects of space radiation, the career doses can be kept at acceptable levels so that the space radiation environment need not be a barrier to the exploitation of the promise of space.

Yang, Chui-Hsu↗
NASA NTRS1994

The Influence of Sound Cues on the Maintenance of Temporal Organization in the Sprague-Dawley Rat

Temporal organization is a fundamental property of living matter. From single cells to complex animals including man, most physiological systems undergo daily periodic changes in concert with environmental cues (e.g., light, temperature etc.). It is known that pulsed Environmental synchronizers, zeitgebers, (e.g. light) can modify rhythm parameters. Rhythm stability is a necessary requirement for most animal experiments. The extent to which sound can influence the circadian system of laboratory rats is poorly understood. This has implications to animal habitats in the novel environments of the Space-Laboratory or Space Station. A series of three white noise (88+/-0.82 db) zeitgeber experiments were conducted (n=6/experiment).The sound cue was introduced in the circadian free-running phase (DD-NQ) and in one additional case sound was added to the usual photoperiod (12L:12D) to determine masking effects. Circadian rhythm parameters of drinking frequency, feeding frequency, and gross locomotor activity were continuously monitored. Data analysis for these studies included macroscopic and microscopic methods. Raster plots to visually detect entrainment versus free-running period, were plotted for each animal, for all three parameters, during all sound perturbation tested. These data were processed through a series of detrending (robust locally weighted regression analyses) and complex demodulation analyses. In summary, these findings show that periodic "white" noise "influences" the rats circadian system but does not "entrain" the feeding, drinking or locomotor activity rhythms.

Winget, C. M.↗
NASA NTRS2002

How Osteoblasts Sense their Environment: Integrin-Extracellular Matrix Interactions and Mechanical Loading of Bone

Osteoblasts are the cells responsible for forming and replacing bone throughout life. We know that mechanical stimulation through weight-bearing at I gravity on Earth is needed to maintain healthy bone, and that osteoblasts play a critical role in that process. Over the last 9 years in my laboratory at NASA ARC, we have studied the regulation of osteoblast function by interactions between the extracellular matrix and die cell. Using a cell culture approach, we defined the repertoire of adhesion receptors, called integrins, which are expressed on the osteoblast surface, as well as specific extracellular matrix proteins, which are needed for cellular differentiation and survival. We are now extending these observations to determine if integrin signaling is involved in the skeletal responses to disuse and recovery from disuse using the rodent model of hindlimb unloading by tail suspension. Together, our cell culture and animal studies are providing new insight into the regulation of osteoblast function in bone.

Globus, Ruth K.↗
NASA NTRS2002

Population dynamics during cell proliferation and neuronogenesis in the developing murine neocortex

During the development of the neocortex, cell proliferation occurs in two specialized zones adjacent to the lateral ventricle. One of these zones, the ventricular zone, produces most of the neurons of the neocortex. The proliferating population that resides in the ventricular zone is a pseudostratified ventricular epithelium (PVE) that looks uniform in routine histological preparations, but is, in fact, an active and dynamically changing population. In the mouse, over the course of a 6-day period, the PVE produces approximately 95% of the neurons of the adult neocortex. During this time, the cell cycle of the PVE population lengthens from about 8 h to over 18 h and the progenitor population passes through a total of 11 cell cycles. This 6-day, 11-cell cycle period comprises the "neuronogenetic interval" (NI). At each passage through the cell cycle, the proportion of daughter cells that exit the cell cycle (Q cells) increases from 0 at the onset of the NI to 1 at the end of the NI. The proportion of daughter cells that re-enter the cell cycle (P cells) changes in a complementary fashion from 1 at the onset of the NI to 0 at the end of the NI. This set of systematic changes in the cell cycle and the output from the proliferative population of the PVE allows a quantitative and mathematical treatment of the expansion of the PVE and the growth of the cortical plate that nicely accounts for the observed expansion and growth of the developing neocortex. In addition, we show that the cells produced during a 2-h window of development during specific cell cycles reside in a specific set of laminae in the adult cortex, but that the distributions of the output from consecutive cell cycles overlap. These dynamic events occur in all areas of the PVE underlying the neocortex, but there is a gradient of maturation that begins in the rostrolateral neocortex near the striatotelencephalic junction and which spreads across the surface of the neocortex over a period of 24-36 h. The presence of the gradient across the hemisphere is a possible source of positional information that could be exploited during development to establish the areal borders that characterize the adult neocortex.

Non-NASA Center↗